Regensburg 2019 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 26: Active matter I (joint session BP/CPP/DY)
DY 26.2: Talk
Wednesday, April 3, 2019, 09:45–10:00, H4
Light-dependent microbial motility induces pattern formation in confinement — •Alexandros Fragkopoulos1, Johannes Frey1, Flora-Maud Le Menn1, Jeremy Vachier1, Michael Wilczek1, Marco Mazza1,2, and Oliver Bäumchen1 — 1Max Planck Institute for Dynamics and Self-Organization, D-37077 Göttingen, Germany — 2Loughborough University, Loughborough LE11 3TU, United Kingdom
A collection of active swimmers can undergo complex dynamics due to hydrodynamic and steric interactions. For sufficiently concentrated suspensions, it is possible to form large-scale concentration patterns, where the active suspension separates into regions of high and low particle concentrations. Here we present that a collection of Chlamydomonas reinhardtii cells, a unicellular soil-dwelling microalgae and a model organism of puller-type microswimmers, form patterns of high and low cell density regions in confinement and under specific light conditions. We find that the motility of the cells differs significantly for different light intensities and cell densities, which regulate the pattern formation in such active suspensions. In addition, we observe that the emerged pattern follows the shape of the confinement that encloses the motile cells, which indicates that the boundaries enclosing the motile cells play a crucial role for pattern formation. Finally, by performing active Brownian dynamics simulations of active particles with the observed motility characteristics, we show that we can reproduce the experimentally observed patterns.