2020 年 60 巻 1 号 p. 013-018
Collective motion organized by autonomous motile elements is ubiquitous across scales, from motor proteins, flagellated sperms, to animals and fishes. Such motile materials are called active matter, and collective dynamics of active matter attracts broad interest from physics and biology due to their potential in exploiting universal feature of ordered structure and dynamics in biological systems. Here, we describe collective ordered phase of bacterial vortices under confinement with designed geometries. The transition of ordered vortices can be controlled by geometric rule derived from Vicsek-style model. This finding may bring design principle of collective ordered phase of confined self-propelled particles.