Frequency Ratio of Two Optical Clock Transitions in Yb+171 and Constraints on the Time Variation of Fundamental Constants

Author(s): R. M. Godun, P. B. R. Nisbet-Jones, J. M. Jones, S. A. King, L. A. M. Johnson, H. S. Margolis, K. Szymaniec, S. N. Lea, K. Bongs, and P. Gill

Single-ion clocks yield new limits on how much the proton-to-electron mass ratio and the fine structure constant change over time.

[Phys. Rev. Lett. 113, 210801] Published Mon Nov 17, 2014