Speaker
Description
The Standard Model of particle physics very successfully describes a broad range of physical phenomena but remains incomplete. Therefore, it is of utmost importance to verify its foundational theories as precisely as possible in all their facets, especially in extreme situations.
The ALPHATRAP experiment is a dedicated cryogenic Penning-trap apparatus, designed for this exact purpose. At ALPHATRAP it is possible to measure the g-factor of bound electrons ranging from light molecular hydrogen ions to heavy highly charged ions using widely applicable nondestructive single ion spectroscopy techniques [1].
Here, I will present the latest measurements of the bound electron g factor in H-like, Li-like, and B-like tin ion (Z=50) with 0.5 parts-per-billion precision. There, extreme electric field strength up to 1E15 V/cm act on the electron, magnifying QED effects and allowing to test them to highest precision via the comparison with theory predictions [2,3].
Furthermore, I will show the recent spectroscopy results regarding the hyperfine spectroscopy of a single HD+ ion, which probes the fundamental spin-spin interaction theory [4]. The precise knowledge of the hyperfine structure of HD+ is very important since it contributes to the determination of the fundamental masses of the electron, proton and deuteron via high precision HD+ laser spectroscopy results [5]. Further measurements are particularly valuable to resolve the current 9-sigma discrepancy between hyperfine theory and experiment [6].
Finally, I will present the current status of the rovibrational laser spectroscopy on a single trapped HD+, which is essential for future high-precision matter-antimatter comparisons [7].
[1] Sturm et al. Eur. Phys. J. Spec. Top. 227, 1425 (2019).
[2] Morgner et al. Nature 622, 5357 (2023).
[3] Morgner et al. Phys. Rev. Lett. 134, 123201 (2025).
[4] König et al. Phys. Rev. Lett. 134, 163001 (2025).
[5] Karr and Koelemeij Mol. Phys. 121 2216081 (2023).
[6] Haidar et al. Phys. Rev. A 106, 042815 (2022)
[7] Myers Phys. Rev. A 98, 010101 (2018).
