Ultracold strontium clock: Applications to the measurement of fundamental constant variations
JILA, National Institute of Standards and Technology and University of Colorado 440 UCB, Boulder, CO, 80309-0440, USA
Corresponding author: email@example.com
We describe the application of high accuracy Sr spectroscopy to the measurement of the variation of the fundamental constants of nature. We first describe recent progress of the JILA Sr optical frequency standard, with a systematic uncertainty evaluation at the 10-16 fractional frequency level. Using recent internationally based measurements of the Sr clock frequency, we show improved constraints of gravitational and temporal changes in the fine structure constant and the electron-proton mass ratio. Finally, we describe how ultracold atomic strontium, confined in an optical lattice, can be associated into molecular dimers and be used for a model-independent measurement of the variation of the electron-proton mass ratio.
© EDP Sciences, Springer-Verlag, 2008