Chinese Team Tests Quantum Router With 98% Efficiency on Origin Wukong

Chinese researchers have tested a quantum router on the Origin Wukong superconducting quantum computer, reaching a transmission efficiency of up to 98%. The experiment is a step toward building scalable quantum random-access memory, or QRAM.

The work targets the bucket-brigade QRAM architecture, in which dedicated quantum routers direct information to specific memory cells. As memory size grows, so does the number of routers needed, and preserving a quantum state across multiple network layers is one of the biggest technical hurdles to scaling the design.

The team built three independent quantum routers and combined them into a two-layer network, testing the technology both as a single component and in the more complex setup. A single router reached a transmission efficiency of 98%; once combined into the two-layer system, that figure dropped to 93%. In random-access tests, quantum state fidelity reached 94.8% for a single router and 82.4% for the two-layer network.

The 98% figure reflects the performance of one experimental router, not the accuracy of the whole quantum computer or of QRAM as a system, and the drop as more layers are added shows the challenge researchers face in scaling the architecture. The tests ran on Origin Wukong, a third-generation Chinese superconducting quantum computer.

For now, this is an experimental demonstration of quantum routing rather than a working large-scale QRAM. The researchers say the next step is adding more routers and network layers while keeping transmission efficiency and state fidelity high, work that adds to a string of recent tests of quantum-networking hardware worldwide, from fiber-optic quantum links to satellite-based quantum communication trials.