Quantum estimation of detection efficiency with no-knowledge quantum feedback

Xie, Dong; Xu, Chuanju

doi:10.1088/1674-1056/27/6/060303

Cited by 5 publications

(4 citation statements)

References 35 publications

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“…There are two measurement strategies: one is the simultaneous estimation of the two temperatures, the other is the individual estimation of the two temperatures. A lot of works [29][30][31][32][33][34][35][36][37][38] clearly showed that the simultaneous estimation can be more precise than the individual estimation given by the same resource. And then we're going to look at whether that's true in the diffraction case.…”

Section: Estimating Two Different Temperaturesmentioning

confidence: 99%

Quantum thermometry in diffraction-limited systems

Xie¹,

Xu²,

Wang³

2022

Preprint

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We investigate the ultimate quantum limit of resolving the temperatures of two thermal sources affected by the diffraction. More quantum Fisher information can be obtained with the priori information than that without the priori information. We carefully consider two strategies: the simultaneous estimation and the individual estimation. The simultaneous estimation of two temperatures is proved to satisfy the saturation condition of quantum Cramér bound and performs better than the individual estimation in the case of small degree of diffraction given the same resources. However, in the case of high degree of diffraction, the individual estimation performs better. In particular, at the maximum diffraction, the simultaneous estimation can not get any information, which is supported by a practical measurement, while the individual estimation can still get the information. In addition, we find that for the individual estimation, a practical and feasible estimation strategy by using the full Hermite-Gauss basis can saturate the quantum Cramér bound without being affected by the attenuation factor at the maximum diffraction.

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Section: Estimating Two Different Temperaturesmentioning

confidence: 99%

Quantum thermometry in diffraction-limited systems

Xie¹,

Xu²,

Wang³

2022

Preprint

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“…If multiple observation operators need to be measured at the same time, the above equation can be extended to [45] dρ(t) dt…”

Section: Investigation Modelmentioning

confidence: 99%

Optimal parameter estimation of open quantum systems*

2020

Chinese Phys. B

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In quantum information technologies, quantum weak measurement is beneficial for protecting coherence of systems. In order to further improve the protection effect of quantum weak measurement on coherence, we propose an optimization scheme of quantum Fisher information (QFI) protection in an open quantum system by combing no-knowledge quantum feedback control with quantum weak measurement. On the basis of solving the dynamic equations of a stochastic two-level quantum system under feedback control, we compare the effects of different feedback Hamiltonians on QFI and find that via no-knowledge quantum feedback, the observation operator σx (or σx and σz ) can protect QFI for a long time. Namely, no-knowledge quantum feedback can improve the estimation precision of feedback coefficient as well as that of detection coefficient.

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“…Once the backaction is perfectly reversed for all individual noise realizations, the decoherence on the system's average dynamics can be completely suppressed. The protocol can be applied in the case where the system-bath coupling operators are Hermitian, but can also be adapted for non-Hermitian coupling by adding extra conjugate channels (e.g., using gain and loss channels for bosonic baths) and mixing output records using beam splitters [15,18,19].…”

Section: Introductionmentioning

confidence: 99%