Phase separation in active matter: going beyond the liquid-vapor paradigm – PSAM

Phase separation into coexisting dense and dilute phases is a fundamental self-organization phenomenon in active systems. In recent years, types of phase separation that are impossible at equilibrium -- such as bubbly phase separation or active foams -- were either predicted theoretically or observed experimentally. Not only are we unable to control the type of phase separation that arises in a particular active system, we do not even theoretically know either the morphologies that might arise or their properties. Further, experiments on self-propelled colloids routinely find local hexatic or even crystalline order in the dense phase; here, topological defects are observed to cluster into self-organised structures, but nothing is known about their impact on the macroscopic properties of the phase-separated system. This theoretical project aims to control bubbly phase separation, active foams and defect-riddled hexatic phases in active phase separation, and to describe their macroscopic properties.