Current reversals in driven lattice gases and Brownian motion

TL;DR

This paper derives conditions under which current reversals occur in driven lattice gases and Brownian particles, revealing how time-dependent drivings and particle interactions influence flow directions in nonequilibrium systems.

Contribution

It provides a theoretical framework based on particle-hole symmetry to predict current reversals in driven lattice gases and extends insights to continuous-space Brownian motion.

Findings

Current reversals occur if the driving potential changes sign after a translation in time or space.

The framework applies to nonstationary dynamics and time-dependent steady states.

Demonstrated current reversals in Brownian particles driven by traveling waves.

Abstract

Particle currents flowing against an external driving are a fascinating phenomenon in both single-particle and interacting many-particle systems. Underlying physical mechanisms of such current reversals are not fully understood yet. Predicting their appearance is difficult, in particular for interaction-induced ones that emerge upon changes of the particle density. We here derive conditions on external time-dependent drivings, under which current reversals occur in lattice gases with arbitrary pair interactions. Our derivation is based on particle-hole symmetry and shows that current reversals must emerge if the time-varying driving potential changes sign after a translation in time and/or space. Our treatment includes nonstationary dynamics and time-dependent spatially averaged currents in nonequilibrium steady states. It gives insight also into possible occurrences of current reversals in continuous-space dynamics, which we demonstrate for hardcore interacting particles driven across a periodic potential by a traveling wave.