Simple particles with no twist can form spinning crystals just by touching nearby dust.
April 20, 2026
Original Paper
Spinning Living Crystals of Run-and-Tumble Particles with Environmental Feedback
arXiv · 2604.16163
The Takeaway
Collective rotation in nature usually requires individual parts to be asymmetric or chiral, like a propeller. This study found that perfectly symmetric particles can self-organize into solid-like living crystals that rotate as a single unit. This spinning is fueled by feedback from the surrounding environment of smaller, passive particles. The environment effectively creates a torque that forces the entire crystal to spin. This shows that complex, life-like motion can emerge from very simple rules and environmental interactions. It offers a new way to design self-moving micro-machines and synthetic tissues that do not require complex parts.
From the 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 ro