Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Statistical Physics and Nonlinear Dynamics & Stochastic Processes

Active Brownian particles - from individual to collective dynamics

by Pawel Romanczuk
  • What TSP Termin
  • When May 27, 2011 from 04:00 to 04:00
  • Where Richard-Willstätter-Haus, Faradayweg 10, 14195 Berlin (Dahlem), U-Bahnhof Thielplatz (U3)
  • Attendees Pawel Romanczuk
  • iCal

Abstract:<br><br>We consider first non-interacting self-propelled Brownian particles under the influence of active<br>fluctuations. In contrast to passive fluctuations, associated with a stochastic environment (e.g.<br>ordinary Brownian motion), active fluctuations are assumed to be a pure far from equilibrium<br>phenomenon associated with the activity of the self-propelled particle. Here we consider active<br>fluctuations, as independent stochastic processes in the direction of motion and velocity. We<br>discuss the impact of active fluctuations in generic models of self- propelled particles in one<br>and two spatial dimensions, discuss their stationary velocity and speed distributions as well as<br>diffusion coefficients. We show that, for example, in two dimensions active fluctuations lead to an<br>increased probability of low speeds and, as a consequence, to sharply peaked Cartesian velocity<br>probability densities at the origin. Furthermore, we consider interacting (active) Brownian agents.<br>Hereby we focus on the onset of collective motion due to escape and pursuit interactions, which<br>are motivated by the recently suggested connection between collective motion and cannibalism in<br>certain insects species. We show emergence of large scale collective motion for both interaction<br>types and discuss their different impact on global dynamics. Finally, we discuss some applications<br>of the escape+pursuit framework to modeling collective motion of desert locusts.