Hyperfine Structure of $nP_{1/2}$ Rydberg States in $^{85}$Rb

TL;DR

This study precisely measures the hyperfine structure of $nP_{1/2}$ Rydberg states in $^{85}$Rb using mm-wave spectroscopy, accounting for systematic uncertainties, to aid quantum research applications.

Contribution

First precise measurement of the hyperfine coupling constant for $nP_{1/2}$ Rydberg states in $^{85}$Rb, including systematic uncertainty analysis.

Findings

Hyperfine coupling constant $A_{hfs}=1.443(31)$ GHz.

Systematic uncertainties from magnetic fields and dipole interactions quantified.

Measurement supports advancements in Rydberg-based quantum technologies.

Abstract

We measure the hyperfine structure of $nP_{1/2}$ Rydberg states using mm-wave spectroscopy on an ensemble of laser-cooled $^{85}$Rb atoms. Systematic uncertainties in our measurement from the Zeeman splittings induced by stray magnetic fields and dipole-dipole interactions between two Rydberg atoms are factored in with the obtained statistical uncertainty. Our final measurement of the $nP_{1/2}$ hyperfine coupling constant is $A_{\text{hfs}}=1.443(31)$~GHz. This measurement is useful for studies of long-range Rydberg molecules, Rydberg electrometry, and quantum simulation with dipole-dipole interactions involving $nP_{1/2}$ atoms.