Hannover 2013 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 12: Quantum gases: Bosons I
Q 12.3: Vortrag
Montag, 18. März 2013, 14:45–15:00, E 001
The quantum degenerate regime of driven ideal quantum gases in contact with a thermal bath — •Daniel Vorberg1,2, Roland Ketzmerick1,2, and André Eckardt1 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01387 Dresden — 2Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden
Time-periodically driven quantum systems (Floquet systems) that are weakly coupled to a thermal bath possess a time-periodic non-equilibrium steady state. This state is described by a density operator that is diagonal in the basis of Floquet states, that depends on the details of the coupling to the bath, and that generically violates detailed balance. We study ideal Floquet gases consisting of many non-interacting indistinguishable particles and investigate the influence of the bosonic or fermionic quantum statistic. To this end we consider generic one-dimensional model systems with regular and chaotic Floquet states and study their steady state using quantum-jump Monte Carlo simulations. We find that the density operator is generally not of Gaussian form, implying non-trivial occupation number correlations that deviate from Wick's decomposition. However, these deviations are found to be small and a mean-field theory based on a Gaussian ansatz still provides a good approximation to the exact steady state. We find quantum degenerate regimes where the respective quantum statistics leads to Bose condensation or the emergence of a Fermi edge.