Current fluctuations in non-equilibrium diffusive systems: an additivity principle

TL;DR

This paper introduces an additivity principle to compute the full distribution of current fluctuations in non-equilibrium diffusive systems, extending previous models and applicable to complex networks, with results consistent with fluctuation symmetry.

Contribution

It proposes a simple additivity principle that enables calculation of current fluctuation distributions from only the first two cumulants, generalizing previous models and applicable to complex networks.

Findings

Distribution satisfies Gallavotti-Cohen symmetry

Generalizes previous results for symmetric simple exclusion process

Applicable to complex diffusive networks including loops

Abstract

We formulate a simple additivity principle allowing to calculate the whole distribution of current fluctuations through a large one dimensional system in contact with two reservoirs at unequal densities from the knowledge of its first two cumulants. This distribution (which in general is non-Gaussian) satisfies the Gallavotti-Cohen symmetry and generalizes the one predicted recently for the symmetric simple exclusion process. The additivity principle can be used to study more complex diffusive networks including loops.