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BP: Fachverband Biologische Physik
BP 30: Active Matter IV (joint session DY/BP/CPP)
BP 30.5: Talk
Thursday, March 21, 2024, 10:45–11:00, BH-N 334
Collective Dynamics in Dense Systems of Active Polar Disks — •yating zheng1,2, weizhen tang3, amir shee4, pawel romanczuk1,2, and cristian huepe4 — 1Humboldt-Universität zu Berlin — 2Research Cluster of Excellence 'Science of Intelligence' — 3Beijing Normal University — 4Northwestern University
We study a general model of a dense system of active polar disks with repulsive linear interactions, confined by a circular boundary. Each disk advances with a preferred self-propulsion speed and changes heading by turning around an axis of rotation located at a distance R behind its barycenter. We characterize the emerging phases and collective states as a function of R, density, and noise, for disks with isotropic and anisotropic damping disks, and a smooth or rough boundary. We find a rich phase space that combines transitions from solid to fluid states with novel R-dependent transitions from a collective state displaying localized disk rotation to a milling state around a common centre of rotation. These transitions are related to the formation of vortices that follow simple or complex dynamics depending on the boundary properties and system size. Our results demonstrate generic collective states that are expected to be observed in experimental dense systems of natural or artificial active agents in confined spaces.
Keywords: active matter; active polar disks; collective states; istropic; anisotropic