Nonergodic subdiffusion from transient interactions with heterogeneous partners

TL;DR

This paper presents a microscopic model explaining nonergodic subdiffusion in biological systems through transient interactions with diffusive partners, linking disorder to anomalous diffusion behaviors.

Contribution

It introduces a novel model where particle diffusion is affected by transient molecular interactions, capturing nonergodic subdiffusion observed in biological media.

Findings

Model reproduces subdiffusion and nonergodicity similar to heavy-tailed CTRW

Dependence of diffusion properties on partner density analyzed

Provides a testable microscopic mechanism for disorder-induced anomalous diffusion

Abstract

Spatiotemporal disorder has been recently associated to the occurrence of anomalous nonergodic diffusion of molecular components in biological systems, but the underlying microscopic mechanism is still unclear. We introduce a model in which a particle performs continuous Brownian motion with changes of diffusion coefficients induced by transient molecular interactions with diffusive binding partners. In spite of the exponential distribution of waiting times, the model shows subdiffusion and nonergodicity similar to the heavy-tailed continuous time random walk. The dependence of these properties on the density of binding partners is analyzed and discussed. Our work provide an experimentally-testable microscopic model to investigate the nature of nonergodicity in disordered media.