Regensburg 2013 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 41: Colloids and Complex Liquids I
CPP 41.5: Talk
Thursday, March 14, 2013, 11:00–11:15, H40
Two-dimensional active Brownian motion of asymmetric microswimmers — •Borge ten Hagen1, Felix Kümmel2, Raphael Wittkowski1, Ivo Buttinoni2, Giovanni Volpe3, Clemens Bechinger2,4, and Hartmut Löwen1 — 1Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf — 22. Physikalisches Institut, Universität Stuttgart — 3Department of Physics, Bilkent University, Cankaya, Ankara, Turkey — 4Max-Planck-Institut für Intelligente Systeme, Stuttgart
We study the Brownian dynamics of asymmetric self-propelled particles in two dimensions. In our theoretical model based on the Langevin equations the propulsion mechanism is taken into account by means of an effective internal force. For asymmetric particles a non-central drive and translation-rotation coupling lead additionally to an effective intrinsic torque. When external forces are neglected, such particles move on a circular trajectory and the noise-averaged trajectory is predicted to be a logarithmic spiral. Under gravity several qualitatively different types of motion are found: Either a straight downward or upward motion (gravitaxis) occurs or the particle describes a periodic circling motion. Our theoretical description, which is very general and holds for arbitrarily shaped microswimmers, is verified in experiments with L-shaped model swimmers.