Berlin 2018 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 80: Brownian Motion and Transport
DY 80.5: Vortrag
Freitag, 16. März 2018, 11:00–11:15, BH-N 128
Dynamic mode locking in a driven colloidal system — Michael Juniper1, Urs Zimmermann2, •Arthur Straube3, Rut Besseling4, Dirk Aarts1, Hartmut Löwen2, and Roel Dullens1 — 1Department of Chemistry, University of Oxford, UK — 2Institute of Theoretical Physics, Heinrich-Heine-Universität Düsseldorf, Germany — 3Freie Universität Berlin, Institute of Mathematics, Berlin, Germany — 4InProcess-LSP, Oss, The Netherlands
We examine both experimentally and theoretically the microscopic dynamics underlying mode locking in a colloidal system [1,2]. We first look at a colloidal particle driven by a modulated force over a sinusoidal optical potential energy landscape. Coupling between the competing frequencies of the modulated drive and that of particle motion over the periodic landscape leads to synchronization of particle motion into discrete modes, manifesting as Shapiro steps in the average particle velocity. State diagrams from experiment, simulation, and theory agree well. Further, we use this approach to examine the enhancement of mode locking in a flexible chain of magnetically coupled particles, which we ascribe to breathing modes caused by mode-locked density waves. Finally, we demonstrate that an emergent density wave in a static colloidal chain mode locks as a quasi-particle, with microscopic dynamics analogous to those seen for a single particle.
[1] M. Juniper, A. Straube, R. Besseling, D. Aarts, R. Dullens, Nat. Commun. 6, 7187 (2015)
[2] M. Juniper, U. Zimmermann, A. Straube, R. Besseling, D. Aarts, H. Löwen, R. Dullens, New J. Phys. 19, 013010 (2017)