Regensburg 2019 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 13: Active matter I (joint session BP/CPP/DY)
BP 13.4: Vortrag
Mittwoch, 3. April 2019, 10:15–10:30, H4
Collective Responses of Magnetic Swimmers in a Poiseuille Flow — •Fanlong Meng1,2, Daiki Matsunaga2, and Ramin Golestanian1,2 — 1Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Goettingen, Germany — 2Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
Magnetotactic bacteria can be focused at the radial centre of a microfluidic channel under an external magnetic field, and found to form clusters if the external magnetic field is strong or the flow speed is large [1]. However, the underlying mechanism was missing. We show that the magnetic microswimmers (not only for magnetotactic bacteria, but also applicable to synthetic magnetic microswimmers) can form interesting large-scale clusters when the magnetic attractive interaction dominates thermal fluctuations. By applying analytic techniques and conducting Brownian dynamics simulation, we provide the critical conditions for clustering of magnetic microswimmers, which matches well with the experiment. Hydrodynamic interactions between the microswimmers are also incorporated as a generalisation. Understanding the physics of magnetic active matter will help advance the cause of studying matter out of equilibrium, and provides new insight for technological applications of synthetic magnetic microrobots (for drug delivery, solution stirring, etc.) with desired collective properties. References: [1] N. Waisbord, C. T. Lefèvre, L. Bocquet, C. Ybert, C. Cottin-Bizonne, Phys. Rev. Fluids, (2016) 1, 053203 [2] F. Meng, D. Matsunaga, R. Golestanian, Phys. Rev. Lett., (2018) 120, 188101