Title: Modeling Collective Responses of Active Matter

Speaker: Prof. Fanlong Meng , Institute of Theoretical Physics

Time: Mar. 25 (Friday), 10:00

Place: Rm M830, IOP-CAS

Abstract:

 I will present our works on understanding the collective dynamics of three active matter systems: magnetic microswimmers in a microfluidic channel, active nematics, and cilia in presence of a wall. (1) Magnetic microswimmers in a microfluidic channel can show different collective responses by external magnetic stimuli: radial focusing, longitudinal clustering and radial BEC. By applying analytic techniques and conducting Brownian dynamics simulation, we provide the critical conditions for these different dynamic modes of the microswimmers. (2) 2D and 3D active nematics can exhibit interesting scalings, and we try to understand this from how hydrodynamics active nematics work in presence of confinements. (3) Beating cilia can coordinate with each other, beating in the form of a metachronal wave. We construct an analytical theory to deal with the emergent dynamics of an infinite array of cilia to understand the physical mechanism underlying the collective beating of the cilia. By performing analytical analyses, we provide the dispersion relation of the system, and predict the achievable stable wave vector region.

References:

[1].FM, D. Matsunaga, and R. Golestanian, "Clustering of magnetic swimmers in a Poiseuille flow", Physical Review Letters 120, 188101 (2018); FM, D. Matsunaga, B. Mahault, and R. Golestanian, "Magnetic Microswimmers Exhibit Bose-Einstein-Like Condensation", Physical Review Letters 126, 078001 (2021).

[2].B. Martínez-Prat#, R. Alert#, FM, J. Ignes-Mullol, J.-F. Joanny, J. Casademunt, R. Golestanian, and F. Sagues, "Scaling Regimes of Active Turbulence with External Dissipation", Physical Review X, 11, 031065 (2021).

[3].FM#, R. Bennett#, N. Uchida, and R. Golestanian, "Conditions for metachronal coordination in arrays of model cilia",  Proceedings of the National Academy of Sciences USA, 118, e2102828118 (2021).