MIPS Beyond Simple Repulsive Interactions: from Attractive Forces to Aligning Torques

Among active matter phenomena, motility-induced phase separation (MIPS), which leads to condensed active matter in the absence of cohesive forces, is a paradigmatic example of how activity overcomes the constraints imposed in equilibrium [1]. MIPS starts to be well understood for self-propelled spherical particles interacting via purely repulsive forces [2,3,4]. Its interplay with other interactions, from attractive tails to aligning torques, leads to a rich physics that we illustrate with numerical simulations [5,6,7]. We then show how a generalized stress tensor formalism accounts for MIPS in the presence of these more general interactions, accounting both for re-entrance phenomena as well as alignment-induced MIPS.

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