Mutual information superadditivity and unitarity bounds

Abstract We derive the property of strong superadditivity of mutual information arising from the Markov property of the vacuum state in a conformal field theory and strong subadditivity of entanglement entropy. We show this inequality encodes unitarity bounds for different types of fields. These uni...

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Main Authors: Horacio Casini, Eduardo Testé, Gonzalo Torroba
Format: Article
Language:English
Published: SpringerOpen 2021-09-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP09(2021)046
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author Horacio Casini
Eduardo Testé
Gonzalo Torroba
author_facet Horacio Casini
Eduardo Testé
Gonzalo Torroba
author_sort Horacio Casini
collection DOAJ
description Abstract We derive the property of strong superadditivity of mutual information arising from the Markov property of the vacuum state in a conformal field theory and strong subadditivity of entanglement entropy. We show this inequality encodes unitarity bounds for different types of fields. These unitarity bounds are precisely the ones that saturate for free fields. This has a natural explanation in terms of the possibility of localizing algebras on null surfaces. A particular continuity property of mutual information characterizes free fields from the entropic point of view. We derive a general formula for the leading long distance term of the mutual information for regions of arbitrary shape which involves the modular flow of these regions. We obtain the general form of this leading term for two spheres with arbitrary orientations in spacetime, and for primary fields of any tensor representation. For free fields we further obtain the explicit form of the leading term for arbitrary regions with boundaries on null cones.
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spelling doaj.art-5d01be934eed4711ac95f7643096898f2022-12-21T18:46:34ZengSpringerOpenJournal of High Energy Physics1029-84792021-09-012021913810.1007/JHEP09(2021)046Mutual information superadditivity and unitarity boundsHoracio Casini0Eduardo Testé1Gonzalo Torroba2Centro Atómico Bariloche and CONICETDepartment of Physics, University of CaliforniaCentro Atómico Bariloche and CONICETAbstract We derive the property of strong superadditivity of mutual information arising from the Markov property of the vacuum state in a conformal field theory and strong subadditivity of entanglement entropy. We show this inequality encodes unitarity bounds for different types of fields. These unitarity bounds are precisely the ones that saturate for free fields. This has a natural explanation in terms of the possibility of localizing algebras on null surfaces. A particular continuity property of mutual information characterizes free fields from the entropic point of view. We derive a general formula for the leading long distance term of the mutual information for regions of arbitrary shape which involves the modular flow of these regions. We obtain the general form of this leading term for two spheres with arbitrary orientations in spacetime, and for primary fields of any tensor representation. For free fields we further obtain the explicit form of the leading term for arbitrary regions with boundaries on null cones.https://doi.org/10.1007/JHEP09(2021)046Conformal Field TheoryRenormalization Group
spellingShingle Horacio Casini
Eduardo Testé
Gonzalo Torroba
Mutual information superadditivity and unitarity bounds
Journal of High Energy Physics
Conformal Field Theory
Renormalization Group
title Mutual information superadditivity and unitarity bounds
title_full Mutual information superadditivity and unitarity bounds
title_fullStr Mutual information superadditivity and unitarity bounds
title_full_unstemmed Mutual information superadditivity and unitarity bounds
title_short Mutual information superadditivity and unitarity bounds
title_sort mutual information superadditivity and unitarity bounds
topic Conformal Field Theory
Renormalization Group
url https://doi.org/10.1007/JHEP09(2021)046
work_keys_str_mv AT horaciocasini mutualinformationsuperadditivityandunitaritybounds
AT eduardoteste mutualinformationsuperadditivityandunitaritybounds
AT gonzalotorroba mutualinformationsuperadditivityandunitaritybounds