Measuring orbital interaction using quantum information theory

TL;DR

This paper introduces a quantum information theory-based measure of orbital interaction, providing a new way to analyze chemical bonds and address the ordering problem in density-matrix renormalization group methods.

Contribution

It presents a straightforward method to compute orbital interactions using von Neumann entropies and demonstrates its application to chemical bonds and DMRG ordering.

Findings

Successfully tested for different chemical bonds

Provides a new tool for analyzing orbital interactions

Applied to the density-matrix renormalization group ordering problem

Abstract

Quantum information theory gives rise to a straightforward definition of the interaction of electrons $I_{p,q}$ in two orbitals $p$, $q$ for a given many-body wave function. A convenient way to calculate the von Neumann entropies needed is presented in this work, and the orbital interaction $I_{p,q}$ is successfully tested for different types of chemical bonds. As an example of an application of $I_{p,q}$ beyond the interpretation of wave functions, $I_{p,q}$ is then used to investigate the ordering problem in the density-matrix renormalization group.