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Published Online February 14, 2008
Science DOI: 10.1126/science.1153341

Reports

Submitted on November 26, 2007
Accepted on January 23, 2008

Sr Lattice Clock at 1 x 10–16 Fractional Uncertainty by Remote Optical Evaluation with a Ca Clock

A. D. Ludlow 1, T. Zelevinsky 1, G. K. Campbell 1, S. Blatt 1, M. M. Boyd 1, M. H. G. de Miranda 1, M. J. Martin 1, J. W. Thomsen 1, S. M. Foreman 1, Jun Ye 1*, T. M. Fortier 2, J. E. Stalnaker 2, S. A. Diddams 2, Y. Le Coq 2, Z. W. Barber 2, N. Poli 2, N. D. Lemke 2, K. M. Beck 2, C. W. Oates 2

1 JILA, National Institute of Standards and Technology, and University of Colorado, Department of Physics, University of Colorado, Boulder, CO 80309–0440, USA.
2 National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.

* To whom correspondence should be addressed.
Jun Ye , E-mail: ye{at}jila.colorado.edu

Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between them. We have realized a high-performance remote comparison of optical clocks over kilometer-scale urban distances, a key step for development, dissemination, and application of these optical standards. Through this remote comparison and a proper design of lattice-confined neutral atoms for clock operation, we evaluate the uncertainty of a strontium (Sr) optical lattice clock at the 1 x 10–16 fractional level, surpassing the best current evaluations of cesium (Cs) primary standards. We also report on the observation of density-dependent effects in the spin-polarized fermionic sample and discuss the current limiting effect of blackbody radiation-induced frequency shifts.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Quantum State Engineering and Precision Metrology Using State-Insensitive Light Traps.
J. Ye, H. J. Kimble, and H. Katori (2008)
Science 320, 1734-1738
   Abstract »    Full Text »    PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)