Seminar

Synchronization of 2D chiral active matter

on the 4 July 2022
14h
Bruno Ventejou (LIPhy)

We study how chirality disorder affects the collective motion ordered phases of the Vicsek model in a new model called Kuramoto-Vicsek model. We study the general case of a zero-mean Gaussian distribution of individual chiralities and the case with a zero-mean bimodal distribution. We perform microscopic simulations, and we show that the homogeneous ordered phase of the Vicsek model does not resist the introduction of a chirality disorder, whereas the coexistence phase made of traveling bands persists under finite disorder. New phases emerge in which there is a segregation between particles according to the sign of their chirality disorder. It leads to two new patterns composed of vortices and rotating packets which are turning clockwise or counterclockwise.

Then, we derive hydrodynamic equations based on the writing of a Boltzmann equation. It allows us to study the linear stability of the homogeneous phases and characterizes the finite-size effects. Also, we perform the simulation of the hydrodynamic equations and found new phases. Then we draw a new phase diagram in qualitative agreement with the one found at the microscopic level.

Mis à jour le 10 June 2022