Search for variations of fundamental constants using atomic fountain clocks.

@article{Marion2003SearchFV,
title={Search for variations of fundamental constants using atomic fountain clocks.},
author={H. Marion and F. Pereira dos Santos and M. Abgrall and S Zhang and Y. Sortais and S. Bize and I. Maksimovic and D. Calonico and J. Gruenert and C. Mandache and P. Lemonde and G. Santarelli and P. Laurent and A. Clairon and C. Salomon},
journal={Physical review letters},
year={2003},
volume={90 15},
pages={
150801
}
}

Over five years, we have compared the hyperfine frequencies of 133Cs and 87Rb atoms in their electronic ground state using several laser-cooled 133Cs and 87Rb atomic fountains with an accuracy of approximately 10(-15). These measurements set a stringent upper bound to a possible fractional time variation of the ratio between the two frequencies: d/dt ln([(nu(Rb))/(nu(Cs))]=(0.2+/-7.0)x 10(-16) yr(-1) (1sigma uncertainty). The same limit applies to a possible variation of the quantity (mu(Rb)/mu… CONTINUE READING