Density-polarity coupling in confined active polar films: asters, spirals, and biphasic orientational phases

Abstract

Topological defects in active polar fluids can organise spontaneous flows and influence macroscopic density patterns. Both of them play, for example, an important role during animal development. Yet the influence of density on active flows is poorly understood. Motivated by experiments on cell monolayers confined to discs, we study the coupling between density and polar order for a compressible active polar fluid in presence of a +1 topological defect. As in the experiments, we find a density-controlled spiral-to-aster transition. In addition, biphasic orientational phases emerge as a generic outcome of such coupling. Our results highlight the importance of density gradients as a potential mechanism for controlling flow and orientational patterns in biological systems.

References in corpus (7)

• Topological active matter
• Defect dynamics in active nematics
• Spontaneous Circulation of Confined Active Suspensions
• Generic phase diagram of active polar films
• Complex Spontaneous Flows and Concentration Banding in Active Polar Films
• Insensitivity of active nematic dynamics to topological constraints
• Patterning of morphogenetic anisotropy fields

Cited by in corpus (2)

• The importance of being discrete -- An agent-based model for active nematics and more
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