Total correlations and mutual information

TL;DR

This paper challenges the common view that quantum mutual information universally measures total correlations in bipartite quantum states and proposes an alternative measure for certain states.

Contribution

It demonstrates that quantum mutual information is not always an accurate measure of total correlations and introduces a new method for quantifying them in specific cases.

Findings

Quantum mutual information does not always measure total correlations.

A new measure for total correlations is proposed for certain quantum states.

The paper highlights limitations of existing correlation measures in quantum information theory.

Abstract

In quantum information theory it is generally accepted that quantum mutual information is an information-theoretic measure of total correlations of a bipartite quantum state. We argue that there exist quantum states for which quantum mutual information cannot be considered as a measure of total correlations. Moreover, for these states we propose a different way of quantifying total correlations.