Improved Lamb-Shift Calculation for All Values ofZ

Abstract

A previous covariant evaluation of the Lamb shift for small atomic numbers $Z$ is extended to be valid for large $Z$ and agrees with independent numerical evaluations for $Z$ near 80. The results improve the precision tests of quantum electrodynamics and could be used for one-electron atoms with any $Z$, x rays at large $Z$, and superheavy elements with $Z\alpha >1\mathrm{}$. A substantially new value (due to deuteron size) is found for the deuterium Lamb shift: 1059.27 ± 0.03 MHz.