Maximal qubit violation of n-locality inequalities in a star-shaped quantum network

• Autor(a) principal: Andreoli, Francesco
• Data de Publicação: 2017
• Outros Autores: Carvacho, Gonzalo, Santodonato, Luca, Araújo, Rafael Chaves Souto, Sciarrino, Fabio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/30391
• topic: Generalization of Bellʼs theorem; Non-bilocal correlations; Quantum network

Bellʼs theorem was a cornerstone for our understanding of quantum theory and the establishment of Bell non-locality played a crucial role in the development of quantum information. Recently, its extension to complex networks has been attracting growing attention, but a deep characterization of quantum behavior is still missing for this novel context. In this work we analyze quantum correlations arising in the bilocality scenario, that is a tripartite quantum network where the correlations between the parties are mediated by two independent sources of states. First, we prove that non-bilocal correlations witnessed through a Bell-state measurement in the central node of the network form a subset of those obtainable by means of a local projective measurement. This leads us to derive the maximal violation of the bilocality inequality that can be achieved by arbitrary two-qubit quantum states and arbitrary local projective measurements.Wethen analyze in details the relation between the violation of the bilocality inequality and theCHSHinequality. Finally, we show how our method can be extended to the n-locality scenario consisting of n two-qubit quantum states distributed among n + 1nodes of a star-shaped network