Identification of single-input–single-output quantum linear systems

The purpose of this paper is to investigate system identification for single-input–single-output general (active or passive) quantum linear systems. For a given input we address the following questions: (1) Which parameters can be identified by measuring the output? (2) How can we construct a system...

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Main Authors: Levitt, Matthew, Guţă, Mădălin
Format: Article
Published: American Physical Society 2017
Online Access:https://eprints.nottingham.ac.uk/41083/
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author Levitt, Matthew
Guţă, Mădălin
author_facet Levitt, Matthew
Guţă, Mădălin
author_sort Levitt, Matthew
building Nottingham Research Data Repository
collection Online Access
description The purpose of this paper is to investigate system identification for single-input–single-output general (active or passive) quantum linear systems. For a given input we address the following questions: (1) Which parameters can be identified by measuring the output? (2) How can we construct a system realization from sufficient input-output data? We show that for time-dependent inputs, the systems which cannot be distinguished are related by symplectic transformations acting on the space of system modes. This complements a previous result of Guţă and Yamamoto [IEEE Trans. Autom. Control 61, 921 (2016)] for passive linear systems. In the regime of stationary quantum noise input, the output is completely determined by the power spectrum. We define the notion of global minimality for a given power spectrum, and characterize globally minimal systems as those with a fully mixed stationary state. We show that in the case of systems with a cascade realization, the power spectrum completely fixes the transfer function, so the system can be identified up to a symplectic transformation. We give a method for constructing a globally minimal subsystem direct from the power spectrum. Restricting to passive systems the analysis simplifies so that identifiability may be completely understood from the eigenvalues of a particular system matrix.
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spelling nottingham-410832020-05-04T18:38:45Z https://eprints.nottingham.ac.uk/41083/ Identification of single-input–single-output quantum linear systems Levitt, Matthew Guţă, Mădălin The purpose of this paper is to investigate system identification for single-input–single-output general (active or passive) quantum linear systems. For a given input we address the following questions: (1) Which parameters can be identified by measuring the output? (2) How can we construct a system realization from sufficient input-output data? We show that for time-dependent inputs, the systems which cannot be distinguished are related by symplectic transformations acting on the space of system modes. This complements a previous result of Guţă and Yamamoto [IEEE Trans. Autom. Control 61, 921 (2016)] for passive linear systems. In the regime of stationary quantum noise input, the output is completely determined by the power spectrum. We define the notion of global minimality for a given power spectrum, and characterize globally minimal systems as those with a fully mixed stationary state. We show that in the case of systems with a cascade realization, the power spectrum completely fixes the transfer function, so the system can be identified up to a symplectic transformation. We give a method for constructing a globally minimal subsystem direct from the power spectrum. Restricting to passive systems the analysis simplifies so that identifiability may be completely understood from the eigenvalues of a particular system matrix. American Physical Society 2017-03-22 Article PeerReviewed Levitt, Matthew and Guţă, Mădălin (2017) Identification of single-input–single-output quantum linear systems. Physical Review A, 95 (3). 033825/1-033825/15. ISSN 2469-9934 https://journals.aps.org/pra/abstract/10.1103/PhysRevA.95.033825 doi:10.1103/PhysRevA.95.033825 doi:10.1103/PhysRevA.95.033825
spellingShingle Levitt, Matthew
Guţă, Mădălin
Identification of single-input–single-output quantum linear systems
title Identification of single-input–single-output quantum linear systems
title_full Identification of single-input–single-output quantum linear systems
title_fullStr Identification of single-input–single-output quantum linear systems
title_full_unstemmed Identification of single-input–single-output quantum linear systems
title_short Identification of single-input–single-output quantum linear systems
title_sort identification of single-input–single-output quantum linear systems
url https://eprints.nottingham.ac.uk/41083/
https://eprints.nottingham.ac.uk/41083/
https://eprints.nottingham.ac.uk/41083/