From infinite to two dimensions through the functional renormalization group

TL;DR

This paper introduces a new combined method merging DMFT and fRG to non-perturbatively analyze strongly correlated fermions, effectively capturing local and non-local correlations in two-dimensional systems.

Contribution

The paper proposes a novel hybrid approach integrating DMFT and fRG, enabling unbiased, non-perturbative treatment of strongly correlated fermions with systematic non-local correlation inclusion.

Findings

Successful numerical application to the 2D Hubbard model at half-filling

Demonstrates feasibility of the combined DMFT and fRG approach

Provides insights into non-local correlations in strongly correlated systems

Abstract

We present a novel scheme for an unbiased and non-perturbative treatment of strongly correlated fermions. The proposed approach combines two of the most successful many-body methods, i.e., the dynamical mean field theory (DMFT) and the functional renormalization group (fRG). Physically, this allows for a systematic inclusion of non-local correlations via the flow equations of the fRG, after the local correlations are taken into account non-perturbatively by the DMFT. To demonstrate the feasibility of the approach, we present numerical results for the two-dimensional Hubbard model at half-filling.