Speaker
Description
In the latest adjustment of fundamental constants [1], spectroscopy of ro-vibrational transitions in the molecular hydrogen ion HD$^+$ contributed for the first time to the determination of particle masses, in particular the proton-electron mass ratio $m_p/m_e$, the precision of which was improved by a factor of 3.5. It was also used to constrain hypothetical beyond-standard-model interactions [2,3].
After reviewing the recent experimental and theoretical advances that led to these results, I will describe ongoing work towards improving further the theoretical accuracy by calculating certain QED corrections in a fully relativistic framework, relying on a high-precision numerical resolution of the Dirac equation for the bound electron [4]. Finally, perspectives for improved determination of fundamental constants offered by extending spectroscopic measurements to other isotopologues of the molecular hydrogen ion family (H$_2^+$, D$_2^+$, …) will be discussed [5].
[1] P. J. Mohr, D. B. Newell, B. N. Taylor, and E. Tiesinga, arXiv:2409.03787
[2] M. Germann et al., Phys. Rev. Research 3, L022028 (2021).
[3] C. Delaunay et al., Phys. Rev. Lett. 130, 121801 (2023).
[4] H.D. Nogueira and J.-Ph. Karr, Phys. Rev. A 107, 042817 (2023).
[5] S. Schiller and J.-Ph. Karr, Phys. Rev. A 109, 042825 (2024).
