Extending the fair sampling assumption using causal diagrams
Discarding undesirable measurement results in Bell experiments opens the detection loophole that prevents a conclusive demonstration of nonlocality. As closing the detection loophole represents a major technical challenge for many practical Bell experiments, it is customary to assume the so-called f...
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| Format: | Article |
| Language: | English |
| Published: |
Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
2023-01-01
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| Series: | Quantum |
| Online Access: | https://quantum-journal.org/papers/q-2023-01-13-897/pdf/ |
| _version_ | 1797953607204601856 |
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| author | Valentin Gebhart Augusto Smerzi |
| author_facet | Valentin Gebhart Augusto Smerzi |
| author_sort | Valentin Gebhart |
| collection | DOAJ |
| description | Discarding undesirable measurement results in Bell experiments opens the detection loophole that prevents a conclusive demonstration of nonlocality. As closing the detection loophole represents a major technical challenge for many practical Bell experiments, it is customary to assume the so-called fair sampling assumption (FSA) that, in its original form, states that the collectively postselected statistics are a fair sample of the ideal statistics. Here, we analyze the FSA from the viewpoint of causal inference: We derive a causal structure that must be present in any causal model that faithfully encapsulates the FSA. This provides an easy, intuitive, and unifying approach that includes different accepted forms of the FSA and underlines what is really assumed when using the FSA. We then show that the FSA can not only be applied in scenarios with non-ideal detectors or transmission losses, but also in ideal experiments where only parts of the correlations are postselected, e.g., when the particles' destinations are in a superposition state. Finally, we demonstrate that the FSA is also applicable in multipartite scenarios that test for (genuine) multipartite nonlocality. |
| first_indexed | 2024-04-10T23:04:43Z |
| format | Article |
| id | doaj.art-88a468b5a2bb44d7896209cbf6ec1d48 |
| institution | Directory Open Access Journal |
| issn | 2521-327X |
| language | English |
| last_indexed | 2024-04-10T23:04:43Z |
| publishDate | 2023-01-01 |
| publisher | Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften |
| record_format | Article |
| series | Quantum |
| spelling | doaj.art-88a468b5a2bb44d7896209cbf6ec1d482023-01-13T11:44:10ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2023-01-01789710.22331/q-2023-01-13-89710.22331/q-2023-01-13-897Extending the fair sampling assumption using causal diagramsValentin GebhartAugusto SmerziDiscarding undesirable measurement results in Bell experiments opens the detection loophole that prevents a conclusive demonstration of nonlocality. As closing the detection loophole represents a major technical challenge for many practical Bell experiments, it is customary to assume the so-called fair sampling assumption (FSA) that, in its original form, states that the collectively postselected statistics are a fair sample of the ideal statistics. Here, we analyze the FSA from the viewpoint of causal inference: We derive a causal structure that must be present in any causal model that faithfully encapsulates the FSA. This provides an easy, intuitive, and unifying approach that includes different accepted forms of the FSA and underlines what is really assumed when using the FSA. We then show that the FSA can not only be applied in scenarios with non-ideal detectors or transmission losses, but also in ideal experiments where only parts of the correlations are postselected, e.g., when the particles' destinations are in a superposition state. Finally, we demonstrate that the FSA is also applicable in multipartite scenarios that test for (genuine) multipartite nonlocality.https://quantum-journal.org/papers/q-2023-01-13-897/pdf/ |
| spellingShingle | Valentin Gebhart Augusto Smerzi Extending the fair sampling assumption using causal diagrams Quantum |
| title | Extending the fair sampling assumption using causal diagrams |
| title_full | Extending the fair sampling assumption using causal diagrams |
| title_fullStr | Extending the fair sampling assumption using causal diagrams |
| title_full_unstemmed | Extending the fair sampling assumption using causal diagrams |
| title_short | Extending the fair sampling assumption using causal diagrams |
| title_sort | extending the fair sampling assumption using causal diagrams |
| url | https://quantum-journal.org/papers/q-2023-01-13-897/pdf/ |
| work_keys_str_mv | AT valentingebhart extendingthefairsamplingassumptionusingcausaldiagrams AT augustosmerzi extendingthefairsamplingassumptionusingcausaldiagrams |