Self-Polarizing Microswimmers in Active Density Waves

TL;DR

This paper investigates how self-polarization and angular fluctuations influence the directed movement of artificial microswimmers in active density waves, combining numerical and analytical methods to understand their transport behavior.

Contribution

It introduces a combined analysis of self-polarization and angular fluctuations in microswimmers, revealing their roles in selective transport within inhomogeneous media.

Findings

Self-polarization can enhance or hinder microswimmer navigation.

Angular fluctuations increase exploration and diffusion toward active regions.

The relative strength of mechanisms determines transport efficiency.

Abstract

An artificial microswimmer drifts in response to spatio-temporal modulations of an activating suspension medium. We consider two competing mechanisms capable of influencing its tactic response: angular fluctuations, which help it explore its surroundings and thus diffuse faster toward more active regions, and self-polarization, a mechanism inherent to self-propulsion, which tends to orient the swimmer's velocity parallel or antiparallel to the local activation gradients. We investigate, both numerically and analytically, the combined action of such two mechanisms. By determining their relative magnitude, we characterize the selective transport of artificial microswimmers in inhomogeneous activating media.