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Mixed state discrimination using optimal control
B L Higgins1, B M Booth, A C Doherty
1Centre for Quantum Dynamics, Griffith University, Brisbane, 4111, Australia.
Physical Review Letters
|April 7, 2010
Summary
We developed new quantum measurement strategies to better distinguish between similar quantum states, even with noise. Our optimal local strategy improves performance compared to simpler methods when dealing with noisy quantum information.
Area of Science:
- Quantum information science
- Quantum measurement theory
- Quantum state discrimination
Background:
- Distinguishing nonorthogonal quantum states is crucial for quantum information processing.
- Real-world quantum systems are susceptible to noise, degrading performance.
- Existing measurement schemes may not be robust to noise.
Purpose of the Study:
- To develop and experimentally validate optimal local measurement strategies for discriminating noisy, nonorthogonal quantum states.
- To compare the performance of various local measurement schemes under depolarizing noise.
Main Methods:
- Theoretical derivation using optimal control theory.
- Experimental implementation of local measurement schemes.
- Testing with pure and depolarizing-noise-mixed states.
Main Results:
- Noise degrades the performance of previously optimal schemes.
- A globally optimal local measurement strategy was derived and experimentally confirmed.
- The optimal strategy significantly outperforms other local schemes, especially under higher noise levels.
Conclusions:
- Optimal local measurement strategies are essential for robust quantum state discrimination.
- The derived strategy offers a significant improvement for practical quantum information tasks.
- This work provides a pathway for enhanced quantum sensing and communication.
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