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arXiv · 2112.06595

Self-testing quantum states via nonmaximal violation in Hardy's test of nonlocality

Ashutosh Rai·Matej Pivoluska·Souradeep Sasmal·Manik Banik·Sibasish Ghosh·Martin Plesch
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Abstract

Self-testing protocols enable certification of quantum devices without demanding full knowledge about their inner workings. A typical approach in designing such protocols is based on observing nonlocal correlations which exhibit maximum violation in a Bell test. We show that in Bell experiment known as Hardy's test of nonlocality not only the maximally nonlocal correlation self-tests a quantum state, rather a non-maximal nonlocal behavior can serve the same purpose. We, in fact, completely characterize all such behaviors leading to self-test of every pure two qubit entangled state except the maximally entangled ones. Apart from originating a novel self-testing protocol, our method provides a powerful tool towards characterizing the complex boundary of the set of quantum correlations.

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Ashutosh Rai, Matej Pivoluska, Souradeep Sasmal, Manik Banik, Sibasish Ghosh, Martin Plesch. 2021-12-13. Self-testing quantum states via nonmaximal violation in Hardy's test of nonlocality. https://doi.org/10.1103/physreva.105.052227

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