Quantum electrodynamic effects

Quantum electrodynamics effects (see [29] and section 2.3), arbitrary nuclear models, and correlation with IC shells [30] can be efficiently treated within GRECPs. 

When innermost core shells must be treated explicitly, the four-component versions of the GREGP operator can be used, in principle, together with the all-electron relativistic Hamiltonians. The GRECP can describe here some quantum electrodynamics effects (self-energy, vacuum polarization etc.) thus avoiding their direct treatment. One more remark is that the... 

The data of atomic spectroscopy are of extreme importance in revealing the nature of quantum-electrodynamical effects. For the investigation of many-electron atoms and ions, it is of great importance to combine theoretical and experimental methods. Therefore, the methods used must be universal and accurate. A number of physical characteristics of the many-electron atom (e.g., a complete set of quantum numbers) may be found only on the basis of theoretical considerations. In many cases the mathematical modelling of physical objects and processes using modern computers may successfully replace the corresponding experiments. In this book we shall describe the contemporary state of the theory of many-electron atoms and ions, the peculiarities of their structure and spectra as well as the processes of their interaction with radiation, and some applications. 

All the terms up to this point can be calculated to high precision, leaving a finite residual piece due to higher order relativistic and quantum electrodynamic effects which lie at the frontier of current theory. 

Aside from relativistic and quantum electrodynamic effects, a single molecule in free space is completely described by the Schrfidinger equation (8-2.1)... 

The theoretical energy levels are determined to high accuracy by the Dirac eigenvalue, quantum electrodynamic effects such as the self energy and vacuum polarization, finite-nuclear-size corrections, and nuclear motion effects. 

In this last section we mention a few cases, where properties other than the energy of a system are considered, which are influenced in particular by the change from the point-like nucleus case (PNC) to the finite nucleus case (FNC) for the nuclear model. Firstly, we consider the electron-nuclear contact term (Darwin term), and turn then to higher quantum electrodynamic effects. In both cases the nuclear charge density distribution p r) is involved. The next item, parity non-conservation due to neutral weak interaction between electrons and nuclei, involves the nuclear proton and neutron density distributions, i.e., the particle density ditributions n r) and n (r). Finally, higher nuclear electric multipole moments, which involve the charge density distribution p r) again, are mentioned briefly. 

The leading quantum electrodynamic effects to be accounted for in electronic structure calculations are the radiative corrections known as electron self-energy interaction and vacuum polarization. For the energy of electronic systems, the latter is usually small compared to the former, but only the latter can be expressed in terms of an effective additive potential to be included in the electronic structure calculations. The total vacuum polarization potential can be expanded into a double power series in the fine structure constant a and the external coupling constant Za. The lowest-order term, the Uehling potential, can be expressed as [110-112] ... 

In his work, Goldstone70 introduced the graphical techniques into many-body physics making use of Feynman-like diagrams. However, interactions were taken to be instantaneous and the effects of relativity were ignored. In recent years, the growing interest in the treatment of relativistic and quantum electrodynamic effects in atoms and molecules is necessitating the reintroduc-... 

If one were to hazard a guess as to where the major new developments in quantum chemistry will be in the next fifteen years, the proper treatment of relativity and the introduction of quantum electrodynamic effects seem to us to be likely candidates ... 

Quantum Electrodynamic Effects in Few-Electron Atomic Systems, G. W. F. Drake... 

We can mention only briefly, that hardly for He itself, but for the He isoelec-tronic series relativistic corrections and even QED (quantum electrodynamic) effects become important with increasing Z [41, 42, 43]. 

Abstract Rapid advances in quantum technology have made possible the control of quantum states of elementary material quantum systems, such as atoms or molecules, and of the electromagnetic radiation field resulting from spontaneous photon emission of their unstable excited states to such a level of precision that subtle quantum electrodynamical phenomena have become observable experimentally. Recent developments in the area of quantum information processing demonstrate that characteristic quantum electrodynamical effects can even be exploited for practical purposes provided the relevant electromagnetic field modes are controlled by appropriate cavities. A central problem in this context is the realization of an ideal transfer of quantum information between a state of a material quantum system and a quantum... 

Keywords Covariance Many-body perturbation Quantum-electrodynamical effects Electron correlation Fine structure Heliumlike ions... 

Przybytek, M., Cencek, W., Komasa, J., Lach, G., Jeziorski, B., Szalewicz, K. Relativistic and quantum electrodynamics effects in the hehum pair potential. Phys. Rev. Lett. 104, 183003 (2010)... 

The Breit corrections are sometimes classified as nonradiative effects in contrary to the radiative affects which are true quantum-electrodynamical effects due to the electron self energy and vacuum polarization [30-32]. 

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