Diagrammatic self-energy approximations and the total particle number

A Schindlmayr, P Garcia-Gonzalez, R W Godby

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Abstract

There is increasing interest in many-body perturbation theory as a practical tool for the calculation of ground-state properties. As a consequence, unambiguous sum rules such as the conservation of particle number under the influence of the Coulomb interaction have acquired an importance that did not exist for calculations of excited-state properties. In this paper we obtain a rigorous, simple relation whose fulfilment guarantees particle-number conservation in a given diagrammatic self-energy approximation. Hedin's G(0)W(0) approximation does not satisfy this relation and hence violates the particle-number sum rule. Very precise calculations for the homogeneous electron gas and a model inhomogeneous electron system allow the extent of the nonconservation to be estimated.

Original languageEnglish
Article number235106
Pages (from-to)-
Number of pages6
JournalPhysical Review B
Volume64
Issue number23
DOIs
Publication statusPublished - 15 Dec 2001

Bibliographical note

© 2001 American Physical Society. Published in Physical Review B and uploaded in accordance with the publisher's self archiving policy.

Keywords

  • SPACE-TIME METHOD
  • ELECTRON-GAS
  • SPECTRAL FUNCTIONS
  • GW APPROXIMATION
  • BAND-GAPS
  • SEMICONDUCTORS
  • SURFACE
  • DENSITY
  • CONSERVATION
  • INSULATORS

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