Spiral and never-settling patterns in active suspensions

Abstract

We present a combined numerical and analytical study of pattern formation in an active system where particles align, possess a density-dependent motility, and are subject to a logistic reaction. This is a model for suspensions of reproducing bacteria, but it can also represent, in the ordered phase, actomyosin gels in vitro or in vivo. In the disordered phase, we find that motility suppression and growth compete to yield stable or blinking patterns, which, when dense enough, acquire internal orientational ordering, to yield asters or spirals. In the ordered phase, the reaction term leads to previously unobserved never-settling patterns which can provide a simple framework to understand the formation of motile and spiral patterns in actin.

5 pages, 4 figures, submitted to Physical Review Letters

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Cited by in corpus (8)

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• Viscoelastic and elastomeric active matter: Linear instability and nonlinear dynamics
• Pattern formation in polymerising actin flocks: spirals, spots and waves without nonlinear chemistry
• Weakly nonlinear analysis of pattern formation in active suspensions
• Front structure and dynamics in dense colonies of motile bacteria: Role of active turbulence