SKM 2023 – wissenschaftliches Programm
DY 38.9: Vortrag
Donnerstag, 30. März 2023, 12:00–12:15, ZEU 160
Emergent pattern formation in communicating active matter — •Robert Großmann1, Zahra Mokhtari2, Robert I.A. Patterson3, and Felix Höfling2,4 — 1Institut für Physik und Astronomie, Universität Potsdam — 2Institut für Mathematik, Freie Universität Berlin — 3WIAS Berlin — 4Zuse Institut Berlin
Inspired by trail formation as observed in colonies of driver ants, for example, we study ensembles of agent particles that communicate via deposition and sensing of pheromones. These chemical traces are produced by the agents themselves and encode their current position and walking direction. Other agents passing by will then tend to align with the orientation inscribed in the pheromone traces. In the limit of short pheromone lifetime, the dynamics of this system reduces to the seminal Vicsek model and, thus, yields the formation of transversally moving bands. In the opposite limit, the effective agent-agent interaction represents a form of delayed feedback and yields the spontaneous formation of macroscopic, persistent trails, which are followed and reinforced by the agents [New J. Phys. 24 013012 (2022)]. In this talk, we present large-scale simulations of the agent model and establish the phase diagram as function of the lifetime of pheromones. We rationalize our findings by analyzing mean-field equations that are systematically derived from the stochastic particle model. Combining numerical solutions of these order parameter equations and a linear stability analysis, we show how transversal bands, common in the Vicsek model, are destabilized, giving rise to the formation of “longitudinal” trails, pointing in the mean direction of motion.