Major breakthroughs were made in Chinese basic research of quantum communication technology again, a researcher at the Chinese university using linear optical system, implemented in 20 kilometers of fiber optic lines quantum fingerprint identification, is a classic limit for the first time in the world...

China university of science and technology of jian-wei pan and his colleagues zhang qiang, lilly, etc, and the Chinese academy of sciences Shanghai institute of microsystem and information technology, and the United States at the Massachusetts institute of technology researchers, using linear optical system, implemented in 20 kilometers of fiber optic lines Quantum fingerprint identification (Quantum Fingerprinting), break through the classical limit, on channel capacity for the first time realized with classical communication. The results of recently published in the international physics authoritative academic journal Physical Review Letters [Physical Review Letters, 116, 240502 (2016)].

With the rapid development of Internet technology and multimedia applications, especially the advent of the era of big data, optical communication network business is growing rapidly at a speed of exponential. Considering the limited resources, optical fiber links the least message for effective data processing and upgrade the capacity of the single fiber channel is the core of the optical communication academia and industry. Quantum Communication in addition to providing the unconditional security of information transmission means, but can be by Quantum Communication Complexity (Quantum Communication Complexity) research to increase the channel capacity to provide effective solutions. Research of quantum communication complexity by using the superposition principle of quantum mechanics, quantum channel can be used to provide higher channel capacity, is one of the important applications of quantum fingerprint identification. Fingerprint identification is mainly used in remote information than on both sides, suppose you want to compare the amount of information for N bits, classical method is the minimum amount of information needed to transfer into bits, and quantum fingerprint identification can be reduced to logN bits to transmit information, to improve the channel capacity index series.

Quantum fingerprint identification theory is put forward in 2001, but is limited by various technical conditions, the previous experiments on international has failed to break through the classical limit. Jian-wei pan team built with active phase compensation of 20 km long double Sagnac interferometer, combined with the Chinese academy of sciences Shanghai superconductor laboratory developed by micro system superconducting nanowires single photon detector of ultra low noise, finally realized the transmission of information 84% lower than the classical limit of quantum fingerprint identification. The laboratory is not only for the first time in the world of classical limit of quantum fingerprint identification, was observed in the experiments for the first time the superiority of the quantum channel capacity compared with the classical channel.

Reviewers high recognition to the importance of this work, praise this experiment for "provides a quantum key distribution outside the important application of quantum information" (" It is important to advance forward to implementations that dojo.provide a provable advantage thanks to the use of quantum resources, for separate protocols other than QKD. "), the European physical society affiliate sites "physical world" in the article, not published before the work was reported, citing the international famous quantum communication experts, Norbert Luetkenhaus comments, "the study will open many other (quantum communication) applications."

That the research work is quantum information and quantum frontier of science and technology innovation center for excellence of the Chinese academy of sciences, Chinese academy of sciences superconducting electronics excellence innovation center, Chinese academy of sciences - alibaba quantum computing laboratory, the foundation, the ministry of science and technology support, the ministry of education and other departments.