Abstract
We have measured the frequency of the extremely narrow two-photon transition in atomic hydrogen using a remote cesium fountain clock with the help of a 920 km stabilized optical fiber. With an improved detection method we obtain with a relative uncertainty of , confirming our previous measurement obtained with a local cesium clock [C. G. Parthey et al., Phys. Rev. Lett. 107, 203001 (2011)]. Combining these results with older measurements, we constrain the linear combinations of Lorentz boost symmetry violation parameters and in the standard model extension framework [D. Colladay, V. A. Kostelecký, Phys. Rev. D. 58, 116002 (1998)].
- Received 4 March 2013
DOI:https://doi.org/10.1103/PhysRevLett.110.230801
© 2013 American Physical Society
Synopsis
A Distant Second
Published 6 June 2013
By measuring hydrogen line emission with an atomic clock hundreds of kilometers away, researchers place strict limits on possible corrections to relativity.
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