Berlin 2018 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 67: Poster: Active Matter, Microswimmers
DY 67.15: Poster
Donnerstag, 15. März 2018, 15:30–18:00, Poster A
Collective motion of self-propelled rods with velocity-reversal — •Robert Großmann1, Fernando Peruani1, and Markus Bär2 — 1Université Côte d'Azur, Nice, France — 2Physikalisch-Technische Bundesanstalt, Berlin, Germany
We review progress in the theory of self-propelled rods. In the first part, diffusion properties of rods with velocity reversal are discussed. In particular, we show that their diffusivity is maximal for an optimal rotational noise amplitude. The relevance of this theoretical finding for microbiological systems is corroborated by an explicit comparison to experimental data. The second part addresses collective properties of active rods. At first, a microscopic justification of alignment-interactions with nematic symmetry is presented based on a realistic model for the repulsive interaction of anisotropic rod-shaped particles. Subsequently, the large-scale properties of rods are analyzed within a hydrodynamic theory that can be systematically derived from the microscopic Langevin dynamics via the corresponding mean-field Fokker-Planck equations. Combining analytical methods, numerical continuation and particle-based simulations, the phase-diagram of self-propelled rods is constructed. The rate of velocity reversals turns out to be a central control parameter for the emergent macroscopic pattern-formation. In this regard, our results constitute a proof-of-principle in favor of the hypothesis in microbiology that velocity reversals of bacteria regulates the transitions between various self-organized patterns observed during the bacterial life cycle. [Phys. Rev. E 94 050602 (2016); New. J. Phys. 18 043009 (2016)]