Critical motility-induced phase separation belongs to the Ising universality class

Abstract

A collection of self-propelled particles with volume exclusion interactions can exhibit the phenomenology of gas-liquid phase separation, known as motility-induced phase separation (MIPS). The non-equilibrium nature of the system is fundamental to the phase transition, however, it is unclear whether MIPS at criticality contributes a novel universality class to non-equilibrium physics. We demonstrate here that this is not the case by showing that a generic critical MIPS belongs to the Ising universality class with conservative dynamics.

4 pages of Main Text and 11 pages of Supplemental Material. Version 2: New simulation results on the coarsening dynamics and further analytical results on the field-theoretic model added