INFORMATION TECHNOLOGY

High-speed metro quantum teleportation


Guide

Recently, the research group of Zhou Qiang, the team of academician Guo Guangcan of the University of Electronic Science and Technology of China, and the team of You Lixing of the Shanghai Institute of Microsystems of the Chinese Academy of Sciences, have made significant progress in the “Ginkgo-1” metro quantum Internet of the University of Electronic Science and Technology of China (see Figure 1). The research team developed a high-repetition frequency quantum light source, an automated photonic all-identical measurement and control device, and a high-performance superconducting nanowire single-photon detector, breaking through technical problems such as quantum information carrier, quantum channel establishment, and quantum information detection, and completing metro quantum teleportation at “Hertz rate” for the first time. The research results play an important role in the development of a new generation of information technology based on quantum entanglement.

Figure 1: Aerial view and design concept of the Ginkgo-1 metro quantum Internet construction site

Research background

With the help of quantum physics resources, quantum information technology can provide people with information acquisition, transmission and processing technology beyond classical physics, and its ultimate development goal is to establish a quantum Internet, or quantum network. One of the key tasks of realizing the quantum Internet is to complete the transmission of quantum information between different quantum nodes. With the help of quantum entanglement resources, with the assistance of quantum projection measurement and classical communication, quantum teleportation can “transfer unknown quantum information”. Since the quantum teleportation protocol was proposed in the 90s of the 20th century, researchers have carried out a large number of theoretical and experimental studies in different physical systems.

Among them, quantum teleportation based on quantum optical scheme provides an important scheme for the construction of quantum Internet, including continuous variable (CV) and discrete variable (DV) two quantum physical systems. Facing the construction of quantum Internet on a global scale, the quantum teleportation of the DV system is expected to extend the quantum information transmission distance to thousands of kilometers. At present, based on the DV system, scientists have completed quantum teleportation from indoor to outdoor field on different degrees of photon freedom. For example, based on the “Micius” satellite, thousands of kilometers of quantum teleportation have been experimentally verified. Based on these remarkable works, this paper reports for the first time that high-speed metro quantum teleportation with a transmission rate of the hertz order plays a crucial role in promoting the sustainable development of the quantum Internet.

Innovative research

The “Ginkgo-1” metro quantum Internet built in this thesis uses decoy time-slice qubits to encode the transmitted quantum information, and on the basis of breaking through the following key technologies, the rate of metro quantum teleportation is increased to the hertz order for the first time.

(1) High repetition quantum entanglement light source: The research team developed a quantum entanglement light source with independent intellectual property rights, and used a single pigtail coupling periodically polarized lithium niobate waveguide module to achieve a high-quality quantum entanglement light source triggered by 500 MHz refrequency.

(2) Automated photon all-identical measurement and control device: In order to ensure the success of quantum teleportation and improve the efficiency of Bell state projection measurement, it is necessary to ensure that the photons from Alice and Bob remain identical after long-distance optical fiber transmission. The research team independently developed an automated photon all-identical measurement and control device, which realized a fast-response optical fiber channel photon all-identical stability measurement and control technology by sensing the photon polarization and delay information in the quantum channel in real time.

(3) High-performance superconducting nanowire single-photon detector: The team of You Lixing of the Shanghai Institute of Microsystems, Chinese Academy of Sciences provided a high-performance superconducting nanowire single-photon detector with high detection efficiency, low dark count, and low time jitter for high-efficiency Bell state projection measurement and optical quantum state detection process.

Furthermore, the research team used quantum state tomography and decoy state methods (see Figure 2) to obtain that the fidelity of teleportation was greater than the classical limit (66.7%), and obtained the quantum state transfer rate through triple correspondence measurement, which confirmed that high-speed metro quantum teleportation was experimentally realized.

Figure 2: Typical quantum state transfer fidelity results

Summary and outlook

Through the construction of the “Ginkgo-1” metro quantum Internet, the research team has realized high-speed metro quantum teleportation with a transmission rate of the hertz order. Combined with core devices such as integrated quantum light source, quantum storage relay, and quantum information node, it is expected to develop “high-rate, high-fidelity, multi-user, long-distance” quantum Internet facilities in the future, and further promote the practical application of quantum Internet.

The article was published in Light: Science & Applications in the top international academic journal “Hertz-rate metropolitan quantum teleportation”. This work has been strongly supported by the National Key R&D Program, the Sichuan Provincial Key R&D Program, the National Natural Science Foundation of China and Hefei National Laboratory. Shen Si, a doctoral student at the University of Electronic Science and Technology of China, is the first author of this paper, and Professor Zhou Qiang is the corresponding author of this paper. (Source: LightScience Applications WeChat public account)

Related paper information:https://www.nature.com/articles/s41377‍-023-0‍1158-7

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