New Limits on Coupling of Fundamental Constants to Gravity Using ${}^{87}$Sr Optical Lattice Clocks

Abstract

The ${}^1{\mathrm{S}}_0$-${}^3{\mathrm{P}}_0$ clock transition frequency ${\nu }_{\text{Sr}}$ in neutral ${}^{87}$Sr has been measured relative to the Cs standard by three independent laboratories in Boulder, Paris, and Tokyo over the last three years. The agreement on the $1\times 10^{-15}$ level makes ${\nu }_{\text{Sr}}$ the best agreed-upon optical atomic frequency. We combine periodic variations in the ${}^{87}$Sr clock frequency with ${}^{199}$Hg${}^{+}$ and H-maser data to test Local Position Invariance by obtaining the strongest limits to date on gravitational-coupling coefficients for the fine-structure constant $\alpha$, electron-proton mass ratio $\mu$ and light quark mass. Furthermore, after ${}^{199}$Hg${}^{+}$, ${}^{171}$Yb${}^{+}$ and H, we add ${}^{87}$Sr as the fourth optical atomic clock species to enhance constraints on yearly drifts of $\alpha$ and $\mu$.

Published version. 4 pages, 4 figures

References in corpus (1)

• Variation of fundamental constants: theory and observations

Cited by in corpus (2)

• Varying Alpha: New Constraints from Seasonal Variations
• Eotvos bounds on couplings of fundamental parameters to gravity