-
Chapter
Unifying Quantum Electro-Dynamics and Many-Body Perturbation Theory
Very accurate calculations have been performed on highly-charged helium like ions, using second-order QED (one- and two-photon exchange) or many-body perturbation technique (MBPT) with separately added first-o...
-
Chapter
Combination of many-body perturbation theory and quantum electrodynamics
A procedure for energy-dependent perturbation expansion has been developed, based upon the covariant evolution operator method. This makes it possible to treat energy-dependent perturbations very much like the...
-
Article
Combination of many-body perturbation theory and quantum electrodynamics
A procedure for energy-dependent perturbation expansion has been developed, based upon the covariant evolution operator method. This makes it possible to treat energy-dependent perturbations very much like th...
-
Chapter
Combining Quantum Electrodynamics and Electron Correlation
There is presently a large interest in studying highly charged ions in order to investigate the effects of quantum-electrodynamics (QED) at very strong fields. Such experiments can be performed at large accele...
-
Chapter
QED Calculations on Highly Charged Ions, Using a Unified MBPT-QED Approach
There is presently a great interest in studying QED effects in highly charged ions by means of large accelerators, and the best information is usually gained from the study of multi-electron ions. It might the...
-
Chapter
Coupled Clusters and Quantum Electrodynamics
We start by reviewing, as a background, the standard non-relativistic and relativistic many-body perturbative and coupled-cluster approaches in the way we have implemented them. The covariant-evolution-operato...
-
Chapter
Relativistically Covariant Many-Body Perturbation Procedure
A covariant evolution operator (CEO) can be constructed, representing the time evolution of the relativistic wave unction or state vector. Like the nonrelativistic version, it contains (quasi-)singularities. T...
-
Article
Two photon QED corrections in helium like highly charged ions
An overview of calculations and measurements of the energy levels of helium-like ions is presented. We focus on the two-photon QED effects, and conclude that measurements of the excited states of large Z helium-l...
-
Chapter and Conference Paper
Few-Body Problems in Atomic Physics
By means of new experimental techniques heavy ions with a few electrons can now be studied with improved accuracy. In combination with new computational schemes such data can be used for testing QED at strong ...
-
Article
Ab-initio calculations of pair-correlation effects on the hyperfine structure of the 4s 4p and 4s 3d configurations of Ca
The hyperfine structure of the 4s 4p and 4s 3d configurations of Ca has been evaluated using many-body perturbation theory. Single excitations and pair-correlation effects have been included by solving coupled on...
-
Article
Analysis of the hyperfine structure of the 4s 4p configuration in Ca and the nuclear quadrupole moment of43Ca
Hyperfine structure 〈r −3〉 integrals are calculated for the 4s 4p configuration in Ca, including the effects of core polarization. This is done with the use of LS-dependent Hartree-Fock orbitals. The calculated e...
