Migration of active particle in mixtures of rigid and flexible rings

TL;DR

This paper investigates how active particles diffuse in mixtures of rigid and flexible rings, revealing a non-monotonic relationship with optimal composition for maximum diffusion, supported by numerical simulations and theoretical modeling.

Contribution

It introduces a numerical study of active particle dynamics in mixed rigid and flexible ring media, identifying optimal conditions for enhanced diffusion and establishing a universal activity-ratio relationship.

Findings

Diffusivity varies non-monotonically with ring composition.

An optimal rigid-to-flexible ratio maximizes diffusion.

A universal relation between activity and optimal ratio is proposed.

Abstract

The migration of active particles in slowly moving, crowded, and heterogeneous media is fundamental to various biological processes and technological applications, such as cargo transport. In this study, we numerically investigate the dynamics of a single active particle in a medium composed of mixtures of rigid and flexible rings. We observe a non-monotonic dependence of diffusivity on the relative fraction of rigid to flexible rings, leading to the identification of an optimal composition for enhanced diffusion. This long-time non-monotonic diffusion, likely resulting from the different responses of the active particle to rigid and flexible rings, is coupled with transient short-time trapping. The probability distribution of trapping durations is well described by the extended entropic trap model. We further establish a universal relationship between particle activity and the optimal rigid-to-flexible ring ratio for diffusion, which aligns closely with our numerical results.