Analytical ground state for the three-band Hubbard model

TL;DR

This paper derives a non-perturbative analytical approximation for the ground state of the three-band Hubbard model, accurately capturing charge properties in strongly correlated cuprates and facilitating easier analysis compared to numerical methods.

Contribution

The paper introduces a new analytical approximation for the ground state of the three-band Hubbard model, validated against quantum Monte Carlo results, and applicable to various geometries.

Findings

Accurately describes ground-state charge properties.

Preserves size consistency and is easily generalizable.

Validated by comparison with Quantum Monte Carlo calculations.

Abstract

For the calculation of charge excitations as those observed in, e.g., photo-emission spectroscopy or in electron-energy loss spectroscopy, a correct description of ground-state charge properties is essential. In strongly correlated systems like the undoped cuprates this is a highly non-trivial problem. In this paper we derive a non-perturbative analytical approximation for the ground state of the three-band Hubbard model on an infinite, half filled CuO_2 plane. By comparison with Projector Quantum Monte Carlo calculations it is shown that the resulting expressions correctly describe the charge properties of the ground state. Relations to other approaches are discussed. The analytical ground state preserves size consistency and can be generalized for other geometries, while still being both easy to interpret and to evaluate.