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Quantum Precision Measurement of Noise Adaptation in the Experiment of the University of Science and Technology
[ Instrument Network Instrument Development ] Guo Guangcan, a member of the Chinese Academy of Sciences and a professor at the University of Science and Technology of China, made new progress in quantum coherence and quantum precision measurement research. The team Li Chuanfeng and Huang Yunfeng and the British collaborators experimentally verified the adaptability of the entangled state coherence to the lateral noise in the linear optical system, and further verified that the quantum measurement accuracy of the entangled probe in the lateral noise can still exceed the standard. Quantum limit. The research results were published on the International Physics Journal "Physical Review Letter" on November 1.
Quantum information technology realizes the secure transmission and storage of information, efficient acquisition and operation through manipulation of quantum states. However, quantum systems inevitably interact with the environment to introduce noise, which leads to the very fragile quantum state. How to resist noise is one of the core issues of current scalable quantum information technology. Active feedback and quantum error correction are promising solutions, but excessive resource consumption makes them difficult to implement at present. Another efficient and convenient way is passive noise control, which can be achieved by clever use of the adaptability of quantum states to specific noises.
Li Chuanfeng and Huang Yunfeng et al. studied the quantum coherence of entangled states and the adaptability of precision measurements to lateral noise (noise and perpendicular to the working direction of the probe) using a highly efficient and controllable linear optical system. The research team first verified the phenomenon of the coherence of the four-photon GHZ entangled state under lateral noise, and also observed that the quantum Fisher information remained unchanged when the GHZ entangled state evolved in the noise, which means that it is applied to the parameter estimation. The measurement accuracy will not decay with increasing noise. The research team further considered the more practical situation, and applied noise and signal to the probe at the same time. The results show that even if the noise intensity is the same as the signal, the multiphoton GHZ entangled probe prepared in the experiment can surpass when the photon number reaches 6. The standard quantum limit (the limit that classical physical systems can achieve) demonstrates the superiority of noise-adapted quantum precision measurement schemes. Of course, the experimental results also confirm that the GHZ entangled probe will not exhibit any quantum advantage in the case of parallel noise.
This work demonstrates the feasibility of passive noise control and is an important step in the study of anti-noise quantum precision measurement, helping to design a more efficient anti-noise solution.
The first author of the thesis is Zhang Chao, a special associate researcher at the Key Laboratory of Quantum Information of the Chinese Academy of Sciences. The research was supported by the Ministry of Science and Technology, the National Fund Committee, the Chinese Academy of Sciences, Anhui Province, and the Center for Collaborative Innovation in Quantum Information and Quantum Technology.