Ohmae Noriaki, Bregolin Filippo, Nemitz Nils, Katori Hidetoshi
Opt Express. 2020 May 11;28(10):15112-15121. doi: 10.1364/OE.391602.
We performed the first direct measurement of the frequency ratio between a mercury (Hg) and an ytterbium (Yb) optical lattice clock to find ν/ν = 2.177 473 194 134 565 07(19) with the fractional uncertainty of 8.8 × 10. The ratio is in excellent agreement with expectations from the ratios ν/ν and ν/ν obtained previously in comparisons against a strontium (Sr) optical lattice clock. The completed closure (ν/ν)(ν/ν)(ν/ν) - 1 = 0.4(1.3) × 10 tests the frequency reproducibility of the optical lattice clocks beyond what is achievable in comparison against the current realization of the second in the International System of Units (SI).
我们首次对汞（Hg）和镱（Yb）光晶格钟之间的频率比进行了直接测量，得出ν/ν = 2.17747319413456507(19)，分数不确定度为8.8×10 。该比值与先前在与锶（Sr）光晶格钟比较中获得的ν/ν和ν/ν比值的预期结果高度吻合。完整的闭合测量（ν/ν）（ν/ν）（ν/ν） - 1 = 0.4(1.3)×10检验了光晶格钟的频率再现性，其程度超出了与国际单位制（SI）中当前秒的实现方式进行比较所能达到的水平。
