Chinese Academy of Sciences gains important progress in quantum precision measurement
2018-04-19 13:00:19
Research and Development of China Instrument Network Instrumentation The Key Laboratory of Quantum Information of the Chinese Academy of Sciences, led by Academician Guo Guangcan from the University of Science and Technology of China, has made important progress in the direction of quantum precision measurement. Li Chuanfeng and Tang Jianshun of the laboratory have combined weak measurement technology with energy recycling technology. For the first time, energy-cycle weak measurements that exceed the limits of classical measurement accuracy have been realized, demonstrating the significant advantages of quantum-weak measurement techniques in the field of high-precision measurement. The research results were published on the November 29th in the international authoritative journal Physical Review Letters.
The concept of quantum weak measurement was first proposed by the famous physicists Aharonov, Albert, and Vaidman in 1988 and has been widely used in various types of high-precision measurement. Now we can use quantum weak measurement technology to amplify tens of thousands of weak signals. However, the accuracy of quantum weak measurement has been controversial. Take the optical experiment as an example. On the one hand, by setting the proper pre-selection state and post-selection state of the photon, the quantum weak measurement can realize the amplification of weak signals and improve the measurement responsivity; on the other hand, the post-selection process in weak measurement leads to only A small amount of photons are used, and all other photons are discarded. With the decrease of the number of useful photons, the shot noise caused by the quantum fluctuation will cause the measurement accuracy (the ratio of signal and noise) to decrease. Whether the accuracy of quantum weak measurement can surpass the limit of classical measurement accuracy has become a research hotspot in recent years.
Li Chuanfeng's research group experimentally used optical cavity technology to return the photons that were discarded from the weak measurement back to the measuring device to realize the recycling of the measured photons, thereby skillfully combining the energy cycle technology with the weak measurement technology. Under the condition of keeping the detection device unchanged, they used the classic measurement scheme, the standard quantum weak measurement scheme, and the energy circulation type quantum weak measurement scheme to accurately measure the small deflection angle of the same beam. The experimental results show that the standard weak measurement accuracy can't really break the classical measurement accuracy limit, while the energy cycle type quantum weak measurement can increase the measurement signal strength to 2.4 times the standard weak measurement signal strength while the measurement accuracy can reach the classic measurement. 1.5 times the accuracy limit.
The results of this study show that when the measurement probe (ie the photon in this experiment) is recycled, the quantum weak measurement can achieve higher measurement accuracy than the classical measurement solution. This work provides a new direction for the development of quantum computing and precision measurement technology.
The first author of the article is Wang Kai, a doctoral student. The work was funded by the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the Collaborative Innovation Center for Quantum Information and Quantum Science.
(Original title: China University of Science and Technology for the first time realized energy cycle quantum high-precision measurement)
The concept of quantum weak measurement was first proposed by the famous physicists Aharonov, Albert, and Vaidman in 1988 and has been widely used in various types of high-precision measurement. Now we can use quantum weak measurement technology to amplify tens of thousands of weak signals. However, the accuracy of quantum weak measurement has been controversial. Take the optical experiment as an example. On the one hand, by setting the proper pre-selection state and post-selection state of the photon, the quantum weak measurement can realize the amplification of weak signals and improve the measurement responsivity; on the other hand, the post-selection process in weak measurement leads to only A small amount of photons are used, and all other photons are discarded. With the decrease of the number of useful photons, the shot noise caused by the quantum fluctuation will cause the measurement accuracy (the ratio of signal and noise) to decrease. Whether the accuracy of quantum weak measurement can surpass the limit of classical measurement accuracy has become a research hotspot in recent years.
Li Chuanfeng's research group experimentally used optical cavity technology to return the photons that were discarded from the weak measurement back to the measuring device to realize the recycling of the measured photons, thereby skillfully combining the energy cycle technology with the weak measurement technology. Under the condition of keeping the detection device unchanged, they used the classic measurement scheme, the standard quantum weak measurement scheme, and the energy circulation type quantum weak measurement scheme to accurately measure the small deflection angle of the same beam. The experimental results show that the standard weak measurement accuracy can't really break the classical measurement accuracy limit, while the energy cycle type quantum weak measurement can increase the measurement signal strength to 2.4 times the standard weak measurement signal strength while the measurement accuracy can reach the classic measurement. 1.5 times the accuracy limit.
The results of this study show that when the measurement probe (ie the photon in this experiment) is recycled, the quantum weak measurement can achieve higher measurement accuracy than the classical measurement solution. This work provides a new direction for the development of quantum computing and precision measurement technology.
The first author of the article is Wang Kai, a doctoral student. The work was funded by the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the Collaborative Innovation Center for Quantum Information and Quantum Science.
(Original title: China University of Science and Technology for the first time realized energy cycle quantum high-precision measurement)