<i>Colloquium</i>: Statistical mechanics and thermodynamics at strong coupling: Quantum and classical

TLDR

Classical and quantum systems’ approach to thermal equilibrium, including decoherence and thermalization, remains a longstanding and fundamental problem in statistical mechanics. The colloquium aims to explain how a thermal bath influences a system’s equilibrium state. It reviews both classical and quantum mechanisms, highlighting quantum peculiarities and the difficulties of defining heat in fluctuating thermodynamic potentials.

Abstract

The question of how classical systems approach thermal equilibrium is as old as the foundations of thermodynamics and statistical mechanics. How quantum systems decohere and thermalize is even more puzzling. This Colloquium provides an account of how the thermal equilibrium of a system is influenced by the presence of a thermal bath. It also gives a view of both classical and quantum aspects providing an understanding on the particularities of the quantum case. Moreover, a description of the challenges in the definition of heat from the perspective of fluctuating thermodynamical potentials is given. An old subject, perhaps, but definitely fundamental.