Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Blackbody radiation shift of the 27Al+ 1S0 - 3P0 transition



Till P. Rosenband, Wayne M. Itano, Piet Schmidt, David Hume, Jeroen Koelemeij, James C. Bergquist, David J. Wineland


The differential polarizability, due to near-infrared light at 1126 nm, of the 27Al+1S03P0 transition is measured to be {Δ}α = (1.6 ± x 10-31 m3, where {Δ}α = αP - αS is the difference between the excited and ground state polarizabilities. This measurement is combined with expeimental oscillator strengths to extrapolate the differential static polarizability of the clock transition as {Δ}α(0) = 4πε0 x (1.5 ± 0.5) x 10-31m3. The resulting room temperature blackbody shift of {Δ}Ņ / Ņ = -8(3)x1018 is the lowest known shift of all atomic transistions under consideration for optical frequency standards. A method is presented to estimate the differntial static polarizability of an optical transition, from a differential Stark shift measurement.
Proceedings Title
Proc. EFTF Conf.
Conference Dates
March 27-30, 2006
Conference Location


aluminum ion clock, atomic polarizability, blackbody shift
Created March 27, 2006, Updated January 27, 2020