Steady state statistics of driven diffusions

TL;DR

This paper investigates the steady-state fluctuation properties of driven overdamped diffusions, introducing new concepts like traffic and analyzing the coupling between occupation and current fluctuations out of equilibrium.

Contribution

It provides a thermodynamic interpretation of joint occupation and current fluctuations, highlighting the canonical structure and introducing traffic as a complement to entropy production.

Findings

Joint fluctuations incorporate time-symmetric and antisymmetric sectors

Traffic is a new concept complementing entropy production

Decoupling near equilibrium explains entropy production principles

Abstract

We consider overdamped diffusion processes driven out of thermal equilibrium and we analyze their dynamical steady fluctuations. We discuss the thermodynamic interpretation of the joint fluctuations of occupation times and currents; they incorporate respectively the time-symmetric and the time-antisymmetric sector of the fluctuations. We highlight the canonical structure of the joint fluctuations. The novel concept of traffic complements the entropy production for the study of the occupation statistics. We explain how the occupation and current fluctuations get mutually coupled out of equilibrium. Their decoupling close-to-equilibrium explains the validity of entropy production principles.