Interaction flow method reloaded

TL;DR

This paper extends the interaction flow method to analyze the two-dimensional Hubbard model away from half-filling, incorporating real-frequency self-energy feedback to improve understanding of physical properties.

Contribution

The paper introduces a modified interaction flow approach that includes real-frequency self-energy feedback, providing new insights into the Hubbard model's behavior.

Findings

Self-energy feedback significantly affects the flow of interactions.

Comparison shows real-frequency feedback yields different results than imaginary-frequency calculations.

Various physical and non-physical factors influence the outcomes qualitatively and quantitatively.

Abstract

A recently proposed extension of the interaction flow method is applied to exemplary cases of selected physical and methodical parameters for the two-dimensional Hubbard model away from half-filling and perfect nesting. In this scheme, the self-energy is calculated on the real-frequency axis and its feedback on the flow of interactions is included in a simple manner via a momentum-dependent quasi-particle weight. Results for two different types of self-energy feedback are compared to the case without feedback and to existing results stemming from calculations for imaginary frequencies. Various physical and non-physical aspects which influence the outcome qualitatively and quantitatively are addressed. Some tentative directions for future developments are suggested.