Correlated starting points for the functional renormalization group
Abstract
We present a general frame to extend functional renormalization group (fRG) based computational schemes by using an exactly solvable interacting reference problem as starting point for the RG flow. The systematic expansion around this solution accounts for a non-perturbative inclusion of correlations. Introducing auxiliary fermionic fields by means of a Hubbard-Stratonovich transformation, we derive the flow equations for the auxiliary fields and determine the relation to the conventional weak-coupling truncation of the hierarchy of flow equations. As a specific example we consider the dynamical mean-field theory (DMFT) solution as reference system, and discuss the relation to the recently introduced DMFRG and the dual-fermion formalism.
Cite
@article{arxiv.1411.1342,
title = {Correlated starting points for the functional renormalization group},
author = {Nils Wentzell and Ciro Taranto and Andrey A. Katanin and Alessandro Toschi and Sabine Andergassen},
journal= {arXiv preprint arXiv:1411.1342},
year = {2015}
}
Comments
14 pages, 6 figures