Swirling transition with social interactions: Analyzed by a sixth-order Landau-type model (a)

Abstract

Swirling groups of animals or bacteria are a common phenomenon in nature. It is thought that this collective organization occurs in the vicinity of a continuous transition between dynamic states to ensure robust group cohesion while allowing for high sensitivity to outside stimuli like predators. Here, we present Brownian dynamics simulations of active particles with social interactions which can form stable swirls. We observe a transition between swarming and swirling states and analyze these using a sixth-order Landau-type model. Our results suggest that the transition is weakly discontinuous. However, by lowering the rotational diffusion coefficient, it becomes continuous.