Interfacial Polar-Nematic Ordering in Motility-Induced Phase Separation

Motility-induced phase separation (MIPS) is a purely non-equilibrium phenomenon in which self-propelled particles aggregate without any attractive interactions. One surprising feature of MIPS is the emergence of polar-nematic order at the interfacial region, whose underlying physics remains poorly understood. Here, I will use a density-dependence speed model to obtain the corresponding exact polar-nematic ordering structure at the MIPS interfacial region.