@article{18612,
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 G0W0 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.},
author = {Schindlmayr, Arno and García-González, Pablo and Godby, Rex William},
issn = {1095-3795},
journal = {Physical Review B},
number = {23},
publisher = {American Physical Society},
title = {{Diagrammatic self-energy approximations and the total particle number}},
doi = {10.1103/PhysRevB.64.235106},
volume = {64},
year = {2001},
}