Collective motion of self-propelled particles interacting without cohesion

TLDR

The study investigates Vicsek‑style self‑propelled particle models in two and three dimensions. The authors analyze the models by examining the onset of collective motion and the properties of the ordered, collectively moving phase. They find that the transition to collective motion is discontinuous, that near the transition high‑density solitary waves dominate, while far from it the system becomes a statistically homogeneous ordered phase exhibiting strong density fluctuations, superdiffusion, and intermittency.

Abstract

We present a comprehensive study of Vicsek-style self-propelled particle models in two and three space dimensions. The onset of collective motion in such stochastic models with only local alignment interactions is studied in detail and shown to be discontinuous (first-order-like). The properties of the ordered, collectively moving phase are investigated. In a large domain of parameter space including the transition region, well-defined high-density and high-order propagating solitary structures are shown to dominate the dynamics. Far enough from the transition region, on the other hand, these objects are not present. A statistically homogeneous ordered phase is then observed, which is characterized by anomalously strong density fluctuations, superdiffusion, and strong intermittency.