Author(s): Liao, SK (Liao, Sheng-Kai); Cai, WQ (Cai, Wen-Qi); Handsteiner, J (Handsteiner, Johannes); Liu, B (Liu, Bo); Yin, J (Yin, Juan); Zhang, L (Zhang, Liang); Rauch, D (Rauch, Dominik); Fink, M (Fink, Matthias); Ren, JG (Ren, Ji-Gang); Liu, WY (Liu, Wei-Yue); Li, Y (Li, Yang); Shen, Q (Shen, Qi); Cao, Y (Cao, Yuan); Li, FZ (Li, Feng-Zhi); Wang, JF (Wang, Jian-Feng); Huang, YM (Huang, Yong-Mei); Deng, L (Deng, Lei); Xi, T (Xi, Tao); Ma, L (Ma, Lu); Hu, T (Hu, Tai); Li, L (Li, Li); Liu, NL (Liu, Nai-Le); Koidl, F (Koidl, Franz); Wang, PY (Wang, Peiyuan); Chen, YA (Chen, Yu-Ao); Wang, XB (Wang, Xiang-Bin); Steindorfer, M (Steindorfer, Michael); Kirchner, G (Kirchner, Georg); Lu, CY (Lu, Chao-Yang); Shu, R (Shu, Rong); Ursin, R (Ursin, Rupert); Scheidl, T (Scheidl, Thomas); Peng, CZ (Peng, Cheng-Zhi); Wang, JY (Wang, Jian-Yu); Zeilinger, A (Zeilinger, Anton); Pan, JW (Pan, Jian-Wei) 

Source: PHYSICAL REVIEW LETTERS  Volume: 120  Issue: 3  Article Number: 030501  DOI: 10.1103/PhysRevLett.120.030501  Published: JAN 19 2018   

Abstract: We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with similar to kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive OR operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network. 

ISSN: 0031-9007