Thursday, December 01, 2005

Two-loop Lamb shift in U^{89+}

Researchers at Lawrence Livermore National Laboratory have used U^{89+} ions (that's Uranium stripped of all but three electrons) to measure the two-loop Lamb shift in Lithium-like ions at large Z, providing one of the most stringent tests of QED in strong fields so far. There are no theoretical predictions for Lithium-like ions, but when extrapolated to the Hydrogen-like case of U^{91+}, their results are in excellent agreement with theoretical predictions. It is always nice to see experiment agree with theory.