title: Self-propelled particle in an external potential: existence of an effective temperature.
abstract: We study a stationary state of a single self-propelled, athermal particle in linear and quadratic external potentials. The self-propulsion is modeled as a fluctuating internal driving force evolving according to the Ornstein-Uhlenbeck process, independently of the state of the particle. Without an external potential, in the long time limit, the self-propelled particle moving in a viscous medium performs diffusive motion, which allows one to identify an effective temperature. We show that in the presence of a linear external potential the stationary state distribution has an exponential form with the sedimentation length determined by the effective temperature of the free self-propelled particle. In the presence of a quadratic external potential the stationary state distribution has a Gaussian form. However, in general, this distribution is not determined by the effective temperature of the free self-propelled particle.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, Colorado 80525, USA.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Szamel
mesh_terms: D008962:Models, Theoretical; D009038:Motion; D013696:Temperature