Semi-device-independent certification of indefinite causal order
When transforming pairs of independent quantum operations according to the fundamental rules of quantum theory, an intriguing phenomenon emerges: some such higher-order operations may act on the input operations in an indefinite causal order. Recently, the formalism of process matrices has been deve...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
2019-08-01
|
| Series: | Quantum |
| Online Access: | https://quantum-journal.org/papers/q-2019-08-19-176/pdf/ |
| _version_ | 1818449351425392640 |
|---|---|
| author | Jessica Bavaresco Mateus Araújo Časlav Brukner Marco Túlio Quintino |
| author_facet | Jessica Bavaresco Mateus Araújo Časlav Brukner Marco Túlio Quintino |
| author_sort | Jessica Bavaresco |
| collection | DOAJ |
| description | When transforming pairs of independent quantum operations according to the fundamental rules of quantum theory, an intriguing phenomenon emerges: some such higher-order operations may act on the input operations in an indefinite causal order. Recently, the formalism of process matrices has been developed to investigate these noncausal properties of higher-order operations. This formalism predicts, in principle, statistics that ensure indefinite causal order even in a device-independent scenario, where the involved operations are not characterised. Nevertheless, all physical implementations of process matrices proposed so far require full characterisation of the involved operations in order to certify such phenomena. Here we consider a semi-device-independent scenario, which does not require all operations to be characterised. We introduce a framework for certifying noncausal properties of process matrices in this intermediate regime and use it to analyse the quantum switch, a well-known higher-order operation, to show that, although it can only lead to causal statistics in a device-independent scenario, it can exhibit noncausal properties in semi-device-independent scenarios. This proves that the quantum switch generates stronger noncausal correlations than it was previously known. |
| first_indexed | 2024-12-14T20:34:02Z |
| format | Article |
| id | doaj.art-0c1ee818177241cf800140521b8455ab |
| institution | Directory Open Access Journal |
| issn | 2521-327X |
| language | English |
| last_indexed | 2024-12-14T20:34:02Z |
| publishDate | 2019-08-01 |
| publisher | Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften |
| record_format | Article |
| series | Quantum |
| spelling | doaj.art-0c1ee818177241cf800140521b8455ab2022-12-21T22:48:27ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2019-08-01317610.22331/q-2019-08-19-17610.22331/q-2019-08-19-176Semi-device-independent certification of indefinite causal orderJessica BavarescoMateus AraújoČaslav BruknerMarco Túlio QuintinoWhen transforming pairs of independent quantum operations according to the fundamental rules of quantum theory, an intriguing phenomenon emerges: some such higher-order operations may act on the input operations in an indefinite causal order. Recently, the formalism of process matrices has been developed to investigate these noncausal properties of higher-order operations. This formalism predicts, in principle, statistics that ensure indefinite causal order even in a device-independent scenario, where the involved operations are not characterised. Nevertheless, all physical implementations of process matrices proposed so far require full characterisation of the involved operations in order to certify such phenomena. Here we consider a semi-device-independent scenario, which does not require all operations to be characterised. We introduce a framework for certifying noncausal properties of process matrices in this intermediate regime and use it to analyse the quantum switch, a well-known higher-order operation, to show that, although it can only lead to causal statistics in a device-independent scenario, it can exhibit noncausal properties in semi-device-independent scenarios. This proves that the quantum switch generates stronger noncausal correlations than it was previously known.https://quantum-journal.org/papers/q-2019-08-19-176/pdf/ |
| spellingShingle | Jessica Bavaresco Mateus Araújo Časlav Brukner Marco Túlio Quintino Semi-device-independent certification of indefinite causal order Quantum |
| title | Semi-device-independent certification of indefinite causal order |
| title_full | Semi-device-independent certification of indefinite causal order |
| title_fullStr | Semi-device-independent certification of indefinite causal order |
| title_full_unstemmed | Semi-device-independent certification of indefinite causal order |
| title_short | Semi-device-independent certification of indefinite causal order |
| title_sort | semi device independent certification of indefinite causal order |
| url | https://quantum-journal.org/papers/q-2019-08-19-176/pdf/ |
| work_keys_str_mv | AT jessicabavaresco semideviceindependentcertificationofindefinitecausalorder AT mateusaraujo semideviceindependentcertificationofindefinitecausalorder AT caslavbrukner semideviceindependentcertificationofindefinitecausalorder AT marcotulioquintino semideviceindependentcertificationofindefinitecausalorder |