Probing spontaneously formed spin textures in a europium spinor dipolar gas via tilted-axis spin separation

When a spin-polarized atomic Bose–Einstein condensate (BEC) is placed in a weak magnetic field, the coherent transfer of angular momentum from atomic spins to macroscopic motion manifests as the Einstein–de Haas effect [1]. In previous observations using europium BEC [2], spinor components were separated along the initial polarization axis, providing only population information without access to local spin orientation due to the loss of relative phase. Here, we performed spin separation along quantization axes tilted by 16° toward the imaging axis from the initial direction. The spatial distribution observed in the m=−6 component reveals a characteristic spin texture featuring tangential spin components, which can be attributed to the precession of atomic spin around the local magnetic fields. Since the spin in the flower phase—one of the ground-state quantum phases—has no tangential component, our method enables a clear distinction between the dynamical texture and the equilibrium spin configurations.

[1] Y. Kawaguchi et al., Phys. Rev. Lett. 96, 080405 (2006).

[2] H. Matsui et al., arXiv:2504.17357 (2025).