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arXiv · 0907.2170

Device independent state estimation based on Bell's inequalities

C. -E. Bardyn·T. C. H. Liew·S. Massar·M. McKague·V. Scarani
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Abstract

The only information available about an alleged source of entangled quantum states is the amount $S$ by which the Clauser-Horne-Shimony-Holt (CHSH) inequality is violated: nothing is known about the nature of the system or the measurements that are performed. We discuss how the quality of the source can be assessed in this black-box scenario, as compared to an ideal source that would produce maximally entangled states (more precisely, any state for which $S=2\sqrt{2}$). To this end, we introduce several inequivalent notions of fidelity, each one related to the use one can make of the source after having assessed it; and we derive quantitative bounds for each of them in terms of the violation $S$. We also derive a lower bound on the entanglement of the source as a function of $S$ only.

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C. -E. Bardyn, T. C. H. Liew, S. Massar, M. McKague, V. Scarani. 2009-07-13. Device independent state estimation based on Bell's inequalities. https://doi.org/10.1103/physreva.80.062327

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