Chinese scientists unlock long-distance quantum communications network

Chinese scientists at Peking University have made a significant breakthrough in long-distance quantum communication by demonstrating secure quantum communication over 2,300 miles (3,700 km) without relying on trusted relay nodes. Traditional Quantum Key Distribution (QKD) methods, while hack-proof, depend on these relay nodes, which introduce vulnerabilities and limit network scalability. The researchers overcame these challenges by eliminating relay nodes and using technology that can be manufactured at industrial scale, making the system more practical and scalable. Their approach involves a super optical comb on the server side, generating ultra-stable laser lines at identical frequencies, and 20 independent quantum transmitter chips on the client side that encode information into light pulses sent over standard fiber-optic cables. Each pair of chips communicated successfully over 230 miles (370 km), and collectively, the 20-chip system achieved the 2,300-mile range. The use of industry-standard wafers for chip fabrication and existing fiber-optic infrastructure suggests potential for scalable, intercity quantum networks supporting