T. Beier

RECOIL CORRECTION TO THE GROUND-STATE ENERGY OF HYDROGENLIKE ATOMS

The recoil correction to the ground state energy of hydrogenlike atoms is calculated to all orders in \alpha Z in the range Z = 1-110. The nuclear size corrections to the recoil effect are partially taken into account. In the case of hydrogen, the relativistic recoil correction beyond the Salpeter contribution and the nonrelativistic nuclear size correction to the recoil effect, amounts to -7.2(2) kHz. The total recoil correction to the ground state energy in hydrogenlike uranium (^{238}U^{91+}) constitutes 0.46 eV.

Current status of Lamb shift predictions for heavy hydrogen-like ions

Abstract A summary of the various contributions to the Lamb shift of 1 S 1 2 , 2 S 1 2 , and 2 P 1 2 states in hydrogen-like 197 79 Au, 208 82 Pb, 232 90 Th, and 238 92 U is given. Uncertainties due to uncalculated two-photon self-energy diagrams and insufficiently known nuclear parameters are estimated.

Two-loop ladder diagram for the vacuum polarization contribution in hydrogen-like ions

We discuss a calculation scheme for the two-loop ladder graph vacuum polarization contribution to the Lamb shift in hydrogen-like heavy ions. It is obtained by including the vacuum polarization potential self-consistently into the Dirac equation. Numerical values are presented for all systems with nuclear charge numbers . Possible limitations of our method are mentioned. In addition, we also present numerical values for the Wichmann - Kroll contribution to the Lamb shift for all hydrogen-like systems utilizing an extended nuclear charge distribution in the Z-range 30 - 100.

Determination of the electron’s mass from g-factor experiments on 12C5+ and 16O7+

Abstract We present a derivation of the electron’s mass from our experiment on the electronic g factor in 12C5+ and 16O7+ together with the most recent quantum electrodynamical predictions. The value obtained from 12C5+ is me=0.0005485799093(3) u, that from oxygen is me=0.0005485799092(5) u. Both values agree with the currently accepted one within 1.5 standard deviations but are four respectively two-and-a-half times more precise. The contributions to the uncertainties of our values and perspectives for the determination of the fine-structure constant α by an experiment on the bound-electron g factor are discussed.

Relativistic recoil correction to hydrogen energy levels

The relativistic recoil correction to hydrogen energy levels is calculated to all orders in for the point nucleus. Previously published values have been improved in accuracy. It is found that the recoil correction, beyond the Salpeter one, amounts to and for the 1s and 2s states, respectively. The corresponding contribution to the 2s - Lamb shift constitutes .

Quantum Electrodynamics of Strong Fields: Status and Perspectives‡

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

The magnetic moment anomaly of the electron bound in hydrogen-like oxygen 16O7+

The measurement of the g-factor of the electron bound in a hydrogen-like ion is a high-accuracy test of the theory of quantum electrodynamics (QED) in strong fields. Here we report on the measurement of the g-factor of the bound electron in hydrogen-like oxygen (16O7+). In our experiment a single highly charged ion is stored in a Penning trap. The electronic spin state of the ion is monitored via the continuous Stern?Gerlach effect in a quantum non-demolition measurement. Quantum jumps between the two spin states (spin up and spin down) are induced by a microwave field at the spin precession frequency of the bound electron. The g-factor of the bound electron is obtained by varying the microwave frequency and counting the number of spin flips. The comparison of our experimental values for the g-factor of the bound electron with the theoretical values shows excellent agreement and confirms the recent non-perturbative QED calculations.

Direct evaluation of the two-electron self-energy corrections to the ground state energy of lithium-like ions

We present a calculation of the two-electron self-energy corrections to the ground state energy of Li-like ions in the range Z = 20-100. The calculation is performed both for point and extended nuclei to all orders in .

Enhanced role of electron correlation in the hyperfine interactions in 2D5/2 states in alkaline-earth-metal ions

The low-lying n(=3,4,5)d

New value for the electron's mass?theoretical foundations

^2D_{5/2}