Validation of the Jarzynski relation for a system with strong thermal coupling: an isothermal ideal gas model

TL;DR

This study tests the Jarzynski relation in a strongly coupled, isothermal ideal gas system with a moving piston, confirming its validity through numerical and analytical methods despite broken microscopic reversibility.

Contribution

It demonstrates the Jarzynski relation holds in a strongly coupled, isothermal ideal gas system with a moving piston, extending its applicability beyond previously proven cases.

Findings

Jarzynski relation is valid in the studied system.

Numerical confirmation across various parameters.

Analytical proof in the fast piston limit.

Abstract

We revisit the paradigm of an ideal gas under isothermal conditions. A moving piston performs work on an ideal gas in a container that is strongly coupled to a heat reservoir. The thermal coupling is modelled by stochastic scattering at the boundaries. In contrast to recent studies of an adiabatic ideal gas with a piston [R.C. Lua and A.Y. Grosberg, \textit{J. Phys. Chem. B} 109, 6805 (2005); I. Bena et al., \textit{Europhys. Lett.} 71, 879 (2005)], container and piston stay in contact with the heat bath during the work process. Under this condition the heat reservoir as well as the system depend on the work parameter $\lambda$ and microscopic reversibility is broken for a moving piston. Our model is thus not included in the class of systems for which the non-equilibrium work theorem has been derived rigorously either by Hamiltonian [C. Jarzynski, \textit{J. Stat. Mech.} P09005 (2004)] or stochastic methods [G.E. Crooks, \textit{J. Stat. Phys.} 90, 1481 (1998)]. Nevertheless the validity of the non-equilibrium work theorem is confirmed both numerically for a wide range of parameter values and analytically in the limit of a very fast moving piston, i.e. in the far non-equilibrium regime.