{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T07:33:06Z","timestamp":1781681586448,"version":"3.54.5"},"reference-count":26,"publisher":"Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften","license":[{"start":{"date-parts":[[2020,2,6]],"date-time":"2020-02-06T00:00:00Z","timestamp":1580947200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Quantum"],"abstract":"<jats:p>A single qubit provides sufficient computational capabilities to construct a universal quantum classifier when assisted with a classical subroutine. This fact may be surprising since a single qubit only offers a simple superposition of two states and single-qubit gates only make a rotation in the Bloch sphere. The key ingredient to circumvent these limitations is to allow for multiple<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mtext class=\"MJX-tex-mathit\" mathvariant=\"italic\">data re-uploading<\/mml:mtext><\/mml:mrow><\/mml:math>. A quantum circuit can then be organized as a series of data re-uploading and single-qubit processing units. Furthermore, both data re-uploading and measurements can accommodate multiple dimensions in the input and several categories in the output, to conform to a universal quantum classifier. The extension of this idea to several qubits enhances the efficiency of the strategy as entanglement expands the superpositions carried along with the classification. Extensive benchmarking on different examples of the single- and multi-qubit quantum classifier validates its ability to describe and classify complex data.<\/jats:p>","DOI":"10.22331\/q-2020-02-06-226","type":"journal-article","created":{"date-parts":[[2020,2,6]],"date-time":"2020-02-06T15:00:26Z","timestamp":1581001226000},"page":"226","source":"Crossref","is-referenced-by-count":574,"title":["Data re-uploading for a universal quantum classifier"],"prefix":"10.22331","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5430-6468","authenticated-orcid":false,"given":"Adri\u00e1n","family":"P\u00e9rez-Salinas","sequence":"first","affiliation":[{"name":"Barcelona Supercomputing Center"},{"name":"Institut de Ci\u00e8ncies del Cosmos, Universitat de Barcelona, Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8835-2910","authenticated-orcid":false,"given":"Alba","family":"Cervera-Lierta","sequence":"additional","affiliation":[{"name":"Barcelona Supercomputing Center"},{"name":"Institut de Ci\u00e8ncies del Cosmos, Universitat de Barcelona, Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0411-9757","authenticated-orcid":false,"given":"Elies","family":"Gil-Fuster","sequence":"additional","affiliation":[{"name":"Dept. F\u00edsica Qu\u00e0ntica i Astrof\u00edsica, Universitat de Barcelona, Barcelona, Spain."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1702-7018","authenticated-orcid":false,"given":"Jos\u00e9 I.","family":"Latorre","sequence":"additional","affiliation":[{"name":"Barcelona Supercomputing Center"},{"name":"Institut de Ci\u00e8ncies del Cosmos, Universitat de Barcelona, Barcelona, Spain"},{"name":"Nikhef Theory Group, Science Park 105, 1098 XG Amsterdam, The Netherlands."},{"name":"Center for Quantum Technologies, National University of Singapore, Singapore."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"9598","published-online":{"date-parts":[[2020,2,6]]},"reference":[{"key":"0","doi-asserted-by":"publisher","unstructured":"M. Schuld, I. Sinayskiy, and F. Petruccione, Quantum Information Processing 13, 2567 (2014).","DOI":"10.1007\/s11128-014-0809-8"},{"key":"1","doi-asserted-by":"publisher","unstructured":"K. H. 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