China University of Science and Technology for the first time experimental verification of six-photon GHZ nonlocal
CAS Key Laboratory of Quantum Information, led by Academician Guo Guangcan, made important progress in multiphoton nonlocal research. The lab Li Chuanfeng and Huang Yunfeng successfully prepared the world's highest fidelity six-photon Greenberger-Horne-Zeilinger (GHZ) state and verified for the first time that the six-photon GHZ (ie, non-bipartite) The research results were published in the Physical Review Letters, December 23rd and Selected as Editors' Suggestion by Physical Review Letters. Quantum nonlocality is one of the core issues of quantum information and quantum physics, and is an important resource for quantum communication and quantum computing. The nonlocality (Bell inequality) of two bodies has been studied deeply. However, there are still many problems of quantum nonlocality in many cases. In order to verify the multi-body non-locality, many methods have been proposed, including GHZ paradox and Mermin inequality. Among them, the GHZ paradox has aroused great interest because of its non-statistical properties. The GHZ paradox is to construct a series of measurements, quantum mechanics and local latent variables theory to make the exact opposite prediction of the measurement results, which makes it possible to experimentally decide whether the theories of quantum mechanics and latent variables are right There is no need to judge by the statistical calculation of a large amount of data like Bell inequality and Mermin inequality. However, the non-local verification of "non-equivalence" requires very high fidelity of entangled states. Although people have been able to prepare six-photon or even eight-photon entangled states in recent years, their fidelity is limited. At present, the experimental test of the multiphoton GHZ paradox still stays in the four-photon phase. On the one hand, Li Chuan-feng and Huang Yun-feng put forward the universal construction method of multi-body GHZ paradox; on the other hand, based on the self-developed "beamlike" type of entangled source, the "sandwiched" entangled source is ingeniously designed. The new type of entangled source has better symmetry so that the entangled photon pair achieves a compliance efficiency of 0.29 and a degree of entanglement of 99% with a brightness of 2000 pairs per second for a pump of milliwatts, which exceeds All previous reports of multiphoton experiments. The fidelity of the six-photon GHZ state prepared by the research group thus reached as high as 88.4%, creating the highest level in the world. Based on the above research results, the research team verified the six-photon GHZ type nonlocality. Sandwich-type entanglement source diagram REVIEWER ASSESSMENT This work sets a new standard for fidelity and brightness in multiphoton experiments ("The experiments sets a new standard in terms of fidelity and brightness in multiphoton experiments"). The results of quantum communication networks, quantum computing and quantum physics research will bring a significant contribution to the promotion of. The first author of the paper is Zhang Chao, a doctoral student in Key Laboratory of Quantum Information, Chinese Academy of Sciences. The work has been funded by the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences and the Ministry of Education. Electric Motorcycle Cross,Electric Motorcycle For Adults,Cheap Electric Motorcycle,Fastest Electric Motorcycle Wu Xi Mdka New Energy Technology Co., Ltd. , https://www.evmdka.com