Motility-induced phase separation is reentrant

Theoretical analysis

We start from a minimal active fluid theory characterizing MIPS from a kinetics approach^21,22,38. The theory describes the steady state of phase separation with a dense clustering phase which is set as close packed and a dilute phase as homogeneous and isotropic. Particles transport between two phases through condensation and evaporation events with rates k_in and k_out, respectively. Absorption rate k_in is assumed to be proportion to the dilute phase number density ρ_g and the characteristic self-propulsion velocity v₀. For the vaporization, the theory sets that active…