RELATIVISTIC MANY-BODY AND QED CALCULATIONS ON ATOMIC SYSTEMS

摘要

A review is given of many-body perturbation methods, particularly in the all-order and coupled-cluster forms. Relativistic many-body schemes are analyzed in terms of one- and two-photon potentials, derived by means of QED. A complete second-order (nonradiative) calculation for He-like ions is presented, including repeated Breit interactions as well as the effects of retardation and of negative-energy states, but omitting the Lamb shift. Numerical results of some Lamb-shift calculations are also given. From the analysis, conclusions can be drawn concerning the accuracy of certain relativistic many-body approaches. (C) 1996 John Wiley & Sons, Inc. [References: 89]