Attraction-Induced Cluster Fragmentation and Local Alignment in Active Particle Systems

TL;DR

This study numerically investigates active Brownian particles with attractive forces, revealing that attraction can fragment clusters and induce local alignment, leading to complex multi-cluster dynamics and spontaneous orientation within clusters.

Contribution

It uncovers the counterintuitive role of attractive interactions in active particle systems, showing they promote multi-cluster states and local alignment without explicit alignment rules.

Findings

Attractive forces disrupt single cluster formation.

Multi-cluster states follow a power-law size distribution.

Clusters exhibit spontaneous local alignment and enhanced motility.

Abstract

We numerically studied active Brownian particles with attractive interactions. Contrary to our intuition, the attractive force between particles disrupts the formation of a single cluster observed in motility-induced phase separation, giving rise to a multi-cluster state characterized by a power-law distribution of cluster sizes. Remarkably, the self-propulsion directions spontaneously align within each cluster, resulting in enhanced cluster motility despite the absence of alignment interactions. This study revealed the intricate role of attractive interactions in the aggregation of motile systems.