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arXiv · 2212.14242

Absolute frequency measurement of a Yb optical clock at the limit of the Cs fountain

Irene Goti·Stefano Condio·Cecilia Clivati·Matias Risaro·Michele Gozzelino·Giovanni A. Costanzo·Filippo Levi·Davide Calonico·Marco Pizzocaro
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Abstract

We present the new absolute frequency measurement of ytterbium (171Yb) obtained at INRiM with the optical lattice clock IT-Yb1 against the cryogenic caesium (133Cs) fountain IT-CsF2, evaluated through a measurement campaign that lasted 14 months. Measurements are performed by either using a hydrogen maser as a transfer oscillator or by synthesizing a low-noise microwave for Cs interrogation using an optical frequency comb. The frequency of the 171Yb unperturbed clock transition 1S0 - 3P0 results to be 518 295 836 590 863.44(14) Hz, with a total fractional uncertainty of 2.7e-16 that is limited by the uncertainty of IT-CsF2. Our measurement is in agreement with the Yb frequency recommended by the Consultative Committee for Time and Frequency (CCTF). This result confirms the reliability of Yb as a secondary representation of the second and is relevant to the process of redefining the second in the International System of Units (SI) on an optical transition

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Irene Goti, Stefano Condio, Cecilia Clivati, Matias Risaro, Michele Gozzelino, Giovanni A. Costanzo, Filippo Levi, Davide Calonico, Marco Pizzocaro. 2022-12-29. Absolute frequency measurement of a Yb optical clock at the limit of the Cs fountain. https://doi.org/10.1088/1681-7575%2Faccbc5

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