Upcoming events

January 21, 2020 at 11:00
 
Seminar given by Robert Alicki [in Polish]
International Centre for Theory of Quantum Technologies, UG
Title: Na początku była praca
The lecture is organized as a part of a Biophysical seminar by the Gdańsk Branch of the Polish Biophysical Society.
 
Abstract:
Przedstawione będą argumenty sugerujące, że początek ewolucji biologicznej wymagał powstania prymitywnych silników chemicznych wytwarzających pracę w postaci mechanicznych oscylacji. Zasada działania takich silników byłaby podobna do funkcjonowania akumulatorów, baterii, a także ogniw paliwowych, fotowoltaicznych i termoelektrycznych. Zgodnie z rozwijaną przez autora i współpracowników teorią, wszystkie te urządzenia wykorzystują sprzężenie zwrotne prowadzące do autooscylacji elektrycznie naładowanej warstwy podwójnej.
 
Place: Faculty of Mathematics, Physics and Computer Science, Wita Stwosza 57, Gdansk, the hall of the Faculty Council (roo no. 21).
 
 
January 15, 2020 at 11:15
 
Seminar given by Horacio M. Pastawski
Universidad Nacional de Córdoba, Argentina
Title: Emergent Behavior in Quantum Dynamics of many-body systems: Quantum Dynamical Phase Transitions and Intrinsic Irreversibility observed through NMR Loschmidt Echoes and OTOCs
 
Abstract:
In recent years, Solid State Nuclear Magnetic Resonance (NMR) has given us the chance to observe surprising dynamical emergent phenomena [1]. This is possible because this technique addresses spins in the thermodynamic limit. We have addressed two phenomena: A) the polarization a spin dimmer, may have a Rabi oscillation that becomes an overdamped polarization transfer when the interaction with a spin environment becomes enough strong as compared with the Rabi frequency [2]. B) A dipolar scaled dynamics [2], which is seen as an apparent spin-diffusion through the study of Out of Time Order Correlations (OTOCs) associated with collective polarization. However, when the Hamiltonian strength is weak respect to uncontrollable residual interactions, Loschmidt Echo experiments reveals that dynamical transition from a reversible dynamics to an irreversible one whose time constant is fixed by the Hamiltonian itself, not by the residual interactions. This intrinsic irreversibility, shows that one should be careful in applying the Schrödinger Equation to many-body systems in the thermodynamic limit.

[1]- Attenuation of polarization echoes in NMR: A test for the emergence of Dynamical Irreversibility in Many-Body Quantum Systems. PR Levstein, G Usaj, HM Pastawski, J. Chem. Phys. 108, 2718-2724 (1998)
[2]- Environmentally induced quantum dynamical phase transition in the spin swapping operation, GA Álvarez, EP Danieli, PR Levstein, and HM Pastawski. J. Chem. Phys. 124, 1 (2006)
[3]-Emergent perturbation independent decay of the Loschmidt echo in a many-body system, CM Sánchez, AK Chattah, KX Wei, L Buljubasich, P Cappellaro, and HM Pastawski, Phys. Rev. Lett. (2020-in press)/ arXiv 1902.06628
[4]-Loschmidt echo in many-spin systems: a quest for intrinsic decoherence and emergent irreversibility, PR Zangara and HM Pastawski, Phys. Scr. 92 033001(2017)
 
Place: International Centre for Theory of Quantum Technologies, Wita Stwosza 63, Gdansk (Chemistry Department), second floor, seminar room no. F305.
 
 

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