An Extension of the Fluctuation Theorem

TL;DR

This paper extends the stationary state fluctuation theorem to account for large heat fluctuations in a Brownian particle system, predicting observable deviations from conventional theorems in experimental settings.

Contribution

It derives an extended fluctuation theorem applicable to systems with both mechanical and stochastic components, highlighting differences for large fluctuations.

Findings

The extended theorem reduces to the conventional one for small fluctuations.

For large fluctuations, the probability ratio is significantly larger.

The results are observable in experiments similar to Wang et al.'s study.

Abstract

Heat fluctuations are studied in a dissipative system with both mechanical and stochastic components for a simple model: a Brownian particle dragged through water by a moving potential. An extended stationary state fluctuation theorem is derived. For infinite time, this reduces to the conventional fluctuation theorem only for small fluctuations; for large fluctuations, it gives a much larger ratio of the probabilities of the particle to absorb rather than supply heat. This persists for finite times and should be observable in experiments similar to a recent one of Wang et al.