Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Observation of the 1S0-3P0 clock transition in 27Al+



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 1S03P0 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 allows the beryllium ion to sympathetically cool the aluminum ion, and also enables transfer of the aluminum's electronic state to the beryllium's hyperfine state, which can be measured with high fidelity. These techniques are applied to a measurement of the clock transition frequency, Ņ = 1 121 015 393 207 851(8) Hz. They are also used to measure the lifetime fo the metastable clock state, τ = 20.6+/-1.4 s, the ground state 1S0 g factor, gs = -0.00079248(14), and the excited stated 3P0 g factor = -0.00197686(21) in units of Bohr magneton.
Physical Review Letters


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


Rosenband, T. , Schmidt, P. , Hume, D. , Itano, W. , Fortier, T. , Stalnaker, J. , Diddams, S. , Koelemeij, J. , Bergquist, J. and Wineland, D. (2007), Observation of the <sup>1</sup>S<sub>0</sub>-<sup>3</sup>P<sub>0</sub> clock transition in <sup>27</sup>Al<sup>+</sup>, Physical Review Letters, [online], (Accessed May 11, 2021)
Created June 1, 2007, Updated January 27, 2020