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DY: Dynamik und Statistische Physik
DY 51: Non-Linear Stochastic Systems
DY 51.7: Talk
Friday, March 31, 2006, 13:00–13:15, H\"UL 186
Phase transitions and “negative heat capacity” of active Brownian particles — •Hendrik U. Bödeker1, Andreas W. Liehr2, and Hans-Georg Purwins1 — 1Westfälische Wilhelms-Universität Münster, Institut für Angewandte Physik, Corrensstr. 2/4, 48149 Münster — 2Freiburger Materialforschungszentrum, Stefan-Meier-Str. 21, 79104 Freiburg i. Br.
Active Brownian particles as a generalization of classical Newtonian particles exhibit a large variety of dynamical properties that have no classical counterpart. In this talk, we focus on the interaction of many active Brownian particles by investigating the clustering behavior under short-ranged interaction. Numerical simulations show that a number of phenomena like phase transitions from a solid to a liquid phase can be found that qualitatively resemble the behavior of classical many-body systems. In addition, new phenomena like “negative heat capacity”, i.e. the decrease of the mean-squared velocity of the particles with increasing fluctuation strength, can be found. We show that these findings essentially depend on the nature of the interaction and that “negative heat capacity” can be looked upon as a stochastic resonance effect.