Abstract We recently applied the coupled‐cluster method (CCM) with considerable success to several novel quantum spin‐lattice systems in the infinite bulk limit. In this article, we extend our CCM analysis to the electronic Hubbard models. In particular, based on a systematic approximation scheme within the CCM, we investigate the zero‐temperature properties of Hubbard models at half‐filling and with a single hole on a general bipartite lattice. Our aim was to provide the CCM framework for a systematic calculation of the properties of Hubbard models. © 1995 John Wiley & Sons, Inc.Abstract We recently applied the coupled‐cluster method (CCM) with considerable success to several novel quantum spin‐lattice systems in the infinite bulk limit. In this article, we extend our CCM analysis to the electronic Hubbard models. In particular, based on a systematic approximation scheme within the CCM, we investigate the zero‐temperature properties of Hubbard models at half‐filling and with a single hole on a general bipartite lattice. Our aim was to provide the CCM framework for a systematic calculation of the properties of Hubbard models. © 1995 John Wiley & Sons, Inc.

International Journal of Quantum ChemistryJul 15, 19958 citations

On a cluster approach to the hubbard model

J. Monecke

physica status solidi (b)May 1, 19739 citations

Coupled-cluster approach to electron correlations in the two-dimensional Hubbard model

Yoshihiro Asai, Hideki Katagiri

We have studied electron correlations in the doped two-dimensional (2D) Hubbard model by using the coupled-cluster method (CCM) to investigate whether or not the method can be applied to correct the independent particle approximations actually used in ab initio band calculations. The double excitation version of the CCM, implemented using the approximate coupled pair (ACP) method, accounts for most of the correlation energies of the 2D Hubbard model in the weak $(U/t\ensuremath{\simeq}1)$ and the intermediate $U/t$ regions $(U/t\ensuremath{\simeq}4).$ The error in this case is always less than $1%.$ The ACP approximation gets less accurate for large $U/t$ $(U/t\ensuremath{\simeq}8)$ and near half-filling. Further incorporation of electron correlation effects is necessary in this region. The accuracy depends neither on the system size, nor the gap between the lowest unoccupied level and the highest occupied level in the finite size effect. Hence, the CCM may be favorably applied to ab initio band calculations on metals as well as semiconductors and insulators.We have studied electron correlations in the doped two-dimensional (2D) Hubbard model by using the coupled-cluster method (CCM) to investigate whether or not the method can be applied to correct the independent particle approximations actually used in ab initio band calculations. The double excitation version of the CCM, implemented using the approximate coupled pair (ACP) method, accounts for most of the correlation energies of the 2D Hubbard model in the weak $(U/t\ensuremath{\simeq}1)$ and the intermediate $U/t$ regions $(U/t\ensuremath{\simeq}4).$ The error in this case is always less than $1%.$ The ACP approximation gets less accurate for large $U/t$ $(U/t\ensuremath{\simeq}8)$ and near half-filling. Further incorporation of electron correlation effects is necessary in this region. The accuracy depends neither on the system size, nor the gap between the lowest unoccupied level and the highest occupied level in the finite size effect. Hence, the CCM may be favorably applied to ab initio band calculations on metals as well as semiconductors and insulators.

arXiv:cond-mat/9904400Physical review. B, Condensed matterNov 15, 19996 citations

Physics of the Hubbard model solved with the cluster method

Lorenzo Fratino

Sep 17, 20180 citations

U/t

regions $(U/t\ensuremath{\simeq}4).$ The error in this case is always less than

1%.

The ACP approximation gets less accurate for large

U/t

$(U/t\ensuremath{\simeq}8)$ and near half-filling. Further incorporation of electron correlation effects is necessary in this region. The accuracy depends neither on the system size, nor the gap between the lowest unoccupied level and the highest occupied level in the finite size effect. Hence, the CCM may be favorably applied to ab initio band calculations on metals as well as semiconductors and insulators.