Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 27: Nonequilibrium Processes and Self-Organisation
BP 27.7: Vortrag
Freitag, 30. März 2007, 12:15–12:30, H43
Mean-field transition in two dimensional self-propelled particle systems with different alignment mechanisms — •Fernando Peruani1,2, Andreas Deutsch1, and Markus Baer3 — 1Technische Universitaet Dresden, Dresden, Germany — 2Max Planck for the Physics of Complex Systems, Dresden, Germany — 3Physikalisch-Technische Bundesanstalt, Berlin, Germany
We study the emergence of collective effects in two-dimensional systems of self-propelled particles interacting locally through a liquid crystal-based alignment mechanism. In the model particles are driven with a constant absolute velocity and align their direction of motion to the local director. We show through extensive simulations that there is a continuous kinetic phase transition for sufficient low directional noise and high enough density. Moreover, we propose an effective mean-field equation and show that this approach correctly describes the the scaling of the order parameter vs. noise intensity. Similar arguments follow for the ferromagnetic alignment. These findings strongly suggest that self-propelled particles exhibit kinetic mean-field-type transitions in which the critical noise depends explicitly on the density and the alignment mechanism.