Ensemble Dependence of the Transient Fluctuation Theorem

TL;DR

This paper extends the Transient and Steady State Fluctuation Theorems to different nonequilibrium ensembles and tests these generalizations through molecular dynamics simulations of shear flow.

Contribution

It introduces a generalization of the Fluctuation Theorem to various nonequilibrium ensembles and validates it with simulations.

Findings

Fluctuation Theorem is ensemble dependent at equilibrium.

Generalized theorems apply to isokinetic ensembles.

Simulation results support the generalized theorems.

Abstract

The Fluctuation Theorem gives an analytical expression for the probability of observing second law violating dynamical fluctuations, in nonequilibrium systems. At equilibrium statistical mechanical fluctuations are known to be ensemble dependent. In this paper we generalise the Transient and Steady State Fluctuation Theorems to various nonequilibrium dynamical ensembles. The Transient and Steady State Fluctuation Theorem for an isokinetic ensemble of isokinetic trajectories is tested using nonequilibrium molecular dynamics simulations of shear flow.