MIPS — Motility-Induced Phase Separation

Active Matter Parameters

N particles 300 Self-propulsion v₀ 2.0 Tumble rate λ 0.1 Repulsion ε 2.0 Particle radius r 4 Noise D_r 0.1

Phase Diagnostics

Packing fraction φ—

Cluster fraction—

Max cluster size—

Péclet Pe = v₀/Dᵣr—

Phase—

GasMIPSDense

About

MIPS (Cates & Tailleur 2015): self-propelled particles slow down in dense regions, causing positive feedback — slow particles accumulate more. This leads to phase separation into dense clusters and dilute gas, even without attractive forces. Key parameter: Péclet number Pe = v₀/(Dᵣσ). Phase separation emerges above a critical Pe and packing fraction.