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Q: Fachverband Quantenoptik und Photonik
Q 15: Quantum gases (Bosons) II
Q 15.4: Vortrag
Dienstag, 10. März 2020, 12:00–12:15, e214
(Non)thermal states of ideal Bose gases contact with external reservoirs: The effect of finite reservoir coupling — •Alexander Schnell1 and Juzar Thingna2 — 1Max-Planck-Institut für Physik komplexer Systeme, Dresden, Germany — 2IBS Center for Theoretical Physics of Complex Systems, Daejeon, South Korea
The standard framework in which systems in weak contact to external heat-reservoirs are investigated leads to a Lindblad master equation. The underlying assumptions are that the system–reservoir coupling is infinitely weak such that Born-, Markov- and rotating-wave approximation can be performed. For any finite system–reservoir coupling, however, the rotating-wave approximation cannot be performed. Using the standard Born- and Markov approximation one finds a different equation of motion, the Redfield quantum master equation. Contrary to common belief, it was shown that the steady state of this Redfield equation is incorrect already in the first order that goes beyond the Lindblad master equation. Still, there exists a procedure to extract the correct first order correction only from the Lindblad steady state and the Redfield rates [J. Chem. Phys. 136(19),194110 (2012)]. In general, an application of this procedure to quantum many-body systems is out of reach, since it requires knowledge of the full many-body eigenenergies and -states. An exception to this rule are ideal quantum gases. We apply this procedure to the noninteracting Bose gases, both for thermal states and nonequilibrium steady states, and discuss the impact of different bath models.