Bell nonlocality in quantum networks with unreliable sources: Loophole-free postelection via self-testing

Fuente: arXiv
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Main Authors: Boreiri, Sadra, Brunner, Nicolas, Sekatski, Pavel
Format: Preprint
Published: 2025
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author Boreiri, Sadra
Brunner, Nicolas
Sekatski, Pavel
author_facet Boreiri, Sadra
Brunner, Nicolas
Sekatski, Pavel
contents We discuss Bell nonlocality in quantum networks with unreliable sources. Our main result is a condition on the observed data which ensures that inconclusive events can be safely discarded, without introducing any loophole. More formally, we characterize the fair-sampling property for measurements in a network. When all measurements are fair-sampling, we show that the post-selection of conclusive outcomes does not compromise the assumption of source independence, hence avoiding the detection loophole. Furthermore, we show that in some cases, the fair-sampling property can in fact be guaranteed based only on observed data. To show this, we prove that saturation of the Finner inequality provides a self-test of the underlying quantum model. We illustrate the relevance of our results by demonstrating an improvement in device-independent randomness generation for a photonic Bell test with a probabilistic source and for the triangle network.
format Preprint
id arxiv_https___arxiv_org_abs_2501_14027
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bell nonlocality in quantum networks with unreliable sources: Loophole-free postelection via self-testing
Boreiri, Sadra
Brunner, Nicolas
Sekatski, Pavel
Quantum Physics
We discuss Bell nonlocality in quantum networks with unreliable sources. Our main result is a condition on the observed data which ensures that inconclusive events can be safely discarded, without introducing any loophole. More formally, we characterize the fair-sampling property for measurements in a network. When all measurements are fair-sampling, we show that the post-selection of conclusive outcomes does not compromise the assumption of source independence, hence avoiding the detection loophole. Furthermore, we show that in some cases, the fair-sampling property can in fact be guaranteed based only on observed data. To show this, we prove that saturation of the Finner inequality provides a self-test of the underlying quantum model. We illustrate the relevance of our results by demonstrating an improvement in device-independent randomness generation for a photonic Bell test with a probabilistic source and for the triangle network.
title Bell nonlocality in quantum networks with unreliable sources: Loophole-free postelection via self-testing
topic Quantum Physics
url https://arxiv.org/abs/2501.14027