Effect of interparticle interaction on motility induced phase separation of self-propelled inertial disks

TL;DR

This study investigates how disk softness and inertia influence motility induced phase separation (MIPS) in self-propelled disks, revealing that softness suppresses phase separation while inertia promotes it, with implications for soft active matter.

Contribution

It demonstrates the combined effects of softness and inertia on MIPS, extending understanding beyond hard-core disk models to soft active matter systems.

Findings

Soft disks phase separate only when hard

Inertia enables phase separation in softer disks

Phase diagram significantly altered by softness and inertia

Abstract

Phase diagram of the phenomenon of motility induced phase separation (MIPS) for a collection of self-propelled interacting disks is explored using Langevin dynamics simulation with particular emphasis on disk wall softness and the range of interaction amongst disks. We bring out important changes in the MIPS phase diagram both due to softness and inertia of the disks. Specifically, we show that overdamped softer disks phase separate while MIPS becomes possible only for harder disks in the inertial limit. Unlike most of the earlier studies on MIPS which consider hard-core disks, our findings may be directly applicable to soft active matter for a range of biological systems.