Cluster diagonalization in systematically expanded Hilbert spaces: application to models of correlated electrons

TL;DR

This paper introduces a cluster diagonalization method in systematically expanded Hilbert spaces, applied to models of correlated electrons like high-T_c superconductors, and compares its effectiveness with other existing techniques.

Contribution

It presents a novel cluster diagonalization approach in expanded Hilbert spaces for correlated electron models, linking it to perturbation and variational methods.

Findings

Results align with other techniques on truncated Hilbert spaces

Method effectively models high-T_c superconductor models

Provides insights into the relation with perturbation and variational methods

Abstract

A method of cluster diagonalization in a systematically expanded Hilbert space is described. We discuss some applications of this procedure to models of high-T_c superconductors, like the t - J and one and three bands Hubbard models in two dimensions. The results obtained with this method are compared against results obtained with other techniques dealing with truncated Hilbert spaces. The relation between this method of diagonalization in a reduced Hilbert space, and perturbation theory and variational techniques is also discussed.