AI 中文总结
该研究在自旋-1⁸⁷Rb玻色-爱因斯坦凝聚体中，利用自旋交换碰撞产生自旋向列压缩，观测到超越量子比特界限的量子比特贝尔关联，确立了其作为高维贝尔关联研究平台的可行性。
AI 中文摘要
量子力学允许的关联现象无法用任何经典理论解释，贝尔非定域性是这类现象中最深刻且具有操作实用性的体现。尽管非定域性已在多种平台上得到验证，但在多体系统中，其研究仍局限于量子比特系综，观测高维多体贝尔关联仍是未解决的挑战。本研究在自旋-1的⁸⁷Rb玻色-爱因斯坦凝聚体中，仅通过集体自旋可观测量构建的贝尔见证算子，观测到了量子比特的贝尔关联。利用约3.1×10⁴个原子构成的系综中的自旋交换碰撞，研究人员产生了-11.8(7)分贝的自旋向列压缩，并观测到违背程度超过N个量子比特系综可达到的最小界限，为真实多体量子比特贝尔关联提供了直接证据。本研究确立了自旋-玻色-爱因斯坦凝聚体作为多体领域高维贝尔关联研究的可行平台，证明粗粒化集体测量足以在宏观尺度上验证量子关联的维度。
英文摘要
Correlations allowed by quantum mechanics can defy any classical explanation, with Bell nonlocality standing as their most profound and operationally powerful manifestation. While nonlocality has been demonstrated across a wide range of platforms, in many-body systems it has remained limited to ensembles of qubits, leaving the observation of higher-dimensional multipartite Bell correlations an open challenge. Here we report the observation of qutrit Bell correlations in a spin-1 $^{87}$Rb Bose-Einstein condensate via the violation of a Bell witness based on collective spin observables only. Exploiting spin-exchange collisions in an ensemble of $N \simeq 3.1 \times 10^{4}$ atoms, we generate spin-nematic squeezing of $-11.8(7)$ dB and observe a violation that surpasses the minimum bound achievable by a collection of $N$ qubits, providing direct evidence of genuine multipartite qutrit Bell correlations. Our results establish spinor Bose-Einstein condensates as a viable platform for investigating high-dimensional Bell correlations in the many-body regime, and demonstrate that coarse-grained collective measurements suffice to certify the dimensionality of quantum correlations at macroscopic scales.
Comments7 + 13 pages, 3 + 1 figures
