Spinning Living Crystals of Run-and-Tumble Particles with Environmental Feedback

TL;DR

This paper demonstrates that environmental feedback can induce collective rotational order in active matter, forming living crystals with unique dynamics, especially for particles with long persistence times, revealing a new self-organization mechanism.

Contribution

It uncovers a novel environmental feedback mechanism that stabilizes living crystals with collective rotation in active matter, independent of intrinsic particle chirality or torque interactions.

Findings

Environmental feedback stabilizes large living crystals of active particles.

Collective spinning occurs for particles with long persistence times.

Dynamic environment influences self-organization and emergent behaviors.

Abstract

Collective rotations are common in active matter, enhancing cohesion, transport, and mixing. They are typically attributed to chiral non-reciprocal dynamics due to intrinsic particle chirality, torque-generating interactions among units, or geometric confinement. Here, we uncover a different mechanism for rotational order in active matter where a dynamic environment coordinates the self-organization of non-chiral active particles into living crystals exhibiting sustained collective solid-like rotations. At intermediate densities, feedback from a fluctuating landscape of passive Brownian particles stabilizes large living crystals of obstacle-avoiding run-and-tumble agents. Strikingly, this environmental feedback also produces living crystals with qualitatively distinct dynamics: collective solid-like spinning emerges for particles with long persistence times approaching ballistic motion, rather than for particles moving by conventional enhanced diffusion. Beyond revealing a new route to collective rotational order in active matter, these findings highlight the integral role of a dynamic environment in self-organization and suggest environment-mediated design principles for active materials with unconventional dynamical responses.