Numerical results for generalized RVB wavefunctions

TL;DR

This paper presents numerical analyses of a generalized RVB wavefunction incorporating ionic and covalent bonds, including non-nearest neighbors, with results showing high accuracy for the Hubbard model on small lattices.

Contribution

It introduces a generalized RVB wavefunction with ionic and covalent contributions and evaluates its effectiveness on small Hubbard lattices, considering symmetry and non-nearest bonds.

Findings

High overlap (0.999) with exact ground state at U=40

Good agreement with exact results for small lattices

Correlation functions match well with exact calculations

Abstract

Numerical results are presented for a generalized resonance valence bond state which includes both ionic and covalent contributions in each bond ; non nearest-neighbor bonds are also considered. Variational calculations have been performed and the space group symmetry has been taken into account. The results for the Hubbard Hamiltonian are compared with the exact ones for the $ 2 X 2 X 2 $ and the $ 4 X 4 $ lattices. The agreement is quite satisfactory for large values of the interaction U ( for U=40 the overlap with the exact ground state wave function is 0.999 ). Several correlation functions are also compared.