MIPS: active particles slow in dense regions, driving phase separation and glass formation
Phase: liquid | ⟨MSD⟩ = 0.00
Motility-induced phase separation (MIPS): self-propelled particles spontaneously separate into dense/dilute phases
because particles slow on collision, creating a positive feedback loop. At high Péclet number Pe = v₀/(D_rot r),
dense clusters form. At very high packing fraction, the dense phase arrests into an active glass.
The MSD panel shows diffusive (slope 1, liquid) vs sub-diffusive (glass) behavior.