Jamming and flocking in the restricted active Potts model

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.

Automated summary

We studied the active Potts model with site occupancy restriction or on-site repulsion and found that it exhibits a surprisingly rich variety of self-organized spatial patterns. The introduction of volume exclusion features leads to the occurrence of bands and lanes of moving particles, and with strong volume exclusion, low temperature, high activity, and large particle density, jams due to motility-induced phase separation can be facilitated. Through phase diagrams, we identified phase boundaries and studied the transition between jammed and free-flowing phases, providing qualitative and quantitative predictions on how jamming might be delayed or dissolved. We also formulated and analyzed a hydrodynamic theory for the restricted APM, which predicts various features of the microscopic model.