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arXiv · 2602.15392

Dual thermodynamic ensembles, relative entropies, and excess free energy

Gavin E. Crooks
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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.

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Gavin E. Crooks. 2026-02-17. Dual thermodynamic ensembles, relative entropies, and excess free energy. https://arxiv.org/abs/2602.15392

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