We demonstrate detection of a vector light shift (VLS) using the quantum lock-in method. The method offers precise VLS measurement with little affect from real magnetic field fluctuation. We detect a VLS on a Bose-Einstein condensate (BEC) of ${}^{87}\mathrm{Rb}$ atoms caused by an optical trap beam with a resolution less than 1 Hz. We demonstrate the elimination of a VLS by controlling the beam polarization to realize a long coherence time of an $F=2$ BEC in the stretched state. Quantum lock-in VLS detection should find wide application, including the study of spinor BECs, electric dipole moment searches, and precise magnetometry.

中文翻译：

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矢量光移的量子锁定检测

我们演示了使用量子锁定方法检测矢量光移（VLS）。该方法提供了精确的VLS测量，几乎不受实际磁场波动的影响。我们在Bose的Bose-Einstein冷凝物（BEC）上检测到VLS${}^{87}b$由分辨率小于1 Hz的光陷阱束引起的原子。我们展示了通过控制光束偏振来实现VLS的长相干时间，从而消除了VLS。$F=\mathrm{2个}$BEC处于拉伸状态。量子锁定VLS检测应该有广泛的应用，包括对自旋BEC的研究，电偶极矩搜索和精确的磁力分析。