Adaiabtic theorems and reversible isothermal processes

TL;DR

This paper investigates quantum isothermal processes, defining key thermodynamic quantities and establishing a theorem that characterizes reversible processes as quasi-static, with implications for entropy, free energy, and the zeroth law.

Contribution

It introduces a quantum statistical mechanics framework for isothermal processes and proves an isothermal theorem linking reversibility to quasi-static evolution.

Findings

Reversible isothermal processes are characterized as quasi-static.

Corollaries relate entropy and free energy changes to reversibility.

Insights into the 0th law of thermodynamics in quantum systems.

Abstract

Isothermal processes of a finitely extended, driven quantum system in contact with an infinite heat bath are studied from the point of view of quantum statistical mechanics. Notions like heat flux, work and entropy are defined for trajectories of states close to, but distinct from states of joint thermal equilibrium. A theorem characterizing reversible isothermal processes as quasi-static processes (''isothermal theorem'') is described. Corollaries concerning the changes of entropy and free energy in reversible isothermal processes and on the 0th law of thermodynamics are outlined.