Quantum electrodynamics of strong fields: Status and perspectives

We report on the current status of Lamb shift contributions in hydrogenlike heavy ions which have to be calculated non-perturbatively in Zα. 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 209Bi, where again fair agreement between the quantum electrodynamical calculations and the experiment is found. © 1998 Academic Press Inc.