{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,11]],"date-time":"2026-05-11T17:21:20Z","timestamp":1778520080758,"version":"3.51.4"},"reference-count":82,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,4,2]],"date-time":"2021-04-02T00:00:00Z","timestamp":1617321600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Prediction is the making of statements, usually probabilistic, about future events based on current information. Retrodiction is the making of statements about past events based on current information. We present the foundations of quantum retrodiction and highlight its intimate connection with the Bayesian interpretation of probability. The close link with Bayesian methods enables us to explore controversies and misunderstandings about retrodiction that have appeared in the literature. To be clear, quantum retrodiction is universally applicable and draws its validity directly from conventional predictive quantum theory coupled with Bayes\u2019 theorem.<\/jats:p>","DOI":"10.3390\/sym13040586","type":"journal-article","created":{"date-parts":[[2021,4,2]],"date-time":"2021-04-02T04:13:51Z","timestamp":1617336831000},"page":"586","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Quantum Retrodiction: Foundations and Controversies"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0733-4524","authenticated-orcid":false,"given":"Stephen M.","family":"Barnett","sequence":"first","affiliation":[{"name":"School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8573-1675","authenticated-orcid":false,"given":"John","family":"Jeffers","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David T.","family":"Pegg","sequence":"additional","affiliation":[{"name":"Centre for Quantum Dynamics, School of Science, Griffith University, Nathan 4111, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1103\/RevModPhys.27.179","article-title":"Symmetry of Physical Laws. 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