On-site-interaction-induced Peak-dip-hump Characteristics with the Mean Field Theory + Perturbation Approach

TL;DR

This paper introduces a novel mean field and perturbation approach to analyze strong coupling models, successfully reproducing the peak-dip-hump spectral features observed in cuprates and aligning well with existing numerical methods.

Contribution

A new combined mean field and perturbation method for strong coupling models that simplifies analysis and reproduces complex spectral features.

Findings

Reproduces cuprate peak-dip-hump spectral characteristics

Aligns with quantum Monte Carlo and tensor network results

Validates the effectiveness of the new approach

Abstract

For decades, the difficulty of tackling a strong coupling model with a perturbative approach remained regardless of numerous inquiries. In the current work, a typical mean field theory procedure transforms a strong coupling Hamiltonian into a weak one, which can be solved within a perturbative approach. The Hamiltonian of 2-dimensional free electron gas with Hubbard on-site interaction is calculated as a test of the new procedure. Consequently, the spectral characteristics of the cuprates peak-dip-hump are reproduced. The result is compared with the past theoretical investigations, e.g., quantum Monte Carlo method, density matrix renormalization group, tensor network methods, etc., which agree well with the spectral curve.