Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 4: Brownian motion and transport

DY 4.2: Talk

Monday, February 25, 2008, 14:30–14:45, MA 004

Active Brownian particles and Nosé-Hoover thermostats — •Rainer Klages — School of Mathematical Sciences, Queen Mary, University of London, UK

Active Brownian particles refer to a theory that is used in order to model the self-propelled motion of biological entities such as, for example, cells migrating on substrates. For this purpose the friction coefficient of ordinary Langevin dynamics is assumed to be velocity dependent, representing the take-up of energy from some external reservoir and its conversion into kinetic energy. Other well-known generalizations of Langevin equations are deterministic thermal reservoirs for which the Nosé-Hoover thermostat is a simple example. I will show that these two seemingly different concepts are quite related to each other. Particularly, I will focus onto the origin of crater-like velocity distributions, which are produced by both types of generalized Langevin dynamics. Starting from Nosé-Hoover thermostats, I will argue that the crater-like shapes can be understood in terms of a combination of canonical with microcanonical distributions.

Ref.: R.Klages, Microscopic chaos, fractals and transport in nonequilibrium statistical mechanics (World Scientific, Singapore, 2007), Chapter 16.