BPCPPDYSOE21 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 12: Posters DY - Fluid Physics, Active Matter, Complex Fluids, Soft Matter and Glasses (joint session DY/BP)

DY 12.6: Poster

Montag, 22. März 2021, 14:00–16:30, DYp

Organizing bacterial vortex lattices by periodic obstacle arrays — •Henning Reinken¹, Sebastian Heidenreich², Markus Bär², and Sabine H. L. Klapp¹ — ¹Technische Universität Berlin, Germany — ²Physikalisch-Technische Bundesanstalt, Berlin, Germany

Recent experimental studies have shown that the turbulent vortex structures emerging in bacterial active fluids can be organized into regular vortex lattices by weak geometrical constraints such as small pillars [1]. Using a continuum-theoretical approach [2,3], we show how these artificial obstacles reorganize self-induced topological defects which guides the flow profile of the active fluid and enables the stabilization of vortex patterns with tunable properties. Beyond the stabilization of square and hexagonal lattices, we also provide a striking example of a chiral, antiferromagnetic lattice induced by arranging the obstacles in a Kagome-like array [3]. In this setup, the interplay of lattice topology, activity and length-scale selection generates a net rotational flow. Further, we explore the connections between the stabilized non-equilibrium vortex patterns and equilibrium phase transitions in classical spin lattice models, e.g., the Ising model.
[1] D. Nishiguchi, I. S. Aranson, A. Snezhko, and A. Sokolov,
[1] Nat. Commun. 9, 4486 (2018)
[2] H. Reinken, S. H. L. Klapp, M. Bär, and S. Heidenreich,
[3] Phys. Rev. E 97, 022613 (2018)
[3] H. Reinken, D. Nishiguchi, S. Heidenreich, A. Sokolov, M. Bär,
[2] S. H. L. Klapp, and I. S. Aranson, Commun. Phys. 3, 76 (2020)