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arXiv · 2503.13278

Properties of a definition of the SI second based on several optical transitions

Jérôme Lodewyck·Tetsuya Ido
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Abstract

The current definition of the SI second based on the Cs ground state hyperfine transition is expected to be replaced by a new definition based on optical frequency standards in the next decade. Several options are currently under consideration for the new definition, including a definition based on the weighted geometric mean of several transitions. In this paper, we review several properties of this option, and most notably introduce a quantitative method to set the weights of transitions, and a graphical representation of the unit that make the distinction between the definition and the realisation of the unit easier to understand.

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Jérôme Lodewyck, Tetsuya Ido. 2025-03-17. Properties of a definition of the SI second based on several optical transitions. https://arxiv.org/abs/2503.13278

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