Article abstract

Nature Physics 3, 861 - 864 (2007)
Published online: 11 November 2007 | doi:10.1038/nphys778

Subject Categories: Other physics | Atomic and molecular physics | Optical physics | Techniques and instrumentation

Test of relativistic time dilation with fast optical atomic clocks at different velocities

Sascha Reinhardt1, Guido Saathoff1, Henrik Buhr1, Lars A. Carlson1, Andreas Wolf1, Dirk Schwalm1, Sergei Karpuk2, Christian Novotny2, Gerhard Huber2, Marcus Zimmermann3, Ronald Holzwarth3, Thomas Udem3, Theodor W. Hänsch3 & Gerald Gwinner4

Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but different Lorentz boosts, that tests relativistic time dilation with unprecedented precision. The approach combines ion storage and cooling with optical frequency counting using a frequency comb. 7Li+ ions are prepared at 6.4% and 3.0% of the speed of light in a storage ring, and their time is read with an accuracy of 2times10-10 using laser saturation spectroscopy. The comparison of the Doppler shifts yields a time dilation measurement represented by a Mansouri–Sexl parameter Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, or to obtain a text description, please contact, consistent with special relativity. This constrains the existence of a preferred cosmological reference frame and CPT- and Lorentz-violating 'new' physics beyond the standard model.

  1. Max-Planck-Institut für Kernphysik, 69029 Heidelberg, Germany
  2. Institut für Physik, Universität Mainz, 55099 Mainz, Germany
  3. Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
  4. Dept. of Physics & Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada

Correspondence to: Gerald Gwinner4 e-mail:


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