GW approximations and vertex corrections on the Keldysh time-loop contour : Application for model systems at equilibrium
We study the effects of self-consistency and vertex corrections on different GW-based approximations for model systems of interacting electrons. For dealing with the most general case, we use the Keldysh time-loop contour formalism to evaluate the single-particle Green's functions. We provide the formal extension of Hedin's GW equations for the Green's function in the Keldysh formalism. We show an