Lamb shift calculation

The experimental results in the first five lines in Table 12.3 seem to be compatible with the theoretical value in (12.11). This compatibility crucially depends on the value of the proton charge radius [27]. We presented in Table 12.3 also theoretical values of the IS Lamb shift calculated with the once popular earlier lower values of the radius, and they are clearly incompatible with the experimental data on the IS Lamb shift. However, it is necessary to remember that the experimental results in the first five lines in the Table are biased , namely they depend on the experimental value of the 2Si/2 — Pil2 Lamb shift [15, 24, 25]. In view of a rather large scattering of the results for the classic Lamb shift such dependence is unwelcome. 

The uncertainty of theoretical calculations including the estimation of missing or uncalculated terms has been receiving increasing scrutiny as techniques have advanced. One of the most recent two-electron Lamb shift calculations by Persson et al. [9] estimates missing correlation effects in QED contributions at 0.1 eV for all elements or 20 ppm of transition energies in medium Z ions. In earlier work, Drake [4] claimed uncertainty for Z = 23 was < 0.005 eV or 1 ppm of helium-like resonance lines due to uncalculated higher order terms. Some of the latest theoretical calculations for the w transition in medium Z ions are summarized in Table 3. 

Lamb-shift calculations for highly charged ions... 

Self energy and vacuum polarization of order a and the nuclear size account for the measured Lamb shift in hydrogenlike heavy ions at the current level of accuracy. Radiative corrections of the order contribute to the Lamb shift of the lsi/2 state and amount to about 1 eV for uranium. Facing higher precision in experiments, these corrections have to be evaluated to yield a reliable Lamb shift calculation. 

The status of the lsi/2 Lamb shift calculations in hydrogenlike atoms... 

In the preceeding sections we have shown the current status of quantum electrodynamical and related calculations in heavy hydrogenlike systems with its unique strong electric and magnetic fields. From our present experimental knowledge there is no contradiction to the theory of quantum electrodynamics as we use it nowadays. However, an increasing experimental precision may still point to deviations in the theory since in Lamb shift calculations the predictions are still at least one order of magnitude more precise than the best experimental values. On the other hand we... 

J. Seke, Complete lamb-shift calculation to order by applying the methods of non-relativistic quantum electrodynamics, Nuovo Cimento D 18 (1996) 533. 

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