Abstract: We demonstrate a design of all-ferrodielectric
metasurface which exhibit sufficient enhancement of the Faraday
rotation induced by particular grating mode excitation [1,2]. The
metasurface is presented as periodic arrangement of cylinders
(open dielectric resonators) which located on the substrate and
both made of ferrodielectric. The conditions of the grating mode
excitation are revealed for different geometrical parameters of
the resonators forming the array. It was established that the
Faraday rotation [3,4] is increased in several times versus
uniform ferrodielectric layer with the same thickness at the
corresponding resonant frequency. The effect is confirmed in the
microwave measurements.
[1] V. I. Belotelov, I. A. Akimov, M.
Pohl, V. A. Kotov, S. Kasture, A. S. Vengurlekar, A. V. Gopal, D.
R. Yakovlev, A. K. Zvezdin, and M. Bayer, “Enhanced
magneto-optical effects in magnetoplasmonic crystals,” Nature
Nanotechnology 6, 370-376 (2011).
[2] A. V. Chetvertukhin, A. A.
Grunin, A. V. Baryshev, T. V. Dolgova, H. Uchida, M. Inoue, and A.
A. Fedyanin, “Magneto-optical Kerr effect enhancement at the
Wood’s anomaly in magnetoplasmonic crystals,” J. Magn. Magn.
Mater. 324, 21, 3516–3518 (2012).
[3] M. Inoue, M. Levy, and A. V.
Baryshev, (Eds.). Magnetophotonics: From Theory to Applications
(Springer Science
Business Media, 2013).
[4] A. A. Girich, S. Y.
Polevoy, S. I. Tarapov, A. M. Merzlikin, A. B. Granovsky, and D.
P. Belozorov, “Experimental Study of the Faraday Effect in
1D-Photonic Crystal in Millimeter Waveband,” Solid State Phenomena
190, 365-368 (2012).
Chair: prof. Sławomir Mamica
Seminar language: English
/546/
Date: Monday, 18 Nov 2019 at 10:30-10:45
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: B.Sc. Mateusz Gołębiewski
Authors: Mateusz Gołębiewski, Paweł Gruszecki, Andriy
Serebryannikov, and Maciej Krawczyk.
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Spin-wave Talbot effect in thin ferromagnetic film
Abstract: Demonstration, in micromagnetic simulation, the
self-imaging phenomenon (called the Talbot effect) for spin waves
propagation in thin ferromagnetic film magnetized out-of-plane. We
show that the diffraction grating created by the holes in thin
permalloy film allows obtaining Talbot’s carpets formed by the
transmitted spin waves at high frequencies, where the exchange
interactions dominate, and at low frequencies where the
magnetostatic interactions influence the shape of the dispersion
relation. The analyzed effect is particularly interesting due to
the potential application in magnonic devices, e.g. logic
circuits.
Chair: Prof. Sławomir Mamica
Seminar language: English
/545/
Date: Monday, 18 Nov 2019 at 10:50-11:05
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: B.Sc. Krzysztof Sobucki
Authors: Krzysztof Sobucki, Pawel Gruszecki, and Maciej Krawczyk.
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Subwavelength control of the phase of spin waves by
ferromagnetic resonators
Abstract: Phase and amplitude are the fundamental characteristics
of spin waves that can be used to carry information. We propose
here a method of the modulation of the phase of reflected spin
waves from the edge of a thin ferromagnetic film. Utilizing
micromagnetic simulations, we demonstrate that the application of
narrow resonators on top of the edges can be used to mold the
phase of the reflected waves. We show that near the Fano
resonances, even small change of the resonator’s geometry
significantly influences the phase of the reflected waves.
Noteworthy, this resonator can be treated as a magnonic
counterpart of metasurface since it enables spin waves modulation,
i.e., manipulation of the phase at subwavelength distances.
Chair: Prof. Sławomir Mamica
Seminar language: English
/544/
Date: Friday, 15 Nov 2019 at 9:00-9:20
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Jakób Walowski
Authors: Maria Mansurova, Jakób Walowski, Henning Ulrichs, and
Markus Münzenberg.
Affiliation of the presenting author:
Universität Greifswald, Germany
Title: Spin-wave packets triggered by ultrashort laser pulses
Abstract: We investigate Broadband excitations of spin-wave
packets by ultrashort laser pulses at different magnonic antidot
crystals and continuous magnetic film interfaces exhibit surface
spin-wave modes that propagate out of the crystal into the
continuous film. The propagation distance depends on the direction
of the applied magnetic field as well as the surface geometry of
the crystal. Additionally, Spatially resolved measurements of the
magnetization dynamics on thin CoFeB films reveal that the
frequencies of resulting spin-wave modes depend strongly on the
distance to the pump center. This can be attributed to a laser
generated temperature profile. We determine a shift of 0.5 GHz in
the spin-wave frequency due to the spatial thermal profile induced
by the femtosecond pump pulse that persists for up to one
nanosecond.
Chair: Dr. Paweł Gruszecki
Seminar language: English
/543/
Date: Friday, 15 Nov 2019 at 9:25-9:45
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Joachim Gräfe
Affiliation of the presenting author: Max Planck Institute for
Intelligent Systems, Stuttgart, Germany
Title: Imaging nanoscale spin dynamics using x-ray microscopies
Abstract: State of the art x-ray microscopy allows an
unprecedented insight into dynamic magnetic systems, featuring a
spatial resolution of 20 nm and a temporal resolution of 20 ps.
This technique uniquely allows us real space observation of
artificial spin systems that have been created using contemporary
nanolithography methods. To this end we have developed
sophisticated measurement and evaluation techniques that allow the
fast acquisition of full spin wave dispersion relations and the
quantitative measurement of minute spin angles. We showcase this
technique with three examples: magnetic droplets, magnetic
skyrmions, and short wavelength spin waves.
Chair: Dr. Paweł Gruszecki
Seminar language: English
/542/
Date: Friday, 15 Nov 2019 at 9:50-10:10
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Justyna Rychły
Authors: F. Lisiecki, J. Rychły, P. Kuswik, H.Glowiński, J. W.
Kłos, F. Gross, N. Trager, I. Bykova, M. Weigand, M. Zelent, E. J.
Goering, G. Schutz, G. Gubbiotti, M. Krawczyk, F. Stobiecki, J.
Dubowik, and J. Grafe.
Affiliation of the presenting author: Institute of Molecular
Physics, Polish Academy of Sciences, Poznań, Poland
Title: 1D Fibonacci magnonic quasicrystals –self-similarity of
spin wave spectra, spin waves localization, andreprogrammability
Abstract: Quasicrystals are structures that exhibit long-range
order, lack translational periodicity, but possess another
noteworthy symmetry property, which is self-similarity by scaling
[1]. Therefore, magnonic quasicrystals surpass regular magnonic
crystals regarding provided by them possibilities of spin waves
control: they offer complex, self-similar spin wave spectra,
localization of spin waves inside the structure, and on the
surfaces of the structure [2]. The results of joint collaborative
research with the experimental groups will be shown, demonstrating
the possibility of spin wave propagation through magnonic
quasicrystal, the opening of additional mini-bandgaps [3], and the
reprogrammability of the resonance frequencies, dependent on the
magnetization order in magnonic quasicrystals [4]. The
measurements of SWs propagating in a 1D Fibonacci sequence of
dipolarly coupled permalloy nanowires are done with the help of a
combined X-ray microscopic and Brillouin Light Scattering. The
experimental results are interpreted using numerical calculations.
Additionally, a simple model estimating frequencies of magnonic
gaps in the spin wave spectra of the Fibonacci quasiperiodic
structure matches the frequency mini-band gaps calculated
numerically and measured experimentally. The demonstrated features
of one-dimensional magnonic quasicrystals allow utilizing this
class of metamaterials for magnonics and make them an ideal basis
for future applications. We would like to acknowledge the European
Union’s Horizon 2020 research and innovation program under the
Marie Skłodowska-Curie GA Grant No. 644348 (MagIC) and NCN Poland
Grant No. UMO2017/24/T/ST3/00173, No. UMO-2012/07/E/ST3/00538, and
No. UMO-2016/21/B/ST3/00452, Helmholtz Zentrum Berlin/BESSY II is
gratefully acknowledged for allocating beam time at the MAXYMUS
end station. J.R. would like to additionally acknowledge the
financial support from the Adam Mickiewicz University Foundation.
[1] C. Janot, Quasicrystals: A Primer 2nd edition, Oxford University Press, 2012
[2] J. Rychły, J. W. Kłos, M. Mruczkiewicz, M. Krawczyk, Spin waves in one-dimensional bicomponent magnonic quasicrystals, Physical Review B 92, 054414 (2015)
[3] Filip Lisiecki, Justyna Rychły, Piotr Kuświk, Hubert Głowiński, Jarosław W. Kłos, Felix Groß, Nick Trager, Iuliia Bykova, Markus Weigand, Mateusz Zelent, Eberhard J. Goering, Gislea Schutz, Maciej Krawczyk, Feliks Stobiecki, Janusz Dubowik, and Joachim Gräfe, Magnons in a Quasicrystal: Propagation, Extinction, and Localization of Spin Waves in Fibonacci Structures, Phys. Rev. Applied 11, 054061 (2019)
[4] F. Lisiecki, J. Rychły, P. Kuswik, H. Glowiński, J. W. Kłos, F. Groß, I. Bykova, M. Weigand, M. Zelent, G. Schutz, G. Gubbiotti, M. Krawczyk, F. Stobiecki, J. Dubowik, and J. Grafe, Reprogrammability and scalability of Fibonacci magnonic quasicrystal, Physical Review Applied 11, 054003 (2019)
Chair: Dr. Paweł Gruszecki
Seminar language: English
/541/
Date: Friday, 15 Nov 2019 at 10:30-10:50
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Andrzej Janutka
Affiliation of the presenting author: Department of Theoretical
Physics, Wrocław University of Science and Technology, 50-370
Wrocław, Poland
Title: Magnetoreactance at the nanoscale
Abstract: Magnetoreactance is a magnetic-field dependence of the
imaginary part of the electrical impedance. While giant
magnetoimpedance (GMI) of ferromagnetic microwires or sandwiched
multilayers is being widely applied for sensing magnetic field
with a superior field sensitivity, it is suppressed at the
nanoscale in the accessible (microwave) range of the current
frequency, which limits the spatial resolution of the sensors. A
giant magnetoreactance (GMX), that is assisted by driven
oscillations of the ferromagnetic domain walls, is an alternative
to GMI when miniaturizing the field sensor. Efficiency of GMX is
studied for several nanomagnetic systems by means of micromagnetic
simulations.
[1] A. Janutka, K. Brzuszek, JMMM 465 (2018)
437.
[2] A. Janutka, K. Brzuszek, J. Phys. D 52 (2019)
035003.
[3] A. Janutka, K. Brzuszek, IEEE Magn. Lett. 10
(2019) 6103105.
Chair: Dr. Joachim Gräfe
Seminar language: English
/540/
Date: Friday, 15 Nov 2019 at 10:55-11:15
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Emerson Coy
Affiliation of the presenting author: NanoBioMedical Centre, Adam
Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614 Poznań,
Poland
Title: Nanoindentation Applications for Oxide Electronics
Abstract: Nanoindentation is a well-established characterization
technique for the extraction of mechanical information of
nanomaterials. Nevertheless, much of the potential of the
technique is still overlooked by the functional oxides and the
electronics community, due to traditional preconceptions about
their applicability and use. In this talk, some of the unique
capabilities of the technique will be discussed. Followed by
specific applications on different materials such as
flexoelectric, ferroelectric and ferromagnetic. Finally, the
potential of nanoindentation as a powerful tool for information
technology, energy, and communications, will be presented.
Chair: Dr. Joachim Grafe
Seminar language: English
/539/
Date: Friday, 15 Nov 2019 at 11:20-11:40
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Andrzej Wawro
Authors: A. Wawro, Z. Kurant, M. Tekielak, M. Jakubowski, E.
Milińska, I. Sveklo, P. Mazalski, R. Böttger, A. Maziewski.
Affiliation of the presenting author:
Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
Title: Spatial ion beam modifications of Co layered structures – a
recipe for magnonic crystals
Abstract: Magnetic properties of a single Co layer depend on its
thickness and a type of buffer and capping film [1]. In
multilayered systems magnetic configurations are more complex due
to interlayer coupling depending on the nonmagnetic spacer
thickness [2]. Irradiation of such structures with an ion beam
substantially affects anisotropy, the coupling strength or type
and even suppresses their ferromagnetic nature [3,4]. Application
of a focus ion beam enables local magnetic modifications in the
nanometre scale leading to 3D magnonic crystals (MC) creation.
Several types of MCs are proposed for various stacks of the sample
and applied fluence of the ion beam.
Acknowledgements: This
work was supported by the National Science Centre in Poland under
the projects: 2014/13/B/ST5/01834 and the EU European Regional
Development Fund (REINTEGRATION 2017 OPIE 14-20).
[1] A.
Wawro et al., J. Phys. D 50, 215004 (2017)
[2] Z. Kurant et
al., J. Magn. Magn. Mat. 475, 683 (2019)
[3] A. Maziewski
et al., Phys. Rev. B 85, 054427(2012)
[4] A. Wawro et al.,
Phys. Rev. Appl. 9, 014029 (2018)
Chair: prof. Joachim Grafe
Seminar language: English
/538/
Date: Friday, 15 Nov 2019 at 11:45-12:05
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Ewelina Milińska
Authors: Ewelina Milińska, Sukanta Kumar Jena, Marcin Jakubowski,
Aleksiej Pietruczik, Roman Minikayev, Sabina Lewińska, Artem
Lynnyk, Pavlo Aleshkevych, Anuj Dhiman, Zbigniew Kurant, Iosif
Sveklo, Andrzej Maziewski, Andrzej Wawro .
Affiliation of the presenting author: Institute of Physics, Polish
Academy of Sciences, Warsaw, Poland
Title: Magnetization reversal, domain structure and ferromagnetic
resonance of heavy metal/ferromagnetic heterostructures
Abstract: Inversion-Asymmetric heterostructures have been
fabricated by molecular beam epitaxy (MBE) technique, in which Co
magnetic layer is surrounded by Pt and W material. The W/Co/Pt and
Pt/Co/W systems exhibit the high spin-orbit coupling (SOC) and
iDMI (interfacial Dzyaloshinskii Moriya interaction). The
labyrinth-like magnetic domains observed in as-deposited the
W/Co/Pt multilayers evolve into parallel stripe domain structure
(forming 1D magnonic crystals) after saturation in the magnetic
field applied in the sample plane, followed by an inplane ac
demagnetization with decreasing amplitude. The average width of
the labyrinth and parallel strip domains decrease with the
repetition number of multilayers. Additionally, FMR and VNA-FMR
spectra reveal resonance lines originating from uniform
ferromagnetic precession (above saturation field) and from stripe
labyrinth domain structure below the saturation field. Obtained
results give insight into the dynamics properties of the samples
which can be considered as MCs.
Acknowledgements: This work
was supported by the EU European Regional Development Fund
(REINTEGRATION 2017 OPIE 14-20).
Chair: Joachim Grafe
Seminar language: English
/537/
Date: Friday, 15 Nov 2019 at 13:40-14:00
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Ryszard Gieniusz
Authors: Ryszard Gieniusz, Michał Matczak, Anuj K. Dhiman, Iosif
Sveklo, Zbigniew Kurant, Urszula Guzowska, Feliks Stobiecki,
Andrzej Maziewski
Affiliation of the presenting author: Faculty of Physics,
University of Bialystok, Bialystok, Poland
Title: Magnetooptical and Brillouin Light Scattering studies of
ultrathin Co wedges with Pt and Ir covers
Abstract: Ir/Co/Pt and Pt/Co/Ir trilayers with a wedged Co layer
(Co thickness d=0±3.6nm) were deposited by magnetron sputtering on
naturally oxidized Si substrates with a Ta/Au buffer. Their
magnetic properties have been investigated using magneto-optical
polar Kerr effect and Brillouin light scattering (BLS) technique
in the Damon-Eshbach geometry. We have employed Brillouin Light
Scattering spectroscopy in backscattering geometry for DMI
constant DS and spectral linewidths studies. DS was nearly
two times larger for the Ir/Co/Pt trilayer than for the Pt/Co/Ir
with opposite chirality. The effective uniaxial magnetic
anisotropy and DS depend non-monotonically on d with a maximum
at d ≈ 1.2 nm. The asymmetry in linewidth for Stokes and
anti-Stokes peaks is observed for both Ir/Co/Pt and Pt/Co/Ir
trilayers for d < 1.6 nm, and it is increasing with decrease of
Co thickness. Acknowledgements: Supported by Polish National
Science Center projects: DEC-2016/23/G/ST3/04196 Beethoven and
UMO-2018/28/C/ST5/00308 SONATINA.
Chair: Dr. Hubert Głowiński
Seminar language: English
/536/
Date: Friday, 15 Nov 2019 at 14:05-14:20
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. A.K. Dhiman
Authors: A.K. Dhiman, R. Gieniusz, H.Głowiński, Z. Kurant, M.
Matczak, F. Stobiecki, I.Sveklo, M.Tekielak, A.Maziewski.
Affiliation of the presenting author: Faculty of Physics,
University of Białystok, Białystok, Poland
Title: Magnetic properties of Ir/Co/Pt and Pt/Co/Ir multilayers
with Dzyaloshinskii- Moriya interaction
Abstract: [Co(dCo)/Pt(dPt)/Ir(dIr)]N and
[Co(dCo)/Ir(dIr)/Pt(dPt)]N multilayers were
deposited by magnetron sputtering. Different dCo was chosen to
approach spin reorientation transition SRT from perpendicular to
in-plane magnetization state. Different coupling between layers
was obtained changing spacer layers thicknesses dIr and dPt.
Investigation of magnetic characterization was done using
longitudinal and polar magneto-optical Kerr effect MOKE, vibrating
sample magnetometer VSM, Brillouin light scattering BLS
spectroscopy, magnetic force microscopy MFM, VNA-FMR and FMR
spectroscopy. The following magnetization distribution was deduced
from magnetization curves and magnetic domain imaging: large
macrodomain (micrometer size) differentiated by inplane “core”
magnetization modulated by small nano-domain differentiated by
out-of-plane magnetization. Hysteresis of BLS signal (measured
also without magnetic field) was found. The in-plane “core”
magnetization in domains seems to be responsible for BLS signal.
Work supported by Polish National Science Center projects:
DEC-2016/23/G/ST3/04196 Beethoven and UMO- 2018/28/C/ST5/00308
SONATINA.
Chair: Dr. Hubert Głowiński
Seminar language: English
/535/
Date: Friday, 15 Nov 2019 at 14:25-14:45
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Jan Kisielewski
Authors: J. Kisielewski, P. Gruszecki, M. Krawczyk, and
A.Maziewski .
Affiliation of the presenting author:
Faculty of Physics, University of Bialystok, Bialystok, Poland
Title: Mapping magnetic textures in films with
Dzyaloshinskii-Moriya interaction.
Abstract: Exploiting the results of micromagnetic simulations, I
will demonstrate the effect of Dzyaloshinskii-Moriya interaction
(DMI) on static and dynamic magnetic properties of ultrathin
single films and multilayer systems. Beside a DMI magnitude, other
parameters were also adjusted, like the perpendicular magnetic
anisotropy (characterized by the quality factor Q) and external
magnetic field. Playing with the parameters, several types of
magnetic textures were observed: domains with narrow wall of
either Bloch or Neel type, spin spirals, skyrmions, conical spin
spirals, or in-plane magnetization configuration. Multilayer
systems were also modeled with different types of nonmagnetic
spacers, and different coupling between magnetic films, what led
to even more interesting variety of possible magnetization states.
The structures were also characterized by their magnetic
susceptibility and resonant oscillations of magnetization.
Acknowledgements: Work supported by Polish National Science Center
project DEC-2016/23/G/ST3/04196 Beethoven.
Chair: Dr. Hubert Głowiński
Seminar language: English
/534/
Date: Friday, 15 Nov 2019 at 15:05-15:25
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Mirosław Werwiński
Affiliation of the presenting author:
Institute of Molecular Physics, Polish Academy of Sciences,
Poznań, Poland
Title: Magnetocrystalline anisotropy of L10FeNi from DFT
Abstract: This contribution presents the results of ab initio
calculations of selected magnetic parameters of the L10 FeNi
phase, which are the magnetocrystalline anisotropy energies
(MAEs), the full potential calculations of the anisotropy constant
K3, spin and orbital magnetic moments, and the magnetostrictive
coefficient λ001 [1]. Furthermore, the calculated 3D
k-resolved map of the MAE combined with the Fermi surface analysis
gives a complete picture of the MAE contributions in the Brillouin
zone. To increase the certainty of the result, the MAEs were
calculated by using three different ab initio codes. All three
codes employ the full potential and generalized gradient
approximation (GGA) and give the MAEs below 0.5 MJ m−3. It is
expected that due to the limitations of the GGA this values are
underestimated. The more reliable model including orbital
polarization corrections doubles this value [2], whereas the
experimental values of the anisotropy constant K1 from the
literature oscillate around 1.0 MJ m−3 [3]. The L10 FeNi
has further potential to improve its MAE by modifications, like
for example tetragonal strain or alloying.
[1] M. Werwiński and W. Marciniak 2017 J. Phys. D: Appl.
Phys. 50 495008
[2] Y. Miura, S. Ozaki, Y. Kuwahara, M.
Tsujikawa, K. Abe, M. Shirai, 2013 J. Phys.: Condens. Matter 25
106005
[3] L.H. Lewis, F.E. Pinkerton, N. Bordeaux, A. Mubarok, E.
Poirier, J.I. Goldstein, R. Skomski, K. Barmak 2014 IEEE MAGNETICS
LETTERS 5 5500104.
Chair: Dr. Emerson Coy
Seminar language: English
/533/
Date: Friday, 15 Nov 2019 at 15:30-15:45
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. Piotr Rzeszut
Authors: Piotr Rzeszut, Witold Skowroński, Sławomir Zietek, Jakub
Checiński, Jerzy Wrona and Tomasz Stobiecki .
Affiliation of the presenting author: AGH University of Science
and Technology, Department of Electronics, 30-059 Kraków, Poland
Title: Serially connected perpendicular magnetic tunnel junctions
for multi-bit STTMRAM storage cells and neuromorphic computing
Abstract: One of the main limitation of the storage density of a
contemporary MRAM cell is the size of the transistor capable of
driving sufficiently high current density needed to switch
magnetic tunnel junction (MTJ). This limitation can be overcome by
using so-called multi-bit MRAM cell. We present a method of
manufacturing such multi-bit cells [1] with use of serially
connected standard MTJs. The device may also be used as a
memristor in neuromorphic computing [2-3]. Such design is very
simple to manufacture, but due to spread of parameters of MTJ some
limitations are observed. Mainly an ability to distinguish
adjacent resistance states is reduced as well as define voltages
for writing reduces as more non-equal elements are connected. To
address this issue a way to determine maximum capacity of such
multi-bit cell is needed. Therefore we also propose a behavioural
simulation of such multi-bit cells. We also present complete
analysis of limitations of the design. Scientific work funded from
budgetary funds for science in 2017-2018, as a research project
under the “Diamond Grant” program (Polish Ministry of Science and
Higher Education Diamond Grant No. 0048/DIA/2017/46).
This
work is supported by the Polish National Center for Research and
Development grant No. LIDER/467/L- 6/14/NCBR/2015. T.S.
acknowledges the SPINORBITRONICS grant No. 2016/23/B/ST3/01430.
[1] Rzeszut, P. et al. J. Appl. Phys. 125 (2019): 223907
[2] Torrejon, J. et. al. Nature 547 (2017): 428-431 [3] Raymenants, E.
et. al. J. Appl. Phys. 124 (2018): 152116
Chair: Dr. Emerson Coy
Seminar language: English
/532/
Date: Friday, 15 Nov 2019 at 15:50-16:10
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Piotr Graczyk
Authors: Piotr Graczyk and Maciej Krawczyk
Affiliation of the presenting author: Institute of Molecular
Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179
Poznań, Poland
Title: Nonresonant amplification of coherent spin waves through
voltage-induced interface magnetoelectric effect and spin-transfer
torque
Abstract: Spin waves are a promising candidates as a carriers for
the next-generation low-energy signal processing devices. Here, we
present the operation and we analyze the performance of the device
which amplifies and modulates the spin wave by the ac electric
field through the spin-transfer torque. Although the spin-transfer
torque is regarded as a non-selective effect, i.e., it affects all
the spin-wave modes together with noise, in our work we
investigate the mechanism of this torque which is related to the
specific spin wave symmetry and group velocity. As a consequence,
it affects only coherent spin-wave modes but not noise. The system
consists of two high-κ dielectric thin-film capacitors
separated by ferromagnetic bilayer. The magnetization dynamics is
affected non-resonantly with an ac voltage applied to such
heterostructure by the spin accumulation. The spin accumulation is
generated by the charge-mediated magnetoelectric effect (i.e.,
spin-dependent surface screening) and interacts with magnetization
through the so-called field-like and anti-damping spin transfer
torques. The spin transfer torques lead to the periodic spin wave
amplification and attenuation with the frequency of the applied ac
voltage. We show the criteria for the effective amplification and
dependences of the obtained gain on the applied voltage amplitude
and spin wave frequency. The generation of non-equilibrium spin
density through dynamic spin-dependent surface screening in the
proposed magnetoelectric heterostructure allows to reduce the
thickness of fixed magnetization layer used in conventional spin
valve to a few nanometers, thus the proposed effect can
significantly contribute to miniaturization of the spintronic
devices. The study has received financial support from the
National Science Centre of Poland under grant 2018/28/C/ST3/00052.
[1] P. Graczyk, M. Krawczyk, Spin-polarized currents driven by
spin-dependent surface screening, arXiv:1902.06481
Chair: Dr. Emerson Coy
Seminar language: English
/531/
Date: Friday, 15 Nov 2019 at 16:15-16:35
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Hubert Głowiński
Authors: Hubert Głowiński, Piotr Kuświk, Filip Lisiecki, and
Błażej Anastaziak
Affiliation of the presenting author: Institute of Molecular
Physics, Polish Academy of Sciences, Poznań, Poland
Title: Ion bombardment influence on magnetization damping
Abstract: Both anisotropy and damping is a function of spin-orbit
coupling (SOC). It is commonly observed that the damping increases
with increasing perpendicular magnetic anisotropy (PMA). It is
believed that this is due to their relation to SOC. We have
studied Au/Co/Au samples after ion bombardment, which is a known
method to modify PMA. We have found that although PMA changes
significantly nonmonotonically with ion fluence, the damping
changes monotonically. In summary, we believe that the connection
between damping and PMA is not a simple relation to SOC. This work
was supported by DAAD within the program PPP Polen 2018 under
Grant No. 57392264
Chair: Dr. Emerson Coy
Seminar language: English
/530/
Date: Friday, 15 Nov 2019 at 16:40-17:00
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Piotr Kuświk
Authors: Piotr Kuświk, Błażej Anastaziak, Łukasz Frąckowiak,
Michał Matczak, Gabriel David Chaves-O’Flynn, Maciej Urbaniak,
Paweł Piotr Michałowski, Arno Ehresmann, and Feliks Stobiecki .
Affiliation of the presenting author: Institute of Molecular
Physics, Polish Academy of Sciences, Poznań, Poland
Title: Local modification of magnetic properties for potential
applications in magnonics
Abstract: The development of new methods to modify magnetic
properties is important in many areas. In particular, this applies
to magnonics, where artificial modulation of magnetic parameters
can be used to control and manipulate spin waves. Here, we present
two methods for achieving such modulation. The first uses ion
bombardment of ferrimagnetic layered systems; and the second,
plasma oxidation of ferromagnetic layers. Both methods allow to
obtain layers with periodically varied properties without
topographical changes. This opens new ways to generate magnonic
crystals.
This work was supported by the National Science
Centre in Poland Sonata-Bis (DEC- 2015/18/E/ST3/00557) project. B.
A. acknowledges support from project No. POWR.03.02.00-00-I032/16
under the European Social Fund – Operational Programme Knowledge
Education Development, Axis III Higher Education for Economy and
Development, Action 3.2 PhD Programme.
Chair: Dr. Emerson Coy
Seminar language: English
/529/
Date: Thursday, 14 Nov 2019 at 9:40-10:00
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Bartłomiej Graczykowski
Authors: M. Kasprzak, M. Śledzińska, K. Zaleski, I. Iatsunskyi, S.
Volz, F. Alzina, C. M. Sotomayor Torres, and B. Graczykowski.
Affiliation of the presenting author: Faculty of Physics, Adam
Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań,
Poland
Title: Nanoscale silicon thermal diode and switch
Abstract: The recent research has pointed to nanostructuring as a
highly efficient approach to reducing thermal conductivity. One
example of nanostructured materials are porous/holey phononic
crystals (PnCs), which thermal conductivity can be engineered by
means of the surface-to-volume ratio and surface roughness.
Tuneable thermal properties make these structures good candidates
for integrated heat management devices, for instance for waste
heat recovery or heat rectification. In particular, the thermal
rectification means that the magnitude of heat flux changes when
the temperature gradient is reversed in direction. As a step
towards heat rectification using silicon porous membranes in this
work, we studied both thermal conductivity and its temperature
dependence on a geometric parameter, i.e. the surface-to-volume
ratio.
Chair: prof. Sławomir Mielcarek
Seminar language: English
/528/
Date: Thursday, 14 Nov 2019 at 10:05-10:20
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. N.K.P. Babu
Authors: N. K. P. Babu, A. Trzaskowska, S. Mielcarek, H.
Glowiński, P. Kuświk, F. Stobiecki, M. Zdunek, P. Graczyk, J. W.
Kłos, G. Centala, and M. Krawczyk
Affiliation of the presenting author: Faculty of Physics, Adam
Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań,
Poland
Title: Detection of magnon-phonon Interactions using BLS
spectroscopy in CoFeB/Au multilayer structure
Abstract: The investigations about the phenomena involving
interactions between thermal magnons and phonons have grate
interest in modern emerging field of spintronics. In our studies,
we determine the dispersion relation of thermal magnons and
phonons in the CoFeB/Au multilayer deposited on a silicon
substrate with Ti and Au buffer layers using Brillouin light
scattering spectroscopy. We choose two geometries oblique
geometry, (where the angle between magnetic field and wave vector
is 45°) and Backward volume geometry (where the magnetic field and
wave vector are perpendicular to each other). We found three
different types of spin waves (Backward volume mode (BV-SW),
perpendicular standing mode (PS-SW) and Damon-Eshbach mode
(DE-MSW) and two phonon modes (Rayleigh (R-SAW) and Sezawa
(S-SAW).
Chair: prof. Sławomir Mielcarek
Seminar language: English
/527/
Date: Thursday, 14 Nov 2019 at 10:25-10:40
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. Miłosz Zdunek
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Interaction between thermal magnons and phonons in
[Ni80Fe20/Au/Co/Au]10 multilayer
Abstract: We have investigated surface acoustic waves’ and spin
waves’ dispersion relations in [Ni80Fe20/Au/Co/Au]10 multilayers.
The method we used in our investigations was high resolution
Brillouin spectroscopy. The thickness of 0.8 nm has been chosen
for cobalt (Co) layer as it exhibits in-plane effective
anisotropy. It allowed us to gather spectra of spin waves for two
canonical geometries. In both cases spin wave’s wave vector lies
in the plane of our sample, the difference occurs with the
orientation of wave vector vs. static magnetization: in one
geometry those vectors are perpendicular (Damon-Eschbach spin
wave), while in the other they are parallel to each other
(Backward Volume spin wave). The main goal of our experiment was
to investigate the crossing regions of phononic ang magnonic
dispersion relations.
Chair: prof. Sławomir Mielcarek
Seminar language: English
/526/
Date: Thursday, 14 Nov 2019 at 10:45-11:00
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. O. M. Chumak
Affiliation of the presenting author: Institute of Physics, Polish
Academy of Sciences, Warsaw, Poland
Title: Strain Modulated Ferromagnetic Resonance technique and it’s
application for Co2YZ Heusler thin films investigation
Abstract: The unique Strain Modulated Ferromagnetic Resonance
(SMFMR) technique will be presented, which allows determination of
the magnetoelastic properties of thin magnetic films or ribbons,
viz. magnetoelastic constants of the material. The SMFMR technique
is successfully applied for investigation of thin layers of
Co2FexMn1−xSi (CFxM1−xS),
Co2Fe0.4Mn0.6Si (CFMS) and Co2FeGa0.5Ge0.5
(CFGG) Heusler alloys. The alloys mentioned above are
characterized by high spin polarization and are good candidates
for technical applications, among others in spintronics and
magnonics; the magnetoelastic properties, magnetic anisotropy and
dissipative properties play an important role in these materials.
Several effects are investigated: the effect of the magnetic layer
composition changing (CFxM1−xS), the finite thickness of
the magnetic layer and the use of various buffer and surface
layers (CFMS and CFGG). This work is partially supported by the
National Science Centre of Poland – project number
2018/31/B/ST7/04006.
Chair: prof. Sławomir Mielcarek
Seminar language: English
/525/
Date: Thursday, 14 Nov 2019 at 11:20-11:40
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Radosław Strzałka
Authors: Radosław Strzałka, Ireneusz Bugański, Janusz Wolny.
Affiliation of the presenting author:
Faculty of Physics and Applied Computer Science, AGH University of
Science and Technology, Kraków, Poland
Title: New approach to structural disorder in aperiodic systems –
example of decagonal AlCuRh quasicrystal
Abstract: An intriguing feature observed in modern refinements’
results of quasicrystals in the log-log plot of calculated vs.
observed intensities is a characteristic bias in the low-peaks
regime [e.g. 1,2]. The underestimation of the calculated
diffraction intensities is of an unknown origin so far. The two
possible reasons are most likely: (i) improper phasonic correction
conventionally used in the form of the exponential Debye-Waller
factor [3], and/or (ii) multiple scattering effect [4]. In our
previous studies based on the model calculations we showed that
the new correction for phasons developed within the statistical
approach is potentially useful to solve the problem of a bias [3].
The correction for phasons (understood as flips/rearrangement of
tiles in the quasiperiodic tiling) is made at the stage of the
structure factor calculation, and it assumes the fragmentation of
the probability distributions of atomic positions (called also the
average unit cell, AUC, which is a real-space equivalent of the
atomic surface/occupation domain in the hyperspace description,
more on the AUC method in [5]). The Fourier transform of the
“fragmented” (influenced by phason flips) AUC gives a diffraction
pattern affected by a phasonic disorder. The only parameter to fit
is a flip ratio (a probability of a single tile rearrangement in
the structure). We assume only two types of flips (in regions of
two thin and one thick, or two thick and one thin rhombuses, which
build a hexagon), the phason-phonon coupling and the secondary
phason flip effects are neglected. Recently we developed also a
phenomenological way of diffraction data treatment in terms of the
multiple scattering effect [6]. It is based on the Rossmanith
theory [7 and later works] and considers a redistribution of
intensities among all diffraction peaks with a given probability
(the probability parameter is to be fitted). The two corrections
are included in our refinement procedure developed within the
statistical method. In the presentation we will show the
application of new corrections to the diffraction data (with
different refinement strategies) for decagonal AlCuRh
quasicrystal, originally studied by Kuczera et al. [1]. The final
results are: the value of R-factor is 6in the original refinement) with phasonic ADP of 1.35A2, phason
flip probability of 1.34probability of 4.2×10-7. The results were published in [6].
[1] P. Kuczera, J. Wolny, W. Steurer, Acta Cryst. B 68, 578
(2012).
[2] H. Takakura, C.P Gomez, A. Yamamoto, M. de
Boissieu, A.P. Tsai, Nature Mater. 6, 58 (2007).
[3] J. Wolny,
I. Bugański, P. Kuczera, R. Strzałka, J. Appl. Cryst. 49, 2106
(2016).
[4] H. Takakura, R. Mizuno, Mater. Struct. 22, 281
(2015).
[5] R. Strzałka, I. Bugański, J. Wolny, Crystals 6,
104 (2016).
[6] I. Bugański, R. Strzałka, J. Wolny, Acta
Cryst. A 75, 352 (2019).
[7] E. Rossmanith, J. Appl. Cryst.
32, 355 (1999).
Chair: prof. Jarosław W. Kłos
Seminar language: English
/524/
Date: Thursday, 14 Nov 2019 at 11:45-12:00
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. Szymon Mieszczak
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Spin wave localization on phasonic defects in magnonic
quasicrystal
Abstract: Phasons are the structural defects that are specific for
quasicrystal. They are local rearrangements of the constituent
elements in the quasiperiodic structure. We investigated the
perturbed Fibonacci sequences of stripes with lower concentrations
of phasonic defects. The goal of this study is to find the impact
of the phasonic-like disorder on the spectrum and the localization
of spin wave eigenmodes in magnonic quasicrystals.
The
authors acknowledge the financial support of the National Science
Centre Poland for Grant No. 2016/21/B/ST3/00452 and
UMO-2017/24/T/ST3/00173.
Chair: prof. Jarosław W. Kłos
Seminar language: English
/523/
Date: Thursday, 14 Nov 2019 at 13:35-13:55
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Dr. Gabriel Chaves-O’Flynn
Authors: Daniel L Stein, Andrew D Kent, and Gabriel
Chaves-O’Flynn.
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Activation Barriers for Creation and Annihilation of
Magnetic Droplet Solitons
Abstract: Droplet solitons are magnetization fluctuations that
preserve their shape as they precess with uniform frequency. We
introduce an effective energy ξ that quantifies the work done
(against damping and spin torque) to create a fluctuation of
arbitrary shape θ(ρ). We show that, for specific values
of σ, some soliton solutions are saddles of ξ. This
allows us to calculate thermal activation barriers ∆ξ
between uniform precession at the ferromagnetic resonance and
stable solitons. We present results of ∆ξ as a function
of σ for a variety of nanocontact radii ρ*.
Chair: prof. Piotr Zieliński
Seminar language: English
/522/
Date: Thursday, 14 Nov 2019 at 14:00-14:15
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. Mateusz Zelent
Authors: S. Saha, M. Zelent, J. Feilhauer, J. Tobik, S. Finizio,
M. Mruczkiewicz, S. Tacchi, A. K. Suszka, S. Wintz, N. S. Bingham,
J. Raabe, M. Krawczyk, And L. J. Heyderman.
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Formation and driving by electric current of Neel-type
skyrmion in antidot lattices
Abstract: Magnetic skyrmions are topologically protected
nano-meter sized chiral spin textures. Due to their various unique
features, such as stability given by their topology, they are
considered as potential candidates for information carriers in
next generation data storage devices, like racetrack memory.
Therefore, it is crucial to be able to manipulate their
current-induced motion. We extend the idea to control motion of
skyrmion in 2D plane with the in plane electric current pulses.
This goal we have achieved through the use of magnetic antidot
arrays. We have demonstrated experimentally that magnetic
skyrmions can stabilize in a magnetic antidot array based on
Ta/Co/Pt multilayers. Moreover with micromagnetic simulations we
show that in such an antidot array the skyrmions can be guided in
different directions. Depending on both, the size of the antidots
and the current density, different types of skyrmion motion on the
film plane were found, also the one shown in figure. Thus,
magnetic antidot arrays can be used as a controller for skyrmion
motion by using properly designed sequences of electrical current
pulses, which makes them a promising candidate for current driven
skyrmion motion control.
Chair: prof. Piotr Zieliński
Seminar language: English
/521/
Date: Thursday, 14 Nov 2019 at 14:20-14:35
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: M.Sc. Krzysztof Szulc
Authors: K. Szulc, M. Mruczkiewicz, P. Graczyk, G. Gubbiotti, and
M. Krawczyk.
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Spin-wave diode and circulator
Abstract: We propose a model of spin-wave diode which is based on
the effect of unidirectional coupling of spin waves in wide
frequency range in bilayered ferromagnetic system. This effect
bases on Dzyaloshinskii-Moriya interaction and dipolar coupling.
Our spin-wave diode consists of ferromagnetic stripe lying above
the ferromagnetic layer. Unidirectional coupling permits spin
waves to transfer to the stripe when propagating in coupling
direction, while in non-coupling direction the spin-wave transfer
is very weak. Structure with additional layer coupled with the
stripe can be proposed as a spin-wave circulator.
Chair: Prof. Piotr Zieliński
Seminar language: English
/520/
Date: Thursday, 14 Nov 2019 at 14:40-15:00
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Maciej Krawczyk
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Spin wave dynamics in complex magnetization textures
Abstract: We study spin wave dynamics in thin films with
perpendicular magnetic anisotropy patterned with a square lattice
of antidots. We show reach spin-wave spectra at remanence which
indicates the non-collinear magnetization states around the
antidots. The obtained results of spin-wave dynamics in these thin
films with complex, but periodic magnetization textures, allow as
to point out features promising for new phenomena in magnonics and
their potential usefulness for applications.
Chair: Prof. Piotr Zieliński
Seminar language: English
/519/
Date: Thursday, 14 Nov 2019 at 15:20-15:40
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Piotr Tomczak
Authors: Piotr Tomczak and Henryk Puszkarski.
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Spin wave dynamics in complex magnetization textures
Abstract: One of the main goals of performing FMR experiments is
to find how the magnetic energy of a sample under investigation
depends on magnetic field direction with respect to a sample
crystallographic axes. This information is usually obtained by
examining the experimental dependence of the resonance field value
on its direction in space. The traditional analysis of
experimental data is carried out using the well-known Kittel or
Smit-Beljers equations describing the precessional motion of the
sample magnetization.
We propose [1] a new FMR data analysis method by referring to the
geometric meaning of the Smit-Beljers equation: the resonance
frequency of the magnetic moment precessional motion is equal to
the Gaussian curvature of the spatial distribution of the magnetic
free energy. This approach allows finding all the values of
relevant physical quantities with high accuracy (the saturation
magnetization M, g-factor, demagnetizing tensor
Nαβ and magnetocrystalline anisotropy constants
Kα) and consequently the spatial distribution of the free
energy from a single set of FMR experimental data.
We tested successfully [1] this approach using the
cross-validation procedure [2] for bulk magnetite, (Ga,Mn)As thin
film, YIG ultrathin film, Co ultrathin film and Fe thin film.
Note, that it was necessary while doing the cross-validation, to
use a proper form of the free energy dependence on all above
mentioned magnetic parameters characterizing the sample of each
ferromagnet under investigation. Therefore, the criterion of the
correctness of the free energy formulas given in [2] was also
applied in this work. Let us emphasize that none of the known
methods of analysis of
FMR experiments does give such universal opportunities.
Acknowledgments
Supported by NCN grant No. DEC-2013/08/M/ST3/00967.
References
[1] P. Tomczak and H. Puszkarski, arXiv:1901.01207.
[2] P. Tomczak and H. Puszkarski, Phys. Rev. B 98, 144415
(2018).
Chair: Dr. Andrzej Janutka
Seminar language: English
/518/
Date: Thursday, 14 Nov 2019 at 15:45-16:05
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Sławomir Mamica
Affiliation of the presenting author: Faculty of Physics, Adam
Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań,
Poland
Title: Nonuniform softening of spin waves in 2D magnonic crystals
Abstract: In thin-film bicomponent magnonic crystals (MCs) an
in-plane magnetization causes the demagnetizing field to occur
around interfaces between constituent materials. The field has a
great impact on the spin-wave spectrum, e.g. in cobalt-permalloy
MCs at the low external magnetic field the lowest-frequency spin
waves are excited in Co much more likely than in Py regardless the
matrix or rods are made from Co. As a consequence the nonuniform
softening of spin waves takes place. We show it could be very
useful mechanism to design complete magnonic gaps with different
sensitivity for the tiny change of the external field.
[1]
S. Mamica, M. Krawczyk, and D. Grundler, Non-uniform spin wave
softening in 2D magnonic crystals as a tool for opening
omnidirectional magnonic band gaps, Phys. Rev. Applied 11, 054011
(2019). arXiv: 1810.04005
[2] S. Mamica and M. Krawczyk,
Reversible tuning of omnidirectional band gaps in two-dimensional
magnonic crystals by the low magnetic field, (2019),
arXiv:1906.07469
Chair: Dr. Andrzej Janutka
Seminar language: English
/517/
Date: Thursday, 14 Nov 2019 at 16:10-16:30
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Piotr Zieliński
Authors: D. Kuzma, J. Kłos, J. Rychły, S. Mieszczak, P.
Sobieszczyk, and P. Zieliński.
Affiliation of the presenting author:
Institute of Nuclear Physics, Polish Academy of Sciences, ul.
Radzikowskiego 152, 31-342 Kraków, Poland
Title: Static configurations and spin wave dynamics in finite
magnetic chains: from simplified models to micromagnetic
calculations
Abstract: Any defect of periodicity is a potential localization of
one or several bound modes. They differ from the bulk modes in
that their wave functions decay exponentially with the distance
from the defect in contrast with bulk mode showing a Bloch
oscillatory behavior typical of propagative waves. In this note we
study possibilities of existence of end bound (edge) modes in 1d
systems of macrospins of selected shapes and test validity of some
simplified models in the description of the lowest frequency range
dynamics in such systems. The simplest possible model by Stoner
and Wohlfarth assumes the whole magnetic moment of the macrospin
concentrated in one point. The dipolar interactions are, thus,
very strong. The configurations of finite magnetic chains obtained
with this model are very interesting in that they show a number of
tilted structures as a function of a magnetic field perpendicular
to the chain. More developed model involves long 1D thin threads
or wires. We have found a simple analytic expression for the
dipolar interactions in such threads. The latter model reproduces
fairly well the lowest excitations in the finite chains of
macrospins with, however, selected geometries. We will discuss the
validity of the models and the best physical realization of bound
states in the finite chains.
Chair: Dr. Andrzej Janutka
Seminar language: English
/516/
Date: Thursday, 14 Nov 2019 at 16:35-16:55
Conference: QuTecNOMM 2019 - Session on Magnonics and Metamaterials
Speaker: Prof. Tadeusz Lulek
Affiliation of the presenting author:
Faculty of Physics, Adam Mickiewicz University, Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
Title: Algebraic Bethe Ansatz as a tool for quantum information
processing
Abstract: Algebraic Bethe Ansatz (ABA), known as the way of
expressing a unique exact result of a quantum onedimensional
N-body problem – the eigenproblem of the Heisenberg Hamiltonian
for the chain of N spins 1/2 , can be also seen as a tool for
various operations with systems of qubits, prepared in highly
correlated multiparticle states with precisely prescribed
properties. As a rule, one uses ABA in its off-diagonal version,
in order to create single-magnon states with rapidities resulting
from Bethe Ansatz equations – a system of r highly nonlinear
algebraic equations which yields exact eigenstates of an
integrable model. Here, we advocate for the diagonal version of
ABA, namely for an immediate solution of (roughly) N spectral
problems for constants of motion, generated from the transfer
matrix – the trace of the monodromy matrix. The resulting system
of constants of motion provides a realisation of a positive
operator-valued measure (POVM), that is, a complete set of
commuting operators along the prescripyion of Dirac. The program
can be computationally realised only for a small number N of
qubits, but it might be pretty practical for typical procedures
carried by Alice and Bob.
Chair: Dr. Andrzej Janutka
Seminar language: English
/515/
Date: Wednesday 2019.10.23 at 14:25-14:40
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Mateusz Nowotarski
Affiliation: Quantum Optics and Engineering Division, Institute of
Physics, University of Zielona Góra, Zielona Góra, Poland
Title: Frequency of violation of Bell-type inequalities as a
quantifier of nonlocality
Authors: Artur Barasiński (1,2), Antonín Černoch (2), Karel Lemr
(2), and Jan Soubusta (2)
Addresses:
(1) Institute of Physics, University of Zielona Góra, Poland
(2) Joint Laboratory of Optics of Palacky University and Institute
of Physics of Czech Academy of Sciences, 771 46 Olomouc, Czech
Republic
Abstract: Motivated by the proposal for quantification of Bell
nonlocality [2], we present our results of the analysis of this
concept, namely, the volume of violation. This new measure of
nonlocality has been proposed to prove that the anomaly between
maximally entangled states and states that maximally violate Bell
inequality is caused by the method of quantifying nonlocality
itself, and such anomaly disappears when the volume of violation
is applied. We prove that this is not the case for all bipartite
quantum systems with dimension d×d [1].
[1] Artur Barasiński, Mateusz Nowotarski Phys.Rev. A 98, 022132
(2018)
[2] E. A. Fonseca, Fernando Parisio Phys.Rev. A 92,
030101 (2015)
Chair: Prof. Zbigniew Ficek
Seminar language: English
/514/
Date: Wednesday 2019.10.23 at 14:10-14:25
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Izabela Domagalska
Title: Thermodynamic properties of superconductivity - the
numerical and semi-analytical approaches
Authors: I. A. Domagalska (1), E. A. Drzazga–Szczęśniak (2), M. W.
Jarosik (2), R. Szczęśniak (2), J. K. Kalaga (1)
Addresses:
(1) Quantum Optics and Engineering Division, Institute of Physics,
University of Zielona Góra, Zielona Góra, Poland
(2) Institute of Physics, Częstochowa University of Technology,
Częstochowa, Poland
Abstract: Despite the relatively large electron-phonon coupling
constant for vanadium, the quantities such as the order parameter,
the specific heat, and the thermodynamic critical field determine
the values of the dimensionless ratios not deviating much from the
predictions of the BCS theory. This result is associated with the
reduction of the strong-coupling and the retardation effects by
the high value of the Coulomb pseudopotential. It has been shown
that the results of the Eliashberg formalism can be relatively
precisely reproduced with the help of the semi-analytical
formulas, if the value of μ is determined on the basis of the
Tc-Allen-Dynes expression. The attention should be paid to the
fact that in the numerical and in the semi-analytical approach the
comparable values of the thermodynamic parameters for the same
μ have been obtained only in the vicinity of the point.
Chair: Prof. Zbigniew Ficek
Seminar language: English
/513/
Date: Wednesday 2019.10.23 at 13:50-14:10
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Dr. Joanna Kalaga (invited speaker)
Affiliation: Quantum Optics and Engineering Division, Institute of
Physics, University of Zielona Góra, Zielona Góra, Poland
Title: Entanglement generation in system of two coupled nonlinear
oscillators
Abstract: The system ability to produce maximally or almost
maximally entangled states is important for the development of
quantum information theory and its applications. Such states are
necessary for quantum communication, quantum cryptography or
quantum calculations. As a source of maximally entangled states
will be considered the system consisting of two coupled nonlinear
oscillators excited by a series of ultra-short coherent pulses.
For such a system the influence of various excitation methods on
the efficiency of generation maximally entangled states will be
discussed.
Chair: Prof. Zbigniew Ficek
Seminar language: English
/512/
Date: Wednesday 2019.10.23 at 13:35-13:50
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Dr. Huan-Yu Ku (invited speaker)
Affiliation: Department of Physics and National Center for
Theoretical Sciences, National Cheng-Kung University, Tainan 701,
Taiwan
Title: Quantum computations on IBM Q: Experimental test of
non-macrorealistic cat states in the cloud
A quantum witness attempts to classify observations or
experimental outcomes as arising from one of two possible classes
of physical theories: those described by macrorealism, and those
that are not (e.g., quantum theory). While many notions of what
makes something macroscopic exist, here we take a practical
approach of increasing the number of qubits contributing to the
witness, and maximizing the `disconnectivity' (in the form of the
entanglement) between said qubits. In this regard we
experimentally implement a quantum witness on a set of small cat
states (two-qubit entangled states) and large cat states (GHZ
states with qubit number n = 4 and 6) using the IBM quantum
experience.Our results show that the small cat states and
four-qubit GHZ state are non-macrorealistic. In contrast, a
six-qubit GHZ state does not violate the witness beyond a so
called measurement invasiveness test, and thus might be understood
in macrorealistic terms. As a comparison, we also consider
un-entangled superposition states with n = 2, 3, 4, and 6
qubits, in which the disconnectivity is low.
Chair: Prof. Yueh-Nan Chen
Seminar language: English
/511/
Date: Wednesday 2019.10.23 at 13:20-13:35
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Dr. Jhen-Dong Lin (invited speaker)
Affiliation: Department of Physics and National Center for
Theoretical Sciences, National Cheng-Kung University, Tainan 701,
Taiwan
Title: Quantifying quantum scrambling with temporal quantum
steering
Abstract: Quantum information scrambling describes the
delocalization of local information to entanglement throughout all
possible degrees of freedom. A well-known scrambling witness is
the so-called out-of-time-ordered correllator (OTOC). The
important insight of OTOC is that it is closely related to the
incompatibility of two separate operators at two different times.
In this work, we show that quantum scrambling can be witnessed in
the context of temporal quantum steering. The essential point
relies on the connection between Choi-Jamiolkowski isomorphism and
the pseudo-density matrix formalism used in temporal quantum
correlations. Based on this relation, we propose a scrambling
quantifier, −T3, according to an extended temporal steering
scenario. We prove that −T3 is monogamous, and when the channel
is non-interacting (non-scrambled), −T3=0.
Chair: Prof. Yueh-Nan Chen
Seminar language: English
/510/
Date: Wednesday 2019.10.23 at 13:00-13:20
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Wiesław Leoński (invited speaker)
Affiliation: Quantum Optics and Engineering Division, Institute of
Physics, University of Zielona Góra, Zielona Góra, Poland
Title: Quantum steering and its transfer along the chains of
nonlinear oscillators
Chair: Prof. Yueh-Nan Chen
Seminar language: English
/509/
Date: Wednesday 2019.10.23 at 11:40-12:00
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. dr. Zbigniew Ficek (invited talk)
Affiliation: Quantum Optics and Engineering Division, Institute of
Physics, University of Zielona Góra, Zielona Góra
Title: Phase control of entanglement and quantum steering in a
three-mode optomechanical system
Abstract: The phase control of coherence, entanglement and
quantum steering will be discussed for an optomechanical system
composed of a single mode cavity containing a partially
transmitting dielectric membrane and driven by short laser pulses.
The membrane divides the cavity into two mutually coupled
optomechanical cavities resulting in an effective three-mode
closed loop system, two field modes of the two cavities and a
mechanical mode representing the oscillating membrane. The closed
loop in the coupling creates interfering channels which depend on
the relative phase of the coupling strengths of the field modes to
the mechanical mode. For example, populations and correlations of
the output modes show several interesting phase dependent effects
such as reversible population transfer from one field mode to the
other, creation of collective modes, and induced coherence without
induced emission. The inseparability criterion for the output
modes will be also investigated and we will show that entanglement
may occur only between the field modes and the mechanical mode. We
find that depending on the phase, the field modes can act on the
mechanical mode collectively or individually resulting,
respectively, in tripartite or bipartite entanglement. In
addition, we will examine the phase sensitivity of quantum
steering of the mechanical mode by the field modes. Deterministic
phase transfer of the steering from bipartite to collective is
predicted and optimum steering corresponding to perfect EPR state
can be achieved.
Chair: Prof. Wiesław Leoński
Seminar language: English
/508/
Date: Wednesday 2019.10.23 at 11:20-11:40
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Yueh-Nan Chen (invited talk)
Affiliation: Department of Physics and National Center for
Theoretical Sciences, National Cheng-Kung University, Tainan 701,
Taiwan
Title: Temporal quantum steering
Abstract: Quantum steering is the ability to remotely prepare
different quantum states by using entangled pairs as a resource.
In this talk, I will introduce a natural temporal analog of the
EPR steering when considering measurements on a single object at
different times. I will also give nontrivial operational meaning
to violations of the temporal steering inequality by showing that
it is connected to the security bound in the Bennett-Brassard 1984
protocol. Moreover, I will show that the temporal steering can be
measured, via semidefinite programing, with a temporal steerable
weight, in direct analogy to the proposed EPR steerable weight.
Finally, I will demonstrate that the temporal steering can be
experimentally verified on IBM Q.
Chair: Prof. Wiesław Leoński
Seminar language: English
/507/
Date: Wednesday 2019.10.23 at 11:00-11:20
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Ryszard Tanaś (invited talk)
Affiliation: Nonlinear Optics Division, Physics Faculty, Adam
Mickiewicz University, Poznań, Poland
Title: Collective nonclassical effects in a three-atom system
Abstract: Multi-qubits systems can exhibit various correlations,
classical and quantum, which are subject of intensive studies.
Quantum correlations in multi-qubit systems are subject of
intensive studies. Probably the most popular measure of quantum
correlations is entanglement, but there are other measures that
have been introduced and studied, such as quantum discord,
geometric quantum discord, measurement induced disturbance and
others. The simplest bipartite system in which the correlations
can be studied is a system of two qubits, or two two-level atoms.
In case of two-level atoms interacting with the reservoir of
electromagnetic field modes in the vacuum, the evolution of the
system can be described by the well known Lehmberg-Agarwal master
equations. The collective evolution of the two-atom system depends
on two collective parameters: collective damping 12 and
dipole-dipole interaction 12, which both depend on the interatomic
distance. Such a system is a good testing ground for studying
evolution of quantum correlations. In my talk, I want to give some
results dealing with collective effects in a system of three-
atoms. Such a system is more difficult to describe because, for
mixed states, we deal with 8×8 matrix which leads to 63
equations, and, what is even worse, there are no formulas to
calculate concurrence, even if we know all the matrix elements.
However, if we forget about damping, The Hamiltonian of the system
can be diagonalized leading to pure eigenstates of the system
including the dipole-dipole interaction. It is possible to
calculate concurrence and negativity for such states, which gives
some information on collective effects in the system. When the
collective damping is included, evolution of the system is
governed by the ma- ster equation which can be solved numerically
for the matrix elements of the density matrix (analytical solution
is possible but it is too complicated to be useful). It allows to
calculate evolution of the negativity for different initial
states. We have found, in particular, the so called monogamy
relations for negativity, for chosen initial states of the system.
It was shown that for some initial states the monogamy relations
are violated.
Chair: Prof. Wiesław Leoński
/506/
Date: Tuesday 2019.10.15 at 13:30-13:45
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Shilan Ismael Abo
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Unconventional multiphoton blockade
Chair: Prof. Adam Miranowicz
Seminar language: English
/505/
Date: Friday 2019.10.18 at 13:00-13:30
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Jan Peřina Jr. (invited speaker)
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of the Czech Academy of Sciences, Faculty
of Science, Palacký University, Olomouc, Czech Republic
Title: Waves in spatio-spectral and -temporal coherence of
evolving ultra-intense twin beams
Abstract: Waves in the spatio-spectral and -temporal coherence of
evolving ultra-intense twin beams are predicted [1]: Twin beams
with low intensities attain maximal coherence in the beam center
until certain threshold intensity is reached. Then the area of
maximal coherence moves with increasing intensity from the beam
center towards its edges leaving the beam center with low
coherence (the first coherence wave). For even larger intensities,
a new coherence maximum is gradually built in the beam center with
the increasing intensity [2] and, later, it again moves towards
the beam edges forming the second coherence wave.
Rotationally-symmetric twin beams are analyzed within a
three-dimensional model that couples spectral and spatial degrees
of freedom. Relation between the twin-beam coherence and its local
density of modes during the nonlinear evolution is discussed.
[1] J. Perina Jr.: Waves in spatio-spectral and -temporal
coherence of evolving ultra-intense twin beams, Sci.
Rep. 9, 4256 (2019).
[2] J. Perina Jr.: Spatial, spectral and temporal coherence of
ultra-intense twin beams, Phys. Rev. A 93, 013852 (2016).
Chair: Prof. Adam Miranowicz
Seminar language: English
/504/
Date: Tuesday 2019.10.15 at 15:20-15:40
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Dr. Antonin Černoch (invited speaker)
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Olomouc, Czech Republic
Title: Interferometers in the service of quantum information
processing
Abstract: Interferometer is a complex device frequently used in
experimental proof-of-principle setups for research using optical
methods. In this talk several constructions will be presented and
basic parameters discussed in the context of our recent research.
Chair: Prof. Jan Soubusta
Seminar language: English
/503/
Date: Tuesday 2019.10.15 at 15:05-15:20
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Kateřina Jiráková
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Olomouc, Czech Republic
Title: Experimental implementation of a machine-learned quantum
gate
Abstract: The talk will focus on experimental implementation of a
machine-learned quantum gate. The goal was to learn the gate to
perform optimal phase-covariant cloning by means of reinforcement
learning. This experiment demonstrates present-day feasibility and
practical applicability of the hybrid machine learning approach.
Chair: Prof. Jan Soubusta
Seminar language: English
/502/
Date: Tuesday 2019.10.15 at 14:50-15:05
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Jan Roik
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Olomouc, Czech Republic
Title: Comparison of three experimental approaches to weak value
estimation
Abstract: Weak values are traditionally obtained using a weak
interaction between the measured system and a pointer state. It
has, however, been pointed out that weak coupling can be replaced
by a carefully tailored strong interaction. This talk is about a
direct comparison of two strong interaction-based approaches
(strong interaction accompanied by either a suitably prepared
pointer state or quantum erasure) and the traditional weak
interaction-based method on the platform of linear optics.
Chair: Prof. Jan Soubusta
Seminar language: English
/501/
Date: Tuesday 2019.10.15 at 14:30-14:50
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Karol Bartkiewicz
Affiliations: (1) Nonlinear Optics Division, Physics Faculty, AMU,
Poznań and (2) RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Faculty of Science, Palacký University, Czech
Republic
Title: Kernel based quantum machine learning with photons
Abstract: Is it possible to implement practical quantum machine
learning? Here we answer this question by implementing first
all-optical setup that implements a kernel-based supervised
quantum machine learning for three standard two-dimensional
classification problems. In contrast to distance-based quantum
machine learning, we need only to perform projective measurements
on specially designed quantum states that efficiently encode the
training data set. Our experiment is a two-photon implementation
of a recent proposal of Schuld and Killoran [Phys. Rev. Lett. 122
040504 (2019)], where instead of continuous variables we implement
variable spread kernels by varying the number of photons used in
feature mapping circuit.
Chair: Prof. Jan Soubusta
Seminar language: English
/500/
Date: Tuesday 2019.10.15 at 12:10-12:30
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Rafał Demkowicz-Dobrzański (invited speaker)
Affiliation: Faculty of Physics, University of Warsaw
Title: The great unified theory of quantum metrology
Abstract: A general model of unitary parameter estimation in
presence of Markovian noise is considered, where the parameter to
be estimated is associated with the Hamiltonian part of the
dynamics. In absence of noise, unitary parameter can be estimated
with precision scaling as 1/T, where T is the total probing
time. A simple algebraic condition involving solely the operators
appearing in the quantum Master equation, decides whether 1/T or
1/√T scaling of precision is achievable using the most
general adaptive quantum estimation strategies including quantum
error-correction protocols.
Chair: Prof. Karel Lemr
Seminar language: English
/499/
Date: Tuesday 2019.10.15 at 11:50-12:10
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Paweł Kurzyński
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Contextuality of identical particles
Abstract: Contextuality is a more general notion than nonlocality,
since it also applies to measurements done in a single laboratory
on a local system. In majority of scenarios one considers
measurements done on a single particle and there are many proofs
showing that these measurements do not admit a classical
description in terms of noncontextual hidden-variable theories.
However, the situation might be different if one performs
collective measurements on many particles. In particular, what
happens if one considers many indistinguishable particles? I am
going to show that indistinguishability affects our ability to
observe contextuality. Moreover, I will show that this approach
allows one to resolve the problem of Bell inequality violations
with classical light.
[1] "Contextuality of identical particles", P. Kurzyński, Phys.
Rev. A 95, 012133 (2017)
[2] "From contextuality of a single
photon to realism of an electromagnetic wave", M. Markiewicz, D.
Kaszlikowski, P. Kurzyński, A. Wójcik, npj Quantum Information 5,
5 (2019).
Chair: Prof. Karel Lemr
Seminar language: English
/498/
Date: Tuesday 2019.10.15 at 11:35-11:50
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Marcin Karczewski
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Generating entanglement with single-photon subtractions
Abstract: The states of a system of identical particles are
required to be symmetric for bosons and antisymmetric for
fermions. Are these inherent correlations just a mathematical
artifact or can they be treated as a resource? In the talk I will
support the latter point of view by showing how operationally
accessible entanglement can be extracted form the
indistinguishability of particles. I will focus on a recently
proposed method [1] based on tailored single-photon subtractions
from multiboson states.
[1] M. Karczewski et al., "Sculpting
out quantum correlations with bosonic subtraction." Phys. Rev. A
100, 033828 (2019).
Chair: Prof. Karel Lemr
Seminar language: English
/497/
Date: Tuesday 2019.10.15 at 11:20-11:35
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Zakarya Lasmar
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: When can many fermions exhibit bosonic behaviour?
Abstract: A many-body system made of an even number of fermionic
constituents can collectively behave in a bosonic way. The
simplest example of such systems is the one made of two fermions.
In fact, this is example was heavily studied so far, and it is
unanimously accepted that entanglement plays a crucial role behind
the bosonic quality of its collective behaviour. However, if we
consider four fermions, they can behave like two bipartite bosons
or further assemble into a single four-partite bosonic molecule.
In general, 2N fermions can take many possible arrangements which
might be treated as composite bosons. In this talk, I will aim to
answer the question: what determines which fermionic arrangement
is going to be realized in a given situation and can such
arrangement be considered truly bosonic? I will discuss an
entanglement-based method to assess bosonic quality of fermionic
arrangements and apply it to study how the ground state of the
extended one-dimensional Hubbard model changes as the strength of
intra-particle interactions increases.
Ässembly of 2N
entangled fermions into multipartite composite bosons" Zakarya
Lasmar, P. Alexander Bouvrie, Adam S. Sajna, Malte C. Tichy, and
Paweł Kurzyński Phys. Rev. A 100, 032105 (2019)
Chair: Prof. Karel Lemr
Seminar language: English
/496/
Date: Tuesday 2019.10.15 at 10:45-11:00
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Vojtěch Trávníček
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Olomouc, Czech Republic
Title: Experimental measurement of Hilbert-Schmidt distance
Abstract: The talk touches on the definition of Hilbert-Schmidt
distance and its translation to measurable observables. Further it
discusses the experimental implementation on the platform of
linear optics. The reasons and benefits of measuring the
Hilbert-Schmidt distance.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/495/
Date: Tuesday 2019.10.15 at 10:25-10:45
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Jan Soubusta (invited speaker)
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Olomouc, Czech Republic
Title: New experimental tests of three-qubit nonlocality
Abstract: We use our experimental setup, which is capable to
generate three-qubit GHZ states with high repetition rate. With
this setup we decided to test Hardy's paradox and to measure
nonlocal volume of the generated GHZ states.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/494/
Date: Tuesday 2019.10.15 at 10:05-10:25
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Dr. Grzegorz Chimczak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Two-photon blockade via interaction with a nonlinear
reservoir
Abstract: Recently, the group led by Gerhard Rempe has
demonstrated experimentally two-photon blockade in a driven
nonlinear system (composed of a harmonic cavity with a driven
atom). Inspired by this experiment, we show that two-photon
blockade can be generated in a driven harmonic cavity without an
atom or any other kind of nonlinearity, but instead coupled to a
nonlinear reservoir. We also investigate the possibility of
generating other nonstandard types of photon-blockade and
photon-induced tunneling.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/493/
Date: Tuesday 2019.10.15 at 9:45-10:05
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Karel Lemr (invited speaker)
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Olomouc, Czech Republic
Title: Experimental implementation of a programmable
controlled-phase gate (work in progress)
Abstract: The talk presents the concept of a programmable
controlled-phase gate and its linear-optical scheme. Usefulness of
this gate is discussed in the context of quantum machine learning
and quantum communications. Finally, the talk briefly outlines the
currently ongoing experimental implementation of this gate on the
platform of linear optics.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/492/
Date: Tuesday 2019.10.15 at 9:30-9:45
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: M.Sc. Vishal Vashistha
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: 4f system design and performing spatial filtering using
independent amplitude and phase control metasurfaces
Abstract: Metasurfaces based devices are widely in fashion and
metasurface become one of the promising platforms for photonics
devices. It has been explored for various photonics applications
such as light guiding, color filter design [1, 3]. Current
research based on metasurfaces is mostly dependent upon either
independent amplitude control or independent phase control
mechanism. To explore the further capability of metasurfaces, it
is important to have independent and simultaneous control on
amplitude, phase, polarisation, and, the optical impedance of the
wave [2]. In this talk, I am going to explain about independent
amplitude and independent phase control of metasurfaces based on
Pancharatnam-Berry (PB) phase mechanism. The technique is used to
design the complete 4f system based on metasurface for parallel
computing especially, spatial filtering purposes. It has high
potential to design the neural network front-end to performed fast
and parallel convolution
operation which is difficult and time-consuming in the electronic domain platform.
[1] Patrice Genevet, Federico Capasso, Francesco Aieta,
Mohammadreza Khorasaninejad, and Robert Devlin. Recent advances in
planar optics: from plasmonic to dielectric metasurfaces.
Optica, 4(1):139–152, 2017.
[2] Adam C Overvig, Sajan Shrestha, Stephanie C Malek, Ming Lu,
Aarton Stein, Changxi Zheng, and Nanfang Yu. Dielectric
metasurfaces for complete and independent control of optical
amplitude and phase. arXiv preprint arXiv:1903.00578, 2019.
[3] Vishal Vashistha, Gayatri Vaidya, Ravi S Hegde, Andriy E
Serebryannikov, Nicolas Bonod, and Maciej Krawczyk. All-dielectric
metasurfaces based on cross-shaped resonators for color pixels
with extended gamut. ACS photonics, 4(5):1076–1082, 2017.
Seminar language: English
/491/
Date: Tuesday 2019.10.15 at 9:10-9:30
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Igor L. Lyubchanskii (invited speaker)
Title: One-dimensional multiperiodic photonic structures: a new
route in photonics (four-component media)
Authors: I. S. Panyaev (1), L. R. Yafarova (1), D. G. Sannikov
(1), N. N. Dadoenkova (1), Y. S. Dadoenkova (2,1), and I. L.
Lyubchanskii (3,4)
Addresses:
(1) Ulyanovsk State University, Ulyanovsk, Russia
(2) Lab-STICC (UMR 6285), CNRS, ENIB, 29238 Brest Cedex 3,
France
(3) Donetsk Institute for Physics and Engineering of the
National
Academy of Sciences of Ukraine
(4) V. N. Karazin Kharkiv National University, 61022 Kharkiv,
Ukraine
Abstract: We study the transmittivity spectra of one-dimensional
finite three-periodic photonic crystals of the structure
[(ab)N(cd)M]K composed of four different layers a, b, c, d
being dielectric oxides Al2O3, SiO2, TiO2, and
ZrO2. We analyze modification of the transmittivity spectra of
near-infrared electromagnetic waves of the TE and TM polarizations
in the vicinity of the photonic band gaps with variations of the
sub-cell numbers N and M and super-cell number K, the
incidence angle, and the order of the layers in the structure. We
propose classification of three-periodic photonic crystals by the
magnitude and sign of the optical contrast between the layers in
pairs (ab) and (cd) forming the sub-cells and discuss common
spectral properties as well as their differences in these
structures [1].
[1] I. S. Panyaev, L. R. Yafarova, D. G. Sannikov, N. N.
Dadoenkova, Y. S. Dadoenkova, and I. L. Lyubchanskii. J. Appl.
Phys. 126 , 103102 (2019).
Chair: Prof. Jarosław Kłos
Seminar language: English
/490/
Date: Tuesday 2019.10.15 at 9:00-9:10
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Prof. Adam Miranowicz
Title: Symposium Opening and Welcome Note
/489/
Date: Wednesday 2019.10.09 at 13:00
Conference: QuTecNOMM 2019 - Session on Quantum Technologies
Speaker: Dr. Thomas B. Bahder (invited speaker)
Affiliation: Program Manager, Army Research Office 7-23-17
Roppongi, Minato-ku Tokyo 106-0032 Japan
Title: Topological Quantum Sensors?
Abstract: I will review the theory of "conventional" quantum
sensors as quantum channels of information between the quantity
(classical field) to be sensed and the measurement outcomes. The
Shannon mutual information and the Fisher information may be used
as metrics for the quality of a quantum sensor [1]. Next, I will
briefly describe non-ideal quantum sensors, which perform
non-unitary transformations on the input quantum state. The theory
of non-ideal quantum sensors is relevant to experiments because
the input quantum state may have errors, there may be scattering
(decoherence and dispersion) in the quantum channel, and the
output state detectors may not be ideal [2,3].
Next, I will introduce simple 1-qubit and 2-qubit models of a quantum sensor that have an analogy with topological energy band theory [4]. In preparation, I review some topological concepts such as Berry curvature and the Quantum Geometric Tensor. I will suggest that a new class of quantum sensors called "topological quantum sensors" may be realizable. Finally, I will give a detailed example of a topological quantum sensor of magnetic fields based on the dynamical quantum Hall effect [5].
1. T. B. Bahder and P. A. Lopata, "Fidelity of quantum interferometers", Rev. A 74, 051801(R) (2006).
2. D. S. Simon, A. V. Sergienko, and T. B. Bahder, “Dispersion and fidelity in quantum interferometry”, Phys. Rev. A 78, 053829 (2008).
3. T. B. Bahder, “Phase estimation with nonunitary interferometers: Information as a metric’’, Phys. Rev. A 83, 053601 (2011).
4. A. Bansil, H. Lin, and T. Das, "Colloquium: Topological Band Theory", Rev. Mod. Phys. 88, 021004 (2016).
5. V. Gritsev and A. Polkovnikov, PNAS (Proceedings of the
National Academy of Sciences U. S.) 109, 6457 (2012).
Chair: Prof. Adam Miranowicz
Seminar language: English
/488/
Date: Tuesday 2019.10.08 at 13:00
Speaker: Dr. Thomas B. Bahder
Affiliation: Program Manager, Army Research Office 7-23-17
Roppongi, Minato-ku Tokyo 106-0032 Japan
Title: Army Research Office (ARO) Overview and Physics Division
Objectives
Abstract: The headquarters of the Army Research Office (ARO) is
located in Raleigh-Durham, North Carolina, USA. The ARO funds
excellent basic research in the sciences. In fact, ARO has funded
numerous Nobel laureates over the years. The majority of ARO
funding goes to U.S. researchers. However, two years ago, the ARO
has started an International Program. I am the Program Manager for
the International Program in Physics. My geographical area is the
whole world, excluding the continental U.S. (which is covered by
other ARO program managers in the U.S.). My goal is to find
exceptional basic physics research that is done outside of the
continental U.S. My Program is called "Quantum Scale Materials",
and it deals with a broad area of quantum physics, including
topological physics, quantum sensors, and a variety of other
quantum-related physics. My office is in the Roppongi district of
Tokyo, Japan. In this talk, I will give an overview of the ARO
organization, the International Program, and the Physics Division.
I will describe the goals of the ARO International Program in
Physics in Asia-Pacific. Finally, I will describe the process of
submitting a research proposal to ARO.
Chair: Prof. Adam Miranowicz
Seminar language: English
/487/
Date: Wednesday 2019.10.02 at 13:00
Speaker: Prof. John Williamson
Affiliation: Professor emeritus at the College of Science and Engineering, University of Glasgow, UK
Title: An extension of the Maxwell equations, describing both light and
material particles
Abstract: A space-time algebra incorporating a sharpening of the principle
of relativity allows all four Maxwell equations to be written in a
particularly simple and elegant way as dF=0, where dF is the
four-vector differential of the electromagnetic field. Defining
the new two component rest mass as M second order equations such
as d(d(F+M))=0 lead to four new equations coupling intrinsic spin
and 4-current (Williamson, IOP conf. 2019). The result leads to
an explicit, dynamical interaction between mass and field, through
current and intrinsic spin, confining each with respect to the
other. The resulting new quantised solutions over and above the
photon ones correspond to fermionic vortices in momentum space.
These are necessarily charged and have an intrinsic 720 degree
symmetry. They are physical mass-field spinors. There are four and
only four such solutions, distinguished from each other by the
charge and spin signs. The charge may be calculated, and gives a
value close to the elementary charge. The four new solutions are
identified with the spin up and down electron and positron. The
theory throws light in the way electrons behave from being
point-like in ultra high energy collisions, to becoming
quantum-mechanically extended in the solid state with size scales
of tens of nanometers (Williamson et. al. Phys Rev, 1990). The new
theory therefore allows hitherto unprecedented insights into the
design, development and properties of new quantum materials and
devices.
Biography: John Williamson worked at CERN for seven years, in the advanced
theoretical and experimental physics group in Philips for five
years, and in the College of Science and Engineering in Glasgow
University for 27 years. He is currently leading an international
research group, the quicycle (quantum bicycle) society. He has
published widely in the fields of elementary particle physics,
quantum transport in nanoelectronics, and in quantum field theory.
He has (co-)authored over a hundred papers. He has an h-index of
45 and over twelve thousand citations.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/487/
Date: Wednesday 2019.09.11 at 13:00
Speaker: Dr. Kirill Shulga
Affiliation: RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
Title: Time crystals based on superconducting quantum circuits
Abstract: Investigation of many-body spin systems in cQED (Cavity quantum electrodynamics) enable applications of quantum simulators with superconducting quantum circuits. In our work, we perform experimental studies of time-resolved spin dynamic of superconducting qubit arrays embedded into a superconducting resonator. We use the superconducting qubit arrays for the demonstration of an occurrence of quasi-periodic many-body Rabi oscillations and complex spin dynamics in the dispersion and the resonance regimes with tunable interaction strengths between the qubits and the cavity. In particular, we experimentally explore a possibility to realize a time crystalline order in an array of superconducting qubits embedded in a superconducting resonator by applying periodic sequence of microwave pulses with excitation of nonequilibrium states in the system. Focusing on time crystals consisting of a small number of artificial atoms, we attempted to show the microscopic processes responsible for the appearance of the time crystalline order parameter.
Chair: Prof. Adam Miranowicz
Seminar language: English
/485/
Data: środa, 10.07.2019, godz. 13:00
Prelegent: Prof. Maciej Błaszak
Afiliacja: Zakład Fizyki Matematycznej, Wydział Fizyki, UAM
Tytuł: Quantum versus Classical Mechanics and Integrability
Problems – towards a unification of approaches and tools
Prowadzący: Prof. Maciej Krawczyk
Seminar language: English
/484/
Data: środa, 2.07.2019, godz. 13:00
Prelegent: Dr Ewelina Milińska
Afiliacja: Instytut Fizyki Polskiej Akademii Nauk w Warszawie
Tytuł: Przestrzenne zmiany anizotropii magnetycznej w
wielowarstwowych układach magnetycznych
Streszczenie: Umiejętność kontrolowania lokalnych zmian właściwości
magnetycznych w heterostrukturach magnetycznych cieszy się
zainteresowaniem badaczy zarówno ze względu na badania podstawowe
materiałów, jak również na potencjalnie szerokie zastosowanie
układów o modulowanych właściwościach magnetycznych. Lokalną
zmianę anizotropii magnetycznej można uzyskać poprzez zastosowanie
strukturyzowanego bufora, który wymusza przestrzenną modulację
magnetycznych właściwości w osadzonej na jego powierzchni ciągłej
warstwie Co [1]. Innym przykładem manipulacji parametrami
magnetycznymi heterostruktury jest jej lokalne naświetlanie wiązką
jonów bądź lasera. Zmiana parametrów naświetlania, tj. zmiana typu
jonów czy natężenia wiązki, jak również zmiana struktury próbki
(jak np. grubość warstwy wierzchniej), wpływa na kierunek
namagnesowania warstwy Co o określonej grubości [2,3]. Co więcej,
naświetlanie układu Pt/Co/Pt jonami Ga+ w formie równoległych
pasków można wykorzystać do stworzenia jednowymiarowej,
periodycznej magnetycznie struktury, o zmiennym kierunku
namagnesowania. Nasze wyniki pokazują także, że w układzie
Co/Mo/Co naświetlanie jonami Ga+ zmienia typ oddziaływania między
magnetycznymi warstwami. Przełączenie jest zależne od
referencyjnego (nienaświetlonego) stanu i dobranych parametrów
padającej wiązki jonów. W szczególności, możliwym jest uzyskanie
zmiany sprzężenia międzywarstwowego z anty-równoległego na
równoległe. Periodyczna zmiana takich sprzężeń może być
rozpatrywana jako dwuwarstwowy (dwukanałowy) kryształ magnoniczny.
Innym sposobem wprowadzenia periodycznych zmian właściwości
magnetycznych jest wytworzenie jednowymiarowych kryształów przez
manipulację ich strukturą domenową. Oscylujący kierunek
namagnesowania tworzy się np. w układach wielowarstwowych typu
W/Co/Pt. Początkowo labiryntowa struktura domenowa może być
przeformowana do równoległych paskowych struktur przez
zastosowanie odpowiedniej procedury rozmagnesowania. Badany układ
wielowarstwowy powinien wykazywać silne oddziaływanie iDMI, które
jest przedmiotem dalszych badań. W periodycznych układach
wytworzonych omawianymi sposobami propagacja fal spinowych powinna
być kontrolowalna i charakteryzować się odmienną strukturą
pasmową względem jednorodnego magnetycznie ośrodka.
Praca jest realizowana w ramach programu POWROTY 2017 Fundacji na rzecz Nauki Polskiej współfinansowanego przez Unię Europejską z Europejskiego Funduszu Rozwoju Regionalnego.
[1] A. Wawro, E. Sieczkowska, A. Petroutchik, L.T. Baczewski, Z. Kurant, and A. Maziewski, Local variation of ultrathin Co film magnetization orientation induced by a structured buffer: Magnetic dots, Phys. Rev. B 83, 092405 (2011).
[2] A. Maziewski, P. Mazalski, Z. Kurant, M. O. Liedke, J. McCord, J. Fassbender, J. Ferré, A. Mougin, A. Wawro, L. T. Baczewski, A. Rogalev, F. Wilhelm, and T. Gemming, Tailoring of magnetism in Pt/Co/Pt ultrathin films by ion irradiation, Phys. Rev. B 85, 054427 (2012).
[3] M. M. Jakubowski, M. O. Liedke, M. Butterling, E. Dynowska, I.
Sveklo, E. Milińska, Z. Kurant, R. Böttger, J. von Borany, A.
Maziewski, A. Wagner and A. Wawro “On defects role in enhanced
perpendicular magnetic anisotropy in Pt/Co/Pt, induced by ion
irradiation,” J. Phys. Condens. Matter, (2019).
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/483/
Data: wtorek, 2.07.2019, godz. 13:00
Prelegent: Dr Jan Kisielewski
Afiliacja: Wydział Fizyki, Uniwersytet w Białymstoku
Tytuł: Rozmagnesowanie i tworzenie domen magnetycznych
pojedynczymi impulsami lasera femtosekundowego
Streszczenie: Ultracienkie układy Pt/Co/Pt naświetlano pojedynczymi
impulsami lasera femtosekundowego. W miejscu naświetlania próbka
uległa rozmagnesowaniu. Wykorzystując mikroskopię sił
magnetycznych (MFM) zaobserwowano powstanie domen magnetycznych o
sub-mikronowych rozmiarach. Proces rozmagnesowania poprzez
naświetlania impulsami światła był całkowicie odwracalny.
Scharakteryzowano warunki, w których możliwe jest wystąpienie
takiego rozmagnesowania – gęstość energii impulsu musi być większa
od pewnej progowej wartości, która zależy od anizotropii
magnetycznej. Proces tworzenia domen magnetycznych i jego
termiczna natura znajdują potwierdzenie w wynikach symulacji
mikromagnetycznych, wykorzystujących równanie
Landaua-Lifshitza-Blocha. Przedstawione zostaną również wyniki
modelowania mikromagnetycznego rozkładów magnetyzacji z
wykorzystaniem oddziaływania Działoszyńskiego-Moriyi.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/482/
Date: Friday 2019.06.28 at 12:00
Speaker: Prof. Jamal Berakdar
Affiliation: Institut für Physik, Martin-Luther-Universität
Halle-Wittenberg, Halle (Saale), Germany
Title: Computing with twisted chiral magnons
Abstract: Low-energy eigenmode excitations of magnetically ordered
systems are spin waves that can be quantified by quasiparticles
termed magnons. Magnons can be thermally and non-thermally
excited, confined, spectrally shaped, and guided by material
design [1]. Magnonic currents are routinely generated at low
energy cost and do not suffer from Ohmic losses, which make them
an attractive medium for communication, and processing of
information. Here we present topologically non-trivial (spatially
structured) magnons that carry a definite and electrically tunable
projection of the orbital angular momentum constituting onto the
propagation direction. Such beams we term helical or ”twisted
magnon beams” [2]. Starting from fundamental equations for spin
dynamics we discuss how twsited beams emerge in magnonic
waveguides and how to topologically quantify and steer them. A key
finding is that the topological charge associated with the twist
of a particular beam is tunable externally and protected against
damping in a ferromagnetic system. Coupling to an external
electric field via the Aharanov-Casher effect allows for
electrical tuning of the topological charge. This renders possible
twist-based robust, low-energy consuming multiplex magnonic
computing, analogously to using photonic orbital angular momentum
in optical communications [3], but here at shorter wavelength and
lower energy consumption, and ready integration in magnonic
circuits utilizing the versatile toolbox for material and spin
waves engineering. Both ferro- and antiferromagnetic magnons will
be discussed.
[1] Chumak, A. V. et al., Nature Physics 11,
453 (2015).
[2] Jia, C.L. et al., Nat. Comm. 10, 1 (2019).
[3] Willner, A. E. et al., Adv. Opt. Photon. 7, 66 (2015).
Chair: Dr Anna Dyrdał
Seminar language: English
/481/
Date: Monday 2019.06.24 at 13:00
Speaker: Prof. Kong Liu
Affiliation: Key Lab of Semiconductor Materials Science, Institute
of Semiconductors, Chinese Academy of Science (CAS), Beijing,
China
Title: Carrier dynamics in organic and perovskite solar cells
Abstract: To enable organic solar cells with a competent charge
transport efficiency, reducing the thickness of active layer
without sacrificing light absorption efficiency turns out to be of
high feasibility. Herein, organic solar cells on wrinkled metal
surface are designed. This structure could improve light capture,
mitigate defect recombination and benefits charge transport and
collection. Besides, we found that transport layer modification
and doping could benefit charge extraction of the organic solar
cells. A flexible organic solar cell was also fabricated with our
optimized materials. For perovskite solar cells, we found that
20% Cs and 10% Cl were beneficial for structural, morphological,
opto-electronic and photovoltaic properties. Besides, perovskite
with additives of DRCN5T, MACl and MAH2PO2 presents improved
morphological and charge dynamic properties. A 25.4%-efficient
monolithic perovskite/Si tandem solar cell was also obtained.
Chair: Prof. Marcin Ziółek
Seminar language: English
/480/
Date: Wednesday 2019.06.12 at 13:00
Speaker: Dr. Thomas Vasileiadis
Affiliation: Fritz Haber Institute of the Max Planck Society,
Berlin, Germany
Title: Ultrafast Energy Flow and Structural Changes in Nanoscale
Heterostructures
Abstract: A central goal of nanotechnology is the precise
synthesis of nanostructures with optimized functionalities. The
functionalities of nanostructures are controlled by external
stimuli such as pulses of light, current or heat. This brings up
the question: what is the connection between nonequilibrium
conditions and structural stability at the nanoscale? To answer
this question, we employ femtosecond electron diffraction [1] to
study ultrafast energy flow and structural changes in
heterostructures of size-selected Au923 nanoclusters, or Au
nanoislands, on semiconducting thin-films. Au923 nanoclusters are
found to exhibit ultrafast surface premelting at atypically low
lattice temperatures and pronounced electron-lattice
nonequilibrium conditions [2]. Furthermore, the phonons of a
crystalline substrate (graphene) scatter on the adsorbed Au923
nanoclusters and induce nanocluster-rotations at picosecond
timescales [3]. Finally, surface decoration with plasmonic,
quasi-2D Au nanoislands sensitizes the semiconducting WSe2 to
sub-band-gap photons and accelerates its electron-phonon
equilibration times. All the above phenomena are considered
important for the stability of nano-catalysts and the efficiency
of plasmonic solar cells. This research stemmed from an
international collaboration between the research group Structural
|
Electronic Surface Dynamics headed by Ralph Ernstorfer (FHI
Berlin) and the groups of Richard Palmer (Swansea University in
UK), Laurenz Rettig (FHI Berlin), Vlasios Mavrantzas (ETH Zurich
and University of Patras) and Stephanie Reich (Free University of
Berlin).
[1] Lutz Waldecker et al., Journal of Applied
Physics 117, 044903 (2015).
[2] Thomas Vasileiadis et al., ACS
Nano 12 (8), 7710-7720 (2018).
[3] Thomas Vasileiadis et al.,
Nanoscale Horizons (2019).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/479/
Date: Thursday 2019.06.06 at 13:00
Speaker: Dr. Hong-Bin Chen
Title: Process nonclassicality: Characterization, canonical
Hamiltonian ensemble representation, and quantification
Authors: Hong-Bin Chen (1), Ping-Yuan Lo (2), Clemens Gneiting
(3), Joonwoo Bae (4), Yueh-Nan Chen (1), and Franco Nori (3,5)
Addresses:
(1) Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
(2) Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
(3) Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
(4) School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
(5) Physics Department, University of Michigan, Ann Arbor,
Michigan 48109-1040, USA
Abstract: The characterization, explanation, and quantification of
quantumness, in particular the discrimination from classicality in
terms of classical strategies, lie at the heart of quantum
physics. Recently, it is shown that dynamical processes can
exhibit classical or nonclassical traits, depending on the nature
of the system-environment correlations and the related
(im)possibility to simulate these dynamics with Hamiltonian
ensembles - the classical strategy. Here we propose to extend this
classification towards quantifying the nonclassicality. In the
spirit of Wigner function, we generalize Hamiltonian ensembles to
encompass quasi-probability distributions comprising negative
values. Based on Lie algebra representations, Fourier transforms
on groups, and root space decompositions, we demonstrate that
quasi-probability distributions are faithful representations of
pure dephasing dynamics; moreover, we show how to retrieve these
quasi-probability distributions. This allows us to quantify
process-nonclassicality time-independently, in terms of the
deviations of the corresponding quasi-probability distributions
from legitimate (non-negative) probability distributions.
Chair: Prof. Adam Miranowicz
Seminar language: English
/478/
Date: Friday 2019.05.31 at 11:00
Speaker: Prof. Maciej Kozak
Affiliation: Department of Macromolecular Physics, Faculty of
Physics, AMU
Title: NCPS Solaris and current status of SOLCRYS beamline
Abstract: NCPS Solaris is a modern, low emittance synchrotron
radiation source based on the storage ring (1.5 GeV) built in
Double-Bend Achromat technology. The facility since 2017 is open
for users, and currently offering two beamlines - ultra
angle-resolved photoemission spectroscopy (UARPES) and PEEM/XAS.
Next two beamlines (XMCD and XPS) are in construction or
installation phase. The plans for the development of the NCPS
include the construction of further beamlines. Currently, in
cooperation with JINR Dubna, the design works for a modern
beamline – SOLCRYS, dedicated for diffraction studies and
small-angle X-ray scattering have been initiated. SOLCRYS beamline
will utilize a superconducting multipole 4-Tesla wiggler as the
efficient X-ray source (up to 25 keV). The synchrotron radiation
beam from the source will be divided into two independent
branches. During the seminar the details of the project and recent
results of numerical simulations of X-ray optics for both
branches, carried out using the ray-tracing method will be
presented.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/477/
Date: Tuesday 2019.05.21 at 13:00
Speaker: Prof. Taksu Cheon
Affiliation: Laboratory of Physics, Kochi University of
Technology, Tosa Yamada, Kochi, Japan
Title: Introduction to opinion dynamics
Abstract: Majority rule is a ubiquitous principle of collective
decision making in social animals from bee to human. Despite its
apparent simplicity, there are many paradoxical phenomena in
democratic majority rule, such as the persistence of powerful
dominating minority and majority-assisting function of contrarian
opponents. In this talk, I introduce “opinion dynamics”, which has
been developed in search of a mathematical model describing the
realistic features of majority rule. We detail its structure,
mathematical properties and predictions.
Ref: arXiv:1901.09622 . Slides for the talk are here.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/476/
Date: Monday 2019.05.20 at 11:00
Speaker: Prof. Taksu Cheon
Affiliation: Laboratory of Physics, Kochi University of
Technology, Tosa Yamada, Kochi, Japan
Title: Some aspects of quantum graph theory
Abstract: The quantum graph is a concept describing a system of
quantum particles on graphs made up of lines and vertices. It is
a mathematical and solvable model of nano wire-based and quantum
dot-based single-electron devices. We point out the existence of
several intriguing nontrivial features of quantum graphs such as
threshold resonance and controlled spectral filtering of quantum
flux, and discuss their application in modeling and designing of
quantum devices.
Ref: arXiv:1203.6555 . Slides for the talk are here.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/475/
Date: Monday 2019.05.20 at 10:00
Speaker: Prof. Shinichiro Sakikawa
Affiliation: International Relations Center, Kochi University of
Technology, Tosa Yamada, Kochi, Japan
Title: Research cooperation with Kochi University of Technology
Chair: Prof. Maciej Krawczyk
Seminar language: English
/474/
Date: Wednesday 2019.05.15 at 13:00
Speaker: Dr. Nicholas Sedlmayr
Affiliation: Department of Physics and Medical Engineering,
Rzeszów University of Technology
Title: The Superconductivity of Topologically Protected Surface
States
Abstract: The superconducting proximity effect induced in
materials in close contact with a superconductor is well
established. We reveal that similarly the topologically protected
surface states recently found on the surfaces of special crystals
can leak into appropriate adjoining materials. We bring these two
effects into proximity and study how superconductivity and
topologically protected surface states interact with each other, a
situation of interest in the search for Majorana bound states. We
look at the scanning tunneling microscopy of a large topological
insulator with superconducting islands deposited on the surface,
and analyze theoretical models which capture the hybridization
between the topological surface states and the superconducting
states. The density of states of both the topological insulator
and the superconductor turn out to exhibit interesting proximity
effects and open up new possibilities for observing Majoranas.
Chair: Prof. Ireneusz Weymann
Seminar language: English
/473/
Date: Wednesday 2019.04.17 at 13:00
Speaker: Dr. Konrad J. Kapcia
Affiliation: Department of Computational Materials Science,
Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
Title: Exact phase diagram of the infinite-dimensional extended
Falicov-Kimball model
Abstract: The Falicov-Kimball model [1] is a simplified version
of the Hubbard model [2], where only electrons with, e.g., spin
down are itinerant and the other are localized. During the
seminar, we will discuss results for the extended Falicov-Kimball
model at half-filling on the Bethe lattice in the limit of large
dimensions derived within the DMFT formalism [3-7], which is a
rigorous approach in this limit. The on-site and the intersite
density-density interactions between particles occupying
neighboring sites are included in the hamiltonian [5-7]. We
determined the exact phase diagrams of the model both in the
ground state [6] and at finite temperatures [7]. Using analytical
formulas we showed that in the ground state the system is an
insulator for any non-zero values of the interaction couplings and
we detected the discontinuous transition between two different
charge-ordered phases [6]. The finite temperature diagrams are a
generalization of the diagram previously obtained in Ref. [4] for
the standard Falicov-Kimball model, but they are much richer than
it. In particular, it turns out that these diagrams contain more
types of ordered phases, both conductive and insulating, and phase
transitions between them are either continuous or discontinuous
[7]. What is more, it turns out that in a certain range of
interaction parameters the order-disorder phase transition may be
discontinuous.
[1] L.M. Falicov, J.C. Kimball, Phys. Rev. Lett. 22, 997 (1969); R. Ramirez, L.M. Falicov, J.C. Kimball, Phys. Rev. B 2, 3383 (1970).
[2] J. Hubbard, Proc. R. Soc. London, Ser. A 276, 238 (1963).
[3] J.K. Freericks, V. Zlatic, Rev. Mod. Phys. 75, 1333 (2003); A. Georges, G. Kotliar, W. Krauth, M.J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996).
[4] R. Lemański, K. Ziegler, Phys. Rev. B 89, 075104 (2014); S.R. Hassan, H.R. Krishnamurthy, Phys. Rev. B 76, 205109 (2007).
[5] P.G.J. van Dongen, D. Vollhardt, Phys. Rev. Lett. 65, 1663 (1990); P.G.J. van Dongen, Phys. Rev. B 45, 2267 (1992).
[6] R. Lemański, K.J. Kapcia, S. Robaszkiewicz, Phys. Rev B 96, 205102 (2017).
[7] K.J. Kapcia, R. Lemański, S. Robaszkiewicz, preprint, arXiv:
1903.08092 (2019).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/472/
Data: środa 2019.04.10, godz. 13:00
Prelegent: Dr Aneta Woźniak-Braszak
Afiliacja: Zakład Fizyki Wysokich Ciśnień, WF UAM
Tytuł: Technika NMR poza rezonansem jako metoda do badania
wolnych ruchów molekularnych w układach homo- i heterojądrowych
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/471/
Date: Wednesday 2019.04.3 at 13:00
Speaker: Dr hab. Michał Michałowski
Affiliation: Astronomical Observatory, Faculty of Physics, Adam
Mickiewicz University in Poznań
Title: The discovery of a hot cocoon around an exploding
supernova
Abstract: I will present the results of observations (including
those with PST2/RBT) of a gamma-ray burst (GRB) 171205A and the
associated supernova (SN) 2017iuk, which led to the discovery of a
hot gas cocoon. This was possible because observations started
very early and the jet emission was weak. This gives support to
the theoretical models of GRB/SN explosions, which predicted the
existence of such a cocoon. This discovery opens the possibility
to study internal processes during explosions of very massive
stars, and hence will shed light on the understanding of the
production of heavy elements.
Chair: Prof. UAM Agnieszka Kryszczyńska
Seminar language: English
/470/
Date: Thursday 2019.03.28 at 14:00
Speaker: Prof. Vladislav E. Demidov
Affiliation: Institute for Applied Physics and Center for
Nanotechnology, University of Muenster, Germany
Title: Excitation and amplification of coherent spin waves by spin
currents
Abstract: In this talk, I review our recent experiments on
utilization of pure spin currents created by the spin-Hall effect
and the nonlocal spin injection for excitation and manipulation of
coherent propagating spin waves in magnonic nano-structures based
on metallic and insulating magnetic films. I show that spin
currents enable novel functionalities of magnonic devices not
achievable by using traditional approaches. In particular, spin
currents allow highly efficient excitation of continuous spin
waves and short spin-wave packets with the duration down to a few
nanoseconds exhibiting nonlinear self-stabilization during
propagation. These demonstrations open a route for implementation
of high-speed magnonic devices characterized by high information
flow capacity.
[1] V. E. Demidov et al., Nat. Commun. 7, 10446 (2016).
[2] V. E. Demidov et al., Phys. Rep. 673, 1 (2017).
[3] B. Divinskiy et al., Adv. Mater. 30, 1802837 (2018).
[4] M. Evelt et al., Phys. Rev. Appl. 10, 041002 (2018).
Chair: Prof. Sławomir Mielcarek
Seminar language: English
/469/
Date: Wednesday 2019.03.27 at 13:00
Speaker: Dr. Anna Dyrdał
Affiliation: Mesoscopic Physics Division, Faculty of Physics, Adam
Mickiewicz University in Poznań and Institut für Physik,
Martin-Luther Universität Halle-Wittenberg, Germany
Title: Non-equilibrium spin-orbit driven phenomena in
two-dimensional systems (habilitation seminar)
Abstract: Spin-orbit interaction leads to the mixing of orbital
and spin degrees of freedom and is responsible for a variety of
spin and transport phenomena such as anisotropic
magnetoresistance, anomalous and spin Hall effects,
non-equilibrium spin polarization and spin-orbit torques. Recently
under special attention are two non-equilibrium effects
responsible for the efficient spin-to-charge conversion: the spin
Hall effect and current-induced spin polarization. Both of them
opens a unique possibility of pure electrical control of the spin
degree of freedom and have been already used as an effective tool
for the generation and detection of spin currents and the
so-called spin-orbit torques. The physics that stands behind
such effects is very rich and depends on the nature of spin-orbit
coupling in the host material. Importantly, the spin-orbital
effects are strongly enhanced in low-dimensional structures where
the lack of inversion symmetry leads to large Rashba effect. Thus,
the natural platforms for spin-orbitronics are the interfaces of
semiconductor heterostructures, surfaces of topological
insulators, two-dimensional van der Waals heterostructures, and
perovskite-oxides heterointerfaces.
During this seminar, I will discuss and summarize results that I
obtained within the research on spin-to-charge conversion in
semiconductor heterostructures and graphene-like hybrid
structures. I will focus on the behaviour of spin Nernst and
spin Hall effect beyond the zero-temperature limit in a
two-dimensional electron gas that might appear in semiconductor
heterostructures. Next, I will summarize the properties of
anomalous, spin and valley Hall effects in graphene-based hybrid
structures. Then, I will present results obtained for electrically
and thermally induced non-equilibrium spin polarization in such
systems. During the presentation, I will mention about such
aspects as the interplay between effective exchange field and
spin-orbit interaction, and the role of a Berry phase in the
system responses. In the last part of the seminar, I will also
briefly discuss the fingerprints of spin-orbit driven phenomena in
the magnetoresistance effects.
Chair: Prof. Michał Banaszak
Seminar language: English
/468/
Data: środa 2019.03.20, godz. 13:00
Prelegent: Dr Andrzej Ptok
Afiliacja: Instytut Fizyki Jądrowej PAN w Krakowie
Tytuł: Stany związane Majorany – realizacja oraz manipulacja
Streszczenie: W układach o niskiej wymiarowości mogą być indukowane
stany związane o zerowej energii, zwane stanami Majorany [1].
Obecne eksperymenty, m.in. w układzie ferromagnetycznych atomów na
powierzchni nadprzewodnika [2] lub nanostruktur hybrydowych
półprzewodnik—nadprzewodnik [3], potwierdzają istnienie tych
stanów. Ze względu na swoje topologiczne własności, wierzy się, że
stany Majorany mogą być wykorzystane do budowy kwantowych
komputerów. Podczas wystąpienia przedstawię wyniki eksperymentalne
pokazujące realizację stanów związanych Majorany. Omówię
podstawowe własności quasi-cząstek Majorany na przykładzie
układzie kropki kwantowej połączonej z nanodrutem [4]. Ze względów
praktycznych, istotne jest aby w sposób kontrolowany wytwarzać
stany Majorany oraz w prosty sposób nimi manipulować –
zaprezentuje w jaki sposób stany te mogą być ”wytwarzane” w
układzie półprzewodnikowego nieopierścieniana z kropką kwantową
[5] oraz układzie ultra-zimnych gazów fermionowe w pułapce
optycznej [6].
[1] A. Y. Kitaev, Phys.—Usp. 44, 131(2001).
[2] S. Jeon, Y, Xie, J. Li, Z. Wang, B. A. Bernevig and A. Yazdani, Science 358, 772 (2017).
[3] V. Mourik, K. Zuo, S. M. Frolov, S. R. Plissard, E.P.A.M. Bakkers L.P. and Kouwenhoven, Science 336, 1003 (2012).
[4] A. Ptok, A. Kobiałka and T. Domański, Phys. Rev. B 96, 195430 (2017).
[5] A. Ptok, A. Cichy and T. Domański, J. Phys.: Condens. Matter 30, 355602 (2018).
[6] A. Kobiałka and A. Ptok, J. Phys.: Condens. Matter 31, 185302
(2019).
Prowadząca: Dr Agnieszka Cichy
Seminar language: Polish
/467/
Date: Wednesday 2019.03.13 at 13:00
Speaker: Dr Bartłomiej Graczykowski
Affiliation: Zakład Biofizyki Molekularnej, WF UAM
Title: Phonon transport in quasi two-dimensional nanostructures
(habilitation seminar)
Abstract: The aim of the presented research was to investigate the
GHz-THz phonon propagation in quasi two-dimensional materials of
importance for future emerging applications by means of developed
and dedicated experimental techniques. I have investigated several
strategies to tailor the phonon dispersion and the phonon MFP. In
particular, these were: spatial 1D confinement, periodic
patterning, implementation of local resonances, static stress and
dense grain boundaries. The key scientific questions which I have
considered are summarized by the following objectives: (a) To
determine the influence of spatial confinement and static stress
on the hypersonic phonon propagation and intrinsic elastic
properties for the crystalline ultra-thin membranes. (b) To
investigate the breakdown of bulk elastic properties under 1D
spatial confinement and with dense grain boundaries. (c) To
investigate the role of sub-micrometer periodic repetition of
motifs as holes and pillars in/on Si membranes in hypersonic
phonon dispersion. (d) To investigate the reduction of the thermal
conductivity and its temperature dependence in holey PnCs at high
temperatures (300-1000 K). (e) To quantify air-mediated heat
dissipation (losses) in holey PnCs. (f) To determine the role of
the structure imperfection as the surface roughness, fabrication
precision and intentional disorder on the coherent (wave-like)
effects in membrane based PnCs.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/466/
Date: Wednesday 2019.03.6 at 11:00
Speaker: Prof. Deji Akinwande
Affiliation: Microelectronics Research Center, The University of
Texas at Austin, Austin, USA
Title: Adventures with 2D Materials: From Flexible Devices to
Atomic Memories and Electronic Tattoo Sensors
Chair: Dr. hab. Maciej Wiesner
Seminar language: English
/465/
Data: środa 2019.02.27, godz. 13:00
Prelegent: Dr hab. Wojciech Florek
Afiliacja: Zakład Fizyki Komputerowej, WF UAM
Tytuł: Sfrustrowane geometrycznie skończone układy spinowe:
degeneracja, chiralność, dwudzielność
(Geometrically frustrated
finite spin systems: degeneration, chirality, bipartiteness)
-
seminarium profesorskie
Streszczenie: W badaniach sfrustrowanych układów izingowskich
przyjmuje się, że jednym z istotnych efektów jest wysoka
degeneracja stanu podstawowego. Podobnie w przypadku (skończonych)
układów kwantowych O. Kahn podkreślał znaczenie degeneracji
wprowadzając termin „degenerate frustration”. Synteza i badanie
sfrustrowanych geometrycznie molekuł magnetycznych wskazało, że
możliwe jest występowanie układów, w których frustracji
geometrycznej nie towarzyszy degeneracja stanu podstawowego. Co
więcej, nie jest to li tylko efekt skończoności układu
(dyskretności widma hamiltonianu), gdyż w wielu przypadkach to
zachowanie jest uniwersalne: nie zależy od rozmiaru układu (liczby
spinów) i wartości momentów magnetycznych (liczb spinowych). W
omawianych badaniach analizowane są trzy klasy molekuł tego typu.
W każdym przypadku jako podstawowy rozpatrywany jest izotropowy
model Heisenberga, a jednocześnie analizowane są jego analogi:
model klasyczny i model Isinga. Każdy z tych modeli ma swoje
specyficzne właściwości, jednak wspomniany powyżej efekt występuje
we wszystkich trzech przypadkach.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/464/
Date: Thursday 2019.02.21 at 12:00
Speaker: Dr. Susmita Saha
Affiliation: Department of Materials, ETH Zurich, Zurich,
Switzerland and Paul Scherrer Institut, Villigen, Switzerland
Title: Skyrmion Confinement and Damping Modulation in Magnetic
Thin Films
Abstract: Magnetic skyrmions [1, 2] are topologically protected
nanometer sized chiral spin textures with an out of plane magnetic
domain at the center. Due to their various unique features such as
stability given by their topology, they are considered as
potential candidates for information carriers in next generation
data storage devices, like racetrack memory. For such
applications, it is crucial to be able to manipulate their
current-induced motion in various directions. In this work, we
present stable nanoscopic skyrmions confined by an array of
antidots. Utilizing the induced periodic potential of the antidot
lattice, we propose a method for unprecedented control of the
skyrmion dynamics. But for that purpose it is also important to
understand and control the damping in ferromagnetic thin films.
One of the possible ways to manipulate magnetic damping is
injection of spin current generated due to spin Hall effect [3]
which is an emerging phenomenon where the properties of electrical
charge current can be transferred to the electron’s intrinsic
angular momentum (spin current), and vice versa. To measure the
modulation of damping, we use a time-resolved magneto-optical Kerr
effect microscope (TR-MOKE), which has the best spatial and
temporal resolution to measure the damping of the ferromagnetic
film. The observations will have a strong impact on the
development of spintronics devices, such as spin transfer torque
nano-oscillators or domain wall racetrack
memories.
Acknowledgement: We acknowledge ETH Zurich Post Doctoral
fellowship and Marie Curie actions for People COFUND program and
Dr. S. Wintz, Dr. N. S. Bingham, Dr. A. K. Suszka and Mr. T. P.
Dao for technical support and valuable discussions.
References:
[1] D. A. Gilbert et. al., Nat. Commun. 6, 8462 (2015).
[2] O. Boulle et. al., Nat. Nanotech. 11, 449 (2016).
[3] L. Liu et. Al., Science, 336, 555 (2012).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/463/
Date: Wednesday 2019.02.20 at 13:00
Speaker: Prof. Nelson Darkwah Oppong
Affiliation: Ludwig-Maximilians-Universität München and
Max-Planck-Institut für Quantenoptik
Title: Exploring impurity physics with two-orbital quantum gases
Abstract: Interactions of impurities with their environment govern
many interesting quantum many-body phenomena in condensed matter
systems, for example the Kondo effect. In particular, ultracold
atoms provide an excellent platform for studying impurity physics
due the precise control and independent tunability of experimental
parameters. While impurities in single-orbital ultracold quantum
gases have been studied, multi-orbital systems have not yet been
explored. Fortunately, alkaline-earth(-like) atoms (AEAs), such as
ytterbium and strontium, feature a metastable electronic state,
which is long-lived and can be utilized as an orbital degree of
freedom. This so-called clock state makes AEAs promising
candidates for the implementation of two-orbital physics. In our
experiment, we use fermionic ytterbium-173 to realize and probe
impurities in two-orbital many-body systems.
First, I report on our recent efforts to implement Kondo physics
in state-dependent optical lattices. We demonstrate orbital
dependent mobility in these lattices and show that interorbital
spin exchange, comparable to the coupling in the Kondo model, is
present in this system.
Second, I discuss our most recent results on the observation of
multi-orbital polarons in a two-dimensional Fermi gas. We
precisely characterize these long-lived quasiparticles which are
formed by mobile impurities interacting with a Fermi sea.
Chair: Dr. Agnieszka Cichy
Seminar language: English
/462/
Date: Wednesday 2019.02.13 at 13:00
Speaker: Dr. Kosma Szutkowski
Affiliation: Centrum NanoBioMedyczne UAM, Poznań
Title: Physical insights in selected macromolecular and
self-assembling systems from translational dynamics studied by
Nuclear Magnetic Resonance techniques (habilitation talk)
Abstract: Translational dynamics in soft-matter systems is related
to spatial translations of atoms or molecules. Those translations
can be accurately measured using Nuclear Magnetic Resonance
spectroscopy given that the motion of nuclear spins is associated
with a change of the magnetic field followed by a shift in the
Larmor precession frequencies. We utilise the fact that the
variations of the magnetic field can be either a feature of the
system (local magnetic field inhomogeneities) or can be generated
on purpose, using artificially created magnetic field gradient
(spin labelling). In this talk, several unique applications of
Nuclear Magnetic Resonance spectroscopy to translational dynamics
problems in macromolecular and self-assembling systems will be
presented. In particular, the following topics will be discussed:
(a) self-diffusion studied for star-polymers in melt (1H PGSE
NMR), (b) real-time self-diffusion experiments based on the
magnetization grating (1H OUFIS single-shot diffusion NMR), (b)
two-site proton hopping via hydrogen bonds upon aggregation of
surfactants in aqueous solutions (1H CPMG T2 dispersion
NMR), (c) an impact of interactions between BSA and Gemini
surfactants on self-diffusion coefficients (1H PGSE NMR), (d)
an impact of aggregation of peptides on self-diffusion
coefficients (1H PGSE NMR), (e) concentration-dependent
aggregation of Gemini surfactants observed via self-diffusion
coefficients (1H Bayesian-DOSY NMR), (f) peptides snorkeling in
micellar environments and its impact on the internal translational
dynamics of surfactants in micelles (31P CPMG T2
dispersion NMR, 1H/2H/31P PGSE NMR).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/461/
Data: poniedziałek 2019.02.11, godz. 12.00
Prelegent: Dr hab. Gotard Burdziński
Afiliacja: Zakład Elektroniki Kwantowej, WF, UAM
Tytuł: Mechanizm dezaktywacji fotowzbudzonych betalain i
3H-naftopiranów (Seminarium profesorskie)
Streszczenie: Betalainy to betaksantyny i betacyjaniny stanowiące
ważną grupę barwników naturalnych, występujących w roślinach z
rzędu Caryophyllales, a także w niektórych grzybach wyższych.
Naszym celem badawczym był opis właściwości fotofizycznych tych
barwników na podstawie wyników czasowo-rozdzielczej spektroskopii
absorpcji przejściowej w zakresie UV-vis-NIR. Wyznaczone czasy
życia betalain w stanie S1 w roztworach wodnych i alkoholowych są
krótkie (w przybliżeniu 10 ps u betacyjanin i 50 ps u betaksantyn
w wodzie). Układ molekularny w stanie wzbudzonym S1 osiąga punkt
przecięcia stożkowego na skutek zmiany geometrii wyrażonej poprzez
obrót wokół centralnych wiązań C=C i C=N. Proces konwersji
wewnętrznej S1→S0 zachodzi z wysoką wydajnością
kwantową ( > 96%), co świadczy o wydajnej konwersji światła na
ciepło i potwierdza fotoprotekcyjną rolę betalain w roślinach.
Drugi zakres badań dotyczył 3H-naftopiranów – związków
wykazujących fotochromizm. Po raz pierwszy zastosowaliśmy
czasowo-rozdzielczą spektroskopię w średniej podczerwieni do
jednoznacznej identyfikacji form barwnych transoid-cis
powstających w procesie fotochromowym.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/460/
Data: środa 16.01.2019, godz. 13.00
Prelegenci: Dr Bartłomiej Guzowski i Dr inż. Roman Gozdur
Afiliacja: Katedra Przyrządów Półprzewodnikowych i
Optoelektronicznych, Politechnika Łódzka
Tytuł: Magnetokaloryczne konwertery energii
Streszczenie: Koszty energii stale rosną i dlatego też prowadzi się
wiele prac badawczych związanych z jej pozyskiwaniem ze źródeł
odnawialnych oraz jej odzyskiwaniem (ang. energy harvesing).
Termoelektryczne konwertery energii, zwane też termogeneratorami
(TEG) są rozwiązaniem, które umożliwia wytworzenie energii
elektrycznej z traconej energii cieplnej. Termogeneratory pracują
w oparciu o powszechnie znane efekty: Seebecka, Thomsona i
Peltiera i posiadają szereg zalet m.in. brak ruchomych części,
brak wibracji, niezawodność i możliwość miniaturyzacji. Sprawność
klasycznych TEG zależy przede wszystkim od przewodności
termicznej i rezystywności elektrycznej materiałów, z których są
one zrobione i jest ona niższa niż w przypadku innych typów
konwersji energii [1]. Dlatego też prace badawcze koncentrują się
przede wszystkim na poprawie figure of merit materiałów
termoelektrycznych. Zbyt mała sprawność klasycznych TEG sprawiła,
że obecnie trwają pracę nad rozwojem nowej generacji układów TEG
opartych o konwertery magnetokaloryczne. Koncepcje zaprezentowane
przez [2] są bardzo interesujące z punktu widzenia współczesnej
elektroniki. Wprowadzenie spinowych koców termoelektrycznych [3]
bezpośrednio do obudów układów elektronicznych może rozwiązać
problem rosnącego wytwarzania ciepła w elementach elektronicznych.
Zalety, takie jak bardzo małe rozmiary konwerterów
magnetokalorycznych, możliwość ich miniaturyzacji, potencjalnie
wyższy wskaźnik figure of merit w porównaniu do klasycznych TEG,
czynią konwertery magnetokaloryczne bardzo interesującymi w
kontekście wytwarzania energii elektrycznej z energii cieplnej.
W niniejszej prezentacji omówione zostały współczesne rozwiązania związane z konwersją energii cieplnej na energię elektryczną. Zaprezentowano rozwój klasycznych TEG oraz prace badawcze związane z dalszym wzrostem ich efektywności. W dalszej części prezentacji omówione zostały termogeneratory działające w obszarze spin caloritronics oraz wykazano ich potencjalną przewagę nad klasycznymi rozwiązaniami.
[1] A. Shakouri, Annu. Rev. Mater. Res., 41, (2011), 399–431.
[2] A. A. Kovalev and Y. Tserkovnyak, Solid State Commun., 150, (2010), 500–504.
[3] A. Kirihara, et. al., Nat. Mater.,11, (2012), 686–689.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/459/
Date: Wednesday 2019.01.9 at 13:00
Speaker: Prof. Serhii Reshetniak
Affiliation: Department of General and Experimental Physics,
National Technical University of Ukraine Ïgor Sikorsky Kyiv
Polytechnic Institute”, Kyiv, Ukraine
Title: Refraction and reflection of spin waves in inhomogeneous
magnetic media
Chair: Prof. Maciej Krawczyk
Seminar language: English
/458/
Date: Thursday 06.12.2018
Speaker: Dr. Hubert Głowiński
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, Poznań
Title: Magnetization damping in polycrystalline CoFe films
Abstract: Magnetization damping of polycrystalline thin films of
the Co25Fe75 alloy was found to be very low reaching
1×10−3 and the intrinsic damping of this alloy is even
lower achieving 5×10−4. Our study focuses on the
influence of an adjacent layer on total damping. We found that
only using Cu buffer we obtain low magnetization damping and we
confirmed low value of intrinsic damping.
Chair: Dr. hab. Aleksandra Trzaskowska
Seminar language: English
/457/
Date: Thursday 06.12.2018
Speaker: Dr. Emerson Coy (invited speaker)
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, Poznań
Title: High temperature magneto dielectric thin films with low
magnetic damping
Abstract: Here we present multiferroic
(ferromagnetic/ferroelectric) thin films of highly strained
Bi(Fe0.5Mn0.5)O3 as the only known high-temperature
magnetodielectric material with low Gilbert damping. We present
the general functional properties of the material, as well as few
previously unreported structural and functional properties.
Finally, we will show the great potential of this perovskite for
spintronic applications.
Chair: Dr. hab. Aleksandra Trzaskowska
Seminar language: English
/456/
Date: Thursday 06.12.2018
Speaker: Dr. Żaneta Świątkowska-Warkocka
Affiliation: Institute of Nuclear Physics, Polish Academy of
Sciences, Kraków
Title: Laser synthesis of composite magnetic particles
Abstract: Iron or nickel and their oxide nanoparticles have
received considerable attention due to their applications in
magnetic, electronic, pigmental, catalyst and biomedical purposes.
NiO/Ni and Fe3O4/FeO composite particles were prepared by a
pulsed laser irradiation of oxide nanoparticles dispersed in
liquid. The sizes of particles and their composition were
controlled by tuning the laser parameters, such as laser fluence
and/or irradiation time. Correlation between structure of obtained
composites and their magnetic properties will be presented.
Chair: Dr. hab. Aleksandra Trzaskowska
Seminar language: English
/455/
Thursday 06.12.2018
Speaker: Dr. Gabriel D. Chaves-O'Flynn
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, Poznań
Title: Thermal Stability of Soft Ferromagnetic Nanorings
Abstract: The thermal stability of ferromagnetic nanostructures is
mostly determined by the height of the energy barrier between two
micromagnetic configurations: a metastable state and the ground
state. Few analytical models for the magnetization profile at the
lowest barrier have been obtained. In this talk, I will present
micromagnetic simulations perform to validate one of those cases:
a model for magnetization reversal
of ferromagnetic nanorings [1].
[1] Phys. Rev. B 73, 054413 (2006)
Chair: Dr. Paweł Gruszecki
Seminar language: English
/454/
Date: Thursday 06.12.2018
Speaker: M.Sc. Szymon Mieszczak
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Driving magnetization dynamics in an ondemand magnonic
crystal via the magnetoelastic interaction
Abstract: Using spatial light interference of ultrafast laser
pulses we impulsively generate a spatial modulation of the
magnetization profile in an otherwise uniformly magnetized film,
inducing the onset of magnonic bandstructure and its unique
spatial distribution of magnetic excitations. The magnonic
behaviour is visualized by the resonant interaction of these spin
wave modes with elastics waves, which are simultaneously generated
with, and phase-locked to, the magnonic profile. Calculation of
the spin wave modal distribution in a laterally modulated
magnetization landscape, using both the Plane Wave Method and
micromagnetic simulations, provide a unified picture of the
non-trivial precessional dynamics observed in our experiment.
Chair: Dr. Paweł Gruszecki
Seminar language: English
/453/
Date: Thursday 06.12.2018
Speaker: Dr. Piotr Graczyk (invited speaker)
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, Poznań
Title: Electric-field-driven enhancement of magnetization dynamics
in magnetoelectric heterostructures
Abstract: We performed simulations of coupled
charge-spin-magnetization dynamics in magnetoelectric
heterostructure which consists of two high-permittivity
dielectrics separated by two conducting ferromagnetic layers. The
layers are magnetized either parallel or antiparallel to each
other. We show that it is possible to affect magnetization
dynamics with an ac voltage applied to such heterostructure. The
effect is driven by the field-like and anti-damping spin transfer
torques.
Chair: Dr. Paweł Gruszecki
Seminar language: English
/452/
Date: Thursday 06.12.2018
Speaker: Dr. Paweł Gruszecki
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Reflection of spin wave beams
Abstract: We present results of the theoretical investigation of
the spin wave beam reflection off the ferromagnetic film’s edge
and/or the gradually decreasing magnonic refractive index. In
particular, we demonstrate the Goos-Hanchen and the mirage effects
for spin waves. Furthermore, the scattering of the incident spin
wave beam at the edge spin waves, which causes the excitation of
secondary beams with the increased/decreased frequency, will be
discussed, as well.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/451/
Date: Thursday 06.12.2018
Speaker: Dr. hab. Jarosław W. Kłos
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Hartman effect for spin waves in exchange regime
Abstract: The Hartman effect is the wave phenomenon observed for
the wave package tunneling through the barrier where the
evanescent solutions exist. This effect is manifested by the
saturation of group delay of tunneling wave package with
increasing width of the barrier. We showed the possibility of
existence of the Hartman effect for the exchange spin waves. We
took into account the general Barnaś-Mills boundary conditions in
order to calculate the transmission of spin wave through the
anisotropy barrier.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/450/
Date: Thursday 06.12.2018
Speaker: Prof. Igor L. Lyubchanskii (invited speaker)
Title: Goos-Haenchen effect at Brillouin light scattering
Authors: Y. S. Dadoenkova (1,2), N. N. Dadoenkova (1,2), M.
Krawczyk (3), I. L. Lyubchanskii (2,4)
Addresses:
(1) Ulyanovsk State University, Ulyanovsk, Russia
(2) Donetsk Institute for Physics and Engineering of the National
Academy of Sciences of Ukraine
(3) Faculty of Physics, Adam Mickiewicz University in Poznań,
Poznań
(4) Faculty of Physics, V. N. Karazin Kharkiv National University,
Kharkiv
Abstract: The lateral shift of reflected light beam, known as
Goos-Haenchen effect, is theoretically studied for Brillouin light
scattering by acoustic phonons and spin waves for Daemon-Eshbach
geometry [1].
[1] Yuliya Dadoenkova, Nataliya Dadoenkova, Maciej Krawczyk and
Igor Lyubchanskii, Goos-Hänchen effect for Brillouin light
scattering by acoustic phonons, Optics Letters 43 (16), 3965 –
3968 (2018).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/449/
Date: Thursday 06.12.2018
Speaker: M.Sc. Mateusz Zelent
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Controlled motion of skyrmions in magnonic antidot
lattices
Abstract: Magnetic skyrmions are topologically protected
nano-meter sized chiral spin textures with an out of plane
magnetic domain at the center. Due to their various unique
features such as stability given by their topology, they are
considered as potential candidates for information carriers in
next generation data storage devices, like racetrack memory.
Therefore, it is crucial to be able to manipulate their
current-induced motion in various directions. Magnetic antidot
arrays can be used as a controller for skyrmion motion by using
properly designed sequences of electrical current pulses, which
marks a big leap toward skyrmion based devices, like logic gates,
magnonics filters or demultiplexers.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/448/
Date: Thursday 06.12.2018
Speaker: Prof. Konstatin V. Guslienko (keynote speaker)
Departament of Materials Physics, Faculty of Chemistry, University
of the Basque Country, San Sebastian
Title: Magnetic skyrmion stability and dynamics
Abstract: Magnetic skyrmion is a kind of topological soliton, a
non-trivial inhomogeneous magnetization texture on the nanoscale.
In this talk I focus on the skyrmion stability and spin
excitations in ultrathin magnetic films and cylindrical magnetic
dots. The skyrmions can be stabilized due to an interplay of the
isotropic and Dzyaloshinskii-Moriya exchange interactions,
out-of-plane magnetic anisotropy and magnetostatic interaction.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/447/
Date: Thursday 06.12.2018
Speaker: Dr. Joachim Graefe (invited speaker)
Affiliation: Max Planck Institute for Intelligent Systems,
Stuttgart
Title: Nanomagnetism in the X-Ray Spotlight
Abstract: The X-ray microscopy allows the application of powerful
spectroscopic techniques in length scales far smaller than
possible with optical microcopy. Near Edge X-ray Absorption Fine
Structure (NEXAFS) gives the possibilities to the element and
chemically sensitive imaging, while X-ray Circular Magnetic
Dichroism (XMCD) allows direct, highly sensitive detection of
sample magnetization. These contrast mechanisms at spatial
resolutions of below 15 nm, and even
better-using emergent techniques like ptychography, combined with the possibility of using the time structure of synchrotron light for pump- and- probe imaging with time resolutions of <50 ps make x-ray microscopy a powerful tool.
[1] W. Chao et al.: Nature 435 (2005) 1210.
[2] D. A. Shapiro et al.: Nature Photonics 8 (2014) 765.
[3] S. Woo et al.: Nature Materials 15 (2016) 501.
[4] K. Litzius et al.: Nature Physics 13 (2017) 170.
[5] S. Wintz et al.: Nature Nanotechnology 11 (2016) 948.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/446/
Date: Wednesday 05.12.2018
Speaker: Miłosz Zdunek
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Investigation of magnons and phonons by BLS in bilayer
substituted YIG samples We have investigated
Abstract: Surface Acoustic Waves (SAWs) and Backward Volume
Magnetostatic Spin Waves (BVMSWs) in bilayer substituted YIG
(Yttrium Iron Garnet) samples. The bottom layer is characterised
by in-plane magnetisation direction, while the top layer’s
magnetisation direction is out-of-plane. The spectra were obtained
by Brillouin Light Scattering (BLS) method for different magnetic
configurations. The dispersion relations for aforementioned waves
has been designated by analyzing the
spectral data.
This work was supported by National Science Centre of Poland Grant
No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and
Innovation Program under Marie Sklodowska-Curie Grant Agreement
No. 644348 (MagIC).
Chair: Prof. Sławomir Mielcarek
Seminar language: English
/445/
Date: Wednesday 05.12.2018
Speaker: Dr. Batłomiej Graczykowski (invited speaker)
Affiliation: NanoBioMedical Center, Adam Mickiewicz Univesity in
Poznań, Poznań
Title: Elastic properties of few nanometers thick membranes
Abstract: The performance gain-oriented nanostructurization has
opened a new pathway for tuning mechanical features of solid
matter vital for application and maintained performance.
Simultaneously, the mechanical evaluation has been pushed down to
dimensions way below 1 µm. In this work, by means of
micro-Brillouin light scattering we determine the mechanical
properties, that is, Young modulus and residual stress, of
polycrystalline few nanometers thick MoS2 membranes in a simple,
contact-less, nondestructive manner. The results show huge elastic
softening compared to bulk MoS2, which is correlated with the
sample morphology and the residual stress.
Chair: Prof. Sławomir Mielcarek
Seminar language: English
/444/
Date: Wednesday 2018.12.05
Speaker: M.Sc. Nandan Babu Kuttath Padi
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Authors: A. Trzaskowska, S. Mielcarek, , M. Zdunek, P. Graczyk, J.
W. Kłos, and M. Krawczyk
Title: Magnons and phonons in CoFeB/Au multilayer structures
Abstract: Inelastic light scattering is a powerful method to study
the dispersion relations of magnons and phonons. We determine the
dispersion relation of thermal magnons and phonons which exist in
the multilayered sample using Brillouin light scattering (BLS)
spectroscopy in CoFeB/Au multilayer deposited on the silicon
substrate with Ti and Au layers.In the backward scattering
geometry, the dispersion relations of magnons and phonons are
determined for different values of the magnetic field. The finite
element method (FEM) is used for interpretation of the
experimental results.
This work was supported by National Science Centre of Poland Grant
No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and
Innovation Program under Marie Sklodowska-Curie Grant Agreement
No. 644348 (MagIC).
Chair: Prof. Sławomir Mielcarek
Seminar language: English
/443/
Date: Wednesday 05.12.2018
Speaker: Dr. hab. Aleksandra Trzaskowska (invited speaker)
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Periodic nanostructures investigated using BLS
Abstract: Experimental and theoretical study of the phononic band
gap in the hypersonic range for thermally activated Surface
Acoustic Waves will be presented. Two dimensional phononic
crystals have been studied by the Surface Brillouin Light
Scattering. The experimental data will be compared with results of
theoretical modeling by the Finite Element Method.
Chair: Prof. Sławomir Mielcarek
Seminar language: English
/442/
Date: Wednesday 05.12.2018
Speaker: M.Sc. Filip Lisiecki (invited speaker)
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, Poznań
Title: Reprogrammability and scalability of magnonic Fibonacci
quasicrystals
Abstract: Magnonic quasicrystals exceed the possibilities of spin
waves (SW) manipulation offered by regular magnonic crystals,
because of their more complex SW spectra with fractal
characteristics. Here, we show the reprogrammability property of
1D Fibonacci magnonic quasicrystals, which allows controlling the
SWs transmission. We demonstrate this property in the structures
of different elements sizes and thus show the scalability of this
system down to the nanometer scale.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/441/
Date: Wednesday 05.12.2018
Speaker: Grzegorz Centała
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: The effect of spin wave pinning on FMR frequency in
periodic structures
Abstract: One of the greatest advantages of spin waves is high
frequency associated with low energy loss, therefore spin waves
are promising as prospective information carriers. However, the
usability of the devices based on spin waves is dependent on the
range of operating frequency. The customizable frequency range may
be achieved by changes in structural parameters, hence we consider
spin wave pinning as a relatively easy way to adjust the
frequency. Numerical calculations were made for CoFeB stripes
arranged in the horizontal plane. We checked how the change in the
width, thickness, and distance between the stripes affects the FMR
frequency.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/440/
Date: Wednesday 05.12.2018
Speaker: M.Sc. Justyna Rychły
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Theoretical studies of spin wave dynamics in planar
magnonic quasicrystals
Abstract: We have studied theoretically spin wave dynamics in
planar magnonic quasicrystals and compared obtained results with
the corresponding magnonic crystals. We have found that magnonic
quasicrystals are characterized by complex spin wave spectra of a
fractal nature and that spin waves of higher frequencies are
localized in the bulk region of an intact system. Moreover, the
lifetime of spin wave modes in magnonic crystals and magnonic
quasicrystals will be presented.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/439/
Date: Wednesday 05.12.2018
Speaker: Dr. Paweł Sobieszczyk (invited speaker)
Affiliation: Institute of Nuclear Physics, Polish Academy of
Sciences, Kraków
Title: Magnetization reversal mechanisms in nanopatterned thin
films with perpendicular magnetic anisotropy
Authors: Paweł Sobieszczyk, Michał Krupiński, Piotr Zieliński,
Marta Marszałek
Abstract: Fabrication and modeling of patterned thin films with
perpendicular magnetic anisotropy rise great interest due to their
wide applications in magnetic storage, sensors and magnonic
crystals. A good representative of such systems are well-ordered
arrays of magnetic antidots and dots based on Co/Pd multilayers,
where magnetic reversal mechanisms strongly depend on the array
geometry [1, 2]. We attempt to understand and reproduce the
observed magnetic properties and domain structure appearing in the
arrays by micromagnetic simulations performed using Mumax3
software [3]. In particular, changes in coercivity field, magnetic
anisotropy constant and magnetic domain arrangement were studied
and correlated with symmetry and size of nanostructures. The
calculations show how edge effects, defects and inhomogeneity
affect magnetization reversal and domain wall pinning mechanism,
which helps to design similar patterned systems with the specific
magnetic properties. Acknowledgments
The numerical simulations were supported in part by the PL-Grid Infrastructure.
[1] M. Krupinski, D. Mitin, A. Zarzycki, A. Szkudlarek, M.
Giersig, M. Albrecht and M. Marszałek, Magnetic transition from
dot to antidot regime in large area Co/Pd nanopatterned arrays
with perpendicular magnetization,
Nanotechnology 2017, 28, 085302.
[2] C. Banerjee, Pawel Gruszecki, J. W. Kłos, O. Hellwig, M.
Krawczyk, and A. Barman, Magnonic band structure in a Co/Pd stripe
domain system investigated by Brillouin light scattering and
micromagnetic simulations, Phys. Rev. B 96,
024421
[3]Vansteenkiste, A.; Leliaert, J.; Dvornik, M.; Helsen, M.;
Garcia-Sanchez, F.; Van Waeyenberge, B., The Design and
Verification of Mumax3. AIP Adv. 2014, 4, 107133.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/438/
Date: Wednesday 05.12.2018
Speaker: Krzysztof Szulc
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Magnetization reversal in the array of nanobars
Abstract: We investigate remagnetization in the two-dimensional
array of permalloy nanobars with periodic and Fibonacci order.
Hysteresis loops measured with magneto-optic Kerr effect
microscopy shows particular behaviour of the structure in the
magnetization reversal process. Monte Carlo simulations of
macrospins in effective field and micromagnetic simulations as
well as theoretical investigations of demagnetizing fields and
dipolar interactions complemented experimental results explaining
occurent phenomenons.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/437/
Date: Wednesday 05.12.2018
Speaker: Dr. Dominika Kuźma
Affiliation: Institute of Nuclear Physics, Polish Academy of
Sciences, Kraków
Title: Modeling of configuration switching in systems of
macrospins
Abstract: We study switching mechanisms between ferromagnetic and
antiferromagnetic (F – AF) configurations in systems of
elliptically shaped flat nanoparticles (macrospins) under a
variable applied magnetic field. Using a software based on the
dynamical matrix method we compute frequencies and the
corresponding spin profiles for the spin waves. Of special
interest are those in the gigahertz frequency region. Limits of
stability of configurations are marked by soft spin waves. We
present various possibilities of enhancing recovery of the most
stable AF configuration in a homogeneous external field.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/436/
Date: Wednesday 05.12.2008
Speaker: Prof. Piotr Zieliński (keynote speaker)
Affiliation: Institute of Nuclear Physics, Polish Academy of
Sciences, Kraków
Title: Is a discontinuous phase transition of second order
possible in magnetic systems?
Authors: P. Zieliński (1,2), D. Kuźma (1), P. Sobieszczyk(1), F.
Montoncello (3)
Addresses:
(1) Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
(2) Institute of Nuclear Physics, Cracow University of Technology, Kraków, Poland
(3) Department of Physics and Earth Sciences, CNISM Unit,
University of Ferrara, Ferrara
Abstract: A transition between group-subgroup unrelated
configurations is always discontinuous and often marked by a large
hysteresis that impedes the switching of the configurations by
varying a control parameter. This is e.g. characteristic of
martensitic phase transitions. It will be shown that in some
specific spin systems the hysteresis width may be reduced to zero
in analogy to the second order phase transitions. Possible
applications of such systems in the most efficiently switchable
devices will be discussed.
Chair: Dr. hab. Jarosław W. Kłos
Seminar language: English
/435/
Date: Wednesday 05.12.2018
Speaker: M.Sc. Vishal Vashistha
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Light channeling, bending and splitting via local
modification of interfaces of a photonic-crystal slab
Abstract: Photonics crystal slab (PC) consists of one, two, or
three dimensions periodic array structures which are widely used
for many applications in photonics such as guiding the light
(waveguide), high-quality factor cavity resonator, photonic
crystal fibers, and so on. In general, PCs are designed by
removing the certain portion of the periodic array structures
so-called defect region and this defect region is used to guide
the light. We study a new hybrid PC slab which consists of
dielectric rods coated with a thin layer of metal cap structures,
and the defect region is created by just removing the thin layer
of the metal cap. In this talk, I will present the various modes
which exists in the defect region, and I will present the
properties of different modes while propagating the light in
different shapes of the waveguide.
Chair: Prof. Igor L. Lyubchanskii
Seminar language: English
/434/
Date: Wednesday 05.12.2018
Speaker: Dr. hab. Maciej Wiesner (invited speaker)
Affiliation: Faculty of Physics, Adam Mickiewicz University in
Poznań, Poznań
Title: Can surface plasmons break symmetry in topological
insulators and graphene?
Abstract: A monolayer graphene is a perfect material allowing for
high frequency transport of electrons. Due to missing energy band
gap its application in switching devices is not possible. The only
way to open the band gap is symmetry breaking of a monolayer
graphene.Topological insulators are famous of lack of scattering
of electrons on structural defects. Topologically protected states
can be observed in samples of thickness of 2 – 7 nm where
contribution of bulk electrons bulk is limited. Fabrication of
such thin layers requires advanced techniques like MBE. To reduce
contribution of bulk electrons to surface conductivity one have to
break symmetry of the topological insulator along zdirection.
During this talk I will present results showing the effect of
symmetry breaking in both materials due to surface plasmon
generation.
Chair: Prof. Igor L. Lyubchanskii
Seminar language: English
/433/
Date: Wednesday 05.12.2018
Speaker: Prof. Vasily V. Temnov (keynote speaker)
Affiliation: Institute of Molecules and Materials of Le Mans,
CNRS, Le Mans, France
Title: Nonlinear magneto-plasmonics and Wood’s anomaly probed by
magnetic second-harmonic generation
Abstract: Angular- and wavelength-dependent magnetic second
harmonic generation (mSHG) on periodic arrays of nickel nanodimers
allowed us to identify a periodic structure acting as a
meta-surface (diffraction forbidden) at the fundamental frequency
and diffraction grating (diffraction allowed) at the double SHG
frequency and observe the purely nonlinear Wood's anomaly. Similar
measurements on magneto-plasmonic multilayers in Kretschmann
configuration are used to quantify the nonlinear phase-matching
condition and magnetic control of surface plasmon polaritons
generated at the SHG frequency.
Chair: Prof. Igor L. Lyubchanskii
Seminar language: English
/432/
Date: Wednesday 05.12.2018
Speaker: Prof. Dr. hab. Tadeusz Lulek (invited speaker)
Affiliation: Division of Mathematical Physics, Faculty of Physics,
AMU, Poznań
Title: A three-magnon qubit: an example of Galois symmetry of
Bethe pseudoparticles
Abstract: We discuss a specific Bethe Ansatz solution [1,2] of the
eigenproblem of the Heisenberg Hamiltonian for a magnetic
isotropic ring with N=7 nodes, at the centre k=0 of the Brillouin
zone, within the three-magnon sector r=3, which implements an
arithmetic qubit with the energy E=-5, and whose the basis states
are rigged string configurations. We demonstrate that this qubit
exhibits Galois symmetry, represented by the dihedral group D6
permuting six admissible state parameters of r=3 Bethe
pseudoparticles.
[1] T. Lulek, M. Łabuz, J. Milewski, and R. Stagraczyński, Physica
B550, 294 (2018)
[2] J. Milewski, B. Lulek, T. Lulek, and R. Stagraczyński, Physica
B434, 14 (2014).
Chair: Prof. Igor L. Lyubchanskii
Seminar language: English
/431/
Date: Wednesday 2018.12.05
Speaker: Prof. Adam Miranowicz
Title: Deterministic quantum nonlinear optics without photons
Authors: Anton F. Kockum (1), Adam Miranowicz (1,2), Simone De
Liberato (1,3), Salvatore Savasta (1,4), and Franco Nori (1,5)
Addresses:
(1) Theoretical Quantum Physics Laboratory, RIKEN
Cluster for Pioneering Research, Wako-shi, Saitama 351-0198,
Japan
(2) Faculty of Physics, Adam Mickiewicz University, 61-614
Poznań, Poland
(3) School of Physics and Astronomy, University
of Southampton, Southampton, United Kingdom
(4) Dipartimento di
Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze
della Terra, Universita di Messina, Messina, Italy
(5) Physics
Department, The University of Michigan, Ann Arbor, Michigan, USA
Abstract: We show how analogs of a large number of well-known
nonlinear-optics phenomena can be realized with one or more
two-level atoms coupled to one or more resonator modes in the
ultrastrong-coupling regime. Through higher-order processes, where
virtual photons are created and annihilated, an effective
deterministic coupling between two states of such a system can be
created. In this way, analogs of three-wave mixing, four-wave
mixing, higher-harmonic and -subharmonic generation (i.e., up- and
down-conversion), multiphoton absorption, parametric
amplification, Raman and hyper-Raman scattering, the Kerr effect,
and other nonlinear processes can be realized. In contrast to most
conventional implementations of nonlinear optics, these analogs
can reach unit efficiency, only use a minimal number of photons
(they do not require any strong external drive), and do not
require more than
two atomic levels [1,2,3].
[1] A. F. Kockum, A. Miranowicz, V. Macri, S. Savasta, F. Nori,
Phys. Rev. A 95, 063849 (2017), e-print arXiv:1701.05038 .
[2] R. Stassi, V. Macri, A. F. Kockum, O. Di Stefano, A.
Miranowicz, S. Savasta, and F. Nori, Phys. Rev. A 96, 023818
(2017), e-print arXiv:1702.00660
[3] A. F. Kockum, A. Miranowicz, S. De Liberato, S. Savasta, and
F. Nori, in press in Nature Reviews Physics, e-print
arXiv:1807.11636 .
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/430/
Date: Wednesday 05.12.2018
Speaker: Prof. Krzysztof Grygiel
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Anomalous rotational diffusion in electric fields
Abstract: The formulae for linear electric polarization induced by
harmonic electric field in liquids composed of rigid
noninteracting dipolar and asymmetric-top molecules in spherical
solvents are derived. The model of noninertial, anomalous
rotational Brownian motion is applied. The fractional rotational
diffusion equations are solved and time evolution of the electric
polarizability is investigated for the case when a dc-electric
field is turned off and for the stationary state case when only an
ac-field is present. Numerical analysis of the dispersion and
absorption parts of electric polarizability is performed as well
as the influence of molecular parameters on so-called Cole-Cole
plots is investigated.
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/429/
Date: Wednesday 2018.12.05
Speaker: Dr. Małgorzata Paprzycka
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Raman spectroscopy for proteins – fish collagen study
Abstract: [PDF] Modern medicine widely uses
exogenous collagen as good material for tissue regeneration, also
as natural substrate for cell attachment and proliferation, used
to create dressings and to support the treatment of burn wounds or
diabetic wounds, or finally as a source of amino acids in the diet
complementary to the body's needs [1,2]. Collagen is a safe
material that has a high biocompatibility and biodegradability and
good cell adhesion [3]. Due to the possibility of transferring
Creutzfeld-Jacob disease(Bovine Spongiform Encephalopathy) from
animals to the human body, the interest in collagen from fish
increased. The collagen we examined comes from the skin of silver
carp fish (Hypophtalmichthys molitrix), and was obtained by method
of hydration in an aqueous lactic acid solution [4]. The
topography of the test sample was made with The Dimension® Icon™
Scanning Probe Microscope (SPM), showing its fibrillar structure,
with dimensions equivalent to those shown in the literature [5].
Raman spectroscopy was used to study fish collagen using a
Renishaw Ramascope 1000 spectrometer. The source of the
excitations was a helium-neon laser with a wavelength of 633 nm.
Analysis of Raman spectra allowed to determine the content of
amino acids in collagen, including glycine, proline and
hydroxyproline. It also showed the native nature of the material
at 200C. The durability of the secondary structure of this
material heated to about 900C and cooled was also proved. Raman
spectroscopy has been presented as an effective method for testing
biopolymers [6].
[1] Sanz M and all, Clinical Evaluation of a New collage matrix (mucograpf prototype) to enhance the wight of keratinized tissue In patients with fixed prosthetic restorations: a randomized prospective clinical trial. J. Clin Periodontol. 2009; 36 (10), 868-876.
[2] Ghanaati S et al, Evaluation of the tissue reaction to a new bilayered collagen matrix in vivo and its translation to the clinic. Biomed Mater. 2011(1); 015010.
[3] Sionkowska A. Current reaserch on the blends of natural and synthetic polymers as new biomaterial: review. Progress in Polimer science, 2011; 36: 1254-1276.
[4] Przybylski J.E., Patent US 7285638, B2 (2007).
[5] Buehler M.J., Nature designs tough collagen: Explaining the
nanostructure of collagen fibrils, Proceedings of the National
Academy of Sciences Aug 2006, 103 (33) 12285-12290.
[6] Paprzycka M, Scheibe B, Jurga S, Fish collage – molecular
structure after thermal treatment, Fibres & Textile In Eastern
Europe, 132, 2018.
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/428/
Date: Wednesday 2018.12.05
Speaker: Prof. Waldemar Głaz
Affiliation: Nonlinear Optics Division, Physics Faculty, Adam
Mickiewicz University, Poznań, Poland
Title: Ab initio vs model extended techniques of computing linear
and nonlinear collisional polarizabilities in H2-H
supermolecules.
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/427/
Date: Wednesday 2018.12.05
Speaker: Prof. Jan Peřina Jr. (keynote speaker)
Title: Auto-ionization in the presence of a neighbor atom
Authors: J. Peřina1, Jr., W. Leoński2, A. Luks1, V.
Peřinová1
Addresses:
1Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Science of the
Czech Republic, Olomouc, Czech Republic
2 Quantum Optics
and Engineering Division, Institute of Physics, University of
Zielona Góra, Zielona Góra, Poland
Abstract: Long-time photoelectron ionization spectra of a system
with an auto-ionizing level interacting with a neighbor two-level
atom are discussed. These spectra are typically composed of
several peaks. Conditions for the occurrence of Fano and Fano-like
zeros are revealed. Photoelectron ionization spectra conditioned
by the measurement on the two-level atom show oscillations at the
Rabi frequency of the neighbor two-level atom. The presence of
spectral dynamical zeros in the conditioned spectra is predicted.
Also entanglement between an ionized electron and that bound on
the two-level system is analyzed using negativity. Two-dimensional
spectral density of negativity is defined to identify spectrally
local entanglement between two electrons. It reveals that
entanglement is 'concentrated' around spectral peaks.
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/426/
Date: Wednesday 2018.12.05
Speaker: Dr. Natalia Kielich-Buchowska
Affiliation: Faculty of Law and Administration, Adam Mickiewicz
University, Poznań, Poland
Title: Memories of Prof. Stanisław Kielich (invited talk)
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/425/
Date: Wednesday 2018.12.05
Speaker: Prof. Ryszard Tanaś
Affiliation: Nonlinear Optics Division, Physics Faculty, Adam
Mickiewicz University, Poznań, Poland
Title: Memories of Prof. Stanisław Kielich
Abstract: In my talk I would like to remind some historical facts
from the biography of Professor Stanisław Kielich related to the
beginning and progress of nonlinear optics in Poznań.
Chair: Prof. Krzysztof Grygiel
Seminar language: English
/424/
Date: Tuesday 2018.12.04, 13:00
Speaker: Prof. Jan Peřina Jr.
Authors: Jan Peřina Jr., O. Haderka, V. Michalek, and I. I.
Arkhipov
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Science of the Czech
Republic, Olomouc, Czech Republic
Title: Experimental photon counting with weak twin beams
Abstract: Investigations of mesoscopic twin beams containing
typically several photon pairs using an iCCD camera with
single-photon resolution will be discussed. Operation of the
camera as a photon-number-resolving detector endowed with spatial
resolution will be analyzed. Different types of reconstructions of
the joint signal-idler photon-number distributions of twin beams
will be discussed including the method of maximal likelihood and
that assuming a multimode Gaussian form of in general noisy twin
beams. Also the use of spatial correlations inside twin beams for
reducing the noise in the experimental data and subsequent
less-noisier reconstruction of the joint photon-number
distribution will be mentioned. Reconstruction of the joint
signal-idler quasi-distributions of integrated intensities will be
discussed. Different types of nonclassicality (entanglement)
criteria written in terms of integrated-intensity moments as well
as using directly the elements of photon-number distributions will
be introduced. The method of absolute detector calibration
principally based on pairing of photons in twin beams will be
presented. Postselection by photon-number-resolving detection as a
tool for generating (higher-order) sub-Poissonian states of light
will be discussed based on the experimental results.
Chair: Prof. Adam Miranowicz
Seminar language: English
/423/
Date: Wednesday 2018.11.28
Speaker: Dr. hab. Anna Kowalewska-Kudłaszyk
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Photon blockade via squeezing
Abstract: Single photon generation can be obtained either in
optical systems with strong single-photon nonlinearities
(conventional photon blockade) or in the systems with extremely
weak optical nonlinearities (unconventional photon blockade). Such
photon blockades are associated with sub-Poissonian statistics and
strong antibunching. We will discuss possibility of observing
single, multiphoton and non-standard blockades with squeezed
states. An example of dissipative squeezing interactions will be
given.
Chair: Dr. hab. Jan Soubusta
Seminar language: English
/422/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Shilan Ismael Abo
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Photon-phonon blockade
Abstract: Many applications in quantum technologies, such as
quantum cryptography or optical quantum information processing,
require light sources with a precise number of photons. Photon
(phonon) blockade is the quantum phenomenon that occurs in a
driven nonlinear system, in which a single photon (phonon) in the
system prohibits the generation or entry of other photons
(phonons) to the system. These effects are described by the
sub-Poissonian excitation-number statistics. Here we describe
cases such that a combined photon-phonon mode exhibits
sub-Poissonian statistics, while each mode, if analyzed
separately, exhibits super-Poissonian statistics.
Chair: Dr. hab. Jan Soubusta
Seminar language: English
/421/
Date: Wednesday 2018.11.28
Speaker: Dr. Ievgen I. Arkhipov
Affiliation: Joint Laboratory of Optics of Palacky University and
Institute of Physics of CAS, Olomouc, Czech Republic
Title: Revealing nonclassicality of Gaussian states of light
Abstract: We present a method that allows one to completely reveal
nonclassicality of Gaussian states of light, initially generated
in optical spontaneous parametric processes, by means of an
appropriately induced stimulated emission. Namely, we exploit the
fact that stimulating fields in stimulated emission processes for
Gaussian states play the role of displacing coherent fields,
which, therefore, by no means affect nonclassicality of initially
generated Gaussian states. Then, by utilizing a certain
nonclassicality criterion, which is expressed in terms of
integrated intensity moments of optical fields up to the second
order, we show that one can truly certify the presence of quantum
correlations of such Gaussian states by varying the complex
amplitude of stimulating coherent fields.
Chair: Dr. hab. Jan Soubusta
Seminar language: English
/420/
Date: Wednesday 2018.11.28
Speaker: Dr. Karol Bartkiewicz
Affiliations: (1) Nonlinear Optics Division, Physics Faculty, AMU,
Poznań and (2) RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of the
Czech Republic, Faculty of Science, Palacký University, Czech
Republic
Title: Measuring distance between points in Hilbert space with
photons
Abstract: The quantum properties of polarisation-correlated photon
pairs like, e.g., quantum entanglement, purity etc. make them a
powerful resource in quantum communication, including quantum key
distribution protocols. These properties and their quantifiers,
which can be defined in terms of distances in Hilbert space, are
usually measured indirectly by first performing complete quantum
state tomography and then calculating their value from the
reconstructed density matrices. In many cases this procedure
requires performing more measurements than necessary to
characterise the investigated quantum property and it tells little
about the nature of the characterised property. I will explain how
to directly measure the distance between points in Hilbert space
using single photons, the maximal level of Bell inequality
violation, a universal entanglement witness and the negativity of
an arbitrary two-photon polarisation state by only two-photon
interference of photons assorted from a few (at most four) copies
of the investigated state. I will discuss the experimental
challenges and limitations of this approach as well as the
possible solutions within the framework of linear optics.
[1] Bartkiewicz, K., Horst, B., Miranowicz, A., "Entanglement estimation from Bell inequality violation," Phys. Rev. A 88, 052105 (2013).
[2] Bartkiewicz, K., Lemr, K., Černoch, A., Miranowicz, A, "Bell nonlocality and fully entangled fraction measured in an entanglement-swapping device without quantum state tomography," Phys. Rev. A 95, 030102R (2017).
[3] Bartkiewicz, K., Horodecki, P., Lemr, K., Miranowicz, A., Życzkowski, K., "Method for universal detection of two-photon polarization entanglement," Phys. Rev. A 91, 032315 (2015).
[4] Bartkiewicz, K., Beran, J., Lemr, K., Norek, M., Miranowicz, A., "Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix," Phys. Rev. A 91, 022323 (2015).
[5] Bartkiewicz, K., Chimczak, G., Lemr, K., "Direct method for measuring and witnessing quantum entanglement of arbitrary two-qubit states through Hong-Ou-Mandel interference, " Phys. Rev. A 95, 022331 (2017).
[6] Bartkiewicz, K., Chimczak., "Two methods for measuring Bell nonlocality via local unitary invariants of two-qubit systems in Hong-Ou-Mandel interferometers," Phys. Rev. A 97, 012107 (2018).
[7] Bartkiewicz, K., Lemr, K., Černoch, A., Soubusta, J., "Measuring nonclassical correlations of two-photon states," Phys. Rev. A 87, 062102 (2013).
[8] Trávníček, V., Bartkiewicz, K., Černoch, A., Lemr. K., "Experimental measurement of a nonlinear entanglement witness by hyperentangling two-qubit states," Phys. Rev. A 98, 032307 (2018).
Chair: Dr. hab. Karel Lemr
Seminar language: English
/419/
Date: Wednesday 2018.11.28
Speaker: Dr. Antonín Černoch (invited speaker)
Affiliation: Joint Laboratory of Optics of Palacký University and
Institute of Physics of Academy of Sciences of the Czech Republic,
Faculty of Science, Palacký University, Olomouc, Czech Republic
Title: Beam-splitting tricks
Abstract: Beam-splitter is a very common component of setups for
quantum information experiments. The quality of measurement
results strongly depends on its parameters especially on splitting
ratio. In this talk some tricks how to fine tune the splitting
ratio will be shown.
Chair: Dr. hab. Karel Lemr
Seminar language: English
/418/
Date: Wednesday 2018.11.28
Speaker: Dr. hab. Jan Soubusta (invited speaker)
Title: Experimental testing of three-qubit nonlocality
Authors: Artur Barasiński (1,2), Antonín Černoch (2), Karel Lemr
(2), and Jan Soubusta (2)
Addresses:
(1) Institute of Physics, University of Zielona Góra, Poland
(2) Joint Laboratory of Optics of Palacky University and Institute
of Physics of Czech Academy of Sciences, 771 46 Olomouc, Czech
Republic
Abstract: [PDF] We are used to the fact that all
bipartite pure entangled quantum states violate a Bell inequality.
This means that measurement results on this quantum system
manifest nonlocal correlations. So far the relationship between
entanglement and nonlocality is still a subject of an intense
study. Recently a new measure of nonlocality was proposed [1]. It
is defined as the probability, that the pure state will display
nonlocal correlation when subjected to random measurements. When
scanning over all possible projection measurements, we can define
a nonlocal volume, which corresponds to the subspace in which the
projection measurements prove nonlocality of the input state. We
decided to test these relations for three-qubit states,
generalized Greenberger-Horne-Zeilinger (gGHZ) states [2]. It was
recently shown that the nonlocal volume has very convenient
properties. For example, for pure states this measure is monotonic
with entanglement described by the gGHZ angle. The more the state
is entangled, the larger is the probability to violate Bell
inequalities selecting random measurements. For this purpose we
first had to build an efficient experimental setup, that is
capable to generate the gGHZ states. states and to carry out the
optimal measurements very fast. Secondly, we have experimentally
verified numerical simulations of optimal measurements proposed to
detect the greatest violation of several Bell-type inequalities
for three-partite states [3, 4]. Finally, we have started detailed
experimental mapping of the projection measurement space to get
the nonlocal volume of the tested states. We hope that this both
theoretical end experimental research can help to get better
insight into the abstract quantities characterizing quantum states
and also to the mutual relationship between them [5, 6].
[1] V. Lipińska, F. J. Curchod, A. Mattar, and A. Acin, New J. Phys. 20, 063043 (2018).
[2] D. M. Greenberger, M. A. Horne, A. Shimony, and A. Zeilinger, Am. J. Phys. 58, 1131 (1990).
[3] G. Svetlichny, Phys. Rev. D 35, 3066 (1987).
[4] J.-D. Bancal, J. Barrett, N. Gisin, and S. Pironio, Phys. Rev. A 88, 014102 (2013).
[5] I. Arkhipov, A. Barasiński, and J. Svozilik, Sc. Rep. 8, 16955 (2018).
[6] A. Barasiński, Sc. Rep. 8, 12305 (2018).
Chair: Dr. hab. Karel Lemr
Seminar language: English
/417/
Date: Wednesday 2018.11.28
Speaker: Dr. Grzegorz Chimczak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU,
Poznań
Title: Four-level diamond-type atom as a field-field coupler
Abstract: We present engineering a fully controllable effective
coupling between two quantized cavity modes via an ensemble of
four-level atoms in the diamond configuration. This controllable
effective coupling makes it possible to transfer coherent
superpositions of cavity-mode number states from one mode to the
other on demand. We also show that despite the fact that the
system is complex, it is possible to describe its evolution using
a simple effective Hamiltonian.
Chair: Prof. Wiesław Leoński
Seminar language: English
/416/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Mateusz Nowotarski
Title: Entanglement properties of highly symmetric qudit states
Authors: Mateusz Nowotarski (1) and Artur Barasiński (1,2)
Addresses:
(1) Quantum Optics and Engineering Division, Institute of Physics,
University of Zielona Góra, Z. Szafrana 4a, 65-516 Zielona Góra,
Poland
(2)RCPTM, Joint Laboratory of Optics of Palacky University and
Institute of Physics of Academy of Sciences of the Czech Republic,
17. Listopadu 12, 772 07 Olomouc, Czech Republic
Abstract: Quantum entanglement plays an important role in quantum
theory as one of the most unintuitive physical phenomenons.
Because of many possible applications, characterization of quantum
states is an important task. While the calculation of entanglement
measures for pure two-qudit states is not challenging, it becomes
significantly much more complicated in case of mixed two-qudit
states. The basic approach to this problem is restriction the
specific subgroup of states which obey specific symmetrical
conditions. Here we discus a recently introduced highly symmetric
qudit states family with incomplete permutation symmetry [1, 2]
This family consists of both pure and mixed states and can be
described by five real parameters. For those states we perform
extensive analysis of various conditions of separability and
entanglement classification. Furthermore our results can be used
for any arbitrary quantum state by application of twirling
operator.
[1] A. Barasiński and M. Nowotarski, Phys. Rev. A 94, 062319
(2016)
[2] A. Barasiński and M. Nowotarski, Phys. Rev. A 95, 042333
(2017)
Chair: Prof. Wiesław Leoński
Seminar language: English
/415/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Izabela Domagalska
Title: The influence of a charge asymmetry of cores on the
physical state of the positively charged molecule ion.
Authors: Izabela A. Domagalska (1), Marcin W. Jarosik (2),
Radosław Szczęśniak (2), Joanna K. Kalaga (1)
Addresses:
(1) Quantum Optics and Engineering Division, Institute of Physics,
University of Zielona Góra, Zielona Góra, Poland
(2) Institute
of Physics, Częstochowa University of Technology, Częstochowa,
Poland
Abstract: We have analyzed the dynamics of the positively charged
ion of a diatomic molecule, in which the atomic cores are under
the influence of an external force of harmonic-type which is
explicitly dependent on the amplitude and frequency. The ground
state of the ion has been determined using the variational method.
The influence of charge core asymmetry on such state energy and
the filling of ion nodes has been calculated. We have also
verified how the charge asymmetry of the cores affects the value
of the Lyapunov exponent.
Chair: Prof. Wiesław Leoński
Seminar language: English
/414/
Date: Wednesday 2018.11.28
Speaker: Dr. Joanna Kalaga (invited speaker)
Title: Generation of squeezed states in a quantum-chaotic system
Authors: J. K. Kalaga (1,2), W. Leoński (1,2), M. W. Jarosik (3),
and R. Szczęśniak (3)
Addresses:
(1) Quantum Optics and Engineering Division, Faculty of Physics
and Astronomy, University of Zielona Góra, Zielona Góra, Poland
(2) Joint Laboratory of Optics of Palacký University and Institute
of Physics of CAS, Faculty of Science, Palacký University,
Olomouc, Czech Republic
(3) Institute of Physics, Częstochowa University of Technology,
Częstochowa, Poland
Abstract: Analysis of quantum dynamics of the systems which
classical counterparts exhibit chaotic behavior seems to be one of
the most intriguing topics related to the quantum dynamics'
research. In particular, finding the methods allowing detection of
the appearance of the quantum chaos is especially intriguing. We
consider here the application of the normally ordered variances of
the quadratures operators as a witness of quantum-chaotic
evolution. We discuss them in a context of the anharmonic
Kerr-like oscillator excited by a series of ultra-short coherent
pulses.
Chair: Prof. Wiesław Leoński
Seminar language: English
/413/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Marcin Karczewski
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Monogamy of Particle Statistics in Tripartite Systems
Simulating Bosons and Fermions
Abstract: In the quantum world, correlations can take the form of
entanglement which is known to be monogamous. Following Phys. Rev.
Lett. 121, 090403 (2018), we will argue that another type of
correlation, indistinguishability, is also restricted by some form
of monogamy. Namely, if particles A and B simulate bosons, then A
and C cannot perfectly imitate fermions. The main point of this
talk consists in demonstrating to what extent it is possible.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/412/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Zakarya Lasmar
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: On composite behaviour of complex quantum systems:
sometimes entanglement needs to be backed by interaction
Abstract: It was recently suggested that two entangled fermions
can behave like a single boson and that the bosonic quality is
proportional to the degree of entanglement between the two
particles. The relation between bosonic quality and entanglement
is quite natural if one takes into account the fact that
entanglement appears in bound states of interacting systems.
However, entanglement can still be present in spatially separated
subsystems that do not interact anymore. These systems are often a
subject of studies on quantum nonlocality and foundations of
quantum physics. In the first half of this talk, I will discuss
whether an entangled spatially separated fermionic pair can
exhibit bosonic properties. I will consider certain conditions
under which the answer to this question can be positive. In
addition, I will present a nonlocal bunching scenario in which two
of such pairs form an analogue of a two-partite bosonic Fock
state. In the second half of this talk, I will present our new
findings regarding the behaviour of a system of N identical pairs
of fermions within the Hubbard model. I will show that with
certain types of interaction, the ground state of this system will
be reduced to an N-partite bosonic Fock state.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/411/
Date: Wednesday 2018.11.28
Speaker: Dr. hab. Paweł Kurzyński
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Evolution of negative probability distributions
Abstract: There is an intriguing idea that quantum theory would be
recovered if standard probabilities were replaced by negative
probabilities and some events were deemed unobservable. However,
such approach would be able to recover only one half of quantum
theory - state description and measurement. The other half of the
theory describes how states change in time. In this presentation I
will discuss which evolutions of negative probability
distributions are allowed. It is known that the evolution of
standard probability distributions is determined by stochastic
matrices, which generate either simple reversible permutations, or
fundamentally irreversible dynamics. On the other hand, the
evolution of negative probability distributions can be described
by pseudo-stochastic matrices, i.e., matrices whose entries are
given by negative probabilities. These matrices give rise to a
much richer dynamics in which there are nontrivial reversible
transformations.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/410/
Date: Wednesday 2018.11.28
Speaker: Prof. Andrzej Grudka
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Time travel and the Second Law of Thermodynamics
Abstract: One of the most surprising predictions of general
relativity is possibility of time travel into one’s past. These so
called closed timelike curves lead to the grandfather paradox.
However Deutsch and also Bennett and Schumacher proposed quantum
models which avoid this paradox. In this talk we show what are
implications of these models to the Second Law of Thermodynamics.
Chair: Prof. Ryszard Tanaś
Seminar language: English
/409/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Vojtěch Trávníček
Affiliation: Joint Laboratory of Optics of Palacký University,
Olomouc, Czech Republic
Title: Experimental measurement of nonlinear entanglement witness
by hyper-entangling two-qubit states
Abstract: We demonstrate that non–linear entanglement witnesses
can be made particularly useful for en- tanglement detection in
hyper–entangled or multilevel states. We test this idea
experimentally on the platform of linear optics using a
hyper–entangled state of two photons. Instead of several
simultaneous copies of two-photon entangled states, one can
directly measure the witness on single copy of a hyper–entangled
state. Our results indicate that hyper–entanglement can be used
for quick entanglement detection and it provides a practical
testbed for experiments with non–linear entanglement witnesses.
Chair: Prof. Adam Miranowicz
Seminar language: English
/408/
Date: Wednesday 2018.11.28
Speaker: M.Sc. Kateřina Jiráková (Olomouc)
Title: Experimental counterfeiting of quantum money
Authors: Kateřina Jiráková (1*), Karol Bartkiewicz (2,1), Antonín
Černoch (3), and Karel Lemr (1)
Addresses:
(1) RCPTM, Joint Laboratory of Optics of Palacký University and
Institute of Physics of Academy of Sciences of the Czech Republic,
Olomouc, Czech Republic
(2) Faculty of Physics, Adam Mickiewicz University,
Poznań, Poland
(3) Institute of Physics of Academy of Sciences of the Czech
Republic, Joint Laboratory of Optics of PU and IP AS CR,
Olomouc, Czech Republic
(*) Presently on leave at Faculty of Physics, Adam Mickiewicz
University, Poznań, Poland
Abstract: The concept of quantum money has been originally
suggested by S. Wiesner in the 1970s. Its main advantage is that
every attempt to copy quantum banknotes leaves the quantum states
changed providing a mark on money counterfeits. According to the
no-cloning theorem the quantum states cannot be in general
perfectly cloned (copied). However, an imperfect cloning is still
possible. We present a version of an eavesdropping attack on the
protocol proposed by Bozzio et al. (2018). The aim of our research
is to demonstrate that cloning implemented even rarely enough that
it is indistinguishable from noise is fully sufficient to acquire
useful information to counterfeit quantum banknotes. We exploit
the fact that completely random encoding of quantum banknotes is
computationally impractical and that the bank needs to select a
non-random but secret encoding algorithm. Data analysis or machine
learning allow the attacker to discover bank’s secret and thus
predict future banknotes merely on the basis of partial
information gained by cloning of previous banknotes.
Chair: Prof. Adam Miranowicz
Seminar language: English
/407/
Date: Wednesday 2018.11.28
Speaker: Dr. hab. Karel Lemr (invited speaker)
Affiliation: Joint Laboratory of Optics of Palacký University and
Institute of Physics of Academy of Sciences of the Czech Republic,
Faculty of Science, Palacký University, Olomouc, Czech Republic
Title: Diagnosing quantum relays by means of collective
entanglement witnesses
Abstract: The talk discusses the possibility to use collective
entanglement witnesses, namely the collectibility, in quantum
relay diagnostics. Theoretical concept as well as an experimental
implementation shall be presented. The talk promotes benefits of
this idea by comparing its experimental requirements with
previously used methods.
Chair: Prof. Adam Miranowicz
Seminar language: English
/406/
Date: Wednesday 2018.11.28
Speaker: Prof. Wiesław Leoński (keynote speaker)
Affiliation: Quantum Optics and Engineering Division, Institute of
Physics, University of Zielona Góra, Zielona Góra, Poland
Title: Quantum steering in a system of three qubits – some remarks
and findings
Abstract: We discuss a system of three qubits and concentrate on
the quantum steering effect appearing in such a system. In
particular, we discuss the relations of the steering with the
other form of quantum correlations, the quantum entanglement
[1,2]. Additionally, we present how the interesting us effects can
appear in the three-mode triangle Bose–Hubbard system [3].
[1] J. K. Kalaga, W. Leoński, Quant. Inf. Process. (2017) 16:175
[2] J. K. Kalaga, W. Leoński, J. Perina Jr., Phys. Rev. A (2018) 97:042110
[3] J. K. Kalaga, W. Leoński, R. Szczęśniak Quant. Inf. Process.
(2017) 16:265
Chair: Prof. Adam Miranowicz
Seminar language: English
/405/
Date: Wednesday 2018.11.28
Speaker: Prof. Ryszard Tanaś (keynote speaker)
Affiliation: Nonlinear Optics Division, Physics Faculty, Adam
Mickiewicz University, Poznań, Poland
Title: Violation of monogamy relations for negativity in a
three-atom system
Abstract: Quantum correlations in multi-qubit systems are subject
of intensive studies because of their crucial role in quantum
information processing. Probably the most popular measure of
correlations is entanglement, but there are other measures that
have been introduced and studied, such as quantum discord,
geometric quantum discord, measurement induced disturbance and
others. The simplest bipartite system in which the correlations
can be studied is a system of two qubits, or two two-level atoms.
In case of two-level atoms interacting with the reservoir of
electromagnetic field modes in the vacuum, the evolution of the
system can be described by the well known Lehmberg-Agarwal master
equations. The collective evolution of the two-atom system depends
on two collective parameters: collective damping 12 and
dipole-dipole interaction γ12, which both depend on the
interatomic distance. Such a system is a good testing ground for
studying evolution of quantum correlations. We study a more
complex system of three-atoms embedded in a common vacuum. Such a
system is more difficult to describe because, for mixed states, we
deal with 8×8 matrix which leads to 63 equations, and, what
is even worse, there are no formulas to calculate concurrence,
even if we know all the matrix elements. Fortunately, it is
possible to calculate negativity, which is another measure of
entanglement. Concurrence and negativity give the same values for
pure states, but are different for mixed states. So, we use
negativity as a measure of entanglement in a three-atom system.
Master equation for the density matrix is solved, and we find
evolution of the negativity in a three-atom system. The evolution
depends on the collective parameters γij and
Ωij. We test, in particular, the so called monogamy
relations for negativity, for chosen initial states of the system.
It is shown that for some states monogamy relations are violated.
Chair: Prof. Adam Miranowicz
Seminar language: English
/404/
Date: Monday 2018.11.26 at 13:00
Speaker: Prof. Oleksandr V. Dobrovolskiy
Affiliation: Physics Department, V. N. Karazin Kharkiv National University, Ukraine, and
Physikalisches Institut, Goethe University Frankfurt am Main,
Germany
Title: Spin-wave phase inverter upon a single nanodefect
Chair: Prof. Maciej Krawczyk
Seminar language: English
/403/
Date: Wednesday 2018.11.14 at 13:00
Speaker: M.Sc. Karol Gietka
Affiliation: Katedra Optyki Kwantowej i Fizyki Atomowej, Instytut
Fizyki Teoretycznej Uniwersytetu Warszawskiego
Title: Quantum metrology beyond entanglement and measurement
Abstract: During the seminar, I will give a short introduction to
quantum metrology, which, generally speaking, aims at enhancing
the sensitivity of measurement beyond the classical limit of
precision. One of the most exciting aspects of quantum metrology
is the possibility to harness entangled states of many-body
quantum systems. On the example of a two-mode Bose-Einstein
condensate, I will show how to generate such states and use them
subsequently in the process of estimating an unknown parameter. I
will explain why entangled states can enhance the sensitivity of
measurement and why the use of them is currently restricted to
proof-of-principle experiments. To overcome this limitation, I
will show an alternative way (without entanglement) of enhancing
the sensitivity by exploiting features of an exotic state of
matter known as supersolid. Finally, I will show how one of the
central theoretical tools in quantum metrology, quantum Fisher
information, can be used to study quantum chaos.
Chair: Prof. Adam Miranowicz
Seminar language: English
/402/
Data: środa 2018.11.7
Prelegent: Dr. Kacper Drużbicki
Afiliacja: Zakład Radiospektroskopii, Wydział Fizyki UAM
Tytuł: Obliczenia periodyczne w formalizmie DFT jako narzędzie
wspomagające badania struktury i własności dynamicznych kryształów
molekularnych (seminarium habilitacyjne)
Streszczenie: Współczesna krystalografia stanowi podstawowe narzędzie
badania struktury kryształów molekularnych. Statyczny obraz
struktury średniej kryształu, definiowanej przez uporządkowanie
dalekiego zasięgu, ma bez wątpienia znaczenie fundamentalne, jest
on jednak obrazem niepełnym. Spojrzenie na kryształy molekularne z
alternatywnej perspektywy, tj. lokalnego otoczenia molekuły,
pozwala uzupełnić naszą wiedzę na temat struktury i dynamiki sieci
krystalicznej oraz rządzących nią oddziaływań. W tym kontekście,
metody spektroskopii ciała stałego stanowią nieodzowne narzędzie
badawcze, gdzie spektroskopia jądrowego rezonansu magnetycznego,
NMR, może być uznana za metodę wiodąca prym. Rozwój spektroskopii
NMR doprowadził do zaproponowania koncepcji krystalografii NMR,
uznanej powszechnie jako pełnowartościową metodę badań
strukturalnych. W referacie przedstawiona zostanie analiza
możliwości wykorzystania wspieranych-obliczeniowo metod
komplementarnych do NMR w badaniach kryształów molekularnych
wykazujących różny stopień nieporządku. Bazując głównie na
metodach spektroskopii neutronowej, przedstawione zostaną
przykłady badań układów o znaczeniu zarówno poznawczym (kryształy
molekularne z wiązaniem wodorowym) jak i aplikacyjnym (substancje
farmaceutyczne oraz perowskitowy materiał fotowoltaiczny).
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/401/
Date: Friday 2018.10.12
Speaker: prof. Mitsuteru Inuoe
Affiliation: Toyohashi University of Technology, Japan; 2018
Distinguished Lecturer of IEEE Magnetics
Title: Magnetic Phase Interference in Artificial Magnetic
Lattices: Functions and Applications to Optical, High-Frequency,
and Spin Wave Devices
Abstract: The introduction of artificial magnetic structures into
magnetic materials can induce novel electromagnetic and spin-wave
behavior. Nano- and submicrometer-scale artificial magnetic
lattices (AMLs) can control optical (electromagnetic) waves in
magnetophotonic crystals [1], volumetric magnetic holograms [2],
and labyrinthian magnetic domain structures [3], and can affect
spin waves in magnonic crystals [4]. In this talk, the fundamental
properties of such AMLs, mainly in magnetic garnet films and alloy
thin films, are discussed, followed by demonstrations of their
applications in optical and spin-wave micro-devices driven by
magnetic phase interference: volumetric magneto-optic (MO)
hologram memories [2] and three-dimensional MO holographic
displays [5] with magnetophotonic crystals; high-speed MO Q-switch
micro-chip lasers with iron-garnet films with labyrinthian
magnetic domain structures [3]; and highly sensitive magnetic
sensors and spin-wave logic circuits with magnonic crystals [6].
Prospective future spin-wave devices with AMLs will be discussed in the context of the new paradigm of magnonics (electron non-transport electronics), where spin waves play an important role as the information carrier.
[1] T. Goto et al., “Magnetophotonic crystal comprising electro-optical layer for controlling helicity of light,” J. Appl. Phys., vol. 111, 07A913, 2012.
[2] Y. Nakamura et al., “Error-free reconstruction of magnetic hologram via improvement of recording conditions in collinear optical system,” Optics Exp., vol. 25, pp. 15349-15357, 2017.
[3] R. Morimoto et al., “Magnetic domains driving a Q-switched laser,” Sci. Rep., vol. 6, 38679, 2016.
[4] N. Kanazawa et al., “Metal thickness dependence on spin wave propagation in magnonic crystal using yttrium iron garnet,” J. Appl. Phys., vol. 117, 17E510, 2015.
[5] K. Nakamura et al., “Improvement of diffraction efficiency of
three-dimensional magneto-optic spatial light modulator with
magnetophotonic crystal,” Appl. Phys. Lett., vol. 108, 022404,
2016.
Biography: Mitsuteru Inoue received the B.S. degree in information engineering and the M.S. and DrEng. degrees in electrical and electronic engineering in 1981, 1983, and 1989 from Toyohashi University of Technology (TUT), Japan. He was an associate professor at TUT from 1993 to 1996, and with the Research Institute of Electrical Communication, Tohoku University, from 1997 to 1999. From 2001 to 2013 he served as professor in the Department of Electrical and Electronic Engineering, TUT. Since 2014 he is jointly serving as professor of the Graduate School of TUT and as an executive trustee and vice president of TUT. He was a visiting professor at Stanford University in 2003 and at Moscow State University in 2004.
His research interests include spin-coupled wave propagation phenomena in amorphous alloy and magnetic garnet thin films, including phase modulation of magneto-surface-acoustic-waves, control and phase modulation of optical waves, and control of high-frequency magnetostatic and spin waves, together with their applications in magneto-optical (MO) spatial light modulators, three-dimensional MO displays, non-destructive MO imaging, magnetic hologram recording, and spin-wave logic circuits.
Prof. Inoue has served as the director of Magnetics Society of
Japan from 2013 to 2015 and as the general chair of the Magnetics
and Optics Research International Symposium (MORIS, 2015 and
2018). He is currently the chair of the 147th Committee on
Amorphous and Nano-Crystalline Materials of the
University-Industry Cooperative Research Committees, Japan Society
for the Promotion of Science (JSPS). [copied from
ieeemagnetics.org]
Chair: Prof. Maciej Krawczyk
Seminar language: English
/400/
Data: środa 2018.10.03
Prelegent: Dr. Mateusz Kempiński
Afiliacja: Zakład Fizyki Dielektryków, Wydział Fizyki UAM
Tytuł: Zjawiska transportu i lokalizacji nośników ładunku w
układach grafenowych i grafeno-podobnych (Seminarium
habilitacyjne)
Streszczenie: Opisywane osiągnięcie naukowe dotyczy badań nad
transportem i lokalizacją nośników ładunku i spinu w układach,
których podstawową jednostką strukturalną jest płaszczyzna
grafenowa. Badano dwie klasy materiałów: tlenki grafenu (o różnej
zawartości tlenu w strukturze) oraz aktywowane włókna węglowe (o
różnej porowatości). W prezentowanych badaniach użyte zostały trzy
techniki badawcze: elektronowy rezonans paramagnetyczny,
spektroskopia impedancyjna oraz stałoprądowy pomiar oporu
elektrycznego, wsparte obrazowaniem mikroskopii elektronowej i
analizą struktury chemicznej za pomocą spektroskopii
fotoelektronów. Pomiary przeprowadzano w szerokim zakresie
temperatur i w ściśle kontrolowanej atmosferze. Umożliwiło to
zaobserwowanie zmian zachodzących w zachowaniu nośników ładunku w
układach grafenowych w zależności od parametrów strukturalnych i
fizykochemicznych oraz pod wpływem adsorpcji różnego rodzaju
molekuł i zewnętrznego pola elektrycznego. Przedstawione wyniki
pozwalają na wskazanie możliwości kontroli zachowania nośników
ładunku w badanych materiałach, pod kątem zwiększenia ich
przydatności w różnych zastosowaniach.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/399/
Date: Tuesday 2018.09.26
Speaker: Dr. Ievgen I. Arkhipov
Affiliation: Joint Laboratory of Optics of Palacky University and
Institute of Physics of CAS, Olomouc, Czech Republic
Title: Complete characterization of nonclassicality of Gaussian
states of light by means of intensity moments
Abstract: Nonclassicality of light plays a crucial role in the
field of quantum optics. The discovery of the nonclassical
properties of light has led to the establishment of new branches
of quantum physics, e.g., quantum information theory. One of the
most known form of the nonclassicality of light is the
entanglement, where different modes of quantum fields exhibit
quantum correlations which have no analogue in the classical
optics. Though a lot of progress has been made in the theory of
the nonclassicality of the Gaussian states, still, the problem,
how one can directly certify the nonclassicality of the Gaussian
states in the experiment with the least available sources, has not
been solved yet. During the seminar, I will present a new
experimental method for complete identification of nonclassicality
of Gaussian states of light in the whole phase space. The proposed
method relies on nonclassicality witnesses written in terms of
measured integrated intensity moments up to the second order,
provided that appropriate local coherent displacements are applied
to the state under consideration.
Chair: Prof. Adam Miranowicz
Seminar language: English
/398/
Data: środa 2018.09.19, godz. 13:00
Prelegent: Dr. hab. Marcin Ziółek
Afiliacja: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
Tytuł: Korelacje parametrów fotoogniw z wynikami
czasowo-rozdzielczych badań laserowych (Seminarium profesorskie)
Streszczenie: Impulsowa spektroskopia laserowa pracująca w zakresie
femtosekund, pikosekund i nanosekund staje się ważnym i coraz
bardziej popularnym narzędziem badań podstawowych, umożliwiającym
obserwacje najszybszych procesów zachodzących w przyrodzie. Za
pomocą takiej spektroskopii możemy także poznać mechanizmy i
dynamikę procesów transportu ładunków w fotoogniwach. Czy jednak
badania z użyciem femtosekundowych impulsów laserowych mogą dzięki
temu zostać użyte do bardziej praktycznych celów i pomóc w
uzyskiwaniu lepszej sprawności ogniw słonecznych? Od kilku lat
rozwijamy w naszej grupie badawczej czasowo-rozdzielcze
absorpcyjne i emisyjne techniki laserowe stosowane do pomiarów
fotoogniw barwnikowych (dye-sensitized solar cells) oraz fotoogniw
perowskitowych. Specjalizujemy się w badaniu gotowych ogniw, które
konstruujemy i dla których wykonujemy podstawowe pomiary
fotowoltaiczne. Takie funkcjonale próbki są przedmiotem
spektroskopowych badań laserowych, których głównym celem jest
zaobserwowanie korelacji między zmierzonymi parametrami ogniw
słonecznych a wynikami badań w krótkich czasach.
Prowadzący: Dr. hab. Krzysztof Gibasiewicz
Seminar language: English
/397/
Date: Wednesday 2018.09.5
Speaker: Dr. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Nonlinear temporal and spatial properties of quantum
states: sequential and interferometric measurement methods in
optics (Seminarium habilitacyjne)
Abstract: Quantum information processing is an interdisciplinary
field of research where physics meets information science and
engineering. Its potential applications range from securing
communications to solving computational tasks that have been
infeasible on computers that relied on classical physics. These
applications exploit the quantum features of a given quantum state
through specifically designed hardware, e.g., quantum
entanglement, fidelity, and temporal steering. Full quantum
tomography is frequently conducted to characterise some of these
features, which becomes prohibitively time consuming, especially
in large systems. In this talk, I discuss alternatives to
characterising quantum systems based on sequential and
interferometric methods as well as experimental challenges related
to their implementation.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/396/
Date: Wednesday 2018.08.8
Speaker: Doc. Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Multiphoton experiments in Olomouc
Abstract: The talk will present the current state of the
multiphoton quantum laboratory in Olomouc. I shall summarize
recent experiments with three and four photons as quantum
information carriers. Specifically, I will discuss our experiments
on collective entanglement witnesses, quantum router and
controlled quantum teleportation.
Chair: Dr. Karol Bartkiewicz
Seminar language: English
/395/
Date: Monday 2018.07.23
Speaker: M.Sc. Jessica Taylor Flach
Affiliation: Department of Chemistry, University of
Wisconsin–Madison, USA
Title: Two-dimensional white-light spectroscopy and its
applications for understanding carbon nanotube and perovskite
photophysics
Abstract: This talk will give a general overview of the techniques
involved in using two-dimensional electronic spectroscopy (2D-ES)
and illustrate how 2D-ES can be used to study energy and charge
transfer processes in materials of interest for next generation
photovoltaics. The first part of this talk will focus on
understanding the photophysics of carbon nanotube thin films and
devices. Using our two-dimensional white-light (2D-WL)
spectrometer we are able to explore exciton diffusion and hopping
dynamics in order to better inform carbon nanotube device design.
In the second part of this talk I will discuss our newer, faster
version of 2D-WL spectroscopy using a pulse shaper and present an
initial report on perovskite photophysics.
Chair: Prof. UAM Marcin Ziółek
Seminar language: English
/394/
Date: Wednesday 2018.07.11
Speaker: Dr. Jorge Augusto Otálora Arias
Affiliation: Institute for Metallic Materials Leibniz Institute
for Solid State and Material Research, Dresden, Germany
Title: Towards a three dimensional curvilinear magnonic device
Abstract: The research field called Magnonics emerged with the
paradigm of harnessing spin-waves (SWs) as the elemental carrier
of information. With up to terahertz (THz) oscillation frequencies
with nanometric wavelengths and over macroscopic propagation
distances without electron charges being displaced, harnessing
magnons paves the way toward applications with minimum joule
heating effect, therefore with unprecedentedly low power
consumption (energy- friendly environmental devices),
reconfigurable functionality, faster operation and further
miniaturization. The wavelike properties of SWs as phase and
amplitude provides additional degrees of freedom in data
processing and sensing, which lead for instance, to novel
prototype building blocks of SW-based logic [1] and smart device
for very efficient SW propagation channels [2]. The kernel of such
applications generally consists of the so-called magnonic
waveguides (MGs) and magnonic crystals (MCs), which are
meta-materials characterized by their unprecedented on-demand
reprogrammable functionality. Whether MGs or MCs, three aspects
are generally assessed at the moment of studying SWs properties
for fundamental physics and magnonic applications: (i) High
efficiency in transmitting SWs power along magnetic tracks with
minimum energy consumption, sub-micrometer wave length encoding (<
1 µm), large group velocity limits ( > 1000 m/s), large decay
length ( > 6 µm) and small frequency linewidth ( < 100 MHz); (ii)
large and tunable nonreciprocities in the dispersion relation,
amplitude, power absorption, frequency linewidth and decay length
of SWs, at sub-micrometer wavelengths, above GHz frequency range,
and minimized energy expenditure. This feature is particularly
advantageous in analog and digital operation based in SW logic
devices, since non-reciprocity provides the condition for the
unidirectional propagation of SW packages (avoiding the formation
of standing SWs), which is strategic for enhancing the
input/output information transfer encoded in the phase, frequency
and amplitude of SWs; and (iii) efficient interface for
input/output signals conversion between magnons and other types of
information carries at high resolution of SW phase and frequency,
and over a broad range of frequency coverage. Accordingly, it can
be suggested that the ideal magnonic layout is that one which
allows the versatility of enclosing the aforementioned three
aspects in one single device; hence the potential of SWs as
information carriers can be fully exploited. According to
literature, these three aspects have been mainly studied in planar
two-dimensional (2D) thin films, nevertheless, there is not yet a
clear example wherein all of them can be achieved in only one
single magnonic layout at once. We think that a promising route
would consist in curving the 2D template into a curvilinear
3D-dimesional geometry, which simultaneously bring novelty to
Magnonics because the intrinsic curvature-induced magneto-chiral
effects in SWs.[3-5] This talk will be addressed in this
direction.
[1] Wang et al., Sci. Adv. 4, e1701517 (2018)
[2] Wagner et al., Nat. Nanotech. (2016)
[3] Otálora et al., Phys. Rev. Lett. 117, 227203 (2016)
[4] Otálora et al., Phys. Rev. B. 95, 184415 (2017)
[5] Otálora et al., Phys. Rev. B. 98, 014403 (2018)
Chair: Prof. Maciej Krawczyk
Seminar language: English
/393/
Date: Tuesday 2018.07.10
Speaker: M.Sc. Edgar Aguilar
Affiliation: National Quantum Information Centre, University of
Gdańsk, Sopot, Poland
Title: Certifying an Irreducible 1024-Dimensional Photonic State
Using Refined Dimension Witnesses
Abstract: We report on a new class of dimension witnesses, based
on quantum random access codes, which are a function of the
recorded statistics and that have different bounds for all
possible decompositions of a high-dimensional physical system.
Thus, it certifies the dimension of the system and has the new
distinct feature of identifying whether the high-dimensional
system is decomposable in terms of lower dimensional subsystems.
To demonstrate the practicability of this technique, we used it to
experimentally certify the generation of an irreducible
1024-dimensional photonic quantum state. Therefore, certifying
that the state is not multipartite or encoded using noncoupled
different degrees of freedom of a single photon. Our protocol
should find applications in a broad class of modern quantum
information experiments addressing the generation of
high-dimensional quantum systems, where quantum tomography may
become intractable [1].
[1] Edgar A. Aguilar, Máté Farkas, Daniel Martínez, Matías
Alvarado, Jaime Carine, Guilherme B. Xavier, Johanna F. Barra,
Gustavo Canas, Marcin Pawłowski, and Gustavo Lima, Phys. Rev.
Lett. 120, 230503 (2018).
Chair: Dr. hab. Paweł Kurzyński
Seminar language: English
/392/
Data: piątek 2018.07.6
Prelegent: Dr. hab. Jolanta Natalia Latosińska
Afiliacja: Wydział Fizyki UAM
Tytuł: „Całość to znacznie więcej niż suma części” – niezależnie
od skali (Seminarium profesorskie)
Streszczenie: Synergia (z gr. “συν” oznaczające
“razem”, oraz “ϵργια” – dzieło,
działanie) w kontekście badań naukowych oznacza podejście
całościowe – kompleksowe. Od początku kariery naukowej
zdecydowałam się na interdyscyplinarny charakter swoich badań i
podążałam w tym kierunku konsekwentnie, pomimo wielu przeciwności.
Obecnie badania interdyscyplinarne stanowią swego rodzaju
standard, ale w latach 90-tych takie podejście łączenia ze sobą
różnych dziedzin było nawet nie do pomyślenia. Jednakże ja
upatrywałam w nim nie tylko szanse na poszerzanie perspektyw
badawczych, ale i kryjący się za tym ogromny potencjał. Z upływem
czasu tematyka moich interdyscyplinarnych prac naukowych stopniowo
ewoluowała w kierunku poszerzonej interdyscyplinarności
(multidyscyplinarności), łącząc fizykę, chemię, informatykę,
farmację, biofizykę, a w ostatnich latach również matematykę,
meteorologię, klimatologię, astronomię oraz ochronę środowiska.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/391/
Date: Wednesday 2018.07.4
Speaker: Dr. Zbigniew Rozynek
Affiliation: Institute of Acoustics, Faculty of Physics, UAM
Title: Particle assembly and droplet manipulation by electric
fields (Seminarium habilitacyjne)
Abstract: Droplets covered by micro- and nanoparticles have
recently received considerable research interest, as they are
promising for various practical applications, such as in food
technology, the oil industry, biofuel processing, and improving
pharmaceutical products. Moreover, such droplets possess
characteristics that make them useful as experimental model
systems for studying, for example, particle effects on interfacial
tension, particle crystal growth and ordering or particle-layer
buckling on curved interfaces, particle assembly and rearrangement
on droplets’ surfaces, and particle detachment from droplets.
Particle-covered droplets can additionally be employed for
fabricating porous structures, granular or colloidal capsules of
different mechanical properties, morphologies, or shapes, and
adaptive structures. In this context, broadening one’s knowledge
of particle-covered droplet stability, deformation, and
surface-particle manipulation is essential to further developing
the above-mentioned research areas. The deformation of droplets
can be induced and investigated using various experimental tools,
including atomic force microscopes, microfluidic devices, or
mechanical shearing. For manipulating the surface or bulk
particles, many physical or chemical approaches exist, such as
pH-controlled particle assembly, acoustic wave–induced bulk and
surface particle convection, magnetic field–directed particle
assembly, and electric field–assisted particle arrangements. In
this seminar I will demonstrate how we utilized various electric
field phenomena to study the behaviour of particle-covered
droplets subjected to electric fields, including steady-state
deformation and transient deformation of such droplets, as well as
the mechanics and rheological properties of particle shells formed
on droplets. I will also show that electric fields can be used for
manipulating particles in the bulk and at the surface of the
droplet by exerting forces that were acting on them either
directly, e.g. through particle motion via dipolar forces, or
indirectly, e.g. by particle convection through electric
field–induced liquid flows.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/390/
Date: Tuesday 2018.07.03
Speaker: Prof. Richard J. Spontak
Affiliation: Departments of Chemical & Biomolecular Engineering
and Materials Science & Engineering, North Carolina State
University, Raleigh NC 27695
Title: Photodynamic Polymers as Comprehensive Anti-Infective
Materials: Staying Ahead of a Growing Global Threat
Abstract: Adherence of pathogens such as bacteria and viruses on
various surfaces routinely leads to subsequent transmission to new
hosts, significantly promoting the proliferation of potentially
harmful organisms. This sequence is particularly worrisome in the
case of antibiotic-resistant pathogens, which are becoming a
global threat to human health. According to the Centers for
Disease Control and Prevention, 1 out of every 20 hospital
patients is affected by nosocomial infections, subsequently
resulting in 100,000 deaths annually in the United States alone.
Out of these, about 23,000 deaths are attributed to drug-resistant
pathogens such as methicillin-resistant Staphylococcus aureus (S.
aureus) or vancomycin-resistant Enterococcus faecium (E. faecium).
Strains referred to as "nightmare bacteria" with highly elevated
resistance to last-resort antibiotics have been reported all
around the world in 2017. While silver, copper, zinc oxide or
titanium dioxide have been used as surfaces or introduced as
nanoparticles into a broad range of substrates to serve as
antimicrobial agents and eradicate a wide range of pathogens, they
all suffer from eventual reservoir depletion, and they tend to be
pathogen- or condition-specific. Moreover, if not covalently bound
or tightly embedded, these nanoparticles can leach into the
environment and introduce additional health concerns. In this
study, we discuss a photodynamic polymer composed of an olefinic
thermoplastic elastomer modified with zinc
tetra(4-N-methylpyridyl)porphine (ZnTMPyP4+), a photoactive
antimicrobial, and demonstrate that this combination is remarkably
effective at inactivating 5 bacterial strains, including S. aureus
and Escheria coli (E. coli) often associated with food poisoning,
and 2 different viruses, including Human adenovirus-5, upon
exposure to non-coherent light at an intensity of 65-80 mW/cm2
for 60 min. By achieving antibacterial and antiviral efficacies of
at least 99.89% and 99.95%, respectively, this methodology based
on the light-induced creation of singlet oxygen constitutes a
non-specific and highly successful route by which to eliminate
harmful pathogens by simple exposure to visible light and oxygen.
Chair: Prof. Michał Banaszak
Seminar language: English
/389/
Date: Wednesday 2018.06.27
Speaker: Dr-Ing. Wolfgang Jaschinski
Affiliation: Leibniz Research Centre for Working Environment and
Human Factors, Technische Universität Dortmund
Title: Physical dimensions follow physiological functions:
Ergonomics at the computer workstation.
Abstract: Using computers means work for muscular systems, e.g.
the intra-ocular muscle of the focussing system in the eyes, the
extra-ocular muscles for moving the eyes, the muscles of the neck
and the back. These physiological systems have properties that
have developed during evolution in natural environments. For
comfortable computer work, these individual physiological
functions should be considered when arranging and designing the
computer workstation for the individual user. Optometry provides
appropriate eye glasses for clear vision.
[1] Jaschinski W (2017) Individual Objective and Subjective Fixation Disparity in Near Vision. PLoS ONE 12(1).
[2] Schroth, V.; Joos, R.; Jaschinski, W.: Effects of prism eyeglasses on objective and subjective fixation disparity. PLoS ONE 10: e0138871 (29 pp.) (2015)
[3] Weidling P, Jaschinski W: The vertical monitor position for presbyopic computer users with progressive lenses: how to reach clear vision and comfortable head posture. Ergonomics 58: 1819-1829 (2015)
[4] Jaschinski W, König M, Mekontso TM, Ohlendorf A, Welscher M: Comparison of progressive addition lenses for general purpose and for computer vision: an office field study. Clin Exp Optom 98: 234-243 (2015)
[5] König M, Haensel C, Jaschinski W: How to place the computer monitor: measurements of vertical zones of clear vision with presbyopic corrections. Clin Exp Optom 98: 244-253 (2015)
Chair: Dr. Alicja Brenk-Krakowska
Seminar language: English
/388/
Date: Friday 2018.06.22
Speaker: Dr. Ravindra Chhajlany
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Field-controlled quantum matter: exploration of long-range
order in reduced dimensions (Kwantowa materia kontrolowana
światłem: dalekozasięgowe uporządkowania w zredukowanych
wymiarach) - Seminarium habilitacyjne
Abstract: The forms of so-called “quantum matter” - where quantum
effects are crucially manifested at the macroscopic scale - range
from phases of “traditional” strongly correlated many body systems
to exotic topological systems. Research on two parallel wide
classes of systems are providing access and understanding to
various aspects of many body physics - (i) so called quantum
simulators of matter (“idealized materials”), and of course (ii)
various real materials, controlled in novel ways. In particular,
quantum simulators in controlled environments based on platforms
of ultracold particles trapped in optical lattices, ion traps,
nano-photonic systems can be engineered to access often extreme
parameter regimes rarely accessible before in real materials,
using control via light or magnetic fields. Similarly, advances in
ultra-fast spectroscopy are facilitating the manipulation of real
materials at a microscopic level using light instead of the more
traditional control of pressure, temperature etc. These new ways
of controlling and manipulating matter pose theoretical
challenges. In this seminar, I will summarize some results of
research that I have been part of in this exciting field that will
constitute my Habilitation dissertation - all of which concern the
description of properties and control of long range ordered phases
in d=1 or 2 dimensional systems. In particular, I will talk about:
(i) engineering extreme correlated hopping for ultra-cold atoms
and associated physical properties (ii) non-trivial gauge field
effects in an exemplary one-dimensional system (iii) effects of
gauge fields in a spinor boson gas (iv) proximity effects in an
engineered bilayer system and (v) control of orbital order in a
paradigmatic manganite.
Chair: Prof. Adam Miranowicz
Seminar language: English
/387/
Data: środa 2018.06.20
Prelegent: Dr n. med. Krzysztof Michalak
Afiliacja: Pracownia Fizyki Widzenia i Optometrii, Wydział Fizyki
UAM
Tytuł: Wyznaczanie złożoności wysokowymiarowych sygnałów
nieliniowych (Seminarium habilitacyjne)
Streszczenie: Sygnały chaotyczne to sygnały opisane przez
deterministyczne układy równań różniczkowych, których rozwiązaniem
jest nieregularny przebieg zmiennych w czasie.
Jedną z miar ukrytej, częściowej regularności jest Wymiar
Korelacyjny (d, Correlation Dimension).
Dostępne w literaturze algorytmy wyznaczania tego parametru dają
jednak błędne wyniki w przypadku sygnałów wysoko wymiarowych,
czyli o złożoności przekraczającej d=5.
Prezentacja przedstawia wyniki wielu symulacji numerycznych i
analiz wyjaśniających przyczyny błędów estymacji dla sygnałów
wysoko wymiarowych oraz poprawne sposoby wyznaczania tego
parametru.
Analiza skupiona była zarówno na poprawieniu dokładności
wyznaczania d, oszacowaniu dokładności tej estymacji, jak i na
przyspieszeniu obliczeń, które w przypadku sygnałów wysoko
wymiarowych są bardzo czasochłonne.
Końcowym efektem pracy jest w dużej mierze nowy algorytm, który
wyznacza d z dużą dokładnością w znacznie krótszym czasie i który
zaimplementowany jest w zestawie funkcji Matlab udostępnionych do
swobodnego wykorzystania.
Metoda może mieć zastosowanie w wielu
dziedzinach nauki, w których mamy do czynienia z układami
chaotycznymi: w fizyce, chemii, biologii, ekonomii, meteorologii
itp.
Prowadzący: Prof. Adam Miranowicz
Seminar language: Polish
/386/
Date: Thursday 2018.06.14
Speaker: Prof. Jan Peřina Jr.
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Science of the Czech
Republic, Olomouc, Czech Republic
Title: Sub-Poissonian light
Abstract: Different definitions of higher-order
sub-Poissonian-like fields based on the moments of integrated
intensity, photon number, integrated-intensity fluctuation,
photon-number fluctuation and using the elements of photocount
(photon-number) distributions will be introduced. Their mutual
relations will be elucidated. Using the set of potentially
sub-Poissonian fields obtained by post-selection from a twin beam
based on photon-number-resolving detection their power to
experimentally indicate non-classicality will be discussed. The
generation of sub-Poissonian-like optical fields up to the
fifth-order in intensity moments and up to the eleventh-order in
the elements of photocount distribution will be mentioned.
Chair: Prof. Adam Miranowicz
/385/
Date: Monday 2018.06.11
Speaker: Dr. Andrii Sotnikov
Affiliation: Institute of Solid State Physics, TU Wien, Vienna,
Austria
Title: Aspects of the Hubbard model and challenges for quantum
computers
Abstract: After 55 years since its formulation, the Hubbard model
keeps many problems open till present days. We discuss main
reasons for the difficulty to access particular regimes of this
simple model even with modern computational possibilities. It will
be shown that the Hubbard model is universal in the sense that it
can describe large classes of materials and strongly-correlated
many-body phases of interest, in particular, high-temperature
superconductors and excitonic insulators. For these two cases,
several recent experimental achievements and current level of
theoretical description will be pointed out. With all problems in
mind, a natural question arises: “Can universal quantum simulators
or quantum computers help to gain further physical insights in the
Hubbard model?” According to recent progress in these fields, we
tend to answer “yes”, but there are still many challenges on the
way.
Chair: Dr. Agnieszka Cichy
Seminar language: English
/384/
Date: Wednesday 2018.05.30
Speaker: Dr. Piotr Biskupski
Affiliation: IBM Systems - File |
Object Storage - Technical
Leader, CEE, IBM Q Ambassador
Title: The future is quantum - IBM Q experience
Abstract: The rate of progress has been remarkable. Only a year
and a half ago, we put the IBM Q experience prototype 5-qubit
machine in the cloud, and made it available for the world to use,
explore, and learn from. A year later, we added a second device
with 16 qubits. Today, more than 60,000 users from more than 1,500
universities, 300 high schools, and 300 private institutions have
registered for accounts on the IBM Q experience, and collectively
run 1.7 million experiments. The members of the research community
have also published more than 35 research papers using our
platform as a testbed for ideas. This is only the beginning.
Chair: Prof. Adam Miranowicz
Seminar language: English
/383/
Data: poniedziałek 2018.05.28
Prelegent: Dr Marta Targosz-Korecka
Afiliacja: Zakład Fizyki Nanostruktur i Nanotechnologii, Wydział
Fizyki, Astronomii i Informatyki Stosowanej, Uniwersytet
Jagielloński
Tytuł: Właściwości mechaniczne komórek w rozwoju oraz przebiegu
chorób cywilizacyjnych - obraz na podstawie badań z wykorzystaniem
mikroskopu sił atomowych (Seminarium habilitacyjne)
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/382/
Date: Monday 2018.05.21
Speaker: Ph.D. Eng. Przemysław Głowacki
Affiliation: Physikalisch-Technische Bundesanstalt, Braunschweig,
Germany and Poznań University of Technology, Poznań, Poland
Title: Laser spectroscopic characterization of the nuclear-clock
isomer 229mTh
Abstract: [PDF]
Chair: Prof. Maciej Krawczyk
Seminar language: English
/381/
Data: środa 2018.05.16
Prelegent: Dr Piotr Kozłowski
Afiliacja: Zakład Fizyki Komputerowej, Wydział Fizyki UAM
Tytuł: Wyjaśnienie własności magnetycznych i elektronowych
wybranych nanomagnetyków molekularnych na bazie jonów chromu i
wanadu (Seminarium habilitacyjne)
Streszczenie: [PDF]
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/380/
Data: piątek 2018.05.11
Prelegent: Dr Wojciech Dimitrow
Afiliacja: Instytut Obserwatorium Astronomiczne, Wydział Fizyki
UAM
Tytuł: Układy wielokrotne gwiazd - powstawanie, obserwacje oraz
modelowanie (Seminarium habilitacyjne)
Streszczenie: Podczas prezentacji zostaną przedstawione wyniki
obserwacji oraz modelowania układów wielokrotnych gwiazd
zawierających parę zaćmieniową. W ramach wprowadzenia zostanie
omówiony proces powstawania gwiazd w obłokach molekularnych.
Przedstawione będą różne typy obiektów oraz interesujące wyniki
obserwacyjne z ostatnich lat. Dynamika i stabilność takich układów
oraz możliwość obecności planet jest kolejnym ważnym problemem.
Tematyka powstawania gwiazd jest ściśle związana z badaniami
układów wielokrotnych. Obserwacje dostarczają informacji które
pozwalają zweryfikować współczesne teorie formowania się gwiazd.
Przedstawione będą instrumenty badawcze dzięki którym zgromadzono
dane spektroskopowe i fotometryczne niezbędne do modelowania
pięciu wybranych układów wielokrotnych. Omówione zostaną
podstawowe zastosowane metody - pomiarów prędkości radialnych
(efekt Dopplera) oraz modelowania par zaćmieniowych. Dla pięciu
badanych układów udało się odkryć nowe składniki spektroskopowe,
wyjaśnić hierarchie układów oraz otrzymać parametry orbitalne,
takie jak okresy, rozmiary, mimośrody oraz nachylenia. Ponadto
wyznaczono masy, promienie, temperatury, kształt oraz skład
chemiczny składników par zaćmieniowych. Na podstawie tych wyników
można określić status ewolucyjny badanego obiektu oraz wyznaczyć
jego odległość.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/379/
Data: środa 2018.05.09
Prelegent: Prof. Jan Barciszewski
Afiliacja: Instytut Chemii Bioorganicznej Polskiej Akademii Nauk i
Centrum Nanobiomedyczne UAM, Poznań
Tytuł: Genetyka to za mało
Streszczenie: Nauki biologiczne można podzielić na biochemię,
genetykę, biologię molekularną i epigenetykę. Generalnie biologia
molekularna analizuje znane produkty znanych genów, biochemia
zajmuje się badaniami znanych produktów nieznanych genów a
zadaniem genetyki jest analiza znanych genów nieznanych produktów.
Poznańie sekwencji nukleotydowej ludzkiego genomu w 2003 roku było
jednym z największych osiągnięć genetyki. Genom człowieka składa
się z ponad 3 miliardów par zasad i zawiera ok. 21000 genów
kodujących białka, co stanowi zaledwie 2% genomu. Liczba genów
człowieka jest tylko o około 50 większa od liczby genów szympansa,
natomiast bakteria Escherichia coli ma 4300 genów, drożdże piwne -
6300 genów, rzodkiewnik pospolity – 25000, a ryż – 50000. Dwoje
niespokrewnionych ludzi wykazuje identyczność 99,9% sekwencji
nukleotydowej DNA. W całej populacji ludzkiej różnice dotyczą
tylko 0,3% sekwencji genomu. Pozostałe 98% genomu, choć nie
koduje białek (są tam m.in. mobilne elementy genetyczne,
pseudogeny czy introny) jest tak samo ważna dla funkcjonowania
komórki. Część pseudogenów pozostaje transkrypcyjnie nieaktywna,
ale z większości powstają RNA, które nie są przepisywane na
białko, ale mogą regulować ekspresję genów. Każda komórka naszego
organizmu zawiera ten sam genom (DNA), ale mimo tego komórki
bardzo się od siebie różnią. W komórce istnieją mechanizmy
powodujące zmiany epigenetyczne (epi: poza, ponad), które wpływają
na ekspresję genów ale nie zmieniają sekwencji DNA. Jednym z
mechanizmów epigenetycznych jest metylacja DNA, a drugi
modyfikacja (metylacja, acetylacja) histonów. Modyfikacje
epigenetyczne, są często efektem reakcji organizmu na zmieniające
się warunki otoczenia oraz decydują o jego możliwościach
adaptacyjnych. Poszukiwania epigenetyczne polegają na
identyfikacji elementów chemicznych, które modyfikują genom,
zarządzają komórkami, i zmieniają długoterminową ekspresję genów.
Okazało się, że nie tylko substancje chemiczne ale również
uwarunkowania społeczne mogą wpływać na jej zakres. Modyfikacje
epigenetyczne mogą się pojawić w wieku dorosłym, młodzieńczym, a
nawet in utero. W konsekwencji, określone wydarzenie z dzieciństwa
może zmienić sposób, w jaki geny reagują w innej sytuacji w wieku
dorosłym. Przechodząc na grunt medycyny, zauważono, że w procesie
nowotworzenia następuje obniżenie globalnego poziomu metylacji DNA
oraz podwyższenie metylacji promotorów genów supresorowych a także
modyfikacje histonów, co prowadzi do zmian w ekspresji genów.
Bazując na tych obserwacjach, podejmowane są próby terapeutycznego
wykorzystania mechanizmów epigenetycznych ograniczając negatywny
wpływ demetylacji DNA czy acetylacji histonów.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/378/
Data: środa 2018.04.25
Prelegent: Prof. Halina Abramczyk
Afiliacja: Institute of Applied Radiation Chemistry, Łódź
University of Technology
Tytuł: Obrazowanie ramanowskie, AFM i SNOM w onkologii.
Prowadząca: Dr Małgorzata Paprzycka
Seminar language: Polish
/377/
Date: Tuesday 2018.04.24
Speaker: Dr Peter Alexander Bouvrie
Affiliation: Centro Brasileiro de Pesquisas Físicas
Title: Quantum information with ultracold interacting Fermi gases
Abstract: Multiparticle entangled states, essential ingredients
for modern quantum technologies, are routinely generated in
experiments of atomic Bose-Einstein condensates (BECs). However,
entanglement in ultracold interacting Fermi gases has not been
exploited yet. Here, using a theory of composite bosons we show
that many-particle entanglement between two fermionic ensembles
localized in spatially separated modes can be generated by
splitting an ultracold interacting Fermi gas in the (molecular)
BEC regime. This entanglement relies on the fundamental fermion
exchange symmetry of molecular constituents and might be used for
implementing quantum information tasks such as Bell test of
quantum nonlocality. We also predict that large ensembles, of the
order of 105 fully entangled fermionic atoms, could be
generated in current experiments of ultracold interacting Fermi
gases.
Chair: Dr hab. Paweł Kurzyński
Seminar language: English
/376/
Data: środa 2018.04.18
Prelegent: Dr Wojciech Grudziński
Afiliacja: Zakład Biofizyki, Instytut Fizyki, Wydział Matematyki,
Fizyki i Informatyki, Uniwersytet Marii Curie-Skłodowskiej w
Lublinie
Tytuł: Synergistyczny efekt zastosowania spektroskopii
fluorescencyjnej i ramanowskiej polienów w badaniach oraz
obrazowaniu struktur biologicznych (Seminarium habilitacyjne)
Streszczenie: Polieny, włączając karotenoidy oraz antybiotyk
amfoterycyna B, odgrywają różne, niezwykle ważne role biologiczne.
W układach naturalnych ich funkcjonowanie opiera się głównie na
modyfikacji fizycznych właściwości błon oraz protekcyjnym
działaniu antyoksydacyjnym. Organizacja tych cząsteczek w błonach
lipidowych związana jest ściśle z mechanizmami molekularnymi
odpowiedzialnymi za funkcje jakie odgrywają one w organizmach
żywych.
Komplementarne zastosowanie spektroskopii Ramana i spektroskopii
fluorescencyjnej w badaniach polienów pozwala na unikalną analizę
oraz obrazowanie struktur biologicznych w mikroskali. Podejście
opierające się na równoczesnym użyciu dwu technik mikroskopowych
wykorzystane zostało, między innymi, do badań organizacji
molekularnej, lokalizacji oraz orientacji karotenoidów, a także
antybiotyku polienowego.
Podczas wystąpienia zaprezentowane zostaną wyniki badań oraz
analizy przeprowadzone dla polienów (luteiny, zeaksantyny,
amfoterycyny B) wbudowywanych do modelowych błon lipidowych w
postaci bardzo dużych, jednowarstwowych struktur liposomowych (GUV
ang. Giant Unilamellar Vesicles) formowanych z lecytyny. Dane
uzyskane z pomiarów fluorescencyjnych umożliwiły określenie
lokalizacji cząsteczek, a także dały podstawę do stwierdzenia jaką
formę organizacji molekularnej przyjmują analizowane związki.
Szczegółowa analiza z wykorzystaniem oryginalnej metody pozwoliła
precyzyjnie wyznaczyć orientację polienów względem osi normalnej
do błony lipidowej. Spektroskopia ramanowska, poza lokalizacją
polienów w strukturach lipidowych, umożliwiła uzyskanie informacji
o formach stereoizomerycznych karotenoidów występujących w
badanych układach, a także o ich rozmieszczeniu w obrębie
analizowanego systemu.
Przedstawione badania pozwalają, między innymi zrozumieć rolę jaką
odgrywają luteina i zeaksantyna w plamce żółtej oka ludzkiego oraz
jakie jest ich znaczenie w procesie nieodwracalnej utraty wzroku w
wyniku starczego zwyrodnienia siatkówki (AMD, ang. Age-related
Macular Degeneration). Dzięki uzyskanym wynikom zweryfikowano
hipotezy dotyczące funkcji ochronnych pełnionych przez karotenoidy
na poziomie molekularnym. Przeprowadzone badania antybiotyku
polienowego amfoterycyny B pozwoliły zidentyfikować molekularne
determinanty toksyczności tego leku dla pacjentów.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/375/
Date: Wednesday 2018.04.11 at 13:00
Speaker: Dr Michał Karpiński
Affiliation: Quantum Photonics Laboratory, University of Warsaw
Title: Spectral shaping of single-photon pulses
Abstract: The spectral-temporal degree of freedom of light has
recently been recognized as a promising platform for encoding and
transmission of quantum information. This requires the ability to
modify the spectral and temporal profiles of single-photon light
pulses. During the seminar I will talk about the methods of
spectral modification of quantum light using electro-optic phase
modulation. This method allows to change the time-spectral profile
of the light pulse in a deterministic and, in principle, unitary
way, i.e. without the use of filtering or amplification. In
particular, I will present experimental results on efficient
modification of the spectral bandwidth of single-photon pulses of
light and discuss their significance in the context of the
development of quantum networks.
Chair: Prof. Adam Miranowicz
Seminar language: English
/374/
Data: środa 2018.03.28
Prelegent: Dr Beata Łuszczyńska
Afiliacja: Katedra Fizyki Molekularnej, Wydział Chemiczny,
Politechnika Łódzka
Tytuł: Podstawy fizyczne procesu optymalizacji organicznych i
hybrydowych fotodiod pracujących w zakresie bliskiej podczerwieni
(Seminarium habilitacyjne)
Streszczenie: Organiczne urządzenia optoelektroniczne - diody
elektroluminescencyjne, ogniwa fotowoltaiczne oraz fotodiody -
wykazują szereg niezwykłych właściwości, takich jak elastyczność,
lekka waga czy też możliwość wytwarzania elementów o dużej
powierzchni tanimi metodami drukarskimi, które są nieosiągalne dla
elektroniki nieorganicznej. Mimo to, drukowana elektronika
organiczna nie znalazła jeszcze szerokiego zastosowania, gdyż
parametry pracy tak wytworzonych urządzeń nie spełniają wymagań
użytkowników. Seminarium będzie poświęcone metodzie optymalizacji
struktury organicznych i hybrydowych fotodetektorów, w celu
uzyskania urządzeń wykazujących dobre cechy użytkowe. Metoda ta
jest oparta na analizie zjawisk fizycznych wpływających na
parametry pracy fotodiod takich jak: generacja ekscytonów i ich
dysocjacja na swobodne nośniki ładunku, rekombinacja, pułapkowanie
i ruchliwość nośników ładunku, oraz przepływ prądów ograniczonych
ładunkiem przestrzennym. Taka analiza będzie przeprowadzona na
przykładzie dwóch klas urządzeń: fotodetektorów hybrydowych, w
których warstwę aktywną stanowiły układy organiczno-nieorganiczne
oparte na mieszaninie polimeru z nieorganicznymi nanocząstkami,
oraz fotodetektorów polimerowych wykorzystujących odpowiednio
zaprojektowane kopolimery donorowo-akceptorowe, które dzięki
wąskiej przerwie energetycznej są zdolne do absorpcji światła z
zakresu bliskiej podczerwieni. Proces optymalizacji obejmował
także dobór warstw blokujących niepożądany przepływ ładunku,
których zastosowanie umożliwia uzyskanie zbalansowanego transportu
elektronów i dziur oraz obniżenie prądów ciemnych co zwiększa
czułość fotodiod. Na seminarium zostaną zaprezentowane także
wstępne wyniki druku warstw aktywnych i opracowanych kompozycji
atramentów i omówione będą perspektywy rozwoju drukowanej
elektroniki organicznej.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/373/
Date: Friday 2018.03.23
Speaker: Dr Oleksandr Bondar
Affiliation: Sumy State University, Sumy, Ukraine
Title: Fabrication and Investigation of Multielement and
Multilayered Protective Coatings With Enhanced Physical-Mechanical
and Tribological Properties Based on Nitrides of Transition
Metals
Abstract: The presentation will be devoted to investigation of
structure, physical-mechanical and tribological properties of
multielement NbN, Nb-Si-N, Nb-Al-N, (Ti-Zr-Hf-V-Nb)N and
(Ti-Zr-Hf-V-Nb-Ta)N coatings, as well as multilayered TiN/MoN,
TiN/ZrN and MoN/CrN coatings with various bilayer thickness,
deposited using PVD methods (vacuum-arc evaporation of cathode or
reactive magnetron sputtering). Influence of deposition conditions
on microstructure and properties of the coatings will be
discussed. In addition, influence of high-temperature annealing
and high-dose ion implantation of Au- and N+ ions will also be
covered within the presentation.
Chair: Prof. UAM Krzysztof Grygiel
Seminar language: English
/372/
Data: środa 2018.03.21
Prelegent: Dr Danuta Stefańska
Afiliacja: Wydział Fizyki Technicznej, Politechnika Poznańska
Tytuł: Spektroskopowa analiza oddziaływań w atomach terbu i holmu
jako droga do zastosowań w kwantowej inżynierii i metrologii
Streszczenie: Tematyka wystąpienia obejmuje kompleksowe badania
struktury nadsubtelnej (w wybranych przypadkach również z
dodatkowym rozszczepieniem zeemanowskim) poziomów elektronowych
atomu i jonu terbu oraz atomu holmu, prowadzone metodą
fluorescencji wzbudzonej wiązką laserową, z użyciem jednomodowych
laserów przestrajalnych. Kluczowe w badaniach jest wykorzystanie
m.in. przestrajalnego lasera barwnikowego generującego w trudno
dostępnym zielonym zakresie spektralnym, pompowanego optycznie
laserem diodowym. Istotny postęp w analizie struktury elektronowej
dla wspomnianych pierwiastków, uzyskany w oparciu o wspomniane
badania eksperymentalne, może stanowić podstawę poszukiwania
zastosowań w kwantowej inżynierii i metrologii. Dla atomu holmu
zaproponowano schematy poziomów do pomiaru zmian czasowych stałej
struktury subtelnej. Rozważane są w dalszej perspektywie również
inne zastosowania dotyczące atomu terbu.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/371/
Date: Monday 2018.03.19
Speaker: Dr Wojciech Gawełda
Affiliation: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
Title: Time-resolved studies of chemical reaction dynamics using
ultrashort X-ray pulses (Seminarium habilitacyjne)
Abstract: Ultrafast structural dynamics is an emerging field
aiming to deliver a detailed understanding of the elementary steps
in reacting chemical species, which involve changes in their
nuclear, electronic and spin states. Such processes are vital
ingredients in chemistry and biology, but also in technological
applications, including efficient charge transport in light
harvesting molecules and ultrafast switchable molecular magnets.
In order to unravel this complex dynamic behavior we have
implemented a suite of ultrafast X-ray spectroscopic and
scattering tools to zoom into both the electronic and nuclear
structures, with the goal to ultimately deliver a molecular movie
of ongoing chemical processes. In view of the many potential
applications in chemical and biological dynamics it is desirable
to increase the sensitivity level of such experiments as well as
to decrease the time resolution into the femtosecond time domain.
In this talk I will present our benchmark results using a
versatile setup that permits simultaneous measurements of
ultrafast X-ray absorption and emission spectroscopies combined
with X-ray scattering, which has been recently implemented at
different synchrotrons and X-ray Free Electron Lasers. It has been
applied to study different photochemical reactions, ranging from
nascent radicals in solution, molecular spin transitions, and
ligand exchange reactions, to photocatalytic systems, with the
goal to deliver a deeper understanding of the elementary steps in
chemical reactivity.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/370/
Date: Wednesday 2018.03.14
Speaker: Dr hab. Tomasz Kwiatkowski
Affiliation: Astronomical Observatory, Faculty of Physics, Adam
Mickiewicz University in Poznań
Title: Where gravity no longer dominates: The internal structure
and evolution of the smallest asteroids
Abstract: Asteroids, space rocks orbiting the Sun, are very
diverse in composition. While the largest of them (500-1000 km)
are spheroidal bodies, and the middle-sized ones (0.1-500km) are
gravity-dominated, irregular rubble-piles, the smallest asteroids
(D < 0.1km) are either monolitic bodies or boulders held together
by the forces of cohesion. Observations suggest that many of the
smallest asteroids can be surprisingly weak bodies evolving under
the influence of the solar radiation. Since some of them come
close to the Earth, they can be easily observed or even visited by
space probes. This way they can serve as a laboratory for testing
physical phenomena controlling the evolution of the asteroids not
only in our Solar System, but also those orbiting around other
stars. The talk will be targeted for non-astronomers with the
emphasis on the physical phenomena in the low-gravity environment.
I will interpret images obtained from space probes, present shape
models used for testing theories and arrive at conclusions about
the internal structure and evolution of the smallest asteroids.
Chair: Prof. UAM Agnieszka Kryszczyńska
Seminar language: English
/369/
Date: Friday 2018.03.09
Speaker: Prof. Andrzej Dobek
Affiliation: Molecular Biophysics Division, Faculty of Physics,
Adam Mickiewicz University
Title: THz Kerr effect in water
Abstract: As a liquid, water plays a critical role in biological
systems. Its permanent dipole moment can interact favorably with
charged species. Water is an excellent hydrogen bonding solvent.
It has a balanced number of hydrogen bond donors and acceptors and
it has the smallest moment of inertia among small molecule polar
liquids. As such it demonstrates the fastest solvent relaxation
dynamics. In the liquid phase H2O molecules form a disordered
fluctuating network of intermolecular hydrogen bonds. The motions
of biomacromolecules depend on the structure and dynamics of
water. These motions take place over a many time-scales: from ns
(diffusion of H2O in the first solvation shell of protein),
through ps (amino-acid side motions) to sub-ps (librational and
phonon-like motion of H2O). The motions in a large range of
frequencies can be studied by the OKE, the anisotropic Raman
scattering and the dielectric techniques including THz-TDS. Using
these methods one can observe changes in the spectra of
biomacromolecules in water solution in the range 10 GHz-30 THz. In
the lecture the fundamentals of THz radiation, as well as optical
and THz Kerr effect will be reminded. THz–OKE measurements of
three water samples of deionized, distilled and buffered (PBS)
water will be reported and analyzed. These media were chosen in
order to study the effect of ions presence on water behavior in
the ultrafast time scale. The water most interesting from the
point of view of living cells studies is the one significantly
ionized. Therefore, discrimination between ultrafast effects
resulting from internal H2O properties from those resulting
from H2O – ions interactions are very important. These two
effects may be connected to difference in the fluctuations of the
network of intermolecular hydrogen bonds of water molecules in the
presence or absence of ions and cations in solution. These
fluctuations are expected to significantly alter water
birefringence amplitude and its dynamics.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/368/
Data: Środa 2018.03.07
Prelegent: Mgr Oleksadr Chumak
Afiliacja: Institute of Physics, Polish Academy of Science, Warsaw
Tytuł: Właściwości magnetosprężyste, anizotropia magnetyczna oraz
właściwości dysypatywne cienkich warstw stopów Heuslera.
Streszczenie: Na seminarium zostaną przedstawione badania cienkich
warstw stopów Heuslera Co2FexMn1−xSi (CFMS) i
Co2FeGa0.5Ge0.5 (CFGG). Wymienione wyżej stopy
charakteryzują się wysoką polaryzacją spinową i są dobrymi
kandydatami do zastosowań, między innymi w spintronice. W tych
materiałach ważną rolę odgrywają ich właściwości magnetosprężyste,
anizotropia magnetyczna oraz właściwości dysypatywne. Przede
wszystkim rozważany jest wpływ skończonej grubości warstwy
magnetycznej a także zastosowania różnych warstw buforowych oraz
powierzchniowych. Będą także przedstawione badania szeregu
dodatkowych parametrów charakteryzujących warstwy magnetyczne,
takich jak wartości całki wymiany, uporządkowanie chemiczne oraz
parametry tłumienia magnetycznego. Szczególnie zostanie
przedstawiona unikatowa technika Strain Modulated Ferromagnetic
Resonance (SMFMR), która umożliwia badania właściwości
magnetosprężystych cienkich warstw magnetycznych.
Przewodniczący: Prof. Maciej Krawczyk
Seminar language: Polish
/367/
Data: środa 2018.02.21
Prelegent: Dr Magdalena Widlicka
Afiliacja: Department of Optics & Photonics, Faculty of
Fundamental Problems of Technology, Wrocław University of Science
and Technology
Tytuł: Badania właściwości biomechanicznych gałki ocznej i ich
zastosowania w diagnostyce oka (Seminarium habilitacyjne)
Abstract: Tematyka seminarium obejmuje aspekty biomechaniki,
optyki i dynamiki gałki ocznej mające związek z powstawaniem
obrazu w układzie optycznym oka. Wykład przybliży cel naukowy
badań parametrów mechanicznych tkanek oka i ich skorelowania z
procesami fizjologicznymi i rozwojem patologii (w tym jaskry) w
oku. Oko człowieka jest strukturą, w której występuje ścisła
korelacja pomiędzy właściwościami mechanicznymi i refrakcyjnymi
oka. Oznacza to, że z powodów czysto optycznych parametry
strukturalne – geometryczne i materiałowe – muszą spełniać
określone warunki. Określenie tych warunków umożliwia
przewidywanie procesów fizjologicznych oraz diagnostycznych, w tym
skutków patologii oka. Część chorób oka ma etiologię mechaniczną,
do takich należy jaskra. Wiedza z zakresu mechaniki obejmuje
zarówno zjawiska fizjologiczne zachodzące wewnątrz gałki ocznej,
jak również efekty działań diagnostycznych. Jednym z takich
działań jest procedura pomiaru ciśnienia wewnątrzgałkowego
(tonometria). Wszystkie realistyczne modele gałki ocznej w
tonometrii i chirurgii refrakcyjnej muszą dzisiaj uwzględniać
zarówno zmienną grubość powłok oka, jak również nieliniowość ich
właściwości materiałowych. Prezentowane w literaturze modele
biomechaniczne oka, wykorzystywane w diagnostyce, stworzono
głównie pod kątem zastosowania albo w tonometrii albo w korekcji
refrakcji, natomiast nie uwzględniają one związku pomiędzy tymi
dwoma zastosowaniami. Ponadto istnieją też inne czynniki/procesy
fizjologiczne (np. puls oczny, akomodacja, zaćma, jaskra itp.),
które należy uwzględnić w modelowaniu i diagnostyce oka. Brakuje
dzisiaj kompaktowego modelu, zdolnego pełnić wszystkie powyższe
funkcje. Na seminarium zaprezentowane będą wyniki badań
zmierzające do określenia takiego modelu gałki ocznej.
Prowadzący: Prof. Michał Banaszak
Seminar language: Polish
/366/
Date: Wednesday 2018.02.14
Speaker: Dr Jan Guzowski
Affiliation: Instytut Chemii Fizycznej PAN, Warszawa
Title: Structure and dynamics of droplet aggregates: from small
clusters to elongated threads and large tissue-like conglomerates
Abstract: Generation and manipulation of tiny aqueous compartments
by external flow finds numerous applications in analytical
sciences where each compartment (droplet) may be used as a
separate chemical- or bio-reactor. In this talk I will focus on
material-science perspective on droplet microfluidics in which
individual compartments are treated as building blocks of larger
structures. It is known that concentrated emulsions behave like
soft-solids and exhibit both strong plasticity and
viscoelasticity. Microfluidics opens new perspectives on studying
these tissue-like materials at mesoscale: the possibility of
tracking individual droplets gives a unique insight into the
process of their self-assembly into ordered, reconfigurable
structures. In particular, we observe a variety of small, compact
clusters with well-defined point-group symetries. In presence of
external flow the structures get stretched into semi-solid
granular threads with long-range translational order. Finally, we
study relaxation dynamics of large spheroidal aggregates composed
of hundreds or thousands of droplets (10^2 </N/<10^4 ) and compare
the obtained results with similar experiments on cell aggregates
reported previously in the literature. We try to draw possible
mechanistic analogies between droplet-based structures and actual
biological micro-tissues.
Chair: Dr Zbigniew Rozynek
Seminar language: English
/365/
Date: Friday 2018.02.09
Speaker: Dr Maciej Misiorny
Affilation: Zakład Fizyki Mezoskopowej, Wydział Fizyki UAM
Title: Spin-dependent transport of electrons trough molecular
junctions in the Kondo regime (Seminarium habilitacyjne)
Abstract: Nanojunctions containing individual impurities strongly
tunnel coupled to leads have proven to be an excellent test-bed
for studying quantum many body effects in electronic transport,
among which the Kondo effect is one of the most prominent ones.
The role of such impurities can be played, for instance, by
quantum dots, magnetic atoms or molecules. A proper understanding
of the effect of charge and spin correlations on electronic
transport is especially sought for devices based on large-spin
(S>1/2) impurities exhibiting spin anisotropy. This stems from the
fact that such systems are a suitable platform for applications in
emerging technologies for storage and processing information. In
this talk, I will address different effects that can arise in
strongly correlated spin-polarized transport through junctions
with spin-anisotropic impurities. Specifically, I will discuss the
influence of spin anisotropy on transport characteristics, as well
as demonstrate how to control spin anisotropy of an impurity with
the aid of spintronic exchange fields.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/364/
Date: Thursday 2018.02.08
Speaker: Prof. Frederic Paul
Affiliation: University of Rennes1/CNRS, Institute of Chemical
Sciences, France
Title: Redox-active Group |
Metal-Alkynyl Complexes: Toward
Molecules and Materials with Electro-switchable Optical
Properties
Abstract: Over the last decade, the design of molecular structures
allowing the control of a given property (electron transfer,
magnetism, catalysis) using an external stimulus, such as
electron-exchange, constitutes an important goal, both from the
fundamental and applied standpoint. The facile and reversible
M(II)/M(III) redox process exhibited by several Fe(II) and Ru(II)
σ-arylacetylides fragments of formula
"L4XM(C ≡ C-Ar)-" can conveniently be used to reach
molecular assemblies with large and redox-switchable third-order
nonlinear optical (NLO) properties such as 1 or 2 [1,2]. Finally,
attempts to extend this concept to fluorescence or two-photon
absorption, or to access related electroswitchable materials will
be reported.
[1] M. P. Cifuentes, M. G. Humphrey, J. P. Morall., M. Samoc, F.
Paul, T. Roisnel, C. Lapinte Organometallics. 2005, 24, 4280-4288
(and refs. cited).
[2] (a) Gauthier, N.; Argouarch, G.; Paul, F.; Toupet, L.;
Ladjarafi, A.; Costuas, K.; Halet, J.-F.; Samoc, M.; Cifuentes, M.
P.; Corkery, T. C.; Humphrey, M. G. Chem. Eur. J. 2011, 17, 5561.
(b) N. Gauthier , C. Olivier , S. Rigaut , D. Touchard , T.
Roisnel , M. G. Humphrey , F. Paul Organometallics 2007, 26,
1063.
[3] N. Gauthier, G. Argouarch, F. Paul, M. G. Humphrey, L. Toupet,
Ababou-Girard, S., H. Sabbah, P. Hapiot, B. Fabre, Adv. Mater.
2008, 20, 1952.
Chair: Prof. UAM Jacek Kubicki
Seminar language: English
/363/
Date: Wednesday 2018.02.7
Speaker: Dr Arkadiusz Matwijczuk
Affiliation: Department of Physics, University of Life Sciences in
Lublin
Title: Organizacja molekularna 1,3,4-tiadiazaoli z funkcją
2,4-dihydroksyfenylu w rozpuszczalnikach organicznych oraz w
układach modelowych o znaczeniu biologicznym
Abstract: [PDF] Wybrane do badań właściwości
fotofizycznych związki z grupy 1,3,4-tiadiazoli wykazują głównie
działanie neuroprotekcyjne, przeciwgrzybiczne oraz
antynowotworowe. Badania spektroskopowe związków wykonane metodami
spektroskopii molekularnej pozwoliły zaobserwować, w przypadku
części struktur w środowisku wodnym, bardzo interesujące zjawisko
podwójnej fluorescencji. Efekt ten może być indukowany zmianą pH
roztworów wodnych, temperatury oraz efektami agregacyjnymi. W
przypadku analogicznych pomiarów widm związków wykonanych w
różnych rozpuszczalnikach organicznych, obserwowano tylko
pojedyncze pasmo fluorescencji. Badania różnych analogów tej grupy
związków wykazały, że można indukować wyżej wymieniony efekt
również w rozpuszczalnikach oraz modelowych układach biologicznych
poprzez zmianę stężenia związku lub modyfikację jego podstawnika.
W wodnych roztworach metanolu o określonej kwasowości obserwowano
najczęściej dwa osobne, częściowo pokrywające się, pasma
fluorescencji. W oparciu o dane krystalograficzne i badania
fluorescencyjne monokryształów związków stwierdzono, że mogą one
przyjmować dwie konformacje w zależności od orientacji
przestrzennej grupy -OH znajdującej się w pozycji orto względem
pierścienia tiadiazolowego. W zależności od przyjmowanej
konformacji w widmach emisji obserwujemy efekt podwójnej
fluorescencji lub dwa częściowo pokrywające się pasma emisji.
Szereg badań wykonanych metodami spektroskopowymi takimi jak
technika RLS, pomiary czasów życia fluorescencji oraz pomiary widm
emisji i wzbudzenia fluorescencji wskazują, że w wyjaśnieniu
natury zaobserwowanych efektów fluorescencyjnych pomocna jest
zarówno wiedza na temat konformacji molekuł jak i występowania
efektów agregacyjnych w roztworze. Układ w którym cząsteczki
przyjmują konformację z grupą -OH z pierścienia rezorcylowego
ustawioną bliżej atomu azotu z pierścienia 1,3,4-tiadiazolowego
prawdopodobnie zwiększa możliwość wewnątrzmolekularnego
przeniesienia ładunku i powstawania słabego stanu elektronowego
związanego z tym przeniesieniem, prowadzącego w konsekwencji do
powstawania efektu podwójnej fluorescencji tych cząsteczek, co
potwierdzają obliczenia kwantowomechaniczne metodami [TD]DFT. Obie
obserwowane konformacje odpowiednio stabilizowane przypuszczalnie
może różnić też zdolność oddziaływań biologicznych. Warto
podkreślić, że badania biologiczne tej grupy związków wykazały
również grzybobójcze efekty synergistyczne z amfoterycyną B w
stosunku do kilku szczepów grzybów patogennych w hodowlach in
vitro.
Chair: Prof. Maciej Krawczyk
Seminar language: Polish
/362/
Data: poniedziałek 5.02.2018
Prelegent: Mgr Daria Larowska
Afiliacja: Zakład Fizyki Chemicznej, Wydział Chemii UAM
Tytuł: Fotokatalityczny rozkład wody w układach barwnik /tlenek
grafenu/ kompleks kobaltu.
Streszczenie: Konwersja energii słonecznej na energię w formie paliwa
wydaje się być jednym z najbardziej obiecujących sposobów na
zaspokojenie potrzeb energetycznych świata w przyszłości.
Szczególnie duże nadzieje pokładane są w rozkładzie wody (water
splitting) prowadzącym do gospodarki opartej na wodorze jako
podstawowym paliwie. Opracowanie taniej, wydajnej i szybkiej
metody produkcji wodoru, jest podstawowym warunkiem, który musi
być spełniony by wodór mógł zastąpić bieżące nośniki energii.
Obecne metody wykorzystywane do kierowanego światłem rozkładu wody
podzielone mogą zostać na trzy grupy: metody termochemiczne,
fotobiologiczne oraz fotokatalityczne. W ramach seminarium
omówiona zostanie koncepcja fotokatalitycznej dekompozycji wody w
układach barwnik/ tlenek grafenu/kompleks kobaltu – ich
charakterystyka, właściwości oraz metodologia badań. Powierzchnia
tlenku grafenu dzięki jego unikalnym właściwościom może zostać
sfunkcjonalizowana za pomocą cząsteczek oraz nanomateriałów.
Główna korzyść zastosowania takich hybryd wiąże się zachodzącym w
nich transportem elektronu od wzbudzonej cząsteczki barwnika do
katalizatora kobaltowego poprzez arkusz tlenku grafenu (GO), w
wyniku czego następuje redukcja protonów i utworzenie wodoru
cząsteczkowego.
Prowadzący: Prof. UAM Marcin Ziółek
Seminar language: Polish
/361/
Date: Friday 2018.02.2
Speaker: Dr Jadwiga Nieminuszczy
Affiliation: Division of Cancer Biology, Institute of Cancer
Research, London, UK
Title: EXD2 nuclease safeguards the genome against replicative
stress
Abstract: The maintenance of replication fork stability is
essential for faithful genome duplication and suppression of
carcinogenesis. In an effort to further our understanding of the
mechanism of replication fork repair we performed an analysis of
proteins recruited to DNA replication forks using the iPOND
technique. This analysis identified EXD2, a nuclease that we have
shown recently to promote DNA-end resection and homology-directed
repair1, as a novel factor present at replication forks. EXD2 is
required for efficient ATR activation and fork restart in response
to replicative stress. Moreover, purified recombinant EXD2 can
efficiently process synthetic DNA structures mimicking those that
are generated at stalled/collapsed replication forks. In keeping
with this, EXD2-deficient cells are sensitive to a plethora of
agents that interfere with replication fork progression. Failure
to timely complete DNA synthesis leads to the persistence of
under-replicated DNA, which can manifest as anaphase bridges,
53BP1 OPT domains and/or cause formation of micronuclei.
Consistent with EXD2’s role in promoting efficient genome
duplication, we observe that EXD2-deficient or EXD2-nuclease dead
cells display a significant increase in the frequency of all these
markers. Thus, our data identify EXD2 as a novel component of the
replication fork protection pathway. We propose that EXD2
processes stalled/collapsed replication forks and by doing so,
promotes efficient fork restart assuring accurate completion of
DNA replication.
[1] R. Broderick et al., EXD2 promotes homologous recombination by
facilitating DNA end resection, Nat Cell Biol 18, 271-280 (2016).
Chair: Dr Paweł Zawadzki
Seminar language: English
/360/
Date: Wednesday 2018.01.31
Speaker: Dr Piotr Korcyl
Affiliation: Wydział Fizyki, Astronomii i Informatyki Stosowanej
Uniwersytetu Jagiellońskiego
Title: Using perturbation theory for non-perturbative
calculations
Abstract: Nowadays many inputs of phenomenological models are
taken from lattice simulations of Quantum Chromodynamics. These
numerical methods, based on Monte Carlo techniques, always stress
their superiority against other approaches by arguing that all
steps of computations are from first principles and truly
non-perturbative. However many of the most precise results use in
one way or another perturbation theory. In this talk I will try to
explain the intertwinned relation between non-perturbative
simulations and perturbation theory and discuss some of the modern
techniques of getting perturbative results on a lattice.
Chair: dr hab. Krzysztof Cichy
Seminar language: English
/359/
Data: środa 24.01.2018
Prelegent: Prof. UAM Gotard Burdziński
Afiliacja: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
Tytuł: Osobliwości naukowe roślin
Streszczenie: W ramach seminarium zostaną omówione wybrane metody
obronne roślin takie jak szybki ruch związany ze składaniem liści,
wytwarzaniem substancji trujących, lub zapachu, który przywabia
owady drapieżne. Szczególna uwaga zostanie poświęcona roślinom
owadożernym, których ruch pułapkujący bywa zaskakująco szybki (w
czasie ok. 3 ms u Ultricularia inflata), co wymaga stosowania
szybkich kamer (15000 klatek na sekundę). Omówione zostaną również
aspekty związane z powabnością kwiatów zarówno w zakresie akustyki
(liść o kształcie czaszy stanowi akustyczną echo-latarnię dla
nietoperzy zapylających kwiaty Marcgravia evenia), jak i optyki
(ubarwienie strukturalne płatków kwiatowych). Główną rolę
ubarwienia kwiatów pełnią barwniki, spośród których dla betalain
wykazaliśmy funkcję fotoprotekcyjną.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/358/
Data: poniedziałek 22.01.2018
Prelegent: Dr hab. Tomasz Grzyb
Afiliacja: Zakład Ziem Rzadkich, Wydział Chemii UAM
Tytuł: Up-konwersja w nanomateriałach domieszkowanych jonami
lantanowców: synteza, właściwości strukturalne i spektroskopowe
Streszczenie: Luminescencja jonów lantanowców (Ln3+) jest
tematem intensywnych badań, ze względu na rosnące zapotrzebowanie
domieszkowanych nimi materiałów w wielu dziedzinach. W odpowiednio
zaprojektowanych materiałach luminescencja jonów Ln3+ jest
wydajna i intensywna, a przede wszystkim możliwe jest uzyskanie
procesu konwersji energii w górę - up-konwersji (UC, ang.
up-conversion). Zjawisko to odpowiada nieliniowemu procesowi
absorpcji dwóch lub większej ilości fotonów w wyniku której
następuje emisja promieniowania o energii wyższej niż
zaabsorbowanego. Od kilku lat obserwuje się wzrost zainteresowania
nanocząstkami wykazującymi UC, głównie ze względów na szerokie
zastosowania w medycynie i biologii. Jednymi ze związków
charakteryzującymi się właściwościami umożliwiającymi uzyskanie UC
są nieorganiczne fosforany, wanadany i fluorki. Odpowiednia metoda
syntezy, środowisko reakcji oraz dobór reagentów umożliwiają
uzyskanie produktów o niewielkim rozmiarze krystalitów (< 50 nm).
Otrzymano szereg nanomateriałów opartych o związki typu REPO4,
REVO4, SrF2, LuF3, NaLuF4 oraz MRE2F7 (gdzie M =
Ca, Sr, Ba; RE = Y, La, Gd, Lu), domieszkowanych jonami Yb3+
i Ho3+, Er3+, Tm3+, Tb3+ lub Eu3+.
Otrzymane produkty scharakteryzowano pod względem ich struktury i
morfologii oraz składu pierwiastkowego. Najważniejszym elementem
przeprowadzonych badań było określenie właściwości
spektroskopowych otrzymanych materiałów. W celu otrzymania pełnej
charakterystyki luminescencyjnej otrzymanych produktów wykonano
pomiary widm wzbudzenia (także w zakresie podczerwieni) oraz
emisji, a także zaników emisji oraz zależności intensywności
luminescencji od mocy (lub energii) promieniowania wzbudzającego.
Pozwoliło to na Poznańie procesów zachodzących w otrzymanych
materiałach, zaproponowanie mechanizmów tych procesów, a także na
optymalizację badanych układów pod względem intensywności
luminescencji.
Prowadzący: Prof. UAM Marcin Ziółek
Seminar language: Polish
/357/
Date: Wednesday 2018.01.17
Speaker: Prof. Matteo Rizzi
Affiliation: Johannes Gutenberg-Universität, Institut für Physik,
Mainz, Germany
Title: Exploring Interacting Topological Insulators with Ultracold
Atoms: the Synthetic Creutz-Hubbard Model
Abstract: Understanding the robustness of topological phases of
matter in the presence of strong interactions, and synthesising
novel strongly-correlated topological materials, lie among the
most important and difficult challenges of modern theoretical and
experimental physics. The synthetic Creutz-Hubbard ladder is a
paradigmatic model that provides a neat playground to address
these challenges, including the generation of flat bands as well
as of non-doubled Dirac dispersion relations. In [1], we present a
theoretical analysis of the competition between correlated
topological phases and orbital quantum magnetism in the regime of
strong interactions at half-filling. We predict topological
quantum phase transitions for weak and intermediate interactions
with different underlying conformal field theories (CFTs), i.e.
Dirac versus Majorana CFTs. In [2], we study the response of an
interacting system of Dirac-Weyl fermions confined in a
one-dimensional (1D) ring: we show that tuning of interactions
leads to a unique many-body system that displays either a
suppression or an enhancement of the Drude weight—the
zero-frequency peak in the ac conductivity—with respect to the
non-interacting value. Both studies are furthermore confirmed and
extended by extensive numerical simulations based on matrix
product states (MPS) and binary Tree Tensor Networks (bTTN).
Moreover we propose how to experimentally realize this model in a
synthetic ladder, made of two internal states of ultracold
fermionic atoms in a
one-dimensional optical lattice.
[1] J. Jünemann, et al., PRX 7, 031057 (2017)
[2] M. Bischoff, et al., arXiv:1706.02679
Chair: Dr Agnieszka Cichy
Seminar language: English
/356/
Data: Poniedziałek 2018.01.15
Prelegent: Prof. UAM Ireneusz Weymann
Afiliacja: Zakład Fizyki Mezoskopowej, Wydział Fizyki UAM
Tytuł: Seminarium profesorskie
Streszczenie: Podczas seminarium ogólnie omówię tematykę moich badań,
która dotyczy teoretycznej analizy własności transportowych
skorelowanych układów nanoskopowych. Następnie, bardziej
szczegółowo, przedstawię kilka najważniejszych zagadnień, którymi
zajmowałem się po uzyskaniu stopnia naukowego doktora
habilitowanego. W szczególności przedstawię rezultaty dotyczące
badania różnych egzotycznych stanów Kondo w złożonych układach
kropek kwantowych, omówię także badania dotyczące stanów
związanych Andreeva w hybrydowych układach nanoskopowych, a także
badania związane z kwazicząstkami Majorany.
Prowadzący: Prof. Adam Miranowicz
Seminar language: Polish
/355/
Data: Środa 2018.01.10
Prelegent: Prof. Marcin Molski
Afiliacja: Zakład Chemii Teoretycznej, Wydział Chemii UAM
Tytuł: Kwantowe Fenomenologiczne Uniwersalia
Streszczenie: Koncepcja fenomenologicznych uniwersaliów wprowadzona
przez Castorinę, Delsanto i Guiot (CDG) [1], umożliwia generowanie
funkcji i modeli opisujących ewolucję w czasie układów
biologicznych, takich jak organy, organizmy, ekosystemy, czy
nowotwory. W zależności od stopnia złożoności (nieliniowości)
można badane układy sklasyfikować jako U0, U1 i U2, którym
odpowiadają funkcje biologicznego wzrostu: eksponent (U0),
Gompertza (U1), Westa-Browna-Enquista, Richardsa i von
Bertalanffy’ego (U2). Referat prezentuje prostą modyfikację
klasycznego schematu CDG [2,3], która pozwala na uzyskanie
kwantowych rozwiązań równań Schrödingera i Feinberga-Horodeckiego
dla oscylatora harmonicznego oraz oscylatorów anharmonicznych,
reprezentujących klasy Q0, Q1 i Q2 fenomenologicznych
uniwersaliów. Uogólnione podejście CDG umożliwia również
wygenerowanie lokalnych i nielokalnych stanów koherentnych
oscylatorów, które minimalizują zasadę nieoznaczoności
Heisenberga: położenie-pęd i czas-energia. Analiza otrzymanych
wyników dowodzi [2,3], że przejście od rozwiązań kwantowych Qn do
klasycznych Un dla n=1,2 zachodzi dla stanu dysocjacji oscylatora.
Wtedy funkcje kwantowe przechodzą w klasyczne, otrzymane w
podejściu CDG, co uzasadnia nadaną im nazwę - rozwiązania
quasi-kwantowe. Należą do nich wszystkie najważniejsze
czasowo-zależne modele opisujące ewolucję układów biologicznych
oraz przestrzenno-zależne funkcje opisujące skumulowaną
dystrybucję obiektów, różniących się rozmiarem (np. średnicą
aksonów w włóknie nerwowym).
[1] P. Castorina, P. P.
Delsanto, C. Guiot, Physical Review Letters 96 (2006) 188701.
[2] M. Molski, Physics Letters A 381 (2017) 2629–2635.
[3] M. Molski, Physics Letters A 382 (2018) 79–84.
Prowadzący: Prof. Zbigniew Jacyna-Onyszkiewicz
Seminar language: Polish
/354/
Data: środa 20.12.2017
Prelegent: Dr inż. Leszek Kasprzyk
Afiliacja: Instytut Elektrotechniki i Elektroniki Przemysłowej,
Politechnika Poznańska
Tytuł: Analiza pracy magazynów energii w pojazdach elektrycznych
Streszczenie: W ramach seminarium zostaną omówione wybrane metody
modelowania pracy akumulatorów oraz superkondensatorów w stanach
dynamicznych, a także metody estymacji parametrów modelu.
Poruszona zostanie krótko problematyka energochłonności pojazdów
oraz metody doboru akumulatorów do zasięgu i dynamiki jazdy. W
referacie zaprezentowane zostaną również przykładowe wyniki badań
energochłonności pojazdu, analizy pracy akumulatorów oraz metody
wydłużenia żywotności akumulatorów z wykorzystaniem rozwiązań
hybrydowych.
Prowadzący: dr hab. J. W. Kłos
Seminar language: Polish
/353/
Date: Wednesday 2017.12.13
Speaker: Dr Agnieszka Cichy
Affiliation: Solid State Theory Division, Faculty of Physics, AMU
Title: Classical and quantum simulations with ultracold
4-component fermionic mixtures in optical lattices
Abstract: The impressive development of experimental techniques
in ultracold quantum degenerate gases of alkaline-earth-like atoms
in the last years has allowed investigation of strongly correlated
systems. Long-lived metastable electronic states in combination
with decoupled nuclear spin give the opportunity to study the
Hamiltonians beyond the possibilities of current alkali-based
experiments. Ytterbium is particularly convenient due to its large
number of bosonic and fermionic (e.g. Yb-173) isotopes with a wide
range of interaction strengths. In [1] we study finite-temperature
properties of ultracold four-component mixtures of
alkaline-earth-metal-like atoms in optical lattices that can be
effectively described by the two-band spin-1/2 Hubbard model
including Hund's exchange coupling term. Our main goal is to
investigate the effect of exchange interactions on
finite-temperature magnetic phases for a wide range of lattice
fillings. We use the dynamical mean-field theory approach and its
real-space generalization to obtain finite-temperature phase
diagrams including transitions to magnetically ordered phases. It
allows to determine optimal experimental regimes for approaching
long-range ferromagnetic ordering in ultracold gases. We also
calculate the entropy in the vicinity of magnetically ordered
phases, which provides quantitative predictions for ongoing and
future experiments aiming at approaching and studying long-range
ordered states in optical lattices. In [2] we study the
thermodynamic properties of four-component fermionic mixtures
described by the Hubbard model using the dynamical
mean-field-theory approach. Special attention is given to the
system with SU(4)-symmetric interactions at half filling, where we
analyze equilibrium many-body phases and their coexistence regions
at nonzero temperature for the case of simple cubic lattice
geometry. We also determine the evolution of observables in
low-temperature phases while lowering the symmetry of the
Hamiltonian towards the two-band Hubbard model. This is achieved
by varying interflavor interactions or by introducing the
spin-flip term (Hund's coupling). By calculating the entropy for
different symmetries of the model, we determine the optimal
regimes for approaching the studied phases in experiments with
ultracold alkali and alkaline-earth-like atoms in optical
lattices.
[1] A. Cichy, A. Sotnikov, Phys. Rev. A 93, 053624 (2016)
[2] A. Golubeva, A. Sotnikov, A. Cichy, J. Kuneš, W. Hofstetter,
Phys. Rev. B 95, 125108 (2017)
Chair: Prof. Maciej Krawczyk
Seminar language: English
/352/
Date: Monday 2017.12.11
Speakers: Dr Mateusz Gierszewski & M. Sc. Eng. Iwona
Grądzka
Affiliation: Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
Title: Wybrane zagadnienia konwersji energii słonecznej z
konferencji ICP i ISPPCC 2017
Chair: Prof. UAM Marcin Ziółek
Seminar language: Polish
/351/
Date: Wednesday 2017.12.06
Speaker: Dr Michał Michałowski
Affiliation: Astronomical Observatory, Faculty of Physics, Adam
Mickiewicz University in Poznań
Title: The first observation of radiation from colliding neutron
stars – the sources of gravitational waves
Chair: Prof. UAM Agnieszka Kryszczyńska
Seminar language: English
/350/
Date: Wednesday 2017.11.29
Speaker: Dr Jaroslaw Paturej
Affiliation: Institute of Physics, University of Szczecin
Title: How macromolecular architecture affects physical properties
of polymers
Abstract: [PDF] Significant progress in polymerization
techniques allows to synthesize macromolecules with complex, yet
precisely controlled structure. Three distinct examples are
branched bottlebrushes, star polymers and ring-like polymers.
During the talk I will demonstrate that variation of
macromolecular architecture affects structural, mechanical,
interfacial and frictional properties of polymers as compared to
conventional linear chains.
Chair: Prof. Adam Miranowicz
Seminar language: English
/349/
Date: Wednesday 2017.11.22
Speaker: Prof. Igor Lyubchanskii
Affiliation: Donetsk Physical and Technical Institute of the
National Academy of Sciences of Ukraine and Department of Physics
and Technology, Donetsk National University
Title: Static magneto-optic effects in photonic-magnonic crystals
Chair: Prof. Maciej Krawczyk
Seminar language: English
/348/
Date: Wednesday 2017.11.15
Speaker: Prof. Konstantin Guslienko
Affiliation: Universidad Del Pais Vasco/Euskal Herriko
Unibertsitatea, San Sebastian, Spain
Title: Skyrmion stability and dynamics in ultrathin magnetic dots
Chair: Prof. Maciej Krawczyk
Seminar language: English
/347/
Date: Tuesday 2017.11.14
Speaker: Dr Junghee Ryu
Affiliation: Centre for Quantum Technologies, National University of Singapore, Singapore
Title: Operational quasiprobabilities in quantum theory
Abstract: Negative probability was introduced by Feynman to address a mystery of quantum theory [1]. Since then there have been many studies based on such approach. But from the point of view of the operationalism, there are conceptual problems of interpreting such probability with respect to a given physical situation. In other words, the meaning of the negative values is not clear. Recently, an operational quasiprobabilities (OQs) are introduced for qudits as well as optical fields states [2,3]. Here, we will discuss how the OQs deal with those problems.
[1] R. Feynman, in Negative Probabilities in Quantum Mechanics, edited by B. Hiley and F. Peat (Routledge, London, 1987).
[2] J. Ryu, J. Lim, S. Hong, and J. Lee, Operational quasiprobabilities for qudit, Phys. Rev. A 88, 052123 (2013).
[2] J. Jae, J. Ryu, and J. Lee, Operational quasiprobabilities for continuous variables, Phys. Rev. A 96, 042121 (2017).
Chair: Dr hab. Paweł Kurzyński
Seminar language: English
/346/
Date: Thursday 2017.11.9
Speaker: Dr Koji Maruyama
Affiliation: Osaka City University, Osaka, and Waseda University,
Tokyo, Japan
Title: Hilbert space structure induced by limited access
Abstract: Having seen the possibility of controlling multi-body
quantum systems indirectly, as well as that of identifying the
entire Hamiltonian, now let us consider a more
fundamental/abstract problem. When our direct access, or the
number of (direct) control probes, to the system is limited, what
is the extent to which it can be identified/controlled? This is a
natural question, especially after realising that there are
(infinitely) many systems that cannot be distinguished via
restricted access. In our attempt to understand the intrinsic
origin of the indistinguishability, we have revealed the
characteristic structures of Hilbert space that is induced by the
limited access. The structure tells us what draws the line between
controllable and uncontrollable subsystems, which necessarily
leads to indistinguishability as well.
Chair: Prof. Adam Miranowicz
Seminar language: English
/345/
Date: Wednesday 2017.11.8
Speaker: Dr Koji Maruyama
Affiliation: Wolfram Research, Japan
Title: Machine Learning by Mathematica (Wolfram Language)
Abstract: The machine learning functionality has been
significantly augmented in Mathematica 11. There are a number of
functions that allow us to start machine learning quickly without
expertise in this field. At the same time, it provides us with a
rich set of components to build up more complex tools, such as
deep neural networks. I will show how Mathematica can be used to
carry out machine learning computations for various types of data
sets.
Chair: Prof. Adam Miranowicz
/344/
Date: Wednesday 2017.11.8
Speaker: Dr Koji Maruyama
Affiliation: Osaka City University, Osaka, and Waseda University,
Tokyo, Japan
Title: Two-qubit control suffices to efficiently perform quantum
computation on a spin chain
Abstract: Towards the full manipulation of multi-body quantum
systems, there are still a number of obstacles we have to
overcome. We would need some tricks when taming a complex quantum
system, contemplating what we can do and what we cannot. In this
talk, I will delineate a theoretical guiding principle for quantum
controllability, and will present a specific idea for controlling
a spin system with a highly limited access. Three important
issues, i.e., the controllability, the computability of pulse
sequence, and the time-scale of quantum computing operations, are
addressed and answered positively.
Chair: Prof. Adam Miranowicz
Seminar language: English
/343/
Date: Tuesday 2017.11.07
Speaker: Dr Taras Radchenko
Affiliation: Department of Solid State Theory, Institute for Metal Physics, National Academy
of Sciences of Ukraine, 03142 Kyiv, Ukraine
Title: Electronic and transport properties of (un)strained
graphene with structural defects: Numerical calculations
Abstract: The study deals with modelling electronic and transport
properties of unstrained and uniaxially deformed graphene with
structural imperfections: zero-dimensional (point) and
one-dimensional (extended) defects. Point defects are modelled as
resonant (neutral) adsorbed atoms or molecules, vacancies, charged
impurities, and local distortions. Extended (line) defects are
attributed to atomic steps and terraces in epitaxially-grown
graphene, and grain boundaries, quasi-periodic nanoripples or
wrinkles in polycrystalline (chemically vapor-deposited) graphene.
Results are obtained numerically using the quantum-mechanical
Kubo-Greenwood formalism along with tight-binding approach.
Calculated behaviours of electronic density of states and
conductivity indicate that deviations from perfection can be
useful: they make possible tailoring graphene's electrotransport
properties for achievement of new functionalities.
Chair: dr Mateusz Kempiński
Seminar language: English
/342/
Date: Monday 2017.11.06
Speaker: Dr Andriy Khobta
Affiliation: Unit “Responses to DNA Lesions”, Institute of
Toxicology, University Medical Center Mainz
Title: Exploiting synthetic DNA lesions to pinpoint the critical
repair pathways
Abstract: [PDF]
DNA damage is a well-recognised causal factor of gene dysfunction in cancers and age-related diseases. Because DNA of all living cells is constantly exposed to a variety of reactive endogenous metabolites and environmental toxicants, DNA damage can never be fully avoided and its complexity comprises dozens of structurally different DNA modifications ("DNA lesions"). Knowledge of the lesion-specific responses of cells is required to characterise hazards of exposure to specific genotoxic agents and, from the translational perspective, to identify molecular susceptibility markers and potential targets for personalised therapeutic interventions.
My team exploits synthetic nucleotide derivatives to understand harmful consequences of individual DNA lesions and the lesion-specific repair mechanisms. To model damage induced by food carcinogens, drugs, environmental toxicants and endogenous cellular mechanisms at specific nucleotide positions, we incorporate synthetic analogs of the respective DNA modifications as building blocks into functional reporter genes [1-2]. Delivered to human host cells, such gene constructs can be efficiently used to monitor functional consequences of defined DNA lesions (tolerance versus toxicity), to characterise determinants of damage recognition by individual repair pathways, and to identify redundancy and potential switch points between the pathways [3-7]. I will discuss some recent applications of vectors containing the elements of synthetic nucleic acids to address questions in the fields of DNA repair and epigenetics.
[1] Lühnsdorf B, et al. (2012) Analytical Biochemistry 425: 47-53
[2] Kitsera N, et al. (2011) Nucleic Acids Research 39: 5926-5934
[3] Kitsera N, et al. (2014) PloS One 9: e94405
[4] Allgayer J, et al. (2013) Nucleic Acids Research 41: 8559-8571
[5] Lühnsdorf B, Epe B, Khobta A (2014) The Journal of Biological Chemistry 289: 22008-22018
[6] Allgayer J, et al. (2016) Nucleic Acids Research 44: 7267-7280
[7] Kitsera N, et al. (2017) Nucleic Acids Research doi: 10.1093/nar/gkx718 [Epub ahead of print].
Chair: Dr Paweł Zawadzki
Seminar language: English
/341/
Date: Wednesday 2017.10.25
Speaker: Dr Paweł Zawadzki
Affiliation: Molecular Biophysics Division, Faculty of Physics, AMU
Title: Single-molecule imaging of DNA repair in single living
cells
Abstract: [PDF] Every single day an individual cell
must deal with ~10,000 lesions in order to prevent accumulation
of harmful mutations, which might lead to cancer. Understanding
the mechanism of DNA repair is therefore of central importance to
our understanding of cancer and for the development of new
therapeutics against it. Repair pathways are highly conserved, in
both prokaryotes and eukaryotes, and studying the simpler pathways
in bacteria provides key insight into the mechanism used by human
cells to repair damaged DNA. We apply an interdisciplinary
approach to understand the mechanistic details of DNA repair
pathways (Nucleotide Excision Repair, Mismatch Repair, Base
Excision Repair) in living Escherichia coli (and human cells in
near future). We use a combination of cutting-edge single-molecule
methods to elucidate how repair enzymes participate in removal of
damaged nucleotides. Firstly, live super-resolution microscopy
combined with single-particle tracking is used to study the
behaviour of individual proteins as they scan the genome and
repair damaged DNA. To complement this, we use cell biology,
genetics and TIRF microscopy to verify and extend the conclusions
established using a super-resolution microscopy. Together, this
will provide a comprehensive understanding of the bacterial repair
pathway, and constitute a starting point to understanding the way
mutations in human repair proteins contribute to the development
of cancer.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/340/
Data: środa 2017.10.18
Prelegent: Dr Anna Marciniak
Afiliacja: Obserwatorium Astronomiczne, Wydział Fizyki UAM
Tytuł: Pierścień wokół planety karłowatej Haumea oraz jej
rozmiary, kształt i gęstość z obserwacji zakrycia gwiazdowego
Streszczenie: Na seminarium omówione zostaną wyniki badań
opublikowane w ostatnim numerze Nature 550, 219
(2017)
w artykule pt. The size, shape, density and ring of the
dwarf planet Haumea from a stellar occultation.
Prowadząca: prof. UAM Agnieszka Kryszczyńska
Seminar language: Polish
/339/
Date: Thursday 2017.10.12
Speaker: Doc. Jan Soubusta
Affiliation: Institute of Physics of Academy of Science of the
Czech Republic, Joint Laboratory of Optics of PU and IP AS CR,
Olomouc, Czech Republic
Title: Experimental tests of coherence and entanglement
conservation
Abstract: In the year 2015, Svozilík and co-authors published a
paper [Phys. Rev. Lett. 115, 220501 (2015)] discussing migration
of coherence of the studied system between its subsystems. The
authors showed that the coherence is also linked to the
correlations between the subsystems. The authors mentioned a few
interesting examples, where it is possible to study conservation
of the maximal accessible coherence in the system. We want to
demonstrate the effect of migration of coherence of the system on
two experimental schemes implemented using polarization states of
photons. The first scheme is based on linear optical
controlled-phase quantum gate and the second scheme is utilizing
effects of nonlinear optics.
Chair: Prof. Adam Miranowicz
Seminar language: English
/338/
Date: Thursday 2017.10.12
Speaker: Doc. Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Building a quantum router for discrete photons using linear
optics
Abstract: The talk discusses our experimental implementation of a
linear-optical quantum router. This device allows single-photon
polarization-encoded qubits to be routed coherently into two
output modes. Routing is programmed by two identical control
qubits and over this procedure, the quantum information stored in
the state of the routed photon is not disturbed. The success
probability of our scheme can be increased up to 25% making it
the most efficient linear-optical quantum router known to this
date.
Chair: Prof. Adam Miranowicz
Seminar language: English
/337/
Date: Thursday 2017.10.12
Speaker: Dr Antonín Černoch
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Experimental characterization of photon-number noise in
Rarity-Tapster-Loudon-type interferometers
Abstract: We develop a simple model describing inherent
photon-number noise in Rarity-Tapster-Loudon-type interferometers.
This noise is caused by generating photon pairs in the process of
spontaneous parametric down-conversion and adding a third photon
by attenuating the fundamental laser mode to the single-photon
level. We experimentally verify our model and present resulting
signal-to-noise ratios as well as obtained three-photon generation
rates as functions of various setup parameters.
Chair: Prof. Adam Miranowicz
Seminar language: English
/336/
Date: Wednesday 2017.10.11
Speaker: Dr Alexander Mikkelsen
Affiliation: Faculty of Physics, Adam Mickiewicz University
Title: Droplets covered by particles: Physics and applications
Abstract: [PDF] Clay and colloidal particles of
nano- and micrometer size adsorb strongly at liquid interfaces
where they display a wide range of studies and applications
[1],[2], for instance to stabilize emulsions, in material
development and to encapsulate, store and release a range of
materials such as medicine, cells, food or oil. Structuring of
particles on droplets is a particularly hot topic these days with
increasing interest and efforts devoted to the synthesis of
functional colloidal capsules. Such capsules, with tailored
physical, chemical or morphological characteristics, can be used
as building blocks to prepare complex structures with advanced and
novel material properties [3]. The talk will demonstrate and
explain how weakly conductive (leaky-dielectric) droplets behave
when suspended in another weakly conducive fluid and subjected to
an external electric field. Especially how electrohydrodynamic and
eletrorheological effects in such droplets can be used to
structure and dynamically control colloidal particle assemblies at
droplet surfaces. This includes electric-field-assisted convective
assembly of jammed colloidal “ribbons”, electrorheological
colloidal chains confined to a two-dimensional surface and
spinning colloidal domains. In addition, the talk will demonstrate
the size control of “pupil” like openings in colloidal shells [4],
present a simple and robust method to assemble colloidal shells of
controlled heterogeneity [5] and discuss some of the many
applications for particle covered droplets.
[1] B. P. Binks, Curr. Opin. Colloid In. 7, 21 (2002).
[2]
C. Zeng, H. Bissig, and A. D. Dinsmore, Solid State Commun. 139,
547 (2006).
[3] B Bollhorst, T., K. Rezwan, and M. Maas,
Chemical Society Reviews, 46, 2091 (2017).
[4] P. Dommersnes,
Z. Rozynek, A. Mikkelsen, R. Castberg, K. Kjerstad, K. Hersvik,
and J. O. Fossum, Nat. Commun. 4, 2066 (2013).
[5] Z. Rozynek,
A. Mikkelsen, P. Dommersnes, and J. O. Fossum, Nat.Commun. 5, 3945
(2014).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/335/
Date: Wednesday 2017.10.4
Speaker: Dr Zbigniew Rozynek
Affiliation: Institute of Acoustics, Faculty of Physics, UAM
Title: Granular and colloidal 1D structures: Physics and
applications
Abstract: [PDF] The fabrication of 1D granular and
colloidal materials is of considerable interest as they offer
opportunities for a variety of electronic applications, including
granular conductors, flexible electronics for wearable devices,
electromagnetic energy transport, etc. These particle structures
can be assembled either from particle groups or from individual
particles. In this talk I will show structures composed of
individual microparticles. There are several methods for
fabricating particle structures, including lithography,
cluster-assisted assembly and colloidal polymerization,
pore-assisted assembly, and field-directed assembly in electro- or
magneto-rheological fluids. The latter is generally considered to
be a simple and effective approach to form particle structures.
Thou fast and efficient, the external field-driven approach
suffers from three major limitations to its applications, for
example in electronic-device manufacturing. First, the assembly
often takes place in a bulk liquid; it is difficult to remove the
bulk liquid and maintain the assembled structure intact. Second,
in principal only linear 1D structures can be formed along the
field lines and positioning of the formed structure is greatly
limited. Third, maintaining the formed structures normally
requires a continuous energy supply; once the external field is
turned off, the structures disintegrate. Within this talk, I will
present novel routes to overcoming these limitations, making it
possible to easily fabricate self-sustained 1D structures outside
of a dispersion.
For more details, see the following article: Formation of
printable granular and colloidal chains through capillary effects
and dielectrophoresis, Nature Communications 2017, 8, 15255
Chair: Prof. Maciej Krawczyk
Seminar language: English
/334/
Date: Wednesday 2017.09.27
Speaker: Dr Łukasz Laskowski
Affiliation: Department of Microelectronics and Nanotechnology,
Częstochowa University of Technology
Title: Practical application for porous silica template functional
nanomaterials
Abstract: [PDF] The presentation will be devoted to
novel functional nanomaterials precisely tailored for specific
applications. The materials are based on porous silica matrices
both in the form of powder and vertically aligned thin films.
Powdered SBA-15 silica activated by copper ions can play a role of
strongly antimicrobial specimen with restricted migration into
environment. Thin film form of silica matrices with vertically
aligned channels makes the materials highly applicative in
electronics or IT technologies. We consider three types of such
silica-templated materials for application as antimicrobial
specimen or electronics elements. Porous silica films containing
permanent magnetic specimen inside pores can be used for
fabrication of super-dense magnetic memory. When silica is
activated by individual molecular magnets in pores bottom the
material can play a role of layout of molecular neurons. Porous
silica thin layer containing strongly dipolar units have strong
non-linear optical (NLO) response, that can be tuned by means of
functional groups concentration variation.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/333/
Date: Monday 2017.09.25
Speaker: Prof. David Sherratt
Affiliation: Department of Biochemistry, University of Oxford, UK
Title: How one chromosome makes two
Abstract: [PDF] Chromosomes were first observed and
the process of their segregation in mitosis described by Walther
Flemming, working in Kiel, Germany, in 1878, but it was another 25
years before their role in inheritance was proposed. The
coordinated processes of chromosome replication, unlinking and
subsequent chromosome segregation underlie the life process.
Defects in these processes lead to genetic diseases and a
multitude of pathologies in humans, while interfering with these
processes is the basis of the action
of many antibiotics and anti-cancer agents.
My laboratory studies the molecular mechanisms of the action of
the molecular machines that act in these processes in the
bacterium E. coli by using a combination of in vivo and in vitro
biochemistry, quantitative single-molecule imaging and genetics.
The presentation will focus on the importance of eliminating
ensemble averaging wherever possible and in the challenges of
reconciling in vitro and in vivo experimental data and in building
them into a mechanistic framework.
Chair: Dr Paweł Zawadzki
Seminar language: English
/332/
Date: Thursday 2017.09.14
Speaker: Prof. Charles Henry Bennett
Affiliation: IBM Fellow at IBM Research, Thomas J. Watson
Research Center in Yorktown Heights, New York.
Title: Is there such a thing as private information?
Abstract: One of the original motivations for quantum information
theory was the use of quantum effects to protect the privacy of
classical communications. Yet the new theory, which has grown to
elegantly encompass all of classical informatics, has undermined
the very notion of classical private information, by showing that
it sits on a slippery slope between quantum information and public
information. Classical privacy survives only as a useful
approximation, since in principle any memory so well shielded that
it can hold classical data without the environment finding out can
also hold superpositions of the classical values, thereby serving
as a quantum memory. To recover a sharp notion of classical
privacy it suffices to consider scenarios in which some
information escapes to a place beyond the reach of one's
adversaries.
Biography: Prof. Bennett is one of the most acclaimed physicists
and one of the founding fathers of modern quantum information
theory. Among his many discoveries are: reversible computation,
explanation of Maxwell's demon paradox, quantum cryptography, and
quantum teleportation. He also created the foundations of
entanglement theory and quantum communication. Prof. Bennett is a
laureate of many awards including this year's Dirac Medal. See
Wikipedia
for more details.
Chair: Prof. Andrzej Grudka
Seminar language: English
/331/
Date: Friday 2017.09.8
Speaker: Dr Bernadeta Dobosz
Affiliation: Zakład Fizyki Medycznej, Wydział Fizyki, UAM
Title: Badanie metodą ESR fizycznych właściwości
funkcjonalizowanych nanocząstek magnetytu jako potencjalnych
nośników leków
Abstract: Nanomateriały cieszą się coraz większą popularnością w
różnych dziedzinach życia, również w medycynie. Na przykład
nanocząstki magnetyczne stosuje się w obrazowaniu MRI czy w
hipertermii. Szczególnie obiecujące jest ich wykorzystanie jako
nośniki leków w terapiach celowanych. Dzięki właściwościom
magnetycznym nanocząstek, stosując odpowiednie sekwencje pól
magnetycznych, można kontrolować ich ruch. Funkcjonalizowane
nanocząstki mogłyby dostarczać lek bezpośrednio do miejsca choroby
(stan zapalny, guz) omijając tkanki zdrowe. Wspomniane wcześniej
właściwości magnetyczne nanocząstek można badać metodą
elektronowego rezonansu spinowego (ESR). Otrzymuje się w ten
sposób wiele cennych informacji zarówno o rdzeniu magnetycznym
nanocząstki jak i jej powierzchni. Właściwości nanocząstek zależą
od wielu czynników takich jak pokrycie, dołączony materiał,
środowisko czy warunki zewnętrzne, w których się znajdują.
Wszystkie te zależności można badać metodą ESR. Stosując tę metodę
można również kontrolować jakość nanocząstek oraz śledzić ich
starzenie i agregację. Szczególne znaczenie pod kątem zastosowania
nanocząstek w terapiach celowanych ma zastosowanie ESR do
monitorowania dyfuzji nanocząstek wymuszonej obecnością pola
magnetycznego.
Chair: Prof. Maciej Krawczyk
Seminar language: Polish
/330/
Date: Wednesday 2017.09.6
Speaker: Dr Alexander Kvashnin
Affiliation: Skolkovo Institute of Science and Technology, Moscow,
Russia
Title: Computational materials discovery in various
dimensionalities
Abstract: Computational materials discovery is a new field of
science, and an ongoing scientific revolution. New methods have
for the first time enable systematic discovery of superior
materials on the computer – instead of the traditional
laboratory-based trial-and-error approach. This approach allows
scientists to predict and investigate new materials, new phenomena
in various dimensionalities, starting from the bulk and moving
towards the 2D materials, 1D materials and molecules, clusters.
Here the recent research on the computational search for new
functional materials will be discussed. Among the 2D materials,
particular attention is drawn to such films of atomic thickness as
graphene, its derivatives. In addition, many of non-carbon
materials, which has no layered counterparts in bulk, are found to
be layered graphitic-like in nanoscale. Such evidences related to
silicon carbide, zinc oxide and aluminum nitride. In the field of
bulk materials (single crystals, composites, etc.), the main
direction of theoretical material science is search for crystal
structure with optimal desired properties, such as hardness, band
gap, dielectric constant, etc. Using the evolutionary algorithm
implemented in the software package USPEX, it became possible to
predict stable compounds, their crystal structure using only data
on their chemical composition. In addition, we studied the surface
reconstruction of rutile-like RuO2, especially the most stable
(110) surface, which is highly important for catalysis, sensing
and charge storage applications.
Chair: Dr Piotr Graczyk
Seminar language: English
/329/
Date: Wednesday 2017.06.21
Speaker: Prof. Sergey Tarapov
(Corresponding member of the National Academy of Sciences of
Ukraine)
Affiliation: Institute for Radiophysics and Electronics of the NAS
of Ukraine, V. N. Karazin Kharkiv National University Kharkiv,
Ukraine
Title: Magnetic Metamaterials and Electron Magnetic Resonance at
Microwaves: Experiment, Fundamental and Design
Abstract: The results of experimental study of fundamental
features of magnetically controlled metamaterials at microwave
band are under discussion. Among them are: (1) the transformation
of right-handed medium into left-handed medium and electrodynamic
analogs of Tamm states; (2) the left-handed properties (controlled
negative refraction) of semiconductor–ferrite composites; (3)
formation of backward wave in the chiral magnetoactive medium; and
(4) photonic crystals and magnetophotonic crystals. The possible
technological implementations of metamaterials are described.
Besides the special experimental equipment, designed for study
both magnetic microwave metamaterials and electron
spin/magnetic resonance in nanocomposites both at room and very
low temperatures (0.3-300 K) are presented. Also the results of
Electron Spin Resonance experimental research of spin dynamics in
magnetic nanodots and nanostrips ensembles at T = 4.2-300K are
discussed.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/328/
Date: Wednesday 2017.06.14
Speaker: Prof. IF PAN dr hab. Tomasz Sowiński
Affiliation: Institute of Physics of the Polish Academy of
Sciences, Warsaw, Poland
Title: Mass-imbalanced mixtures of several ultra-cold fermions in
one-dimensional traps
Abstract: With recent experiments on several particles confined
in a one-dimensional optical traps quantum engineering has entered
a completely new, so far unexplored, area of strongly correlated
quantum systems. Apart from a few exceptions, it has commonly been
assumed that particles of different kinds have the same mass and
the main impact on properties of the system comes from an
imbalance of the number of particles. In contrast, in my talk I
will focus on the system of a few ultra-cold fermions of different
masses. I will show that the mass difference between different
fermionic components leads to the specific spatial fragmentation
in one of the components. Although the mechanism predicted is
universal with respect to the number of particles, the
fragmentation occurs, depending on the shape of the confinement,
for either the lighter or the heavier component. In consequence,
the system may undergo a kind of critical transition that is
induced by an adiabatic change of the external potential.
Chair: Prof. Adam Miranowicz
Seminar language: English
/327/
Date: Wednesday 2017.06.14
Speaker: Dr Michał J. Michałowski
Affiliation: Obserwatorium Astronomiczne, Wydział Fizyki, UAM
Title: Dust in the distant Universe
Abstract: I will summarize what we have learned about dusty
galaxies at large distances from Earth. The characterization of
their properties is crucial to understand the evolution of the
Universe, because dust absorbed and re-emitted in the infrared
50% of stellar emission ever produced in the Universe. First, I
will show my effort in obtaining the largest so far ( 2000
objects) sample of galaxies selected by their infrared emission. I
will discuss their redshifts, stelar masses and star formation
rates. These properties provide important tests of cosmological
models. Then I will show how we can learn in what way the large
masses of dust in the distant Universe were produced: either by
asymptotic giant branch stars, by supernovae, or by dust grain
growth in the interstellar medium. The knowledge of how early
galaxies could produce their dust is important from the point of
view of further evolution, because dust is enabling formation of
molecular gas, the fuel for star formation.
Chair: Prof. Maciej Krawczyk
Seminar language: Polish
/326/
Data: Piątek, 9 czerwca 2017
Prelegent: Dr Jędrzej Kociński
Afiliacja: Zakład Akustyki Pomieszczeń i Psychoakustyki, WF UAM
Tytuł: Testy zrozumiałości mowy jako uniwersalne narzędzie do
badania zmysłu słuchu oraz wybranych układów fizycznych
Streszczenie: Ocena zrozumiałości mowy jest nie tylko narzędziem
diagnostycznym wykorzystywanym w protetyce słuchu, ale może
dostarczyć wielu istotnych informacji na temat funkcjonowania
układu słuchowego człowieka, a także może być wykorzystana w
badaniach innych procesów w centralnym układzie słuchowym. Co
więcej, metody oceny zrozumiałości mowy posłużyć mogą także do
analizy funkcjonowania układów fizycznych począwszy od aparatów
słuchowych poprzez pomieszczenia, na różnego typu algorytmach
przetwarzania sygnałów
skończywszy.
Przedstawione do oceny publikacje wskazują na uniwersalność badań
wykorzystujących zrozumiałość mowy w ocenie funkcjonowania zarówno
układu słuchowego, jak i centralnego układu nerwowego. Co więcej
prace te potwierdzają istotność, a wręcz konieczność
wykorzystywania testów zrozumiałości mowy do oceny innych układów,
w których ta zrozumiałość gra istotną rolę, jak np. algorytmy
separujące sygnały, czy pętle indukcyjne wykorzystywane do poprawy
zrozumiałości mowy u użytkowników aparatów słuchowych. Testy te
posłużyć mogą także do weryfikacji obiektywnych parametrów
służących jako predyktory zrozumiałości mowy (np. Speech
Transmission Index, STI) lub jej poprawy (np. poprawa stosunku
sygnału do szumu, SNR). Warto podkreślić, że wyniki prac otrzymano
stosując najnowsze i najdokładniejsze metody pomiaru zrozumiałości
mowy wnosząc tym samym nowe dane zarówno pod względem jakościowym,
jak i pod względem obszarów badawczych.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/325/
Date: Wednesday 2017.06.7 at 13:00
Speaker: Prof. Oleksandr V. Dobrovolskiy
Affiliation: Physics Department, V. N. Karazin Kharkiv National University, Ukraine, and
Physikalisches Institut, Goethe University Frankfurt am Main,
Germany
Title: Focused electron beam-induced deposition of magnetic
nanostructures
Abstract: Focused electron beam induced deposition (FEBID) is a
direct-write approach for the fabrication of 2D and 3D
nanostructures in various materials research areas. These comprise
superconductors, magnetic materials, multilayer
structures, and various sensor applications. FEBID is based on the decomposition of organo-metallic precursor
gas molecules which are injected into the chamber of a scanning
electron microscope. The deposition of the material takes place at
those points where the electron beam dwells for a longer time in
accordance with a pre-defined pattern. A post-growth processing of
FEBID structures allows one to modify their compositional,
structural and magnetic properties. In this talk, a general introduction to the basics of FEBID will
be given, with an outline of available FEBID materials. A
particular focus will be on Co-based FEBID nanostructures and
tuning their magnetic properties on the lateral mesoscale by an
area-selective post-growth processing. Further, exemplary 3D FEBID
nanostructures will be presented and the perspectives of their use
in fluxonic, photonic, and magnonic metamaterials will be
outlined.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/324/
Date: Friday 2017.06.2, 11:30
Speaker: Prof. Ryszard Jankowiak
Affiliation: Department of Chemistry and Department of Physics,
Kansas State University, Manhattan, KS, USA
Title: Excitonic structure and dynamics in various photosynthetic
antenna protein complexes: hole-burning and modeling studies
Abstract: [PDF] Low temperature (high-resolution)
hole-burning (HB) spectroscopy and modeling studies of various
optical spectra of photosynthetic complexes provide new insight
into excited state electronic structure and dynamics. The
following complexes will be briefly discussed: 1) The CsmA–
bacteriochlorophyll α complex from C. tepidum. In this
case, in contrast to literature data, an alternative
structure is proposed for the baseplate; 2) The FMO antenna
complex from C. tepidum and its mutants. Using an experimentally
determined shape for the spectral density for the lowest- energy
state (Jph(ω)), simulated optical spectra are obtained
from structure-based calculations for the FMO trimer. For higher
energy pigments, the effect of a broader Jph(ω) shape
with a different S factor and/or variable Γinh are also
tested for comparison. I will demonstrate that in order to
properly describe various low-temperature optical spectra, a
downward uncorrelated excitation energy transfer (EET) between
trimer subunits must to be taken into account. That is, after
light induced coherences vanish within each monomer, uncorrelated
EET between the lowest exciton levels of each monomer takes place
due to static structural inhomogeneities in the trimer. The
information gained provides new insight into disorder, excitonic
structure, EET dynamics and mutation induced changes induced via
site directed mutagenesis; and 3) The B800-850 LH2 antenna complex
from Alc.vinosum, which exhibits an unusual spectral splitting of
the B800 absorption band. Here, we propose that various protein
conformations lead to either strong or weak hydrogen bonds between
the protein and B800 pigments.
Biography: Ryszard Jankowiak is a Distinguished Professor of
Chemistry and Ancillary Distinguished Professor of Physics at
Kansas State University, Manhattan, KS, USA. He is also affiliated
with the Photosynthetic Antenna Research Center, Washington
University, Saint Louis, MO. He has published over 230
papers in various areas of physical chemistry, toxicology,
chemical carcinogenesis, physics, and biophysics. Currently he
studies photosynthetic reaction centers and various antenna
pigment complexes (including mutants) of green plants/algae and
photosynthetic bacteria using solid-state low-temperature
(laser-based) spectroscopies and theoretical modeling.
Research Gate score: 43.2; over 5,340 citations. H INDEX 39.
Contact phone numbers: +(785) 532- 6785 or +(785) 410-4163.
Chair: Prof. UAM dr hab. Krzysztof Gibasiewicz
Seminar language: English
/323/
Date: Thursday 2017.06.01
Speaker: Prof. Hendrik Ohldag
Affiliation: A Distinguished Lecturer of the IEEE Magnetics
(2017), SLAC National Accelerator Laboratory, Menlo Park,
California, USA
Title: Ultrafast and Very Small: Discover Nanoscale Magnetism With
Picosecond Time Resolution Using X-Rays
Abstract: Today’s magnetic device technology is based on complex
magnetic alloys or multilayers that are patterned at the nanoscale
and operate at gigahertz frequencies. To better understand the
behavior of such devices one needs an experimental approach that
is capable of detecting magnetization with nanometer and
picosecond sensitivity. In addition, since devices contain
different magnetic elements, a technique is needed that provides
element-specific information about not only ferromagnetic but
antiferromagnetic materials as well. Synchrotron based X-ray
microscopy provides exactly these capabilities because a
synchrotron produces tunable and fully polarized X-rays with
energies between several tens of electron volts up to tens of
kiloelectron volts. The interaction of tunable X-rays with matter
is element-specific, allowing us to separately address different
elements in a device. The polarization dependence or dichroism of
the X-ray interaction provides a path to measure a ferromagnetic
moment and its orientation or determine the orientation of the
spin axis in an antiferromagnet. The wavelength of X-rays is on
the order of nanometers, which enables microscopy with nanometer
spatial resolution. And finally, a synchrotron is a pulsed X-ray
source, with a pulse length of tens of picoseconds, which enables
us to study magnetization dynamics with a time resolution given by
the X-ray pulse length in a pump-probe fashion. The goal of this
talk is to present an introduction to the field and explain the
capabilities of synchrotron based X-ray microscopy, which is
becoming a tool available at every synchrotron, to a diverse
audience. The general introduction will be followed by a set of
examples, depending on the audience, that may include properties
of magnetic materials in rocks and meteorites, magnetic inclusions
in magnetic oxides, interfacial magnetism in magnetic multilayers,
and dynamics of nanostructured devices due to field and current
pulses and microwave excitations.
More information at www.ieeemagnetics.org
Chair: Prof. Maciej Krawczyk
Seminar language: English
/322/
Date: Wednesday 2017.05.31 at 13:00
Speaker: Prof. Richard J. Spontak
Affiliation: Departments of Chemical |
Biomolecular Engineering
and Materials Science |
Engineering North Carolina State
University Raleigh NC 27695
Title: Biomimicry with Block Copolymers: Directed Self-Assembly
via Crystallization or Chemical Coordination
Abstract: Spontaneous self-assembly of block copolymer (BCP)
molecules in a block-selective solvent typically results in the
formation of micelles possessing a classical spherical morphology.
Inclusion of a crystallizable block in the copolymer promotes
crystallization-driven self-assembly (CDSA), yielding anisotropic
cylindrical micelles that can, after additional processing,
possess a remarkably narrow length polydispersity. Anisotropic
nanoparticles prepared from BCPs are of growing importance as
building blocks for the creation of a wide range of synthetic
hierarchical materials. However, the assembly of such structural
units is generally limited to the use of amphiphilic interactions.
In addition to CDSA to generate single cylindrical micelles,
reversible coordination-driven hierarchical self-assembly can be
used to produce micron-scale fibers and macroscopic films based on
the association of low-polydispersity cylindrical BCP micelles. In
this case, coordination of palladium metal centers to phosphine
ligands immobilized within the soluble coronas of BCP micelles is
observed to induce intermicellar crosslinking, affording stable
linear fibers comprised of micelle subunits in a staggered
arrangement. The mean length of the fibers can be readily varied
by altering the micelle concentration, reaction stoichiometry or
aspect ratio of the micelle building blocks. Furthermore, the
fibers aggregate upon drying to form robust, self-supporting
macroscopic micelle-based thin films with useful mechanical
properties that are analogous to crosslinked polymer networks, but
on a significantly longer length scale. A comparable hierarchical
self-assembly strategy yields toroidal micelles that combine to
form micron-scale superstructures. Addition of a crystallizable
BCP to a solution of a toroid-forming BCP results in the formation
of toroidal multimicelles, as well as single-layer hexagonal
arrays of connected toroids. By controlling the ability of the
BCPs to form hydrogen bonds through the introduction of hydroxyl
groups on the crystallizable BCP and the accompanying level of
solvophobic interactions, the BCPs can spontaneously self-assemble
to form 3D periodic mesoporous superstructures. Studies such as
these demonstrate that self-assembly of BCPs into discrete,
non-spherical nanostructures can be scaled from the "ground-up" to
yield materials with intriguing morphologies and potentially
unique properties.
Chair: Prof. Michał Banaszak
Seminar language: English
/321/
Data: piątek 2017.05.26
Prelegent: Dr Oskar Baksalary
Afiliacja: Quantum Physics Division, Physics Faculty, AMU
Tytuł: Rachunek macierzowy wobec zagadnień z zakresu fizyki -
reprezentacje odwrotności Moore'a-Penrose'a
Streszczenie: Pojęcie odwrotności Moore'a-Penrose'a macierzy odgrywa
ważną rolę w rozmaitych dziedzinach nauki. Bodajże najlepiej znany
przykład jego zastosowania dotyczy metody najmniejszych kwadratów
wykorzystywanej w większości obszarów badań naukowych odwołujących
się do metod matematycznych. Jednak przykłady zastosowań
odwrotności Moore'a-Penrose'a obejmują także inne zagadnienia, z
których wiele wywodzi się z fizyki. W trakcie seminarium
przedstawione zostaną rezultaty odnoszące się do odwrotności
Moore'a-Penrose'a rozmaitych funkcji macierzy ze szczególnym
naciskiem położonym na alternatywne sposoby reprezentowania tego
pojęcia. Wśród poruszonych zagadnień znajdą się m.in.: odwrotności
Moore'a-Penrose'a macierzy zmodyfikowanej macierzą rzędu 1,
odwrotność core (i jej związki z odwrotnościami
Moore'a-Penrose'a, Botta-Duffina i grupową), a także unitarnie
niezmiennicze miary rozseparowania przestrzeni wektorowych. W
obrębie zainteresowania będą przy tym klasy macierzy
hermitowskich, idempotentnych i EP.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/320/
Date: Thursday 2017.05.25
Speaker: Dr Su-Yong Lee
Affiliation: School of Computational Sciences, Korea Institute for
Advanced Study, Seoul, Korea
Title: Single-photon non-locality test using feasible measurement
setups
Abstract: We test non-locality of a single-particle under feasible
measurements, such as on-off and homodyne detections along with
displacement and squeezing operations. On-off detection exhibits
the existence of intensity of light by its click event, and
homodyne detection shows the information on the phase of light by
measuring intensity difference. We find that a single-particle
entangled state can violate the CHSH inequality up to 2.782 when
all four measurements are squeezed-and-displaced on-off
detections.
Chair: Dr hab. Paweł Kurzyński
Seminar language: English
/319/
Date: Wednesday 2017.05.17 at 13:00
Speaker: Prof. dr Mustafa Serkan Soylu
Affiliation: Department of Physics, University of Giresun, Turkey
Title: An example of combined experimental-theoretical
characterization of metal (Nickel (II)) complex with neutral
ligand
Abstract: [PDF] The term of computational chemistry may
be defined as the mathematical description and numerical
computation of molecular structures. The term computational
chemistry is generally used when a mathematical method is
sufficiently well developed that it can be automated for
implementation on a computer. Computational chemistry has become a
useful way to investigate materials that are too difficult to find
or too expensive to purchase. It also helps chemists make
predictions before running the actual experiments so that they can
be better prepared for making observations. It’s also useful ways
to explain of spectroscopic results of molecular structures. The
mathematical description of the molecular structures based on the
Quantum mechanics rules. Because of the Quantum mechanics (QM) is
the correct mathematical description of the behaviour of electrons
and thus of molecular structures. In theory, QM can predict any
property of an individual atom or molecule exactly. In practice,
the QM equations have only been solved exactly for one electron
systems. A myriad collection of methods has been developed for
approximating the solution for multiple electron systems. These
approximations can be very useful, but this requires an amount of
sophistication on the part of the researcher to know when each
approximation is valid and how accurate the results are likely to
be. In my presentation, I intend to give you some information
about a few examples of our work entitled “Combined
experimental–theoretical characterization of chelidamate nickel
complex with 4-methylpyrimidine”. A new chelidamate complex of
nickel (II) ion was synthesized and characterized by
single-crystal X-ray diffraction, UV–Vis and FT-IR spectroscopy.
Theoretical calculations have been carried out by using
Hartree–Fock (HF)/6-31G (d) and Density Functional Theory
(DFT)/6-31+G (d). HOMO–LUMO energies, absorption wavelengths and
excitation energy were computed by time dependent DFT (TD-DFT)
method with polarizable continuum model. The observed FT-IR
vibrational frequencies are analysed and compared with
theoretically predicted vibrational frequencies.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/318/
Data: piątek 2017.05.12, 12:00
Prelegent: Dr Aleksandra Trzaskowska
Afiliacja: Zakład Fizyki Kryształów, WF UAM
Tytuł: Dyspersja fal powierzchniowych w strukturach fononicznych
badana metodą wysoko rozdzielczej spektroskopii Brillouina
Streszczenie: Przedstawiono wyniki badania wysokorozdzielczą
spektroskopią Brillouina dyspersji fal powierzchniowych w różnego
typu kryształach fononicznych. Powierzchniowe własności sprężyste
badanych próbek symulowano, w każdym przypadku, metodą elementów
skończonych (FEM). Dla jednowymiarowych kryształów fononicznych
pokazano wpływ periodyczności sieci na amplitudę fal
powierzchniowych. W przypadku kryształów dwuwymiarowych
zaobserwowano istnienie przerwy energetycznej a w strukturach
wyspowych wykazano także istnienie modów „oddychających". Ciekawe
własności aplikacyjne obserwowano w przypadku zmodyfikowanej
dwuwymiarowo struktury 1D.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/317/
Data: środa 2017.05.10 at 13:00
Prelegenci: Mgr Justyna Łodyga i Prof. UAM dr hab. Andrzej Grudka
Afiliacja: Quantum Electronics Division, Physics Faculty, AMU
Tytuł: Zmarszczki czasoprzestrzeni, czyli fale grawitacyjne
Streszczenie: 11 lutego 2016 roku międzynarodowy zespół naukowców
poinformował o pierwszym w historii zarejestrowaniu fal
grawitacyjnych. Fale te zostały zarejestrowane w Stanach
Zjednoczonych równocześnie przez dwa detektory LIGO (Laser
Interferometer Gravitational-wave Observatory), oddalone od siebie
o ponad
3 tys. kilometrów.
Podczas seminarium, w elementarny sposób omówimy różnice między teorią
grawitacji Newtona a elektrodynamiką. Następnie przedstawimy w jaki sposób
Einstein zmodyfikował teorię Newtona i omówimy podstawowe eksperymenty
potwierdzające jego teorię grawitacji. Wyjaśnimy, dlaczego w teorii tej,
podobnie jak w elektrodynamice, występują rozwiązania falowe. Na koniec omówimy
wspomniany na początku eksperyment, w którym zaobserwowano fale grawitacyjne.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/316/
Data: środa 2017.05.10, 11:00
Prelegent: Dr Krzysztof Cichy
Afiliacja: Instytut Fizyki Teoretycznej, Uniwersytet Goethego we Frankfurcie, Niemcy
oraz Zakład Fizyki Kwantowej, WF UAM
Tytuł: Chromodynamika kwantowa na sieci z fermionami twisted
mass
Streszczenie: Chromodynamika kwantowa (QCD) jest obowiązującą teorią
oddziaływania silnego. W reżimie niskoenergetycznym stała
sprzężenia QCD jest duża i nie jest możliwe zastosowanie rachunku
zaburzeń. Jedynym podejściem dającym ilościowe przewidywania z
pierwszych zasad jest sformułowanie QCD na Euklidesowej sieci
czasoprzestrzennej oraz obliczenie odpowiednich całek po
trajektoriach numerycznie, używając algorytmów Monte Carlo.
Seminarium to poświęcone będzie wynikom uzyskanym przy użyciu
jednej z najważniejszych dyskretyzacji działania fermionowego,
tzw. twisted mass. Przedstawimy wnioski dotyczące
nieperturbacyjnej renormalizacji, a także spektralnych, chiralnych
i topologicznych własności QCD.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/315/
Date: Wednesday 2017.04.26 at 13:00
Speaker: Dr Ravindra Chhajlany
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Control of many body features in synthetic and real
materials: selected topics
Abstract: Rapid and major advances in the field of ultracold gases
in optical lattices as well as ultra-fast pump-probe spectroscopy
in solids are allowing unprecedented control of strongly
correlated quantum many body systems with light. In this talk we
shall present two examples of such control. In the optical lattice
setting, we describe a new system that can be implemented in
current state-of-the-art experiments with two species of fermions
and tuned to extreme parameter regimes. This system exhibits a
combination of interesting features: hidden string order, hole
superconducting correlations and non-trivial excitations. In the
condensed matter settings, we outline a recent experiment
demonstrating the switching of orbitally ordered domains in the
prototypical manganite LSMO (La0.5Sr1.5MnO4) with non-resonant
THz light and provide a simplified model description of the
observed effect.
Chair: Prof. Adam Miranowicz Seminar language: English
/314/
Date: Wednesday 2017.04.12, 14:00
Speaker: Dr Joanna Raczkowska
Affiliation: Wydział Fizyki, Astronomii i Informatyki Stosowanej,
Uniwersytet Jagielloński, Kraków
Title: Innovative polymer coatings for controlled
interactions with proteins and cells
(Innowacyjne pokrycia polimerowe do kontroli oddziaływań z białkami i komórkami)
Abstract: [PDF] In recent years the growing
attention is paid to a broad interdisciplinary 'bio-interface
science', on the border between physics and biology, focused at
the design of novel, innovative coatings enabling to use polymer
materials with the controlled physicochemical properties for
biomedical applications. The biocompatibility of the material and
possibility of its biomedical applications is determined by its
interactions with biological material, dependent on
physicochemical properties of the surface, such as chemical
composition, wettability, topography or elasticity. In the
lecture, the idea of controlling the physicochemical properties of
the substrate in the way enabling controlled interactions between
the polymer coatings and the biological material will be
presented. The results of performed experiments regarding the
impact of substrate elasticity on the behavior of cancerous cells
at different stage of cancer progression as well as the design and
complex characterization of thermoresponsive, intelligent polymer
coatings with controlled physicochemical properties will be
reported. Conducted studies cover numerous steps, including the
design and fabrication of polymer coatings with controlled
properties, their complex characterization, as well as
biocompatibility tests for both, proteins and cells. The obtained
results enable deeper understanding of the complex interactions on
the bio-interface between the surface and biological material.
Streszczenie: W ostatnich latach jednym z głównych kierunków rozwoju
nauk z pogranicza fizyki polimerów, biologii i medycyny jest
poszukiwanie innowacyjnych rozwiązań pozwalających na
wykorzystanie pokryć polimerowych o kontrolowanych właściwościach
fizykochemicznych do zastosowań biomedycznych. O możliwościach
aplikacyjnych podłoża decyduje jego zdolność do oddziaływania z
materiałem biologicznym, determinowana przez właściwości
powierzchni, takie jak skład chemiczny, zwilżalność, topografia
czy elastyczność. W referacie zostanie przedstawione zagadnienie
możliwości kontroli właściwości fizykochemicznych podłoża w celu
uzyskania kontrolowanych oddziaływań pokryć polimerowych z
białkami i komórkami. Opisane zostaną wyniki badań dotyczących
wpływu elastyczności podłoża na zachowanie komórek nowotworowych o
różnym stopniu zaawansowania oraz tworzenia i kompleksowej
charakterystyki termoprzełączalnych inteligentnych pokryć
polimerowych. Badania te obejmowały szereg etapów, poczynając od
zaprojektowania i wytworzenie podłoży o zadanych właściwościach,
poprzez kompleksową charakterystykę ich właściwości
fizykochemicznych aż do testów biokompatybilności, prowadzonych
zarówno dla białek, jak i dla komórek. Otrzymane wyniki pozwalają
na głębsze Poznańie skomplikowanych oddziaływań zachodzących
pomiędzy podłożem a materiałem biologicznym.
Chair: Prof. Maciej Krawczyk
Seminar language: Polish
/313/
Date: Wednesday 2017.04.05, 14:00
Speaker: Prof. Miroslav Holecek and mgr Milada Krejcova
Affiliation: Faculty of Applied Sciences, Department of Mechanics,
University of West Bohemia, Pilzno
Title: Maxwell demon, Landauer principle, and stochastic processes
focused on molecular motors
Chair: dr hab. Przemysław Chełminiak
Seminar language: English
/312/
Date: Wednesday 2017.04.05, 12:00
Speaker: Dr Pavel Baláž
Affiliation: Charles University, Faculty of Mathematics and
Physics, Department of Condensed Matter Physics, Prague, Czech
Republic
Title: Magnetic properties of Bi2Se3 3D topological
insulator doped by Mn atoms: theory and numerical simulations
Abstract: Electric conductivity [1] and ferromagnetic Curie
temperature of bulk Mn-doped Bi2Se3 and Bi2Te3 3D
topological insulators are systematically studied by means of
atomistic Monte Carlo simulations. Exchange interactions between
the Mn magnetic moments have been calculated using ab initio
methods. Tight-binding linear muffin-tin orbital method has been
employed, together with the coherent potential approximation to
describe the high degree of disorder in the system. Spin-orbit
interaction is included in the ground state calculation. In the
studied materials Mn atoms might either replace a Bi atom
(substitutional position) or fill an empty position in van Der
Waals gap between the atomic layers (substitutional position). It
has been shown that exchange interaction between Mn magnetic
moments might lead to a ferromagnetic phase transition. The Curie
temperature is shown to be significantly dependent on the
concentration of Mn atoms in substitutional and interstitial
positions.
[1] K. Carva, J. Kudrnovský, F. Máca, V. Drchal, I. Turek, P.
Baláž, V. Tkáč, V. Holý, V. Sechovský, J. Honolka, Phys. Rev. B
93, 214409 (2016).
Chair: Prof. Maciej Krawczyk
Seminar language: English
/311/
Date: Friday 2017.03.31 at 13:00
Speaker: M.Sc. Karam Chand
Affiliation: University of New South Wales, Canberra Campus,
Australia and Advanced Research Center, Saudi Aramco, Kingdom of
Saudi Arabia.
Title: Quantum channel capacity under realistic circumstances
Abstract: Quantum channels can be used to transfer both classical
and quantum information. The capacity of a quantum channel is
defined by the upper bound of it transmission rate. The capacity
improvement of a quantum channel remains an open question. In this
presentation, I will discuss a systematic method to investigate
quantum channel capacity in spectral domain under stringent
constrained resources, particularly photons, which is then
apportioned under more realistic circumstances. Here, a classical
signal analysis methodology is used to match the power spectral
density of the signal to the spectrum of a squeezed channel
supported by a subthreshold optical parametric oscillator.
Furthermore, using water-filling algorithm, I will define and
declare the first time, the upper bound of the channel capacity of
a quantum channel under realistic practical assumptions. Following
on from that, I will establish the best signal-to-noise ratio and
bit-error-rate that can be achieved for a bipolar non-return to
zero digital signals imposed on the squeezed output of a
sub-threshold optical parametric oscillator, for given fixed
number of photons in the channel. For a range of parameters, I
will establish the circumstances under which the squeezed channel
can perform better than a classical channel (as supported by a
coherent state). Using these techniques, I will optimize the
capacity of a quantum channel for a given photon flux in the
channel. This also provides the machinery needed to design
experiments that would demonstrate quantum enhancement. Further
discussion, if one considers mismatched parameter regime, in fact
very importantly show how by increasing squeezing level decreases
quantum enhancement. I will also discuss how to use these ranges
of optimum parameters to design a quantum channel.
Chair: Prof. Adam Miranowicz
Seminar language: English
/310/
Date: Wednesday 2017.03.22, 12:00
Speaker: Dr hab. Adam Sawicki
Authors: Adam Sawicki and Katarzyna Karnas
Affiliation: Center for Theoretical Physics of the Polish Academy
of Sciences, Warsaw
Title: Universal quantum gates
Abstract: I will consider the problem of deciding if a finite set
of quantum one-qudit gates is universal, i.e if the generated
group is either the special unitary or the special orthogonal
group. To every gate I will assign its image under the adjoint
representation. The necessary condition for the universality is
that the only matrices that commute with all the adjoint
representation matrices are proportional to the identity. If in
addition there is an element in the considered group whose
Hilbert-Schmidt distance from the centre is smaller than
1/√2, then the set of gates is universal. Using these I
will present a simple algorithm that allows deciding the
universality of any set of d-dimensional gates in a finite number
of steps. Moreover, I will formulate the general classification
theorem. This is a joint work with Katarzyna Karnas.
Chair: Prof. UAM dr hab. Andrzej Grudka
Seminar language: English
/309/
Data: Środa 2017.03.22, 10:00
Prelegent: Mgr Przemysław Sadowski
Afiliacja: Instytut Informatyki Teoretycznej i Stosowanej PAN w
Gliwicach
Tytuł: Kwantowe wyszukiwanie z dodatkową wiedzą o sieci
Streszczenie: Prezentowana praca jest poświęcona analizie modelu
błądzenia kwantowego wzbogaconego o możliwość definiowania różnych
rodzai krawędzi. Poszczególne rodzaje krawędzi definiowane są
poprzez zróżnicowanie zmiany fazy następującej podczas przejścia
daną ścieżką. Prezentujemy metody pozwalające lokalnie badać
własności sieci oparte na rodzajach występujących krawędzi oraz
sterować zachowaniem błądzenia w zależności od tych własności. W
szczególności rozważamy problem przeszukiwania w przypadku gdy
rodzaj krawędzi określa czy dany kierunek może prowadzić do
szukanego wierzchołka.
Prowadzący: Dr hab. Paweł Kurzyński
Seminar language: Polish
/308/
Data: środa 2017.03.15, 12:00
Prelegent: Dr Mikołaj Pochylski
Afiliacja: Zakład Biofizyki Molekularnej, Wydział Fizyki, UAM
Tytuł: Historia postępu w badaniach zjawiska rozpraszania
Brillouina
Streszczenie: Przewidziane blisko 100 lat, temu zjawisko rozpraszania
Brillouina pozwoliło na połączenie dwóch wówczas niezależnych
gałęzi fizyki: termodynamikę i optykę. Od tego czasu,
systematyczny rozwój technik pomiarowych zamienił ciekawą
koncepcję fizyczną w pełni rozwiniętą metodę spektroskopową
wykorzystywaną w badaniach spontanicznych wzbudzeń akustycznych w
materii skondensowanej.
Podczas wystąpienia przedstawiona
zostanie droga jaką przebyła metoda spektroskopii Brillouina,
zaczynając od wyjaśnienia fizycznych podstaw zjawiska, które
doprowadziły do jego teoretycznego przewidzenia. Zaprezentowany
zostanie rozwój w konstrukcji wysoko-rozdzielczych spektrometrów
optycznych, począwszy od pierwszych układów użytych do
doświadczalnego potwierdzenia zjawiska rozpraszania Brillouina, aż
po współczesne instrumenty wykorzystywane w fizykochemicznych
badaniach materii skondensowanej. Omówiona zostanie również
najnowsza konstrukcja spektrometru brillouinowskiego, dzięki
której możliwy stał się szybki, bezkontaktowy i bezinwazyjny
pomiar właściwości mechanicznych materii miękkiej, znajdujący
zastosowanie w zagadnieniach biomedycznych.
Prowadzący: Prof. Maciej Krawczyk
Seminar language: Polish
/307/
Date: Friday 2017.03.10, 10.00
Speaker: Prof. Michael Farle
Affiliation: A Distinguished Lecturer of the IEEE Magnetics
(2017), University of Duisburg-Essen, Germany, and Immanuel Kant
Baltic Federal University, Russia
Title: Functionalized Hybrid Nanomagnets: New Materials for
Innovations in Energy Storage and Medical Theranostics
Abstract: Imagine a future in which food is used to activate
specific immune reactions in a human body based on an external
noninvasive magnetic stimulus. Dream of a material that stores and
releases energy reversibly by temperature changes between day and
night. These visions may be realized by using magnetic
nanoparticles that are functionalized to be biocompatible,
environmentally stable and recyclable, self-healing, and
low-cost.
In this presentation I will discuss the basic
concepts of magnetic nanomaterials and their magnetic properties
with a focus on how to tune specific parameters in a controlled
fashion to achieve the dreams of the future. I will highlight
state-of-the-art experimental technologies that allow us to
understand microscopic properties and interactions in relation to
electronic structure changes caused by changes in size, shape, and
composition of nanomaterials. Then I will discuss how this
understanding is used when nanomagnets are functionalized for
targeted drug delivery or composed to form macroscopic materials
for new energetic applications like magnetic refrigeration. I will
demonstrate that the seemingly complex behavior of hybrid
metal/metal, metal/oxide, or oxide/oxide interface materials can
be understood from the three fundamental interactions in
magnetism: magnetic exchange interaction due to orbital overlap,
spin-orbit interaction due to inner- and intra-atomic relativistic
corrections (e.g., crystal field effects) and the long-range
magnetic dipolar interaction. Several examples will be presented,
including the formation of above-room-temperature ferromagnetic
interface layers between low-temperature antiferromagnetic layers
and the evolution of lattices of magnetic textures (skyrmions) in
confined dimensions. The talk will end with an episode in the life
of an imaginary golf-playing couple in the year 2040 who use their
“Smart Magnet” (SMAG) phone to energize and heal their bodies on
the green.
Biography: Michael Farle received his Diploma in experimental physics, Doctorate, and Habilitation degrees from Freie Universität Berlin in 1984, 1989, and 1998, respectively. During this time he spent three and a half years as a senior researcher at Stanford University, California, and Université de Strasbourg, France. In 1999, he moved to Technische Universität Braunschweig, Germany, where he became a full professor. Since 2002, he has been working as a professor at the Universität Duisburg-Essen, Germany, where he has served as Vice-Rector for Research and Junior Scientific Staff. In 2016 he became, in addition, an adjunct professor at Immanuel Kant Baltic Federal University, Kaliningrad, Russia.
Prof. Farle has published over 220 technical articles in peer-reviewed journals, including book chapters and review articles, and has given more than 60 invited presentations. He coordinated two European Research Networks and served as the vice-spokesman of Collaborative Research Center: Magnetic Heterostructures (SFB 491). Since 2014 he is chairman of the Magnetism Section of the German Physical Society. For many years he has been active on the program committees of several international conferences on magnetism. He is a member of the IEEE Magnetics Society, the German Physical Society, and is a co-editor of Materials Research Letters and Journal of Magnetism and Magnetic Materials.
source: [IEEE Magnetics Society about the 2017 Distinguished Lecturer]
Chair: MK
Seminar language: English
/306/
Data: środa 2017.03.01, 12:00
Prelegenci: Mgr Filip Berski i Prof. UAM dr hab. Piotr Dybczyński
Afiliacja: Obserwatorium Astronomiczne, Wydział Fizyki, UAM
Tytuł: Bliskie przejścia gwiazd koło Słońca w świetle pierwszych
wyników misji Gaia
Streszczenie: Od roku 1950 kiedy to Jan H. Oort sformułował swoją
hipotezę o sferycznym rezerwuarze komet otaczającym Układ
Słoneczny trwają badania nad bliskimi przejściami gwiazdowymi.
Oort sugerował, że takie zbliżenia są jedynym źródłem komet
długookresowych (LPC's) – dziś wiemy, że działają również inne
mechanizmy. Jednak częstość występowania bliskich przejść
gwiazdowych jest wciąż tematem dyskusji. Wynika to między innymi z
faktu, że do niedawna badania gwiazd zbliżających się do Słońca w
głównej mierze opierały się na danych zgromadzonych przez sondę
Hipparcos w pierwszej połowie lat 90. ubiegłego wieku, na
podstawie których powstał katalog zawierający wszystkie parametry
astrometryczne dla około 120 000. We wrześniu ubiegłego roku
został opublikowany pierwszy katalog oparty o dane zgromadzone
przez sondę Gaia z pierwszych 14 miesięcy jej działania. Katalog
ten zawiera niezbędne informacje dla ponad dwóch milionów gwiazd.
Jednym z pierwszych wyników uzyskanych dzięki temu katalogowi jest
udokładnienie parametrów przejścia gwiazdy Gliese 710, która po
tej korekcie przejdzie nie 60 tys. AU od Słońca jak to wynikało z
wcześniejszych badań a tylko około 13 tys. AU. Tak bliskie
przejście gwiazdy spowoduje duże perturbacje w Obłoku Oort'a czego
skutkiem może być nawet dziesięć nowych komet rocznie pochodzących
z tej odległej części Układu Słonecznego.
Przewodnicząca seminarium: Prof. UAM dr hab. Agnieszka
Kryszczyńska
Seminar language: Polish
/305/
Date: Wednesday 2017.02.22, 12:00
Speakers: Dr Michał Oszmaniec
Affiliation: Acin's Group at the Institute of Photonic Sciences
(ICFO) in Barcelona
Title: Universal extensions of restricted classes of quantum
operations
Abstract: For numerous applications of quantum theory it is
desirable to be able to apply arbitrary unitary operations on a
given quantum system. However, in particular situations only a
subset of unitary operations is easily accessible. This provokes
the question of what additional unitary gates should be added to a
given gate set in order to attain physical universality, i.e., to
be able to perform arbitrary unitary transformation on the
relevant Hilbert space. In this work, we study this problem for
three paradigmatic cases of naturally occurring restricted gate
sets: (A) particle-number preserving bosonic linear optics, (B)
particle-number preserving fermionic linear optics, and (C)
general (not necessarily particle-number preserving) fermionic
linear optics. Tools from group theory and control theory allow to
classify, in each of these scenarios, what sets of gates are
generated, if an additional gate is added to the set of allowed
transformations. This solves the universality problem completely
for arbitrary number of particles and for arbitrary dimensions of
the single-particle Hilbert space.
After the presentation of these results, I will show they can be
useful in the context of quantum metrology [1] and for the model
of quantum computation based on fermionic linear optics [2,3].
This talk is based on a joint project with Zoltan Zimboras (Freie
Universitat Berlin).
[1] M. Oszmaniec, R. Augusiak, C. Gogolin, J. Kołodyński, A. Acín,
and M. Lewenstein, Phys. Rev. X 6, 041044 (2016)
[2] Sergey Bravyi, Phys. Rev. A 73, 042313 (2006)
[3] Fernando de Melo, Piotr Ćwikliński, Barbara M. Terhal, New J.
Phys. 15 013015 (2013)
Chair: Dr hab. Paweł Kurzyński
Seminar language: English
/304/
Data: piątek 2017.01.27, 12:00
Prelegenci: Dr Przemysław Bartczak i Mgr Grzegorz
Dudziński
Afiliacja: Obserwatorium Astronomiczne, Wydział Fizyki, UAM
Tytuł: Rekonstrukcja kształtów planetoid z obserwacji radarowych
Przewodnicząca seminarium: Prof. Agnieszka Kryszczyńska
Seminar language: Polish
/303/
Date: Wednesday 2017.01.25, 12:00
Speaker: Prof. Michał Banaszak
Affiliation: High Pressure Physics Division, Physics Faculty, AMU
Title: Artificial molecular machines revisited
Abstract: The development and fabrication of mechanical devices
powered by artificial molecular machines is one of the
contemporary goals of nanoscience. Before this goal can be
realized, however, we must learn how to control the
coupling/uncoupling to the environment of individual switchable
molecules, and also how to integrate these bistable molecules into
organized, hierarchical assemblies that can perform significant
work on their immediate environment at nano-, micro- and
macroscopic levels. In this lecture we review some ideas for which
the Nobel Prize in Chemistry was awarded in 2016.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/302/
Date: Wednesday 2017.01.18, 12:00
Speaker: Prof. Piotr Tomczak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Kosterlitz-Thouless transition in 1D Heisenberg
antiferromagnet: An evidence based on topological properties of
the ground state
Abstract: A Kosterlitz-Thouless phase transition in the ground
state of an antiferromagnetic spin-1/2 Heisenberg chain with
nearest and next-nearest neighbor interactions is re-investigated
from a new perspective: A mapping of the components of the scalar
product onto loops is found. One can classify these loops
according to whether any two of them can be transformed into each
other in a continuous way (i.e., whether they have the same
winding number). A finite size scaling of the fidelity
susceptibility and geometrical phase calculated in the ground
state of the considered system within each class of above
mentioned loops leads to the critical value of coupling constant
and critical exponents with high accuracy.
Chair: Prof. Michał Banaszak
Seminar language: Polish
/301/
Date: Friday 2017.01.13, 11:00
Speaker: Prof. Tadeusz Domański
Affiliation: Condensed Matter Theory Department, Marie
Curie-Sklodowska University, Lublin
Title: Majorana quasiparticles in nanoscopic superconductors
Abstract: Recently there has been enormous interest in studying
the Majorana fermions (identical with their own antiparticles)
that can emerge as the effective quasiparticles in topological
superconductors. They are appealing for the basic science and
their non-Abelian character makes them promising for a brand new
Majorana spintronics. So far the most convincing evidence for such
exotic Majorana quasiparticles has been provided by tunneling
measurements using, the Rashba chains brought in a contact with
the s-wave superconducting samples (such as Pb). Independent
experiments by groups in Delft, Princeton, Basel and Berlin have
clearly indicated enhancement of the zero-bias STM conductance.
Further efforts for detecting the Majorana fermions rely on novel
methods, e.g. selective equal-spin Andreev reflection (SESAR),
Josephson spectroscopy, fractional quantum interference etc. I
shall describe main theoretical concepts beyond the Majorana-type
quasiparticles, which can be regarded as mutations of the Shiba
states of spinfull impurities in bulk superconductors. Next, I
will illustrate non-local nature of such quasiparticles, discuss
their fractionality (in comparison to ordinary electrons) and
prove that they are not completely immune to disorder (despite a
wide-spread belief). I will also comment on novel projects,
related to localization of Majorana quasiparticles on interfaces
or quantum defects.
Chair: Prof. Ireneusz Weymann
Seminar language: English
/300/
Date: Wednesday 2017.01.11, 12:00
Speaker: Prof. Jan Martinek
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, Poznań
Title: Topological phase transitions and topological phases of
matter – Nobel in Physics 2016
Chair: Prof. Antoni Wójcik
Seminar language: English
/299/
Date: Wednesday 2017.01.04, 12:00
Speaker: Prof. Zbigniew Ficek
Title: Beating the limit of Quantum Fluctuations
Affiliation: National Centre for Applied Physics,
King Abdulaziz City for Science and Technology (KACST),
Riyadh, Saudi Arabia
Abstract:
All systems fluctuate and according to quantum physics fluctuations persist even if all sources of error have been eliminated. The fluctuations limit the sensitivity achieved by detectors for spectral resolution and hence they limit the accuracy to which measurements can be performed. Quantum physics imposes a limit on the fluctuations called the quantum limit of fluctuations. Fluctuations of all systems including light are subject to this limit, and it was long believed that this limit could not be suppressed. In the 1980s theoretical studies followed by experimental measurements showed that the quantum limit can be beaten using quantum technologies that employ quantum effects such as quantum interference, squeezing, and entanglement.
In this talk I will review the efforts done by researchers in the field of quantum optics to search for methods to reduce or even completely suppress the undesirable effects resulting from the presence of quantum fluctuations. The talk is based on the content of a book, Z. Ficek and R. Tanaś, Quantum-Limit Spectroscopy, published by Springer in November 2016.
Chair: Prof. Adam Miranowicz
Seminar language: English
/298/
Date: Wednesday 2016.12.21, 12:00
Speaker: Prof. R. Wojciechowski*, Dr hab. M. Wiesner#,
Prof. A. Lehmann-Szweykowska*, and Prof. Michał
Kurzyński*
Affiliation: *Solid State Theory Division and #Crystals
Physics Division, Faculty of Physics, AMU
Title: Spontaneous and strain-mediated commensurate-incommensurate
phase transformations in LiCsSO4 and similar materials
Chair: Prof. Maciej Krawczyk
Seminar language: English
/297/
Date: Wednesday 2016.12.14, 12:00
Speaker: Prof. Oksana Gorobets
Affiliation: National Technical University of Ukraine “KPI” Kiev, Ukraine
Title: Nonlinear solutions of the Landau-Lifshitz equations in
antiferromagnetic materials
Chair: Prof. Maciej Krawczyk
Seminar language: English
/296/
Date: Friday 2016.12.09, 11:30
Speaker: Prof. Teruo Ono
Affiliation: A Distinguished Lecturer of the IEEE Magnetics
(2016), Kyoto University, Japan
Title: Spin Dynamics in Inhomogeneously Magnetized Systems
Abstract: Worldwide efforts are underway to create revolutionary and energy-efficient data storage technology such as magnetic random-access memory (MRAM). An understanding of spin dynamics in inhomogeneously magnetized systems is indispensable for further development of nanoscale magnetic memory. This lecture provides a clear picture of inhomogeneously magnetized systems, such as magnetic nanowires with domain walls and disks with magnetic vortices, and presents not only technological developments and key achievements but also the unsolved puzzles and challenges that stimulate researchers in the field.
First, the basic concept of an inhomogeneously magnetized system is described by introducing a magnetic vortex structure in a magnetic disk. A magnetic domain wall in a magnetic nanowire is also provided as a typical example. The magnetic field-driven dynamics of these inhomogeneously magnetized systems are described to illustrate their uniqueness. Second, electric-current-induced dynamics of magnetic vortices and domain walls are described. One can flip the core magnetization in a magnetic vortex using electrical current excitation, and move a domain wall by current injection into a wire. The next part focuses on the applications of current-induced magnetization dynamics in devices. The basic operations of two kinds of magnetic memories—magnetic vortex core memory and magnetic domain wall memory—are demonstrated. The lecture describes not only the current understanding about inhomogeneously magnetized systems, but also unexpected features that have emerged. It concludes with prospects for future developments.
Biography:
Teruo Ono received the B.S., M.S., and D.Sc. degrees from Kyoto University in 1991, 1993, and 1996, respectively. After a one year stay as a postdoctoral associate at Kyoto University, he moved to Keio University where he became an assistant professor. In 2000, he moved to Osaka University where he became a lecturer and an associate professor. Since 2004, he has been working at Kyoto University, where he is now a professor. He has published over 280 technical articles in peer-reviewed journals, including book chapters and review articles, and has given more than 90 invited presentations at international conferences. He served as conference co-chair of the 8th International Symposium on Metallic Multilayers (MML) in 2013, and on the program committees of various international conferences on magnetism and spintronics. He is a member of the IEEE Magnetics Society and is an editor of the Japanese Journal of Applied Physics.
source: [www.ieeemagnetics.org]
Chair: Prof. Maciej Krawczyk
Seminar language: English
/295/
Date: Wednesday 2016.11.16 at 13:30
Speaker: Prof. Sylwester Porowski
Affiliation: Instytut Wysokich Ciśnień PAN w Warszawie
Title: Azotek galu GaN - od kryształów do struktur kwantowych
Abstract: W prognozach głównych trendów rozwoju technologicznego
i cywilizacyjnego w XXI wieku przewiduje się, że azotek galu
(GaN), który jest stosunkowo nowym półprzewodnikiem, może odegrać
rolę porównywalną z tą, jaką odegrał krzem w drugiej połowie XX
wieku i bez którego trudno by było wyobrazić sobie obecnie
funkcjonowanie świata. Nagroda Nobla z fizyki w 2014 r. dla I.
Akasaki, H. Amano i S. Nakamury za skonstruowanie z GaN wydajnej
diody emitującej światło niebieskie (blue LED) potwierdza trafność
tych trendów. Wynalazek Noblistów pozwolił na dramatyczne
zwiększenie efektywności zamiany energii elektrycznej na światło,
co według szacunków amerykańskiego Departamentu Energii już w 2030
doprowadzi do zmniejszenia zużycia energii na oświetlenie w USA
prawie o połowę. Na świecie badania azotku galu rozwijają się
niezwykle dynamicznie i wiadomo już, że rewolucja w oświetleniu
spowodowana wynalazkiem Noblistów jest dopiero początkiem
przyszłych zastosowań tego półprzewodnika. Dlaczego jednak sukces
tego półprzewodnika przyszedł tak późno? Które z jego własności o
tym zadecydowały? Czy jest podobny do innych półprzewodników
AIIIBV, czy też jest w nim jakaś tajemnica, która przez
ponad 40 lat była barierą w praktycznym jego wykorzystaniu? Jakie
to były bariery i jak zostały przełamane? W Polsce badania w tych
dziedzinach rozwijają się bardzo intensywnie. Badania naukowe w
zakresie fizyki i technologii tego stosunkowo nowego
półprzewodnika są już obecnie prowadzone w 11 instytucjach
naukowych. Powstały dwie firmy Ammono S. A. i TopGaN Sp. z o.o.
prowadzące produkcję doświadczalną monokrystalicznych podłoży GaN
oraz laserów niebieskich. Polska należy do elitarnej grupy krajów
posiadających kompletną technologię produkcji niebieskich laserów
(Japonia, Niemcy, USA, Polska). W prezentacji omówione zostaną
niektóre wyniki polskich badań w dziedzinie w dziedzinie GaN oraz
szanse na ich praktyczne wykorzystanie.
Chair: MK
Seminar language: Polish
/294/
Date: Wednesday 2016.11.09, 12:00
Speaker: Dr Michał Krupiński
Affiliation: The H. Niewodniczanski Institute of Nuclear Physics,
Polish Academy of Sciences, Department of Materials Science,
Kraków
Title: Large Area Antidot and Dot Arrays with Perpendicular
Magnetic Anisotropy
Abstract: Recently, there has been growing interest in the
fabrication, characterization, and modeling of patterned magnetic
thin films due to their potential applications in the field of
magnetic storage, sensors, radio frequency components, information
processing, and magnonic crystals. This specific interest is
primarily due to the possibility of controlling the magnetic
properties by introducing in ferromagnetic material artificial
defects such as antidots, dots or nonmagnetic inclusions arranged
in ordered or disordered arrays. In particular, the hysteresis
properties of such systems can be easily tailored by shape, size,
and distance between the nanostructures as well as by arrays order
and their symmetry. The talk will focus on the magnetic properties
and switching behavior of well-ordered magnetic antidot and dot
arrays consisting of Co/Pd thin films. The patterning effect as
well as the influence of period and size on domain shape and
domain wall behaviour will be discussed. Magnetic transition from
antidot to dot regime will be also analysed.
Chair: dr hab. Jarosław Kłos
Seminar language: English
/293/
Date: Tuesday 2016.11.08, 12:00
Speaker: Dr Ra’anan I. Tobey
Affiliation: Zernike Institute for Advanced Materials, University
of Groningen, Netherlands
Title: Transient Grating Spectroscopy in Magnetic Thin Films:
Magnetoelastic Transients, Spin Wave Generation and Interference,
and Driven Nonlinear Phenomena
Abstract: Control of material properties is one of the driving
forces in ultrafast optical sciences. The notion that light can
influence intrinsic material parameters is founded on a wide range
of experiments demonstrating optomagnetic control, light induced
superconductivity, and the photo induced insulator to metal
transition in a wide range of materials. A recent addition to the
tool chest of control methodologies is the excitation of acoustic
waves, and their affect on intrinsic materials properties;
particularly the material magnetization via magnetostrictive
effects. In this talk I will describe our recent efforts [1,2] to
optically generate in-plane magnetoelastic waves in the test
material nickel. Using a combination of the transient grating (TG)
and Faraday techniques, we probe the magnetic dynamics of the
intrinsically acoustic excitations. The dispersion characteristics
of our excitations can be uniquely identified as arising from
in-plane Rayleigh and longitudinal acoustic excitations while at
particular values of applied external magnetic field, the acoustic
excitation coherently couples to a k-vector tunable ferromagnetic
resonance in the film. I will balance the talk between discussion
of the experimental apparatus and its benefits as well as
discussing the array of elastically actuated FMR, dipole-exchange
spin waves, and nonlinearities that arise. I will also discuss
open questions and potential collaborative work.
[1] J. Janusonis et al., APL 106, 181601 (2015).
[2] J. Janusonis et al., arXiv:1601.04350 (2016).
Chair: dr hab. Jarosław Kłos
Seminar language: English
/292/
Date: Friday 2016.11.04, 12:00
Speaker: Mgr inż. Łukasz Pawela
Affiliation: Institute of Theoretical and Applied Informatics,
Polish Academy of Sciences
Title: Asymptotic distances of random quantum states and random
quantum channels
Abstract: Properties of random mixed states of dimension N
distributed uniformly with respect to the Hilbert-Schmidt measure
are investigated. We show that for large N, due to the
concentration of measure, the trace distance between two random
states tends to a fixed number ~D=1/4+1/π, which
yields the Helstrom bound on their distinguishability. To arrive
at this result we apply free random calculus and derive the
symmetrized Marchenko-Pastur distribution, which is shown to
describe numerical data for the model of coupled quantum kicked
tops. Asymptotic value for the root fidelity between two random
states, √F=3/4, can serve as a universal reference value
for further theoretical and experimental studies. Analogous
results for quantum relative entropy and Chernoff quantity provide
other bounds on the distinguishablity of both states in a multiple
measurement setup due to the quantum Sanov theorem. We study also
mean entropy of coherence of random pure and mixed states and
entanglement of a generic mixed state of a bi-partite system. For
quantum channels, we show that their level density is also
described by the Marchenko-Pastur distribution. This allows us to
deduce some properties of the diamond norm of large dimensional
quantum channels.
Chair: Prof. UAM dr hab. Andrzej Grudka
Seminar language: English
/291/
Date: Wednesday 2016.10.26, 12:00
Speaker: Dr hab. Katarzyna M. Rećko
Affiliation: Faculty of Physics, University of Białystok
Title: Magnetic structure and basic interactions of MFe4Al8
(M=Sc and U)
Abstract: Physics of transition metals and physics of f-electron
elements belong to permanently fascinating subject. The
experimental and theoretical research groups are interested in the
mechanisms of fundamental interactions between atoms, leading to
the formation of a specific crystal structures, the conditions for
the formation of magnetic moments in metals and basic interactions
between magnetic moments in the conditions of metallic bonds. The
importance of the symmetry as well as the nature of the magnetic
interactions between even distant partners are discussed and
illustrated by selected systems. The correlation between the
alloy’s composition and their degree of order are taken into
consideration. The aim of the research presented here was to
uncover the specific mechanisms leading to frequently noncolinear
and incommensurate magnetic ordering of the alloys based on metals
with the typical weakly localized magnetic moments, i.e. the
elements of so-called 3d block coupled through band electrons as
for example in light Actinides – 5f. During the search of the
mechanisms responsible for long-range magnetic ordering of
intermetallic systems based on simple p– and d–electron metals, in
which, after all there is no dominance of effects such as
magnetocrystalline anisotropy, the main attention was devoted to
the aspects of symmetry of periodic commensurate crystal
structures as well as commensurate and incommensurate magnetic
ones. For the sake of clarity, a brief overview of known
mechanisms of direct, indirect and super- exchange interactions of
the Fe atoms, which have in the neighborhood p, d or f–electrons
is given together with the general review of elementary sources of
anisotropy due to the components of the measured compounds. All of
the presented papers concern the results of experiments performed
with the use of non-polarized neutron beams in the scenario of
elastic and coherent scattering. Analysis of data collected for
high symmetry directions allow determination of the details of
magnetic interactions of exchange constants derived within the
Weiss' molecular field theory approximation of the crystal field
or in the tensor resulting from a search of the exchange constants
by Monte Carlo methods. Recent papers in this vein are trying to
adopt the simplest models, namely the crystal field model in the
conditions of the low recognition of the input anisotropy
parameters of the commensurate UFe4Al8 and the distribution
of magnetization in an incommensurate ScFe4Al8.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/290/
Date: Thursday 2016.10.20
Speaker: Doc. Jan Soubusta
Affiliation: Institute of Physics of Academy of Science of the
Czech Republic, Joint Laboratory of Optics of PU and IP AS CR,
Olomouc, Czech Republic
Title: Study of nonlinear magneto-optical effects
Abstract: Nonlinear crystals are typically used when interaction
of different colors of light is requested. In classical optics
these nonlinear phenomena are used for second-harmonic generation,
sum-frequency generation, optical parametric amplification or many
other effects. In quantum optics, dealing with optical interaction
on the level of individual photons, the most prominent process is
spontaneous parametric down-conversion (SPDC). Influence of
magnetic field on these nonlinear processes was not thoroughly
tested yet. This topic deserves intensive study both from
theoretical and experimental point of view, because the magnetic
field can decrease the symmetry of the nonlinear crystal and so it
may allow to use new types of phase-matching conditions. We
started to test the SPDC process in BBO crystals. BBO is a
trigonal (3m) negative uniaxial material. Nonlinear magneto-optic
tensor of this material is not known and we can hardly predict it.
According to our first theoretical derivation the efficiency of
the nonlinear processes has to oscillate when rotating the
magnetic-field orientation.
Chair: Prof. Adam Miranowicz
Seminar language: English
/289/
Date: Thursday 2016.10.20
Speaker: Dr Antonín Černoch
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Construction of highly versatile four-photon source
Abstract: We have constructed a four-photon source for quantum
information processing experiments. In comparison to others
implementation our source generates two different photon pairs -
entangled, separable or completely mixed in polarisation.
Chair: Prof. Adam Miranowicz
Seminar language: English
/288/
Date: Thursday 2016.10.20
Speaker: Dr Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Experimental measurement of the collectibility of two-qubit
states
Abstract: The talk will discuss the measurement of collectibility
entanglement witness on several two-qubit states. I will present
our experimental setup, the measurement procedure and then compare
obtained data with theoretical prediction.
Chair: Prof. Adam Miranowicz
Seminar language: English
/287/
Date: Wednesday 2016.10.19, 12:00
Speakers: Prof. Michał Kurzyński & Dr Przemysław
Chełminiak
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: The very laws of dynamics do not determine organization of
physical systems. What is information?
Abstract: Self-organization in thermodynamics and quantum as well
as classical mechanics is the result of spontaneous symmetry
(ergodicity) breaking, i.e., a random choice in the past. Under
specially tuned conditions, when the system reaches a critical
dynamics, self-organization becomes hierarchical. The very
self-organized criticality is possible only in open systems. We
tested the hypothesis that the conformational transition networks
of the natively disordered proteins have a self-organized critical
structure. Using a formalism of the generalized fluctuation
theorem, we shown that the biological molecular machines with such
dynamics transduce not only energy but also organization, defined
by the suitable physical variable. Like work and heat are changes
in energy, information and entropy production/reduction are
changes in this variable.
Chair: Prof. Maciej Krawczyk
Seminar language: English
/286/
Date: Friday 2016.10.14, 12:00
Speaker: Dr hab. Jarosław S. Kłos
Affiliation: Zakład Fizyki Komputerowej, WF UAM
Title: Symulacje komputerowe dendrymerów neutralnych i
naładowanych
Abstract: Dendrymery są polimerami zbudowanymi z łańcuchów
liniowych (spejserów) połączonych sukcesywnie, generacja po
generacji, w regularną, hierarchiczną strukturę drzewiastą. W
zależności od panujących w roztworze warunków makrocząsteczki te
są neutralne bądź uzyskują ładunek elektryczny. Ze względu na
specyficzną, rozgałęzioną architekturę szkieletu molekularnego
dendrymerów, oddziaływania objętości wykluczonej i
elektrostatyczne mają duży wpływ na ich własności konformacyjne.
Na seminarium zostaną przedstawione wyniki badań nad pojedynczymi,
neutralnymi i naładowanymi dendrymerami z giętkimi spejserami,
które przeprowadzono za pomocą gruboziarnistych symulacji
komputerowych metodą Monte Carlo. Symulacje te pozwoliły na
analizę rozmiaru i struktury wewnętrznej dendrymerów w szerokim
zakresie liczby generacji i długości spejserów. Dla dendrymerów
obdarzonych ładunkiem wykonane obliczenia umożliwiły obserwację i
jakościowy opis efektu ich „puchnięcia” w warunkach neutralnego i
niskiego pH.
Chair: Prof. Maciej Krawczyk
Seminar language: Polish
/285/
Date: Friday 2016.10.14, 10:00
Speaker: Dr hab. Arkadiusz Józefczak
Affiliation: Zakład Akustyki Molekularnej, Instytut Akustyki, WF
UAM
Title: Magnetic nanoparticles for enhancing the effectiveness of
ultrasonic hyperthermia
Abstract: Ultrasonic hyperthermia is a method of cancer treatment
in which tumors are exposed to an elevated cytotoxic temperature
using ultrasound (US). In conventional ultrasonic hyperthermia,
the ultrasound-induced heating in the tumor is achieved through
the absorption of wave energy. However, to obtain appropriate
temperature in reasonable time, high US intensities, which can
have a negative impact on healthy tissues, are required. The
effectiveness of US for medical purposes can be significantly
improved by using the so-called sonosensitizers, which can enhance
the thermal effect of US on the tissue by increasing US
absorption. One possible candidate for such sonosensitizers are
magnetic nanoparticles with mean sizes of 10-300 nm, which can be
efficiently heated because of additional attenuation and
scattering of US. Additionally, magnetic nanoparticles are able to
produce heat in the alternating magnetic field (magnetic
hyperthermia). The synergetic application of ultrasonic and
magnetic hyperthermia can lead to a promising treatment modality.
[A. Józefczak et al., App. Phys. Lett. 108, 263701 (2016)].
Chair: Prof. Maciej Krawczyk
Seminar language: English
/284/
Date: Wednesday 2016.10.12, 12:00
Speaker: Dr hab. inż. Bartłomiej Salski
Affiliation: Instytut Radioelektroniki i Technik Multimedialnych,
Politechnika Warszawska
Title: Novel understanding of resonant modes in YIG microwave
filters – experiments and electrodynamic study
Abstract: Numerical solutions of coupled Maxwell and
Landau-Lifshitz-Gilbert equations for a magnetized yttrium iron
garnet (YIG) sphere acting as a one-stage filter will be
discussed. The filter will be analysed using finite-difference
time-domain technique. Contrary to the state of the art, it will
be shown that the maximum electromagnetic power transmission
through the YIG filter occurs at the frequency of the magnetic
plasmon resonance with the effective permeability of the
gyromagnetic medium , and not at a ferromagnetic resonance
frequency. Such a new understanding of the YIG filter operation,
makes it one of the most commonly used single-negative plasmonic
metamaterials. The frequency of maximum transmission is also found
to weakly depend on the size of the YIG sphere. An analytic
electromagnetic analysis of resonances in a YIG sphere is
performed for circularly polarized electromagnetic fields.
Chair: Prof. Maciej Krawczyk
/283/
Date: Friday 2016.10.07, 12:00
Speaker: Dr hab. Krzysztof Gibasiewicz
Affiliation: Molecular Biophysics Division, Physics Faculty, AMU
Title: Energy and electron transfer in photosynthetic proteins -
fundamental and applied studies
Abstract: During the lecture I will briefly present the results of
my and my group’s studies being conducted within the last six
years. Most of them comes from the fundamental experimental
studies performed using the optical spectroscopic techniques on
photosynthetic proteins isolated from bacteria, algae, and plants.
These studies contributed, among others to understanding the role
of the protein dynamics in intraprotein electron transport. I will
also present our attempts to use the photosynthetic proteins in
solar cells.
Chair: Prof. Maciej Krawczyk
/282/
Date: Friday 2016.10.07, 10:00
Speaker: Dr hab. Paweł Kurzyński
Affiliation: Quantum Electronics Division, Faculty of Physics,
Adam Mickiewicz University and Centre for Quantum Technologies,
National University of Singapore
Title: Indistinguishability, strong correlations and their
dynamics in the quantum world
Abstract: Quantum particles exhibit peculiar correlations that
cannot be described by classical theories. These correlations are
responsible for various physical phenomena and they lie at the
heart of modern information theory. Additional complex features of
quantum correlations are manifested when the underlying particles
are fundamentally indistinguishable and when their dynamics occurs
in interacting and open systems. In this talk I will present my
recent results on how to describe, detect and model the evolution
of quantum correlations in various scenarios. I will also discuss
my future research directions related to this topic.
Chair: Prof. Maciej Krawczyk
/281/
Date: Wednesday 2016.10.05, 10:00
Speaker: M.Sc. Justyna Łodyga
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Measure-independent conditional uncertainty principle
Abstract: The uncertainty principle, which states that certain
sets of quantum-mechanical measurements have a minimal joint
uncertainty, has many applications in quantum cryptography. But in
such applications, it is important to consider the effect of a
(sometimes adversarially controlled) memory that can be correlated
with the system being measured. The information retained by such a
memory can in fact diminish the uncertainty of measurements.
Recently, different uncertainty relations in the presence of
memory were formulated in terms of the von Neumann conditional
entropy. However, the entropy is not the only measure that can be
used to quantify conditional uncertainty. Here, we develop a
general operational framework that formalizes the concept of
conditional uncertainty in a measure-independent form. Our
formalism is built around a mathematical relation that we call
conditional majorization. We define and characterize conditional
majorization and demonstrate the use of this framework by deriving
measure-independent conditional uncertainty relation in a
tripartite scenario. In particular, we provide a state-independent
lower bound on the minimal joint uncertainty that two remote
parties (Bob and Eve) have about the outcome of a given pair of
measurements performed by a third remote party (Alice),
conditioned on arbitrary measurements that Bob and Eve make on
their own systems.
Chair: Prof. Maciej Krawczyk
/280/
Date: Wednesday 2016.06.29, 12:00
Speaker: Prof. Richard J. Spontak
Affiliation: Department of Chemical & Biomolecular Engineering,
and Materials Science & Engineering, North Carolina State
University, Raleigh, U.S.A.
Title: The Dawning of a New Age for Thermoplastic Elastomers as
Functional Materials
Abstract: With recent advances made in the design and development
of multifunctional polymeric materials, elastomers derived from
triblock copolymers are in a good position to meet contemporary
materials challenges and explore new technological opportunities.
In this spirit, we consider the versatility of thermoplastic
elastomer (TPE) systems, which provide an attractive alternative
to chemically cross-linked materials because of their ability to
microphase-separate and form nanostructures connected by a
physically cross-linked network capable of withstanding
substantial deformation. We first consider the stimuli
responsiveness of triblock copolymers in the presence of
midblock-selective additives. Upon incorporation of a
midblock-selective oligomer, the molecular network formed by such
copolymers can be tunably swollen to yield highly elastic soft
systems, which exhibit composition-tunable mechanical properties
(including time-composition rheological equivalence), as well as
remarkable electromechanical properties. The morphological
features and mechanical properties of swollen TPE gel systems
generated from commercial and model styrenic TPEs will be
surveyed. These materials, subjected to electrical stimulation as
electroelastomers (i.e., dielectric elastomers) between compliant
electrodes, are shown to achieve actuation strains greater than
300% and electromechanical coupling efficiencies in excess of
90%. The electrostatic mechanism by which electroactuation
proceeds, as well as comparisons with other materials, will be
discussed. Unlike conventional dielectric elastomers composed of
chemically cross-linked elastomers, these copolymer systems are
easily processable and broadly tunable in terms of composition,
concentration and molecular weight, and they exhibit little cyclic
hysteresis. In the case of acrylic TPEs, electroactuation occurs
without the need for mechanical prestrain (often required to thin
specimens so that lower voltages can be used to achieve high
fields). These same triblock copolymers can be designed in
conjunction with liquid metals to yield ultrastretchable/flexible
electronic wires and antennae capable of remaining conductive
beyond 1000% strain, as well as with phase-change additives to
impart high-fixity/recovery shape memory. Incorporation of a
charged midblock permits addition of polar additives that can
further extend the scientific and technological diversity of TPEs.
Development of stimuli-responsive, hyperelastic and
shape-recovering polymeric materials, such as those to be
presented here, is critical for emerging applications such as
(micro)robotics, microfluidics and various biomedical devices.
Chair: Prof. Michał Banaszak
/279/
Date: Wednesday 2016.06.15, 12:00
Speaker: Prof. Ireneusz Weymann
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Andreev transport in hybrid quantum dots
Abstract: We will discuss the transport properties of quantum
dots coupled to superconducting and normal electrodes, focusing on
the transport regime where the current flows due to Andreev
reflection. In the case of weak coupling between the leads and the
dot, we show that Andreev current exhibits a nontrivial dependence
on the bias and gate voltages, which is also reflected in
magnetoresistive properties of the device. Moreover, we predict a
zero-bias anomaly of the Andreev differential conductance in the
parallel configuration of leads’ magnetizations, which is
associated with a nonequilibrium spin accumulation in the dot
triggered by Andreev processes. On the other hand, in the case of
strong coupling between the leads and the dot, we study the
influence of electron pairing on the Kondo state and show that the
emerging Kondo resonance can be significantly enhanced by
increasing the coupling to superconducting lead.
Chair: Prof. Adam Miranowicz
/278/
Date: Wednesday 2016.06.08, 12:00
Speaker: Prof. Marek Cinal
Affiliation: Institute of Physical Chemistry, Polish Academy of
Science, Warsaw
Title: Magnetic damping in metallic layered systems
Abstract: Dynamic magnetic phenomena, such as magnetization
switching by spin transfer torque and the current-induced motion
of domain walls, are strongly affected by spin relaxation. The
Landau-Lifshitz-Gilbert equation which describes magnetization
dynamics and is used as the basis for micromagnetic simulations,
accounts for spin relaxation by the inclusion of the
phenomenological damping term. The microscopic origin of the
Gilbert damping is the spin-orbit interaction which also plays the
key role in other effects of high relevance to spintronic
applications. The talk will present quantum mechanical
calculations of the Gilbert damping constant in magnetic layered
systems (ferromagnetic films, ferromagnet/nonmagnet bi-, tri-, and
multilayers built of transition metals) within the
torque-correlation model. It will be reported how the damping
constant depends on the type of nonmagnetic layers and the
geometric dimensions of the considered structures. The origin of
such dependences, including nonlocal damping in magnetic
trilayers, will be analyzed using the spatial decomposition of the
damping constant. In particular, the conditions for the
enhancement of the Gilbert damping will be discussed.
Chair: Prof. Maciej Krawczyk
/277/
Date: Monday 2016.06.06, 12:00
Speaker: Dr Felix Pollock
Affiliation: School of Physics & Astronomy, Monash University,
Australia
Title: How often does nature forget? The characterisation and
statistics of non-Markovian quantum processes
Abstract: In all but the most trivial open quantum process, some
amount information about a system's state will be `remembered' by
its environment, influencing the system's future evolution.
However, in practice, the assumption of environmental
`forgetfulness' or Markovianity is almost always made. This is
partly for practical reasons - until now there has been no unified
framework to describe the most general non-Markovian quantum
dynamics - but also remarkably, because the Markovian assumption
appears to be valid in many cases. I will present a new scheme for
operationally characterising non-Markovian quantum processes,
which both gives a theoretical understanding of such processes and
provides a recipe for reconstructing them experimentally.
Moreover, this scheme yields a natural measure on the space of of
all processes, which I will use to ask the question: how Markovian
is nature on average?
Chair: Prof. Adam Miranowicz
/276/
Date: Wednesday 2016.05.25, 12:00
Speaker: M.Sc. Marcin Jarzyna
Affiliation: Faculty of Physics, University of Warsaw
Title: Superadditivity in classical communication from a quantum
parameter estimation perspective
Abstract: We point out a contrasting role the entanglement plays
in communication and estimation scenarios. In the case of
communication it brings benefits both at the detection and input
stages, the facts known as output and input super-additvity
respectively. On the other hand, in estimation it is only the
entanglement of the input probes that enables performance
enhancement and we do not observe output super-additivity. We
identify a regime where a connection between concepts crucial to
the two fields is demonstrated. This allows us to shed new light
on the problem of super-additivity in communication.
Chair: Prof. Adam Miranowicz
/275/
Date: Tuesday 2016.05.17, 12:00
Speaker: Prof. Keith E. Gubbins
Affiliation: Department of Chemical |
Biomolecular Engineering,
North Carolina State University, Raleigh, U.S.A.
Title: Confinement-induced high pressure phases in nanopores: Can
the pressure be in the megabar range?
Abstract: [PDF] There is an abundance of anecdotal
evidence that nanophases adsorbed within nanoporous materials can
exhibit high pressures as a result of the confinement [1,2]. For
example, phase changes and chemical reactions that only occur at
high pressures in the bulk phase occur in the confined phase at
bulk phase pressures that are orders of magnitude lower. The
pressure in the pore is a second order tensor, and for simple pore
geometries has both a normal pressure component (normal to the
walls) and one or more tangential components (parallel to the
walls). For simple fluids in pores that are up to a few nanometers
in width, molecular simulations show that both the normal and
tangential pressures can be locally very high (thousands or tens
of thousands of bars) in the pore, even though the bulk phase in
equilibrium with the pore is at a pressure of one bar or less. The
cause of these high in-pore pressures will be discussed, and where
possible comparison with experimental results will be made [3].
When the molecules in the confined nanophase react with each other
chemically it may be possible to achieve even higher tangential
pressures, in the megabar range. Evidence for this is provided by
recent experiments on sulfur (an insulator at ambient conditions)
in narrow single-walled carbon nanotubes, carried out by Kaneko
and coworkers [4]. They find that the sulfur atoms within the pore
covalently bond to form a one-dimensional phase that is metallic.
In the bulk phase sulfur forms a metallic phase only at pressures
above 95 GPa. In our recent molecular dynamics simulations of
this system we find that the sulfur atoms are covalently bonded in
the pore and that they experience tangential pressures in excess
of 100 GPa as a result of the strong
confinement [5].
[1] Yun Long, Jeremy C. Palmer, Benoit Coasne, Małgorzata Śliwińska-Bartkowiak and Keith E. Gubbins, “Pressure enhancement in carbon nanopores: A major confinement effect”, Physical Chemistry Chemical Physics, 13, 17163-17170 (2011).
[2] Yun Long, Jeremy C. Palmer, Benoit Coasne, Małgorzata Śliwińska-Bartkowiak, George Jackson, Erich A. Müller and Keith E. Gubbins, “On the Molecular Origin of High Pressure Effects in Nanoconfinement: Effects of Surface Chemistry and Roughness”, Journal of Chemical Physics, 139, 144701 (2013).
[3] M. Śliwińska-Bartkowiak,H. Drozdowski, M. Kempinski, M. Jazdzewska, Y. Long, J.C. Palmer and K.E. Gubbins, „Structural Analysis of the Behavior of Water Adsorbed in Activated Carbon Fibers”, Physical Chemistry Chemical Physics, DOI: 10.1039/C2CP22111J (2012).
[4] Y. Fujimori, A. Morelos-Gómez, Z. Zhu, et al., “Conducting Linear Chains of Sulphur Inside Carbon Nanotubes”, Nature Comm., 4, DOI 10.1038/ncomms3162 (2013).
[5] K.E. Gubbins, C.A Addington and J.M. Mansell, to be
published.
Chair: Prof. Małgorzata Śliwińska-Bartkowiak
/274/
Date: Thursday 2016.05.12, 12:00
Speaker: Dr Maria Rosário Correia
Affiliation: Auxiliary Professor of Physics Department of
University of Aveiro, Researcher at I3N Associated
Laboratory-Aveiro, Departmental coordinator of Erasmus+ and Campus
Europae
Title: Raman Spectroscopy in the study of structural and optical
properties of different semiconductor nanostructures
Abstract: For desired applications, a deep knowledge of the
materials optical properties should be thoroughly investigated to
improve their efficiency and device development. The Raman
spectroscopy has been proved to be a powerful nondestructive
technique that enables the investigation of the structural,
electronic and optical properties of semiconductors
nanostructures. In this talk an overview of the fundamental
theoretical aspects of Raman scattering in will be given. The
potentialities of the technique on the characterization of
different semiconductor structures, will discussed based on cases
study. The effect of the strain and compositional effects on the
optical phonons of semiconductors based alloys, doping effects on
the polar optical phonons, resonant effects, and confined effects
in nanostructures are highlighted.
Chair: Prof. Krzysztof Grygiel
/273/
Date: Wednesday 2016.05.11, 12:00
Speaker: Prof. Marcus Münzenberg
Affiliation: Department of Physics, Ernst-Moritz-Arndt-University,
Greifswald, Germany
Title: Ultrafast dynamics of spins and spin currents: magnetic
storage and spintronic THz emitter
Abstract: [PDF] Magnetization manipulation is an
indispensable tool for both basic and applied research. I will
discuss some of the knobs to tune dynamics at ultrafast time
scales. The dynamics of the response depends on the energy
transfer from the laser excited electrons to the spins within the
first femtoseconds. This determines the speed of the ultrafast
magnetization: if the electrons are driven to a strong excitation
density, a second slower process is found. This slowdown is a
signature of the intrinsic ferromagnetic electron correlations in
a ferromagnet. One possibility of control is to shape the
properties of the electronic system. A special material of
interest for magnetic storage development is FePt. This
material allows an interesting modification of its density of
states: Pt alloying increases the magnetic anisotropy and reduces
the number of states at the Fermi level making it “more noble”.
Consequently, the electron temperature shoots to higher values
above the Curie temperature, a precondition for all-optical
writing [1,2]. On the other side due to the non-equilibrium
electron distribution, also ultrafast currents are generated and
contribute to the laser driven spin dynamics. Similarly, to
shaping the density of states in the first example, adjacent
layers of a noble metals like Pt, Au or transition metals like W,
Ta, Ru can shape the THz spin currents and convert ultrafast
laser-driven spin currents via the ultrafast spin-Hall effect into
a charge current burst. This opens a way towards novel THz
spintronic devices: optimizing thicknesses and layers, we can
realize efficient metallic THz spintronic emitters of
ultra-broadband terahertz radiation competing with state-of-art
photo-conductive switches THz emitters used for airport security
[3,4].
[1] J. Mendil, P. C. Nieves, O. Chubykalo-Fesenko, J. Walowski, M.
Münzenberg, T. Santos, S. Pisana, Sci. Rep. 4, 3980 (2014).
[2] U. Atxitia, O. Chubykalo-Fesenko, J. Walowski, A. Mann, and M.
Münzenberg, Phys. Rev. B 81, 174401 (2010).
[3] T. Kampfrath, M. Battiato, P. Maldonado, G. Eilers, J.
Nötzold, S. Mährlein, V. Zbarskyy, F. Freimuth, Y. Mokrousov, S.
Blügel, M. Wolf, I. Radu, P. M. Oppeneer, M. Münzenberg, Nature
Nanotech. 8, 256 (2013).
[4] T. Seifert, et al. arXiv:1510.03729
Chair: dr hab. Jarosław W. Kłos
/272/
Date: Wednesday 2016.05.04, 12:00
Speaker: Dr Michał Mruczkiewicz
Affiliation: Institute of Electrical Engineering, Slovak Academy
of Sciences, Dubravska cesta 9, 841 04 Bratislava, Slovakia
Title: Particular Properties of Spin Waves in Magnonic Crystals
Abstract: In the presentation I will show the results of
investigation on spin waves in periodic ferromagnetic structures
(magnonic crystals). The patterning at nanoscale permits to alter
the propagation of spin waves and modify their properties. The
focus of study is put on the following topics related to spin
waves properties: i) standing spin wave formation in magnonic
crystals ii) metamaterial properties for electromagnetic waves
propagating through magnonic crystal, iii) nonreciprocal
dispersion of spin waves and iv) collective dynamical skyrmion
excitations in the arrays of magnetic dots.
Chair: Prof. Maciej Krawczyk
/271/
Date: Wednesday 2016.04.20, 10:00
Speaker: Prof. Antoni Wójcik
Affiliation:
Zakład Elektroniki Kwantowej, Wydział Fizyki UAM
Title: Klasyczne splątanie czyli poplątanie pojęć
Abstract: Seminarium będzie kontynuacją zeszłorocznego seminarium
profesora Ryszarda Tanasia, na którym zaprezentowane zostały
wyniki dotyczące tzw. klasycznego splątania. Chciałbym przedstawić
ujednolicony i uproszczony model kilku różnych eksperymentów
(Phys. Rev. Lett. 88 (2002) 097902, Sci.Rep. 5 (2015) 9175, arxiv:
1406.3338, arxiv: 1511.02265, arxiv: 1511.08144), których wyniki
autorzy interpretują w kategoriach nieklasycznych korelacji
klasycznych obiektów. Prosty model pozwala na krytyczne
odniesienie się do takich interpretacji i pozwala lepiej zrozumieć
sens mierzonych parametrów.
Chair: Prof. Adam Miranowicz
/270/
Date: Monday 2016.04.18, 12:00
Speaker: Dr Maciej Bilicki
Affiliation: Sterrewacht Leiden, Universiteit Leiden, Netherlands
Title: Observational cosmology with the largest surveys of
galaxies
Abstract: One of the pillars of the standard cosmological model is
the observed distribution of galaxies on the largest scales, from
our cosmic neighbourhood to the farthest possible distances. I
will shortly describe how our knowledge of this distribution is
being gathered thanks to galaxy surveys, with a short historical
summary as well as the current status and future prospects. I will
also mention examples of cosmological information that can be
derived from such data and finally I will present my own and my
collaborators' work on such surveys, with an emphasis on data sets
covering the full extragalactic sky.
Chair: Dr Agata Karska
/269/
Date: Wednesday 2016.04.13, 12:00
Speaker: Prof. Tomasz Stobiecki
Affiliation: Katedra Elektroniki, Akademia Górniczo-Hutnicza w
Krakowie
Title: Nanourządzenia elektroniki spinowej: magnetyczne złącza
tunelowe i spin-torque oscylatory
(przegląd badań prowadzonych
na AGH)
Abstract: [PDF] W referacie omówię wyniki badań
prowadzonych w Katedrze Elektroniki AGH nad magnetycznymi złączami
tunelowymi z anizotropią magnetyczną w płaszczyźnie i prostopadłą,
zwracając szczególną uwagę na prąd krytyczny potrzebny do
przełączenia magnetyzacji i stabilność termiczną złącza. Na
przykładzie magnetorezystancyjnych nanoelementów (AMR, GMR i TMR),
działających w oparciu o efekt diody spinowej przedyskutuję
wzbudzenia jednorodnych modów FMR i fal spinowych.
Chair: Prof. Maciej Krawczyk
/268/
Date: Wednesday 2016.04.6, 12:00
Speaker: Prof. Andrzej Wawro
Affiliation: Institute of Physics of the Polish Academy of
Sciences, Warsaw
Title: Cienkowarstwowe nanokropki magnetyczne indukowane
strukturyzowanym podłożem
Abstract: [PDF] Wykorzystując samoorganizujący się
wzrost wysp Au o rozmiarach kilkudziesięciu nanometrów na
powierzchni warstwy Mo [1] oraz silną zależność anizotropii
magnetycznej ultracienkiej warstwy Co od rodzaju bufora, na którym
jest ona osadzana, wytworzono w systemie MBE (molecular beam
epitaxy) układ epitaksjalnych kropek magnetycznych [2, 3]. Kropki
stanowi ta część warstwy Co, która jest osadzona na powierzchni
wysp Au. Są one otoczone matrycą – warstwą Co osadzoną
bezpośrednio na powierzchni Mo, pomiędzy wyspami Au. W zależności
od grubości warstwy Co kropki i matryca charakteryzują się różnymi
wzajemnymi kierunkami namagnesowania. Szczególna uwaga poświęcona
jest konfiguracji, w której kropki są namagnesowane prostopadle do
płaszczyzny warstwy, a namagnesowanie matrycy leży w jej
płaszczyźnie. Stan remanencyjny układu oraz procesy
przemagnesowania kropek badane są przy pomocy techniki
magnetooptycznej (PMOKE) oraz mikroskopii sił magnetycznych (MFM).
Magnetyczny jednodomenowy charakter w dużym zakresie rozmiarów
kropek wynika z wysokiej jakości ich struktury krystalicznej.
Skorelowano wielkość pola przełączania magnetycznego kropek z ich
rozmiarami. Przeprowadzono symulacje mikromagnetyczne ilustrujące
procesy przemagnesowania kropek oraz profile namagnesowania [4].
Symulacje te wykonano dla rozmiarów i kształtów kropek
obserwowanych w eksperymencie. Poddano również analizie wpływ
wewnętrznej struktury kropek typu core/edge. Zaproponowano diagram
fazowy stanów magnetycznych i mechanizmów przemagnesowania kropek
w funkcji parametrów opisujących ich strukturę.
[1] A. Wawro et al., Nanotechnology 21 (2010) 335606.
[2] A. Wawro et al., Europhys. Lett. 89 (2010) 37003.
[3] A. Wawro et al., Phys. Rev. B 83 (2011) 092405.
[4] E. Milińska and A. Wawro, J. Appl. Phys. 116 (2014) 193905.
Chair: Prof. Maciej Krawczyk
/267/
Date: Wednesday 2016.03.23, 12:00
Speaker: Prof. Igor Lyubchanskii
Affiliation: Donetsk Physical and Technical Institute of the
National Academy of Sciences of Ukraine and Department of Physics
and Technology, Donetsk National University
Title: Cascading processes in the nonlinear diffraction of light
by standing acoustic waves
Abstract: The contribution of two types of cascading process to
the nonlinear optical diffraction of electromagnetic waves from a
standing acoustic wave in a GaAs crystal is theoretically studied.
The first type of cascading process results from second-harmonic
generation followed by linear acousto-optical diffraction, while
the second type involves linear acousto-optical diffraction from
the standing acoustic wave and subsequent sum-frequency
generation. In contrast to the third, direct, nonlinear
acousto-optical diffraction process we previously investigated,
the photoelastic interaction between electromagnetic and acoustic
waves is here linear. We establish the rules governing the
cascading processes and show that in most cases the output signal
simultaneously results from two or even three of the possible
nonlinear diffraction mechanisms. However, we demonstrate that a
careful choice of the incidence angles of the incoming
electromagnetic waves, of the polarization combinations of the
incoming and diffracted waves, and of the type of acoustic wave
(longitudinal or transverse) makes it always possible to
distinguish between the direct and either of the two cascading
processes.
Chair: Prof. Maciej Krawczyk
/266/
Date: Wednesday 2016.03.9, 12:00
Speaker: Prof. Joanna Trylska
Affiliation: Centre of New Technologies, University of Warsaw
(Centrum Nowych Technologii Uniwersytetu Warszawskiego)
Title: Molecular dynamics simulations of ribosomal RNA
Abstract: RNA has a complicated tertiary architecture and its
internal dynamics is often related to function. To investigate the
flexibility of RNA molecules we apply molecular dynamics
simulations using different approximations; from all-atom
representation in explicit solvent to simplified coarse-grained
models. I will present examples of applications of molecular
dynamics simulations to ribosomal RNA and experiments to determine
thermodynamics of various ribosomal RNA fragments.
Chair: Prof. Michał Banaszak
/265/
Date: Thursday 2016.03.3, 16:00
Venue: Seminar room in Nano-Bio-Med Centre
Speaker: Prof. Kwong-Yu Chan
Affiliation: Department of Chemistry, The University of Hong Kong,
Pokfulam Road, Hong Kong
Title: Polyelectrolyte Threaded in Metal-Organic Framework: A
Lattice Boltzmann Material?
Abstract: A new concept of structuring fixed charges in the
nanoscale for optimum ion exchange performance is introduced.
Crystalline porous charge exchange materials such as zeolites are
inflexible and are restricted to cation exchange. Polymer resins
have irregular porous structures. Fixed charges hidden by
hydrophobic forces are exposed only after swelling in aqueous
immersion. Threading polyelectrolyte chains into metal organic
frameworks (MOF) form a superior ion exchange material that
possesses advantages of both ceramic and polymeric domains. We
report two new composites of polyelectrolytes synthesized within a
MOF structure [1, 2].
Cation exchange function is provided by sodium poly(4-styrene
sulfonate) threaded in MIL-101 denoted as NaPSS MIL-101.[1] It is
synthesized directly with polymerization in situ of the MOF, as
shown in Figure 1. The NaPSS MIL-101 polyelectrolyte threaded in
MOF has high surface area of 1850 m2/g and a large specific volume
0.85 mL/g. Figure 2(a) compares the ion adsorption kinetics to
commercial ion-exchange resin IR-120. Excellent selectivity based
on charge is demonstrated when NaPSS MIL-101 is immersed into a
solution of two organic dyes, as shown in Figure 2(b). The anionic
Acid Blue 9 is excluded though it has significant van der Waals
affinity to high surface porous materials.Another example of
polyelectrolyte synthesized in MOF is demonstrated by anionic
polyvinyl benzyl trimethylammonium hydroxide (PVBTAH) threaded in
ZIF-8 (PVBTAH ZIF-8), with structure shown in Fig. 3 [2].
The high porosity, high surface area, uniform and ordered
structure of metal organic frameworks provide fast reversible ion
transport in a rigid nanoporous structure. On the other hand
polyelectrolyte chains have their charges well separated and
organized by the MOF framework, with reversible and local
flexibility for ion-exchange function, as illustrated in Figure 3.
This is analogous to the Lattice-Boltzmann model of discretizing
and localizing dynamics of polymeric chains over a grid.
[1] Liang Gao, Chi-Ying Vanessa Li, and Kwong-Yu Chan,
"Polystyrene Sulfonate threaded in MIL-101Cr(III): a Cationic
Polyelectrolyte Synthesized Directly into a Metal-Organic
Framework", Chem. Mater. DOI: 10.1021/cm504623r. Publication Date
(Web): April 30, 2015.
[2] L. Gao, C.Y. V. Li, K.Y. Chan, and Z.N. Chen, "Metal-Organic
Framework Threaded with Aminated Polymer Formed in Situ for Fast
and Reversible Ion Exchange", J. Am. Chem. Soc. 136 (2014)
7209-7212.
Chair: Prof. Stefan Jurga
/264/
Date: Wednesday 2016.02.10, 12:00
Speaker: Dr hab. Izabela Szafraniak-Wiza
Affiliation: Institute of Materials Science and Engineering,
Poznań University of Technology
Title: Ferroelectric perovskites for modern electronics
Abstract: Ferroelectric materials offer a wide range of useful
properties such as spontaneous polarization, pyroelectric,
piezoelectric, and electro-optic effects that can be applied in
non-volatile memories, actuators, transducers, and thermal
sensors. From technological point of view several important issues
concerning applications of ferroelectrics (like size effects, one
dimensional structures, lead-free materials, multiferroic bismuth
ferrite) are important and will be presented in this talk.
Perovskites and perovkite-like compounds are conventionally
obtained by solid-state reactions or wet-chemistry. The methods
are related to high production costs and have serious
disadvantages. A much less expensive alternative to the
chemistry-based techniques is a direct synthesis from respective
oxides at room temperature via mechanically triggered chemical
reaction. The room temperature synthesis lowers the fabrication
costs, eliminates the undesirable losses of volatile elements and
enables the control of chemical and stoichiometry composition. The
method has been recently used to obtain nanocrystalline
electroceramic materials of perovskite structure like BiFeO3,
PZT, Ba(Ti,Ca)O3, Ba(Fe1/2Nb1/2)O3,
Bi3TiNbO3. The influence of the mechanochemical synthesis or
mechanical activation on the final properties of the nanopowders
and/or ceramics (obtained from those powders) will been
discussed.
Chair: Prof. Maciej Krawczyk
/263/
Date: Friday 2016.01.29, 12:00
Speaker: Prof. Jan Peřina Jr.
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Science of the Czech
Republic, Olomouc, Czech Republic
Title: Coherence and dimensionality of twin beams generated from
depleted pump fields
Abstract: Using the model of parametric interaction based on the
spatio-spectral Schmidt modes and generalized parametric
approximation, we analyze coherence and mode structure of
ultra-intense twin beams generated in the regime with pump
depletion. We show that the increase of spatial and spectral
coherence with the increasing pump power observed for moderate
powers is replaced by the decrease for the pump powers at which
pump depletion occurs. This behavior of coherence is opposed to
that exhibited by the number of spatio-spectral modes effectively
constituting the twin beam. The conditions for maximal coherence
are analyzed considering pump-beam parameters (spectral width,
transverse radius). The existence of additional coherence maxima
occurring at even higher pump powers is predicted and explained by
the oscillatory evolution of the modes' populations. Comparison
with the experimental results is discussed.
Chair: Prof. Adam Miranowicz
/262/
Date: Wednesday 2016.01.27, 12:00
Note: A short tutorial on "How to apply for ERC grants"
will follow at 14:30.
Speaker: Dr Stefan Gillessen
Affiliation: Max-Planck-Institut für extraterrestrische Physik,
Garching, Germany
Title: The Galactic Center: A unique astrophysical laboratory
Abstract: [PDF] Located at 8kpc only, the Galactic
Center allows studying a galactic nucleus in unparalleled detail.
With the advent of high-resolution, near-infrared instrumentation
in the last decade it became possible to follow individual stellar
orbits around the radio source Sgr A* with orbital periods as
short as 12 years. The orbits provide compelling evidence for the
massive black hole paradigm. The next generation near-infrared
instrument GRAVITY aims at interferometrically combining the light
of the four telescopes of ESO's VLT. The higher resolution will
allow monitoring stellar orbits with orbital periods of 1 year
only, and the relativistic prograde periastron precession gets
accessible. The astrometric accuracy of GRAVITY is of order of the
event horizon size of Sgr A*. This means that we might have access
to measuring the spin of Sgr A*. In the past few years the small
gas cloud G2 has been approaching Sgr A*. We were able to follow
the tidal evolution of G2 for a decade, beautifully showing how
the object got stretched ever more and how it passed the point of
closest approach in 2014. The cloud is a unique probe of Sgr A*'s
atmosphere, and we have observational hints that gas passing so
close to Sgr A*
experiences a drag force.
Recommended popular articles:
Gas cloud in the galactic centre
ERC Starting Grant for Stefan Gillessen
Obiad czarnej dziury szybko się zbliża
Chair: Dr Agata Karska
/261/
Date: Wednesday 2016.01.13, 12:00
Speaker: Dr Agata Karska
Affiliation: Astronomical Observatory of AMU
Title: Interstellar molecules: A key to understand how stars like
our Sun form
Abstract: Stars form continuously in the dense and cold molecular
clouds in our Galaxy. At the earliest stages of their formation,
the proto-stars are surrounded by large amounts of dust and gas
which make them invisible in the optical light. The most useful
are in fact far infrared wavelengths containing the maximum of the
dust emission and the key molecular transitions. The latter are a
powerful tool to investigate the physical conditions of the gas
and thus the physical phenomena at play during the star formation.
In my talk, I will present the state-of-the-art spectroscopy of
star forming regions from the Herschel Space Telescope. I will
show how the observations of interstellar molecules such as water
and carbon monoxide help astronomers to understand the physics of
essentially hidden stages of star formation.
Popular articles in Polish:
Na początku jest woda
Zanim zabłysną
Astronomka z Poznańia asystuje przy narodzinach
gwiazd
Chair: Prof. Maciej Krawczyk
/260/
Date: Friday 2016.01.8, 12:00
Speaker: Dr Koji Maruyama
Affiliation: Osaka City University, Osaka, and Waseda University,
Tokyo, Japan
Title: Hamiltonian identification under limited access with
minimal pre-knowledge
Abstract: In order to control a quantum system, we need the full
information on its Hamiltonian. Yet, how can we know all the
entries of a Hamiltonian matrix, especially when the system is
large and our access is limited? The problem of Hamiltonian
identification under limited access has recently been studied
quite actively. Here, after reviewing our results, we ask a more
ambitious question along the same lines; what if we don’t know
anything about the system and we still attempt to estimate its
Hamiltonian through a small gateway? We shall discuss how we can
probe such an ‘untouchable’ system E through a small gateway
system S, paying a close attention to the equivalence class
induced by the limitedness of access. The insight obtained hereby
would open up a possibility of controlling a large quantum system
with only a few parameters.
Chair: Prof. Adam Miranowicz
/259/
Date: Friday 2016.01.8, 10:00
Speaker: Dr Koji Maruyama
Affiliation: Osaka City University, Osaka, and Waseda University,
Tokyo, Japan
Title: Maxwell’s demon and the physics of information
Abstract: The paradox of Maxwell’s demon is probably the most famous example, in which physics (particularly thermodynamics) and the concept of information are linked. The tricky point of this paradox is in the necessity of the quantitative consideration of information acquisition by measurement. The related argument strengthened our notion that information processing is physical, and formed a firm basis of the science of quantum information. We will review the history of the efforts to resolve the paradox, the final exorcism by Landauer and Bennett, as well as some interesting consequences of the 2nd law [1].
[1] Koji Maruyama, Franco Nori, and Vlatko Vedral, Rev.
Mod. Phys. 81, 1 (2009) .
Chair: Prof. Adam Miranowicz
/258/
Date: Thursday 2016.01.7
Speaker: Dr Koji Maruyama
Affiliation: Wolfram Research, Japan
Title: Introduction to Mathematica 10 - the wonderland of
computer algebra system
Abstract: Mathematica is a software that was originally developed
for researchers in mathematics and physics. Since its first
release 26 years ago, it has evolved so greatly that it can now be
applied to virtually everything, such as data visualisation, image
processing, financial engineering, machine learning, etc., to name
a few. We will cover as many functions it has as possible to
impress you, and will answer any questions.
The Mathematica notebook of this presentation can be downloaded
from
https://download.wolfram.com/?key=62BX94
/257/
Date: Thursday 2015.12.10, 12:00
Speaker: Dr Joachim Gräfe
Affiliation: Max-Planck-Institut für Intelligente Systeme,
Stuttgart, Germany
Title: Static and Dynamic X-Ray Microscopy for Magnetic
Nanostructures
Abstract: Magnetic nanostructures, that are patterned on the
length scale of the dipole and exchange interaction, have gained
significant scientific interest in the past years [1-6]. These
nanostructures have great potential for technological applications
in data processing and storage, and spintronics [1-6]. However,
the measurement of their microscopic magnetisation behaviour is
challenging. For this task we use a combination of fast MOKE based
first-order reversal curve (FORC) measurements, that we recently
developed [7], and x-ray microscopy with XMCD contrast at our own
endstation MAXYMUS@BESSY. FORC allows the magnetic separation of
individual magnetisation reversal processes without the need for
high lateral resolution. X-ray microscopy on the other hand yields
a detailed nanoscopic image of the magnetisation and allows the
observation of magnetisation dynamics on a picosecond timescale.
To showcase the capabilities of these two powerful methods an antidot lattice (ADL) based magnonic crystal is discussed, among others. FORC and static x-ray imaging provide a detailed insight into the very complex and orientation dependent magnetisation reversal processes of ADL samples. The full magnetisation reversal is achieved by a combination of several reversible and irreversible steps that could not have been distinguished by conventional magnetometry. Subsequently, the time resolution capabilities of x-ray microscopy are leveraged to directly observe the individual spin wave modes in the magnonic crystal in the range from 250 MHz up to 8 GHz. Finally, the understanding of the static and dynamic magnetisation behaviour of these magnonic crystals allows tuning the magnon propagation length within the ADL in a range from 0.5 to 15 µm, thus, realising a simple spin wave filter.
[1] Lenk, B. et al.: Phys. Rep. 507 (2011), 107
[2] Haiming, Y. et al.: Nat. Commun. 4 (2013), 2702
[3] Heyderman, L. J. et al.: Phys. Rev. B 73 (2006), 214429
[4] Schwarze, T.; Grundler, D.: Appl. Phys. Lett. 102 (2013), 22
[5] Manzin, A.; Bottauscio, O.: J. Phys. D - Appl. Phys. 45 (2012), 095001
[6] Haering, F. et al.: Nanotechnology 24 (2013), 055305
[7] Gräfe, J. et al.: Rev. Sci. Instr. 85 (2014), 023901
Chair: Prof. Maciej Krawczyk
/256/
Date: Wednesday 2015.12.9, 12:00
Speaker: Prof. Oksana Gorobets
Affiliations:
Institute of Magnetism, National Academy of Sciences of Ukraine, Kiev, Ukraine
and National Technical University of Ukraine. Kiev, Ukraine
Title: Effects of magnetic field at metal-aqueous electrolyte
interface
Abstract: The seminar will be focused on the magneto-hydrodynamic
stirring of electrolyte in the combined electric and magnetic
fields. We will present the estimations of the order of magnitude
of the gradient magnetic force, gradient paramagnetic force,
Lorentz force and damping force acting on ions embedded in aqueous
electrolytes. The focus will be given to influence of magnetic
field on the effectively para- and diamagnetic products of
electrochemical reactions and the effects of phase separation
under inhomogeneous magnetic field and Earth gravitation will be
discussed. We will discuss also the influence of stray magnetic
field of the ferromagnetic electrodes on a deposit structure and
electrokinetic effects under inhomogeneous magnetic field.
Chair: Prof. Maciej Krawczyk
/255/
Date: Friday 2015.12.4, 12:00
Speaker: Prof. Manfred Albrecht
Affiliation: Institute of Physics, University of Augsburg, D-86159
Augsburg, Germany
Title: Future concepts and materials for magnetic data storage
Abstract: [PDF] Due to the increasing demand in
high-density recording media, magnetic thin films with high
magnetic anisotropy are widely studied in order to overcome the
superparamagnetic effect. To fulfill the requirements of thermal
stability, hard magnetic alloys, i.e. FePt alloys in the L10 phase
are promising candidates as storage layer. However, owing to the
large magnetic anisotropy, the magnetic field required to reverse
the magnetization of the media may become higher than the field
provided by a conventional recording head. To solve this,
so-called writeability issue, the concepts of exchange-coupled
composite (ECC) media as well as bit patterned media based on L10
FePt [1] were suggested, which will be discussed in this
presentation.
Furthermore, ultrafast magnetization switching is at the heart of both modern information storage technology and fundamental science. In this regard, it was recently observed that ultra-fast magnetization reversal processes can be induced by circularly polarized laser pulses in amorphous ferrimagnetic GdFeCo alloy thin films [2]. This novel observation resulted in a broad range of exciting and challenging fundamental questions, and may enable new applications based on ultra-fast spintronics. An overview of our activities on all-optical switching in amorphous ferrimagnetic Tb-Fe alloy films [3-5] will be presented.
[1] C. Brombacher, M. Grobis, J. Lee, J. Fidler, T. Eriksson, T. Werner, O. Hellwig, and M. Albrecht, Nanotechnology 23, 025301 (2012).
[2] C. D. Stanciu, F. Hansteen, A. V. Kimel, A. Kirilyuk, A. Tsukamoto, A. Itoh, and Th. Rasing, Phys. Rev. Lett. 99, 047601 (2007).
[3] A. Hassdenteufel, B. Hebler, C. Schubert, A. Liebig, M. Teich, M. Helm, M. Aeschlimann, M. Albrecht, and R. Bratschitsch, Advanced Materials 25, 3122 (2013).
[4] C. Schubert, A. Hassdenteufel, P. Matthes, J. Schmidt, M. Helm, R. Bratschitsch, and M. Albrecht, Appl. Phys. Lett. 104, 082406 (2014).
[5] A. Hassdenteufel, J. Schmidt, C. Schubert, B. Hebler, M. Helm,
M. Albrecht, and R. Bratschitsch, Phys. Rev. B 91, 104431 (2015).
Chair: Prof. Maciej Krawczyk
/254/
Date: Wednesday 2015.11.25, 12:00
Speaker: Dr Andriy Serebryannikov
Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
Title: Hybrid propagation, scattering, reflection and absorption
regimes in advanced photonic structures
Abstract: The talk is dedicated to the hybrid propagation,
scattering, reflection, and absorption regimes that can be
obtained in the advanced but still simple photonic structures and
their microwave prototypes. Various manifestations of the
diffraction inspired asymmetric transmission, a general phenomenon
arising when using linear, isotropic, passive materials together
with spatial inversion symmetry breaking, will be considered in
the different structures, which include photonic crystal gratings,
gratings made of ultralow-index materials, gratings based on
hole-array metamaterials, and thin metallic gratings with a single
subwavelength hole. The basic scenarios of directional selectivity
achievable with the aid of these structures and their possible
applications will be discussed. Then, the attention will be paid
to ultrathin chiral metamaterials based on the coupled arrays of
subwavelength resonators, which enable efficient polarization
conversion and relevant channel and direction selectivity. The
next topics will include reflection-enhanced absorption in
photonic crystals made of polar dielectrics, multiple slow waves
in graded-index photonic crystals, invisibility obtainable using
high-index shells, and surface plasmons in deep annular-hole
arrays. Finally, the transmission-mode spatial (angular) filtering
in regular photonic crystals will be discussed alongside the
reflection-mode spatial filtering, blazing, and splitting in thin
reflector-backed gratings.
Chair: Prof. Maciej Krawczyk
/253/
Date: Wednesday 2015.10.28, 12:00
Speaker: Dr Michał Studziński
Affiliation: Uniwersytet Gdański, Krajowe Centrum Informatyki
Kwantowej w Gdańsku
Title: Group representation approach to universal quantum cloning
machines
Abstract: Quantum information cannot be copied perfectly, in
contrast with information from the "classical world". In other
words, one is not able to copy perfectly an arbitrary quantum
state. In terms of monogamy, if one wants to prepare some number
of copies of the initially unknown quantum state, fidelities of
cloning cannot be all equal to 1, there is a trade-off. This basic
feature is known as ’no-cloning theorem’ and was recognized by
Wootters, Zurek and Dieks. But still there is possibility for
imperfect cloning. Using group-theory formalism, we show that the
allowed region for fidelities can be expressed in terms of
overlaps of pure states with irreducible representations of the
partially transposed permutation operators. Additionally, it is
sufficient to take pure states with real coefficients only, which
makes calculations simpler. To obtain the allowed region, we make
a convex hull of possible ranges of fidelities related to a given
irreducible representations.
Chair: Prof. Andrzej Grudka
/252/
Date: Wednesday 2015.10.21, 12:00
Speaker: Prof. Andrzej Grudka
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Do black holes create polyamory?
Abstract: Of course not, but if one believes that information
cannot be destroyed in a theory of quantum gravity, then we run
into apparent contradictions with quantum theory when we consider
evaporating black holes. Namely that the no-cloning theorem or the
principle of entanglement monogamy is violated. Here, we show that
neither violation need hold, since, in arguing that black holes
lead to cloning or non-monogamy, one needs to assume a tensor
product structure between two points in space-time that could
instead be viewed as causally connected. In the latter case, one
is violating the semi-classical causal structure of space, which
is a strictly weaker implication than cloning or non-monogamy.
This is because both cloning and non-monogamy also lead to a
breakdown of the semi-classical causal structure. We show that the
lack of monogamy that can emerge in evaporating space times is one
that is allowed in quantum mechanics, and is very naturally
related to a lack of monogamy of correlations of outputs of
measurements performed at subsequent instances of time of a single
system. This is due to an interesting duality between temporal
correlations and entanglement. A particular example of this is the
Horowitz-Maldacena proposal, and we argue that it need not lead to
cloning or violations of entanglement monogamy.
Chair: dr Karol Bartkiewicz
/251/
Date: Wednesday 2015.10.14, 12:00
Speaker: Dr Ronan Lefort
Affiliation: Université de Rennes 1, France
Title: Confinement-induced nano-segregation of amphiphilic binary
liquids
Abstract: Environment care has now become a global societal
challenge, on which physics and chemistry can turn to be leading
actors and innovation leaders, especially in the domains of
energetic transition, green nanoscience or ecomaterials. As an
example, a great attention has been recently paid to the control
of volatile organic compounds (VOCs) in home and working
environments. Breakthroughs in the captation of VOCs have been
achieved thanks to the mastering of novel porous nanomaterials,
able to selectively filter or coadsorp molecular species. However,
several scientific locks remain, related to the intricate balance
of amphiphilic interactions and hydrogen-bond structures
responsible for the behaviour of gaseous or liquid mixtures in
nanopores. The physical parameters governing the nanostructures
and the molecular dynamics of complex binary liquids confined in
porous solids remain essentially unknown. We present here a
general view of a model molecular binary system made of a ternary
alcohol and an aprotic liquid, confined inside nanoporous silicas
or carbons. Through a global experimental approach, we detail how
the subtle balance of hydrophilic or -phobic interactions with
interfaces in a nanoporous solid can lead to surprising
nanostructures in the binary, and strongly affect both the
hydrogen bonds network and the molecular dynamics of the system.
We tentatively propose general routes for controlling coadsorption
and/or nanofiltration of these complex binaries by tailoring
specific nanoporous interfaces.
Chair: Dr hab. Jacek Kubicki
/250/
Date: Friday 2015.10.09, 10:00
Speaker: Prof. Yuri Oganessian
Affiliation: Flerov Laboratory of Nuclear Reactions, Joint
Institute for Nuclear Research, Dubna, Russia
Title: Discovery of Super Heavy Elements
Abstract: One of the fundamental outcomes of the modern nuclear
theory of is the prediction of the "stability islands" in the
domain of the hypothetical super heavy elements. The enhanced
stability has been expected for the deformed nuclei near Z=108 and
N=162, yet much stronger effect has been predicted for heavier
spherical nuclei close to the shells Z=114 and N=184. The talk is
devoted to the experimental verification of these predictions –
the synthesis and study of both the decay and chemical properties
of the new elements.
The synthesis of the heaviest nuclei with high neutron
excess has been carried out in the fusion reactions of U and the
isotopes of man-made elements: from Np up to Cf with the Ca-48
projectiles in 2000-2015. The decay properties of the 52
synthesized nuclei – the isotopes of elements 104-118 - obtained
in 48Ca-induced reactions presents direct experimental evidence of
the existence of the super heavy nuclei that considerably expand
the Periodical Table of the chemical elements.
Simultaneously in the chemical studies of elements 112-114
by methods of absorption gas chromatography the influence of the
“relativistic effect” on the chemical properties of the super
heavy elements was obtained for the first time. The possibilities
of further theoretical and experimental investigations in close
collaboration with many European and American laboratories
connected with construction in Flerov Laboratory “Super Heavy
Element Factory” are also discussed.
In the talk are used the results obtained in FLNR (JINR,
Dubna) in collaboration with LLNL, (Livermore, USA), ORNL
(Oak-Ridge, USA), and Vanderbilt University (Nashville, USA),
Texas A |
M University (College Station, USA) as well as GSI
(Darmstadt, Germany), PSI (Villigen, Switzerland) and RIKEN
(Tokyo, Japan).
Dodatkowe informacje: Profesor Oganessian należy do liderów w skali światowej w
dziedzinie wytwarzania i badania własności fizycznych i
chemicznych super ciężkich pierwiastków. Super ciężkie jądra
atomowe tych pierwiastków stanowią obiekt zaawansowanych badań
teoretycznych i eksperymentalnych prowadzonych w najlepszych
centrach badawczych - głównie w Dubnej, USA i Niemczech. Profesor
jest świetnym wykładowcą potrafiącym z pasją przedstawiać
najnowsze wyniki badań.
Chair: Prof. Wojciech Nawrocik
/249/
Date: Wednesday 2015.10.7, 12:00
Speaker: Dr Kenneth P. Mineart
Affiliation: Department of Chemical and Biomolecular Engineering,
North Carolina State University, Raleigh, USA
Title: Understanding and Controlling the Morphology of a
Midblock-Sulfonated Block Ionomer
Abstract: Block copolymers containing ionic pendant groups, or
block ionomers, have become increasingly popular due to their
potential application as fuel cell and water desalination
membranes, as well as components in photovoltaic devices and
polymeric actuators. Block ionomers hold promise in these
applications because of their inherent ability to form separate
ionic and nonpolar microdomains at nanoscale dimensions.
Segregation of ionic and nonpolar segments enables simultaneous
water, or ion, transport and mechanical robustness. This is
especially true when ionic segments are located in the midblock of
a multiblock copolymer. The ionic and nonpolar blocks are,
however, highly incompatible, which can lead to long-term
metastable morphologies. While thermal annealing is typically used
to refine block copolymer self-assembly to equilibrium structures,
most block ionomers have inaccessible glass transition
temperatures, thereby making thermal annealing ineffective. The
establishment of morphological control in block ionomers
represents the main challenge preventing widespread use. Here, we
explore a variety of nanostructures formed during solution casting
and then investigate a facile means by which to equilibrate the
morphological behavior of a midblock-sulfonated pentablock
ionomer. A combination of transmission electron microscopy and
tomography (TEM/T) and small-angle X-ray scattering (SAXS) are
used to probe nanostructural features present in films produced
from different casting strategies. Results indicate that
solvent-templating of nano-features following solution casting is
prominent, but that subsequent solvent vapor annealing can be
effective in equilibrating the morphology. To the best of our
knowledge, these results provide the first evidence of
morphological control/refinement in a block ionomer of
commercially relevant molecular weight.
Chair: Prof. Adam Patkowski
/248/
Date: Tuesday 2015.09.08, 12:00
Speaker: Dr Paweł Zawadzki
Affiliation: Oxford University, UK
Title: Mechanisms of bacterial chromosome repair and segregation
studied by smFRET and Super-Resolution microscopy
Abstract: The single-molecules techniques are revolutionizing our
understanding of biological processes and molecular mechanisms
used by individual protein machines. I will introduce smFRET
method and show how it was used to “observe” multiple
conformational changes within recombination complex, acting in
late stages of bacterial chromosome segregation, directly showing
how recombination is activated and regulated. On the other hand,
the real challenge in biology is to observe how individual
proteins perform their function within living cell. I will present
super-resolution microscopy and the ways I explore it to
understand how individual UvrA and UvrB initiate pathway of DNA
repair. I will show how these novel biophysical methods are
changing our understanding of DNA repair process.
Chair: Prof. Jacek Gapiński
/247/
Date: Monday 2015.07.13, 12:00
Speaker: Prof. Keith E. Gubbins
Affiliation: Department of Chemical |
Biochemical Engineering,
North Carolina State University, Raleigh, USA
Title: Corresponding States Theory for Thin Adsorbed Films
Chair: Prof. Małgorzata Śliwińska-Bartkowiak
/246/
Date: Friday 2015.07.3, 12:00
Speaker: Dr Ken Onda
Affiliation: Interactive Research Center of Science, Graduate
School of Science and Engineering, Tokyo Institute of Technology,
Japan
Title: Photoinduced Dynamics in Organic Solid Materials Studied by
Time-resolved Infrared Vibrational Spectroscopy
Abstract: Recently photoinduced dynamics in organic solid
materials have attracted more attention in terms of not only the
fundamental physics but also the application to low-cost
photo-electronic devices. However, photoinduced processes in
organic materials are more complicated than those in inorganic
solid materials due to their flexible and soft structures [1].
Time-resolved infrared vibrational spectroscopy is one of the
ideal tools for studying these dynamics because a vibrational peak
is sensitive to both local charge and structure in an organic
solid material. We applied this method to the photoinduced phase
transition in organic crystals and found that the different
dynamics of charge and structure accompanied by the phase
transition [2-4]. We also studied the initial photoexcited
processes in metal complexes including a spin crossover complex
and found the state which has not observed by the other methods
[5]. Moreover, we confirmed that the results obtained by
time-resolved vibrational spectroscopy is in good agreement with
those by more structure sensitive time-resolved method, that is,
time-resolved electron diffraction [6].
[1] K. Onda, et al. Acc. Chem. Res. 47, 3494 (2014).
[2] Y. Matsubara, et al. J. Phys. Soc. Jpn. 80, 124711 (2011).
[3] N. Fukazawa, et al. J. Phys. Chem. C 116, 5892 (2012).
[4] N. Fukazawa, et al. J. Phys. Chem. C 117, 13187 (2013).
[5] T. Mukuta, et al. Inorg. Chem. 53, 2481 (2014).
[6] M. Gao, et al. Nature, 496, 343 (2013).
Chair: Dr hab. Jacek Kubicki
/245/
Date: Wednesday 2015.06.24, 12:00
Speaker: Dr Felix Pollock
Affiliation: Monash University in Melbourne, Australia
Title: What a biased two-level system can tell you about its
environment
Abstract: Quantum process tomography (QPT), the full experimental
determination of a quantum process, is usually used for
benchmarking known systems. Here, I show how, by applying a large,
controllable external bias, QPT of a two-level probe system can be
used to determine a great deal about an unknown environment –
including properties of its state and spectrum. The protocol I
will discuss relies on few assumptions and could thus be applied
to many systems of experimental interest, such as Bose-Einstein
condensates, superconducting circuits and atoms in optical
cavities. Within this talk, I will also discuss how one can do
tomography for processes with initial correlations and hence those
which are non-Markovian.
Chair: Dr Karol Bartkiewicz
/244/
Date: Wednesday 2015.06.10, 12:00
Speaker: Dr Fabrice Herpin
Affiliation: University of Bordeaux, France
Title: Results from the Herschel Space Observatory mission
Abstract: The mission of the ESA Herschel satellite was completed
in April 2013 after quite 4 years of activity. However, the
incredible results of this far-infrared space observatory continue
to revolutionize our view of the Universe. In particular, our
knowledge of our Galaxy, of the stars and of our solar system has
made significant progress thanks to the work carried out with this
telescope, especially by the european teams. The formation
mechanisms and the evolution of stars, of a few solar masses or
greater, have revealed themselves a little more precisely: thanks
to Herschel images and spectroscopic observations we now have a
more global view of the genesis of stars and of their chemistry.
The first complete observations of the water molecule allowed us
to estimate the very significant amounts of water that exist in
any planetary system in formation, but also to address the crucial
question of the origin of water (and therefore life) on our own
Earth.
Chair: Dr Agata Karska
/243/
Date: Tuesday 2015.06.02, 12:00
Speaker: Prof. Ryszard Tanaś
Title: Can Bell’s inequalities be violated with classical fields?
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Abstract: Recently a number of papers appeared in which the notion
of "classical entanglement" and its role in optical processes
has been discussed. There are some experimental results already
published showing that "classical entanglement" is sufficient to
violate Bell’s inequalities. This can have important implications
for commonly accepted interpretation of some physical phenomena.
The talk is aimed to present some of these, still controversial,
results.
Chair: Prof. Adam Miranowicz
/242/
Date: Tuesday 2015.05.26, 12:00
Speaker: Prof. Nitash Balsara
Position: Charles W. Tobias Chair in Electrochemistry
Affiliation: Chemical and Biomolecular Engineering, University of
California, Berkeley, USA and Lawrence Berkeley National
Laboratory
Title: Batteries and Biofuels in the Clean Energy Landscape
Chair: Prof. Michał Banaszak
/241/
Date: Wednesday 2015.05.20, 12:00
Speaker: Dr Mirosław Łabuz
Affiliation: Wydział Matematyczno-Przyrodniczy, Katedra Fizyki
Teoretycznej, Uniwersytet Rzeszowski
Title: Internal parity symmetry and degeneracy of Bethe Ansatz
strings in the isotropic heptagonal magnetic ring
Abstract: The exact Bethe eigenfunctions for the heptagonal ring
within the isotropic XXX model exhibit a doubly degenerated energy
level in the three-deviation sector at the centre of the Brillouin
zone. I will demonstrate an explicit construction of these
eigenfunctions by use of algebraic Bethe Ansatz, and point out a
relation of degeneracy to parity conservation, applied to the
configuration of strings for these eigenfunctions. Namely, the
internal structure of the eigenfunctions (the 2-string and the
1-string, with opposite quasimomenta) admits generation of two
mutually orthogonal eigenfunctions due to the fact that the
strings which differ by their length are distinguishable objects.
Chair: Prof. Adam Miranowicz
/240/
Date: Wednesday 2015.05.13, 12:00
Speaker: M.Sc. Tomasz Wasak
Affiliation: Katedra Optyki Kwantowej i Fizyki Atomowej, Instytut
Fizyki Teoretycznej Uniwersytetu Warszawskiego
Title: Cauchy-Schwarz inequality and particle entanglement
Abstract: The creation of ensembles of entangled particles
triggered the studies of fundamental aspects of quantum mechanics.
The ability to generate non-classical correlations between atoms
opened the possibility for their practical applications in
non-trivial ways, for example in quantum computation or
ultra-precise metrology. However, before the implementation stage,
we must first make sure that the entanglement is present in the
system, which is often a difficult task.
In this seminar I will present the experiments that were conducted
to verify existence of non-classical correlations in ultracold
atomic systems. Then I provide a simple and experimentally
accessible criterion for particle entanglement in many-body
systems. This is based on a violation of the Cauchy-Schwarz
inequality for the second order correlation function. It applies
to any system of identical bosons with either fixed or fluctuating
number of particles, provided that there is no coherence between
different number states.
Chair: Prof. Adam Miranowicz
/239/
Date: Wednesday 2015.05.06, 12:00
Speaker: Dr Paweł Jakubczyk
Affiliation: Wydział Matematyczno-Przyrodniczy, Katedra Fizyki
Teoretycznej, Uniwersytet Rzeszowski
Title: Entanglement of magnons in the Heisenberg XXX chain
Abstract: I will present very simple analytical formulas for
calculation of multipartite and bipartite entanglement of
one-magnon states in quantum spin systems. Regarding the
multipartite entanglement I will present formulas for global
entanglement and N-concurrence and show that they are mutually
related. In the bipartite case, I will give formulas for
I-concurrence and negativity, and show that they are also
scalable. For one-magnon Schur-Weyl states I will show that the
bipartite entanglement structure is completely coded in the
corresponding Young tableau.
Chair: Prof. Adam Miranowicz
/238/
Date: Wednesday 2015.04.29, 12:00
Speaker: Prof. Piotr Śniady
Affiliation: Faculty of Mathematics and Computer Science, AMU
Title: Joys and sorrows of a quantum computer owner (Radości i
smutki z posiadania komputera kwantowego)
Abstract: Some problems (such as factorization of large numbers
into a product of primes) which seem to be difficult for a
classical computer turned out to be very simple for a quantum
computer. Is it a general pattern or are there some problems which
are too difficult even for quantum computers?
Chair: Prof. Adam Miranowicz
/237/
Date: Tuesday 2015.04.21, 12:00
Speaker: Prof. K. Guslienko
Affiliation: Universidad Del Pais Vasco/ Euskal Herriko
Unibertsitatea (UPV/EHU), San Sebastian, Spain
Title: Collective vortex excitations in magnetostatically coupled
dot clusters
Abstract: Low frequency gyrotropic dynamics (100 MHz range) in
arrays of the interacting magnetic vortex state dots are
considered. The interdot dynamical magnetostatic interactions are
accounted in the form of explicit multipole decompositions on the
inverse dot center-to-center distance. Particular case of the dot
clusters consisting of 3 or 4 laterally placed cylindrical
ferromagnetic dots on a nonmagnetic substrate in the form of
equilateral triangles or squares is calculated. The
eigenfrequencies of collective magnetic vortex oscillations are
calculated analytically and compared with recent experiments
conducted on the clusters of permalloy dots.
Chair: Prof. Maciej Krawczyk
/236/
Date: Tuesday 2015.04.14, 12:00
Speaker: Dr V. Kruglyak
Affiliation: University of Exeter, Exeter, UK
Title: Towards graded-index magnonics: Steering spin waves in
networks of magnonic waveguides
Authors: C. S. Davies,1 A. Francis,1 A. V. Sadovnikov,2
S. V. Chertopalov,3 M. T. Bryan,4 S. V. Grishin,2 D. A.
Allwood,4 S. A. Nikitov,2,5 Yu. P. Sharaevskii2, and V.
V. Kruglyak1
1School of Physics, University of Exeter, Stocker road, Exeter, EX4 4QL, United Kingdom
2Laboratory "Metamaterials," Saratov State University, Saratov 410012, Russia
3Donetsk National University, 24 Universitetskaya Street, Donetsk, 83001, Ukraine
4Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom
5Kotel'nikov Institute of Radioengineering and Electronics,
Russian Academy of Science, Moscow 125009, Russia
Abstract: [PDF] The spin-wave dispersion is
inherently complex and anisotropic, depending on both several
magnetic parameters of the magnonic medium and the angle between
the spin-wave vector and effective magnetic field. We have used
time-resolved scanning Kerr microscopy and micromagnetic
simulations to study the propagation of spin waves across
Permalloy and yttrium-iron-garnet (YIG) waveguides, arranged to
form junction structures and biased asymmetrically. We demonstrate
that the non-uniformity of the internal magnetic field and
magnetization inherent to patterned magnetic structures can create
a medium of graded refractive index for propagating magnetostatic
waves and can be used to steer their propagation in magnonic
architectures. The character of the non-uniformity can be tuned
and potentially programmed using the applied magnetic field. Thus,
our findings suggest a possibility of a novel reconfigurable
computing and / or signal processing technology based on the
principles of the graded-index magnonics. [PDF]
Chair: Prof. Maciej Krawczyk
/235/
Date: Tuesday 2015.03.31, 14:00
Speaker: Prof. Dr Peter Laggner
Affiliation: Director of the Nanosystem Solutions Bruker AXS,
Karlsruhe, Germany
Title: Advanced Laboratory SAXS Technology. Bruker Instrumentation
and Applications
Chair: Prof. Maciej Kozak
/234/
Date: Wednesday 2015.03.25, 10:00
Speaker: Dr inż. Piotr Kuświk
Affiliation: Zakład Cienkich Warstw, Instytut Fizyki Molekularnej
PAN w Poznańiu
Title: Magnetyczne układy cienkowarstwowe o lokalnie
modyfikowanych właściwościach i ich zastosowania
Abstract: Magnetyczne układy warstwowe i wytwarzane z nich
nanostruktury są przedmiotem badań wielu laboratoriów.
Zainteresowanie tymi układami wynika z licznych, już
zrealizowanych oraz perspektywicznych, zastosowań. Dotyczą one
głównie technologii informatycznych oraz różnego typu elementów
spintronicznych. Szczególnie interesujące są takie układy
warstwowe, w których lokalna modyfikacja właściwości magnetycznych
w płaszczyźnie warstw prowadzi do uzyskania specyficznej struktury
magnetycznej, której realizacja w układach jednorodnych nie jest
możliwa.
Omówionych zostanie kilka przykładów modyfikacji anizotropii lub
oddziaływania w układach warstwowych wykazujących anizotropię
prostopadłą (Au/Co/Au, Pt/Co/Pt). Zmiany anizotropii w
płaszczyźnie struktur uzyskiwano poprzez wytwarzanie warstw z
kontrolowanym gradientem grubości (warstwy klinowe) lub w wyniku
bombardowania jonowego. Bombardowanie warstw Au/Co jonami He lub
Ar przez maski utworzone z regularnej dwuwymiarowej sieci
nanokulek polistyrenowych, pozwoliło wytworzyć jednorodną sieć
sztucznych domen umieszczonych w matrycy o kontrolowanych
właściwościach magnetycznych [1]. Takie struktury są interesujące
ze względu na możliwość wykorzystania do zapisu informacji.
Uzyskanie monotonicznych zmian anizotropii lub oddziaływania
międzywarstwowego pozwala na realizację procesu przemagnesowania
poprzez, kontrolowaną jednorodnym polem magnetycznym, propagację
pojedynczej prostej ściany domenowej [2-3]. Taki kontrolowany ruch
ściany domenowej znajduje szereg potencjalnych zastosowań np.,
jako sensory magnetooporowe [3] lub układy typu lab-on-a-chip
wykorzystujące pole rozproszone nad ściana domenową do transportu
funkcjonalizowanych cząstek magnetycznych.
[1] P. Kuświk inni, Nanotechnology 22, 095302 (2011); Nanotechnology 23, 475303 (2012).
[2] M. Urbaniak i inni, Phys. Rev. Lett. 105, 067202 (2010).
[3] M. Matczak i inni, J. Appl. Phys. 114, 093911 (2013);
Nanoscale Research Letters 9, 395, (2014); Appl. Phys. Lett. 100,
162402 (2012).
Chair: Prof. Maciej Krawczyk
/233/
Date: Wednesday 2015.02.25, 12:00
Speaker: Dr Anna Kowalewska-Kudłaszyk
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Entanglement evolution in nonlinear quantum scissors
systems
Chair: Prof. Maciej Krawczyk
Abstract: We deal with the models of nonlinear quantum
oscillators, described by the Kerr-like nonlinearities. The
oscillators can interact with each other and with external
environment in various ways. Such models are usually associated
with optical nonlinear couplers and discussed in the context of
the properties of light they generate [1]. The Kerr-like models
discussed here can be treated, under some conditions, as
nonlinear quantum scissors, because of their ability to limit
substantially the number of states which are essential in the
system's dynamics [2,3]. Moreover, this mechanism leads to
creation of 2-qubit, 2-qutrit or qutrit-qubit systems for the
discussed models. We will present the necessary conditions for
creation maximally or almost maximally entangled states within
such systems. Additionally, we will present different types of
disentanglement in amplitude and phase damping reservoirs. For the
models considered here we can observe asymptotic entanglement
decay, death or entanglement revival. The conditions for such
behavior will be presented.
[1] J. Perina Jr., J. Perina, Progr. in Opt. 41,
361, (2000).
[2] W. Leoński and A. Kowalewska-Kudłaszyk, Progress in
Optics, 56 131 (2011).
[3] A. Kowalewska-Kudłaszyk and W. Leoński, JOSA B, 31,
1290 (2014).
/232/
Date: Wednesday 2015.02.11, 12:00
Speaker: Dr Pavel Baláz
Affiliation: Polish Academy of Sciences, Institute of Molecular
Physics, Poznań, Poland
and A. Mickiewicz University, Faculty of
Physics, Division of Mesoscopic Physics, Poznań, Poland
Title: Spin current assisted magnetization dynamics in exchange
coupled magnetic layers
Authors: Pavel Baláz and Józef Barnaś
Abstract: It has been shown experimentally, that when two magnetic
layers are separated by a thin nonmagnetic one there is an
exchange (RKKY) coupling between the magnetic layers, which
oscillates between ferromagnetic and antiferromagnetic types when
thickness of the spacing layer is changed [1]. Exchange coupled
magnetic layers have a vast range of applications in spintronics
with number of advantages over single magnetic layers. In magnetic
spin valves they are utilized not just like current polarizers
with negligible stray field but also as composite free layers
offering novel possibilities of manipulation with magnetic moments
by means of spin transfer torque. Thus, in the talk,
current-induced switching of composite free layers with
antiferromagnetic interlayer coupling shall be reviewed [2]. On
the other hand, spin waves in layered magnetic structures have
been extensively studied, both experimentally and theoretically,
in the 80-ties and 90-ties of the past century [3]. Very recently
a possibility of spin current induced spin wave excitation in
magnetic insulators have been demonstrated [4]. Therefore, in the
second part of the talk, influence of spin pumping and spin
current on the spin wave spectra of two exchange coupled
ferromagnetic insulators shall be discussed.
This work has been carried out within the Project NANOSPIN
PSPB-045/2010 supported by a grant from Switzerland through the
Swiss Contribution to the enlarged European Union.
[1] S. S. P. Parkin, N. More, and K. P. Roche, Phys. Rev. Lett. 64, 2304 (1990).
[2] P. Baláz, J. Barnaś, Phys. Rev. B 88, 014406 (2013).
[3] M. Vohl, J. Barnaś, and P. Grünberg, Phys. Rev. B 39, 12003 (1989); J. Barnaś and P. Grünberg, J. Magn. Magn. Mater. 82, 186 (1989).
[4] Y. Kajiwara et al., Nature 464, 262 (2010).
Chair: Prof. Maciej Krawczyk
/231/
Date: Wednesday 2015.02.4, 12:00
Speaker: Dr Olga Malinkiewicz
Affiliation: Saule Technologies Sp. z o.o., Warszawa
Title: Unique properties of halide perovskites
Abstract: Hybrid organic-inorganic perovskites have been
rediscovered recently as great absorbers in solar cells. In these
materials the combination of organic and inorganic components
leads to a material that is both low-cost, solution processable
and an excellent, crystalline semiconductor. Particularly the
solar cell efficiency, now close to 20%, has triggered a huge
research activity on otherwise rather conventional devices. In
this short talk I will try to answer what is the origin of the
unique properties of halide perovskites?
Dodatkowe informacje: Dr Olga Malinkiewicz zajmuje się badaniami nad fotoogniwami
perowskitowymi, będącymi od dwóch lat najbardziej obiecującym
materiałem do konstrukcji nowej generacji baterii słonecznych.
Podczas swojego pobytu na Uniwersytecie w Walencji dr Malinkiewicz
odniosła spektakularny sukces, opracowując nową metodę wytwarzania
fotoogniw perowskitowych na elastycznym podłożu i w niskich
temperaturach. Odkrycie to, szeroko komentowane w polskich
mediach, zostało
opublikowane w zeszłym roku w czasopiśmie Nature Photonics,
a sama autorka uzyskała za nie wiele prestiżowych wyróżnień dla
młodych naukowców. Po powrocie do Polski dr Olga Malinkiewicz
założyła firmę Saule Technologies, której celem jest
komercjalizacja elastycznych fotoogniw perowskitowych.
Przyjazd dr Olgi Malinkiewicz do Poznańia jest związany z planami
współpracy z grupą zajmującą się badaniami fotowoltaicznymi na
Wydziale Fizyki UAM. Dr Malinkiewicz poszukuje także młodych,
zdolnych osób do prowadzenia badań nad wytwarzaniem fotoogniw
perwoskitowych, dlatego w szczególny sposób zapraszamy na
seminarium studentów oraz doktorantów z fizyki i chemii.
Chair: Prof. Maciej Krawczyk
/230/
Date: Wednesday 2015.01.28, 12:00
Speaker: Prof. Michał Kurzyński
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Do biological molecular machines act as Maxwell's demons?
Authors: Michał Kurzyński and Przemysław Chełminiak
Abstract: In the intention of its creator, Maxwell's demon was
thought to be an intelligent being, able to perform work at the
expense of the entropy reduction of a closed operating system. The
perplexing notion of the demon's intelligence was formalized in
terms of memory and information processing by Szilard and
subsequent followers, who pointed out that, in order for the total
system to obey the second law of thermodynamics, the entropy
reduction should be compensated for by, at least, the same entropy
increase, related to the demon's information gain on the operating
system's state. A non-informational formulation of the problem was
proposed by Smoluchowski and popularized by Feynman as the ratchet
and pawl machine, which can operate only in agreement with the
second law. A. F. Huxley and consequent followers adopted this way
of thinking to suggest numerous thermal ratchet mechanisms for the
protein molecular machines' action, but no entropy reduction takes
place for these models. More general models of protein dynamics
have been put forward with a number of intramolecular states
organized in a network of stochastic transitions. Here, the
computer model of such a network is investigated, displaying, like
networks of the systems biology, a transition from the fractal
organization on a small length-scale to the small-world
organization on the large length-scale. This model, when allowing
work performance in a variety of ways, obeys the generalized
fluctuation theorem with entropy reduction and is able to explain
a surprising observation to Yanagida and co-workers that the
myosin II head can take several steps along the actin filament per
ATP molecule hydrolysed. From a broader perspective, the
supposition that (i) a similar mechanism of action is
characteristic for most intrinsically disordered proteins and (ii)
this is the reason for most protein machines to operate as dimers
or higher organized structures could be of especial importance.
Chair: Prof. Michał Banaszak
/229/
Date: Wednesday 2015.01.21, 12:00
Speaker: M.Sc., Eng. Bartłomiej Streszewski
Affiliation: Faculty of Nonferrous Metals, AGH University of
Science and Technology in Kraków
Title: Kinetics of gold nanoparticles formation in aqueous and
microemulsion systems
Abstract: This work presents the results of kinetic measurements
of the Au(III) chloride complex ions reduction with hydrazine and
of the gold nanoparticles formation in aqueous solution and in
microemulsion system of H2O/CTAB/alcohol/hexane. The dynamics
of the gold nanoparticles formation in aqueous solution was
studied using UV-Vis spectrophotometry, DLS and TEM methods.
Nucleation and autocatalytic growth rate constants were determined
by using the modified Finke Watzky model. The TEM measurements and
hydrodynamic radius time evolution have revealed that the
nanoparticles are unstable and grow until they reach a submicron
size. The growth is triggered by the autocatalytic reduction of
Au(I) ions on the surface of the growing particle and aggregation
followed by chemical reaction limited by the Ostwald repining.
Stabilization of gold nanoparticles can be provided by conducting
their synthesis in reverse micelles. During the synthesis micelles
act as nanoreactors and soft templates for the growing particles.
The influence of the molar ratios: w = nH2O:nCTAB and p = nalc:nCTAB of the Au(III) ion initial concentration and the
presence of different alcohols (butanol, pentanol, hexanol or
heptanol) as cosurfactants on the formation kinetics and the
nanoparticle morphology were studied. The particles with the
smallest polydispersity are formed at a low Au(III) ion
concentration and at for low w parameter or in the presence of
alcohols with longer hydrocarbon chain. The particle growth is
limited by the diffusion of the monomers between the micelles,
which can be caused by a low Au(III) ion occupancy per a single
micelle and/or a slow intermicellar exchange rate.
Chair: Prof. Michał Banaszak
/228/
Date: Wednesday 2015.01.14, 12:00
Speaker: Prof. Ryszard Krzyminiewski
Affiliation: Zakład Fizyki Medycznej UAM
Title: Terapia protonowa
Abstract: Przedstawiony zostanie wpływ promieniowania jonizującego
na tkankę biologiczną i jego wykorzystanie w podstawowej
radioterapii nowotworów. Omówione będą sposoby generowania
strumienia protonów oraz zalety i wady zastosowania wiązki
protonów w leczeniu nowotworów. Pokazane zostaną przykłady
ośrodków medycznych w Szwajcarii, Niemczech i Polsce stosujących w
praktyce klinicznej terapię protonową. Zaprezentowane zostaną
własne wstępne wyniki badań wpływu wiązki protonowej na nanoleki
stosowane w terapii nowotworów.
Chair: Prof. Michał Banaszak
/227/
Date: Wednesday 2014.12.17, 12:00
Speaker: Dr Jan Chwedeńczuk
Affiliation: Katedra Optyki Kwantowej i Fizyki Atomowej, Instytut
Fizyki Teoretycznej Uniwersytetu Warszawskiego
Title: Interferometry with independently prepared Bose-Einstein
condensates
Abstract: Whenever the value of an unknown parameter θ is
extracted from a series of experiments, the result is inevitably
burdened by the uncertainty ∆θ. If the system, which
is the subject of measurement consists of unentangled particles,
this uncertainty is bounded by the shot-noise limit. To overcome
this limitation, it is necessary to use a properly entangled
state, which is usually prepared in a dedicated procedure. We show
that quantum correlations arising from the indistinguishability of
bosons are a sufficient resource for the sub-shot-noise
interferometry. To this end, we consider an interferometer, which
operates on two independently prepared Bose-Einstein condensates
with fluctuating numbers of particles. We calculate the
sensitivity obtained from the measurement of the number of atoms
and compare it with the ultimate achievable bound. Our main
conclusion is that even in presence of major atom number
fluctuations, an interferometer operating on two independent
condensates can give very high precision. These observations
indicate a new possibility for an interferometer operating below
the shot-noise limit.
/226/
Date: Wednesday 2014.12.10 at 13:00
Speaker: M.Sc. Krzysztof Wójcik
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Transport properties of T-shaped double quantum dots
Abstract: In my presentation I will mention transport properties
of two quantum dots, coupled to two leads in, so called, T-shaped
configuration. This mean, that one of the dots is embedded between
the leads, while the second is not directly coupled to the leads,
but coupled to the first dot. We restrict ourselves to the linear
response regime. Nevertheless, the physics of such a system is
still very reach and includes the two-stage Kondo effect (the
conductance is enhanced below the Kondo temperature, but becomes
suppressed at even lower temperatures) and Fano-like interference
effects, resulting in a sharp dip in the conductance vs. gate
voltage dependence. Moreover, both effects are strongly influenced
by the presence of magnetism: either in the form of magnetic
field, or encapsulated in ferromagnetic leads. In particular, the
second stage of the Kondo effect can be suppressed (that is, the
usual Kondo effect restored), and a perfect spin polarization of
the conductance can be obtained due to the spin-dependent Fano
anti-resonance condition. I will explain these effects, with
stress put on the case of ferromagnetic leads (results were
obtained with I. Weymann, ZFMezo, UAM). To resolve properly all
the many-body correlations, we employed the Numerical
Renormalization Group method.
/225/
Date: Thursday 2014.11.27, 12:00
Speaker: Dr Tomasz Paterek
Affiliations:
1. Division of Physics and Applied Physics, School
of Physical and Mathematical Sciences, Nanynag Technological
University, Singapore
2. Centre for Quantum Technologies,
National University of Singapore
Title: Physics research and studies at Singapore’s NTU
Abstract: This talk will be devoted to physics research and
facilities at Nanyang Technological University (NTU) in Singapore
and stipends it offers to undergraduate students (internships) and
PhD students. I hope this will be of interest to faculty members
who would like to collaborate with Singapore's scientists as well
as students who would like to pursue their postgraduate career at
NTU.
Chair: Prof. Antoni Wójcik
/224/
Date: Wednesday 2014.11.26, 12:00
Speaker: Dr Tomasz Paterek
Affiliations:
1. Division of Physics and Applied Physics, School
of Physical and Mathematical Sciences, Nanynag Technological
University, Singapore
2. Centre for Quantum Technologies,
National University of Singapore
Title: Quantum biology
Abstract: With growing evidence of quantum effects in more and
more complex systems it becomes legitimate to ask if alive matter
can be influenced or take advantage of quantum features. Such
questions are studied in a newly emerging field of quantum
biology. Two examples will be discussed in more detail where
quantum coherence may play a role to speed up biologically
relevant process (photosynthesis) or even enable it
(magneto-reception). Finally, I will describe our planned
experiments on insects and how they are related to quantum
biology.
/223/
Date: Thursday 2014.10.23
Speaker: Dr Jacek Gąsiorowski
Affiliation: Semiconductor Physics, Technische Univeristät
Chemnitz, 09107 Chemnitz, Germany
Title: Organic semiconductors - from light harvesting to solar
fuels
Abstract: During the past two decades thin film photovoltaic cells
based on solution processable organic semiconductors attracted
much attention as possible cheap energy harvesting systems. They
are envisaged as feasible alternative to conventional inorganic
technologies. One great advantage of the organic photovoltaic is
that their morphological and photophysical properties can be
easily modified by tailoring the molecular structure. Therefore, a
great effort is made for the synthesis and characterization of new
organic materials, small molecules and polymers. Another big
advantage of the organic semiconductors is their mechanical
flexibility. Optimisation of the polymer molecules from the
fundamental core of this push-pull polymer have since gone on to
produce single junction organic photovoltaic device with power
conversion efficiency of 9%. The rapid increase in the light
harvesting efficiency was also followed by the approaches in using
solar energy for application in chemical reduction. Here, a
particularly interesting approach is to use solar energy for the
chemical and electrochemical reduction of CO2 to hydrocarbons
as well as for the artificial photosynthesis.
Chair: Prof. Małgorzata Śliwińska-Bartkowiak
/222/
Date: Thursday 2014.10.23
Speaker: Prof. Dr Georgeta Salvan
Affiliation: Semiconductor Physics, Technische Univeristät
Chemnitz, 09107 Chemnitz, Germany
Title: Magneto-optical Kerr Effect Spectroscopy of
Organic/Ferromagnetic Heterostructures
Abstract: Phthalocyanines and porphyrins find nowadays a variety
of applications from pigments to organic electronics and, more
recently, spintronics. This diversity of application potential
stems from the large flexibility of their molecular structure. We
focus on the room temperature magneto-optical activity of
phthalocyanines and porphyrins deposited on ferromagnetic
substrates (Co, Ni, and LSMO) as model heterostructures for
organic spintronics. The magnetic properties of the
heterostructures are assessed by magneto-optical Kerr effect
(MOKE) magnetometry. Variable angle spectroscopic ellipsometry
(VASE) in combination with MOKE spectroscopy investigations are
performed to extract the (magneto-) optical properties of the
heterostructures. From the degree of anisotropy of the optical
constants the molecular orientation can be determined. This allows
to systematically investigate the influence of the substrate
magnetization direction onto the molecular arrangement.
Chair: Prof. Małgorzata Śliwińska-Bartkowiak
/221/
Date: Wednesday 2014.10.8, 12:00
Speaker: M.Sc. Michał Mruczkiewicz
Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
Title: Particular Properties of Spin Waves in Magnonic Crystals:
Negative Refractive Index, Nonreciprocity and Damping
Abstract: I am presenting the results of investigation of spin
wave properties in periodic ferromagnetic structures
(one-dimensional magnonic crystals). The main attention of
research was put on development of numerical methods and analysis
of spin waves properties that are important for designing a
functional device. Three subjects of spin waves properties were
studied and they can be classified as: i) influence of damping on
standing spin wave formation ii) metamaterial properties for
electromagnetic waves propagating through magnonic crystal and
iii) nonreciprocal dispersion of spin waves. In particular I have
shown the analysis of the influence of the damping factor on the
spectrum of ferromagnetic resonance, the influence of metallic
overlayer on the damping, influence of structural parameters of
magnonic crystals on the magnetic permeability function of
metamaterial based on the crystal. I have also presented a
detailed analysis of symmetry breaking of the dispersion relation
of spin waves propagating in the ferromagnetic films in contact
with metal. The numerical calculation were confronted with
measured data, when available, and agreement between them was
shown.
Chair: Prof. Maciej Krawczyk
/220/
Date: Monday 2014.09.1
Speaker: Dr Bartłomiej Graczykowski
Affiliation: Phononic and Photonic Nanostructures Group, Catalan
Institute of Nanotechnology and Nanoscience (ICN2), Campus de la
UAB - Edifici ICN2, 08193-Bellaterra (Barcelona), Spain
Title: Acoustic phonon propagation in Si membranes and
nanostructures
Abstract: Studies on the phonon engineering have been gaining
importance in recent 20 yr. Previous research has shown that
phonon dispersion relation can be significantly modified by means
of phononic crystals (PnCs) [1-3], spatial confinement [4-5], or
external stress field [6-7]. Phononic crystals are in general
materials with one- (1D), two-, or three-dimensional periodicity
in their elastic properties. PnCs exhibit the modification of the
phonon dispersion and possible complete frequency band gaps due to
Bragg reflections or/and local resonances, which can be controlled
by geometry and material properties. Another approach to modify
the phonon dispersion relies on spatial confinement. Here, the
dynamic behaviour at reduced characteristic dimensions has been
found to be completely different than for bulk materials. I will
report on experimental (Brillouin light scattering) and
theoretical (finite element method) evidence of both phononic
properties (zone folding, band gap and local resonance) and phonon
confinement in one-dimensional Si surface PnCs and two-dimensional
Si membrane based PnCs. Additionally, I will discuss the influence
of the phononic patterning and phonon confinement on thermal
properties (Raman thermometry) and potential applications of PnCs
in thermoelectric devices.
[1] N. Gomopoulos, D. Maschke, C. Y. Koh, E. L. Thomas, W. Tremel, H.-J. Butt, and G. Fytas, Nano Lett. 10, 980 (2010).
[2] B. Graczykowski, S. Mielcarek, A. Trzaskowska, J. Sarkar, P. Hakonen, and B. Mroz, Phys. Rev. B 86, 085426 (2012).
[3] B. Graczykowski, M. Śledzińska, N. Kehagias, F. Alzina, J. S. Reparaz, C. M. Sotomayor Torres, APL 104, 123108 (2014).
[4] V. A. Fonoberov and A. A. Balandin, Nano Lett. 5, 1920 (2005).
[5] J. Cuffe, E. Chvez, A. Shchepetov, P.-O. Chapuis, E. H. El Boudouti, F. Alzina, T. Kehoe, J. Gomis-Bresco, D. Dudek, Y. Pennec, B. Djafari-Rouhani, M. Prunnila, J. Ahopelto, and C. M. Sotomayor Torres, Nano Lett. 12, 3569 (2012).
[6] A. Alofi and G. P. Srivastava, Phys. Rev. B 87, 115421 (2013).
[7] B. Graczykowski, J. Gomis-Bresco, F. Alzina, J. S. Reparaz, A.
Shchepetov, M. Prunnila, J. Ahopelto, C.M. Sotomayor Torres, New
J. Phys. 16, 073024 (2014).
Chair: Prof. Maciej Krawczyk
/219/
Date: Wednesday 2014.07.02
Speaker: Prof. Maciej Kozak
Title: Time-resolved SAXS studies of human cystatin C - first
observation of radiation induced domain swapping
Authors: Maciej Kozak1, Michał Taube1, Magdalena
Murawska1, Aneta Szymanska2, Anders Grubb3
1Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
2Department of Medicinal Chemistry, Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
3Department of Clinical Chemistry, Lund University, Lund,
Sweden
Abstract: Damaging effects of synchrotron radiation were observed
for the wide range of biological samples, ranging from protein
crystals to biological cells and tissues [1,2]. Most often these
damages were manifested as radiolysis of the tested molecules.
However, so far were not observed any conformational changes (such
as domain swapping) in the protein structures induced by the
synchrotron radiation.
The aim of this study was to observe the early stages of
dimerization of human cystatin C (HCC) via the domain swapping
mechanism. The time-resolved small angle scattering experiments
were performed using synchrotron radiation on P12 BioSAXS beam
line with very short acquisition time (50 ms) at PETRA III
synchrotron (DESY Hamburg). Solution scattering data were
subjected to detailed analysis by using SVD methods and MCR-ALS as
well as the shape determination. Besides the monomeric forms of
human cystatin C, also fractions of dimers and higher oligomeric
forms of HCC formed even after 50-ms exposure were identified. In
addition we showed directly for first time that the formation of
human cystatin C oligomers and fibryls was directly preceded by
the formation of domain swapped dimer.
[1] Borek, D.; Dauter, Z.; Otwinowski, Z. (2013) J. Synchr. Rad. 20, 37-48.
[2] Chen, Heyu; He, Xin; Sheng, Caibin; Ma, Yingxin; Nie, Hui;
Xia, Weiliang; Ying, Weihai (2011) Int. J. Physiol. Patophysiol.
Pharmacol. 3, 243-248.
Chair: Prof. Michał Banaszak
/218/
Date: Tuesday 2014.07.01
Speaker: Prof. Maciej Radosz
Affiliation: Soft Materials Laboratory, University of Wyoming,
U.S.A.
Title: Multiblock micelle and dendrimer carriers for cancer drugs
Abstract: Toxic hydrophobic drugs can be delivered to cancer
tissue using benign nano-sized carriers made of block copolymers,
dendrimers, or dendrimer-in-liposome particles. Polymeric carriers
prepared via micellization in non-aqueous near-critical solvents,
referred to as Near-Critical Micellization, have been demonstrated
to lead to a much higher drug loading, by as much as a factor of
three and to inhibit its premature release. This will be
illustrated with examples for PEG-b-PLLA-b-PCL nanoparticles
loaded with a model cancer drug paclitaxel. Such triblock
nanoparticles are found to be not only solvent-free and
paclitaxel-rich, which reduces the body exposure to the
excipients, but also nearly burst-release-free, which enhances
their therapeutic efficacy. Dendrimer-in-liposome carriers, in
turn, provide a unique opportunity to address two other, seemingly
contradictory drug-delivery requirements, namely a large size and
hence good stability while in circulation but small size and hence
rapid diffusion while penetrating the tumor tissue.
Chair: Prof. UAM Michał Banaszak
/217/
Date: Wednesday 2014.06.18
Speaker: Dr Artur Barasiński
Affiliation: Institute of Physics, University of Zielona Góra
Title: Generation of maximally entangled states in optical
supperlattices
Abstract: We discuss a model with ultra-cold atoms confined in
optical superlattices. In particular, we study the ground-state
properties of our system. Applying model involving spin-1 bosons
trapped in a double-well potential, we quantify the bipartite
entanglement between particles. Depending on the external magnetic
field and biquadratic interactions different phases of magnetic
order are realized and hence, various phases of the system's
entanglement. We show that changing the values of the parameters
determining superlattices, we can switch the system among various
maximally entangled states. What is important, our model seems to
be a good candidate for practical realization of the device which
can be a switchable tool for generation on demand of such a
states.
[1] A. Barasiński, W. Leoński, T. Sowiński, to appear in JOSA B
(2014).
Chair: Prof. UAM Adam Miranowicz
/216/
Date: Wednesday 2014.06.11
Speakers: Prof. Bogusław Mróz and M.Sc. Piotr
Graczyk
Affiliation: Zakład Fizyki Kryształów, WF UAM
Title: On the strong elasto-magnetic coupling in ferromagnetic
thin film sputtered onto ferroelastic substrate
Abstract: The influence of substrate ferroelastic phase transition
on the magnetization of ferromagnetic thin film was investigated.
Two different ferroic materials have been used:
ferroelastic/ferroelectric Gd2(MoO4)2 and pure
ferroelastic LiCsSO4 as a substrates. A nickel and permalloy
thin films, with the different thickness from 10 to 100 nm were
used.
Our measurements showed strong magnetization change at Curie
point, which reflect the temperature changes of spontaneous
deformation of the samples.
A strain-driven spin reorientation transitions were described
theoretically using a magnetic domain theory. It was shown that
magnetization reorientations occurs due to magnetoelastic
contribution to free energy and thus affect total magnetization
value of a sample. Results of our simulations were found to be in
good agreement with the experiments.
The preliminary results of Brillouin scattering on spin waves
propagating in our samples will be shown.
Chair: Prof. UAM Maciej Krawczyk
/215/
Date: Wednesday 2014.06.11
Speaker: Dr Mieczysław Torchała
Affiliation: Biomolecular Modelling Laboratory, Cancer Research UK
London Research Institute, 44 Lincoln’s Inn Fields, London WC2A
3LY, UK
Title: Studying protein-protein binding funnels with SwarmDock
Server and RaTrav
Abstract: Protein-protein interactions drive many of the
biological functions of the cell. Any two proteins have the
potential to interact; however, whether the interactions are of
biological significance is dependent on a number of complicated
factors. Thus, modelling the three-dimensional structure of
protein-protein complexes is still considered to be a complex
endeavour. In addition to correct protein-protein complex 3D
structure returned by the algorithm, equally important is dynamics
of binding, i.e., how proteins find their binding partners in the
multidimensional space of conformational transitions and how their
binding partners, upon complex formation, sample binding funnels,
i.e. what is the structure of conformational states space and in
which manner proteins change their conformations when traversing
this network. We recently released two freely available tools:
SwarmDock Server (a web service for the flexible modelling of
protein-protein complexes) [1] and RaTrav (a tool for calculating
mean first-passage times) [2]. In this talk we share our
experience related to conformational state network generation, its
structure and dynamics. We successfully applied occupancy
probabilities to distinguish between false positive and true
positive protein-protein binding funnels [3]and mean first-passage
times to find the favourable path and limiting transitions in the
true positive protein-protein binding funnel [2].
[1] M. Torchala, I.H. Moal, R.A.G. Chaleil, J. Fernandez-Recio,
P.A. Bates, 'SwarmDock: a
server for flexible protein-protein docking', Bioinformatics 29, 807-809 (2013).
[2] M. Torchala, P. Chelminiak, M. Kurzynski, P.A. Bates, 'RaTrav:
a tool for calculating mean
first-passage times on biochemical networks', BMC Syst. Biol. 7, 130 (2013).
[3] M. Torchala, I.H. Moal, R.A.G. Chaleil, R. Agius, P.A. Bates,
'A Markov-chain model description of binding funnels to enhance
the ranking of docked solutions', Proteins: Structure, Function,
and Bioinformatics 81, 2143-2149 (2013).
Chair: dr Przemysław Chełminiak
/214/
Date: Tuesday 2014.06.10
Speaker: M.Sc. Mikołaj Lasota
Affiliation: Faculty of Physics, Astronomy and Applied
Informatics, Nicolaus Copernicus University, Toruń
Title: Elementary linear optics quantum repeater links with
realistic single photon sources
Abstract: I study operation of realistic elementary quantum
repeater links constructed using multiple single photon sources,
quantum memories, linear optics, and heralding detectors. Two
schemes are considered. The first one is the well established
one-photon scheme which produces a photon in a delocalized
superposition state between two quantum repeater nodes, each of
them fed with one single photon at the input. The second one is a
linear optics analog of the robust scheme based on interfering two
Stokes photons emitted by atomic ensembles, which does not require
phase stability between the repeater nodes. Imperfect photon
sources are assumed, generating outputs with both vacuum and
multiphoton contributions. I find conditions for the source photon
statistics that guarantee generation of entanglement in the
relevant qubit subspaces and compare it with classicality
criteria. I also quantify the amount of entanglement that can be
produced with imperfect single photon sources, optimized over
setup parameters, using as a measure entanglement of formation.
Finally, I discuss verification of the generated entanglement by
testing Bell's inequalities.
Chair: Prof. UAM Adam Miranowicz
/213/
Date: Monday 2013.06.09
Speaker: Prof. Keith E. Gubbins
Affiliation: Department of Chemical & Biomolecular Engineering,
North Carolina State University, Raleigh, NC 27695-7905, U.S.A.
Title: Wetting at the Nano-Scale
Abstract: At the macro-scale the extent to which a liquid wets a
solid substrate is usually described in terms of the contact
angle, θc, and the surface tensions involved. Depending on
the liquid and substrate, the system is described as amphiphilic
('wetting', θc < 90o) or amphiphobic ('non-wetting',
θc > 90o). Such a description has a number of limitations;
in particular, it breaks down for sufficiently small nano-scale
systems, and is limited to describing liquid, as opposed to
gaseous or solid, adsorbed films. At a more fundamental level,
wetting is determined by the competition between the
adsorbate-substrate intermolecular forces and the
adsorbate-adsorbate forces. Through a corresponding states
analysis of the statistical mechanical description of such wetting
systems it is possible to define a microscopic wetting parameter,
aw, that is a measure of wetting that applies at all scales and
for any kind of adsorbed film (gas, liquid or solid) [1,2].
We illustrate the usefulness of this wetting parameter by
considering the properties of a nano-phase confined within a
porous material. In this case the dimensionless pore width, pore
shape and wetting characteristics of the confined phase are of
particular importance. Examples drawn from both experiment and
molecular simulation studies will be presented for phase
separations, selective adsorption in the case of mixtures, and
pressure enhancement, with emphasis on simple pore geometries.
These examples illustrate the central role played by wetting, and
also the breakdown of some concepts and macroscopic laws, such as
Gibbs' surface thermodynamics for nano-phases confined within
small pores.
[1] R. Radhakrishnan, K.E. Gubbins and M. Śliwińska-Bartkowiak,
"Global Phase Diagrams for Freezing in Porous Media", Journal of
Chemical Physics, 116, 1147-1155
(2002).
[2] Keith E. Gubbins, Yun Long and Małgorzata
Śliwińska-Bartkowiak, "Thermodynamics of Confined Nano-Phases",
Journal of Chemical Thermodynamics, 74, 169-183 (2014).
Chair: Prof. Małgorzata Śliwińska-Bartkowiak
/212/
Date: Wednesday 2014.06.4
Speaker: Dr Mirosław Łabuz
Affiliation: Department of Theoretical Physics, Faculty of
Mathematics and Natural Sciences, University of Rzeszów, Pigonia
1, 35-310 Rzeszów
Title: String hypothesis for short Heisenberg magnets
Abstract: It is well known, that exact Bethe Ansatz solutions for
the Heisenberg eigenproblem of a linear magnetic chain base upon
the hypothesis of strings. This hypothesis is presumed to work in
the thermodynamic limit N→∞, but it works pretty
well also in the finite case. I present some details of analysis
performed for short magnetic chains. In particular, I exploit
Galois symmetry associated with the secular eigenproblem in
determining rigged string configurations.
Chair: Prof. UAM Adam Miranowicz
/211/
Date: Thursday 2014.05.29
Speaker: B.Sc. Justyna Łodyga
Affiliation: Zakład Elektroniki Kwantowej, WF UAM
Title: Simple single-shot protocol for encoding and decoding an
unknown qubit state into various topological codes
Abstract: I present a general scheme for encoding and decoding an
unknown qubit state into various topological codes for quantum
error correction. I illustrate this method by means of Kitaev
planar code, where qubits are arranged in a two-dimensional array
on a surface of nontrivial topology. I also show that in the noisy
scenario (when state preparation and measurements are faulty) an
analytical bound for the fidelity of a quantum communication can
be easily provided following the scheme and is of order of noise
acting on a single physical qubit, in a large code size limit.
Chair: Prof. UAM Adam Miranowicz
/210/
Date: Wednesday 2014.05.28
Speaker: B.Sc. Justyna Łodyga
Affiliation: Zakład Elektroniki Kwantowej, WF UAM
Title: Introduction to quantum error correction codes
Abstract: Protecting quantum information from errors due to
decoherence and other quantum noise is crucial for fault-tolerant
quantum computation. In order to do quantum information processing
reliably in the presence of noise, the theory of error-correcting
codes has been developed. These codes work by encoding quantum
states in a special way that make them resilient against the
effects of noise, and then decoding when it is wished to recover
the original state. I start my presentation with comprehensive
introduction to quantum error correction theory. Then, I carry on
with short description of topological quantum error-correcting
codes, an important class of quantum codes.
Chair: Prof. UAM Adam Miranowicz
/209/
Date: Thursday 2014.05.22
Speaker: Dr Andrii Chumak
Affiliation: Fachbereich Physik and Forschungszentrum OPTIMAS,
Technische Universität Kaiserslautern, 67663 Kaiserslautern,
Germany
Title: Magnons as an alternative to a charge current
Abstract: With conventional CMOS technology data is carried by
flows of electrons that generate heat which is responsible for the
device's power consumption. An alternative to this principle is
the employment of other particles or quasi-particles as
information carriers which are subject to dissipation to a lesser
degree than electrons. I will show that eigen excitations of
magnetic media - magnons can be used for this role.
In my talk, after an introduction on spin waves and their quanta
magnons, I will concentrate on the artificial magnetic materials
with periodically-modulated magnetic properties - magnonic
crystals. Several different designs of macro- and micro-scaled
magnonic crystals will be discussed [1-3]. In the second part of
the talk, the magnon-based data processing elements will be shown:
time reverser of microwave pulses [4] and magnon transistor. These
proof of concept devices are made out of an insulator in order to
exclude any motion of free electrons and are based on magnonic
crystals. The time reverser is based on a dynamic magnonic
crystal: a crystal with properties that can be varied using
external controls on a very fast time scale. We have shown that a
wave packet, while being reflected by the dynamic crystal,
reverses its time profile [4]. The magnon transistor is the device
operational principle of which is based on the control of magnons
by magnons. It was realized through an enhancement of nonlinear
magnon interactions in a magnonic crystal. We have shown that the
transistor allows for the design of all-magnon logic gates as well
as for enhancement of magnonic signals. The final part of the talk
will be devoted to the miniaturization issues of the
insulator-based magnonics. Very recently we have studied spin-wave
excitation and propagation in an insulator yttrium-iron-garnet
spin-wave waveguide of micrometer sizes [5]. These results
represent a valid step towards the nano-scaled particle-less
technology in which information is carried and processed by
magnons rather than by electrons.
[1] A.V. Chumak, et al., Phys. Rev. Lett. 108, 257207 (2012).
[2] A.V. Chumak, et al., Appl. Phys. Lett. 95, 262508 (2009).
[3] B. Obry, et al., Appl. Phys. Lett. 102, 202403 (2013).
[4] A.V. Chumak, et al., Nat. Commun. 1:141 doi:
10.1038/ncomms1142 (2010).
[5] P. Pirro, et al., Appl. Phys.
Lett. 104, 012402 (2014).
Chair: Prof. UAM Maciej Krawczyk
/208/
Date: Tuesday 2014.05.20
Speaker: Prof. Nobuyuki Imoto
Affiliation: Department of Materials Engineering Science, Graduate
School of Engineering Science, Osaka University, Osaka, Japan
Title: Two-state formalism
Abstract: A procedure to obtain the expectation value of an
arbitrary observable is referred to as "state." Usually, such
"state" has one-to-one correspondence to the quantum state of
the physical system. In some cases, however, we know not only the
prepared quantum state but also the post-selected state, which we
actually see. If we estimate the measurement result performed by
the third party intermediately, such mathematical "state"
contains two physical states: initial and final states. Sometimes,
we can precisely estimate the value of the conjugate observables
regardless with his/her choice [1]. The "state" of course
depends on the measurement, but the expression becomes simple for
the weak measurement and strong measurement. For the weak
measurement, it becomes the weak value [2], which exhibits
interesting properties in paradoxical situations [3,4].
[1] K. Shimizu, et. al.: Phys. Rev. A 84, 022308 (2011).
[2] Y. Aharonov, et. al.: Phys. Rev. Lett. 60, 1351 (1988).
[3] Y. Aharonov, et. al.: Phys. Lett. A 301, 130 (2002).
[4] J. S. Lundeen and A. M. Steinberg, Phys. Rev. Lett. 102, 020404 (2009);
K. Yokota et. al., New J. Phys. 11, 033011 (2009).
Chair: Prof. UAM Adam Miranowicz
/207/
Date: Thursday 2014.05.15
Speaker: Dr Karol Załęski
Affiliation: Centrum NanoBioMedyczne UAM
Title: Properties of magnetic Heusler alloys - experimental and
theoretical approach (part II)
Abstract: Heusler alloys are a class of materials with diverse
physical properties and many potential applications. Depending on
their specific composition they can exhibit half-metallic
ferromagnetism (full spin polarization at the Fermi level),
magnetic shape memory (martensitic transformation in a
ferromagnetic state), among others. The Heusler alloys Ni-Mn-Sn
belong to a family of magnetic shape memory alloys. This
magnetostructural transformation leads to magnetocaloric effect,
modification of exchange coupling, large magnetoresistance, etc.
The comprehensive experimental investigation of magnetic,
transport and structural properties of Ni-Mn-Sn thin films was
undertaken as well as ab initio calculations. It was shown that
the local atomic configuration affects on magnetic properties. The
estimated values of the martensitic transformation temperature and
Curie (Néel) temperature were collected in the form of phase
diagram.
Chair: Prof. UAM Maciej Krawczyk
/206/
Date: Wednesday 2014.05.14, 12:00
Speaker: Dr hab. Genowefa Ślósarek
Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM
Title: Denaturacja i agregacja białek (Denaturation and
aggregation of proteins)
Abstract: Z chwilą, gdy rozwinęły się badania nad przyczyną chorób
wywołanych przez amyloidy, rozbudowane zostały również badania
podstawowe dotyczące procesu agregacji białek. Wykazano szybko, że
proces agregacji występuje stosunkowo często i generalnie może to
być proces odwracalny (w niektórych przypadkach in vivo) lub
nieodwracalny (także w szczególnych przypadkach zmian
fizjologicznych). Powstające agregaty mają często formę
uporządkowanych, regularnych struktur. Wykazano także, że proces
agregacji ściśle wiąże się z denaturacją cząsteczek białkowych.
Chair: Prof. UAM Michał Banaszak
/205/
Date: Thursday 2014.05.8
Speaker: Dr Karol Załęski
Affiliation: Centrum NanoBioMedyczne UAM
Title: Properties of magnetic Heusler alloys - experimental and
theoretical approach (part I)
Abstract: Heusler alloys are a class of materials with diverse
physical properties and many potential applications. Depending on
their specific composition they can exhibit half-metallic
ferromagnetism (full spin polarization at the Fermi level),
magnetic shape memory (martensitic transformation in a
ferromagnetic state), among others. The Heusler alloys Ni-Mn-Sn
belong to a family of magnetic shape memory alloys. This
magnetostructural transformation leads to magnetocaloric effect,
modification of exchange coupling, large magnetoresistance, etc.
The comprehensive experimental investigation of magnetic,
transport and structural properties of Ni-Mn-Sn thin films was
undertaken as well as ab initio calculations. It was shown that
the local atomic configuration affects on magnetic properties. The
estimated values of the martensitic transformation temperature and
Curie (Néel) temperature were collected in the form of phase
diagram.
Chair: Prof. UAM Maciej Krawczyk
/204/
Date: Tuesday 2014.04.29, 12:00
Speaker: Prof. Robert Hołyst
Affiliation: Dyrektor Instytutu Chemii Fizycznej PAN w Warszawie
Title: Artificial and biological engines
Abstract: I will discuss two issues related to the performance of
artificial and biological engines. Three cases will be presented:
ferroelectric liquid crystal monolayer performing continuous
rotation in a monolayer of 3nm size powered by the flux of water;
ATP as a biological pump powered by the flux of protons and
finally kinesin motion along microtubules. In these three cases we
will discuss the power of such engines and their resistance to
thermal noise and local energy barriers induced by crowding by
linear polymers.
Chair: Prof. UAM Michał Banaszak
/203/
Date: Wednesday 2014.04.23, 12:00
Speaker: Dr hab. Jarosław S. Kłos
Affiliation: Zakład Fizyki Komputerowej, Wydział Fizyki UAM
Title: Simulations of neutral and charged dendrimers
Abstract: We study the properties of neutral and charged
dendrimers with flexible spacer-chains of various lengths and
explicit counterions using Monte Carlo simulations based on the
bond fluctuation model. For neutral dendrimers with the excluded
volume interactions our simulations confirm the theoretical
prediction for the scaling behavior of the dendrimer size. For
charged dendrimers the full Coulomb potential is taken into
account with the reduced temperature τ as the main control
parameter. Our simulations show an interplay of counterion
condensation, trapping of counterions inside the dendrimer's
volume and counterion evaporation into the solution which give
rise to a non-monotonous electrostatic swelling of the molecule
with τ. To explain the swelling effect we apply a Flory-type
argument where both trapped but non-condensed counterions and
uncompensated charges due to counterion evaporation are included.
This model properly reflects the swelling behavior with respect to
temperature, pH and spacer-length variation, though quantitatively
underestimates it.
Chair: Prof. UAM Adam Miranowicz
/202/
Date: Wednesday 2014.04.16
Speaker: Dr Maciej Misiorny
Affiliations: (1) Forschungszentrum Jülich, Peter Grünberg
Institut, Theoretical Nanoelectronics Division (PGI-2), 52425
Jülich, Germany and (2) Mesoscopic Physics Division, Physics
Faculty, AMU.
Title: Spintronic magnetic anisotropy
Abstract: Experimental techniques nowadays allow for detailed
transport measurements of individual atoms [1] or molecules [2,3]
that exhibit magnetic anisotropy. The superparamagnetism of these
systems, i.e. the preferential alignment of their spins along an
easy axis, is a useful effect for nanoscale applications as it
prevents undesired spin reversal. It has been suggested [4], and
also experimentally proven for magnetic atoms [5], that
spin-polarized currents can be employed to control the magnetic
state of such systems assuming a given, intrinsic anisotropy.
Furthermore, it has been also demonstrated that magnetic
anisotropy can play a major role in formation of the Kondo effect
in nanoscopic systems [1,3]. However, the spintronic transport
also changes the magnetic anisotropy that it tries to probe and
therefore these two cannot be treated separately. In fact, we have
recently shown that any spin-isotropic high-spin quantum dot
coupled to ferromagnets can acquire superparamagnetic properties
in a spintronic way, i.e. from the outside via an effective
quadrupolar exchange field [6]. The talk will review various
theoretical aspects of transport through nanoscopic systems
displaying magnetic anisotropy, with the main emphasis on how the
flow of spin-polarized current through such a molecule/adatom can
induce the magnetic anisotropy.
[1] A.F. Otte et al., Nature Phys. 4, 847 (2008).
[2] H.B.
Heersche et al., Phys. Rev. Lett. 96, 206801 (2006); A. Zyazin et
al., Nano Lett. 10, 3307 (2010); E. Burzuri et al., Phys. Rev.
Lett. 109, 147203 (2012).
[3] J.J. Parks et al., Science 328,
1370 (2010).
[4] M. Misiorny and J. Barnaś, Phys. Rev. B 75,
134425 (2007); Phys. Rev. Lett. 111, 046603 (2013).
[5] S.
Loth et al., Nature Phys. 6, 340 (2010).
[6] M. Misiorny, M.
Hell and M. Wegewijs, Nature Phys. 9, 801 (2013).
Chair: Prof. Adam Miranowicz
/201/
Date: Thursday 2014.04.10
Speaker: Prof. Jean-Claude S. Levy
Affiliation: Matériaux et Phénome`nes Quantiques, Université
Paris, France
Title: Magnetic structures of 2D/3D nanoparticles
Abstract: Magnetic nanoparticles have many applications, from
printing to medical treatments, electronic memories and radio
frequency devices, but their magnetic structure is still not well
known. After a short review of one century of observations of
magnetic domains in magnetic particles and magnetic nanoparticles
especially on 2D particles, comments will be given on last twenty
years of numerical simulations. A short review of the magnetic
dynamics of such particles and nanoparticles will also be given.
Then analytic considerations on magnetic structures of 2D and 3D
nanoparticles will be reported as well as basic models for the
magnetic structure of small enough nanoparticles. Finally recent
numerical results on the magnetic structure of 2D and 3D
nanoparticles and their dynamics will be given.
Chair: Prof. UAM Maciej Krawczyk
/200/
Date: Tuesday 2014.04.8
Speaker: Prof. Yuri Gorobets
Affiliation: Institute of Magnetism, National Academy of Sciences
of Ukraine, Kiev, Ukraine
Title: Biogenic nanomagnetism
Abstract: The lecture contains the review of the experimental data
about the biogenic magnetic nanoparticles (BMNs) in different
organisms. The BMNs became the object of intensive research since
1975 when the BMNs were detected in magnetotactic bacteria (MTB)
for the first time. The literature data about the proteins of the
so-called magnetosome island of MTB will be represented concerning
the process of biomineralization of BMNs. The physiological origin
of BMNs, their possible functions in multi-cellular organisms and
interrelation with the number of human diseases will be considered
on the basis of the bioinformatics methods and magnetochemical
effects.
Chair: Prof. UAM Maciej Krawczyk
/199/
Date: Wednesday 2014.04.2
Speaker: Dr Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Efficient Amplification of Photonic Qubits by Optimal
Quantum Cloning
Abstract: We demonstrate a phase-independent quantum amplifier of
a polarization qubit which can outperform the heralded qubit
amplifier [S. Kocsis et al., Nature Physics 9, 23 (2013)]. It
employs the multi-functional cloner in 1 to 2 copying regime,
capable of providing approximate copies of qubits given by various
probability distributions, and is optimized for distributions with
axial symmetry. The direct application of the proposed solution is
possible in quantum technologies, doubling the range where quantum
information is coherently broadcast. It also outperforms natural
nonlinear amplifiers that use stimulated emission in bulk
nonlinear materials. We consider the amplifier to be an important
tool for amplifying quantum information sent via quantum channels
with phase-independent damping.
Chair: Prof. UAM Adam Miranowicz
/198/
Date: Wednesday 2014.03.26
Speaker: Dr Krzysztof Dobek
Affiliation: Quantum Electronics Division, Faculty of Physics, AMU
Title: New approaches in tunable optics
Abstract: During the talk I will present modern techniques that
allow to actively controlling the optical properties of a single
optical element e.g. the lens focal length. First I will show
widely used macroscopic devices, used for instance in astronomy,
then emerging microscopic devices developed recently. Finally, I
will present our efforts in the development of a flexible focal
length device, whose operation is based on a new thermo-optical
technique.
Chair: Prof. UAM Adam Miranowicz
/197/
Date: Wednesday 2013.03.19
Speaker: Prof. Mirosław Dudek
Affiliation: Institute of Physics, University of Zielona Góra
Title: Mean field method with space dependent order parameter
Abstract: A new and efficient algorithm for the mean-field
approximation is presented, in which we do not need to solve
explicitly the self-consistent condition. This algorithm is a
modification of the Metropolis algorithm which is often used in
Monte Carlo simulations.
Chair: Prof. UAM Michał Banaszak
/196/
Date: Wednesday 2014.03.12
Speaker: Prof. Michał Banaszak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: From Fractal Chaos to Regular Patterns and Vice Versa.
Self-Organisation in Spatial Systems
Abstract: This study offers a new perspective on the spatial
impacts generated by cities or urban agglomerations. These impacts
can range from chaotic to fully ordered. We demonstrate that
cities produce a wealth of gravitational attractors whose size and
shape depend on the resistance of space emerging inter alia from
transport friction costs. This finding offers original insights
into the complex evolution of spatial systems and appears to be
consistent with the principles of central place theory known from
spatial sciences and geography. Our approach is dynamic in nature
and forms a generalization of hierarchical principles in
geographic space.
Chair: Prof. UAM Maciej Krawczyk
/195/
Date: Wednesday 2014.03.5
Speaker: Prof. Grzegorz Pawłowski
Affiliation: Zakład Stanów Elektronowych Ciała Stałego, WF UAM
Title: Zastosowanie środowiska ALPS (2.1) do obliczeń w układach
silnie skorelowanych
Abstract: W ramach wykładu zaprezentowana zostanie najnowsza
wersja 2.1.1 środowiska Algorithms and Libraries for Physics
Simulations (ALPS) [1] wraz z jego zastosowaniami. ALPS jest
projektem typu open source rozwijanym od roku 2004 przez
międzynarodową grupę fizyków teoretyków specjalizujących się w
badaniu układów silnie skorelowanych [2].
Wszystkie elementy pakietu wykorzystują wspólny format danych
zapisanych w języku XML. Na tym poziomie przeprowadzenie symulacji
nie wymaga znajomości programowania w języku C++, w jakim zostały
napisane biblioteki obliczeniowe i główne aplikacje.
Gotowe programy obejmują implementacje najważniejszych algorytmów
dla modeli kwantowych na sieci, jak np.: klasyczne i kwantowe
Monte Carlo (spinMC, QMC) w wersji lokalnej i klasterowej,
kwantowe symulacje typu Wanga-Landaua (QWL), dokładna i pełne
diagonalizacja (ED), macierz gęstości grupy renormalizacji (DMRG)
czy dynamiczne pole średnie (DMFT).
Zawarte w projekcie biblioteki stanowią ramy do rozwoju własnego
oprogramowania z wykorzystaniem obliczeń równoległych typu openMPI
na różnych platformach sprzętowych i systemowych.
W nowej wersji 2 oprogramowania ALPS uwzględniono wykorzystanie
standardu HDF5 do zapisu i zarządzania danymi, użycie
specjalistycznych narządzi do analizy wyników napisanych w języku
Python oraz integrację pracy całego systemu w środowisku do
wizualizacji procesów obliczeniowych VisTrails.
Wykład uzupełniony będzie o liczne przykładowe obliczenia.
[1] http://alps.comp-phys.org;
[2] B.Bauer et al. (ALPS collaboration), "The ALPS project release
2.0: open source software for strongly correlated systems",
J.Stat.Mech. P05001 (2011).
Chair: Prof. UAM Michał Banaszak
/194/
Date: Thursday 2014.02.27
Speaker: Dr Ryszard Gieniusz
Affiliation: Uniwersytet w Białymstoku
Title: Fale spinowe w strukturyzowanych warstwach granatów
Abstract: Przedstawione zostaną wybrane efekty zachowania się fal
spinowych w strukturyzowanych warstwach granatu itrowo-żelazowego.
Omówione będzie oddziaływania fal spinowych z: (i) pojedynczym
otworem - zjawisko dyfrakcji fal spinowych; (ii) linią otworów -
efekt całkowitego wewnętrznego odbicia tych fal; (iii)
dwuwymiarową sieci otworów. Badania wykonano z wykorzystaniem: (i)
klasycznego spektrometru nieelastycznego rozpraszania światła
Brillouina (BLS) z rozdzielczością czasową i przestrzenną w
konfiguracji odbiciowej i transmisyjnej, (ii) mikroskopu BLS
pracującego w konfiguracji odbiciowej z rozdzielczością
przestrzenną do ok. 300 nm; (iii) spektrometru FMR. Wyniki
eksperymentalne interpretowano korzystając między innymi z
modelowania mikromagnetycznego. Dodatkowo przedstawione będą,
planowane do dalszych badań, nowe struktury magnoniczne w oparciu
o naświetlane jonami magnetyczne nanostruktury.
Chair: Prof. UAM Maciej Krawczyk
/193/
Date: Wednesday 2014.02.26 at 13:00
Speaker: Prof. Dagomir Kaszlikowski
Affiliation: Centre for Quantum Technologies, National University
of Singapore
Title: The triangle principle: new approach to non-classical
correlations
Abstract: We study an application of an information-theoretic
distance between two measurements to investigate non-classical
correlations. We postulate the triangle principle, which states
that any information-theoretic distance is well defined on any
pair of measurements, even if these measurements cannot be jointly
performed. As a consequence, the triangle inequality for this
distance is obeyed for any three measurements. This simple
principle is valid in any classical realistic theory, however it
may not hold in quantum theory. It leads to derivation of certain
inequalities whose violations are indicators of non-classicality.
Some of these inequalities formally look the same as those found
in the literature on local realism and non-contextuality but we
also derive completely new inequalities. We also show that our
geometrical approach naturally implies monogamy of non-classical
correlations.
Chair: Prof. UAM Maciej Krawczyk
/192/
Date: Monday 2014.02.24
Speaker: Prof. Peter Nijkamp
Affiliation: Professor of Regional Economics and Economic
Geography at the Vrije Universiteit, Amsterdam, the Netherlands, a
fellow of the Tinbergen Institute and President of the Governing
Board of the Netherlands Research Council (NWO).
Title: Virtual reality: The death of distance revisited.
Chair: Prof. UAM Michał Banaszak
/191/
Date: Wednesday 2014.02.19
Speaker: Dr Paweł Kurzyński
Affiliation: Centre for Quantum Technologies, National University
of Singapore and Faculty of Physics, Adam Mickiewicz University
Title: How to test indistinguishability of particles
Abstract: My talk will consist of two parts. First, we propose a
test to measure the bosonic and fermionic quality of particles
with respect to physical operations of single-particle addition
and subtraction. We apply our test to investigate bosonic
properties of composite particles made of an even number of
fermions and suggest its experimental implementation. Next, we
show that under certain assumptions one can derive a variant of
Specker's non-contextual inequality for a system of three
indistinguishable bosonic particles. The inequality states that
the sum of probabilities of three pairwise exclusive events is
bounded by one. This inequality cannot be violated using standard
quantum mechanical projectors and cannot be violated by
independent distinguishable particles. On the other hand, due to
bosonic properties this bound is violated up to 3/2. We also argue
that the violation of this inequality can be considered as a test
of bosonic nature.
/190/
Date: Wednesday 2014.02.12
Speaker: Prof. Jacek Gapiński
Coauthors: Prof. Adam Patkowski and Prof. Gerhard Naegele
Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM
Title: Struktura, dynamika i krystalizacja układów koloidalnych
typu Yukawy. Część II.
(Structure, dynamics and crystallization
of Yukawa type colloidal systems. Part II.)
Abstract: In the preceding talk, prof. Adam Patkowski explained
the methods and tools which have been used to calculate the pair
correlation function g(r) and the structure factor S(q) of
colloidal systems with Yukawa-type interactions. Using these tools
we managed to calculate the freezing lines of such systems both
using experimentally measurable parameters and generalized
parameters. In the latter case a master curve was obtained. In
this part I am going to discuss the information accessible from
the pair correlation function g(r) which describes the local
structure of colloidal systems. In particular, I will show such
parameters as the number of nearest neighbors, mean nearest
neighbor distance, position of the maximum of g(r), and peak
position of S(q). Conclusions drawn from the values obtained at
freezing lines will be extended to colloidal systems in fluid
state, leading to surprising results concerning the local
structure of strongly interacting colloids.
/189/
Date: Wednesday 2014.02.5
Speaker: Prof. Adam Patkowski
Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM
oraz Centrum NanoBioMedyczne UAM
Title: Struktura, dynamika i krystalizacja układów koloidalnych
typu Yukawy. Część I.
(Structure, dynamics and crystallization of
Yukawa type colloidal systems. Part I.)
Abstract: Oddziaływania w zawiesinach naładowanych koloidów
opisane są przez efektywną energię oddziaływań dwójkowych typu
Yukawy: u(r)/kBT ∼ AZ2exp(−κr)/r, gdzie A jest
stałą układu, κ−1 - długością ekranowania Debye'a, Z -
efektywnym ładunkiem cząstki. Uporządkowanie bliskiego zasięgu w
układach koloidalnych może być mierzone przy pomocy: dwójkowej
funkcji rozkładu radialnego g(r), średniej odległości
najbliższych sąsiadów rn i ich liczby Nn. Ostatnie dwie
wielkości mogą być obliczone z funkcji g(r). Uporządkowanie
dalekiego zasięgu w układach koloidalnych mierzone jest przez
zależny od wektora rozpraszania q statyczny czynnik struktury
S(q), który może być zmierzony w eksperymencie rozpraszania
światła lub nisko-kątowego rozpraszania promieni rentgena (SAXS).
Punkt krystalizacji układu koloidalnego dany jest przez kryterium
Hansena-Verleta (HV): S(qm)=3. Dynamika układu koloidalnego
charakteryzowana jest przez krótko-czasowy współczynnik dyfuzji
kolektywnej DC(q), określony jako: DC(q)=D0H(q)/S(q), gdzie
D0 jest wartością dla nieskończonego rozcieńczenia układu, a
H(q) jest zależną od q funkcją hydrodynamiczną. Wykazaliśmy,
przy pomocy statycznego (SAXS) i dynamicznego (XPCS) rozpraszania
rentgenowskiego promieniowania synchrotronowego, że modele
teoretyczne dla S(q) - równanie całkowe Rogersa-Younga (RY),
oraz dla DC(q)-model δγ, dobrze opisują dane
doświadczalne uzyskane dla naładowanych koloidów w całym zakresie
ciekłym [1]. Stosując model δγ przeanalizowaliśmy
zachowanie funkcji hydrodynamicznej H(q) [2], a przy pomocy
równania całkowego RY oraz kryterium HV uzyskaliśmy również krzywą
krystalizacji [3] dla naładowanych koloidów typu Yukawy w szerokim
zakresie ładunku, rozmiarów i stężenia koloidów i stężenia dodanej
soli. Ostatnio badaliśmy także punktu krystalizacji.
[1] J. Gapinski, A. Patkowski, A. J. Banchio, J. Buitenhuis, P.
Holmquist, M. P. Lettinga, G. Meier and G. Nägele, J. Chem. Phys.
130 (2009) 084503.
[2] J. Gapinski, A. Patkowski and G.
Nägele, J. Chem. Phys. 132 (2010) 054510.
[3] J. Gapinski, G.
Nägele, and A. Patkowski, J. Chem. Phys. 136 (2012) 024507.
/188/
Date: Wednesday 2014.01.29
Speaker: Dr Sławomir Mamica
Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
Title: Spin-wave spectra of two-dimensional circularly magnetized
nanodots and nanorings
Abstract: The properties of small magnetic dots are the object of
increased interest because of their rich physics and potential
applications in a variety of fields, such as data storage and
information processing, single magnetic nanoparticle sensing and
trapping, microwave-frequency oscillators, or frequency
multiplication. The physical phenomena observed in small magnetic
dots are related to their minute dimensions, ranging from tens of
nanometers to a few micrometers, and the competition between the
long-range dipolar interaction and the short-range exchange
interaction. In small magnetic dots their concurrence leads, among
other effects, to a rich spectrum of stable and metastable
magnetic configurations, including vortex states. The chirality
and polarity of the vortex are potential information carriers and
can be switched with external magnetic field, electric current, or
microwave radiation. An important role in magnetization switching,
as well as in the stability of magnetic configurations, is played
by spin-wave excitations. Moreover, the role of thermally excited
spin waves in magnetization switching proves very important even
in particles smaller than the exchange length.
In this work we use a microscopic theory taking into account the
dipolar and nearest-neighbour exchange interactions for exploring
spin-wave excitations in two-dimensional magnetic dots in the
vortex state. Normal modes of different profiles are observed:
azimuthal and radial modes, as well as fundamental (quasiuniform)
and highly localized modes. We examine the dependence of the
frequencies and profiles of these modes on the dipolar-to-exchange
interaction ratio and the size of the dot. Special attention is
paid to some particular modes, including the lowest mode in the
spectrum and the evolution of its profile, and the fundamental
mode, the frequency of which proves almost independent of the
dipolar-to-exchange interaction ratio. Finally, we study the
hybridization of the modes, show the multi-mode hybridization and
explain the selection rules.
[1] S. Mamica et al., J. Phys. D, accepted (2013).
[2] S.
Mamica, J. Appl. Phys., accepted (2014).
/187/
Date: Tuesday 2014.01.21
Speaker: Prof. Andrzej Sikorski
Affiliation: Zakład Teorii Biopolimerów, Wydział Chemii
Uniwersytetu Warszawskiego
Title: The properties of adsorbed polymers
Abstract: The properties of polymer films formed by adsorbed or
tethered chains are important for practical reasons (lubrication,
colloidal stabilization, chromatography etc.) and interesting from
the theoretical point of view. The adsorption of homo- and
copolymers on homogenous and patterned surfaces was a subject of
our studies. We employed computer simulations of idealized models
as a main tool. The coarse-grained models of macromolecules were
designed for this purpose. The properties of the system studied
were determined using some versions of the Monte Carlo method. The
influence of the temperature, the strength of the adsorption, the
sequence of mers, patterns on the surface and the macromolecular
architecture on the properties of chains were studied. The results
were discussed and compared to other simulations results,
theoretical predictions and real experiments.
/186/
Date: Wednesday 2014.01.15
Speaker: Dr Sławomir Mamica
Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
Title: Stability of the in-plane vortex state in two-dimensional
magnetic nanodots and nanorings
Abstract: A major scientific interest of magnetic nanodots and
nanorings lies in the concurrence of the exchange and dipolar
interactions. In a variety of systems, long-range interactions
have led to a number of interesting findings. However, the
concurrence of short-range and long-range interactions proves
particularly interesting. Also the magnetic vortex state stems
from the competition between the long-range dipolar interaction
and the short-range exchange interaction. On the other hand,
studies of the possible stable and metastable magnetic
configurations in magnetic nanorings are of major importance
regarding to the potential applications which extend from data
processing and high-density magnetic random access memory (MRAM)
elements to microwave frequency oscillators and single magnetic
nanoparticle sensors.
In this work we study two-dimensional nanodots and nanorings
composed of elementary magnetic moments arranged in sites of a
square lattice. Using a microscopic approach that takes into
account the dipolar and nearest-neighbour exchange interactions,
we calculate the spin-wave frequencies and profiles to draw
conclusions regarding the stability of the assumed magnetic
configuration. We show that, in contrast to square rings, in
circular rings the exchange-driven reorientation is sensitive to
both the external and internal sizes of the ring. We associate
this behaviour with the delocalized character of the lowest
spin-wave excitation, and show that, consequently, the in-plane
vortex state can be stabilized even in the case of strong exchange
interactions.
[1] S. Mamica et al., J. Nanopart. Res. 13, 6075 (2011).
[2] S. Mamica et al., J. Appl. Phys. 112, 043901 (2012).
[3] S. Mamica, J. Appl. Phys. 113, 093901 (2013).
/185/
Date: Wednesday 2014.01.08
Speaker: Dr Ewa Banachowicz
Affiliation: Zakład Biofizyki Molekularnej, Wydział Fizyki UAM
Title: Struktura przestrzenna zdenaturowanych białek badana
metodami Monte Carlo
Abstract: Struktura białek od dziesięcioleci stanowi przedmiot
dociekań naukowców z różnych dziedzin. Dzięki znajomości
przestrzennej budowy cząsteczek biologicznych łatwiej jest
przewidzieć i zrozumieć ich funkcję. We współczesnej farmacji
rozwiązanie struktury tak zwanego białka docelowego (targetu) jest
podstawą zaprojektowania skutecznego i specyficznie działającego
leku. Rozwinięto zatem wysokorozdzielcze techniki eksperymentalne
pozwalające z dokładnością do pojedynczego atomu określić
przestrzenne rozmieszczenie wszystkich jego elementów. Na tej
podstawie powstała hipoteza o uporządkowanej i stosunkowo sztywnej
budowie białek. Okazało się jednak, że pośród białek, którym
przypisano kluczową rolę w procesach biologicznych wiele posiada
budowę „wewnętrznie nieuporządkowaną”. Struktura białka
zdenaturowanego (rozplecionego w określonych warunkach), podobnie
jak struktura giętkich nieuporządkowanych wewnętrznie białek, nie
może być ustalona ani za pomocą rentgenografii strukturalnej ani
spektroskopii NMR. Zależność promienia bezwładności od masy oraz
czynnik kształtu otrzymywane z badań niskokątowego rozpraszania
neutronów i promieniowania rentgenowskiego dla roztworów tych
białek wskazują na strukturę kłębka statystycznego. Nie wyjaśniają
jednak w jaki sposób kłębek statystyczny może w specyficzny sposób
oddziaływać z innymi białkami, tworząc aktywne biologicznie
kompleksy. Nie jest też do końca jasne, w jaki sposób swobodny,
losowo ułożony łańcuch przechodzi do formy uporządkowanej.
Łańcuchy białkowe są polimerami o dość złożonej budowie. Każdy mer
jest jednym z 20 aminokwasów i może mieć inne własności fizyczne -
inny ładunek, objętość lub długość łańcucha bocznego - niż jego
sąsiad. Kolejność merów decyduje o lokalnych własnościach łańcucha
głównego i wyklucza pewne grupy konformacji. Symulacje Monte Carlo
swobodnie błądzącego łańcucha białkowego reprezentowanego przez
pełno-atomowy model w sieci FCC mają ułatwić odpowiedz na pytania:
(1) czy zdenaturowane i wewnętrznie nieuporządkowanie białka
rzeczywiście mają strukturę kłębka? (2) jak rozmiar łańcuchów
bocznych może wpłynąć na strukturę całej cząsteczki? oraz (3)
jakie oddziaływania determinują ewentualną strukturę lokalną?
/184/
Date: Tuesday 2013.12.17, 10:00
Speaker: Prof. Maciej Lewenstein
Affiliation: ICREA Research Professor at ICFO (Institut de
Cie`ncies Foto`niques), Barcelona, Spain.
Title: Report from the frontiers of atomic, molecular and optical
physics and quantum information
Abstract: In my lecture I will talk about some hot topics of AMO
and QI by presenting examples of several lines of research,
concentrating on theoretical and experimental challenges. The
particular subjects will include: a) quantum simulators, i.e.
systems capable of simulation of non-trivial and hard to treat
quantum many body problems; b) novel kind of numerical and
theoretical approaches to many body systems (tensor network
states), employing the role of entanglement in many body problems;
c) hybrid systems, combining nano-physics with quantum optics.
/183/
Date: Wednesday 2013.12.11
Speaker: Dr Sławomir Mamica
Affiliation: Zakład Fizyki Nanomateriałów, Wydział Fizyki UAM
Title: On the three-dimensional magnetoferritin-based magnonic
crystals. Perspectives for the magnonic band gap tailoring
Abstract: Magnetic nanoparticles (NPs) have been intensively
studied because of their unusual physical properties as well as
promising applications in a wide variety of fields that range from
medicine to nanoelectronics. In this study we consider the use of
biomimetic NPs of the very numerous magnetoferritin superfamily as
the basis for the realization of 3D magnonic crystals in which the
interparticle space is filled with a ferromagnetic material. The
use of protein cages as reaction chambers for the production of
NPs has a number of advantages. One of them is a high level of
homogeneity of the NPs in terms of size and shape, determined by
the internal surface of the protein cage. Another major advantage
of biomimetic NPs from the point of view of this study is the
possibility of producing highly ordered 3D structures by
self-assembly [1].
We use the plane wave method to demonstrate that the introduction
of a ferromagnetic matrix can lead to the opening of a complete
band gap, referred to as a magnonic band gap, in the spin-wave
spectrum. We use a model based on a homogeneous medium with
effective parameters to interpret the characteristics of the
obtained spin-wave spectra in the long wave limit. We also study
in detail the width of the band gap and its central frequency
versus the matrix material and the lattice constant. The
occurrence of a maximum width in the lattice-constant dependence
is shown to be closely related to the specific behaviour of the
dynamic magnetization profiles of the lowest excitations in the
spin-wave spectrum. On the basis of our results we determine the
conditions conducive to the occurrence of a complete magnonic band
gap. We also show that the crystallographic structure and the
lattice constant of the crystals produced by the protein
crystallization technique are almost optimized for the occurrence
of a magnonic band gap [2,3].
[1] O. Kasyutich et al., J. Appl. Phys. 105, 07B528 (2009).
[2] S. Mamica et al., Phys. Rev. B 86, 144402 (2012).
[3]
S. Mamica, J. Appl. Phys. 114, 043912 (2013).
/182/
Date: Wednesday 2013.12.04
Speaker: Dr Aleksandra Trzaskowska
Affiliation: Zakład Fizyki Kryształów, Wydział Fizyki UAM
Title: Periodic nanostructures on silicon surface
Abstract: During the seminar experimental and theoretical study of
the phononic band gap in the hypersonic range for thermally
activated surface acoustic waves will be presented. Two
dimensional phononic crystals have been studied by the Surface
Brillouin Light Scattering. The experiment was performed on the
(001) surface of the silicon loaded with two-dimensional square
and hexagonal lattice of pillars of different height (100 or 150
nm). It will be presented a new type of surface modes which are
related to phononic effects and mechanical eigenmodes of pillars.
The experimental data will be compared with results of theoretical
modeling by the Finite Element Method.
/181/
Date: Friday 2013.11.29
Speaker: Prof. Maciej Kozak
Affiliation: Macromolecular Physics Division, Physics Faculty, AMU
Title: SOLARIS - new light for Polish science
Abstract: In December 2011 was initiated in Kraków the
construction of the first Polish synchrotron - The National
Synchrotron Radiation Centre SOLARIS. The energy parameters of
SOLARIS (1.5 GeV) allow planning of beam lines utilising the
synchrotron radiation from infrared to hard X-rays range. Two
beamlines - UARPES (Ultra Angle Resolved Photoemission
Spectroscopy) and PEEM/XAS (Photoemission Electron
Microscopy/X-ray Absorption Spectroscopy) are currently under
construction. Four other new beamlines (IR spectroscopy, XAS/EXAFS
spectroscopy, Soft X-ray spectroscopies and multipurpose station -
macromolecular crystallography/small angle X-ray scattering/powder
diffractometry) are now at different stages of conception and
design. First research using synchrotron radiation in SOLARIS can
start at the beginning of 2015. The lecture summarized the
progress of the construction of the first Polish synchrotron and
research opportunities offered.
/180/
Date: Wednesday 2013.11.27
Speaker: Dr Tomasz Sowiński
Affiliation: Institute of Physics of the Polish Academy of
Sciences, Warsaw, Poland and Center for Theoretical Physics of the
Polish Academy of Sciences, Warsaw, Poland
Title: Spontaneous breaking of the time-reversal symmetry in
optical lattices
Abstract: The ground-state properties of bosons loaded into the
p-band of a one dimensional optical lattice is studied. It is
shown that the phase diagram of the system is substantially
affected by the anharmonicity of the lattice potential. In
particular, for a certain range of tunneling strength, the full
many-body ground state of the system becomes degenerate. In this
region, an additional symmetry of the system, namely the parity of
the occupation number of the chosen orbital, is spontaneously
broken. The state with nonvanishing staggered angular momentum,
which breaks the time-reversal symmetry, becomes the true ground
state of the system.
/179/
Date: Wednesday, 20 November 2013
Speaker: Dr hab. Konstantin Tretiakov
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, 60-179 Poznań
Title: The rate of energy dissipation determines probabilities of
nonequilibrium assemblies
Abstract: This work demonstrates that outside of thermodynamic
equilibrium, the rate at which energy is dissipated to maintain an
ordered state is related to the likelihood of this state being
observed. This result is based on a study of a model system in
which different (“polymorphic”) non-equilibrium structures are
realized for the same values of system’s parameters [1]. Because
the polymorphs differ only in the rates of energy dissipation,
ϵ – and not in their kinetic or potential energies – it
is possible to directly relate probabilities of polymorphs’
occurrence to ϵ. Combination of experiments and
simulations indicates that the probability of polymorph/”state”
occurrence decreases exponentially with its increasing dissipation
rate [2]. In other words, far from thermodynamic equilibrium,
nature favors less dissipative states, although the more
thermodynamically wasteful structures are also permitted with
small probabilities.
[1] B. A. Grzybowski, H. A. Stone, and G. M. Whitesides, Dynamic
self-assembly of magnetized, millimetre-sized objects rotating at
a liquid-air interface. Nature 405, 1033-1036 (2000).
[2] K. V. Tretiakov, I. Szleifer, and B. A. Grzybowski, The rate
of energy dissipation determines probabilities of non-equilibrium
assemblies, Angew. Chem. Int. Ed. 52, 10304-10308 (2013).
/178/
Date: Tuesday 2013.11.12
Speaker: Dr Marcin Pawłowski
Affiliation: Instytut Fizyki Teoretycznej i Astrofizyki,
Uniwersytet Gdański, 80-952 Gdańsk oraz Krajowe Centrum
Informatyki Kwantowej w Gdańsku, 81-824 Sopot
Title: Semi-device independent protocols
Abstract: After the second World War the British sold Enigma to
the governments of some of their former colonies claiming that it
was unbreakable. To counter untrusted vendors of the devices used
in communication tasks quantum information theory offers Device
Independent protocols, which can guarantee the security even if
the devices are rigged. However, these protocols require
parameters which are extremely difficult to obtain in real
experiments (so far no group has been able to demonstrate Device
Independent QKD). Semi-Device Independent protocols offer good
compromise between the level of trust in the vendor of the device
and the hardness of physical implementation. In this talk I will
introduce the Semi-Device Independent scenario, give the examples
of QKD and randomness expansion protocols and report on
experimental realizations.
/177/
Date: Friday 2013.11.08
Speaker: Prof. Anirban Pathak
Affiliation: Department of Physics, Jaypee Institute of
Information Technology (Deemed University), Noida, India.
Title: Can we build a reversible classical computer?
Abstract: Due to decoherence and other well-known issues, physical
realization of a scalable quantum computer is not expected to
happen in near future. However, it may be possible to design a
reversible classical computer that would be free from energy loss
due to logical operations. Due to other kind of existing losses it
may not be very attractive as a commercial product, but it is
interesting to investigate whether we are ready to build a
reversible classical computer. We show that we can really build
smart reversible circuits for almost all the essential component
of a computer. Thus in principle we can build a reversible
classical computer.
To elaborate on the above claim we first provide a short
introduction to the various quantitative measures of the quality
of reversible and quantum circuits. To provide a clear distinction
between classical reversible circuits and quantum circuits, some
foundational aspects of quantum mechanics (specially related to
measurement postulate, duality and monogamy) are discussed. The
physics behind the strategies adopted for the optimization of
various costs of quantum and reversible circuits are explained.
Subsequently, two algorithms for optimization of quantum cost are
described and optimized quantum costs of different reversible and
quantum circuits are shown. As examples, some useful optimized
quantum and reversible circuits designed by our group in recent
past are shown. Specifically, reversible designs of Montgomery
multiplier, sequential elements and ALU of a crypto-processor with
minimal gate count, garbage bits, optimal quantum cost and delay
are shown.
Further to show that optimization strategies discussed in context
of classical reversible circuits are also applicable to quantum
circuits, we provide a set of optimized quantum circuits useful
for construction of entanglement concentration protocols (ECPs)
for cat state, GHZ-like state and all families of 4-qubit
entangled states.
/176/
Date: Wednesday 2013.10.30
Speaker: Prof. Krzysztof Wojciechowski
Affiliation: Institute of Molecular Physics, Polish Academy of
Sciences, 60-179 Poznań
Title: Auxetic foams: how, when, why?
Abstract: Materials with anomalous (negative) Poisson's ratio are
called auxetics. In contrast to common materials, auxetics shrink
when stretched and expand transversally when axially compressed.
(Perfect auxetics preserve their shape when changing dimensions.
So, in some sense, they show a behaviour opposite to
incompressible liquids.) In spite that auxetic systems in the form
of man-made structures [1] or self-organising (thermodynamically
stable) phases [2] are known for more than 25 years, they are
still intensively studied for many potential applications [3,4].
In this lecture the research in the field of auxetics will be
briefly reviewed with emphasis on some recent results obtained for
auxetic foams [5].
[1] R. S.Lakes, "Negative Poisson's ratio materials", Science 235, 1038-1040 (1987).
[2] K. W. Wojciechowski, "Constant thermodynamic tension Monte Carlo studies of elastic properties of a two-dimensional systems of hard cyclic hexamers", Molecular Physics 61, 1247-125 (1987).
[3] Y. Prawoto, "Seeing auxetic materials from the mechanics point of view: A structural review on the negative Poisson's ratio", Computational Materials Science 58, 140-153 (2012).
[4] K. W. Wojciechowski, J. N. Grima, K. L. Alderson, J. Rybicki, "Preface - Auxetic Materials and Related Systems", Physica Status Solidi B 250, 1959-1962 (2013); see also the references therein.
[5] A. A. Pozniak, J. Smardzewski, and K. W. Wojciechowski,
"Computer simulations of auxetic foams in two dimensions", Smart
Materials and Structures 22, article 084009 (2013)
/175/
Date: Thursday 2013.10.17
Speaker: Dr Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Linear optical quantum routers
Abstract: This talk summarizes our recent results in the field of
quantum routing. First, we define a fully functional quantum
router with emphasis on the features such router has to provide.
Then we review some of the previously published schemes showing
the lack for genuine linear-optical quantum router for individual
photons. Subsequently we present our two proposals for
linear-optical quantum routers [1,2] and discuss their advantages
and disadvantages. Finally we address the experimental
implementation that is currently under construction in our
laboratory.
[1] K. Lemr, A. Černoch, Linear-optical programmable quantum
router, Opt. Comm. 300, 282-285 (2013).
[2] K. Lemr, K.
Bartkiewicz, A. Černoch, and J. Soubusta, Resource-efficient
linear-optical quantum router, Phys. Rev. A 87, 062333 (2013).
/174/
Date: Thursday 2013.10.17
Speaker: Dr Antonín Černoch
Affiliation: Institute of Physics of Academy of Science of the
Czech Republic, Joint Laboratory of Optics of PU and IP AS CR,
Olomouc, Czech Republic
Title: Linear-optical qubit amplifier
Abstract: We propose a linear-optical scheme for heralded qubit
amplification. The device is able to change the ratio between
probabilities of detecting vacuum or a photonic qubit in the
signal transmitted via some lossy channel by using a pair of
entangled ancillae. The probability of successful amplification
does not asymptotically drop to zero for infinite gain and it can
be optimized if (i) some a priory knowledge of input state is
known or (ii) some noise in the output signal is tolerated.
/173/
Date: Thursday 2013.10.17
Speaker: Doc. Jan Soubusta
Affiliation: Institute of Physics of Academy of Science of the
Czech Republic, Joint Laboratory of Optics of PU and IP AS CR,
Olomouc, Czech Republic
Title: Recent results of the experimental-optics group in Olomouc
Abstract: We summarize ten years of experiments dealing with
quantum cloning and implementations of linear-optical quantum
devices. We tried several concepts and several platforms for
optimal cloning of photon qubits. We developed several
linear-optical quantum information processing devices and we used
them for cloning.
/172/
Date: Thursday 2013.10.17
Speaker: Prof. Jan Peřina Jr.
Title: Sub-Poissonian-light generation by postselection from twin
beams
Authors: Jan Peřina, Jr.1, Ondrej Haderka2, Vaclav
Michalek2
1 RCPTM, Joint Laboratory of Optics of Palacký University and
Institute of Physics of AS CR, Palacký University, 17.
listopadu 12, 77146 Olomouc, Czech Republic
2 Institute of Physics of Academy of Sciences of the Czech
Republic, Joint Laboratory of Optics of Palacký University and
Institute of Physics of Academy of Sciences of the Czech Republic,
17. listopadu 12, 772 07 Olomouc, Czech Republic
Abstract: States with sub-Poissonian photon-number statistics
obtained by post-selection from twin beams are characterized.
States with Fano factors around 0.7 and mean photon numbers around
12 are experimentally reached. Their quasi-distributions of
integrated intensity attaining negative values are determined. An
intensified CCD camera with quantum detection efficiency exceeding
20 % is utilized both for post-selection and characterization.
Experimental results are compared with theory that provides
optimum conditions for the experiment.
/171/
Date: Thursday 2013.10.17
Speaker: Prof. Marek Czachor
Affiliation: Faculty of Applied Physics and Mathematics, Technical
University of Gdańsk and National Quantum Information Centre in
Sopot
Title: Are EPR correlations sensitive to the form of field
quantization?
Abstract: As is widely known, the standard "one oscillator per
one mode" quantization of free fields leads to the correct
physical prediction <AB>=cos(a-b) for entanglement of linear
polarizations, and violates the Bell inequality. This seems to
suggest that the tensor product structure associated with the
"oscillator per mode" quantization is indeed THE tensor
structure associated with quantum fields. However, I will show
that <AB>=cos(a-b) is typical also of fields quantized in a
different way, where there is no relation at all between the
number of modes and the number of oscillators.
/170/
Date: Thursday 2013.10.17
Speaker: Prof. Konrad Banaszek
Affiliation: Institute of Theoretical Physics, Department of
Quantum Optics and Atomic Physics, Faculty of Physics, University
of Warsaw
Title: Which-way experiment with an internal degree of freedom
Abstract: We present an inequality relating visibility and
which-way information for a particle equipped with an internal
degree of freedom travelling through a Mach-Zehnder
interferometer. The inequality paints an unexpectedly intricate
picture of wave-particle duality in the general case. Strikingly,
in some instances which-way information becomes erased by
introducing classical uncertainty in the internal degree of
freedom. Furthermore, even imperfect interference visibility
measured for a suitable set of inputs can be sufficient to infer
absence of which-way information.
/169/
Date: Thursday 2013.10.17
Speaker: Prof. Qiongyi He
Title: Einstein-Podolsky-Rosen paradox and quantum steering in
pulsed optomechanic
Authors: Q. Y. He1,2, M. D. Reid2, and P. D.
Drummond2
1 State Key Laboratory of Mesoscopic Physics, School of
Physics, Peking University, Beijing, China;
2 Centre for
Quantum Atom Optics, Swinburne University of Technology,
Melbourne, Australia
Abstract: We describe how to generate an Einstein-Podolsky-Rosen
(EPR) paradox between a mesoscopic mechanical oscillator and an
optical pulse. We find two types of paradox, defined by whether it
is the oscillator or the pulse that shows the effect Schrodinger
called “steering”. Only the oscillator paradox addresses the
question of mesoscopic local reality for a massive system. In that
case, EPR’s “elements of reality” are defined for the oscillator,
and it is these elements of reality that are falsified (if quantum
mechanics is complete). For this sort of paradox, we show that a
thermal barrier exists, meaning that a threshold level of
pulse-oscillator interaction is required for a given thermal
occupation n0 of the oscillator. We find there is no equivalent
thermal barrier for the entanglement of the pulse with the
oscillator, nor for the EPR paradox that addresses the local
reality of the optical system. Our work highlights the
asymmetrical effect of thermal noise on quantum nonlocality.
/168/
Date: Thursday 2013.10.17
Speaker: Prof. Zbigniew Ficek
Title: Role of the first-order coherence in entanglement between
Gaussian modes
Affiliation: The National Centre for Mathematics and Physics,
KACST, Riyadh, Saudi Arabia
In collaboration with: Li-hui Sun1 and Gao-xiang Li2
1 College of Physical Science and Technology, Yangtze
University, Jingzhou, P. R. China
2 Department of Physics, Huazhong Normal University, Wuhan, P.
R. China
Abstract: The coherence and entangled properties of coupled
Gaussian modes of optical systems are discussed. The systems
considered are (1) an atomic ensemble located inside a ring
cavity, and (2) an optical lattice trapped inside a cavity with a
movable mirror. We examine separately the cases of two-mode and
three-mode interactions, which are distinguished by a suitable
tuning of the mode frequencies. We find that the occurrence of
entanglement in the system is highly sensitive to the presence of
the first-order coherence between the modes. In particular, the
creation of the first-order coherence between modes is achieved at
the expense of entanglement between them.
/167/
Date: Thursday 2013.10.17
Speaker: Prof. Maciej Krawczyk
Affiliation: Nanomaterials Physics Division, Physics Faculty, AMU
Title: Review and prospects of magnonic crystals
Abstract: Magnonic crystals are the magnetic equivalent of
photonic crystals, with spin waves as the counterpart of
electromagnetic waves, playing the role of information carriers.
We will present short overview of research performed on magnonic
crystals offering tailored band structures for spin waves. The
promising directions of magnonic crystals research and its
applications will be briefly discussed.
/166/
Date: Thursday 2013.10.17
Speaker: Dr Przemysław Głowacki
Title: Spectroscopic investigations of the atomic structure in
support of quantum engineering and metrology
Authors: P. Głowacki1, A. Krzykowski1, A. Jarosz1, O. A.
Herrera-Sancho2, M. V. Okhapkin2, E. Peik2
1 Laboratory of Quantum Engineering and Metrology, Poznań University of Technology, Poland
2 Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
Abstract: The contribution is focused on spectroscopic investigations of electronic levels, in particular metastable ones, in free atoms and ions.
A system consisting of a metastable atomic state and the ground state is very favorable for optical atomic frequency standards, since the levels are connected via a forbidden transition with possible application as a "clock" transition. The same system of levels may serve as a basis for construction of a quantum bit.
Within the work some recent achievements in high precision spectroscopy of metastable levels in chromium atoms, obtained with ABMR-LIRF (laser - microwave double resonance on an atomic beam) method [1, 2], are presented. A brief review of experimental investigations of thorium ion structure aimed at construction of an extremely precise optical nuclear frequency standard [3], performed in cooperation in PTB, is also given.
[1] A. Jarosz, D. Stefańska, M. Elantkowska, J. Ruczkowski, A.
Buczek, B. Furmann, P. Głowacki, A. Krzykowski, Ł. Piątkowski, E.
Stachowska, J. Dembczyński, High precision investigations of the
hyperfine structure of metastable levels in chromium atom,
J. Phys. B: At. Mol. Opt. Phys. 40: 2785-2797 (2007).
[2] A. Krzykowski, P. Głowacki, A. Jarosz Precise measurements of
the hyperfine structure of the levels belonging to the terms
3d54s 5G and 5P in Cr(I),
Acta Phys. Pol. A, 122, 78-81 (2012).
[3] O. A. Herrera-Sancho, M. V. Okhapkin, K. Zimmermann, Chr.
Tamm, E. Peik, A. V. Taichenachev, V. I. Yudin, P. Głowacki,
Two-photon laser excitation of trapped 232Th+ ions via the
402-nm resonance line Phys. Rev. A 85, 033402 (2012).
/165/
Date: Thursday 2013.10.17
Speaker: Dr hab. Ireneusz Weymann
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: The Kondo effect in quantum dots
Abstract: Quantum dots are promising candidates for future quantum
computing devices. They are also considered as ideal model systems
to study fundamental correlations and interactions between single
charges and spins. We will here present the basic transport
properties of quantum dots coupled to external leads, with a
special focus on the strong coupling regime where the electronic
correlations can give rise to the Kondo effect. The case of the
spin S=1/2 Kondo effect will be analyzed for quantum dots with
both nonmagnetic and ferromagnetic leads. Moreover, we will also
discuss the SU(4) Kondo effect, which can occur in double quantum
dots when the system possesses both spin and orbital degeneracy.
/164/
Date: Thursday 2013.10.17
Speaker: Prof. Alexandre Zagoskin
Affiliation: Loughborough University, UK
Title: Quantum metamaterials: concept and applications
Abstract: Quantum metamaterials are optical media comprised of
artificial quantum scatterers (e.g., qubits), in such a way that
(1) these unit blocks maintain quantum coherence for times
exceeding the characteristic travel time of an electromagnetic
wave through the system, and (2) their quantum state can be
directly controlled. For example, a periodic arrangement of qubits
in a register of an adiabatic quantum computer can be considered
as a quantum metamaterial.
The simplest case of a quantum metamaterial is a one-dimensional
set of superconducting qubits in a transmission line. It was shown
in experiment that a single qubit in such a line demonstrates all
the expected of a pointlike quantum scatterer, with a much
stronger coupling to the field than can be achieved with natural
atoms in 3D space. Other implementations of quantum metamaterials
(like quantum dots placed inside photonic crystals, which would
operate in the optical range) are also being considered.
In my talk I will discuss some of the unusual properties of a
quantum metamaterial, which stem from its being an extended
quantum object, and their possible applications.
/163/
Date: Wednesday 2013.10.16
Speaker: Prof. Jan Martinek
Title: Cooper pair splitting as a source of entangled electrons
Authors: Jan Martinek1, D. Tomaszewski1, M. Czechlewski1,
P. Rożek1, R. Zitko2, R. Lopez3, M. Lee4, W.
Kłobus5, A. Grudka5, A. Baumgartner6, and C.
Schonenberger6
1Institute of Molecular Physics, Polish Academy of Sciences, 60-179 Poznań, Poland
2Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
3Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
4Department of Physics, Kyung Hee University, Yongin 446-701, Korea
5Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
6Department of Physics, University of Basel, CH-4056 Basel,
Switzerland
Abstract: We study an entangled state of spatially separated
electrons, in particular its spins, in a solid state electronic
system. The ground state of conventional superconductors is a
singlet state of electron Cooper pairs that can provide a natural
source of entangled electrons. One of the proposals to obtain the
nonlocal entanglement of electrons is to use the Cooper pairs
split in the Double Quantum Dot (DQD) system using the Coulomb
interaction between electrons [1]. We have analyzed an efficiency
of the separation of Cooper pairs in systems, where the DQD is
connected to the two superconducting leads, or to the
superconducting and normal leads [2,3]. Addressing the idea of
quantum communication with entangled electrons in a solid state,
where ferromagnetic detectors allow for spin correlation
detection, we provide, using quantum information theory, a lower
bond on the spin polarization of detectors [4]. In ferromagnetic
detectors the spin information is transformed into charge
information, however, any real magnetic materials feature
imperfect spin polarization due to presence of both spin component
in density of states at the Fermi surface. We find that lower bond
for the spin polarization is p > 58% for detection of
entanglement using an optimal entanglement witness [4]. It
provides the minimal spin polarization of ferromagnetic materials
that can be useful in quantum communication.
[1] L. Hofstetter, S. Csonka, J. Nygard, and C. Schönenberger, Nature 461, 960 (2009).
[2] J. Eldridge, M. G. Pala, M. Governale, and J. König, Phys. Rev. B 82, 184507 (2010).
[3] R. Zitko, J. Lim, R. Lopez, J. Martinek, P. Simon, Phys. Rev. Lett. 108, 166605 (2012).
[4] W. Kłobus, A. Grudka, A. Baumgartner, D. Tomaszewski, C.
Schönenberger, and J. Martinek, (in preparation).
/162/
Date: Wednesday 2013.10.16
Speaker: Dr Tomasz Polak
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Gauge dependent time of flight patterns in Abelian
synthetic magnetic fields
Abstract: I will show how to calculate the time-of-flight patterns
of strongly interacting bosons confined in two-dimensional square
lattice in the presence of an artificial magnetic field. I will
discuss the cases with the artificial magnetic field being
uniform, staggered or forming a checkerboard configuration.
Effects of additional temporal modulation of the optical potential
that results from application of Raman lasers driving particle
transitions between lattice sites are also included. The presented
time-of-flight patterns may serve as a verification of chosen
gauge in experiments, but also provide important hints on
unconventional, non-zero momentum condensates, or possibility of
observing graphene-like physics resulting from occurrence of Dirac
cones in artificial magnetic fields in systems of ultra-cold
bosons in optical lattices. Also, I elucidate on differences
between effects of magnetic field in solids and the artificial
magnetic field in optical lattices, which can be controlled on
much higher level leading to effects not possible in condensed
matter physics.
/161/
Date: Wednesday 2013.10.16
Speaker: Dr Tomasz Sowiński
Affiliation: Institute of Physics of the Polish Academy of
Sciences, Warsaw, Poland and Center for Theoretical Physics of the
Polish Academy of Sciences, Warsaw, Poland
Title: Universality of extended Bose-Hubbard models with local
three-body interactions
Abstract: Experimental progress on trapping and manipulating
ultra-cold atoms confined in optical lattices has opened new
perspectives for controlling many-body states of different quantum
systems. In the simplest case such systems are described in the
context of the Bose-Hubbard (BH) model. In my talk I will consider
the class of extended BH models with additional three-body on-site
interactions. After short introduction I will divide the talk into
two parts: (i) Standard BH with additional three-body term: I will
show that the shape of insulating lobes may crucially depend on
the three-body interactions and in the case of attractive
three-body term may lead to vanishing of the second insulating
lobe [1,2]. (ii) Attractive BH model with soft-core three-body
repulsion: I will show that the critical behavior of the system
undergoing a phase transition from pair-superfluid to superfluid
at integer filling depends on the value of the three-body
repulsion. In particular, a critical exponent and the central
charge governing the quantum phase transitions are shown to have
repulsion dependent features. In consequence, the model extends
the list of known systems violating the universality hypothesis
[3].
[1] T. Sowinski, Phys. Rev. A 85, 065601 (2012).
[2] T. Sowinski, ArXiv:1307.6852 (2013).
[3] T. Sowinski, R. W. Chhajlany, O. Dutta, L. Tagliacozzo, M.
Lewenstein, ArXiv:1304.4835 (2013).
/160/
Date: Wednesday 2013.10.16
Speaker: Prof. Jan Mostowski
Affiliation: Institute of Physics, Polish Academy of Sciences,
Warsaw, Poland
Title: Time crystals
Abstract: A system of two charged particles in a harmonic trap
with additional magnetic field is considered. The problem is
reduced to a single-particle one in relative coordinates. The
ground- and lowest excited-state energies and wave functions are
found. The ground state exhibits non-zero expectation value of the
velocity (kinetic momentum) and the probability current density
does not vanish as well. When the ground state becomes degenerate
the expectation value of velocity becomes discontinuous. The
effects associated with turning on of the magnetic field are
studied by solving the appropriate time-dependent Schroedinger
equation. No substantial differences between abrupt (discontinuous
in time) and continuous switching on have been observed. Evolution
of a wave packet which is initially Gaussian is also investigated.
The wave packet loses its Gaussian nature and, after sufficiently
large time, a system of diffractive maxima and minima is built.
/159/
Date: Wednesday 2013.10.16
Speaker: Prof. Karol Życzkowski
Affiliation: Jagiellonian University, Kraków & Center for
Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland
Title: Measuring the degree of quantum entanglement
Abstract: Measures of quantum entanglement are reviewed and
compared. We focus quantities characterizing entanglement which
could be experimentally accessible. A quantity called
'collectibility' is proposed which can be determined in a
coincidence experiment involving two copies of the state analyzed.
Our approach, initially designed for the case of pure states,
works also in the general case of mixed quantum states of a
multi-partite system.
/158/
Date: Wednesday 2013.10.16
Speaker: Prof. Paweł Horodecki
Affiliation: Faculty of Applied Physics and Mathematics, Technical
University of Gdańsk and National Quantum Information Centre in
Sopot, Poland
Title: Device independent arbitrary weak randomness amplification
with noise tolerance
Abstract: Recently the protocols of randomness amplification have
been introduced secure against quantum and no-signaling
adversaries. Here we present the first fully constructive proof of
existence of the protocol that is secure against general
no-signaling adversary and amplifies arbitrary small randomness
(in standard terms of Santha-Vazirani source) in a fully device
independent way. The protocol tolerates some amount of noise
depending among others on the initial randomness that is to be
amplified.
/157/
Date: Wednesday 2013.10.16
Speaker: Prof. Marek Kuś
Affiliation: Center for Theoretical Physics, Polish Academy of
Sciences, Warsaw, Poland
Title: Engineering SU(3) models: trapped ions, quantum chaos,
classical limit(s)
Abstract: One of the current trends in quantum physics is the
quest for controllable quantum many-body systems which can be used
as quantum simulators. In particular, there is a growing interest
in simulating spin and quantum magnetism. In recent years, the
focus is moving from SU(2) spins towards SU(N)-symmetric models.
The SU(3) systems, having their origin in nuclear physics, were a
fruitful playground for quantum chaos investigations, in
particular due to they reach possible behavior in the classical
limit. Now it seems to be possible to realize such models
experimentally with trapped ions providing a large degree of
control from the experimental point of view.
/156/
Date: Wednesday 2013.10.16
Speaker: Prof. Werner Vogel
Title: Unified representation of nonclassicality and entanglement
Authors: Werner Vogel and Jan Sperling
Arbeitsgruppe Quantenoptik, Institut für Physik, Universität
Rostock, D-18051 Rostock, Germany
Abstract: In Quantum Optics the widely used definition of
nonclassicality is based on the Glauber-Sudarshan P function
[1]. If the P function has the properties of a classical
probability density, the state is a classical mixture of coherent
states. In any other case, the quantum state clearly shows quantum
interference effects. In general, the P function is strongly
singular and, hence, not applicable in experiments. A universal
regularization resolves this problem [2], as it was demonstrated
in experiments. In view of its structure [3], entanglement can
also be visualized by quasiprobabilities. This requires an
optimization based on the solution of the separability eigenvalue
problem [4]. Its extension to the multipartite case yields
multipartite entanglement witness for complex quantum states [5].
To characterize general quantum correlations, the concept of the
P function was extended to a functional [6]. Its regularized
version visualizes quantum correlations, even when the state is
not entangled and has zero quantum discord [7].
[1] E. C. G. Sudarshan, Phys. Rev. Lett. 10, 277 (1963); R. J. Glauber, Phys. Rev. 131, 2766 (1963).
[2] T. Kiesel and W. Vogel, Phys. Rev A 82, 032107 (2010).
[3] R. F. Werner, Phys. Rev. A 40, 4277 (1989).
[4] J. Sperling and W. Vogel, Phys. Rev. A 79, 042337 (2009).
[5] J. Sperling and W. Vogel, Phys. Rev. Lett. 111, 110503 (2013).
[6] W. Vogel, Phys. Rev. Lett. 100, 013605 (2008).
[7] E. Agudelo, J. Sperling, and W. Vogel, Phys. Rev. A 87, 033811
(2013).
/155/
Date: Wednesday 2013.10.16
Speaker: Prof. Andrzej Grudka
Title: Universal scheme for violation of local realism from
quantum advantage in one-way communication complexity
Authors: L. Czekaj1, A. Grudka2, M. Horodecki1, P.
Horodecki3, and M. Markiewicz1
1Faculty of Mathematics, Physics and Informatics, Gdańsk University, 80-952 Gdańsk,Poland
2Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
3Faculty of Applied Physics and Mathematics, Gdańsk University
of Technology, 80-952 Gdańsk, Poland
Abstract: We consider relations between communication complexity
problems and detecting correlations (violating local realism) with
no local hidden variable model. We show first universal
equivalence between characteristics of protocols used in that type
of problems and non-signaling correlations. We construct non
linear bipartite Bell type inequalities and strong nonlocality
test with binary observables by providing general method of Bell
inequalities construction and showing that existence of gap
between quantum and classical complexity leads to violation of
these inequalities. We obtain, first to our knowledge, explicit
Bell inequality with binary observables and exponential
violation.
/143/
Date: Wednesday 2013.10.16
Speaker: Prof. Dariusz Chruściński
Affiliation: Institute of Physics, Faculty of Physics, Astronomy
and Informatics, Nicolaus Copernicus University, Grudziądzka 5,
87-100 Toruń, Poland
Title: Non-Markovian quantum dynamics
Abstract: We discuss recent concepts of non-Markovianity of
quantum evolution. The discussion is illustrated by simple
examples (pure decoherence, amplitude damping and random unitary
dynamics).
/153/
Date: Wednesday 2013.10.16
Speaker: Prof. Marek Żukowski
Title: Generalized Hardy correlations and quantum communication
problems
Authors: Ramij Rahaman, Marcin Wieśniak, and Marek Żukowski
Abstract: We present multi-partite Hardy-type test against local
realism. For n qubit systems, we prove the uniqueness and purity
of the Hardy state (that is the one that satisfies Hardy
conditions), and its genuine n-partite entanglement. We show an
that Hardy correlations allow one to find solutions to some
quantum communication problems. As an example we present a secure
quantum scheme for the original Byzantine Generals problem.
Our protocol is based on Hardy's paradox, which uses a set of
conditions impossible for classical systems, but satisfied by a
unique quantum two-particle state, and on entanglement swapping
methods.
/152/
Date: Wednesday 2013.10.16
Speaker: Prof. Ryszard Horodecki
Affiliation: Instytut Fizyki Teoretycznej i Astrofizyki,
Uniwersytet Gdański, 80-952 Gdańsk oraz Krajowe Centrum
Informatyki Kwantowej w Gdańsku, 81-824 Sopot, Poland
Title: Objectivity from first principles - new role of
broadcasting structure
Abstract: Incessant run of successes of quantum mechanics suggests
that quantum formalism plays decisive role in the description of
physical phenomena. It leads inevitably to the problem: How does
Nature create a "foot-bridge" from fragile quanta to the
objective world of everyday experience? The subject of the talk
will provide an answer to this fundamental issue. We will show how
a crucial for quantum mechanics notion of non-disturbance due to
Bohr and a natural definition of objectivity lead to a canonical
spectrum broadcasting structure of a quantum system-environment
state, reflecting objective information records about the system
stored in the environment.
/151/
Date: Tuesday 2013.10.15
Speaker: Prof. Tadeusz Lulek
Affiliation: Mathematical Physics Division, Physics Faculty, AMU
Title: Nonlinear magnetooptics, symmetry breakings and ascents,
and the magnetic translation groups
Abstract: This commemoration intertwines between various physical
ideas (as presented in the title), shared within the scientific
works of Professors: Stanisław Kielich, Louis Michel, Jan
Mozrzymas, Joshua Zak, Marian Surma, and others. It goes from
experimental studies on Cotton-Mouton effect (heavy
electromagnesses in the basements of Collegium Chemicum), through
symmetry considerations in phase transitions (nematics, smectics,
etc., mainly breaking of symmetry, but, somehow exceptionally,
also ascent), to the magnetic translation group as a mathematical
tool for the Bohm-Aharonov effect (everybody knows Landau levels
of a free two-dim electron gas, and the magnetic translation group
serves as an equivalent for the case of itinerant electrons, with
its irreducible representations labeling the levels, and the basis
functions describing degenerate cyclotronic orbits). Nowadays,
these ideas can be converted to "reality" within nanotechnology,
e. g. magnetic quantum dots.
/150/
Date: Tuesday 2013.10.15
Speaker: Prof. Anna Zawadzka
Affiliation: Institute of Physics, Faculty of Physics, Astronomy
and Informatics, Nicolaus Copernicus University, Grudziądzka 5,
87-100 Toruń, Poland
Title: Nonlinear optical properties of organometallic thin films
Abstract: This work contains investigation results of the
structural and nonlinear optical properties of organometallic thin
films and nanostructures. The films and nanostructures were
successfully grown by Physical Vapor Deposition technique in high
vacuum on transparent (quartz, glass) and semiconductor (n-type
silica) substrates kept at room temperature during the deposition
process. Selected films were annealed after fabrication in ambient
atmosphere for 24 hours at the temperature in the range from
50oC to 250oC. Spectral properties were examined using
transmission, photoluminescence, Second and Third Harmonic
Generation's techniques. The experimental spectra were allowed to
determine optical constant of the films. Structural properties
were investigated by AFM measurements. The organometallic films
and nanostructures exhibit high structural quality regardless of
the annealing process, but the stability of the film can be
improved by using an appropriate temperature during the annealing
process. We find that the optical properties were strictly
connected with the morphology and the annealing process can
significantly change the structural properties of the films and
lead to the formation of various nanostructures.
/149/
Date: Tuesday 2013.10.15
Speaker: Prof. Małgorzata Makowska-Janusik
Affiliation: Institute of Physics, Jan Długosz University,
Częstochowa, Poland
Title: Macroscopic optical properties of composite materials -
computational approach
Abstract: One of the possibilities to obtain efficient and stable
nonlinear optical (NLO) material is to dope an amorphous polymer
with organic donor-acceptor molecules forming a composite. The
appropriate material for the first NLO effect as persistent second
harmonic generation (SHG) requires large number of polarizable
molecules embedded in polymeric matrix preventing polar
orientation. The polar orientation may be induced by external
electric field at the temperatures where the matrix is
sufficiently mobile to allow fast alignment of the dopants. The
experimental explanation of the origin of their NLO response is
very difficult because optical susceptibilities are measured in
condensed matter where the molecular properties are affected by
the host matrix. Molecular simulations can help to explain the
nature of the guest-host interaction and separate the different
contribution of the material to the optical output signal. A goal
of many theoretical works is to find appropriate model describing
optical properties of molecules incorporated into polymeric
environment.
In the presented work linear and nonlinear optical
susceptibilities of guest-host polymer systems were calculated
applying the hierarchic procedure . The wild variety of
chromophores characterized by different size, shape and charge
distribution incorporated into different polymer matrix were
studied. First of all the structures of the investigated systems
have been modeled by molecular dynamic simulations applying
molecular mechanics CVFF force field method. The obtained
structures are amorphous. Investigations of radial distribution
function prove that location of chromophores in polymeric matrix
is an intrinsic property of polymer. The motion of polymer chain
allows a rotation of dopants under influence of an external
electric field.
The electronic properties of the NLO chromophores were computed at
the HF and DFT level using different exchange - correlation
potentials. These properties were investigated for the isolated
NLO molecules as well as for the ones in polymer environment. In
the second case the first-order susceptibilities corresponding to
SHG were calculated using discrete local field approach. The
implemented method is very efficient to the molecules with high
charge transfer effect and give the data approximately consistent
with the experimental results. It was also proved that the optical
response, especially NLO output signal of chromophores embedded
into polymeric matrix, depends on their local environment.
/148/
Date: Tuesday 2013.10.15
Speaker: Prof. Jean-Luc Godet
Affiliation: University of Angers, UFR Sciences Institute of
Sciences and Molecular Technologies of Angers, France
Title: A short historical recall about the story of the concept of
refractive index: From the Antique to the 19th century.
Abstract: The research of a refraction law played a major role in
the development of the optics since the first attempts of Ptolemy
until the more accomplished results of Ibn Sahl, Snel or
Descartes. However, it is necessary to wait for the beginning of
the XIXth century, much later than the theory of colours of Newton
and thanks to the researches on the achromatic glasses, so that
emerges the concept of refractive index and so that it begins to
be understood well. We propose a historical reminder and an
outline of the obstacles and epistemological advances which
allowed to establish it.
/147/
Date: Tuesday 2013.10.15
Speaker: Prof. Jerzy Warczewski
Title: Spin glass state and other magnetic structures with their
symmetries in terms of the Fibre Bundle Approach
Authors: Jerzy Warczewski1, Paweł Gusin2 and Daniel
Wojcieszyk1
1University of Silesia, Institute of Physics, 40-007 Katowice,
Poland
2University of Wrocław, Institute of Theoretical Physics,
50-204 Wrocław, Poland
Abstract: The fibre bundle approach [1] has been applied to the
unified description of all the eight fundamental magnetic
structures and their symmetry groups [2]. On this basis the
explicit formulas describing both the variety of magnetic
structures and their symmetry groups have been derived. In the
particular case of the spin glass state (SGS) the global magnetic
coupling constant has been interpreted as a section of the
corresponding fibre bundle. The fibre of this bundle makes the
space of the Gaussian distributions. Thus one can say that the
randomness of the distribution of both the magnetization and the
individual magnetic moments in the SGS is of the Gaussian-like
character. An observation was made that another kind of the fibre
bundle sections make the magnetization vectors M multiplied
by a certain Gaussian factor defined in R3, the last factor
making the problem continuous and more physical [3, 4]. In one of
the previous papers the authors have proved that an internal
spontaneous magnetic field Hint is necessary for the SGS to
be stable and just to exist [5]. For the angle between M and
Hint equal to ϕ one can say that at ϕ=const any
rotation (precession) of M around the direction of Hint
makes the operation of symmetry of the SGS. Thus the magnetic
symmetry group of SGS turns out to be SO(2). The role of both the
Hint and the external magnetic field Hext as well as of
the average kinetic energy Ekin of the separate magnetic
atoms in the explanation of the experimental temperature
dependencies of susceptibility is shown. Thus the fibre bundle
approach equates the method of the symmetry analysis of magnetic
structures with the method of the higher dimensional embeddings of
the modulated structures. The symmetry groups appearing in the
method of the symmetry analysis become the structural groups of
the bundles. From the other side a higher dimensional space needed
to the description of a modulated structure makes here the total
space of the bundle. Thus these three methods, namely the
symmetry analysis, the higher dimensional embeddings and
the fibre bundles are equivalent. The analogous situation
is with the description of the magnetic structures with the use of
the spin groups, where an additional type of symmetry is
introduced. Note that the Gaussian factor introduced above plays a
double role: it makes the vector M to be a field and
simultaneously makes the description of the magnetic structures
more physical [6, 7]. It seems that the fibre bundle approach
could serve also for the description of the symmetry groups of all
the other aperiodic structures, like e.g. the modulated
nonmagnetic structures, quasicrystals (nonmagnetic and magnetic)
etc. It is worthwhile to mention here that these different
magnetic structures under consideration have been found by the
authors to be related with the values of the certain topological
invariants [8].
[1] Sulanke, R. Wintgen, P., Differentialgeometrie und
Faserbundel, Berlin (1972)
[2] J. Warczewski, P. Gusin, D. Wojcieszyk, Mol. Cryst. Liq.
Cryst. 554 (2012), 209-220
[3] J. Warczewski, P. Gusin et al. Central European Journal of
Physics 5(3) 2007 377-384
[4] P. Gusin and J. Warczewski, Mol. Cryst. Liq. Cryst. Vol. 521:
pp. 288-292, 2010
[5] J. Warczewski, P. Gusin et al., J. Phys.: Condens. Matter, 21
(2009) pp. 035402- 035407
[6] J. Warczewski, J. Krok-Kowalski, P. Gusin et al., J. of
Non-Linear Optics, Quantum Optics, Vol. 30, (2003) pp. 301-320
[7] J. Warczewski, J. Krok-Kowalski, P. Gusin et al., Journal of
Physics and Chemistry of Solids 66 (2005) 2044-2048
[8] P. Gusin and J. Warczewski, J. of Magn. and Magn. Mat., 2004,
28(1/2-3), 178-187
/146/
Date: Tuesday 2013.10.15
Speaker: Prof. Igor Lyubchanskii
Title: Nonlinear magneto-optical ellipsometry
Authors: Yu. S. Dadoenkova1, I. L. Lyubchanskii1,2, Y.P.
Lee3, and Th. Rasing4
1Donetsk Physical and Technical Institute of the National Academy of Sciences of Ukraine, 83114, Donetsk, Ukraine
2Department of Physics and Technology, Donetsk National University, 83001, Donetsk, Ukraine
3Quantum Photonic Science Research Center (q-Psi) and Hanyang University, 133-791, Seoul, Republic of Korea
4Radboud University Nijmegen, Institute for Molecules and
Materials, 6525 AJ, Nijmegen, the Netherlands
Abstract: The ellipsometric parameters for light reflection from a
dielectric film with Kerr optical nonlinearity on a bigyrotropic
magneto-electric film are theoretically investigated. The combined
contributions of the cubic optical nonlinearity and the
magneto-electric coupling allows to control the ellipsometric
parameters and thus for example the Kerr rotation with the
incoming light intensity, in particular at incidence angles close
to the pseudo-Brewster angle.
/145/
Date: Tuesday 2013.10.15
Speaker: Prof. Georges Boudebs
Affiliation: Laboratoire de photonique d'Angers (LPhiA),
University d'Angers, France
Title: Optical nonlinear characterization using imaging technique
in a 4f-Z-scan system
Abstract: We show that the direct measurement of the beam radius
in Z-scan experiments using a CCD camera at the output of a
4f-imaging system allows a higher sensitivity and a better
accuracy than other methods. One of the advantages is to be
insensitive to pointing instability of the pulsed laser because no
hard aperture is employed as in the usual Z-scan. In addition, the
numerical calculations involved here and the measurement of the
beam radius are simplified since we do not measure the
transmittance through an aperture and it is not subject to
mathematical artefacts related to a normalization process,
especially when the diffracted light is very low.
Keywords: Nonlinear optics, Z-scan, diffraction, image
processing, Fourier optics
/144/
Date: Tuesday 2013.10.15
Speaker: Prof. Dobrosława Kasprowicz
Title: Opportunities for Bi2ZnOB2O6 single crystals:
Second and third order nonlinear optical applications
Authors: D. Kasprowicz1, K. Iliopoulos2, A. Majchrowski3,
and B. Sahraoui2
1Faculty of Technical Physics, Poznań University of Technology,
Nieszawska 13 A, 60-965 Poznań,
Poland
2LUNAM Université, Université d'Angers, CNRS UMR 6200,
Laboratoire MOLTECH-Anjou, 2 Bd Lavoisier, 49045 Angers
Cedex, France
3Institute of Applied Physics, Military University of
Technology, Kaliskiego 2, 00 - 908 Warszawa, Poland
Abstract: Bi2ZnOB2O6 nonlinear optical single crystals
were grown by means of the Kyropoulos method from stoichiometric
melt. The SHG and THG response of the Bi2ZnOB2O6 crystal
was studied by the Maker fringes techniques. Moreover SHG
microscopy studies were carried out providing two-dimensional SHG
images as a function of the incident laser polarization. The
crystals have been shown to have high SHG and THG efficiency,
comparable with those of well-known crystals such as BBO, KDP,
KTP, which makes them very attractive materials for NLO
applications. The high nonlinear optical efficiency combined with
the possibility to grow high quality crystals make
Bi2ZnOB2O6 an excellent candidate for photonic
applications.
/143/
Date: Tuesday 2013.10.15
Speaker: Prof. George Maroulis
Affiliation: Department of Chemistry, University of Patras, Greece
Title: Quantifying the performance of quantum chemistry methods
Abstract: We present a general method for the quantification of
the performance of quantum chemical methods over an arbitrary
collection of atomic/molecular properties. Our approach relies on
the Minkowski metric, graph theoretic concepts and pattern
recognition techniques. The method should be of interest as a
rigorous approach to the introduction of order and classification
in spaces of theoretical descriptions. We show how it can be used
to quantify the relative merit of ab initio and DFT methods.
/142/
Date: Tuesday 2013.10.15
Speaker: Prof. Keith Gubbins
Affiliation: Department of Chemical & Biomolecular Engineering,
North Carolina State University, Raleigh, NC 27695-7905, U.S.A.
Title: The Theory of Polar Liquids and Their Mixtures: A
Historical Review
Abstract: The primary goal of a theory of liquid mixtures is to
determine, using statistical mechanics, how the structure and free
energy varies with the composition, and with the chemical
composition of its components. Such a theory provides the key to
the determination of dielectric and spectral properties, phase
transitions, critical points, solubilities, immiscible regions,
metastable and unstable regions, etc.
Theories proposed in the first half of the 20th century were, for
the most part, lattice theories, and many of these are described
in the books by Guggenheim [1] and Prigogine [2]. These early
theories pre-dated molecular simulations and the availability of
electronic computers, so that they were “tested” by direct
comparison with experimental data. Since such comparisons, in the
case of the lattice theories, involved adjustment of various
parameters to experimental data, these tests were of dubious
value. Once molecular simulation data became available in the
early 1960’s these theories were shown to be in serious error, and
can now be considered to be extinct.
Modern theory of polar liquids (the last 60 years) has followed a
dual path. The first has been perturbation theory, in which the
free energy and other properties of the solution of interest are
related to those of a simpler solution having simple
intermolecular forces, for example hard spheres or Lennard-Jones
mixtures. Perturbation theory has been particularly successful for
thermodynamic properties. The theory of Wertheim [3], relates the
free energy of a polar or associating fluid to that of a hard body
(non-associating) fluid through a clever resummation of a cluster
series for the free energy. It and its later extensions are
finding widespread practical application [4].
The second route to a theory of polar liquids has been integral
equation theory, which yields the structure in the form of
distribution functions [5]. Although less successful than the
perturbation theories for thermodynamic properties, integral
equation theories have been successful for other properties, in
particular dielectric and spectral properties.
References
[1] E.A. Guggenheim, “Mixtures”, Clarendon Press, Oxford, 1952.
[2] I. Prigogine, “The Molecular Theory of Solutions”,
North-Holland Pub. Co., Amsterdam, 1957.
[3] Wertheim, M.S. J. stat. Phys. 35, 19 (1984); ibid. 35, 35
(1984); ibid. 42, 459 (1986); ibid. 42, 477 (1986).
[4] For reviews of the theory and its extensions, and practical
applications, see: Müller, E.A. and Gubbins, K.E. Ind. Engng.
Chem. Research, 40, 2193 (2001); Tan, S.P., Adidharma, H. and
Radosz, M., Ind. Eng. Chem. Research, 47, 8063 (2008).
[5] C.G. Gray and K.E. Gubbins, Theory of Molecular Fluids. I.
Fundamentals, Chap. 5, Oxford University Press (1984); C.G. Gray,
K.E. Gubbins and C.G. Joslin, Theory of Molecular Fluids. II.
Applications, Chap. 9-11, Oxford University Press (2011).
/141/
Date: Tuesday 2013.10.15
Speaker: Prof. Tadeusz Hilczer
Affiliation: Division of Dielectrics Physics, Physics Faculty, AMU
Title: The early days of physics of dielectrics in Poznań
Abstract: Physics of dielectrics started in Poznań when professor
Arkadiusz Piekara took chair in Experimental Physics at the Poznań
University in 1952. At the beginning a lot of effort was taken to
prepare the measuring basis, that is to construct the measuring
condensers, Schering bridges, resonance circuits, heterodyne beat
apparatus (∆C/C ≈ 10−6), to purifying liquid
dielectrics and to synthesize ferroelectrics. Later, professor
Piekara got Stanisław Kielich interested in theoretical approach
to the physics of dielectrics and his Master of Science
dissertation in 1955 can be considered as the beginning of the
work of young Poznań staff in theory of dielectrics.
/140/
Date: Tuesday 2013.10.15
Speaker: Ms. Natalia Kielich-Buchowska, Prof. Tadeusz
Bancewicz1, and Prof. Ryszard Tanaś1
Affiliation: 1Nonlinear Optics Division, Physics Faculty, AMU
Title: Stanisław Kielich - a few words about his life
/139/
Date: Wednesday 2013.06.19
Speaker: Dr Semanti Pal
Affiliation: Thematic Unit of Excellence on Nanodevice Technology
and Department of Condensed Matter Physics and Material Sciences,
S. N. Bose National Centre for Basic sciences, Block JD, Sec III,
Salt Lake, Kolkata 700098, India
Coauthors: Saswati Barman, Olav Hellwig, and Anjan Barman
Title: Effect of the Spin-Twist Structure on the Spin-Wave
Dynamics of the Fe55Pt45/Ni80Fe20 Exchange Coupled Bi-layers with
varying Ni80Fe20 Thickness
Abstract: We have investigated optically induced ultrafast
magnetization dynamics of a series of Fe55Pt45/Ni80Fe20 exchange
spring bi-layers with varying Ni80Fe20 thickness by time-resolved
magneto-optical Kerr effect measurements. Rich spin wave spectra
are observed and the spin-wave frequency shows a strong dependence
on the Ni80Fe20 layer thickness. Micromagnetic simulations
reproduced the experimental data qualitatively after considering
pinning of spins at the Fe55Pt45/ Ni80Fe20 interface and an
effective magnetic field gradient across the thickness of the
Ni80Fe20 layer. The spin twist structure introduced in the
Ni80Fe20 layer gives rise to new modes in the composite system as
opposed to the bare Ni80Fe20 films.
/138/
Date: Wednesday 2013.06.05
Speaker: Prof. Andrzej Grudka
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Randomness amplification based on no-signaling principle
(Wzmacnianie losowości w oparciu o zasadę niesygnalizowania)
Abstract: We analyze the protocol of randomness amplification
using Bell inequality violation in terms of the convex combination
of no-signaling boxes required to simulate quantum violation of
the inequality. We present intuitive proof for the range of
partial randomness from which perfect randomness can be extracted
using quantum correlations violating the chain inequalities. We
derive exact values in the asymptotic limit of a large number of
measurement settings.
/137/
Date: Wednesday 2013.05.29
Speaker: Dr hab. Ireneusz Weymann
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Dynamics in single impurity Anderson model: Testing the
eigenstate thermalization hypothesis
Abstract: We analyze the eigenstate thermalization hypothesis
(ETH) for the single impurity Anderson model, focusing on the
Kondo regime. For this we construct the complete eigenbasis
of the Hamiltonian using the numerical renormalization group
method in the language of the matrix product states. We
calculate the spectral function of the quantum impurity (a
quantum dot) for the ground state and several excited states
of the system using the microcanonical and diagonal
ensembles. These spectral functions are compared to the
time-averaged spectral function obtained by time-evolving the
initial state according to the full Hamiltonian and to the
spectral function calculated using the thermal density
matrix. We find good agreement between the spectral functions
calculated this way, which indicates that the process of
thermalization happens at the level of individual
eigenstates, indeed. We also discuss the behavior of the
spectral functions calculated for states with the bath
initially in its ground state. In certain cases then, this
mandates the alternative interpretation in terms of a quantum
quench. The distinctive features as compared to ETH are
highlighted.
/136/
Date: Wednesday 2013.05.22
Speaker: Prof. Michał Banaszak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Simple model of transport in biological cells
Abstract: Physical-chemical reasoning is used to demonstrate
that the sizes of both prokaryotic and eukaryotic cells are
such that they minimize the times needed for the
macromolecules to migrate throughout the cells and
interact/react with one another. This conclusion does not
depend on a particular form of the crowded-medium diffusion
model, as thus points toward a potential optimization
principle of cellular organisms. In eukaryotes, size
optimality renders the diffusive transport as efficient as
active transport - in this way, the cells can conserve
energetic resources that would otherwise be expended in
active transport.
/135/
Date: Wednesday 2013.05.15
Speaker: Dr Barbora Lemrová
Affiliation: Department of Organic Chemistry, Palacký
University, Olomouc, Czech Republic
Title: BIOMEDREG - bio-sciences centre in Olomouc
Abstract: Biomedreg is a collaboration project to join several
bio-sciences groups. This centre provides research activities
ranging from organic synthesis to medicinal research.
/134/
Date: Wednesday 2013.05.15, 12:30
Speaker: Dr Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký University
and Institute of Physics of Academy of Sciences of the Czech
Republic, Faculty of Science, Palacký University, Olomouc, Czech
Republic
Title: Regional Centre of Advanced Technologies and Materials
Abstract: The talk will provide an overview of the RCPTM - a
regional centre of scientific collaboration across various natural
sciences (physics, chemistry, nanomaterials). The capabilities in
contract and collaboration research will be presented.
/133/
Date: Wednesday, 2013.5.8
Speaker: Prof. Adekunle Adeyeye
Affiliation: Departament of Electrical Computer Engineering,
National University of Singapore, Singapore.
Title: Artificial Ferromagnetic Nanostructures: An Experimental
Platform for Magnonics
Abstract: Artificial ferromagnetic nanostructures with periodic
lateral contrasts in magnetization are known as “magnonic
crystals” (MCs), conceived as the magnetic analogue of photonic
crystals. Recently, there is growing interest in the fundamental
understanding of the spin wave propagation in MCs because of their
huge potential in a wide range of applications such as microwave
resonators, filters and spin wave logic devices. With advances in
controlled nanofabrication techniques, it is now possible to
synthesize high-quality periodic bi-component magnetic
nanostructures with precisely controlled dimensions. The band
spectrum of MCs consists of allowed states magnonic bands and
forbidden states (magnonic gaps) that can be tuned by magnetic
fields or geometrical parameters. We have shown that MCs represent
a perfect system for studying excitations on disordered periodical
lattices because of the possibility of controlled variation in the
degree of disorder by varying the applied magnetic field [1]. We
have also demonstrated functionality of magnetic logic based on a
reconfigurable MC in the form of a meander-type ferromagnetic
nanowire [2]. A ferromagnetic resonance method employing a
microscopic coplanar waveguide was used to detect the logic state
of the structure coded in its magnetic ground state.
This talk will be divided into 3 parts: the first part will
focus on strategies we have developed for synthesizing
high-quality 1-D and 2-D MCs using deep ultra-violet
lithography technique at 248 nm exposure wavelength. Using
resolution enhancement techniques, we have fabricated arrays
of ferromagnetic nanostructures with lateral dimensions and
inter-element spacing below the conventional resolution limit
of optical lithography tools. The second part will focus on
results of our recent systematic investigation of both the
static and dynamic properties of MCs using a combination of
magneto-optical Kerr effect measurements, magnetic force
microscopy, broadband ferromagnetic resonance spectroscopy,
magneto transport measurements and micromagnetic simulations.
In the third part, the concept of binary magnetic
nanostructures will be introduced and their potential
application in magnetic logic devices demonstrated.
[1] J. Ding, M. Kostylev, and A. O. Adeyeye, Physical Review
Letters 107,047205 (2011).
[2] J. Ding, M. Kostylev, and
A. O. Adeyeye, Applied Physics Letters 100, 062401 (2012).
/132/
Date: Tuesday 2013.04.30
Speaker: Dr Karol Bartkiewicz
Affiliation: Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of
the Czech Republic, Faculty of Science, Palacký University,
Olomouc, Czech Republic
Title: Measuring nonclassical correlations of two-photon states
Abstract: The threshold between classical and nonclassical
two-qubit states is drawn at the place when these states can
no longer be described by classical correlations, i.e.,
quantum discord or entanglement appear. However, to check if
the correlations are classical (in terms of quantum discord
and entanglement) it is sufficient to witness the lack of
quantum discord because its zero value implies the lack of
entanglement. We explain how the indicator of quantum discord
introduced by Girolami and Adesso [Phys. Rev. Lett. 108,
150403 (2012)] can be practically measured in linear-optical
systems using standard beam splitters and photon detectors.
We also show how to the setup can be modified to efficiently
investigate the degree of Bell-CHSH inequality violation.
/131/
Data: Środa 2013.04.24
Prelegent: Dr Jarosław W. Kłos
Afiliacja: Zakład Fizyki Nanomateriałów, WF UAM
Tytuł: Periodyczne heterostruktury półprzewodnikowe jako aktywne
elementy ogniw słonecznych
(Semiconductor superlattices applied
to intermediate band solar cells)
Streszczenie: Periodyczne heterostruktury półprzewodnikowe są
układami z podwójną periodycznością. Periodyczność sieci
krystalicznej powoduje powstanie przerwy energetycznej (o
szerokości od ułamka eV do pojedynczych eV), która w litym
materiale wyraźnie rozdziela prawie całkowicie obsadzone pasmo
walencyjne do prawie pustego pasma przewodnictwa. Wprowadzenie
periodycznej strukturalizacji, np. poprzez wytworzenie
heterostruktury półprzewodnikowej, o okresie rzędu kilku lub
kilkudziesięciu nm prowadzi do wytworzenia miniprzerw
energetycznych w obrębie wierzchołka pasma walencyjnego i dna
pasma przewodnictwa o szerokościach istotnie mniejszych od
szerokości przerwy energetycznej litego półprzewodnika. Stany
elektronowe i dziurowe o energiach bliskich dna pasma
przewodnictwa i wierzchołkowi pasma walencyjnego mogą być opisane
w przybliżeniu kp za pomocą równania Schrodingera ze zmienną
przestrzennie masą
efektywną nośnika, odpowiednio, elektronów i dziur.
Rozdzielanie pasma przewodnictwa i pasma walencyjnego na
minipasma może zwiększyć efektywność produkcji par
elektron-dziura przy absorpcji światła słonecznego. Efekt ten
wynika z ograniczenia procesów termalizacji oraz z pojawienia
się nowych przejść pomiędzy minipasmami. Zostaną
przedstawione wyniki obliczeń teoretycznych efektywności
ogniw słonecznych działających w oparciu o dwuwymiarowe
periodyczne heterostruktury półprzewodnikowe na bazie
AsGa/AlGaAs dla różnych geometrii rozważanych układów.
/130/
Data: Środa 2013.04.17
Prelegent: Prof. Maciej Błaszak
Afiliacja: Zakład Fizyki Matematycznej (Mathematical Physics
Division), WF UAM
Tytuł: Jak kanonicznie kwantować mechanikę hamiltonowską we
współrzędnych krzywoliniowych?
(Canonical quantization of
Hamiltonian mechanics in curvilinear coordinates)
Streszczenie: Prezentowana jest niezmiennicza procedura kwantyzacji
na przestrzeni fazowej oraz jej niezmiennicza reprezentacja
operatorowa w przestrzeni Hilberta nad płaską przestrzenią
konfiguracyjną. W konsekwencji pokazana jest konstrukcja
poprawnych operatorów położenia i pędu dla kanonicznych zmiennych
krzywoliniowych oraz ich odpowiedni porządek w hamiltonianie.
/129/
Date: Friday 2013.4.12
Speaker: Prof. Jan Peřina Jr
Coauthors: O. Haderka, M. Hamar, and V. Michalek
Affiliation: RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Science of
the Czech Republic, Faculty of Science, Palacký University,
17. listopadu 12, 77146 Olomouc, Czech Republic
Title: Measurement of photon-number distributions of twin beams
and their applications. Generation of sub-Poissonian light.
Abstract: Determination of photon-number statistics [1,2] of
twin beams based on the measurement of photocount statistics
by an iCCD camera is discussed. The approach based on the
superposition of signal and noise [3] applied to paired
fields is analyzed in detail and compared with that based on
the method of maximum likelihood. Advantages of the use of an
iCCD camera as well as limitations are mentioned [4].
A method for the determination of absolute quantum detection
efficiency based on the measurement of photocount statistics
of twin beams is suggested [5]. The measured histograms of
joint signal-idler photocount statistics allow to eliminate
an additional noise superimposed on an ideal calibration
field composed of only photon pairs. This makes the method
superior above others presently used [6]. Values of the
inquired quantum detection efficiencies in the signal- and
idler-field paths are derived from the first- and
second-order experimental photocount moments combined with
the method of least-square declinations from the experimental
histogram.
Post-selection from twin beams is used to generate
conditional sub-Poissonian light with Fano factors up to 0.62
using the iCCD camera. Possibilities as well as limitations
of this approach are analyzed.
References:
[1] O. Haderka, J. Peřina Jr., M. Hamar, and J. Peřina, Phys. Rev.
A 71, 033815 (2005).
[2] J. Peřina Jr., O. Haderka, V. Michalek, and M. Hamar, Phys.
Rev. A 87, 022108 (2013).
[3] J. Peřina and J. Křepelka, J. Opt. B: Quant. Semiclass. Opt.
7, 246 (2005).
[4] J. Peřina Jr., O. Haderka, M. Hamar, and V. Michalek, Phys.
Rev. A 85, 023816 (2012).
[5] J. Peřina Jr., O. Haderka, M. Hamar, and V. Michalek, Opt.
Lett. 37, 2475 (2012).
[6] G. Brida, I. P. Degiovanni, M.
Genovese, M. L. Rastello, and I. R. Berchera, Opt. Express 18,
20572 (2010).
/128/
Date: Wednesday, 2013.4.10
Speaker: B.Sc. Adam Ścibior
Affiliation: University of Cambridge, UK.
Title: The physics of information processing
Abstract: This talk will feature some classical results in
the physical theory of information processing. First we'll
take a look at a model of computation based on irreversible
laws of macroscopic physics. We'll investigate its
relationship with entropy and obtain the famous Landauer's
principle. We'll further see how this principle limits the
power of our computers and how it deals with the Maxwell
demon. Later we'll consider why and how to build a model of
computation based on reversible laws of microscopic physics.
/127/
Date: Wednesday 2013.03.20
Speaker: Dr Dheeraj Kumar
Affiliation: Condensed Matter Physics and Material Sciences,
S. N. Bose National Centre for Basic Sciences, Sector-III,
Block - JD, Salt Lake, Kolkata - 700098
Title: Numerical Calculations Involving Spin-Wave Dynamics in One-
and Two-Dimensional Magnonic Crystals
Abstract: Numerical methods, which analyse the output of
micro-magnetic simulations can be employed to extract
desirable information. The presentation will discuss what
information is usually required from theoretical and
experimental aspects and how one can go about obtaining them.
Apart from visualizing the evolution of magnetization with
time in these mediums, methods to plot spin-wave power in
frequency and wavevector domain shall also be discussed.
/126/
Date: Wednesday 2013.03.13
Speaker: Prof. Piotr Tomczak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Quantum dimer model on Sierpiński gasket lattice
Abstract: The properties of quantum dimer model are
investigated on 42-site Sierpiński lattice. This is a
self-similar lattice with, to some extend, the corner-sharing
triangles. It is interesting that the entropy of dimer
coverings of Sierpiński lattice is the same as that for the
kagomé lattice (1/3 ln 2). We demonstrate that the quantum
dimer model has short-range dimer-dimer correlations and
gapped dimer-liquid phase with topological degeneracy. A full
spectrum of a dimer liquid is obtained.
/125/
Date: Friday, 2013.3.8, 10:00
Speaker: Prof. Sergey A. Nikitov
Affiliation: Vice-director of Kotel’nikov Institute of
Radioengineering and Electronics of Russian Academy of
Sciences, Moscow, Russia; Corresponding Member of RAS
Title: Institute of Radioengineering and Electronics of RAS. New
trends in analogue electronics.
/124/
Date: Friday, 2013.3.1
Speaker: Dr Krzysztof Lebecki
Affiliation: Fachbereich Physik, Universitat Konstanz,
Konstanz, Germany; home page
Title: Temperature effects in magnetism in the nanoscale
Abstract: Usually, magnetic behavior in the nanoscale is
described by the Landau-Schlitz-Gilbert equation. This
enables us, for instance, to model and understand
time-related issues, like: precession, or magnetization
switching. In my talk I will shortly describe this equation
and its importance. Then, I will speak about temperature, its
influence, and how it can be included into the model. I will
describe the problem from two perspectives. There exists
namely an atomistic approach, where every single spin is
modeled. For larger systems we use continuum
theory-micromagnetism. This will lead me to the recently
proposed Landau-Schlitz-Bloch equation. The talk will be
supported with results of numerical simulations.
/123/
Date: Wednesday 2013.2.6
Speaker: Dr Magdalena Stobińska
Affiliation: Institute of Theoretical Physics, Polish Academy
of Sciences and Institute of Theoretical Physics and
Astrophysics, University of Gdansk
Title: Entanglement Witnesses and Measures for Bright Squeezed
Vacuum
Abstract: Quantum entanglement is a fascinating phenomenon,
especially if it is observed at the macroscopic scale.
Importantly, macroscopic quantum correlations can be revealed
only by accurate measurement outcomes and strategies. Here,
we formulate feasible entanglement witnesses for bright
squeezed vacuum in the form of the macroscopically populated
polarization triplet Bell states. Their testing involves
efficient photodetection and the measurement of the Stokes
operators variances. We also calculate the measures of
entanglement for these states such as the Schmidt number and
the logarithmic negativity. Our results show that the bright
squeezed vacuum degree of polarization entanglement scales as
the mean photon number squared. We analyze the applicability
of an operational analog of the Schmidt number.
Reference: Phys. Rev. A 86, 022323 (2012)
/122/
Date: Wednesday 2013.1.23
Speaker: Prof. Anirban Pathak
Affiliation: Department of Physics, Jaypee Institute of
Information Technology (Deemed University), Noida, India.
Temporarily at RCPTM, Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Science of
the Czech Republic, Faculty of Science, Palacký University,
Olomouc, Czech Republic.
Title: Secure quantum communication using arbitrary orthogonal
multi-particle quantum states
Abstract: It is shown that maximally efficient protocols for
secure direct quantum communications can be constructed using
any arbitrary orthogonal basis. This establishes that no set
of quantum states (e.g. GHZ states, W states, Brown states or
Cluster states) has an advantage over the others, barring the
relative difficulty in physical implementation. This provides
a wide choice of states for experimental realization of
direct secure quantum communication protocols. We have also
shown that this protocol can be generalized to a completely
orthogonal state based protocol of Goldenberg-Vaidman (GV)
type. The security of these protocols essentially arises from
duality and monogamy of entanglement. This stands in contrast
to protocols that employ non-orthogonal states, like
Bennett-Brassard 1984 (BB84), where the security essentially
comes from non-commutativity in the observable algebra. This
observation is exploited to classify the quantum
communication protocols into two broad (but not exclusive)
classes: A) protocols based on conjugate coding, which
require the non-commutative structure of the physical theory;
and B) superposition-based protocols, where security arises
from non-realism and linearity.
/121/
Date: Wednesday 2013.1.16
Speaker: B.Sc. Karol Nowacki
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Cryptography in classical antiquity
Abstract: The ancient Greeks and Romans used several methods
of hiding secret messages written in plaintext, but seldom
had recourse to cryptography in the proper sense. Two
examples of its application - Caesar's substitution cipher
and a Spartan transposition ciphering device - are discussed
based on accounts by Aulus Gellius and other authors.
/120/
Data: Środa 2013.1.9
Prelegent: Prof. Grzegorz Wrochna
Afiliacja: Dyrektor Narodowego Centrum Badań Jądrowych w
Świerku
Tytuł: Energetyka jądrowa - nie chcemy, ale musimy?
Streszczenie: Energetyka jądrowa (EJ) budzi wiele kontrowersji, a
powszechna wiedza na jej temat zdominowana jest przez mity i
nieporozumienia. Seminarium będzie próbą odpowiedzi na pytania: EJ
na świecie po Fukushimie: regres czy renesans? Dlaczego Niemcy
rezygnują z EJ? Czy EJ jest potrzebna Polsce? Program Polskiej EJ:
jakim cudem jest realizowany, skoro nie jest zatwierdzony?
/119/
Data: Środa 2012.12.19
Prelegent: Prof. Marek Wolf
Afiliacja: Uniwersytet Kardynała Stefana Wyszyńskiego
Tytuł: Hipoteza Riemanna oczami fizyka
Streszczenie: Hipoteza Riemanna (RH) mówi o położeniu na płaszczyźnie
zespolonej nietrywialnych zer funkcji dzeta dzeta(s) Riemanna.
Jest ona jednym z najbardziej znanych nierozwiązanych problemów w
matematyce. Po sformułowaniu hipotezy Riemanna kilka minut
poświęcę anatomii dzety Riemanna. Zasadnicza część wykładu będzie
poświęcona omówieniu związków RH z fizyką: Twierdzenie Woronina i
fraktalność dzety(s). Elektromechaniczny układ van der Pola.
Przypuszczenie Polya'i-Hilberta, korelacje zer dzety: praca
Montgomerego, macierze losowe, hamiltonian Okubo, Berry: H=xp.
Związki z chaosem kwantowym. Modele Isinga i RH. Bilardy i RH.
Ruchy losowe i RH.
/118/
Date: Wednesday 2012.12.12
Speaker: Prof. Kostyantyn Gusliyenko
Affiliation: Ikerbasque Research Professor, Departamento de
Física de Materiales, Universidad del País Vasco, UPV/EHU,
San Sebastian, SPAIN.
Title: Review of spin dynamics in the vortex state magnetic dots
and nanopillars
Abstract: Fundamental understanding of spin dynamics and
reversal in a system with a reduced dimensionality is
essential in the future advancements of nanomagnetism and
spintronics. Thus, it becomes important to explore the spin
excitations in sub-micron magnetic particles such as dots.
For mesoscopic and nanoscale sizes of dots, non-uniform
magnetization distributions with zero remanence ("vortex"
states) are often observed at equilibrium [1]. The magnetic
vortex with the in-plane curling magnetization and the
out-of-plane magnetization at the core is the simplest
topologically non-trivial ground state in ferromagnetic dots.
The vortex states are stable within a wide range of dot sizes
from a few tens of nm up to a few tens of microns. Vortex
related phenomena offer insight into spin dynamics on a
fundamental level, and also govern magnetization reversal. In
this talk, I will present a review of calculations and
measurements of the spin excitations in the vortex ground
state of soft magnetic dots. The spectrum of spin excitations
consists of a low-frequency gyrotropic (sub-GHz range) mode
describing precessional motion of the vortex core and
high-frequency modes describing spin excitations of the
vortex planar part. Nontrivial spin dynamic properties, such
as magnetic vortex core (VC) polarization reversal driven by
small-amplitude, oscillating (pulse) magnetic fields or spin
polarized currents, were observed [2]. Special interest in
the vortex dynamics is inspired by the possibility of easy
and controllable dynamical switching of the VC magnetization
direction (polarization). The dynamical origin of the VC
polarization reversal will be considered. We derived a phase
diagram of the VC reversal and its switching time with
respect to both the driving field strength and frequency. The
interaction of high frequency azimuthal spin waves with the
moving VC [3] and their influence on the VC motion will be
discussed. There is a giant frequency splitting of the spin
waves having non-zero overlapping with the vortex mode as
well as a finite vortex mass of dynamical origin. We
calculated also the main dynamic parameters of the spin
polarized current induced magnetic vortex oscillations in
nanopillars, such as the range of current density, where the
vortex steady oscillation state exists, the oscillation
frequency and VC orbit radius [4].
References:
[1] K.Y. Guslienko, J. Nanosci. Nanotechn. 8, 2745 (2008).
[2] B. Van Waeyenberge et al., Nature 444, 461 (2006); K. Yamada
et al., Nature Materials 6, 269 (2007).
[3] K.Y. Guslienko et al., Phys. Rev. Lett. 101, 247203 (2008);
Phys. Rev. B 81, 014414 (2010).
[4] K.Y. Guslienko et al., J. Phys.: Conf. Ser. 292, 012006
(2011).
/117/
Date: Wednesday 2012.11.28
Speaker: M.Sc. T. Kendziorczyk
Coauthor: T. Kuhn
Affiliation: Institut für Festkörpertheorie, Universität
Münster, 48149 Münster, Germany
Title: Micromagnetic simulation of spin torque nano-oscillators
Abstract: It has been predicted theoretically and observed
experimentally that a direct current traversing a magnetic
multilayer exerts a spin torque on the magnetic system which can
compensate the natural damping and lead to self-sustaining
magnetic oscillations in the GHz range. Due to the easy frequency
tunability of the spin torque nano-oscillators (STNOs) this effect
has great potential for the construction of nanosized microwave
gen- erators. The main problem which has to be solved for future
applications is the low output power of a single STNO. Some
experiments have already been performed which show that it is
possible to synchronize two STNOs. The output power for N
synchronized STNOs could in principle scale with N2. However,
in order to construct larger arrays of STNOs a good knowledge
about the interaction mechanism between them is indispensable,
which can be obtained by means of micromagnetic simulations. This
talk will give a general overview of the magnetization dynamics of
an extended thin magnetic film excited by a direct current through
a point contact. The oscillation below the point contact can
excite propagating spin waves which provide an important mechanism
for the interaction between STNOs. We will present micromagnetic
simulation results concerning the synchronization of two STNOs
which show that there can exist several different synchronized
states, whose dynamics are determined by the characteristics of
the involved spin waves.
/116/
Date: Wednesday 2012.11.28
Speaker: M.Sc. J. Hüser
Coauthors: T. Kendziorczyk and T. Kuhn
Affiliation: Institut für Festkörpertheorie, Universität
Münster, 48149 Münster, Germany
Title: Effects of the lattice discreteness on the spin wave
dispersion in ferromagnetic thin films
Abstract: Spin wave dispersion relations in ferromagnetic
thin films are often calculated within a continuum model
based on the Landau-Lifshitz equation thereby neglecting the
underlying lattice structure in real materials. In this talk
we present and analyze some differences between the spin wave
modes obtained in a lattice model and the well known results
of the continuum model. For this purpose we calculate the
spin wave dispersion with a discrete model consisting of
classical spins which are stacked on a cubic lattice and
interact via exchange and dipolar forces. In the case of
magnetostatic modes, the discrete model yields new
qualitative features in comparison with the results of Damon
and Eshbach. We observe several surface modes and the
degeneracy of the spin waves which propagate perpendicularly
to the applied magnetic field is lifted. We also show that
the dipolar-exchange modes are strongly influenced by the
boundary conditions in ultra-thin films and undergo a
frequency upshift. Finally, we compare the 2d-limit of the
continuum model with the case of a single layer in the
discrete model.
/115/
Date: Wednesday 2012.11.7
Speaker: Prof. Henryk Drozdowski
Affiliation: Optics Division, Physics Faculty, AMU
Title: New outlook on molecular liquids by X-ray diffraction
Abstract: Knowledge of the structure, molecular correlations
and mechanisms of structural processes taking place in
liquids are of fundamental importance for understanding of
their physical and chemical properties. X-Ray diffraction
studies of liquids open a possibility of finding relations
between their structures and properties. Liquids have been
divided into certain classes (homologue series) according to
certain properties. The lecture is concerned with
presentation of application of X-Ray diffraction method to
investigation of intra- and intermolecular interactions and
close-range structure in selected complex liquids. X-ray
structural study brings information on the types of molecular
associations contributing to determination of the liquid
nature and mechanisms of processes taking place in it. The
close-range ordering is related to the mode of packing of
molecules in the liquid. According to molecules in liquid
have at their disposal 35% of free space. Structure of
liquid can be described by the radial distribution function
(RDF). This function permits determination of such parameters
as the sphere radii, coordination numbers and degree of
ordering. The close-ordering range determined in the liquids
studied by the WAXS method is about 2 nm.
/114/
Date: Wednesday 2012.10.31
Speaker: Dr hab. Genowefa Ślósarek
Affiliation: Molecular Biophysics Division, Physics Faculty, AMU
Title: Współczesna rewolucja naukowa na pograniczu fizyki i
biologii
Abstract: Koniec XX wieku przyniósł wielkie zmiany w
paradygmatach fizyki molekularnej i biologii. Doszło do
powstania nowych dziedzin nauki - nanotechnologii i biologii
systemowej. Są to zupełnie rozdzielne dziedziny badań. W
konsekwencji trudno jest obecnie jednoznacznie określić
interdyscyplinarny kierunek badań, jakim była biofizyka.
/113/
Date: Wednesday 2012.10.24
Speaker: Dr Marcin Ziółek
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Fotoogniwa barwnikowe badane metodami spektroskopii
laserowej
Abstract: Fotoogniwa barwnikowe (DSSC: Dye-Sensitized Solar
Cells), należą do nowej, obiecującej generacji ogniw słonecznych,
w których podstawą funkcjonowania jest oddziaływanie barwników
organicznych z warstwami nanocząstek tlenków metali (najczęściej
tlenku tytanu). Fotogniwa barwnikowe zostały po raz pierwszy
zaproponowane stosunkowo niedawno, w pionierskiej pracy w Nature w
1991 r. Ich obecna sprawność może przekraczać 12%, a znacznie
mniejsze koszty produkcji oraz lepsza wydajność w warunkach
umiarkowanego i słabego oświetlenia (wewnątrz pomieszczeń i w
strefie klimatycznej, w której leży nasz kraj) powodują, że stały
się one potencjalną alternatywą dla dotychczasowej generacji
fotoogniw krzemowych. O wysokim i realnym znaczeniu fotoogniw
barwnikowych świadczy lawinowo wzrastająca liczba publikacji i
patentów na ich temat oraz wiele prestiżowych nagród naukowych
przyznanych w ostatnich latach ich głównemu twórcy, Michealowi
Grätzelowi. Separacja ładunku w fotoogniwach barwnikowych decyduje
o ogólnej sprawności ogniwa i odbywa się w kilku procesach
(wstrzykiwanie elektronu z barwnika do nanocząstki, regeneracja
barwnika, transport ładunku przez nanocząstki), których skala
czasowa rozciąga się od dziesiątek femtosekund do setek
milisekund. Poznańie cząstkowych wydajności poszczególnych
procesów jest możliwe za pomocą technik czasowo-rozdzielczej
absorpcyjnej i emisyjnej spektroskopii laserowej w świetle
widzialnym i podczerwieni. Podczas seminarium omówione zostaną
najnowsze modele opisujące wspomniane procesy i zaprezentowane
będą wyniki badań fotoogniw barwnikowych metodami spektroskopii
laserowej, w których w ostatnich kilku miesiącach autor brał
udział. Znaczna część badań została przeprowadzona na Wydziale
Fizyki UAM.
/112/
Date: Thursday 2012.10.18
Speaker: Dr Antonín Černoch
Affiliation: Institute of Physics of Academy of Science of
the Czech Republic, Joint Laboratory of Optics of PU and IP
AS CR, Olomouc, Czech Republic
Title: Single photon detection in Olomouc
Abstract: The talk presents several devices capable of
detection of ultra-weak light signals. The main technological
aspects and limitations of these devices are discussed with
emphasis on possible usage in quantum optical experiments.
/111/
Date: Thursday 2012.10.18
Speaker: Dr Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of
the Czech Republic, Faculty of Science, Palacký University,
Olomouc, Czech Republic
Title: Optimal linear-optical tunable controlled phase gate and
related research
Abstract: Controlled phase gate is one of the fundamental
building blocks of quantum information devices. This talk
presents our experimental implementation of such device and
related research.
/110/
Date: Thursday 2012.10.18
Speaker: Prof. Konrad Banaszek
Affiliation: Institute of Theoretical Physics, Department of
Quantum Optics and Atomic Physics, Faculty of Physics,
University of Warsaw
Title: Entanglement-based effects in two-photon propagation
Abstract: Radiation generated in spontaneous parametric
down-conversion exhibits a number of interesting features.
One of them is the phenomenon of non-local dispersion
cancellation, in which strong temporal correlations between
photon pairs are preserved despite propagation through
dispersive media with group velocity dispersion coefficients
of equal strength and opposite signs. An intriguing question
is whether such features can be reproduced with classical
radiation. In the case of non-local dispersion cancellation,
an analogous effect can be shown to occur also for Gaussian
mixtures of coherent states, but at the cost of introducing a
uniform background of coincidence counts with a comparable
magnitude. We present here a simple variance-based criterion
identifying a feature of non-local dispersion cancellation
that critically depends on the presence of entanglement in
the propagating light. Analogous analysis can be applied also
to directional correlations in free-space propagation.
/109/
Date: Thursday 2012.10.18
Speaker: Dr Karol Bartkiewicz
Affiliation: Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of
the Czech Republic, Faculty of Science, Palacký University,
Olomouc, Czech Republic
Title: Experimental quantum cloning for hacking quantum-key
distribution protocols
Abstract: We describe a proof-of-principle experiment which
shows that quantum cloning can be used for hacking quantum
key distribution protocols. We analyze the conditions under
which the cloning attack is successful and obtain the
corresponding error rates.
/108/
Date: Thursday 2012.10.18
Speaker: Dr Monika Bartkowiak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Amplification of Kerr nonlinearity and its application for
deterministic entangling gates at the single-photon level
Abstract: An alternative approach to implement quantum
entangling gates to the well-known linear-optical one is
using nonlinear materials for deterministic nonlinear photon
interactions. However only small conditional phase shift
induced by a few photons in the Kerr nonlinearity was
successfully measured. We show how to improve the phase-shift
obtained for two single-photon states in the cross-Kerr
interaction.
/107/
Date: Thursday 2012.10.18
Speaker: Dr Anna Kowalewska-Kudłaszyk
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Kerr couplers as nonlinear quantum scissors -
entanglement creation and decay
Abstract: Various types of decay for entanglement obtained
within nonlinear quantum scissors systems are discussed.
Conditions for observing entanglement death or its revival
are presented.
/106/
Date: Thursday 2012.10.18
Speaker: Prof. Wiesław Leoński
Affiliation: Quantum Optics and Engineering Division,
Institute of Physics, University of Zielona Góra
Title: Quantum states engineering - nonlinear quantum scissors
Abstract: Several models involving nonlinear quantum
Kerr-like oscillators are presented. Such models referred to
as nonlinear quantum scissors can lead to
finite-dimensional states generation, including maximally
entangled ones.
/105/
Date: Wednesday 2012.10.17
Speaker: Dr Michał Berent
Coauthors: Andon A. Rangelov and Nikolay V. Vitanov
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Broadband Faraday isolator
Abstract: Drawing on an analogy with the powerful technique
of composite pulses in quantum optics and polarization optics
we present a broadband optical diode (optical isolator) made
of a sequence of ordinary 45° Faraday rotators sandwiched
with quarter-wave plates rotated at the specific angles with
respect to their fast polarization axes.
/104/
Date: Wednesday 2012.10.17
Speaker: Dr Piotr Trocha
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Spin and charge thermoelectric effects in a double quantum
dot system
Abstract: Thermoelectric effects in a double quantum dot
system coupled to external magnetic/nonmagneticleads are
investigated theoretically. The basic thermoelectric
transport characteristics, like thermopower, electronic
contribution to heat conductance, and the corresponding
figure of merit, have been calculated in terms of the linear
response theory and Green function formalism in the
Hartree-Fock approximation for Coulomb interactions. An
enhancement of the thermal efficiency (figure of merit ZT)
due to Coulomb blockade has been found. The magnitude of ZT
is further considerably enhanced by quantum interference
effects. The influence of spin-dependent transport on the
thermoelectric effects (especially on Seebeck and spin
Seebeck effects) is also analyzed.
/103/
Date: Wednesday 2012.10.17
Speaker: Prof. Piotr Tomczak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Entanglement in Quantum Spin Systems: RVB Approach
Abstract: Recently proposed estimators for entanglement
entropy in quantum spin systems in resonating valence bond
(RVB) basis are reviewed. Some of them may be effectively
calculated by using Monte Carlo techniques. Additionally
properties of entanglement spectrum of small systems are
presented in position and momentum space and their relation
to topologically ordered states is discussed. An attempt to
calculate such a spectrum of small spin systems in RVB basis
is reported. A possibility of finding the topological order
in quantum spin systems using RVB basis is discussed.
/102/
Date: Wednesday 2012.10.17
Speaker: B.Sc. Marcin Karczewski
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: An algorithm for characterizing SLOCC classes of
multiparticle entanglement
Abstract: A primer on how geometric invariant theory and
momentum map geometry could be used to effectively find all
stochastic local operations and classical communication
(SLOCC) classes of pure states.
/101/
Date: Wednesday 2012.10.17
Speaker: M.Sc. Jan Tuziemski
Affiliation: Faculty of Applied Physics and Mathematics,
Technical University of Gdańsk
Title: Novel property of private states and its application
Abstract: Quantum bipartite states with the direct
accessible, ideal cryptographic key are known as private
states. In this talk we will present a novel property, namely
the invariance of distillable key under rotations around
private axis in Devetak-Winter protocol, for general private
states. Its application to the problem of searching optimal
measurement basis for a given private state will be
demonstrated. We will also provide results concerning error
estimation of the proposed procedure.
Seminar language: English
/100/
Date: Wednesday 2012.10.17
Speaker: M.Sc. Joanna Pietraszewicz
Affiliation: Institute of Physics, Polish Academy of Sciences
(PAN), Warsaw
Title: Anharmonicity vs. higher orbital states in the optical
lattices
Abstract: It is known that dipolar interactions in the
presence of a resonant magnetic field can transfer atoms to
higher excited states with non zero angular momentum
(Einstein-de Haase effect). We investigate how this effect is
modified by the lattice potential. In particular we explain
in details the role of anharmonicity and anisotropy of a
single lattice site.
Seminar language: English
/99/
Date: Wednesday 2012.10.17
Speaker: Dr Grzegorz Chimczak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Improving fidelity in atomic-state teleportation via
non-maximally-entangled states
Abstract: The talk shows that non-maximally entangled states
can be better for atomic state teleportation performed via
cavity decay. The destructive influence of cavity decay on
the fidelity can be minimized by using in the teleportation
the non-maximally entangled states instead of the maximally
entangled state.
Seminar language: English
/98/
Date: Wednesday 2012.10.17
Speaker: B.Sc. Karol Nowacki
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Statistical testing of random number generators
Abstract: Review of statistical randomness tests and their
software implementations used to verify quality of random
number generators.
Seminar language: English
/97/
Date: Wednesday 2012.10.17
Speaker: Dr Marek Sawerwain
Affiliation: Institute of Physics, University of Zielona Góra
Title: Perfect state transfers in finite Hilbert space (for qubits
and qudits)
Abstract: The talk presents the perfect state transfer (PST)
protocols performed in 1D qubit or qudit chains. Dynamics of
transfer is determined by the XY-like Hamiltonian which will
be described by special unitary group operators SU(d).
Seminar language: English
/96/
Date: Wednesday 2012.10.17
Speaker: Prof. Andrea Lehmann-Szweykowska
Coauthors: Ryszard Wojciechowski, Michał Kurzyński
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Correlated cluster mean field theory in the hcp
compressible Ising model
Abstract: We derive an hcp compressible Ising Hamiltonian
with a spin-phonon interaction and compute the influence of
spin correlations on the empirically observed Brillouin
shift. The spin correlations are found by an Oguchi-like
method which is newly tailored variation of the
Bethe-Peierls-Weiss (BPW) approximation. In the direct space,
we consider a cluster consisting of a central spin and its 12
nearest neighbours. Each of the 12 nn pairs, consisting of
the central spin and, in turn, all the neighbours , is
treated exactly (Oguchi method) while the influence of the
remaining spins is replaced by an effective field. In the
present approach, the latter is not calculated
self-consistently, but substituted by that found in the
conventional MFA. In the reciprocal lattice, after the
Fourier transformation, we finally arrive at the spin
correlation which is temperature and wave-vector dependant.
The result remains valid both in the ordered and disordered
phases. In the ordered phase, the molecular-field
approximation is extended to the static soliton theory.
Seminar language: English
/95/
Date: Wednesday 2012.10.17
Speaker: Dr hab. Jan Soubusta
Affiliation: Institute of Physics of Academy of Science of
the Czech Republic, Joint Laboratory of Optics of PU and IP
AS CR, Olomouc, Czech Republic
Title: Spatial and spectral properties of the pulsed
second-harmonic generation in a PP-KTP waveguide
Abstract: Spatial and spectral properties of the pulsed
second harmonic generation in a periodically-poled KTP
waveguide are analyzed. Experimental results are interpreted
using a model based on finite elements method.
Seminar language: English
/94/
Date: Wednesday 2012.10.17
Speaker: Dr hab. Krzysztof Gibasiewicz
Affiliation: Molecular Biophysics Division, Physics Faculty, AMU
Title: Influence of protein dynamics on intraprotein electron
transfer in photosynthetic reaction centers
Abstract: Photosynthetic reaction centers are pigment-protein
complexes containing a chain of electron transfer carriers. A
linear electron transfer between these carriers occurs on a
wide time-scale spanning from picoseconds to microseconds
depending on particular step of the transfer. In the talk,
results of experimental studies of one particular step of
this electron transfer will be shown. Multiphasic kinetics of
this reaction is interpreted in terms of a model in which
protein dynamically modulates the rate of the electron
transfer with characteristic lifetimes of ∼ 1 and
∼ 10 ns.
Seminar language: English
/93/
Date: Wednesday 2012.10.17
Speaker: Dr Barbora Lemrová
Affiliation: Department of Organic Chemistry, Palacký
University, Olomouc, Czech Republic
Title: Solid phase synthesis of potentially biologically active
compounds
Abstract: The talk presents the technique of the so-called
solid phase synthesis of organic molecules. Its application
on synthesis of compounds with potential biological activity
is discussed with emphasis on current research at the
Department of Organic Chemistry of Palacký University in
Olomouc.
Seminar language: English
/92/
Date: Tuesday 2012.10.16
Speaker: Dr Jan Milewski
Affiliation: Institute of Mathematics, Poznań University of
Technology, Poznań
Title: Anyonic harmonics and their Hodge structure deformation
Abstract: The space of anyonic harmonic function on a plane
admits a deformed Hodge structure. The deformation of the
Hodge structure is connected with the fractional statistics.
The parameters of the structure are quantum numbers of the
system.
Seminar language: English
/91/
Date: Tuesday 2012.10.16
Speaker: Dr Tomasz Polak
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Dirac like physics in optical lattices
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Abstract: This talk presents an elegant concept of the
effective mass theory applied to the neutral bosons confined
in two-dimensional square lattice under synthetic magnetic
field. Analytically calculated band structure allows to
predict the existence of the massless particles with neutrino
like dispersion relation located in the particular points of
the momentum space. It will be shown that the Dirac cones
contain massless particles whose positions and velocities can
be tuned by the external magnetic field giving rise to the
exotic properties. The presence of the Hofstadter spectrum in
the strongly interacting system of bosons reveals some
unexpected behavior of the local effective mass dependence.
Seminar language: English
/90/
Date: Tuesday 2012.10.16
Speaker: Dr Przemysław Grzybowski
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Hubbard-I approach to the Mott transition
Abstract: We analyse the Hubbard model with correlated
hopping, at the double occupancy conservation symmetry point,
using Hubbard-I approach which describes fractionalised
electrons quasiparticles. We obtain description of Mott
transitions and the surrounding extremely correlated quantum
liquids. The calculations may be relevant for future
experiments on optical lattices.
Seminar language: English
/89/
Date: Tuesday 2012.10.16
Speaker: Dr Tomasz Sowiński
Affiliation: Institute of Physics, Polish Academy of Sciences
(PAN), Warsaw
Title: Dipolar molecules in optical lattices
Abstract: We study the extended Bose-Hubbard model describing
an ultracold gas of dipolar molecules in an optical lattice,
taking into account all on-site and nearest-neighbor
interactions, including occupation-dependent tunneling and
pair tunneling terms. We show that these terms can destroy
insulating phases and lead to novel quantum phases.
Seminar language: English
/88/
Date: Tuesday 2012.10.16
Speaker: Dr Antonín Černoch
Affiliation: Institute of Physics of Academy of Science of
the Czech Republic, Joint Laboratory of Optics of PU and IP
AS CR, Olomouc, Czech Republic
Title: Experimental implementations of quantum cloners
Abstract: Review of several experimental implementations of
qubit cloners implemented in the Joint Laboratory of Optics
in Olomouc is presented. Quality of various implementations
is discussed based on obtained clones fidelity.
Seminar language: English
/87/
Date: Tuesday 2012.10.16
Speaker: Dr hab. Jan Soubusta
Affiliation: Institute of Physics of Academy of Science of
the Czech Republic, Joint Laboratory of Optics of PU and IP
AS CR, Olomouc, Czech Republic
Title: Experimental implementations of linear-optical quantum
devices
Abstract: This review talk presents several linear-optical
quantum devices suitable for discrete variables quantum
information processing. The devices make use of single and
bi-photon interference in both bulk and fibre optical
setups.
Seminar language: English
/86/
Date: Tuesday 2012.10.16
Speaker: Dr Piotr Deuar
Affiliation: Institute of Physics, Polish Academy of Sciences
(PAN), Warsaw
Title: Nonclassical atom pairs obtained from supersonic collisions
of Bose-Einstein condensates
Abstract: Correlated atom pairs are scattered from colliding
Bose-Einstein condensates by a process akin to parametric
down conversion. I will describe an experiment and its
numerical simulation that have shown number-difference
squeezing and a violation of the Cauchy-Schwartz inequality.
The long term goal is to test Bell inequalities with
spatially separated massive particles.
Seminar language: English
/85/
Date: Tuesday 2012.10.16
Speaker: Prof. Tadeusz Lulek
Affiliation: Mathematical Physics Division, Physics Faculty, AMU
Title: Galois qubits and Bethe Ansatz
Abstract: Implementation of an arithmetic qubit on the basis
of exact Bethe Ansatz eigenstates of a Heisenberg magnetic
ring is proposed. It bases on the Galois number field of an
appropriate finite extension of rationals.
Seminar language: English
/84/
Date: Tuesday 2012.10.16
Speaker: Dr Karel Lemr
Affiliation: Joint Laboratory of Optics of Palacký
University and Institute of Physics of Academy of Sciences of
the Czech Republic, Faculty of Science, Palacký University,
Olomouc, Czech Republic
Title: Quantum information in the Joint Laboratory of Optics -
last three years of photon pairs
Abstract: This talk reviews recent experimental activities in
the quantum information processing with linear-optics. The
most important results over the past three years are
presented.
Seminar language: English
/83/
Date: Tuesday 2012.10.16
Speaker: Prof. Paweł Horodecki
Affiliation: Faculty of Applied Physics and Mathematics,
Technical University of Gdańsk
Title: Quantum privacy witness
Abstract: Quantum private states are the states that
represent perfectly secure bits of secret key. It is known
that among quantum private states that are ones that are not
maximally entangled. In those cases secret key extraction
goes beyond entanglement distillation scheme. The
construction of simple observable called quantum privacy
witness which allows to correctly detect and qualitatively
estimate privacy will be presented. In some cases the
observable is experimentally very friendly still providing
useful lower bound for secret key entanglement measure K
beyond entanglement distillation regime.
Seminar language: English
/82/
Date: Tuesday 2012.10.16
Speaker: Prof. Ryszard Tanaś
Title: Correlations in a two-atom system
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Abstract: Evolution of the two-atom system driven by the
resonant laser field is considered. It is shown that the
two-photon entangled states can be generated in such a
system. The role of the dipole-dipole interaction in
generating of quantum correlations is discussed. The
condition for obtaining steady-state entanglement is given
and the time evolution of the quantum correlations is
presented.
Seminar language: English
/81/
Date: Wednesday 2012.06.13
Speaker: Prof. Tadeusz Lulek
Affiliation: Mathematical Physics Division, Physics Faculty, AMU
Title: Galois theory in Bethe Ansatz: an implementation of
arithmetic qubits
Seminar language: English
/80/
Date: Wednesday 2012.06.06
Speaker: Dr hab. Wojciech Rudziński
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Andreev reflection in a hybrid magnetic tunnel junction
Seminar language: English
/79/
Date: Wednesday 2012.05.30
Speaker: Prof. Abderrazzak Douhal
Affiliation:
Facultad de Ciencias Ambientales y Bioquimica,
Universidad de Castilla-La Mancha,
Toledo, Spain (www)
Title: Interrogating Molecules Interacting With Silica-based
Materials Using Single Molecule Fluorescence Microscopy
Abstract: In this lecture, the main concepts of single
molecule fluorescence microscopy (SMS) are first explained.
Then, I will show and discuss results from my group studying
selected molecules interacting with silica based materials
where we can directly visualise the photobehavior of a single
molecule interacting with this kind of materials. We identify
the relevant populations, and assign their emission
characteristics.
Seminar language: English
/78/
Date: Wednesday 2012.05.23
Speaker: M.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Security of quantum communication vs quantum cloning
Seminar language: English
/77/
Date: Wednesday 2012.05.16
Speaker: M.Sc. Monika Bartkowiak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Optical tests of quantumness
Seminar language: English
/76/
Date: Tuesday 2012.05.08
Speaker: Prof. Grzegorz Milczarek
Affiliation: Institute of Chemistry and Technical
Electrochemistry, Poznań University of Technology
Title: From blueberries to batteries. Energy storing materials
from biomass
Reference: G. Milczarek & O. Inganäs, Science
335, 1468 (2012)
Seminar language: English
/75/
Date: Friday 2012.04.27
Speaker: Dr Azzedine Bousseksou
Affiliation: Laboratoire de Chimie de Coordination, Tulouse,
France
Title: Spin Crossover Phenomenom at Nanoscale
Abstract: [PDF]
Seminar language: English
/74/
Date: Friday 2012.04.27
Speaker: Prof. Marylise Buron
Affiliation: University Rennes 1, France
Title: Advanced photocrystallography in molecular materials
Abstract: [PDF] Photo-Induced phase transitions [1-2]
pose challenging issues to science and science-driven
technologies, the goal of which is to control with light the
cooperative switching of the macroscopic physical state of a
material. A better understanding of the mechanisms is necessary.
Photo-crystallography may be a key issue on that purpose through
the different kinds of information that can be obtained from X-Ray
diffraction [3] patterns: unit-cell geometries, average atomic
positions, symmetry-breaking and order parameter, mechanisms of
the transition (nucleation of domains versus homogeneous
transformation), coherent processes, etc … A few examples of
photo-induced transformations in charge-transfer molecular
materials [4] or spin-crossover compounds [5-6], under both
continuous or pulsed (down to femtosecond 1 fs = 10−15 s)
irradiation will be presented.
References:
[1] Cailleau H. et al., Chap. 7 in "Photoinduced Phase
Transitions", ISBN: 981-238-763-3 (2004).
[2] Cailleau H. et al., Acta Phys. Polonica A 121 297 (2012).
[3] Collet E. et al., Journal of the Jap. Phys. Soc. 75 011002
(2006).
[4] Guerin L. et al, Phys. Rev. Lett. 105 246101 (2010).
[5] Lorenc M. et al, Phys Rev. Lett. 103 028301 (2009).
[6] Buron-Le Cointe M. et al, Phys. Rev. B 85 064114 (2012).
Seminar language: English
/73/
Date: Wednesday 2012.04.25
Speaker: Dr hab. Wojciech Rudziński
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Polaronic transport through a quantum-dot-based spin-valve
device
Seminar language: English
/72/
Date: Wednesday 2012.04.18
Speaker: Dr Ravindra Chhajlany
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Quantum percolation
Seminar language: English
/71/
Date: Wednesday 2012.04.11
Speaker: Prof. Piotr Tomczak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Metoda grupy renormalizacji w fizyce klasycznej i
kwantowej
Seminar language: English
/70/
Date: Wednesday 2012.04.04
Speaker: Prof. Nataliya Dadoenkowa
Affiliation: Donetsk Physical and Technical Institute of the
NAS of Ukraine
Title: Linear and nonlinear reflection of light on realistic
interfaces of magnetic and nonmagnetic media. The effect of
strains.
Seminar language: English
/69/
Date: Wednesday 2012.03.28
Speaker: M.Sc. Yuliya Dadoenkowa
Affiliation: Donetsk Physical and Technical Institute of the
NAS of Ukraine
Title: Magneto-optical ellipsometry: Effect of the combined
nonlinear optical interaction and magneto-electric coupling
Seminar language: English
/68/
Date: Tuesday 2012.03.27
Speaker: Prof. Lianao Wu
Affiliation: IKERBASQUE of the Basque Foundation for Science
and Department of Theoretical Physics and History of Science
of the Basque Country University (EHU/UPV), Bilbao, Spain
Title: Quantum phase transitions and quantum entanglement (part
II)
Seminar language: English
/67/
Date: Tuesday 2012.03.27
Speaker: Prof. Abdellah Abdelaziz Huseen Al-Sunaidi
Affiliation: King Fahd University of Petroleum |
Minerals,
Dhahran, Saudi Arabia
Title: Investigating the Liquid-Crystalline Behavior of Rod-Coil
Copolymers Using the Dissipative Particle Dynamics Method
Seminar language: English
/66/
Date: Wednesday 2012.03.21
Speaker: Prof. Lianao Wu
Affiliation: IKERBASQUE of the Basque Foundation for Science
and Department of Theoretical Physics and History of Science
of the Basque Country University (EHU/UPV), Bilbao, Spain
Title: Nondeterministic ultrafast ground-state cooling of a
mechanical resonator
Seminar language: English
/65/
Date: Wednesday 2012.03.14
Speaker: M.Sc. Monika Bartkowiak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Universal optical quantum gates
Seminar language: English
/64/
Date: Wednesday 2012.03.07
Speaker: Prof. Michał Banaszak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Effect of Fluctuations on Order Formation in Ion-containing
Block Copolymers
Seminar language: English
/63/
Date: Wednesday 2012.02.29
Speaker: M.Sc. Waldemar Kłobus
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Quantum mechanics near closed timelike curves
Seminar language: English
/62/
Date: Wednesday 2012.02.22
Speaker: Dr Ireneusz Weymann
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: Frequency-Dependent Spin Current Noise through Correlated
Quantum Dots
Seminar language: English
/61/
Date: Wednesday 2012.02.15
Speaker: Prof. Michał Banaszak
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Great expectations: can artificial molecular machines
deliver on their promise?
Seminar language: English
/60/
Date: Wednesday 2012.02.08
Speaker: M.Sc. Mykhaylo Sokolovskyy
Affiliation: Nanomaterials Physics Division, Physics Faculty, AMU
Title: Investigation of spin dynamics in planar magnonic crystals
Seminar language: English
/59/
Date: Wednesday 2012.02.01
Speaker: Prof. Igor Lyubchanskii
Affiliation: Donetsk Physical and Technical Institute of the
National Academy of Sciences of Ukraine and Department of
Physics and Technology, Donetsk National University
Title: Nonlinear acousto-optical diffraction
Seminar language: English
/58/
Date: Wednesday 2012.01.25
Speaker: Dr Ewa Banachowicz
Affiliation: Molecular Biophysics Division, Physics Faculty, AMU
Title: Protein structure prediction (Przewidywanie struktury
białek)
Seminar language: Polish
/57/
Date: Wednesday 2012.01.18
Speaker: Dr Ireneusz Weymann
Affiliation: Mesoscopic Physics Division, Physics Faculty, AMU
Title: The Kondo effect in quantum dots coupled to ferromagnetic
leads
Seminar language: English
/56/
Date: Wednesday 2012.01.11
Speaker: Dr Jarosław Kłos
Affiliation: Nanomaterials Physics Division, Physics Faculty, AMU
Title: Electronic states in graphene nanoribbons.
Seminar language: English
/55/
Date: Wednesday 2012.01.4
Speaker: Prof. Ryszard Tanaś
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Quantum correlations of two qubits.
Seminar language: English
/54/
Date: Wednesday 2011.12.14
Speaker: Prof. A. A. Kargin
Affiliation: Dean of the Faculty of Physics |
Technology,
Donetsk National University, Ukraine
Title: Overview |
Perspectives of Collaboration with the Faculty
of Physics |
Technology of the Donetsk National University.
Seminar language: English
/53/
Date: Wednesday 2011.12.14
Speaker: Dr hab. Maciej Krawczyk
Affiliation: Nanomaterials Physics Division, Physics Faculty, AMU
Title: Magnonic crystals: Mastering magnons at nanoscale.
Seminar language: English
/52/
Date: Friday 2011.12.09
Speaker: Prof. Paweł Horodecki
Affiliation: Technical University of Gdańsk and National
Center for Quantum Information in Sopot
Title: Quantum correlations.
Seminar language: English
/51/
Date: Wednesday 2011.12.7
Speaker: Prof. Nataliya Dadoenkowa
Affiliation: Donetsk Physical and Technical Institute of the
NAS of Ukraine
Title: One-dimensional photonic crystals with combined
superconducting defect layers.
Seminar language: English
/50/
Date: Wednesday 2011.11.30
Speaker: M.Sc. Yuliya Dadoenkowa
Affiliation: Donetsk Physical and Technical Institute of the
NAS of Ukraine
Title: Peculiarities of the Electric Field Controlling of
Goos-Hänchen Effect and Faraday Effect in 1D Magnetic Photonic
Crystals.
Seminar language: English
/49/
Date: Wednesday 2011.11.09
Speaker: Prof. Igor Lyubchanskii
Affiliation: Donetsk Physical and Technical Institute of the
National Academy of Sciences of Ukraine and Department of
Physics and Technology, Donetsk National University
Title: Magneto-photonic crystals and related structures
Seminar language: English
/48/
Date: Wednesday 2011.04.11
Speaker: Dr Przemysław Chełminiak
Affiliation: Solid State Theory Division, Physics Faculty, AMU
Title: Evolution of scale-free networks on fractal networks
/47/
Date: Tuesday 2011.06.14
Speaker: Dr Marceli Kaczmarski
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Raman spectroscopy and nanotechnology for cancer
diagnostics
/46/
Date: Tuesday 2011.04.24
Speaker: Prof. Ryszard Tanaś
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Nonclassical correlations in the system of two atoms
/45/
Date: Thursday 2011.04.14
Speaker: B.Sc. Joanna Luchowska
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Introduction to quantum chemistry
/44/
Date: Thursday 2011.02.03
Speaker: Dr Wojciech Czart
Affiliation: Zakład Stanów Elektronowych Ciała Stałego, Wydział
Fizyki UAM
Title: Marketing wyszukiwarek internetowych - optymalizacja
/43/
Date: Thursday 2011.01.27
Speaker: Dr hab. Andrzej Grudka
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: On problem of measures of multi-particle correlations
/42/
Date: Thursday 2011.01.13
Speaker: M.Sc. Monika Bartkowiak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Superconducting quantum computation
/41/
Date: Tuesday 2010.12.07
Speaker: M.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Optical simulations of systems strongly scattering light on
example of printer ink
/40/
Date: Thursday 2010.11.25
Speaker: M.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Quantum cloning of qubits
/39/
Date: Thursday 2010.11.18
Speaker: M.Sc. Bohdan Horst
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Introduction to quantum engineering
/38/
Date: Thursday 2010.11.04
Speaker: Prof. Ryszard Tanaś
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Quantum and classical correlations of two atoms
/37/
Date: Thursday 2010.10.21
Speaker: Dr Yoichi Uetake
Affiliation: Faculty of Mathematics and Informatics, AMU
Title: Scattering theory in quantum mechanics
Seminar language: English
/36/
Date: Thursday 2010.10.14
Speaker: Dr hab. Jacek Kubicki
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Shaping pulses in ultra-fast laser spectroscopy
Seminar language: Polish
/35/
Date: Tuesday 2010.05.25
Speaker: Prof. Lianao Wu
Affiliation: IKERBASQUE of the Basque Foundation for Science and
Department of Theoretical Physics and History of Science of the
Basque Country University (EHU/UPV), Bilbao, Spain
Title: Quantum phase transitions and quantum entanglement (part
I)
Seminar language: English
/34/
Date: Thursday 2010.05.20
Speaker: Dr Grzegorz Chimczak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Finding atom-cavity parameters
Seminar language: Polish
/33/
Date: Thursday 2010.03.13
Speaker: M.Sc. Joanna Modławska
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Improving the fraction of entanglement
Seminar language: Polish
/32/
Date: Thursday 2010.05.6
Speaker: M.Sc. Bohdan Horst
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Introduction to Mathematics of Finance
Seminar language: Polish
/31/
Date: Thursday 2010.05.6
Speaker: M.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Research at the Niels Bohr Institute in Copenhagen
Seminar language: Polish
/30/
Date: Thursday 2010.04.29
Speaker: Dr hab. Krzysztof Grygiel
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Anomalous rotational diffusion
Seminar language: Polish
/29/
Date: Thursday 2010.04.22
Speaker: M.Sc. Monika Bartkowiak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Linear-optical implementations of quantum gates - iSWAP and
CNOT
Seminar language: Polish
/28/
Date: Thursday 2010.04.15
Speaker: Dr hab. Krzysztof Grygiel
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: New approach to non-Markovian processes
Seminar language: Polish
/27/
Date: Thursday 2010.04.8
Speaker: Dr Krzysztof Gibasiewicz
Affiliation: Molecular Biophysics Division, Physics Faculty, AMU
Title: Exciton coupling in photosystem I - photosynthetic
protein-dye complex
Seminar language: Polish
/26/
Date: Wednesday 2010.03.31
Speaker: Prof. Tadeusz Bancewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Induced hyper-polarization of complexes H2-He-H2-Ar
Seminar language: Polish
/25/
Date: Thursday 2010.03.25
Speaker: Dr Andrzej Grudka
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Nonadditivity of quantum capacity of quantum multi-access
channels breaking quantum entanglement
Seminar language: Polish
/24/
Date: Thursday 2010.03.18
Speaker: M.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Optimal quantum cloning and quantum teleportation
Seminar language: Polish
/23/
Date: Thursday 2010.03.11
Speaker: Dr Andrzej Koper
Affiliation: Quantum Physics Division, Physics Faculty, AMU
Title: Gutzwiller states, functions τ, and Metropolis
algorithm
Seminar language: Polish
/22/
Date: Thursday 2010.03.04
Speaker: Prof. Ryszard Tanaś
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Sudden death and sudden birth of entanglement
Seminar language: Polish
/21/
Date: Wednesday 2009.06.03
Speaker: Dr Zbigniew Ficek
Affiliation: The National Centre for Mathematics and Physics,
KACST, Riyadh, Saudi Arabia
Title: Squeezed and thresholdless dressed-atom laser in a photonic
crystal
Seminar language: Polish
/20/
Date: Thursday 2009.05.28
Speaker: M.Sc. Monika Bartkowiak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Quantum entanglement and phase transitions
Seminar language: Polish
/19/
Date: Thursday 2009.05.21
Speaker: Dr Marceli Kaczmarski
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Big Bang and Raman spectra of glaserite-type crystals
Seminar language: Polish
/18/
Date: Thursday 2009.05.14
Speaker: Dr Grzegorz Chimczak
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Improving fidelity of quantum teleportation
Seminar language: Polish
/17/
Date: Thursday 2009.05.07
Speaker: B.Sc. Jacek Więcław
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Quantum key distribution protocols
Seminar language: Polish
/16/
Date: Tuesday 2009.04.30
Speaker: B.Sc. Łukasz Olejnik
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Problem of secure acquisition of information
Seminar language: Polish
/15/
Date: Thursday 2008.11.25
Speaker: Dr Anna Kowalewska-Kudłaszyk
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Nonlinear quantum scissors and generation of entangled
states
Seminar language: Polish
/14/
Date: Thursday 2008.11.20
Speaker: Dr Andrzej Grudka
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: On additivity of quantum capacity of quantum channels
Seminar language: Polish
/13/
Date: Thursday 2008.11.13
Speaker: B.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Damping of entangled states and teleportation
Seminar language: Polish
/12/
Date: Tuesday 2008.11.04
Speaker: Dr Marceli Kaczmarski
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Raman spectroscopy in the past and nowadays
Seminar language: Polish
/11/
Date: Friday 2008.09.26
Speaker: B.Sc. Karol Bartkiewicz
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Teleportation through dissipative channels: Conditions for
surpassing the no-cloning limit
Seminar language: English
/10/
Date: Friday 2008.09.26
Speaker: Dr Andrzej Grudka
Authors: Dr Andrzej Grudka and B.Sc. Joanna Modławska
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: How to increase the probability of faithful multiple
teleportation in the KLM scheme
Seminar language: English
/9/
Date: Friday 2008.09.26
Speaker: Prof. Ryszard Tanaś
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Sudden birth and death of entanglement in a two-atom
system
Seminar language: English
/8/
Date: Friday 2008.09.26
Speaker: M.Sc. Mikołaj Czechlewski
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Entanglement distillation of certain mixed states
Seminar language: English
/7/
Date: Friday 2008.09.26
Speaker: B.Sc. Łukasz Olejnik
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Quantum solution to symmetrically private information
retrieval
Seminar language: English
/6/
Date: Friday 2008.09.26
Speaker: Dr Anna Kowalewska-Kudłaszyk
Authors: Dr Anna Kowalewska-Kudłaszyk and dr hab. Wiesław Leoński:
Affiliation: Nonlinear Optics Division, Physics Faculty, AMU
Title: Nonlinear quantum scissors and entanglement
Seminar language: English
/5/
Date: Friday 2008.09.26
Speaker: Dr Paweł Kurzyński
Affiliation: Quantum Electronics Division, Physics Faculty, AMU
Title: Multiple violation of local realism
Seminar language: English
/4/
Date: Friday 2008.09.26
Speaker: Prof. Piotr Tomczak
Affiliation: Affiliation: Quantum Physics Division, Physics
Faculty, AMU
Title: Entanglement in antiferromagnetic spin systems
Seminar language: English
/3/
Date: Friday 2008.09.26
Speaker: Dr Yoichi Uetake
Affiliation: Faculty of Mathematics and Computer Science, Adam
Mickiewicz University
Title: Lax-Phillips scattering and its possible implication in
quantum computing
Seminar language: English
/2/
Date: Friday 2008.09.26
Speaker: Prof. Nobuyuki Imoto
Affiliation: Department of Materials Engineering Science, Graduate
School of Engineering Science, Osaka University, Osaka, Japan
Title: Photonic quantum information processing
Seminar language: English
/1/
Date: Friday 2008.09.26
Speaker: Prof. Hideaki Matsueda
Affiliation: Kochi University and Kyoto University, Japan
Title: Nanostructure realization of quantum computing
Seminar language: English
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