Dual thermodynamic ensembles, relative entropies, and excess free energy

TL;DR

This paper reveals a new thermodynamic interpretation of reverse relative entropy as the excess free energy of a dual ensemble with interchanged energy and entropy roles, extending the understanding of non-equilibrium thermodynamics.

Contribution

It introduces a novel thermodynamic interpretation of reverse relative entropy as the excess free energy of a dual ensemble with swapped energy and entropy roles.

Findings

Reverse relative entropy has a thermodynamic interpretation.

The excess free energy can be understood through dual ensembles.

Interchanging energy and entropy roles yields new insights into non-equilibrium states.

Abstract

It has long been known that the relative entropy of a non-equilibrium ensemble to the corresponding equilibrium ensemble is the excess free energy. We show that the reverse relative entropy also has a thermodynamic interpretation: it is the excess free energy of a dual ensemble in which the roles of energy and entropy are interchanged.