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Observation of Quantum Noise Reduction in a Raman Amplifier via Quantum Correlation between Atom and Light
Jianmin Wang1, Rong Zhu1, Yue Li1
1City University of Hong Kong, Department of Physics, 83 Tat Chee Avenue, Kowloon, Hong Kong.
Physical Review Letters
|November 30, 2025
Summary
Researchers reduced quantum noise in a Raman amplifier by correlating atoms with light. This quantum noise reduction exceeded 3.5 dB, paving the way for quantum-enhanced sensors.
Area of Science:
- Quantum optics
- Atomic physics
- Quantum information science
Background:
- Amplifiers require coupling to internal degrees of freedom for energy gain, which introduces quantum noise.
- Manipulating an amplifier's internal degrees of freedom offers a pathway to manage and reduce output quantum noise.
Purpose of the Study:
- To experimentally reduce quantum noise in a Raman amplifier.
- To investigate the potential of correlated atomic states for noise reduction.
Main Methods:
- Preparing an atomic medium in a correlated state with the Stokes light field.
- Utilizing a Raman amplifier setup to observe quantum noise reduction.
- Measuring quantum correlation between the atom and light at high gain.
Main Results:
- Observed quantum noise reduction exceeding 3.5 dB in the atomic Raman amplification process.
- Demonstrated that a high-gain Raman amplifier can function as a quantum correlation measurement tool.
- Established a quantum-entangled atom-light hybrid interferometer.
Conclusions:
- Correlated atomic states can significantly reduce quantum noise in amplifiers.
- The developed scheme enables quantum-enhanced sensing applications.
- Highlights the interplay between quantum noise, correlation, and entanglement in atom-light systems.
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