Method for Precision Test of Fine Structure Constant Variation with Optical Frequency References

Abstract

A new method for examining the possible space-time variation of the fine structure constant ($\alpha$) is proposed. The technique uses a relatively simple measurement with an optical resonator to compare atom-stabilized optical frequency references. This method does not require that the exact frequency of each reference be measured, and has the potential to yield more than a 1000-fold improvement in experimental sensitivity to changes in $\alpha$. A specific realization of an experiment using this method is discussed which can approach the precision of ${\dot\alpha/\alpha}\sim10^{-18}/\tau$, where $\tau$ is the measurement time. Moreover, for this specific realization, a measurement of ${\dot\alpha/\alpha}\sim10^{-15}/{\rm yr}$ as a near-term goal is realistic.