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Observation and measurement of the S01−P03 transition in an optical lattice clock using the Hg198 bosonic isotope

Clara Zyskind, Thomas Lauprêtre, Haosen Shang, Benjamin Pointard, Rodolphe Le Targat, Jérôme Lodewyck, and Sébastien Bize*

  • *Contact author: sebastien.bize@obspm.fr
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Phys. Rev. Research 8, 033366 – Published 28 September, 2026

DOI: https://doi.org/10.1103/q28c-kb61

Abstract

We report the observation of the magnetic-field-induced (5d106s2)S01−(5d106s6p)P03 transition in a bosonic isotope of mercury, Hg198, realized in an optical lattice clock. We characterize this Hg198 clock transition at 265.6 nm, determining key features such as the quadratic Zeeman shift, the probe light shift, and the magic frequency. We also report a comparison between the Hg198 optical lattice clock and Sr87. In this comparison, the Hg198 clock has a relative frequency stability of 6×10−16/τ/s and a total relative systematic uncertainty of 6.9×10−16. This comparison yields the first direct determination of the Hg198/Sr87 optical frequency ratio: Hg198/Sr87=2.6293157346841181, with the same relative uncertainty.

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Phys. Rev. Research 8, 033366– Published 28 September, 2026
  • Received 30 November 2025
  • Revised 22 April 2026
  • Accepted 9 June 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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