Reentrant Phase Behavior of Self-Propelled Spheres in 2D with Interparticle Attractions

Descriptive Transcript

This video shows a grid, eight boxes high by 10 boxes wide. Each box corresponds to a separate, independent simulation.

The axes labels indicate the Peclet number (Pe = ratio of propulsion velocity to diffusion) and the attractive well-depth U of the Lennard-Jones interaction (in units of the thermal energy kBT).

For moderate attraction strengths (e.g. U=4 kBT), the phase behavior is reentrant. For low propulsion velocities the system forms or kinetically arrested gel driven by the attractive interactions.

As propulsion velocity is increased, the gel first melts into an isotropic fluid, and then undergoes motility-driven phase separation.