Noise and diffusion of particles obeying asymmetric exclusion processes

TL;DR

This paper investigates the relationship between noise and diffusion in particles following asymmetric exclusion processes, revealing a generalized relation in closed systems and differing behavior in open chains through Monte Carlo simulations.

Contribution

It provides a detailed analysis of noise and diffusion in ASEP systems, establishing a generalized Nyquist-Einstein relation for closed rings and contrasting behavior in open chains.

Findings

Diffusion coefficient relates to current noise in closed rings.

Both diffusion and noise decrease with the square root of barriers in closed systems.

In open chains, diffusion depends on concentration, not noise or number of barriers.

Abstract

The relation between noise and Fick's diffusion coefficient in barrier limited transport associated with hopping or tunneling mechanisms of particles obeying the asymmetric simple exclusion processes (ASEP) is physically assessed by Monte Carlo simulations. For a closed ring consisting of a large number of barriers the diffusion coefficient is related explicitly to the current noise thus revealing the existence of a generalized Nyquist-Einstein relation. Both diffusion and noise are confirmed to decrease as the square root of the number of barriers as a consequence of the correlation induced by ASEP. By contrast, for an open linear chain of barriers the diffusion coefficient is found to be no longer related to current noise. Here diffusion depends on particle concentration but is independent of the number of barriers.