title: Pressure and phase equilibria in interacting active brownian spheres.
abstract: We derive a microscopic expression for the mechanical pressure P in a system of spherical active Brownian particles at density ρ. Our exact result relates P, defined as the force per unit area on a bounding wall, to bulk correlation functions evaluated far away from the wall. It shows that (i) P(ρ) is a state function, independent of the particle-wall interaction; (ii) interactions contribute two terms to P, one encoding the slow-down that drives motility-induced phase separation, and the other a direct contribution well known for passive systems; and (iii) P is equal in coexisting phases. We discuss the consequences of these results for the motility-induced phase separation of active Brownian particles and show that the densities at coexistence do not satisfy a Maxwell construction on P.
authors.affiliation: Laboratoire, Matière et Systèmes Complexes, UMR 7057 CNRS/P7, Université Paris Diderot, 75205 Paris Cedex 13, France.
authors.forename: Alexandre P
authors.initials: AP
authors.lastname: Solon
authors.affiliation: SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
authors.forename: Joakim
authors.initials: J
authors.lastname: Stenhammar
authors.affiliation: SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
authors.forename: Raphael
authors.initials: R
authors.lastname: Wittkowski
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Mehran
authors.initials: M
authors.lastname: Kardar
authors.affiliation: Department of Physics, Technion, Haifa 32000, Israel.
authors.forename: Yariv
authors.initials: Y
authors.lastname: Kafri
authors.affiliation: SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Cates
authors.affiliation: Laboratoire, Matière et Systèmes Complexes, UMR 7057 CNRS/P7, Université Paris Diderot, 75205 Paris Cedex 13, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Tailleur