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arXiv · 0805.4674

Self-consistent Spectral Function for Non-Degenerate Coulomb Systems and Analytic Scaling Behaviour

Carsten Fortmann
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Abstract

Novel results for the self-consistent single-particle spectral function and self-energy are presented for non-degenerate one-component Coulomb systems at various densities and temperatures. The GW^0-method for the dynamical self-energy is used to include many-particle correlations beyond the quasi-particle approximation. The self-energy is analysed over a broad range of densities and temperatures (n=10^17/cm^3-10^27/cm^3, T=10^2 eV/k_B-10^4 eV/k_B). The spectral function shows a systematic behaviour, which is determined by collective plasma modes at small wavenumbers and converges towards a quasi-particle resonance at higher wavenumbers. In the low density limit, the numerical results comply with an analytic scaling law that is presented for the first time. It predicts a power-law behaviour of the imaginary part of the self-energy, Im Sigma ~ -n^(1/4). This resolves a long time problem of the quasi-particle approximation which yields a finite self-energy at vanishing density.

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Carsten Fortmann. 2008-05-30. Self-consistent Spectral Function for Non-Degenerate Coulomb Systems and Analytic Scaling Behaviour. https://doi.org/10.1088/1751-8113%2F41%2F44%2F445501

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