Tracer diffusion in crowded narrow channels. Topical review

TL;DR

This review explores the complex and sometimes counter-intuitive diffusion behaviors of tracer particles in crowded, narrow, quasi-one-dimensional channels, highlighting differences from unbounded systems.

Contribution

It provides a comprehensive survey of tracer diffusion in confined geometries, emphasizing novel behaviors and summarizing existing results for both bounded and unbounded crowded environments.

Findings

Rich and counter-intuitive diffusion behaviors in narrow channels

Differences between confined and unbounded tracer diffusion

Survey of diverse results across various geometries

Abstract

We summarise different results on the diffusion of a tracer particle in lattice gases of hard-core particles with stochastic dynamics, which are confined to narrow channels -- single-files, comb-like structures and quasi-one-dimensional channels with the width equal to several particle diameters. We show that in such geometries a surprisingly rich, sometimes even counter-intuitive, behaviour emerges, which is absent in unbounded systems. We also present a survey of different results obtained for a tracer particle diffusion in unbounded systems, which will permit a reader to have an exhaustively broad picture of the tracer diffusion in crowded environments.