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Professor Chen’s Research Team: The Multi-User Entanglement Swapping

December 20, 2019      Author: Li Yuanhua

The latest results of SJTU Professor Chen Xianfeng's research team, School of Physics and Astronomy and the researchers in the field of quantum information research is published by Physical Review Letters, a world-renowned journal of international physics, titled "Multi-user time-energy entanglement swapping based on dense wavelength division multiplexed and sum-frequency generation". The researchers proposed a dense wavelength-division multiplexing (DWDM) quantum network based on quantum entanglement switching, and demonstrated its feasibility experimentally, which is important for building large-scale optical fiber quantum networks in the future. The paper was published online on December 20.

The first author of this paper is Li Yuanhua, PhD, former student of Professor Chen Xianfeng at SJTU, now researcher and teacher at Jiangxi Normal University. Li Yuanhua is now engaged in postdoctoral research in the group of Professor Chen, who is the corresponding author of the research. The paper is co-authored by Yuan Yu, Special Researcher of SJTU, Professor Sang Minghuang of Jiangxi Normal University and Professor Yan Yiyou. The research work is supported by the National Key Research Program (Project No. 2017 YFA0303701), National Natural Science Foundation (project number No. 11734011, 11804135, 11764021, 61765008) and the Shanghai Science and Technology Commission's major projects (project number No. 17JC1400402).



Perfect entanglement swapping, which can be realized without the postselection by using the nonlinear optical technology, provides an important way toward generating the large-scale quantum network. We explore an entanglement-swapping-based dense wavelength division multiplexed network in the experiment. Four users receive single quantum states at different wavelengths, and we perform a time-energy entanglement swapping operation based on the sum-frequency generation to make users fully connected in the network. The results show that the fidelity of the entangled state is larger than 90% and is independent of the number of users. Our Letter demonstrates the feasibility of a proposed multiuser network, and hence paves a route toward a variety of quantum applications, including entanglement-swapping-based quantum direct communication.

Read the article: https://link.aps.org/doi/10.1103/PhysRevLett.123.250505


Translated by Iga Kowalewska       Reviewed by Wang Bingyu