Possibility of an optical clock using the $6{}^1{S}_0\to 6{}^3{P}_0^o$ transition in ${}^{171,173}\mathrm{Yb}$ atoms held in an optical lattice

We report calculations assessing the ultimate precision of an atomic clock based on the 578 nm $6{}^1{S}_0\to 6{}^3{P}_0$ transition in Yb atoms confined in an optical lattice trap. We find that this transition has a natural linewidth less than 10 mHz in the odd Yb isotopes, caused by hyperfine coupling. The shift in this transition due to the trapping light acting through the lowest order ac polarizability is found to become zero at the magic trap wavelength of about 752 nm. The effects of Rayleigh scattering, multipole polarizabilities, vector polarizability, and hyperfine induced electronic magnetic moments can all be held below 1 mHz (about one part in ${10}^{18}).\mathrm{}$ In the case of the hyperpolarizability, however, larger shifts due to nearly resonant terms cannot be ruled out without an accurate measurement of the magic wavelength.