Relativistic and QED Effects in Highly Charged Ions

QED can be considered to be one of the most precisely tested theories in physics at present. It provides an extremely accurate description of systems such as hydrogen and helium atoms, as well as for bound-leptonic systems, for example, positronium and muonium. Remarkable agreement between theory and experiment has been achieved with respect to the determination of the hyperfine structure and the Lamb shift. The same holds true for the electronic and muonic g-factors. The free-electron g-factor is determined at present as 

The field strength at the nuclear surface may be even higher. For example, at the surface of a uranium nucleus it amounts to about E = 2 x 1019 V cm-1. 

An even higher precision is achieved in experiments with highly charged lithiumlike ions. The splitting between 2pi/2 and 2s levels in lithium-like uranium was determined experimentally (Schweppe et al. 1991) to be 280.59 eV with an uncertainty of only 0.09 eV. To a large extent, this result has initiated calculations of QED 

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