Unified scheme for correlations using linear relative entropy

TL;DR

This paper introduces a unified approach using linear relative entropy to quantify various correlations in bipartite quantum systems, providing explicit formulas and a closed additive relation.

Contribution

It presents a novel unified scheme for quantifying correlations in quantum systems using linear relative entropy, with explicit calculations for symmetric two-qubit states.

Findings

Derived explicit expressions for total, classical, and quantum correlations.

Established a closed additive relation among different correlations.

Applied the scheme to a symmetric two-qubit state with parity and exchange symmetries.

Abstract

A linearized variant of relative entropy is used to quantify in a unified scheme the different kinds of correlations in a bipartite quantum system. As illustration, we consider a two-qubit state with parity and exchange symmetries for which we determine the total, classical and quantum correlations. We also give the explicit expressions of its closest product state, closest classical state and the corresponding closest product state. A closed additive relation, involving the various correlations quantified by linear relative entropy, is derived.