Skip to main content

Research Repository

Advanced Search

The controlled SWAP test for determining quantum entanglement

Foulds, Steph; Kendon, Viv; Spiller, Tim

The controlled SWAP test for determining quantum entanglement Thumbnail


Authors

Tim Spiller



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.

Citation

Foulds, S., Kendon, V., & Spiller, T. (2021). The controlled SWAP test for determining quantum entanglement. Quantum Science and Technology, 6(3), Article 035002. https://doi.org/10.1088/2058-9565/abe458

Journal Article Type Article
Acceptance Date Feb 8, 2021
Online Publication Date Apr 1, 2021
Publication Date 2021-07
Deposit Date Sep 8, 2021
Publicly Available Date Mar 28, 2024
Journal Quantum Science and Technology
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 6
Issue 3
Article Number 035002
DOI https://doi.org/10.1088/2058-9565/abe458

Files

Published Journal Article (Advance online version) (2.6 Mb)
PDF

Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
Advance online version Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.





You might also like



Downloadable Citations