Observation of the Einstein-de Haas effect in a Bose-Einstein condensate.

Matsui, Hiroki; Miyazawa, Yuki; Goto, Ryoto; Nakano, Chihiro; Kawaguchi, Yuki; Ueda, Masahito; Kozuma, Mikio · Science · 2026

basic_science · Level V

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Abstract

The Einstein-de Haas effect is a phenomenon in which angular momentum is transferred from microscopic spins to mechanical rotation of a macroscopic rigid body. We report an observation of the Einstein-de Haas effect in a spinor-dipolar Bose-Einstein condensate, in which the intrinsic magnetic dipole-dipole interaction mediates coherent transfer of angular momentum from atomic spins to collective circulation of a quantum fluid. The depolarized spinor components displayed ring-shaped density distributions that were confirmed as quantized vortices through matter-wave interferometry, revealing a coherent conversion between spin and orbital angular momentum. This observation opens a pathway to exploring ground-state phases with broken chiral symmetry, spin textures, and mass circulation, as well as the Barnett effect in dipolar quantum gases.