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DY: Fachverband Dynamik und Statistische Physik
DY 31: Focus Session: Nonequilibrium Collective Behavior in Open Classical and Quantum Systems
DY 31.6: Hauptvortrag
Donnerstag, 20. März 2025, 10:45–11:15, H37
Strong coupling and coherence in quantum thermodynamics — •Janet Anders1,2, Federico Cerisola2, James Cresser2, and et al2 — 1Universität Potsdam, Germany — 2Exeter University, UK
The interaction of nanoscale and quantum systems with their environment can be relatively strong, and alter the equilibrium state. For open quantum systems, explicit expressions of these so-called mean force (MF) equilibrium states have been missing. In this talk I will report on useful analytic expressions of these states, valid for a general quantum system in contact with a bosonic bath [1]. The results are illustrated with the well-known spin-boson model, for which we provide the first classification of coupling regimes, from weak to ultrastrong, and for both the quantum and classical setting [2].
In the second part of the talk, I will briefly comment on quantum signatures that arise in thermodynamic processes due to the presence of coherences. For example, the work distribution of time-varying quantum systems violates the corresponding classical fluctuation-dissipation relation for slowly driven processes [3]. A geometric framework is proposed to find optimal trade-offs between dissipation and fluctuations. Coherences also give rise to quantum irreversibility. We unravel how this irreversibility manifests itself in energetic exchanges that differ from those in the classical regime [4].
[1] PRL 127, 250601 (2021)
[2] NJP 26, 053032 (2024)
[3] PRL 123, 230603 (2019)
[4] Comm. Phys. 3, 1 (2020)
Keywords: quantum thermodynamics; strong coupling; open quantum systems; quantum coherences