Active gating: rocking diffusion channels

TL;DR

This paper explores how random boundary rate switching, termed active gating, affects nonequilibrium dynamics in exclusion models, revealing increased entropy production, clustering, and phase transitions driven by the rocking rate.

Contribution

It introduces the concept of active gating in exclusion models and analyzes its effects on density profiles, current, and phase transitions, a novel approach in nonequilibrium statistical mechanics.

Findings

Entropy production increases with rocking rate.

Clustering occurs at the edges in ASEP under active gating.

Bulk transition to maximal current phase in TASEP with high rocking rate.

Abstract

When the contacts of an open system flip between different reservoirs, the resulting nonequilibrium shows increased dynamical activity. We investigate such active gating for one-dimensional symmetric (SEP) and asymmetric (ASEP) exclusion models where the left/right boundary rates for entrance and exit of particles are exchanged at random times. Such rocking makes SEP spatially symmetric and on average there is no boundary driving; yet the entropy production increases in the rocking rate. For ASEP a non-monotone density profile can be obtained with particles clustering at the edges. In the totally asymmetric case, there is a bulk transition to a maximal current phase as the rocking exceeds a finite threshold, depending on the boundary rates. We study the resulting density profiles and current as functions of the rocking rate.