A nonequilibrium equality for free energy differences

TL;DR

This paper derives a nonequilibrium equality that relates free energy differences to finite-time work measurements, unifying known equilibrium identities as special cases, and providing a new way to compute free energy changes.

Contribution

It introduces a nonequilibrium equality for free energy differences based on finite-time work measurements, extending classical identities.

Findings

Derives a nonequilibrium equality for free energy differences.

Shows classical equilibrium identities as limiting cases.

Provides a practical method for free energy calculations from finite-time experiments.

Abstract

An expression is derived for the classical free energy difference between two configurations of a system, in terms of an ensemble of finite-time measurements of the work performed in parametrically switching from one configuration to the other. Two well-known equilibrium identities emerge as limiting cases of this result.