Improved Bound-Electron g -Factor Theory through Complete Two-Loop QED Calculations
Year: 2025
Type: article
Abstract: The two-loop self-energy correction to the bound-electron g factor in hydrogenlike ions is investigated, taking into account the electron-nucleus interaction exactly. This all-order calculation is required to improve the total theoretical uncertainty of the g factor, which is limited by the fact that two-loop self-energy corrections have only been calculated so far in the form of an expansion in Zα. Here, Z is the nuclear charge number and α is the fine-structure constant. In this work, we report calculations of the last missing parts of the total two-loop self-energy correction, exactly in Zα. We apply our theory to the recently measured g factor of the hydrogenlike ^{118}Sn^{49+} ion [J. Morgner et al., Nature (London) 622, 53 (2023)NATUAS0028-083610.1038/s41586-023-06453-2] and, with a factor of 8, improve the accuracy of its state-of-the-art theoretical value by almost one order of magnitude, enabling more detailed tests of quantum electrodynamics and new physics in strong fields.
Source: Physical Review Letters
Authors: B. Sikora, V. A. Yerokhin, C. H. Keitel, Z. Harman
Institution: Max Planck Institute for Nuclear Physics
Language: English
Topic: Atomic and Molecular Physics
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,750
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W4408904962