title: Active motion assisted by correlated stochastic torques.
abstract: The stochastic dynamics of an active particle undergoing a constant speed and additionally driven by an overall fluctuating torque is investigated. The random torque forces are expressed by a stochastic differential equation for the angular dynamics of the particle determining the orientation of motion. In addition to a constant torque, the particle is supplemented by random torques, which are modeled as an Ornstein-Uhlenbeck process with given correlation time τ(c). These nonvanishing correlations cause a persistence of the particles' trajectories and a change of the effective spatial diffusion coefficient. We discuss the mean square displacement as a function of the correlation time and the noise intensity and detect a nonmonotonic dependence of the effective diffusion coefficient with respect to both correlation time and noise strength. A maximal diffusion behavior is obtained if the correlated angular noise straightens the curved trajectories, interrupted by small pirouettes, whereby the correlated noise amplifies a straightening of the curved trajectories caused by the constant torque.
authors.affiliation: Institute of Physics, Humboldt University at Berlin, Newtonstr 15, D-12489 Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Weber
authors.forename: Paul K
authors.initials: PK
authors.lastname: Radtke
authors.forename: Lutz
authors.initials: L
authors.lastname: Schimansky-Geier
authors.forename: Peter
authors.initials: P
authors.lastname: Hänggi
mesh_terms: D000818:Animals; D001703:Biophysics / Q000379:methods*; D004058:Diffusion; D006801:Humans; D046911:Macromolecular Substances; D015233:Models, Statistical; D009038:Motion; D009068:Movement; D016011:Normal Distribution; D016012:Poisson Distribution; D011108:Polymers / Q000737:chemistry; D013269:Stochastic Processes; D013997:Time Factors; D019415:Torque
chemical_list: D046911:Macromolecular Substances; D011108:Polymers