Collective ballistic motion explains fast aggregation in adhesive active matter

TL;DR

This paper demonstrates that adhesive active particles exhibit ballistic aggregation via flocking, providing a unified framework to explain diverse cellular aggregation behaviors and insights into tissue organization.

Contribution

It introduces a new kinetic regime of ballistic aggregation driven by flocking in adhesive active matter, supported by analytical and numerical analysis.

Findings

Ballistic aggregation occurs when cluster persistence exceeds intercluster distance growth.

Distinct non-collective kinetic regimes, including long-lived transients, are identified.

The framework explains experimental aggregation exponents in cellular systems.

Abstract

Inspired by motile cells in tissue formation, we find that active systems of self-aligning adhesive particles undergo ballistic aggregation through a flocking transition. This kinetic regime emerges when the cluster persistence length grows faster with cluster mass than the intercluster distance does. We also identify and explain distinct non-collective kinetic regimes, including biologically relevant long-lived transients. Our analytical and numerical results offer a unified framework explaining the broad range of experimentally observed aggregation exponents in cellular systems and reveal physical principles potentially critical for timely tissue organization.