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BP: Fachverband Biologische Physik

BP 6: Statistical Physics of Biological Systems II (joint DY, BP)

BP 6.8: Talk

Monday, March 14, 2011, 16:00–16:15, HÜL 186

Perturbation analysis of a reduced model for collective motion: Effects of the initial condition — •Chiu Fan Lee — Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

In a system of noisy self-propelled particles with interactions that favor directional alignment, collective motion will appear if the density of particles increases beyond a certain threshold. We argue here that such a threshold may depend also on the profiles of the initial perturbation in the particle directions. Specifically, we perform mean-field, linear stability, perturbative and numerical analyses on an approximated form of the Fokker-Planck equation describing the system. We find that if an angular perturbation to an initially homogeneous system is large in magnitude, it will be amplified even if the density of the system is below the threshold density obtained from mean-field approximation.

Reference: C.F. Lee. Fluctuation-induced collective motion: A single-particle density analysis. Physical Review E 81, 031125 (2010).