Exotic Quantum States in Spin‐1 Bose–Einstein Condensate with Spin‐Orbit coupling in Concentric Annular Traps

Spin‐orbit coupling (SOC) has broad relevances and its interplay with other interactions and potential geometry may induce novel quantum states. This work explores exotic quantum states emerging in the ground state (GS) of a strongly‐correlated spin‐1 Bose–Einstein condensate confined in 2D concentric annular traps with SOC. In the antiferromagnetic case, the GS density manifests various patterns of distributions, including facial‐makeup states, petal states, topological fissure states, multiple‐half‐ring states and property‐distinguished vertical and horizontal stripe states. A peculiar phenomenon of density‐phase separation is noticed in the sense that the variations of density and phase tend to be independent. In ferromagnetic case, the GS exhibits a semi‐circular or half‐disk status of density embedded with vortices and antivortices. The spin distribution can self‐arrange into an array of half‐skyrmions and a half‐antiskyrmion fence separating vortex‐antivortex pairs is also found. This study indicates that one can manipulate the emergence of exotic quantum states and the locations of the topological defects via the interplay of the SOC, interactions and potential geometry and the abundant state variations might also provide potential resources for quantum metrology.