A universal approach to Krylov state and operator complexities

We present a general framework in which both Krylov state and operator complexities can be put on the same footing. In our formalism, the Krylov complexity is defined in terms of the density matrix of the associated state which, for the operator complexity, lives on a doubled Hilbert space obtained...

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Main Author: Mohsen Alishahiha, Souvik Banerjee
Format: Article
Language:English
Published: SciPost 2023-09-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.15.3.080
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author Mohsen Alishahiha, Souvik Banerjee
author_facet Mohsen Alishahiha, Souvik Banerjee
author_sort Mohsen Alishahiha, Souvik Banerjee
collection DOAJ
description We present a general framework in which both Krylov state and operator complexities can be put on the same footing. In our formalism, the Krylov complexity is defined in terms of the density matrix of the associated state which, for the operator complexity, lives on a doubled Hilbert space obtained through the channel-state map. This unified definition of complexity in terms of the density matrices enables us to extend the notion of Krylov complexity, to subregion or mixed state complexities and also naturally to the Krylov mutual complexity. We show that this framework also encompasses nicely the holographic notions of complexity.
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spelling doaj.art-1459123a5d244fde98924e7d89fac2202023-09-06T10:20:08ZengSciPostSciPost Physics2542-46532023-09-0115308010.21468/SciPostPhys.15.3.080A universal approach to Krylov state and operator complexitiesMohsen Alishahiha, Souvik BanerjeeWe present a general framework in which both Krylov state and operator complexities can be put on the same footing. In our formalism, the Krylov complexity is defined in terms of the density matrix of the associated state which, for the operator complexity, lives on a doubled Hilbert space obtained through the channel-state map. This unified definition of complexity in terms of the density matrices enables us to extend the notion of Krylov complexity, to subregion or mixed state complexities and also naturally to the Krylov mutual complexity. We show that this framework also encompasses nicely the holographic notions of complexity.https://scipost.org/SciPostPhys.15.3.080
spellingShingle Mohsen Alishahiha, Souvik Banerjee
A universal approach to Krylov state and operator complexities
SciPost Physics
title A universal approach to Krylov state and operator complexities
title_full A universal approach to Krylov state and operator complexities
title_fullStr A universal approach to Krylov state and operator complexities
title_full_unstemmed A universal approach to Krylov state and operator complexities
title_short A universal approach to Krylov state and operator complexities
title_sort universal approach to krylov state and operator complexities
url https://scipost.org/SciPostPhys.15.3.080
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