2014/04/07 by Remy Notermans, W. Vassen, Wim Vassen
Chemistry · Physics and Astronomy · #Atomic and Subatomic Physics Research #Atomic physics #Chemistry #Cold Atom Physics and Bose-Einstein Condensates #Crystallography #Degenerate energy levels #Dipole #Energy (signal processing) #Ion #Ionization #Metastability #Physics #Quantum mechanics #Quantum, superfluid, helium dynamics #Spectroscopy #cond-mat.quant-gas #physics.atom-ph #quant-ph
paper · pdf · doi:10.1103/physrevlett.112.253002
published as Phys. Rev. Lett. 112, 253002 (2014) · 10 pages, 13 figures, paper includes supplemental information. Paper submitted for review
arxiv created 2014/04/07 · openalex publication_date 2014/06/25 · arxiv updated 2014/06/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have measured the forbidden 2 3S1\ensuremath→2 1P1 transition at 887 nm in a quantum degenerate gas of metastable 4He atoms confined in an optical dipole trap. The determined transition frequency is 338 133 594.4 (0.5) MHz, from which we obtain an ionization energy of the 2 1P1 state of 814 709 148.6 (0.5) MHz. This ionization energy is in disagreement by >3\ensuremathσ with the most accurate quantum electrodynamics calculations available. Our measurements also provide a new determination of the lifetime of the 2 1P1 state of 0.551 (0.004)stat (_\ensuremath-0.000+0.013)syst ns, which is the most accurate determination to date and in excellent agreement with theory.