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Updated: Jul 12, 2025
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Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
Published on: May 30, 2014
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Optimal Estimation of Quantum Coherence by Bell State Measurement: A Case Study
Yuan Yuan1, Xufeng Huang1, Yueping Niu1,2,3
1School of Physics, East China University of Science and Technology, Shanghai 200237, China.
Entropy (Basel, Switzerland)
|October 28, 2023
Summary
Bell state measurement efficiently estimates quantum coherence without complex procedures. This optimal measurement approach is crucial for advancing quantum information technologies and quantum metrology.
Area of Science:
- Quantum Information Science
- Quantum Mechanics
Background:
- Quantum coherence is a key resource in quantum mechanics, vital for quantum algorithms, computation, key distribution, and metrology.
- Efficient tools for estimating quantum coherence are essential for developing quantum information technologies.
Purpose of the Study:
- To analyze the performance of Bell state measurement for estimating quantum coherence in a qubit system.
- To evaluate Bell state measurement from the perspectives of semiparametric and single-parameter estimation.
Main Methods:
- Utilizing Bell state measurement as a two-copy collective measurement for direct coherence estimation.
- Applying semiparametric estimation and single-parameter estimation frameworks.
- Analyzing Fisher information and the quantum limit of estimation.
Main Results:
- Bell state measurement directly estimates quantum coherence without requiring optimization or complex calculations.
- Numerical results demonstrate that Bell state measurement is the optimal measurement for frequently-used coherence quantifiers.
- The optimality is confirmed within the quantum limit of semiparametric estimation.
Conclusions:
- Bell state measurement offers an efficient and optimal method for quantifying quantum coherence.
- This technique simplifies experimental procedures for coherence estimation, advancing quantum information processing.
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