2004/02/29 by E. Peik, B. Lipphardt, H. Schnatz +4 · 4 citations
Physics and Astronomy · #Advanced Fiber Laser Technologies #Advanced Frequency and Time Standards #Atomic and Subatomic Physics Research #physics.atom-ph
paper · pdf · doi:10.1103/physrevlett.93.170801
published as Phys. Rev. Lett. 93, 170801 (2004) · 4 pages, 3 figures, references updated
openalex publication_date 2004/10/18 · arxiv created 2004/10/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
The comparison of different atomic transition frequencies over time can be used to determine the present value of the temporal derivative of the fine structure constant \ensuremathα in a model-independent way without assumptions on constancy or variability of other parameters, allowing tests of the consequences of unification theories. We have measured an optical transition frequency at 688 THz in 171Yb+ with a cesium atomic clock at 2 times separated by 2.8 yr and find a value for the fractional variation of the frequency ratio fYb/fCs of (\ensuremath-1.2\ifmmode±\else\textpm\fi4.4)\ifmmode×\else\texttimes\fi10^\ensuremath-15 yr^\ensuremath-1, consistent with zero. Combined with recently published values for the constancy of other transition frequencies this measurement sets an upper limit on the present variability of \ensuremathα at the level of 2.0\ifmmode×\else\texttimes\fi10^\ensuremath-15 yr^\ensuremath-1 (1\ensuremathσ), corresponding so far to the most stringent limit from laboratory experiments.