L. Labzowsky

Nuclear polarization effects in spectra of multicharged ions

Abstract We evaluate the nuclear-polarization energy shifts for one-electron 208 82 Pb and 238 92 U ions. In contrast to previous calculations, the effect of nuclear polarizability is found to be essentially of minor significance for high-precision measurements of the Lamb shift in heavy multicharged ions. The calculations are carried out employing different numerical methods. We also provide a comparison of our numerical results with analytical estimates.

Second order loop after loop self-energy correction for few-electron multicharged ions

Abstract One of the self-energy corrections of second order in α = e 2 h c is calculated for 1 s 1 2 , 2s 1 2 and 2p 1 2 states. The calculations involve the triple summation over the Dirac spectrum that was performed by the numerical method of the space discretization. This was achieved by the rearrangement of the summations in such a way that two of them were included in the corrections to the wave functions.

QED calculation of E1M1 and E1E2 transition probabilities in one-electron ions with arbitrary nuclear charge

The quantum electrodynamical theory of the two-photon transitions in hydrogenlike ions is presented. The emission probability for 2s1/2 → 2γ(E1) + 1s1/2 transitions is calculated and compared to the results of the previous calculations. The emission probabilities 2p1/2 → γ(E1) + γ(E2) + 1s1/2 and 2p1/2 → γ(E1) + γ(M1) + 1s1/2 are also calculated for the nuclear charge Z values 1 ≤ Z ≤ 100. This is the first calculation of the two latter probabilities. The results are given in two different gauges.

Higher-order QED corrections for multi-charged ions

The higher-order QED corrections for one- and two-electron heavy ions are analysed. The different methods of renormalization are discussed: the traditional potential-expansion method and the new one, based on the direct numerical subtraction of divergencies. The extraction of the reference state from the sums over the intermediate states in higher-order corrections is considered. It is shown, that this extraction leads to some special corrections to the energy. The Low theory of the line profile is used for the calculation of the higher-order QED corrections and the nonresonant corrections distorting the Lorentz line profile are also discussed.

Parity violation in heliumlike uranium

Abstract Parity violation effects in radiation spectra of He-like uranium 235 U 90+ are considered. The degree of photon circular polarization P is calculated. The value of P is of the order of 10 -4 .

Testing the time dependence of fundamental constants in the spectra of multicharged ions

A new method for measuring a possible time dependence of the fine-structure constant (

Chapter 8 - QED theory of atoms

\alpha

Multiple commutator expansion for the Lamb shift in a strong Coulomb field

) is proposed. The method is based on the level-crossing in two-electron highly-charged ions facilitating resonance laser measurements of the distance between the levels at the point of crossing. This provides an enhancement factor of about

Nonresonant corrections to the 1 s − 2 s two-photon resonance for the hydrogen atom

10^{3}

Influence of external electric fields on multi-photon transitions between the 2s, 2p and 1s levels for hydrogen and antihydrogen atoms and hydrogen-like ions

in Helium-like Europium and thus reduces the requirements for the relative accuracy of resonance laser measurements at about