Polar order, shear banding, and clustering in confined active matter

Abstract

We investigate the collective behavior of sterically interacting self-propelled particles confined in a harmonic potential. Our theoretical and numerical study unveils the emergence of distinctive collective polar organizations, revealing how different levels of interparticle torques and noise influence the system. The observed phases include the shear-banded vortex, where the system self organizes in two concentric bands rotating in opposite directions around the potential center; the uniform vortex, where the two bands merge into a close packed configurations rotating uniformly as a quasi-rigid body; and the orbiting polar state, characterized by parallel orientation vectors and the cluster revolving around the potential center, without rotation, as a rigid body. Intriguingly, at lower filling fractions, the vortex and polar phases merge into a single phase where the trapped cluster breaks into smaller polarized clusters, each one orbiting the potential center as a rigid body.

12 pages, 10 figures

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Cited by in corpus (6)

• Self-Aligning Polar Active Matter
• Polarization and dynamic phases of aligning active matter in periodic obstacle arrays
• Reentrant transition to collective actuation in active solids with a polarizing field
• Collective dynamics of densely confined active polar disks with self- and mutual alignment
• Topological defects in polar active matter
• Collective actuation in active solids in the presence of a polarizing field: a systematic analysis of the dynamical regimes