Land\'e $g$ factor measurement of $^{48}$Ti$^+$ using simultaneous co-magnetometry and quantum logic spectroscopy

TL;DR

This paper presents a quantum logic method for precise measurement of the $g$ factor of $^{48}$Ti$^+$ ions, effectively reducing magnetic field fluctuation effects and matching theoretical predictions within high accuracy.

Contribution

The authors introduce a co-magnetometry technique combined with quantum logic spectroscopy to accurately determine atomic $g$ factors, applicable to species difficult to laser cool.

Findings

Measured $g$ factor of $^{48}$Ti$^+$ with 10^{-6} uncertainty

Experimental results agree with new theoretical calculations

Method reduces systematic errors from magnetic field fluctuations

Abstract

The use of atomic systems as accurate magnetic field probes requires precise characterization of the particle's magnetic properties. Insufficient knowledge of the spatial and temporal characteristics of the external magnetic field often limits the determination of the corresponding atomic parameters. Here, we present a quantum logic scheme mitigating systematic effects caused by temporal magnetic field fluctuations through simultaneous co-magnetometry. This allows measurement of the ground state $g$ factors of a single $^{48}$Ti$^+$ ion with uncertainties at the $10^{-6}$ level. We compare experimentally determined $g$ factors with new theoretical predictions using a combination of configuration interaction (CI) and second-order many-body perturbation theory (MBPT). Theory and experiment agree within the expected level of accuracy. The scheme can be applied to many atomic species, including those that cannot be directly laser cooled.