Motility Induced Phase Separation and Frustration in Active Matter Swarmalators

TL;DR

This paper explores how internal phase interactions in active matter swarmalators lead to diverse phase behaviors, including various forms of motility-induced phase separation and frustration, expanding understanding of active matter dynamics.

Contribution

It introduces a model of active swarmalators with internal phases affecting interactions, revealing new phases and complex behaviors not seen in traditional active matter systems.

Findings

Identification of multiple active phases including gel, arrested clusters, labyrinthine, and superlattice states.

Discovery of frustrated MIPS state under attractive anti-synchronization.

Demonstration of how internal phase interactions influence phase separation and organization.

Abstract

We introduce a system of active matter swarmalators composed of elastically interacting run-and-tumble active disks with an internal phase $\phi_i$. The disks experience an additional attractive or repulsive force with neighboring disks depending upon their relative difference in $\phi_i$. In the absence of the internal phase, the system forms a Motility-Induced Phase Separated (MIPS) state, but when the swarmalator interactions are present, a wide variety of other active phases appear depending upon whether the interaction is attractive or repulsive and whether the particles act to synchronize or anti-synchronize their internal phase values. These include a gas-free gel regime, arrested clusters, a labyrinthine state, a regular MIPS state, a frustrated MIPS state for attractive anti-synchronization, and a superlattice MIPS state for attractive synchronization.