Gregarious vs Individualistic Behavior in Vicsek Swarms and the Onset of First-Order Phase Transitions

Abstract

The Standard Vicsek Model (SVM) is a minimal nonequilibrium model of self-propelled particles that appears to capture the essential ingredients of critical flocking phenomena. In the SVM, particles tend to align with each other and form ordered flocks of collective motion; however, perturbations controlled by a noise term lead to a noise-driven, continuous order-disorder phase transition. In this work, we extend the SVM by introducing a parameter $\alpha$ that allows particles to be individualistic instead of gregarious, i.e. to choose a direction of motion independently of their neighbors. By focusing on the small-noise regime, we show that a relatively small probability of individualistic motion (around 10%) is sufficient to drive the system from a Vicsek-like ordered phase to a disordered phase. Despite the fact that the $\alpha -$extended Model preserves the O(n) symmetry, the interaction range, as well as the dimensionality of the underlying SVM, this novel phase transition is found to be discontinuous (first-order), an intriguing manifestation of the richness of the nonequilibrium flocking/swarming phenomenon.

13 pages, 6 figures. To appear in Physica A

References in corpus (7)

• Novel type of phase transition in a system of self-driven particles
• Collective motion
• Collective motion of self-propelled particles interacting without cohesion
• Noise-Induced Transition from Translational to Rotational Motion of Swarms
• New aspects of the continuous phase transition in the scalar noise model (SNM) of collective motion
• Phase transitions in swarming systems: A recent debate
• Criticality and the Onset of Ordering in the Standard Vicsek Model

Cited by in corpus (7)

• Self-propelled hard disks: implicit alignment and transition to collective motion
• How many dissenters does it take to disorder a flock?
• Motile dissenters disrupt the flocking of active granular matter
• Swarming transitions in hierarchical societies
• Emergence of a single cluster in Vicsek's model at very low noise
• Active matter clusters at interfaces
• Self-Propelled Collective Motion with Multiplicative Scalar Noise