Dresden 2020 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 52: Quantum Dynamics, Decoherence and Quantum Information
DY 52.3: Talk
Thursday, March 19, 2020, 15:30–15:45, HÜL 186
Improving non-perturbative approximations of open-system dynamics using fermionic duality — •Valentin Bruch1, Konstantin Nestmann1, Maarten Wegewijs1,2,3, Jens Schulenborg4, and Janine Splettstoesser5 — 1Institute for Theory of Statistical Physics, RWTH Aachen, 52056 Aachen, Germany — 2JARA-FIT, 52056 Aachen, Germany — 3Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany — 4Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen — 5Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-41298 Göteborg
The evolution of a large class of fermionic open quantum systems with strong memory effects obeys an exact relation known as “fermionic duality”. Given any description of the evolution of states (Schrödinger picture), it explicitly provides the corresponding description of the evolution of observables (Heisenberg picture) by a parameter substitution and some simple operations. We apply this to a non-perturbative semigroup approximation that is both completely positive and trace-preserving, as well as to its correction by a so-called “initial slip”, and present a detailed comparison of these two approximations. We show that, surprisingly, the initial slip correction can be constructed for a large part using only the duality relation, circumventing further model-specific calculations. The main features of both approximations can already be seen in the exactly solvable resonant level model with strong coupling to a fermionic reservoir at finite temperature.