BPCPPDYSOE21 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 32: Posters DY - Statistical Physics, Brownian Motion and Nonlinear Dynamics

DY 32.15: Poster

Dienstag, 23. März 2021, 16:30–19:00, DYp

Clustering and 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 [1,2], 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 (WCA) potential. Furthermore, each particle is subject to a Gaussian, repulsive feedback potential [1], that depends on the difference of the particle position at the current time, x(t) and the particle position at an earlier time, x(t−τ_delay).

We show that the introduction of this type of delayed feedback leads to clustering and the emergence of collective motion in Brownian WCA systems. Depending on the particle density, the cluster size and the propagation speed can be tuned by adjusting the delay time, the strength and the range of the repulsive feedback potential.

We also analyze the effects of time-delayed feedback on the mean-squared displacement (MSD) and, thus, the diffusion of one particle, as well as the effects on the MSD in the two-dimensional many-particle system described above.

[1] S. Tarama, S. U. Egelhaaf, and H. Löwen, Phys. Rev. E 100, 022609 (2019).

[2] R. Gernert and S. H. L. Klapp, Phys. Rev. E 92, 022132 (2015).