One-loop self-energy correction in a strong binding field

A new scheme for the numerical evaluation of the one-loop self-energy correction to all orders in Z \alpha is presented. The scheme proposed inherits the attractive features of the standard potential-expansion method but yields a partial-wave expansion that converges more rapidly than in the other methods reported in the literature.Comment: 8 pages, 4 table

QED calculation of the 2p3/2-2p1/2 transition energy in five-electron ion of argon

We perform ab initio QED calculation of the (1s)^2(2s)^22p_{3/2} - (1s)^2(2s)^22p_{1/2} transition energy in the five-electron ion of argon. The calculation is carried out by perturbation theory starting with an effective screening potential approximation. Four different types of the screening potentials are considered. The rigorous QED calculations of the two lowest-order QED and electron-correlation effects are combined with approximate evaluations of the third- and higher-order electron-correlation contributions. The theoretical value for the wavelength obtained amounts to 441.261(70) (nm, air) and perfectly agrees with the experimental one, 441.2559(1) (nm, air).Comment: 10 pages, 3 figures, 1 tabl

Evidence for the absence of regularization corrections to the partial-wave renormalization procedure in one-loop self energy calculations in external fields

The equivalence of the covariant renormalization and the partial-wave renormaliz ation (PWR) approach is proven explicitly for the one-loop self-energy correction (SE) of a bound electron state in the presence of external perturbation potentials. No spurious correctio n terms to the noncovariant PWR scheme are generated for Coulomb-type screening potentia ls and for external magnetic fields. It is shown that in numerical calculations of the SE with Coulombic perturbation potential spurious terms result from an improper treatment of the unphysical high-energy contribution. A method for performing the PWR utilizing the relativistic B-spline approach for the construction of the Dirac spectrum in external magnetic fields is proposed. This method is applied for calculating QED corrections to the bound-electron $g$-factor in H-like ions. Within the level of accuracy of about 0.1% no spurious terms are generated in numerical calculations of the SE in magnetic fields.Comment: 22 pages, LaTeX, 1 figur

One-loop self-energy correction to the 1s and 2s hyperfine splitting in H-like systems

The one-loop self-energy correction to the hyperfine splitting of the 1s and 2s levels in H-like low-Z atoms is evaluated to all orders in Z\alpha. The results are compared to perturbative calculations. The residual higher-order contribution is evaluated. Implications to the specific difference of the hyperfine structure intervals 8\Delta \nu_2 - \Delta \nu_1 in He^+ are investigated.Comment: 17 pages, RevTeX, 3 figure

Evaluation of the low-lying energy levels of two- and three-electron configurations for multi-charged ions

Accurate QED evaluations of the one- and two-photon interelectron interaction for low lying two- and three-electron configurations for ions with nuclear charge numbers $60\le Z \le 93$ are performed. The three-photon interaction is also partly taken into account. The Coulomb gauge is employed. The results are compared with available experimental data and with different calculations. A detailed investigation of the behaviour of the energy levels of the configurations $1s_{1/2}2s_{1/2} {}^1 S_0$, $1s_{1/2}2p_{1/2} {}^3 P_0$ near the crossing points Z=64 and Z=92 is carried out. The crossing points are important for the future experimental search for parity nonconserving (PNC) effects in highly charged ions