The controlled SWAP test for determining quantum entanglement

Foulds, Steph and Kendon, Viv and Spiller, Tim (2021) The controlled SWAP test for determining quantum entanglement. Quantum Science and Technology, 6 (3). 035002. ISSN 2058-9565 (https://doi.org/10.1088/2058-9565/abe458)

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Abstract

Quantum entanglement is essential to the development of quantum computation, communications, and technology. The controlled SWAP test, widely used for state comparison, can be adapted to an efficient and useful test for entanglement of a pure state. Here we show that the test can evidence the presence of entanglement (and further, genuine n-qubit entanglement), can distinguish entanglement classes, and that the concurrence of a two-qubit state is related to the test's output probabilities. We also propose a multipartite measure of entanglement that acts similarly for n-qubit states. The average number of copies of the test state required to detect entanglement decreases for larger systems, to four on average for many (n ⪆ 8) qubits for maximally entangled states. For non-maximally entangled states, the number of copies required to detect entanglement increases with decreasing entanglement. Furthermore, the results are robust to second order when typical small errors are introduced to the state under investigation.

ORCID iDs

Foulds, Steph, Kendon, Viv ORCID logoORCID: https://orcid.org/0000-0002-6551-3056 and Spiller, Tim;
  • Item type:Article
    ID code:78851
    Dates:
    Date
    Event
    1 April 2021
    Published
    8 February 2021
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:09 Dec 2021 13:54
    Last modified:17 Nov 2024 01:20
    URI:https://strathprints.strath.ac.uk/id/eprint/78851
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