Swarming and Flocking Unified Through Behavioral Imperfections

Abstract: Natural flocks (aligned) and swarms (non-aligned) both exhibit features of criticality, challenging their treatment as two ends of the same phase transition. We present a model for the cohesion of active individuals, who spontaneously self-assemble into a near-critical state, whether aligned or not. In our framework, these individuals move in open space and possess differing self-propelling velocities. The emerging velocity fluctuations, shown to be correlated and scale-invariant, are triggered by inherent noise rooted in individual imperfections. Using the finite-size scaling theory, we show that our system exhibits criticality features observed in groups of midges and starlings.