Lamb shifts

Noun

Lamb shift (plural Lamb shifts)

1. (quantum mechanics, quantum electrodynamics) A small difference between the energy levels 2S_½ and 2P_½ of the hydrogen atom, not predicted by the Dirac equation, whose detection in the Lamb–Retherford experiment of 1947 foreshadowed the development of quantum electrodynamics (in which the discrepancy is explained to be an effect of the emission and re-absorption of virtual photons); such a difference between otherwise expectedly equal energy levels of hydrogen or any other type of atom.
   • In recent years, a significant progress has been achieved in accurate measurements of the energy levels in heavy few-electron HCI including the 1s Lamb shift in H-like uranium [3.73-75], the hyperfine structure of H-like bismuth [3.69] and the ground state energies of He-like ions [3.29,20].1997, Heinrich F. Beyer, Heinz-Jürgen Kluge, Viatcheslav P. Shevelko, X-Ray Radiation of Highly Charged Ions, Springer, page 75