Anomalous transport in disordered exclusion processes with coupled particles

TL;DR

This paper investigates how coupling between particles in a disordered asymmetric exclusion process affects transport properties, revealing phase-dependent current behavior and anomalous diffusion phenomena through analytical and numerical methods.

Contribution

It introduces a coupled particle exclusion model with disorder, analyzing its steady states, current decay, and anomalous diffusion, which are novel insights into disordered transport systems.

Findings

Coupling enhances current when particles form a closed string.

Finite strings of particles reduce the current compared to uncoupled models.

Diffusion of a semi-infinite string exhibits anomalous behavior with bias-dependent phases.

Abstract

We consider one-dimensional asymmetric exclusion processes with a simple attractive interaction, where the distance between consecutive particles is not allowed to exceed a certain limit and investigate the consequences of this coupling on the transport properties in the presence of random-force type disorder by means of a phenomenological random trap picture. In the phase-separated steady state of the model defined on a finite ring, the properties of the density profile are studied and the exponent governing the decay of the current with the system size in the biased phase is derived. In case all consecutive particles are coupled with each other and form a closed string, the current is found to be enhanced compared to the model without coupling, while if groups of consecutive particles form finite strings, the current is reduced. The motion of a semi-infinite string entering an initially empty lattice is also studied. Here, the diffusion of the head of the string is found to be anomalous, and two phases can be distinguished, which are characterised by different functional dependences of the diffusion exponent on the bias. The obtained results are checked by numerical simulation.