我国首次实现可扩展量子中继与百公里器件无关量子密钥分发

Core Insights - The research team from the University of Science and Technology of China has developed a scalable quantum relay basic module and achieved long-distance high-fidelity entanglement between single atomic nodes, marking a significant advancement in the practical application of quantum key distribution (DI-QKD) technology, with transmission distances exceeding 100 kilometers [1][2] Group 1: Quantum Relay Technology - The inherent loss of optical fibers leads to an exponential decay in the efficiency of quantum entanglement transmission over distance, making quantum relay schemes an effective solution to address fiber transmission losses [1] - A major technical challenge that has persisted for nearly 30 years is that the lifetime of entanglement is significantly shorter than the time required to generate it, hindering effective entanglement connection and scalability of quantum relays [1] - The research team has developed long-lifetime trapped ion quantum storage, high-efficiency ion-photon communication interfaces, and high-fidelity single-photon entanglement protocols, achieving a significant breakthrough with an entanglement lifetime of 550 milliseconds, surpassing the 450 milliseconds required for entanglement establishment [1] Group 2: Device-Independent Quantum Key Distribution - The traditional quantum secure communication schemes require precise calibration of device parameters to ensure real-world security, while the device-independent quantum key distribution (DI-QKD) scheme overcomes this limitation, ensuring key security even with completely untrusted quantum devices [2] - The implementation of DI-QKD has faced stringent technical barriers, with previous international experiments mostly limited to short distances of a few meters to hundreds of meters [2] - Utilizing scalable quantum relay technology, the research team successfully achieved long-distance high-fidelity entanglement between two rubidium atoms, breaking the DI-QKD distance barrier of 100 kilometers, improving upon the previous best international experimental level by over two orders of magnitude [2]