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Updated: Oct 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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Generating Greenberger-Horne-Zeilinger states with squeezing and postselection.
Byron Alexander1, John J Bollinger2, Hermann Uys1,3
1Department of Physics, Stellenbosch University, Stellenbosch Central 7600, Stellenbosch, South Africa.
Physical Review. A
|November 19, 2021
Summary
This study introduces quantum measurement as a novel tool for quantum state preparation, significantly reducing preparation time for highly entangled Greenberger-Horne-Zeilinger (GHZ) states.
Area of Science:
- Quantum Information Science
- Quantum Optics
- Quantum Computing
Background:
- Standard quantum state preparation often combines dissipative initialization with unitary evolution.
- Efficient preparation of highly entangled multipartite states is crucial for quantum technologies.
Purpose of the Study:
- To demonstrate the utility of quantum measurement as an additional tool for quantum state preparation.
- To generate highly entangled multipartite states, termed projected squeezed (PS) states.
- To optimize PS states for overlap fidelity with Greenberger-Horne-Zeilinger (GHZ) states.
Main Methods:
- Utilizing a control sequence involving rotation, spin squeezing (one-axis twisting), quantum measurement, and postselection.
- Starting from a pure, separable multipartite state.
- Employing an optimization method to maximize fidelity with GHZ states.
Main Results:
- Successfully generated projected squeezed (PS) states, a type of highly entangled multipartite state.
- Identified optimal parameters for PS states to achieve high overlap fidelity with GHZ states.
- Achieved a notable decrease in state preparation time for GHZ states via postselection compared to methods using only unitary evolution.
Conclusions:
- Quantum measurement offers an effective enhancement to quantum state preparation protocols.
- The proposed method provides a faster route to preparing GHZ states when postselection is successful.
- This approach advances the creation of complex entangled states for quantum information processing.
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