Shape anisotropy governs organization of active rods: Swarming, turbulence, flocking, and jamming
Summary
Shape anisotropy of individual building blocks plays a crucial role in creating exotic structures and controlling phase behavior in equilibrium systems. We present a combined experimental and simulation study in which we used light-driven self-propelled rods to investigate when and how shape-induced alignment and steric and hydrodynamic interactions govern self-organization. Varying rod aspect ratio and area fraction causes the system to evolve from active Brownian motion to swarming, acti
Content
# Shape anisotropy governs organization of active rods: Swarming, turbulence, flocking, and jamming
*Published: 2026 Apr 9*
Shape anisotropy of individual building blocks plays a crucial role in creating
exotic structures and controlling phase behavior in equilibrium systems. We
present a combined experimental and simulation study in which we used
light-driven self-propelled rods to investigate when and how shape-induced
alignment and steric and hydrodynamic interactions govern self-organization.
Varying rod aspect ratio and area fraction causes the system to evolve from
active Brownian motion to swarming, active turbulence, flocking, large clusters,
and jamming. A state diagram summarizes emergent behaviors, and spatiotemporal
analyses reveal distinct giant-number fluctuations across states. This minimal
model offers insight into the self-organization of biological rodlike
microswimmers, enabling the decoupling of physical from biological mechanisms.
Our results provide design rules for programmable synthetic active materials and
highlight parallels with bacterial swarms and other biological assemblies.
DOI: 10.1126/science.ady7618