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

Published

August 25, 2008

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

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 f_Al/f_Hg is 1.052 871 833 148 990 438 (55), where the uncertainty is expressed in units of the least significant digit. Measurements of f_Al/f_Hg 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 Title

Proc. 9th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology

Conference Dates

August 25-28, 2008

Conference Location

Tokyo, JP

Pub Type

Conferences

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Keywords

aluminum, atomic clocks, frequency standards, fundamental constants, ion traps, mercury, optical frequency standards

Citation

Itano, W. , Rosenband, T. , Hume, D. , Schmidt, P. , Chou, C. , Brusch, A. , Lorini, L. , Oskay, W. , Drullinger, R. , Bickman, S. , Fortier, T. , Stalnaker, J. , Diddams, S. , Swann, W. , Newbury, N. , Wineland, D. and Bergquist, J. (2008), Ratio of the Al⁺ and Hg⁺ Optical Clock Frequencies to 17 Decimal Places, Proc. 9th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, Tokyo, JP, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=842568 (Accessed January 2, 2025)