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DY: Fachverband Dynamik und Statistische Physik
DY 24: Focus Session: Broken Symmetries in Statistical Physics - Dynamics of Odd Systems
DY 24.9: Vortrag
Mittwoch, 19. März 2025, 17:30–17:45, H43
Chirotactic response of microswimmers in 3D chiral active fluids with odd viscosity — •Yuto Hosaka1, Michalis Chatzittofi1, Ramin Golestanian1,2, and Andrej Vilfan1,3 — 1Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany — 2Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3PU, United Kingdom — 3Jožef Stefan Institute, 1000 Ljubljana, Slovenia
Odd viscosity is a property of chiral active fluids with broken time-reversal and parity symmetries. We show that the flow of such a fluid around a rotating axisymmetric body is exactly solvable [1]. Using this solution and the generalized Lorentz reciprocal theorem [2], we determine the orientational dynamics of microswimmers with an arbitrary surface slip velocity. Swimmers with a force-dipole moment exhibit precession around the axis of the odd viscosity. In addition, pushers show bimodal chirotaxis, i.e., alignment parallel or antiparallel to the axis, while pullers orbit in a plane perpendicular to it. A chiral swimmer that itself has a broken parity symmetry can exhibit unimodal chirotaxis and always align in the same direction. Since the chirotactic response of microswimmers is prohibited in 2D fluids, our theoretical results highlight the critical role of three-dimensionality in transport phenomena in chiral active fluids.
[1] Y. Hosaka, M. Chatzittofi, R. Golestanian, and A. Vilfan, Phys. Rev. Research 6, L032044 (2024).
[2] Y. Hosaka, R. Golestanian, and A. Vilfan, Phys. Rev. Lett. 131, 178303 (2023).
Keywords: odd viscosity; chiral active fluids; active matter; microswimmers; nonreciprocal response