Diffusion properties of active particles with directional reversal

TL;DR

This paper investigates how active particles that reverse direction influence their diffusion, deriving a general formula and revealing an optimal noise level that maximizes diffusion, with implications for microbiological systems.

Contribution

It introduces a stochastic clock model for directional reversal and derives a general diffusion coefficient expression for such particles.

Findings

Existence of an optimal rotational noise amplitude for maximum diffusion

Derived a general expression for the diffusion coefficient

Relevance to microbiological systems and potential for experimental validation

Abstract

The diffusion properties of self-propelled particles which move at constant speed and, in addition, reverse their direction of motion repeatedly are investigated. The internal dynamics of particles triggering these reversal processes is modeled by a stochastic clock. The velocity correlation function as well as the mean squared displacement is investigated and, furthermore, a general expression for the diffusion coefficient for self-propelled particles with directional reversal is derived. Our analysis reveals the existence of an optimal, finite rotational noise amplitude which maximizes the diffusion coefficient. We comment on the relevance of these results with regard to microbiological systems and suggest further experiments in this context.