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arXiv · 2112.08410

Small Obstacle in a Large Polar Flock

Joan Codina·Benoît Mahault·Hugues Chaté·Jure Dobnikar·Ignacio Pagonabarraga·Xia-qing Shi
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Abstract

We show that arbitrarily large polar flocks are susceptible to the presence of a single small obstacle. In a wide region of parameter space, the obstacle triggers counter-propagating dense bands leading to reversals of the flow. In very large systems, these bands interact yielding a never-ending chaotic dynamics that constitutes a new disordered phase of the system. While most of these results were obtained using simulations of aligning self-propelled particles, we find similar phenomena at the continuous level, not when considering the basic Toner-Tu hydrodynamic theory, but in simulations of truncations of the relevant Boltzmann equation.

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Joan Codina, Benoît Mahault, Hugues Chaté, Jure Dobnikar, Ignacio Pagonabarraga, Xia-qing Shi. 2021-12-15. Small Obstacle in a Large Polar Flock. https://doi.org/10.1103/physrevlett.128.218001

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