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Joint Estimation of a Two-Phase Spin Rotation beyond Classical Limit.
Jiahao Cao1,2, Xinwei Li1,3, Tianwei Mao2
1Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
Physical Review Letters
|July 31, 2025
Summary
This study demonstrates quantum-enhanced multiparameter estimation for simultaneous spin rotations. Using spin-nematic squeezing in atomic Bose-Einstein condensates, researchers achieved precision beyond classical limits for multiple parameters.
Area of Science:
- Quantum metrology
- Atomic physics
- Quantum sensing
Background:
- Quantum metrology leverages entanglement to improve measurement precision, traditionally focusing on single parameter estimation.
- Many applications require simultaneous estimation of multiple parameters, where joint estimation may offer further precision advantages.
- Existing quantum metrology techniques have limitations in simultaneously estimating noncommuting parameters.
Purpose of the Study:
- To demonstrate quantum-enhanced multiparameter estimation for simultaneous spin rotations around orthogonal axes.
- To utilize spin-nematic squeezing in atomic Bose-Einstein condensates for enhanced precision in joint parameter estimation.
- To explore the application of entangled massive particles in multiparameter quantum sensing.
Main Methods:
- Employing spin-nematic squeezing in an atomic Bose-Einstein condensate.
- Utilizing F=2 ground hyperfine manifold states coupled to nematic-squeezed F=1 states as an auxiliary field.
- Applying a sequence of microwave (MW) pulses for manipulation and measurement.
- Simultaneously measuring multiple spin-1 observables.
Main Results:
- Achieved quantum-enhanced estimation of simultaneous spin rotations around two orthogonal axes.
- Demonstrated an enhancement factor of 3.3 to 6.3 decibels (dB) beyond the classical limit.
- Successfully performed multiparameter estimation using entangled massive particles for the first time.
- Showcased the utility of two-mode squeezed vacuum states in sensing noncommuting spin rotations.
Conclusions:
- This work represents the first quantum-enhanced multiparameter estimation using entangled massive particles.
- The developed techniques and protocols are applicable to quantum-enhanced sensing of noncommuting spin rotations.
- The study highlights the potential of spin-nematic squeezing for advanced quantum metrology applications.
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