Berlin 2008 – scientific programme

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BP: Fachverband Biologische Physik

BP 10: Self Propulsion

BP 10.4: Talk

Tuesday, February 26, 2008, 14:45–15:00, C 243

Diffusion in different models of active Brownian particles of relevance in biological self-propelled motion — •Ernesto M. Nicola and Benjamin Lindner — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany

Self-propelled motion is one of the most fascinating aspects of biological systems. This motion can appear in many different biological contexts either inside cells or on the multi-cellular level. Simple phenomenological models can help to understand the dynamics of self-propelled entities and their statistics (including their transport properties). One class of models successfully studied during the last 15 years are active Brownian particles (ABP). Here we study, both theoretically and numerically, the effective diffusion coefficient of one-dimensional ABP models. We show that, depending on the choice of the friction function, the diffusion coefficient does or does not attain a minimum as a function of noise intensity. We furthermore discuss the case of an additional bias breaking the left-right symmetry of the system. We show that this bias induces a drift and that it generally reduces the diffusion coefficient. For a finite range of values of the bias, the models can exhibit a maximum in the diffusion coefficient vs. noise intensity.