Observation and measurement of the S 0 1 − P 0 3 transition in an optical lattice clock using the Hg 198 bosonic isotope
Clara Zyskind, T. Lauprêtre, Haosen Shang +4 more
We report the observation of the magnetic-field-induced ( 5 d 10 6 s 2 ) S 0 1 − ( 5 d 10 6 s 6 p ) P 0 3 transition in a bosonic isotope of mercury, Hg 198 , realized in an optical lattice clock. We characterize this Hg 198 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 Hg 198 optical lattice clock and Sr 87 . In this comparison, the Hg 198 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 Hg 198 / Sr 87 optical frequency ratio: Hg 198 / Sr 87 = 2.629 315 734 684 118 1 , with the same relative uncertainty.
arXiv:2512.04920•Physical Review Research•Jun 9, 2026•0 citations