Jamming and flocking in the restricted active Potts model

TL;DR

This paper investigates how volume exclusion in the active Potts model influences pattern formation, jamming, and phase transitions, providing insights into motility-induced phase separation and developing a hydrodynamic theory for the system.

Contribution

It introduces volume exclusion into the active Potts model, revealing complex self-organized patterns and phase behavior, and formulates a hydrodynamic theory to predict these phenomena.

Findings

Jamming occurs under strong volume exclusion, low temperature, high activity, and high density.

Phase diagrams delineate boundaries between jammed and free-flowing states.

Hydrodynamic theory successfully predicts key features of the microscopic model.

Abstract

We study the active Potts model with either site occupancy restriction or on-site repulsion to explore jamming and kinetic arrest in a flocking model. The incorporation of such volume exclusion features leads to a surprisingly rich variety of self-organized spatial patterns. While bands and lanes of moving particles commonly occur without or under weak volume exclusion, strong volume exclusion along with low temperature, high activity, and large particle density facilitates jams due to motility-induced phase separation. Through several phase diagrams, we identify the phase boundaries separating the jammed and free-flowing phases and study the transition between these phases which provide us with both qualitative and quantitative predictions of how jamming might be delayed or dissolved. We further formulate and analyze a hydrodynamic theory for the restricted APM which predicts various features of the microscopic model.