We calculate the one- and two-loop corrections of order α(Zα)6 and α2(Zα)6, respectively, to the Lamb shift in hydrogenlike systems using the formalism of nonrelativistic quantum electrodynamics. We obtain general results valid for all hydrogenic states with nonvanishing orbital angular momentum and for the normalized difference of S states. These results involve the expectation value of local effective operators and relativistic corrections to Bethe logarithms. The one-loop correction is in agreement with previous calculations for the particular cases of S, P, and D states. The two-loop correction in the order α2(Zα)6 includes the pure two-loop self-energy and all diagrams with closed fermion loops. The obtained results allow one to obtain improved theoretical predictions for all excited hydrogenic states.
U. D. Jentschura et al., "Nonrelativistic QED Approach to the Lamb Shift," Physical Review A - Atomic, Molecular, and Optical Physics, vol. 72, no. 6, pp. 062102-1-062102-20, American Physical Society (APS), Dec 2005.
The definitive version is available at https://doi.org/10.1103/PhysRevA.72.062102
Keywords and Phrases
Lamb Shift; Nonrelativistic QED Approach; One-loop Correction; S States; Fermions; Finite Difference Method; Mathematical Operators; Quantum Theory; Electrodynamics
International Standard Serial Number (ISSN)
Article - Journal
© 2005 American Physical Society (APS), All rights reserved.