Spectral function of the 2D Hubbard model: a density matrix renormalization group plus cluster perturbation theory study

TL;DR

This paper combines cluster perturbation theory and density matrix renormalization group methods to analyze the spectral function of the 2D Hubbard model, revealing detailed dispersion features and pseudogap phenomena with high resolution.

Contribution

It introduces a novel approach integrating DMRG and cluster perturbation theory to study the 2D Hubbard model's spectral function with unprecedented resolution.

Findings

Reconstructed 2D dispersion matches quantum Monte Carlo results.

Identified kinks and pseudogap features linked to spin-charge scattering.

Achieved high-resolution spectral data using large 2xL ladders.

Abstract

We study the spectral function of the 2D Hubbard model using cluster perturbation theory, and the density matrix renormalization group as a cluster solver. We reconstruct the two-dimensional dispersion at, and away from half-filling using 2xL ladders, with L up to 80 sites, yielding results with unprecedented resolution in excellent agreement with quantum Monte Carlo. The main features of the spectrum can be described with a mean-field dispersion, while kinks and pseudogap traced back to scattering between spin and charge degrees of freedom.