Quantum teleportation is realized in the urban fiber optic network

Pan Jianwei and Zhang Qiang from the University of Science and Technology of China, in cooperation with relevant agencies, first achieved the quantum state invisible transmission between independent quantum sources pre-entangled and distributed in Hefei Quantum Metro Test Network, laying a solid foundation for the future construction of an extensible quantum network basis. Relevant results on September 19 online published in the UK "Nature Photonics" on.

Quantum teleportation is an important means of communication that transfers quantum states and is the basis for scalable quantum networks and distributed quantum computing. In a nutshell, quantum teleportation is to restore the quantum information of a certain particle in site A to another particle in site B. The transmitted object is like an "interstellar crossing." The principle is: the two sides communicate first and foremost to share a pair of entangled particles, one of which will entangle the entangled particles in the quantum state to be transmitted (no correlation with entangled particles) and the entangled particles in their own hands, and then distinguish The result told each other, the other party according to the information obtained for the corresponding quantum transformation operation. Entangled pre-distribution, independent quantum interference and pre-feedback quantum teleportation of the three elements. Prior to this, there is not any one quantum teleportation experiment in the world that meets all the above requirements at the same time.

Pan Jianwei first collaborated with Tsinghua University to develop a time-phase entangled photon source suitable for optical fiber network transmission and successfully solved the problem of two independent photon sources by developing a picosecond-long remote optical synchronization technique and narrowband filtering using fiber Bragg gratings And then develop the active feedback system for the delay and polarization fluctuation caused by the long-distance optical fiber and the stability of the experimental system. Finally, using the superconducting nanowire single photon developed by Shanghai Institute of Microsystem, Chinese Academy of Sciences Detector, the quantum teleportation experiment satisfying the above three elements is realized on the 30 km optical fiber of Hefei Quantum Metro Network.

According to Zhang Qiang, the existing quantum secure communications mainly encrypt and transmit the classical information through the quantum key. However, with the development of technology, the final quantum secure communication will realize the transmission of quantum information, and quantum teleportation via optical fiber network State is expected to greatly improve the safety and strength of the Internet connection. In addition, if one day the advent of quantum computers, to carry out complex quantum information processing, you need to use quantum teleportation in the MAN to transmit quantum information.

The experiment was highly praised by reviewers as saying "it provides a blueprint for future applications of quantum communication networks." This first experimental verification will be due to the quantum role of teleportation in many quantum communication schemes Quantum technology is an important milestone in the development process. "Nature Photonics magazine invited international quantum information scholar Friedrich Gross Hans wrote in the same period" news perspective "column, saying the work" shows the city It is technically feasible to carry out quantum teleportation at the domain scale. No doubt, many interesting quantum information experiments will be conducted on this basis.