Quantification of correlations in quantum many-particle systems

TL;DR

This paper proposes a new, unbiased measure for quantifying correlations in quantum many-particle systems, demonstrated through applications to the Hubbard model and transition-metal oxides using dynamical mean-field theory.

Contribution

It introduces a novel correlation measure based on relative von Neumann entropy, applicable to various quantum systems and validated with practical examples.

Findings

Effective quantification of electron correlations in models and materials.

The measure distinguishes correlated from uncorrelated states reliably.

Application to real materials demonstrates practical utility.

Abstract

We introduce a well-defined and unbiased measure of the strength of correlations in quantum many-particle systems which is based on the relative von Neumann entropy computed from the density operator of correlated and uncorrelated states. The usefulness of this general concept is demonstrated by quantifying correlations of interacting electrons in the Hubbard model and in a series of transition-metal oxides using dynamical mean-field theory.