Local Realism, Non-Contextuality and Cloning
Abstract: One of the most basic properties of quantum information is that it cannot be copied. This is known variously as the no-cloning theorem or the monogamy of entanglement. Recently, it has been demonstrated that the property of monogamy so far seen for quantum correlations in composite entangled systems (Bell-Clauser-Horne-Shimony-Holt inequalities testing local realism) also carries over to single quantum systems (Klyachko-Can-Binicoğlu-Shumovsky inequalities testing non-contextuality). Violation of the latter type of inequalities has been shown to be related to a violation of causality analogous to the necessity of signaling between spatially separated systems for the violation of Bell monogamy relations. In this talk, it will be shown that no-signaling principle can be used to derive approximate quantum cloners.