Flocking without alignment interactions in attractive active Brownian particles

Abstract

Within a simple model of attractive active Brownian particles, we predict flocking behavior and challenge the widespread idea that alignment interactions are necessary to observe this collective phenomenon. Here, we show that even non-aligning attractive interactions can lead to a flocking state. Monitoring the velocity polarization as the order parameter, we reveal the onset of a first-order transition from a disordered phase, characterized by several small clusters, to a flocking phase, where a single flocking cluster is emerging. The scenario is confirmed by studying the spatial connected correlation function of particle velocities, which reveals scale-free behavior in flocking states and exponential-like decay for non-flocking configurations. Our predictions can be tested in microscopic and macroscopic experiments showing flocking, such as animals, migrating cells, and active colloids.

References in corpus (19)

• Novel type of phase transition in a system of self-driven particles
• Interaction Ruling Animal Collective Behaviour Depends on Topological rather than Metric Distance: Evidence from a Field Study
• Motility-Induced Phase Separation
• Physics of Microswimmers - Single Particle Motion and Collective Behavior
• Collective motion of self-propelled particles interacting without cohesion
• Effective Interactions in Active Brownian Suspensions
• From Phase to Micro-Phase Separation in Flocking Models: The Essential Role of Non-Equilibrium Fluctuations
• Spontaneous velocity alignment in Motility-induced Phase Separation
• Multidimensional Stationary Probability Distribution for Interacting Active Particles
• Perspective: Nonequilibrium glassy dynamics in dense systems of active particles
• Motility-induced phase separation and coarsening in active matter
• Morphology of clusters of attractive dry and wet self-propelled spherical particle suspensions
• Applicability of Effective Pair Potentials for Active Brownian Particles
• Non-Equilibrium Surface Tension of the Vapour-Liquid Interface of Active Lennard-Jones Particles
• Non-negative Interfacial Tension in Phase-Separated Active Brownian Particles
• The Parental Active Model: a unifying stochastic description of self-propulsion
• Self-assembly of active amphiphilic Janus particles
• Lane formation in a driven attractive fluid
• Phase separation of active Brownian particles in two dimensions: Anything for a quiet life