Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information

Abstract In this paper, we investigate the dynamics of a non-Hermitian Su-Schrieffer-Heeger model that arises out of the no-click limit of a monitored SSH model in the Krylov space. We find that the saturation timescale of the complexity associated with the spread of the state in the Krylov subspace...

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Main Authors: Nilachal Chakrabarti, Neha Nirbhan, Arpan Bhattacharyya
Format: Article
Language:English
Published: SpringerOpen 2025-07-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP07(2025)203
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author Nilachal Chakrabarti
Neha Nirbhan
Arpan Bhattacharyya
author_facet Nilachal Chakrabarti
Neha Nirbhan
Arpan Bhattacharyya
author_sort Nilachal Chakrabarti
collection DOAJ
description Abstract In this paper, we investigate the dynamics of a non-Hermitian Su-Schrieffer-Heeger model that arises out of the no-click limit of a monitored SSH model in the Krylov space. We find that the saturation timescale of the complexity associated with the spread of the state in the Krylov subspace increases with the measurement rate, and late time behaviour differs across the PT symmetry transition point. Furthermore, extending the notion of this complexity for subsystems in Krylov space, we find that the scaling of its late time value with subsystem size shows a discontinuous jump across the PT transition point, indicating that it can be used as a suitable order parameter for such transition but not for the measurement-induced transition. Finally, we show that a generalized measure in the Krylov subspace, which contains information about the correlation landscape, such as Quantum Fisher information, which also possesses some structural similarity with the complexity functional, can be a promising probe of the measurement-induced phase.
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spelling doaj-art-4152feb3aeb44dbb879fd44b5f86dcca2025-08-20T03:45:40ZengSpringerOpenJournal of High Energy Physics1029-84792025-07-012025714010.1007/JHEP07(2025)203Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher informationNilachal Chakrabarti0Neha Nirbhan1Arpan Bhattacharyya2Department of Physics, Indian Institute of Technology GandhinagarDepartment of Physics, Indian Institute of Technology GandhinagarDepartment of Physics, Indian Institute of Technology GandhinagarAbstract In this paper, we investigate the dynamics of a non-Hermitian Su-Schrieffer-Heeger model that arises out of the no-click limit of a monitored SSH model in the Krylov space. We find that the saturation timescale of the complexity associated with the spread of the state in the Krylov subspace increases with the measurement rate, and late time behaviour differs across the PT symmetry transition point. Furthermore, extending the notion of this complexity for subsystems in Krylov space, we find that the scaling of its late time value with subsystem size shows a discontinuous jump across the PT transition point, indicating that it can be used as a suitable order parameter for such transition but not for the measurement-induced transition. Finally, we show that a generalized measure in the Krylov subspace, which contains information about the correlation landscape, such as Quantum Fisher information, which also possesses some structural similarity with the complexity functional, can be a promising probe of the measurement-induced phase.https://doi.org/10.1007/JHEP07(2025)203Holography and Condensed Matter Physics (AdS/CMT)Quantum Dissipative SystemsStochastic Processes
spellingShingle Nilachal Chakrabarti
Neha Nirbhan
Arpan Bhattacharyya
Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information
Journal of High Energy Physics
Holography and Condensed Matter Physics (AdS/CMT)
Quantum Dissipative Systems
Stochastic Processes
title Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information
title_full Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information
title_fullStr Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information
title_full_unstemmed Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information
title_short Dynamics of monitored SSH model in Krylov space: from complexity to quantum Fisher information
title_sort dynamics of monitored ssh model in krylov space from complexity to quantum fisher information
topic Holography and Condensed Matter Physics (AdS/CMT)
Quantum Dissipative Systems
Stochastic Processes
url https://doi.org/10.1007/JHEP07(2025)203
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AT arpanbhattacharyya dynamicsofmonitoredsshmodelinkrylovspacefromcomplexitytoquantumfisherinformation