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Publication Citation: Ratio of the Al+ and Hg+ Optical Clock Frequencies to 17 Decimal Places

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Author(s): Wayne M. Itano; Till P. Rosenband; David Hume; P.O. Schmidt; Chin-Wen Chou; A. Brusch; Luca Lorini; Windell Oskay; Robert E. Drullinger; Sarah Bickman; Tara M. Fortier; Jason Stalnaker; Scott A. Diddams; William C. Swann; Nathan R. Newbury; David J. Wineland; James C. Bergquist;
Title: Ratio of the Al+ and Hg+ Optical Clock Frequencies to 17 Decimal Places
Published: August 25, 2008
Abstract: Frequency standards (atomic clocks) based on narrow optical transitions in 27Al+ and 199Hg+ have been developed over the past several years at NIST. These two types of standards are both based on single ions confined in Paul traps, but differ in the methods used to prepare and detect the internal atomic states. Al+ lacks a strong, laser-accessible transition for laser-cooling and for state preparation and detection. Coupling with a Be+ ion, trapped simultaneously with the Al+ ion, enables state manipulation, detection, and cooling of the Al+ ion. Both standards have achieved absolute reproducibilities of a few parts in 1017. Development of femtosecond laser frequency combs makes it possible to directly compare optical frequencies. The present determination of fAl/fHg is 1.052 871 833 148 990 438 (55), where the uncertainty is expressed in units of the least significant digit. Measurements of fAl/fHg made over about one year show a drift rate consistent with zero. This result can be used to place limits on time variations of fundamental constants such as the fine structure constant α.
Proceedings: Proc. 9th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology
Pages: pp. 307 - 312
Location: Tokyo, JP
Dates: August 25-28, 2008
Keywords: aluminum, atomic clocks,frequency standards,fundamental constants,ion traps,mercury,optical frequency standards
Research Areas: Physics, Atomic Physics
PDF version: PDF Document Click here to retrieve PDF version of paper (335KB)