@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}},
}