Maximal mutual correlation: an algebraic measure of correlations in bipartite quantum systems

TL;DR

This paper introduces the maximal mutual correlation, an algebraic measure that quantifies how much a bipartite quantum state deviates from a product state, capturing both quantum and classical correlations.

Contribution

The paper proposes a new algebraic measure of correlations in bipartite quantum systems that detects both quantum and classical correlations, unlike entanglement or discord.

Findings

Maximal mutual correlation can be non-zero for classically correlated states.

It provides a different perspective on correlations beyond entanglement.

The measure distinguishes between quantum and classical correlations.

Abstract

We introduce an algebraic measure of correlations in bipartite quantum systems. The proposed quantity, called maximal mutual correlation, provides the information how much a given state differs from the product state of its marginals. In contrast to the entanglement or quantum discord, maximal mutual correlation can be non - zero for some classically correlated quantum states.