Phase separation of self-propelled ballistic particles

Abstract

Self-propelled particles phase separate into coexisting dense and dilute regions above a critical density. The statistical nature of their stochastic motion lends itself to various theories that predict the onset of phase separation. However, these theories are ill equipped to describe such behavior when noise become negligible. To overcome this limitation, we present a predictive model that relies on two density-dependent timescales: ${\tau }_F$, the mean time particles spend between collisions; and ${\tau }_C$, the mean lifetime of a collision. We show that only when ${\tau }_F<{\tau }_C$ do collisions last long enough to develop a growing cluster and initiate phase separation. Using both analytical calculations and active particle simulations, we measure these timescales and determine the critical density for phase separation in both 2D and 3D.

6 pages, 4 figures

References in corpus (8)

• Motility-Induced Phase Separation
• Statistical Mechanics of Interacting Run-and-Tumble Bacteria
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• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
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• Light Activated Self-Propelled Colloids

Cited by in corpus (10)

• Collective forces in scalar active matter
• Interparticle torques suppress motility-induced phase separation for rodlike particles
• Clogging and Depinning of Ballistic Active Matter Systems in Disordered Media
• Phase separation and nucleation in mixtures of particles with different temperatures
• Emergent vortices and phase separation in systems of chiral active particles with dipolar interactions
• From scalar to polar active matter: Connecting simulations with mean-field theory
• The stability phase diagram of active Brownian particles
• Phase separation of active Brownian particles on curved surfaces
• Jamming of multiple persistent random walkers in arbitrary spatial dimension
• Self-propulsion and self-navigation: Activity is a precursor to jamming