H. Persson

Second order loop after loop self-energy correction for few-electron multicharged ions

Abstract One of the self-energy corrections of second order in α = e 2 h c is calculated for 1 s 1 2 , 2s 1 2 and 2p 1 2 states. The calculations involve the triple summation over the Dirac spectrum that was performed by the numerical method of the space discretization. This was achieved by the rearrangement of the summations in such a way that two of them were included in the corrections to the wave functions.

Current status of Lamb shift predictions for heavy hydrogen-like ions

Abstract A summary of the various contributions to the Lamb shift of 1 S 1 2 , 2 S 1 2 , and 2 P 1 2 states in hydrogen-like 197 79 Au, 208 82 Pb, 232 90 Th, and 238 92 U is given. Uncertainties due to uncalculated two-photon self-energy diagrams and insufficiently known nuclear parameters are estimated.

Higher-order QED corrections for multi-charged ions

The higher-order QED corrections for one- and two-electron heavy ions are analysed. The different methods of renormalization are discussed: the traditional potential-expansion method and the new one, based on the direct numerical subtraction of divergencies. The extraction of the reference state from the sums over the intermediate states in higher-order corrections is considered. It is shown, that this extraction leads to some special corrections to the energy. The Low theory of the line profile is used for the calculation of the higher-order QED corrections and the nonresonant corrections distorting the Lorentz line profile are also discussed.

Quantum Electrodynamics of Strong Fields: Status and Perspectives‡

Abstract We report on the current status of Lamb shift contributions in hydrogenlike heavy ions which have to be calculated non-perturbatively in Z α. We subsequently outline the quantum electrodynamical corrections of first order in α, the effects resulting from nuclear mass and size, the quantum electrodynamical corrections of second order in α and the nuclear polarization effects. An excellent agreement with experimental data is found at the current level of precision but insufficient knowledge of nuclear parameters appears to be the major boundary to much more precise predictions. Additionally we also focus on the hyperfine splitting of the ground state in hydrogenlike 209 Bi, where again fair agreement between the quantum electrodynamical calculations and the experiment is found.

A theoretical survey of QED tests in highly charged ions

Recent progress in precision tests of QED in strong nuclear fields is presented and discussed. The discussion is focused on theoretical comparisons with experiment on the 1s Lamb-shift in H-like uranium, the two-electron Lamb-shift in He-like ions, the hyperfine structure of H-like bismuth and the bound-electron g-factor in H-like ions.

Adapting high Z methods for a \({\user1{g}_\user1{J} } \) factor prediction for C5+, S15+ and Ca19+

AbstractWe present a

INFLUENCE OF NUCLEAR SIZE ON QED CORRECTIONS IN HYDROGENLIKE HEAVY IONS

{\user1{g}_\user1{J} }

Many-body calculation of the 2[ital p][sub 1/2,3/2]-2[ital s][sub 1/2] transition energies in Li-like [sup 238]U

factor prediction for the ground state of C5+, S15+ and Ca19+. For this purpose we have developed a subtraction scheme within the QED calculations which is outlined in this contribution. Current theoretical limits are mentioned.