2015/06/19 by Antoine Bricard, Jean-Baptiste Caussin, Jean-Baptiste-Caussin +8 · 287 citations
Engineering · Environmental Science · Physics and Astronomy · #Active matter #Biology #Classical mechanics #Collective motion #Computer science #Crowds #Ecosystem dynamics and resilience #Mechanics #Micro and Nano Robotics #Motion (physics) #Particle Dynamics in Fluid Flows #Physics #Statistical physics #Vortex #cond-mat.soft
paper · pdf · doi:10.1038/ncomms8470
published in Nature Communications 6(1), 7470 (Nature Portfolio)
openalex publication_date 2015/06/19 · arxiv created 2015/06/26 · arxiv updated 2015/06/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Coherent vortical motion has been reported in a wide variety of populations including living organisms (bacteria, fishes, human crowds) and synthetic active matter (shaken grains, mixtures of biopolymers), yet a unified description of the formation and structure of this pattern remains lacking. Here we report the self-organization of motile colloids into a macroscopic steadily rotating vortex. Combining physical experiments and numerical simulations, we elucidate this collective behaviour. We demonstrate that the emergent-vortex structure lives on the verge of a phase separation, and single out the very constituents responsible for this state of polar active matter. Building on this observation, we establish a continuum theory and lay out a strong foundation for the description of vortical collective motion in a broad class of motile populations constrained by geometrical boundaries.