On the local and non-local content of bipartite qubit and qutrit correlations

TL;DR

This paper investigates the local and non-local parts of quantum correlations in bipartite qubit and qutrit systems using a specific theoretical approach, revealing how local content varies with state parameters.

Contribution

It provides a detailed analysis of local and non-local content in bipartite qubit and qutrit states, extending previous methods to new classes of states and quantifying local content bounds.

Findings

Local content for pure two-qubit states varies with theta

Non-zero local content appears in certain two-qutrit states for gamma>2

Quantitative bounds on local content for specific quantum states

Abstract

The local and non-local contents of non-local probability distributions are studied using the approach of Elitzur, Popescu and Rohrlich [Phys. Lett. A \textbf{162}, 25 (1992)]. This work focuses on distributions that can be obtained by single-copy von Neumann measurements on bipartite quantum systems. For pure two-qubit states Psi(theta)=cos(theta)|00>+sin(theta)|11>, with cos(theta)>=sin(theta), the local content of the corresponding probability distribution is found to lie between 1-sin(2*theta) and cos(2*theta). For the family Psi(gamma)= (|00>+|11>+gamma*|22>)/sqrt(2+gamma^2) of two-qutrit states, non-zero local content is found for gamma>2.