Certificação entrópica de não-classicalidade em uma rede quântica com fontes independentes

Abstract

In this work, an approach based on classical information theory is used to certify the nonclassicality of correlations in a quantum network with two independent sources distributing particles in entangled states to three distant laboratories, where experimenters have access to certain measurement choices on their respective parts of the system. The certification of nonclassicality is carried out by optimizing the quantum value of bilocal entropic expressions over states and measurements, and identifying the cases in which this value exceeds the classical bound expressed by entropic bilocal inequalities. From this, the values of state parameters and measurement operators that maximize the quantum violations of these inequalities are determined, in the cases where such violations occur. These violations imply that the correlations in question cannot be explained by classical models compatible with this network structure, and also demonstrate the viability of the entropic approach as an alternative method for certifying nonclassicality, particularly well-suited for networks with independent sources.