Abstract
A 190-day comparison of the optical frequencies defined by an optical cavity and a molecular electronic transition is analyzed for the velocity independence of the speed of light (Kennedy-Thorndike test) and the universality of the gravitational redshift. The modulation of the laboratory velocity and the gravitational potential were provided by Earth’s orbital motion around the Sun. We find a velocity-dependence coefficient of , 3 times lower compared to the best previous test. Alternatively, the data confirm the gravitational redshift for an electronic transition at the level. Prospects for significant improvements of the tests are discussed.
- Received 19 June 2001
DOI:https://doi.org/10.1103/PhysRevLett.88.010401
©2001 American Physical Society