THE SCREENING FUNCTION OF AN INTERACTING ELECTRON GAS

1966 ◽  
Vol 44 (9) ◽  
pp. 2137-2171 ◽  
Author(s):  
D. J. W. Geldart ◽  
S. H. Vosko
Keyword(s):  
Electron Gas ◽  
Substantial Contribution ◽  
Fundamental Relation ◽  
Many Body ◽  
Screening Constant ◽  
Self Energy ◽  
Self Consistent ◽  
Small Wave ◽  
Many Body Perturbation Theory ◽  
Zero Frequency

The screening function of an interacting electron gas at high and metallic densities is investigated by many-body perturbation theory. The analysis is guided by a fundamental relation between the compressibility of the system and the zero-frequency small wave-vector screening function (i.e. screening constant). It is shown that the contribution from a graph not included in previous work is essential to obtain the lowest-order correlation correction to the screening constant at high density. Also, this graph gives a substantial contribution to the screening constant at metallic densities. The general problem of choosing a self-consistent set of graphs for calculating the screening function is discussed in terms of a coupled set of integral equations for the propagator, the self-energy, the vertex function, and the screening function. A modification of Hubbard's (1957) form of the screening function is put forward on the basis of these results.

Towards numerical implementation of the relativistically covariant many-body perturbation theoryThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008.

2009 ◽  
Vol 87 (7) ◽  
pp. 817-824 ◽  
Author(s):  
Daniel Hedendahl ◽  
Ingvar Lindgren ◽  
Sten Salomonson
Keyword(s):  
Standard Procedure ◽  
Operator Method ◽  
Vertex Correction ◽  
Many Body ◽  
Atomic Systems ◽  
Self Energy ◽  
Electron Positron ◽  
Many Body Perturbation Theory ◽  
Qed Effects ◽  
First Time

The standard procedure for relativistic many-body perturbation theory (RMBPT) is not relativistically covariant, and the effects of retardation, virtual-electron-positron-pair, and radiative effects (self-energy, vacuum polarisation, and vertex correction) — the so-called QED effects — are left out. The energy contribution from the QED effects can be evaluated by the covariant evolution operator method, which has a structure that is similar to that of RMBPT, and it can serve as a merger between QED and RMBPT. The new procedure makes it, in principle, possible for the first time to evaluate QED effects together with correlation to high order. The procedure is now being implemented, and it has been shown that the effect of electron correlation on first-order QED for He-like neon dominates heavily over second-order QED effects.

Self‐consistent many‐body theory of π‐electron systems. II. Self‐energy effects

1979 ◽  
Vol 70 (9) ◽  
pp. 4086-4090 ◽  
Author(s):  
Marcello Baldo ◽  
Renato Pucci ◽  
Pasquale Tomasello
Keyword(s):  
Electron Systems ◽  
Many Body ◽  
Self Energy ◽  
Many Body Theory ◽  
Self Consistent ◽  
Body Theory

scholarly journals Spectra and total energies from self-consistent many-body perturbation theory

1998 ◽  
Vol 58 (19) ◽  
pp. 12684-12690 ◽  
Author(s):  
Arno Schindlmayr ◽  
Thomas J. Pollehn ◽  
R. W. Godby
Keyword(s):  
Perturbation Theory ◽  
Many Body ◽  
Self Consistent ◽  
Many Body Perturbation Theory ◽  
Total Energies

scholarly journals Design of auxiliary systems for spectroscopy

2020 ◽  
Vol 224 ◽  
pp. 424-447
Author(s):  
Marco Vanzini ◽  
Francesco Sottile ◽  
Igor Reshetnyak ◽  
Sergio Ciuchi ◽  
Lucia Reining ◽  
...  
Keyword(s):  
Spectral Properties ◽  
Density Functional ◽  
The Self ◽  
Many Body ◽  
Functional Theory ◽  
Correlation Kernel ◽  
Effective Potentials ◽  
Exchange Correlation ◽  
Self Energy ◽  
Many Body Perturbation Theory

In this contribution, we advocate the possibility of designing auxiliary systems with effective potentials or kernels that target only the specific spectral properties of interest and are simpler than the self-energy of many-body perturbation theory or the exchange–correlation kernel of time-dependent density-functional theory.

THE PAIR DISTRIBUTION FUNCTION OF AN INTERACTING ELECTRON GAS

1967 ◽  
Vol 45 (9) ◽  
pp. 3139-3161 ◽  
Author(s):  
D. J. W. Geldart
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Electron Gas ◽  
Pauli Principle ◽  
Distribution Functions ◽  
Upper And Lower Bounds ◽  
Wave Number ◽  
Many Body ◽  
Many Body Perturbation Theory ◽  
Simple Class

The pair distribution function, in the limit of zero separation, of an interacting electron gas at high and metallic densities is investigated by many-body perturbation theory. It is shown that the usual methods for maintaining self-consistency in approximate calculations violate, in general, the nonnegativity of the pair distribution function. In particular, the Pauli principle yields a rigorous sum rule for the parallel spin density fluctuation propagator which is not satisfied. Upper and lower bounds on one-loop and multiloop contributions to the pair distribution functions are given. These bounds are used to discuss correlation corrections. An improved wave-number dependence is given for Hubbard's (1957) approximation to the screening function and numerical results are given for a simple class of exchange corrections.

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