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 language | English |
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Article number | 235106 |
Pages (from-to) | - |
Number of pages | 6 |
Journal | Physical Review B |
Volume | 64 |
Issue number | 23 |
DOIs | |
Publication status | Published - 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