Thermodynamics and order beyond equilibrium - the physics of periodically driven quantum systems (Prof. R. Moessner)
- Datum: 15.11.2016
- Uhrzeit: 14:30 - 15:30
- Vortragende(r): Prof. Dr. Roderich Moessner, Direktor am MPI für Physik Komplexer Systeme, Dresden
- Raum: Herbert Walther Lecture Hall
- Gastgeber: MPQ
Extending these ideas and concepts to the non-equilibrium setting is a challenging topic, in itself of perennial interest. Here, we study perhaps the simplest non-equilibrium class of quantum problems, namely Floquet systems, i.e. systems whose Hamiltonians depend on time periodically, SH(t + T) = H(t)S. For these, there is no energy conservation, and hence not even a natural concept of temperature.
We find that it is nonetheless possible to identify several fundamentally distinct thermodynamic ensembles. We also ask if there exists a sharp notion of a phase in such driven, interacting quantum systems. Disorder turns out to play a crucial role, enabling the existence of states which are straightforward analogues of equilibrium states with broken symmetries and topological order, while others--genuinely new to the Floquet problem--are characterized by a combination of order and non-trivial periodic dynamics.
This work was done in collaboration with Arnab Das, Vedika Khemani, Achilleas Lazarides and Shivaji Sondhi.
Phys. Rev. Lett. 112, 150401 (2014);
Phys. Rev. E 90 , 012110 (2014);
Phys. Rev. Lett. 115, 030402 (2015);
Phys. Rev. Lett. 116, 250401 (2016)