Computing local multipoint correlators using the numerical renormalization group

Abstract

Here, G, K, and S each have only − 1 independent arguments, with ω and ω p = (ω 1 ,..., ω ) understood to obey energy conservation, ω 1••• = 0 and ω 1••• = 0. The ZF convolution kernel K can be chosen as

Parametrizations of local vertex corrections from weak to strong coupling: importance of the Hedin three-leg vertex

“…Indeed, the full two-particle information can be reconstructed from the residual vertex [91], including the corresponding fingerprints of the local moment [75]. However, further investigation is required, for example, an intriguing option is to study the residual vertex of the SBE decomposition on the real axis [46,47].…”

“…Previously, this correlation function has been calculated using a variety of different methods, for example, full exact diagonalization (ED, [40]), Lanczos ED [45], CTQMC, and, very recently, the numerical renormalization group (NRG, [46,47]). All these methods have in common that the evaluation of f is computationally expensive, in fact, at the present stage only CTQMC solvers are applicable in multi-orbital settings [48,49].…”