Tuning attraction and repulsion between active particles through persistence

Matthew J Metson, Martin R Evans, Richard A Blythe

Published 2022-07-04Version 1

We consider the interplay between persistent motion, which is a generic property of active particles, and a recoil interaction which causes particles to jump apart on contact. This recoil process is inspired by the `shock' dynamics of certain microorganisms, such as \textit{Pyramimonas octopus}, and always generates an effective repulsion between a pair of passive particles. Highly persistent particles can be attractive or repulsive, according to the shape of the recoil distribution. We show that the latter case admits an unexpected transition to attraction at intermediate persistence lengths that originates in the advective effects of persistence. This allows active particles to control the way they interact by varying the persistence length.