Limits to time variation of fundamental constants from comparisons of atomic frequency standards
National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex, TW11 0LW, UK
Corresponding author: email@example.com
Comparisons between frequency standards based on optical and microwave transitions in atoms and ions currently provide the most stringent laboratory limits on present-day local variation of the fundamental constants. This paper discusses the sensitivity of these frequency standards to variation of the electromagnetic and strong interactions, summarises the constraints on variation of these interactions which can be obtained from currently-available data, and discusses the magnitude of improvements in these limits which is anticipated from experiments currently underway.
© EDP Sciences, Springer-Verlag, 2008