Fernholz T, Krauter H, Jensen K, Sherson J F, Sørensen A S, Polzik E S
QUANTOP, Danish National Research Foundation Center for Quantum Optics, Niels Bohr Institute, Copenhagen University, DK 2100, Denmark.
Phys Rev Lett. 2008 Aug 15;101(7):073601. doi: 10.1103/PhysRevLett.101.073601. Epub 2008 Aug 12.
We demonstrate spin squeezing in a room temperature ensemble of approximately 10(12) cesium atoms using their internal structure, where the necessary entanglement is created between nuclear and electronic spins of each individual atom. This state provides improvement in measurement sensitivity beyond the standard quantum limit for quantum memory experiments and applications in quantum metrology and is thus a complementary alternative to spin squeezing obtained via interatom entanglement. Squeezing of the collective spin is verified by quantum state tomography.
我们利用约10¹²个铯原子的室温系综的内部结构演示了自旋压缩，其中在每个原子的核自旋和电子自旋之间产生了必要的纠缠。这种状态在量子存储实验以及量子计量学应用中，使测量灵敏度得到了超越标准量子极限的提升，因此是通过原子间纠缠获得的自旋压缩的一种补充替代方案。通过量子态层析成像验证了集体自旋的压缩。
