2026-03-24 日本原子力研究開発機構
図１：磁性微粒子を含んだ試料を回転させた時の微粒子の自発回転
＜関連情報＞
- https://www.jaea.go.jp/02/press2025/p26032401/
- https://pubs.aip.org/aip/apl/article/128/12/122402/3384388/Persistent-rotation-of-particles-driven-by-non
非慣性ブラウン運動で駆動される粒子の持続的回転
Persistent rotation of particles driven by non-inertial Brownian motion
Maki Umeda;Hiroyuki Chudo;Masaki Imai;Mamoru Matsuo;Nana Sato;Michiyasu Mori;Sadamichi Maekawa;Eiji Saitoh
Applied Physics Letters Published:March 23 2026
DOI:https://doi.org/10.1063/5.0320016
The unidirectional spontaneous rotation of particles caused by Brownian motion rectified by the Coriolis force is reported. Fine magnetic particles dispersed in a revolving liquid were observed using the Barnett effect, and we found that the particles rotated much faster than the liquid. The observed spontaneous extra rotation is attributed to the breaking of the time-reversal symmetry of the Coriolis force, which rectified the random Brownian motion affected by viscosity. Our model considering molecular fluctuations in the medium reproduced the experiments well. The present results also suggest that all objects floating in fluids on Earth rotate spontaneously because of fluctuations.
