2011/07/15 by Christian G. Parthey, Arthur Matveev, Jānis Alnis +16 · 419 citations
Chemistry · Physics and Astronomy · #Advanced Frequency and Time Standards #Analytical Chemistry (journal) #Atomic and Subatomic Physics Research #Atomic physics #Chemistry #Cold Atom Physics and Bose-Einstein Condensates #Hydrogen #Hydrogen atom #Hyperfine structure #Physics #Quantum mechanics #Spectroscopy #physics.atom-ph
paper · pdf · doi:10.1103/physrevlett.107.203001
published in Physical Review Letters 107(20), 203001 (American Physical Society) · 5 pages, 4 figures
arxiv created 2011/07/15 · openalex publication_date 2011/11/11 · arxiv updated 2011/11/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have measured the 1S-2S transition frequency in atomic hydrogen via two-photon spectroscopy on a 5.8 K atomic beam. We obtain f(1S-2S) = 2,466,061,413,187,035 (10) Hz for the hyperfine centroid, in agreement with, but 3.3 times better than the previous result [M. Fischer et al., Phys. Rev. Lett. 92, 230802 (2004)]. The improvement to a fractional frequency uncertainty of 4.2 × 10(-15) arises mainly from an improved stability of the spectroscopy laser, and a better determination of the main systematic uncertainties, namely, the second order Doppler and ac and dc Stark shifts. The probe laser frequency was phase coherently linked to the mobile cesium fountain clock FOM via a frequency comb.