Thermodynamic state variables from a minimal set of quantum constituents

TL;DR

This paper derives thermodynamic variables like pressure, entropy, and temperature from the quantum spectral properties of particles, providing a microscopic foundation for thermodynamics and illustrating the eigenstate thermalization hypothesis.

Contribution

It introduces a method to define thermodynamic variables directly from quantum spectral data, linking microscopic quantum chaos to macroscopic thermodynamics.

Findings

Thermodynamic variables can be derived from quantum spectral structure.

Provides a microscopic basis for work and heat definitions.

Illustrates the eigenstate thermalization hypothesis in a new context.

Abstract

We show how the macroscopic state variables pressure, entropy and temperature of equilibrium thermodynamics can be consistently derived from the (quantum) chaotic spectral structure of one or two particles in two-dimensional domains. This provides a definition of work and heat from first principles, a microscopic underpinning of the first and second law of thermodynamics, and a transparent illustration of the ``eigenstate thermalization hypothesis''.