Fluctuation relations in simple examples of non-equilibrium steady states

TL;DR

This paper explores fluctuation relations in non-equilibrium steady states described by Langevin dynamics, revealing a modified fluctuation-dissipation theorem that accounts for probability currents and local velocities.

Contribution

It demonstrates how fluctuation relations simplify to a modified fluctuation-dissipation theorem near non-equilibrium steady states with probability currents.

Findings

Fluctuation relations reduce to a modified fluctuation-dissipation theorem near steady states.

The modified relation can be interpreted as equilibrium-like in a moving reference frame.

Probability currents influence the form of fluctuation relations.

Abstract

We discuss fluctuation relations in simple cases of non-equilibrium Langevin dynamics. In particular, we show that close to non-equilibrium steady states with non-vanishing probability currents some of these relations reduce to a modified version of the fluctuation-dissipation theorem. The latter may be interpreted as the equilibrium-like relation in the reference frame moving with the mean local velocity determined by the probability current.