Recent atomic clock comparisions at NIST

Published

October 1, 2008

Author(s)

Luca Lorini, Neil Ashby, Anders Brusch, Scott Diddams, Robert E. Drullinger, Eric Eason, Tara Fortier, Pat Hastings, Thomas P. Heavner, David Hume, Wayne M. Itano, Steven R. Jefferts, Nathan R. Newbury, Tom Parker, Till P. Rosenband, Jason Stalnaker, William C. Swann, David J. Wineland, James C. Bergquist

Abstract

The record of atomic clock frequency comparisons at NIST over the past half-decade provides one of the tightest constraints of any present-day, temporal variations of the fundamental constants. Notably, the 6-year record of increasingly precise measurements of the absolute frequency of the Hg⁺ single-ion optical clock (using the cesium primary frequency standard NIST-F1) constrains the temporal variation of the fine structure constant α to less than 2 &#8226 10^-16yr^-1 and offers Local Position Invariance test in the framework of General Relativity. The most recent measurement of the frequency ratio of the Al⁺ and Hg⁺ optical clocks is reported with a fractional frequency uncertainty of (5.2 &#8226 10^-17). The record of such measurements over the last year sensitively tests for a temporal variation of α and constraints (α/α = (–1.6 ± 2.3) &#8226 10^-17yr^-1), consistent with zero.

Citation

European Journal of Physics

Volume

163

Pub Type

Journals

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Keywords

atom trapping and cooling, quantum computation:quantum information processing, quantum superpositions, quantum-state engineering, trapped ions

Citation

Lorini, L. , Ashby, N. , Brusch, A. , Diddams, S. , Drullinger, R. , Eason, E. , Fortier, T. , Hastings, P. , Heavner, T. , Hume, D. , Itano, W. , Jefferts, S. , Newbury, N. , Parker, T. , Rosenband, T. , Stalnaker, J. , Swann, W. , Wineland, D. and Bergquist, J. (2008), Recent atomic clock comparisions at NIST, European Journal of Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=842476 (Accessed October 21, 2025)