Regensburg 2022 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 15: Delay and Feedback Dynamics

DY 15.1: Vortrag

Dienstag, 6. September 2022, 09:30–09:45, H19

Emergence of collective motion in two-dimensional colloidal systems with delayed feedback — •Robin A. Kopp and Sabine H. L. Klapp — ITP, TU Berlin, Berlin, Germany

In recent years, delayed feedback in colloidal systems has become an active and promising field of study [1], key topics being history dependence and the manipulation of transport properties. Here we study the dynamics of a two-dimensional colloidal suspension, subject to time-delayed feedback. To this end we perform overdamped Brownian dynamics simulations, where the particles interact through a Weeks-Chandler-Andersen potential. Furthermore, each particle is subject to a Gaussian, repulsive feedback potential, that depends on the difference of the particle position at the current time, and at an earlier time. We observe and quantitatively study the emergence of collective motion characterized by a nonzero mean velocity and provide a possible explanation combining single-particle and mean-field-like effects. Studying the corresponding one-particle system we obtain an understanding of the history dependence and the long-time behavior, in particular a nonzero stationary constant velocity state of the deterministic problem that translates to a constant average velocity magnitude in the stochastic system. By studying the mean square displacement we are able to point out how delayed feedback affects diffusion in the one-particle and the interacting system differently.
[1] S. A. M. Loos, S. Hermann, and S. H. L. Klapp, Entropy 23, 696 (2021)