Self-propelled chimeras

TL;DR

This paper demonstrates the existence of chimera states in self-propelled particle systems, specifically extending the Vicsek model, revealing new behaviors where some particles synchronize while others move chaotically, with implications for real-world systems.

Contribution

It introduces the first demonstration of chimera states in self-propelled particles, extending the Vicsek model and analyzing their persistence in the infinite-particle limit.

Findings

Chimera states exist in a minimal extension of the Vicsek model.

Chimeric behavior persists in the infinite particle limit.

The behavior is driven by deterministic equations, not stochastic noise.

Abstract

The synchronization of self-propelled particles (SPPs) is a fascinating instance of emergent behavior in living and man-made systems, such as colonies of bacteria, flocks of birds, robot ensembles, and many others. The recent discovery of chimera states in coupled oscillators opens up new perspectives and indicates that other emergent behaviors may exist for SPPs. Indeed, for a minimal extension of the classical Vicsek model we show the existence of chimera states for SPPs, i.e., one group of particles synchronizes while others wander around chaotically. Compared to chimeras in coupled oscillators where the site position is fixed, SPPs give rise to new distinctive forms of chimeric behavior. We emphasize that the found behavior is directly implied by the structure of the deterministic equation of motion and is not caused by exogenous stochastic excitation. In the scaling limit of infinitely many particles, we show that the chimeric state persists. Our findings provide the starting point for the search or elicitation of chimeric states in real world SPP systems.