Jarzynski equality for a gas particle driven out of equilibrium

TL;DR

This paper investigates the application of Jarzynski's equality to a classical gas particle driven out of equilibrium by changing its mass, analyzing the work done and its relation to free energy differences.

Contribution

It extends Jarzynski's equality to a particle in a gas system with a non-equilibrium process involving mass change and environmental interactions.

Findings

Work done depends on collisions with other particles

Results generalize to systems driven in one degree of freedom

Validates Jarzynski's equality in this non-equilibrium context

Abstract

One particle in a classical perfect gas is driven out of equilibrium by changing its mass over a short time interval. The work done on the driven particle depends on its collisions with the other particles in the gas. This model thus provides an example of a non-equilibrium process in a system (the driven particle) coupled to an environment (the rest of the gas). We calculate the work done on the driven particle and compare the results to Jarzynski's equality relating a non-equilibrium work process to an equilibrium free-energy difference. The results for this model are generalised to the case of a system that is driven in one degree of freedom while interacting with the environment through other degrees of freedom.