Local content of bipartite qubit correlations

Abstract

One of the last open problems concerning two qubits in a pure state is to find the exact local content of their correlation, in the sense of Elitzur, Popescu, and Rohrlich (EPR2). We propose an EPR2 decomposition that allows us to prove, for a wide range of states |ψ(θ)=cosθ|00+sinθ|11, that their local content is pL̄(θ)=cos2θ. We also share reflections on how to possibly extend this result to all two-qubit pure states. © 2010 The American Physical Society.