10.1103/PhysRevB.64.235106
Schindlmayr, Arno
Arno
Schindlmayr0000-0002-4855-071X
García-González, Pablo
Pablo
García-González
Godby, Rex William
Rex William
Godby
Diagrammatic self-energy approximations and the total particle number
American Physical Society
2001
2020-08-28T21:21:29Z
2020-08-30T21:18:18Z
journal_article
https://ris.uni-paderborn.de/record/18612
https://ris.uni-paderborn.de/record/18612.json
0163-1829
90160 bytes
application/pdf
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.