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New Limits to the Drift of Fundamental Constants from Laboratory Measurements
M. Fischer, N. Kolachevsky, M. Zimmermann +17
We have remeasured the absolute - transition frequency in atomic hydrogen. A comparison with the result of the previous measurement performed in 1999 sets a l…
Precision Spectroscopy of Atomic Hydrogen and Variations of Fundamental Constants
M. Fischer, N. Kolachevsky, M. Zimmermann +14
In 2003 we have measured the absolute frequency of the two-photon transition in atomic hydrogen. We observed a variati…
Cold Atom Clocks, Precision Oscillators and Fundamental Tests
S. Bize, P. Wolf, M. Abgrall +17
We describe two experimental tests of the Equivalence Principle that are based on frequency measurements between precision oscillators and/or highly accurate atomic frequency stand…
Tests of Lorentz Invariance Using a Microwave Resonator: An Update
P. Wolf, S. Bize, A. Clairon +3
The frequencies of a cryogenic sapphire oscillator and a hydrogen maser are compared to set new constraints on a possible violation of Lorentz invariance. We determine the variatio…
A clock transition for a future optical frequency standard with trapped atoms
I. Courtillot, A. Quessada, R. P. Kovacich +5
We report the first direct excitation of the strongly forbidden 5s2 1S0-5s5p 3P0 transition in 87Sr. Its frequency is 429 228 004 235 (20) kHz. A resonant laser creates a small lea…