scholarly journals Two-loop QED corrections in few-electron ions

2007 ◽  
Vol 85 (5) ◽  
pp. 521-529 ◽  
Author(s):  
V A Yerokhin ◽  
P Indelicato ◽  
V M Shabaev
Keyword(s):  
Excited States ◽  
Lamb Shift ◽  
Nuclear Charge ◽  
Detailed Comparison ◽  
Theoretical Uncertainty ◽  
Strength Parameter ◽  
Transition Energies ◽  
Energy Correction ◽  
Self Energy ◽  
Order Calculation

Results of a calculation valid to all orders in the nuclear-strength parameter Zα are presented for the two-loop Lamb shift, notably for the two-loop self-energy correction, for the ground and first excited states of ions with the nuclear charge numbers Z = 60–100. A detailed comparison of the all-order calculation with earlier investigations based on an expansion in the parameter Zα is given. The calculation removes the largest theoretical uncertainty for the 2pj–2s transition energies in heavy Li-like ions and is important for interpretation of experimental data.PACS Nos.: 31.30.Jv, 31.30.–i, 31.10.+z

Modification of HAM/3 excitation energies for ΠΠ* transitions of linear molecules

1980 ◽  
Vol 58 (16) ◽  
pp. 1687-1690 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Excitation Energy ◽  
Explicit Expression ◽  
Excited States ◽  
Configuration Interaction ◽  
Excitation Energies ◽  
Carbon Suboxide ◽  
Numerical Examples ◽  
Energy Correction ◽  
Linear Molecules ◽  
Configuration Interaction Calculations

The excitation energies calculated by the HAM/3 procedure for ΠΠ* transitions in linear molecules can be internally inconsistent by as much as ± 0.6 eV. In the recent study by Åsbrink etal., the problem was avoided by adopting Recknagel's expressions and requiring the proper average ΠΠ* excitation energy. In this paper, we trace the small inconsistency back to its origin in HAM/3 theory and derive the analytical expression for the energy correction as well as Recknagel's formulas. Numerical examples studied include all seven linear molecules investigated by Åsbrink etal. The explicit expression for the correction enables us to perform meaningful configuration-interaction calculations on the excited states, as illustrated by the carbon suboxide molecule.

scholarly journals Quantum electrodynamics with self-conjugated equations with spinor wave functions for fermion fields

2021 ◽  
pp. 2150086
Author(s):  
V. P. Neznamov ◽  
V. E. Shemarulin
Keyword(s):  
Cross Sections ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Quantum Electrodynamics ◽  
Lamb Shift ◽  
Wave Functions ◽  
Self Energy ◽  
Fermion Fields ◽  
Spinor Wave

Quantum electrodynamics (QED) with self-conjugated equations with spinor wave functions for fermion fields is considered. In the low order of the perturbation theory, matrix elements of some of QED physical processes are calculated. The final results coincide with cross-sections calculated in the standard QED. The self-energy of an electron and amplitudes of processes associated with determination of the anomalous magnetic moment of an electron and Lamb shift are calculated. These results agree with the results in the standard QED. Distinctive feature of the developed theory is the fact that only states with positive energies are present in the intermediate virtual states in the calculations of the electron self-energy, anomalous magnetic moment of an electron and Lamb shift. Besides, in equations, masses of particles and antiparticles have the opposite signs.

On excited states of the Au3 cluster: an ab initio study

Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Alexander Rusakov ◽  
André Zaitsevskii
Keyword(s):  
Excited States ◽  
Spectroscopic Data ◽  
Reasonable Agreement ◽  
Dipole Moments ◽  
Electronic States ◽  
Ab Initio Study ◽  
Many Body ◽  
Transition Energies ◽  
Vertical Transition ◽  
Theoretical Results

AbstractExcited electronic states of the Au3 cluster are studied within the shape-consistent small-core relativistic pseudopotential model using many-body multipartitioning perturbation theory. Vertical transition energies and dipole moments are evaluated. For highly symmetric isomer, these theoretical results are in reasonable agreement with spectroscopic data from experiments.

scholarly journals Relative Entropy as a Measure of Difference between Hermitian and Non-Hermitian Systems

Entropy ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 809
Author(s):  
Kabgyun Jeong ◽  
Kyu-Won Park ◽  
Jaewan Kim
Keyword(s):  
Relative Entropy ◽  
Lamb Shift ◽  
Strong Interactions ◽  
Average Value ◽  
Optical Microcavities ◽  
Self Energy ◽  
The Difference

We employ the relative entropy as a measure to quantify the difference of eigenmodes between Hermitian and non-Hermitian systems in elliptic optical microcavities. We have found that the average value of the relative entropy in the range of the collective Lamb shift is large, while that in the range of self-energy is small. Furthermore, the weak and strong interactions in the non-Hermitian system exhibit rather different behaviors in terms of the relative entropy, and thus it displays an obvious exchange of eigenmodes in the elliptic microcavity.

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