Atomic Clocks and the Search for Variation of Fundamental Constants
Recent advances in atomic and optical physics have led to unprecedented improvements in the optical frequency metrology leading to more sensitive quantum-based standards for various applications including search for variation of fundamental constants. The modern theories directed toward unifying gravitation with the three other fundamental interactions suggest variation of the fundamental constants in an expanding universe. Some atomic systems exhibit much higher sensitivity to the variation of fine-structure constant a allowing more precise tests of the temporal a-variation and possible tests of the spatial variation. I will review the present status of the laboratory and astrophysical searches for variation of the fundamental constants, and outline the proposals for future developments of optical frequency standards needed for the next generation of such tests.
Further improvement of the optical frequency standards requires understanding of the effect of the blackbody radiation (BBR) shift on the transition frequency. I will report the development of a new method of first-principles calculation that reduced the relative uncertainty due to the BBR shift at 300K in Al+ to 4×10-19 as well as significantly improved knowledge of BBR shift in other systems. The same methodology can be used for better understanding of alkaline-earth and other more complicated atoms such as Ho of present interest to quantum information.