Regensburg 2022 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 35: Quantum Chaos and Coherent Dynamics

DY 35.9: Vortrag

Mittwoch, 7. September 2022, 17:45–18:00, H20

Time-dependent Redfield and Lindblad equations with effective time-dependent temperature — •Nikodem Szpak, Lukas Litzba, Eric Kleinherbers, and Jürgen König — Theoretische Physik, Universität Duisburg-Essen, Lotharstr. 1, 47048 Duisburg

For a quantum system coupled to environment we apply the first Markov approximation and write the Redfield equation at the first order in the system-environment coupling. Then, we evaluate the remaining time-dependent integral and approximate it uniformly for all times, temperatures and energies by one simple analytical function which corresponds to the Fermi-Dirac distribution with time-dependent effective temperature T(t). Thus, we obtain a new Redfield equation with time-dependent effective temperature. A consecutive approximation brings it to the Lindblad equation with time-dependent Lindblad operators whose time-dependence enters solely via T(t). The variation of the effective temperature T(t) reflects the sudden switch-on of the system-environment interaction at the beginning and becomes high at early times to eventually fall to the true environment temperature T. We discuss possible physical effects and their measurability in some simple examples.