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arXiv · 2008.00723

Absolute frequency of $^{87}\mathrm{Sr}$ at $1.8 \times 10^{-16}$ uncertainty by reference to remote Primary Frequency Standards

Nils Nemitz·Tadahiro Gotoh·Fumimaru Nakagawa·Hiroyuki Ito·Yuko Hanado·Tetsuya Ido·Hidekazu Hachisu
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Abstract

The optical lattice clock NICT-Sr1 regularly reports calibration measurements of the international timescale TAI. By comparing measurement results to the reports of eight Primary Frequency Standards, we find the absolute frequency of the $^{87}\mathrm{Sr}$ clock transition to be f(Sr)=$429\,228\,004\,229\,873.082(76)$, with a fractional uncertainty of less than 1.8x10$^{-16}$ approaching the systematic limits of the best realization of SI second. Our result is consistent with other recent measurements and further supported by the loop closure over the absolute frequencies of $^{87}\mathrm{Sr}$, $^{171}\mathrm{Yb}$ and direct optical measurements of their ratio.

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Nils Nemitz, Tadahiro Gotoh, Fumimaru Nakagawa, Hiroyuki Ito, Yuko Hanado, Tetsuya Ido, Hidekazu Hachisu. 2020-08-03. Absolute frequency of $^{87}\mathrm{Sr}$ at $1.8 \times 10^{-16}$ uncertainty by reference to remote Primary Frequency Standards. https://doi.org/10.1088/1681-7575/abc232

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