Quantum Noise Protection via Weak Measurement for Quantum Mixed States

Harraz, Sajede; Cong, Shuang; Shuang, Feng

doi:10.1109/ddcls.2018.8515903

Cited by 7 publications

(7 citation statements)

References 9 publications

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“…As it has been proved in [30], to calculate the QFI of phase φ 0 for density matrix with the structure of Eq. ( 6), Eq.…”

Section: Average Total Qfimentioning

confidence: 99%

“…( 5), which is GHZ state when γ = π/2 and is generalized GHZ state (GGHZ) state when γ = π/2. To show the effectiveness of our scheme, we give the performance comparison with WMPPF scheme proposed in [30].…”

Section: Qffcr Performances For Protection Of N-qubit Ghz State In Adcmentioning

confidence: 99%

“…For comparison, we discuss another scheme that uses weak-measurement-based pre-and post-flips (WMPPF) [30] and demonstrate by the simulation results that our scheme has much better performance. In WMPPF scheme the state is measured by WM operators before the noise channel, and the flips are applied according to the result of the WM to make the state almost immune to the effects of the noise.…”

Section: Introductionmentioning

confidence: 99%

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Quantum fisher information protection of N-qubit Greenberger-Horne-Zeilinger state from decoherence

Harraz¹,

Cong²,

Zhang³

et al. 2021

Preprint

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In this paper we study the protection of N -qubit Greenberger-Horne-Zeilinger (GHZ) state and generalized N -qubit GHZ states in amplitude damping channel by means of quantum weak measurement and flip operations. We derive the explicit formulas of the performances of the protection scheme: average fidelity, average probability and the average quantum fisher information (QFI). Moreover, the analytical results for maximizing the average fidelity and probability are obtained. We show that our scheme can effectively protect the average QFI of phase for GHZ states and generalized GHZ states. The proposed scheme has the merit of protecting GHZ state and the QFI of phase against heavy amplitude damping noise. Further we show that for some generalize GHZ state, the proposed scheme can protect the state with probability one and fidelity more than 99%.

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“…As it has been proved in [30], to calculate the QFI of phase φ 0 for density matrix with the structure of Eq. ( 6), Eq.…”

Section: Average Total Qfimentioning

confidence: 99%

Section: Qffcr Performances For Protection Of N-qubit Ghz State In Adcmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantum fisher information protection of N-qubit Greenberger-Horne-Zeilinger state from decoherence

Harraz¹,

Cong²,

Zhang³

et al. 2021

Preprint

Self Cite

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show abstract

“…Most protection schemes use rotation as control operation. The unitary rotations along different axis of the Bloch sphere are defined as (13) where η is the rotation angle in the range 0 ≤ η ≤ π 2, R x (±η) represents the rotation along x-axis, R y (±η) along y-axis and R z (±η) along z-axis [46].…”

Section: The Measurement and Control Operatorsmentioning

confidence: 99%

Comparison of quantum state protection against decoherence via weak measurement, a survey

Harraz¹,

Cong²,

Nieto³

2021

Preprint

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One of the crucial tasks in quantum systems is to reduce the effects of decoherence due to the unavoidable interactions between a system and its environment. Many protection schemes have been proposed recently, among them the weak measurement quantum measurement reversal (WMQMR), weak measurementbased quantum feedback control (QFBC) and quantum feed-forward control (QFFC) are reviewed in this paper. By considering weak measurement, the aim is to find a balance between information gain and disturbance of the system caused by the measurement. We classify different types of measurement and give the definition of noise sources and their effects on the state of the system. Finally, we compare and analyze the performance of the discussed protection schemes for different noise sources by numerical simulations.

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“…When the projective or strong measurements are acted, the state of the system will collapse to its eigenstates, thus one needs to reprepare the ensemble and measurement apparatus at each step [18]. The weak measurements offer a trade-off between information gain and the disturbance of the system [19]. Since weak measurement is not completely destructive, continuous measurements are applicable with weak measurements [20].…”

Section: Introductionmentioning

confidence: 99%

Online quantum state tomography of N-qubit via continuous weak measurement and compressed sensing

Harraz

Cong

2020

Int. J. Quantum Inform.

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In this paper, we propose an online state tomography method for [Formula: see text]-qubit quantum system based on the continuous weak measurement and compressed sensing (CS). The quantum system is described by stochastic master equation. The continuous weak measurement operators for the [Formula: see text]-qubit quantum system, which are indirectly acted on the quantum system, are derived according to the measurement operator results of two-level quantum system. The online time-varying measurement operators are obtained by means of the dynamic evolution equation of the system. The quantum state is online estimated by solving the optimization problem of minimizing the two-norm with the positive definite constraints of density matrix, and we use the nonnegative least squares algorithm to solve the optimization problem. CS theory is used to reduce the number of the measurements in the process of online state estimation. In the numerical experiments, we study the effects of external control field, measurement rate and the different numbers of qubits on the performance in the proposed method. The minimum required numbers of measurements for 2, 3, 4 and 5 qubits are found. The normalized distance and fidelity of our proposed method can achieve satisfying accuracy with small number of measurements.

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Quantum Noise Protection via Weak Measurement for Quantum Mixed States

Cited by 7 publications

References 9 publications

Quantum fisher information protection of N-qubit Greenberger-Horne-Zeilinger state from decoherence

Quantum fisher information protection of N-qubit Greenberger-Horne-Zeilinger state from decoherence

Comparison of quantum state protection against decoherence via weak measurement, a survey

Online quantum state tomography of N-qubit via continuous weak measurement and compressed sensing

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