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Displaying 26 - 50 of 220

Frequency ratio of Al + and Hg + single-ion optical clocks; metrology at the 17th decimal place

March 6, 2008
Author(s)
Till P. Rosenband, David Hume, P. O. Schmidt, Chin-Wen Chou, Anders Brusch, Luca Lorini, Windell Oskay, Robert E. Drullinger, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Nathan R. Newbury, W Swann, Wayne M. Itano, David J. Wineland, James C. Bergquist
We report the frequency ratio of the two most accurate and stable atomic clocks with a total fractional uncertainty of 5.2 X 10 -17 . This frequency ratio is the best-known physical constant that is not a simple integer. Repeated measurements during the

Optical-to-microwave frequency comparison with fractional uncertainty of 10 -15

October 1, 2007
Author(s)
Jason Stalnaker, Scott A. Diddams, Tara M. Fortier, K Kim, Leo W. Hollberg, James C. Bergquist, Wayne M. Itano, Marie Delaney, Luca Lorini, Windell Oskay, Thomas P. Heavner, Steven R. Jefferts, Filippo Levi, Thomas E. Parker, Jon H. Shirley
We report the technical aspects of the optical-to-microwave comparison for our recent measurements of the optical frequency of the mercury single-ion frequency standard in terms of the SI second as realized by the NIST-F1 cesium fountain clock. Over the

Optical frequency standards based on mercury and aluminum ions

September 12, 2007
Author(s)
Wayne M. Itano, James C. Bergquist, Anders Brusch, Scott A. Diddams, Tara M. Fortier, Thomas P. Heavner, Leo W. Hollberg, David Hume, Steven R. Jefferts, Luca Lorini, Thomas E. Parker, Till P. Rosenband, Jason Stalnaker
Single-trapped-ion frequency standards based on a 282 nm transition in 199Hg+ and on a 267 nm transition in 27Al+ have been developed at NIST over the past several years. Their frequencies are measured relative to each other and to the NIST primary

Frequency Comparison of Al + and Hg + Optical Standards

June 24, 2007
Author(s)
Till P. Rosenband, David Hume, Anders Brusch, Luca Lorini, P. O. Schmidt, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Nathan R. Newbury, W Swann, Windell Oskay, Wayne M. Itano, David J. Wineland, James C. Bergquist
We compare the frequencies of two single ion frequency standards: 27Al + and 199Hg +. Systematic fractional frequency uncertainties of both standards are below 10 -16, and the statistical measurement uncertainty is below 5 x 10 -17. Recent ratio

Observation of the 1 S 0 - 3 P 0 clock transition in 27 Al +

June 1, 2007
Author(s)
Till P. Rosenband, P. O. Schmidt, David Hume, Wayne M. Itano, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Jeroen Koelemeij, James C. Bergquist, David J. Wineland
We report for the first time, laser spectroscopy of the 1S 0 – 3P 0 clock transition in 27Al +. A single aluminum ion and a single beryllium ion are simultaneously confined in a linear Paul trap, coupled by their mutual Coulomb repulsion. This coupling

Improved Limits on Variation of the Fine Structure Constant and Violation of Local Position Invariance

May 29, 2007
Author(s)
Tara M. Fortier, Neil Ashby, James C. Bergquist, Marie Delaney, Scott A. Diddams, Thomas P. Heavner, Leo W. Hollberg, Wayne M. Itano, Steven R. Jefferts, K Kim, Windell Oskay, Thomas E. Parker, Jon H. Shirley, Jason Stalnaker, Filippo Levi, Luca Lorini
We report tests of Local Position Invariance (LPI) and constancy of fundamental constants from measurements of the frequency ratio of the 282-nm 199Hg + optical clock transition to the ground-state hyperfine splitting in 133Cs. Analysis of the frequency

Absolute frequency measurement of the neutral 40 Ca optical frequency standard at 657 nm based on microkelvin atoms

March 14, 2007
Author(s)
G Wilpers, Christopher W. Oates, Scott A. Diddams, A Bartels, Tara M. Fortier, Windell Oskay, James C. Bergquist, Steven R. Jefferts, Thomas P. Heavner, Thomas E. Parker, Leo W. Hollberg
We report an absolute frequency measurement of the optical clock transition at 657 nm in 40Ca with a relative uncertainty of 7.5x10 -15, the most accurate frequency measurement of a neutral atom optical transition to date. Relative instabilities of 2x10

Precision Atomic Spectroscopy for Improved Limits on Variation of the Fine Structure Constant and Local Position Invariance

February 16, 2007
Author(s)
Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Neil Ashby, Luca Lorini, Windell Oskay, Marie Delaney, James C. Bergquist, Steven R. Jefferts, Thomas E. Parker, Thomas P. Heavner, Filippo Levi, Jon H. Shirley, Wayne M. Itano, Kyoungsik Kim, Leo W. Hollberg
We report tests of local position invariance (LPI) and the constancy of fundamental constants from measurements of the frequency ratio of the 282-nm $^{199}$Hg$^+$ optical clock transition to the ground state hyperfine splitting in $^{133}$Cs. Analysis of

Trapped atomic ions and quantum information processing

July 16, 2006
Author(s)
David J. Wineland, Dietrich G. Leibfried, James C. Bergquist, Brad R. Blakestad, John J. Bollinger, Joseph W. Britton, J Chiaverini, Ryan Epstein, David Hume, Wayne M. Itano, John D. Jost, Emanuel H. Knill, Jeroen Koelemeij, C. Langer, R Ozeri, Rainer Reichle, Till P. Rosenband, Tobias Schaetz, Piet Schmidt, Signe Seidelin, Nobuyasu Shiga, Janus Wesenberg
The basic requirements for quantum computing and quantum simulation (Single- and multi-qubit gates, long memor times, etc.)have been demonstrated in separate experiments on trapped ions. Construction of a large-scale information processor will require

A single-atom optical clock with high accuracy

July 14, 2006
Author(s)
Windell Oskay, Scott A. Diddams, Elizabeth A. Donley, Tara M. Fortier, Thomas P. Heavner, Leo W. Hollberg, Wayne M. Itano, Steven R. Jefferts, M J. Jensen, Kyoungsik Kim, F Levi, Thomas E. Parker, James C. Bergquist
For the past fifty years, atomic frequency standards based on the cesium ground-state hyperfine splitting have been the most accurate timepieces in the world. One of the most accurate, current-generation, cesium standards is the NIST-F1 fountain, which has

Spectroscopy of atomic and molecular ions using quantum logic

June 25, 2006
Author(s)
Piet Schmidt, Till P. Rosenband, Jeroen Koelemeij, David Hume, Wayne M. Itano, James C. Bergquist, David J. Wineland
Recently developed techniques for quantum computation using trapped ions allow unprecedented coherent control of the internal and external states of single atoms. Here we report how these techniques can be employed to perform precision spectroscopy of