SAMOP 2023 – wissenschaftliches Programm

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QI: Fachverband Quanteninformation

QI 29: Quantum Thermodynamics and Open Quantum Systems II

QI 29.4: Vortrag

Donnerstag, 9. März 2023, 15:15–15:30, B302

Long-time equilibration can determine transient thermality — •Karen Hovhannisyan¹, Somayyeh Nemati¹, Carsten Henkel¹, and Janet Anders^{1, 2} — ¹Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany — ²Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK

When two initially thermal many-body systems start interacting strongly, their transient states quickly become non-Gibbsian, even if the systems eventually equilibrate. To see beyond this apparent lack of structure during the transient regime, we use a refined notion of thermality, which we call g-local. A system is g-locally thermal if the states of all its small subsystems are marginals of global thermal states. We numerically demonstrate for two harmonic lattices that whenever the total system equilibrates in the long run, each lattice remains g-locally thermal at all times, including the transient regime. This is true even when the lattices have long-range interactions within them. We compare our findings with the well-known two-temperature model. While its standard form is not valid beyond weak coupling, we show that at strong coupling it can be partially salvaged by adopting the concept of a g-local temperature.