Journal Article Frequency Ratio of 199Hg and 87Sr Optical Lattice Clocks beyond the SI Limit

Yamanaka, Kazuhiro  ,  Ohmae, Noriaki  ,  Ushijima, Ichiro  ,  Takamoto, Masao  ,  Katori, Hidetoshi

114 ( 23 ) 2015-06-10 , American Physical Society
ISSN:1079-7114 (online)
We report on a frequency ratio measurement of a Hg199-based optical lattice clock referencing a Sr87-based clock. Evaluations of lattice light shift, including atomic-motion-dependent shift, enable us to achieve a total systematic uncertainty of 7.2×10−17 for the Hg clock. The frequency ratio is measured to be νHg/νSr=2.629 314 209 898 909 60(22) with a fractional uncertainty of 8.4×10−17, which is smaller than the uncertainty of the realization of the International System of Units (SI) second, i.e., the SI limit.
UTokyo Research掲載「水銀・ストロンチウム光格子時計の高精度直接比較に成功」 URI:
UTokyo Research "Highly-precise comparison of mercury and strontium optical lattice clocks" URI:

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