Berlin 2024 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 54: Active Matter V (joint session BP/DY)
DY 54.12: Talk
Friday, March 22, 2024, 12:45–13:00, H 1028
Activation fronts, fluctuations and criticality in the initiation of collective motion — •Parisa Rahmani1, Hadrien-Matthieu Gascuel2,3, Richard Bon2, and Fernando Peruani1,3 — 1LPTM, UMR 8089, CY Cergy Paris Universite, 95302 Cergy-Pontoise, France — 2CNRS, Centre de Recherches sur la Cognition Animale, F-31062 Toulouse Cedex 9, France — 3Universite Cote d'Azur, Laboratoire J. A. Dieudonne, UMR 7351 CNRS, F-06108 Nice Cedex 02, France
Collective motion is generally not a continuous process, and collectives display repeated transitions from static to moving phases. The initiation of collective motion -- of an initially static group -- is a crucial process to ensure group cohesion and behavioral synchrony that remains largely unexplored. Here, we investigate the statistical properties of the initiation of collective motion. We find that the information propagates as an activation wave, whose speed is modulated by the velocity of the active agents, where both, the magnitude and direction of the agents' velocity play a crucial role. The analysis reveals a series of distinct dynamic regimes, including a selfish regimes that allow the first informed individuals to avoid predation by swapping position with uninformed individuals. Furthermore, we unravel the existence of a generic and intimate connection between the initiation of collective motion and critical phenomena in systems with an absorbing phase, showing that in a range of agents' velocities the initiation process displays criticality. The obtained results provide an insight in the way collectives distribute, process, and respond to the local environmental cues.
Keywords: onset of collective motion; information propagation; criticality