title: Continuum theory of phase separation kinetics for active Brownian particles.
abstract: Active Brownian particles (ABPs), when subject to purely repulsive interactions, are known to undergo activity-induced phase separation broadly resembling an equilibrium (attraction-induced) gas-liquid coexistence. Here we present an accurate continuum theory for the dynamics of phase-separating ABPs, derived by direct coarse graining, capturing leading-order density gradient terms alongside an effective bulk free energy. Such gradient terms do not obey detailed balance; yet we find coarsening dynamics closely resembling that of equilibrium phase separation. Our continuum theory is numerically compared to large-scale direct simulations of ABPs and accurately accounts for domain growth kinetics, domain topologies, and coexistence densities.
authors.affiliation: SUPA, School of Physics and Astronomy, University of Edinburgh, JCMB Kings Buildings, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: Joakim
authors.initials: J
authors.lastname: Stenhammar
authors.forename: Adriano
authors.initials: A
authors.lastname: Tiribocchi
authors.forename: Rosalind J
authors.initials: RJ
authors.lastname: Allen
authors.forename: Davide
authors.initials: D
authors.lastname: Marenduzzo
authors.forename: Michael E
authors.initials: ME
authors.lastname: Cates