Combining the Extended Dynamical Mean Field Theory and the model GW method

Yoshio Kuramoto

Ping Sun, Gabriel Kotliar

We explore the combination of the extended dynamical mean field theory (EDMFT) with the GW approximation (GWA); the former sums the local contributions to the self-energies to infinite order in closed form and the latter handles the nonlocal ones to lowest order. We investigate the different levels of self-consistency that can be implemented within this method by comparing to the exact quantum Monte Carlo solution of a finite-size model Hamiltonian. We find that using the EDMFT solution for the local self-energies as input to the GWA for the nonlocal self-energies gives the best result.

K. Karlsson

We combine the single-site dynamical mean field theory (DMFT) with the non-local GW method. This is done fully self-consistently and we apply our formalism to a one-band Hubbard model. Eventually at self-consistency the full self-energy and polarization operator of the system are retrieved. Some numerical results, in the metallic as well as the insulator regime, are presented and briefly discussed. Depending on the involved interaction (GW) parameters, substantial changes are found when the GW self-energy is incorporated. However, the main point of this work is to demonstrate the applicability of the method, not to make any strict comparison with exact results and experiments.

Dieter Vollhardt, Krzysztof Byczuk, Marcus Kollar

F. Aryasetiawan, Fredrik Nilsson

In Chap. 7 the multitier downfolding scheme was introduced from a general perspective, and in Chap. 8 the combination of GWA (Chap. 4) with extended dynamical-mean field theory (Chap. 5), the so called GW+EDMFT method, was described. In this chapter the multitier scheme applied to GW+EDMFT will be discussed. For completeness we will begin by reintroducing the multitier machinery applied specifically to GW+EDMFT and then we review the most important results.