Local Thermodynamic Equilibrium at Three Levels

TL;DR

This paper develops a unified framework for local thermodynamic equilibrium across macroscopic, mesoscopic, and microscopic levels, linking classical thermodynamics, hydrodynamical fluctuations, and quantum statistical mechanics.

Contribution

It introduces coordinated formulations of local thermodynamic equilibrium conditions at three different levels, connecting quantum and classical descriptions.

Findings

Quantum statistical mechanics implies a local zeroth law.

Unified conditions expressed in hydrodynamical variables.

Bridges classical, mesoscopic, and microscopic thermodynamics.

Abstract

We present coordinated formulations of local thermodynamical equilibrium conditions at three levels, namely the macroscopic one of classical thermodynamics, the mesoscopic one of hydrodynamical fluctuations and the microscopic one of quantum statistical mechanics. These conditions are all expressed in terms of the hydrodynamical variables of the macroscopic picture, and the quantum statistical ones are shown to imply a local version of the zeroth law.