Pairwise comparison

Quantum mechanics

Separation (statistics)

Phase (matter)

Philosophy

Chemical physics

Ecology

Biology

Statistics

Brownian motion

Computer science

Simple (philosophy)

Classical mechanics

Statistical physics

Geology

Oceanography

Physics

Mathematics

Epistemology

Phase diagram

Artificial intelligence

Particle (ecology)

Brownian dynamics

Phase boundary

Machine learning

Physical Review Letters

Simulation studies of the phase diagram of repulsive active Brownian particles in three dimensions reveal that the region of motility-induced phase separation between a high and low density phase is enclosed by a region of gas-crystal phase separation. Near-critical loci and structural crossovers can additionally be identified in analogy with simple fluids. Motivated by the striking similarity to the behavior of equilibrium fluids with short-ranged pairwise attractions, we show that a direct mapping to pair potentials in the dilute limit implies interactions that are insufficiently attractive to engender phase separation. Instead, this is driven by the emergence of multibody effects associated with particle caging that occurs at sufficiently high number density. We quantify these effects via information-theoretical measures of $n$-body effective interactions extracted from the configurational structure.

Phase Separation and Multibody Effects in Three-Dimensional Active Brownian Particles