Dynamical vertex approximation for retarded interactions: Application to the Hubbard-Holstein model
We extend the dynamical vertex approximation (D$\Gamma$A), in its most commonly used ladder-version, to systems with retarded electronic interactions. Such an extended scheme, which we name"dynamical-$U$ D$\Gamma$A", allows us to study strongly interacting electrons coupled to bosons including non-local spatial correla...