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arXiv · 1904.08943

Bounding the sets of classical and quantum correlations in networks

Alejandro Pozas-Kerstjens·Rafael Rabelo·Łukasz Rudnicki·Rafael Chaves·Daniel Cavalcanti·Miguel Navascues·Antonio Acín
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Abstract

We present a method that allows the study of classical and quantum correlations in networks with causally-independent parties, such as the scenario underlying entanglement swapping. By imposing relaxations of factorization constraints in a form compatible with semidefinite programming, it enables the use of the Navascués-Pironio-Acín hierarchy in complex quantum networks. We first show how the technique successfully identifies correlations not attainable in the entanglement-swapping scenario. Then we use it to show how the nonlocal power of measurements can be activated in a network: there exist measuring devices that, despite being unable to generate nonlocal correlations in the standard Bell scenario, provide a classical-quantum separation in an entanglement swapping configuration.

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Alejandro Pozas-Kerstjens, Rafael Rabelo, Łukasz Rudnicki, Rafael Chaves, Daniel Cavalcanti, Miguel Navascues, Antonio Acín. 2019-10-07. Bounding the sets of classical and quantum correlations in networks. https://doi.org/10.1103/physrevlett.123.140503

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