Design of coherent quantum observers for linear quantum systems

Vuglar, Shanon L.; Amini, Hadis

doi:10.1088/1367-2630/16/12/125005

Cited by 8 publications

(8 citation statements)

References 21 publications

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“…In 'Rapid steady-state convergence for quantum systems using time-delayed feedback control' [5], Grimsmo et al explore the use of time-delayed feedback in coherent feedback control without measurement and show that this may be used to speed-up the establishment of steady states. Vuglar and Amini address the general issue of a coherent monitoring of a quantum system in 'Design of coherent quantum observers for linear quantum systems' [6], making proposals for design of quantum observers to replace classical measurementbased monitoring. Gough et al address the problem of monitoring continuous matrix product states relevant to non-classical photon fields in 'Quantum trajectories for a class of continuous matrix product input states' [7], Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.…”

Section: Advances In Theoretical Methodologymentioning

confidence: 99%

Focus on coherent control of complex quantum systems

Whaley

Milburn

2015

New J. Phys.

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The rapid growth of quantum information sciences over the past few decades has fueled a corresponding rise in high profile applications in fields such as metrology, sensors, spintronics, and attosecond dynamics, in addition to quantum information processing. Realizing this potential of today's quantum science and the novel technologies based on this requires a high degree of coherent control of quantum systems. While early efforts in systematizing methods for high fidelity quantum control focused on isolated or closed quantum systems, recent advances in experimental design, measurement and monitoring, have stimulated both need and interest in the control of complex or large scale quantum systems that may also be coupled to an interactive environment or reservoir. This focus issue brings together new theoretical and experimental work addressing the formulation and implementation of quantum control for a broad range of applications in quantum science and technology today.

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Section: Advances In Theoretical Methodologymentioning

confidence: 99%

Focus on coherent control of complex quantum systems

Whaley

Milburn

2015

New J. Phys.

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“…1, we take the quantum output signal of the plant and directly fed it into the coherent quantum observer [23,24,30]. An (MT) coherent quantum observer is another system of quantum harmonic oscillators which we engineer such that the system variables track those of the quantum plant asymptotically in the sense of mean values.…”

Section: Quantum Plants and Coherent Quantum Observersmentioning

confidence: 99%

Coherently tracking the covariance matrix of an open quantum system

2015

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Coherent feedback control of quantum systems has demonstrable advantages over measurementbased control, but so far there has been little work done on coherent estimators and more specifically coherent observers. Coherent observers are input the coherent output of a specified quantum plant, and are designed such that some subset of the observer and plant's expectation values converge in the asymptotic limit. We previously developed a class of mean tracking (MT) observers for open harmonic oscillators that only converged in mean position and momentum; Here we develop a class of covariance matrix tracking (CMT) coherent observers that track both the mean and covariance matrix of a quantum plant. We derive necessary and sufficient conditions for the existence of a CMT observer, and find there are more restrictions on a CMT observer than there are on a MT observer. We give examples where we demonstrate how to design a CMT observer and show it can be used to track properties like the entanglement of a plant. As the CMT observer provides more quantum information than a MT observer, we expect it will have greater application in future coherent feedback schemes mediated by coherent observers. Investigation of coherent quantum estimators and observers is important in the ongoing discussion of quantum measurement; As they provide estimation of a system's quantum state without explicit use of the measurement postulate in their derivation.

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“…A coherent observer is another system of quantum harmonic oscillators which we engineer such that at least the system variables track those of the quantum plant asymptotically in the sense of mean values [27], [28], [35]. In classical control theory, it is well known that if not all state variables of a linear plant are available for feedback, an observer may be needed for feedback design [8], [40].…”

Section: Observer-based Feedback Controller and The Pole-placement Te...mentioning

confidence: 99%

“…It is well established that estimating a classical linear dynamic system from a series of noisy measurements using the Kalman filter can provide improved performance over direct feedback schemes [2], [3]. Unfortunately, traditional techniques do not appear to be applicable to coherent feedback due to difficulties with quantum conditioning onto non-commutative subspaces of signals [1], [4], [5], [30], [35]. Furthermore, due to the Heisenberg uncertainty principle, there is a fundamental limit for the mean squared estimation error.…”

Section: Introductionmentioning

confidence: 99%

Pole placement design for quantum systems via coherent observers

Zhang

James

Ugrinovskii

2015

2015 54th IEEE Conference on Decision and Control (CDC)

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Abstract-We previously extended Luenberger's approach for observer design to the quantum case, and developed a class of coherent observers which tracks linear quantum stochastic systems in the sense of mean values. In light of the fact that the Luenberger observer is commonly and successfully applied in classical control, it is interesting to investigate the role of coherent observers in quantum feedback. As the first step in exploring observer-based coherent control, in this paper we study pole-placement techniques for quantum systems using coherent observers, and in such a fashion, poles of a closed-loop quantum system can be relocated at any desired locations. In comparison to classical feedback control design incorporating the Luenberger observer, here direct coupling between a quantum plant and the observer-based controller are allowed to enable a greater degree of freedom for the design of controller parameters. A separation principle is presented, and we show how to design the observer and feedback independently to be consistent with the laws of quantum mechanics. The proposed scheme is applicable to coherent feedback control of quantum systems, especially when the transient dynamic response is of interest, and this issue is illustrated in an example.

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Design of coherent quantum observers for linear quantum systems

Cited by 8 publications

References 21 publications

Focus on coherent control of complex quantum systems

Focus on coherent control of complex quantum systems

Coherently tracking the covariance matrix of an open quantum system

Pole placement design for quantum systems via coherent observers

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