Measurement of the ratio between g-factors of the ground states of $^{87}$Rb and $^{85}$Rb

TL;DR

This paper reports a highly precise experimental measurement of the ratio of g-factors for the ground states of two rubidium isotopes, using optical methods to improve accuracy and test quantum electrodynamics effects.

Contribution

The study provides the most accurate measurement to date of the g-factor ratio between $^{87}$Rb and $^{85}$Rb, surpassing previous precision by a factor of 50.

Findings

Measured g-factor ratio: 1.4988586(1)

Measurement accuracy exceeds previous results by 50 times

Sensitive to quantum electrodynamics effects

Abstract

The ratio between the Land\'e g-factors of the $^{87}$Rb $F=2$ and $^{85}$Rb $F=3$ ground state hyperfine levels is experimentally measured to be $g_F(87)/g_F(85) = 1.4988586(1)$, consistent with previous measurements. The g-factor ratio is determined by comparing the Larmor frequencies of overlapping ensembles of $^{87}$Rb and $^{85}$Rb atoms contained within an evacuated, antirelaxation-coated vapor cell. The atomic spins are polarized via synchronous optical pumping and the Larmor frequencies are measured by off-resonant probing using optical rotation of linearly polarized light. The accuracy of this measurement of $g_F(87)/g_F(85)$ exceeds that of previous measurements by a factor of $\approx 50$ and is sensitive to effects related to quantum electrodynamics.