Geopotential measurements with synchronously linked optical lattice clocks
Geopotential measurements with synchronously linked optical lattice clocks
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DOI：
10.1038/nphoton.2016.159
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发表时间：
2016-08
期刊：
影响因子：
35
通讯作者：
T. Takano;M. Takamoto;I. Ushijima;N. Ohmae;T. Akatsuka;A. Yamaguchi;Y. Kuroishi;H. Munekane;B. Miyahara;H. Katori
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作者：
T. Takano;M. Takamoto;I. Ushijima;N. Ohmae;T. Akatsuka;A. Yamaguchi;Y. Kuroishi;H. Munekane;B. Miyahara;H. Katori
根据爱因斯坦的相对论，时间的流逝在引力场中发生变化。在地球上，将时钟升高1厘米会使其表观滴答速率增加1018年的1.1分之一，从而可以通过光学时钟的比较进行计时调平。 在这里，我们证明了这样的地球势测量，通过确定的高度差的主和从时钟分开15公里的不确定性为5厘米。 主时钟激光的分谐波通过电信光纤传输，以同步操作远距离时钟。在这种相位相干下工作的时钟拒绝时钟激光噪声，并促进了链接时钟和干涉仪的建议。经过半年的11次测量，确定两个钟之间的频率差为1，652.9（5.9）× 10−18，与水准测量和重力测量的独立测量结果一致。我们的系统展示了一个时钟互联网的构建模块，它可以构成“量子基准”，作为动态响应的高度参考。
According to Einstein's theory of relativity, the passage of time changes in a gravitational field,. On Earth, raising a clock by 1 cm increases its apparent tick rate by 1.1 parts in 1018, allowing chronometric levelling through comparison of optical clocks,,. Here, we demonstrate such geopotential measurements by determining the height difference of master and slave clocks separated by 15 km with an uncertainty of 5 cm. A subharmonic of the master clock laser is delivered through a telecom fibre to synchronously operate the distant clocks. Clocks operated under such phase coherence reject clock laser noise and facilitate proposals for linking clocks,and interferometers. Taken over half a year, 11 measurements determine the fractional frequency difference between the two clocks to be 1,652.9(5.9) × 10−18, consistent with an independent measurement by levelling and gravimetry. Our system demonstrates a building block for an internet of clocks, which may constitute ‘quantum benchmarks’, serving as height references with dynamic responses.