A type I approximation of the crossed product

Abstract I show that an analog of the crossed product construction that takes type 𝐼𝐼𝐼1 algebras to type 𝐼𝐼 algebras exists also in the type 𝐼 case. This is particularly natural when the local algebra is a non-trivial direct sum of type 𝐼 factors. Concretely, I rewrite the usual type 𝐼 trace in a di...

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Main Author: Ronak M. Soni
Format: Article
Language:English
Published: SpringerOpen 2024-01-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP01(2024)123
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author Ronak M. Soni
author_facet Ronak M. Soni
author_sort Ronak M. Soni
collection DOAJ
description Abstract I show that an analog of the crossed product construction that takes type 𝐼𝐼𝐼1 algebras to type 𝐼𝐼 algebras exists also in the type 𝐼 case. This is particularly natural when the local algebra is a non-trivial direct sum of type 𝐼 factors. Concretely, I rewrite the usual type 𝐼 trace in a different way and renormalise it. This new renormalised trace stays well-defined even when each factor is taken to be type 𝐼𝐼𝐼. I am able to recover both type 𝐼𝐼 ∞ as well as type 𝐼𝐼1 algebras by imposing different constraints on the central operator in the code. An example of this structure appears in holographic quantum error-correcting codes; the central operator is then the area operator.
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spelling doaj.art-a0c78431a22b4bfcb53faec82bff97852024-01-28T12:25:10ZengSpringerOpenJournal of High Energy Physics1029-84792024-01-012024111910.1007/JHEP01(2024)123A type I approximation of the crossed productRonak M. Soni0Department of Applied Mathematics and Theoretical Physics, University of CambridgeAbstract I show that an analog of the crossed product construction that takes type 𝐼𝐼𝐼1 algebras to type 𝐼𝐼 algebras exists also in the type 𝐼 case. This is particularly natural when the local algebra is a non-trivial direct sum of type 𝐼 factors. Concretely, I rewrite the usual type 𝐼 trace in a different way and renormalise it. This new renormalised trace stays well-defined even when each factor is taken to be type 𝐼𝐼𝐼. I am able to recover both type 𝐼𝐼 ∞ as well as type 𝐼𝐼1 algebras by imposing different constraints on the central operator in the code. An example of this structure appears in holographic quantum error-correcting codes; the central operator is then the area operator.https://doi.org/10.1007/JHEP01(2024)1231/𝑁 ExpansionAdS-CFT CorrespondenceGauge-Gravity Correspondence
spellingShingle Ronak M. Soni
A type I approximation of the crossed product
Journal of High Energy Physics
1/𝑁 Expansion
AdS-CFT Correspondence
Gauge-Gravity Correspondence
title A type I approximation of the crossed product
title_full A type I approximation of the crossed product
title_fullStr A type I approximation of the crossed product
title_full_unstemmed A type I approximation of the crossed product
title_short A type I approximation of the crossed product
title_sort type i approximation of the crossed product
topic 1/𝑁 Expansion
AdS-CFT Correspondence
Gauge-Gravity Correspondence
url https://doi.org/10.1007/JHEP01(2024)123
work_keys_str_mv AT ronakmsoni atypeiapproximationofthecrossedproduct
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