The bound-electron g factor of highly charged ions provides a sensitive probe of relativistic, correlation, and quantum electrodynamic (QED) effects [1, 2]. Recent progress in both experiment and theory has highlighted the need for accurate predictions for few-electron systems, including lithiumlike ions, where interelectronic interaction plays a dominant role. In this work, we present a unified theoretical investigation of the g factor for the ground state and the lowest excited 2p1/2 and 2p3/2 states of lithiumlike ions over a broad range of nuclear charge numbers.
Interelectronic interaction is treated within bound-state QED. The first-order correction is calculated rigorously to all orders in αZ, while the two-photon-exchange term is evaluated using the Breit approximation supplemented with negative-energy contributions. Higher-order terms are obtained via the recursive formulation of perturbation theory. One-loop QED corrections, self-energy and vacuum polarization, are computed employing finite-basis B-spline techniques, and leading nuclear-recoil effects are included using effective operators. All calculations are performed within the extended Furry picture using several screening potentials to estimate the uncalculated higher-order many-electron contributions.
For the ground and excited states, we obtain significantly improved values of the interelectronic-interaction contribution, with uncertainties reduced by up to an order of magnitude compared with earlier theoretical predictions [3, 4]. For the excited 2pj states, we additionally calculate the quadratic and cubic Zeeman contributions, which become essential for the interpretation of high-precision spectroscopy [5].
Our calculations provide the most accurate theoretical predictions for the g factor of lithiumlike ions to date. The achieved precision meets the requirements of ongoing and planned high-precision measurements and strengthens the capabilities of bound-state QED tests in strong fields.
- D. A. Glazov et al., Atoms 11, 119 (2023)
- S. Sturm et al., Annalen Der Physik 525, 620 (2013)
- D. V. Zinenko et al., Phys. Rev. A 107, 032815 (2023)
- D. V. Zinenko et al., arXiv:2505.09567 (2025)
- D. von Lindenfels et al., Phys. Rev. A 87, 023412 (2013)
