Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 32: Atom & Ion Clocks and Metrology II
Q 32.1: Hauptvortrag
Mittwoch, 12. März 2025, 11:00–11:30, HS Botanik
Exploring fundamental constants with high-precision spectroscopy of molecular hydrogen ions — •Soroosh Alighanbari, Magnus R. Schenkel, and Stephan Schiller — Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
Molecular hydrogen ions (MHIs) have great potential for refining our understanding of fundamental physics, e.g. novel tests of CPT invariance and determination of fundamental constants (FCs). Among the MHI isotopologues, HD+ has been intensely studied, providing precise data on transitions frequencies, in agreement with ab initio predictions [1]. Homonuclear H2+ presents challenges for laser spectroscopy due to the absence of electric-dipole transitions. We succeeded in the measurement of an electric-quadrupole transition in H2+, overcoming historical limitations [2]. We have also performed a Doppler-free spectroscopy of H2+ and have measured a first-overtone transition. We have determined the spin-averaged transition frequency, enabling the derivation of a value of mp/me. The value is consistent with the recent CODATA2022 value [3] and the uncertainty is comparable. This work marks a significant step toward refining FCs and presents progress towards a test of CPT invariance through comparison of a single transition in H2+ and anti-H2+. Precision spectroscopy of a set of transitions in all MHI isotopologues enables the determination of FCs, including nuclear radii, with improved uncertainties. [1] S. Schiller, Cont. Phys. 63, 247 (2022). [2] M.R. Schenkel, et al. Nat. Phys. 20, 383 (2023). [3] S. Alighanbari, et al. Under review in Nature (2024).
Keywords: Molecular hydrogen ions; Cold and trapped molecular ions; Fundamental constants; Laser spectroscopy; proton-electron mass ratio