New Limits on the Drift of Fundamental Constants from Laboratory Measurements

Abstract

We have remeasured the absolute $1S$-$2S$ transition frequency ${\nu }_{\mathrm{H}}$ in atomic hydrogen. A comparison with the result of the previous measurement performed in 1999 sets a limit of $(-29\pm 57)\mathrm{Hz}$ for the drift of ${\nu }_{\mathrm{H}}$ with respect to the ground state hyperfine splitting ${\nu }_{\mathrm{Cs}}$ in ${}^{133}\mathrm{Cs}$. Combining this result with the recently published optical transition frequency in ${}^{199}\mathrm{Hg}^{+}$ against ${\nu }_{\mathrm{Cs}}$ and a microwave ${}^{87}\mathrm{Rb}$ and ${}^{133}\mathrm{Cs}$ clock comparison, we deduce separate limits on $\dot{\alpha }/\alpha =(-0.9\pm 2.9)\times {10}^{-15}{\mathrm{yr}}^{-1}$ and the fractional time variation of the ratio of Rb and Cs nuclear magnetic moments ${\mu }_{\mathrm{Rb}}/{\mu }_{\mathrm{Cs}}$ equal to $(-0.5\pm 1.7)\times {10}^{-15}{\mathrm{yr}}^{-1}$. The latter provides information on the temporal behavior of the constant of strong interaction.