Resonating Valence Bond wave function: from lattice models to realistic systems

TL;DR

This paper discusses the resonating valence bond (RVB) wave function as a powerful variational approach for modeling strongly correlated systems, successfully bridging lattice models and realistic molecules like benzene.

Contribution

It demonstrates the effectiveness of the RVB wave function in capturing electron correlations in both lattice and molecular systems, with computational efficiency comparable to standard methods.

Findings

RVB wave function accurately predicts energies and geometries of molecules.

RVB approach captures key features of strongly correlated antiferromagnetic systems.

Computational cost scales similarly to Hartree-Fock and DFT methods.

Abstract

Although mean field theories have been very successful to predict a wide range of properties for solids, the discovery of high temperature superconductivity in cuprates supported the idea that strongly correlated materials cannot be qualitatively described by a mean field approach. After the original proposal by Anderson, there is now a large amount of numerical evidence that the simple but general resonating valence bond (RVB) wave function contains just those ingredients missing in uncorrelated theories, so that the main features of electron correlation can be captured by the variational RVB approach. Strongly correlated antiferromagnetic (AFM) systems, like Cs2CuCl4, displaying unconventional features of spin fractionalization, are also understood within this variational scheme. From the computational point of view the remarkable feature of this approach is that several resonating valence bonds can be dealt simultaneously with a single determinant, at a computational cost growing with the number of electrons similarly to more conventional methods, such as Hartree-Fock or Density Functional Theory. Recently several molecules have been studied by using the RVB wave function; we have always obtained total energies, bonding lengths and binding energies comparable with more demanding multi configurational methods, and in some cases much better than single determinantal schemes. Here we present the paradigmatic case of benzene.