TY - JOUR
AB - 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.
AU - Schindlmayr, Arno
AU - García-González, Pablo
AU - Godby, Rex William
ID - 18612
IS - 23
JF - Physical Review B
SN - 0163-1829
TI - Diagrammatic self-energy approximations and the total particle number
VL - 64
ER -