{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,15]],"date-time":"2025-12-15T19:44:56Z","timestamp":1765827896791,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,4,11]],"date-time":"2020-04-11T00:00:00Z","timestamp":1586563200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100014440","name":"Ministerio de Ciencia, Innovaci\u00f3n y Universidades","doi-asserted-by":"publisher","award":["PGC2018-095862-B-C22"],"award-info":[{"award-number":["PGC2018-095862-B-C22"]}],"id":[{"id":"10.13039\/100014440","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>We present a quantum circuit that transforms an unknown three-qubit state into its canonical form, up to relative phases, given many copies of the original state. The circuit is made of three single-qubit parametrized quantum gates, and the optimal values for the parameters are learned in a variational fashion. Once this transformation is achieved, direct measurement of outcome probabilities in the computational basis provides an estimate of the tangle, which quantifies genuine tripartite entanglement. We perform simulations on a set of random states under different noise conditions to asses the validity of the method.<\/jats:p>","DOI":"10.3390\/e22040436","type":"journal-article","created":{"date-parts":[[2020,4,13]],"date-time":"2020-04-13T04:45:31Z","timestamp":1586753131000},"page":"436","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Measuring the Tangle of Three-Qubit States"],"prefix":"10.3390","volume":"22","author":[{"given":"Adri\u00e1n","family":"P\u00e9rez-Salinas","sequence":"first","affiliation":[{"name":"Departament de F\u00edsica Qu\u00e0ntica i Astrof\u00edsica and Institut de Ci\u00e8ncies del Cosmos (ICCUB), Universitat de Barcelona, Mart\u00ed i Franqu\u00e8s 1, 08028 Barcelona, Spain"},{"name":"Barcelona Supercomputing Center, 08034 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Diego","family":"Garc\u00eda-Mart\u00edn","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica Qu\u00e0ntica i Astrof\u00edsica and Institut de Ci\u00e8ncies del Cosmos (ICCUB), Universitat de Barcelona, Mart\u00ed i Franqu\u00e8s 1, 08028 Barcelona, Spain"},{"name":"Barcelona Supercomputing Center, 08034 Barcelona, Spain"},{"name":"Instituto de F\u00edsica Te\u00f3rica, UAM-CSIC, 28049 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1041-2044","authenticated-orcid":false,"given":"Carlos","family":"Bravo-Prieto","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica Qu\u00e0ntica i Astrof\u00edsica and Institut de Ci\u00e8ncies del Cosmos (ICCUB), Universitat de Barcelona, Mart\u00ed i Franqu\u00e8s 1, 08028 Barcelona, Spain"},{"name":"Barcelona Supercomputing Center, 08034 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jos\u00e9","family":"Latorre","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica Qu\u00e0ntica i Astrof\u00edsica and Institut de Ci\u00e8ncies del Cosmos (ICCUB), Universitat de Barcelona, Mart\u00ed i Franqu\u00e8s 1, 08028 Barcelona, Spain"},{"name":"Center for Quantum Technologies, National University of Singapore, Singapore 119077, Singapore"},{"name":"Technology Innovation Institute, Abu Dhabi, UAE"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,11]]},"reference":[{"key":"ref_1","unstructured":"Nielsen, M.A., and Chuang, I.L. 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