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DY: Fachverband Dynamik und Statistische Physik
DY 59: Brownian Motion and Anomalous Diffusion
DY 59.12: Vortrag
Freitag, 22. März 2024, 12:30–12:45, BH-N 334
Depinning transition of self-propelled particles — •Arthur Straube1,2 and Felix Höfling2,1 — 1Zuse Institute Berlin — 2Fachbereich Mathematik und Informatik, Freie Universität Berlin
A depinning transition is observed in a variety of contexts when a certain threshold force must be applied to drive a system out of an immobile state. A well-studied example is the depinning of colloidal particles from a corrugated landscape, whereas its active-matter analogue has remained unexplored. Here, we discuss how active noise due to self-propulsion impacts the nature of the transition [1]: it causes a change of the critical exponent from 1/2 for quickly reorienting particles to 3/2 for slowly reorienting ones. In between these analytically tractable limits, the drift velocity exhibits a superexponential behavior as is corroborated by high-precision data. Giant diffusion phenomena occur in the two different regimes. Our predictions appear amenable to experimental tests, lay foundations for insight into the depinning of collective variables in active matter, and are relevant for any system with a saddle-node bifurcation in the presence of a bounded noise.
[1] A.V. Straube, F. Höfling, under review with Phys. Rev. Lett. (preprint arXiv:2306.09150).
Keywords: active Brownian particles; depinning transition; nonlinear response; saddle-node bifurcation under bounded noise; giant diffusion