Regensburg 2016 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Anomalous Diffusion (joint session DY/BP)

DY 22.2: Talk

Tuesday, March 8, 2016, 14:15–14:30, H47

Anomalous transport of circular swimmers in disordered structures: classical edge-state percolation — •Thomas Franosch¹, Walter Schirmacher², Benedikt Fuchs³, and Felix Höfling⁴ — ¹UIBK Innsbruck — ²Universität Mainz — ³Med.-Uni Wien — ⁴FU Berlin

Recently micron-sized self-propelled particles have been realized as model systems [1] for complex living organisms such as bacteria. If the agent is asymmetric a natural circular motion [2] emerges which yields characteristic skipping orbits when interacting with boundaries.

Here, we investigate by molecular dynamics simulations the dynamics of circular swimmers in a two-dimensional model with randomly distributed scatterers. For small radii of the swimming motion the agents orbit only around isolated clusters of scatterers, while at large radii diffusive behavior emerges. A de-localization transition occurs which is generated by percolating skipping orbits along the edges of obstacle clusters. Directly at the transition the mean-square displacements displays subdiffusive transport. The dynamic exponents differ from those of the conventional transport problem on percolating systems, thus establishing a new dynamic universality class [3]. Last, we draw an analogy to the field-induced localization transition in magnetotransport in 2D electron gases in a disordered array of antidots.

[1] F. Kümmel, et al., Phys. Rev. Lett. 110, 198302 (2013).

[2] S. van Teeffelen and H. Löwen, Phys. Rev. E 78, 020101(R) (2008).

[3] W. Schirmacher, B. Fuchs, F. Höfling, and T. Franosch, Phys. Rev. Lett. (2015, in print).