Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 25: Focus: Active Fluids
CPP 25.3: Vortrag
Mittwoch, 24. März 2010, 10:30–10:45, H39
Brownian dynamics of a self-propelled particle on a substrate — •Borge ten Hagen1, Sven van Teeffelen2, and Hartmut Löwen1 — 1Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany — 2Department of Molecular Biology, Princeton University, LTL-343A Washington Road, Princeton, NJ 08544, USA
By solving the Langevin equation analytically, we study the overdamped Brownian motion of a self-propelled particle which is driven by a projected internal force. The ``active'' particle under study is restricted to move along a linear channel or in a two-dimensional plane. Its orientation, the direction of the internal force, is either freely diffusing on the unit sphere or confined to a plane perpendicular to the substrate. For a subset of the cases considered, the impact of a uniaxial torque and of external potentials is investigated as well. While the basic model applies to spherical particles, a generalized version which holds for ellipsoidal particles is also developed. The model is relevant for active particles like catalytically driven Janus particles and bacteria moving on a substrate. Analytical results for the first four time-dependent displacement moments are presented and analysed for several special situations. A significant dynamical non-Gaussian behaviour at finite times is signalled by a non-vanishing normalized kurtosis.