Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2010 Jun 25;104(25):250801. doi: 10.1103/PhysRevLett.104.250801.
We study experimentally the application of a class of entangled states, squeezed spin states, to the improvement of atomic-clock precision. In the presence of anisotropic noise, the entanglement lifetime is strongly dependent on squeezing orientation. We measure the Allan deviation spectrum of a clock operated with a phase-squeezed input state. For averaging times up to 50 s the squeezed clock achieves a given precision 2.8(3) times faster than a clock operating at the standard quantum limit.
我们通过实验研究了一类纠缠态——压缩自旋态在提高原子钟精度方面的应用。在各向异性噪声存在的情况下，纠缠态的寿命与压缩方向密切相关。我们测量了利用相位压缩输入态运行的时钟的 Allan 偏差谱。在平均时间长达 50 秒的情况下，压缩时钟的精度比运行在标准量子极限下的时钟快 2.8(3)倍。
