Berlin 2012 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 25: Brownian Motion and Transport
DY 25.6: Talk
Thursday, March 29, 2012, 11:00–11:15, MA 004
Active Brownian Particles with Active Fluctuations — •Pawel Romanczuk1, Robert Grossmann2, and Lutz Schimansky-Geier2 — 1Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden — 2Institut für Physik, Humboldt Universität zu Berlin, 12489 Berlin
We study the effect of different types of noise on the dynamics of self-propelled agents with variable speed (active Brownian particles). We distinguish between passive and active fluctuations. Passive fluctuations are considered independent of the direction of particle’s motion (e.g., thermal fluctuations). In contrast, active ones are assumed to be intrinsically connected with the propulsion mechanism of the agent and, as a result, correlated with its time-dependent orientation. We calculate the stationary speed and velocity probability density functions of non-interacting active Brownian particles in the presence of both fluctuation types and discuss the generic signature of active fluctuations [1]. Furthermore, we discuss swarming of active Brownian particles interacting via a velocity-alignment force [2]. We show, based on the results of a corresponding mean-field theory, how the type of fluctuations has a strong impact on the onset and stability of collective motion.
[1] P. Romanczuk and L. Schimansky-Geier, Phys Rev Lett, 106, 230601 (2011)
[2] P. Romanczuk and L. Schimansky-Geier, Ecol Compl, in press, doi:10.1016/j.ecocom.2011.07.008 (2011)