Statistical uncertainty of 2.5×10−16for the199Hg1S0−3P0clock transition against a primary frequency standard

Abstract

High-resolution spectroscopy has been carried out on the ${}^{199}Hg$ ${}^{1}{S}_{0}\ensuremath{-}{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}$ spin and dipole forbidden transition, where the atoms are confined in a vertical one-dimensional optical lattice trap using light at the magic wavelength. We describe various characteristics of the resulting line spectra and assess the strength of the Lamb-Dicke confinement. Through a series of absolute frequency measurements of the ${}^{199}Hg$ clock transition with respect to the LNE-SYRTE primary frequency standard, recorded over a 3-month period, we demonstrate a statistical fractional uncertainty of $2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$. We include details relating to the generation of ultraviolet light at three wavelengths necessary for the experiment: 253.7 nm for cooling and detection, 265.6 nm for clock transition probing, and 362.570 nm for lattice trapping, along with further aspects related to the magic wavelength evaluation.