Dimension Network learned from the Quantum Computing Chip Key Laboratory of Anhui Province that Origin Quantum, in collaboration with research teams from the University of Science and Technology of China and the Artificial Intelligence Research Institute of Hefei Comprehensive National Science Center, has successfully developed a "Coherent Quantum Routing System" for bucket-brigade Quantum Random Access Memory (QRAM) on the self-developed superconducting quantum computer "Origin Wukong," which is equivalent to building an "expressway" for data centers and effectively solving the industry challenge of QRAM expansion. The related paper was recently published in the international physics journal Physical Review X.

If a quantum computer is compared to a "smart city," then Quantum Random Access Memory (QRAM) serves as the "data center" that stores and schedules data within it. QRAM is a crucial functional module for implementing algorithms such as quantum search and quantum machine learning, with its core being the "quantum router"—which is responsible for accurately delivering data to target locations based on address instructions. However, in traditional schemes, as the routing network scale grows, each additional node requires a large number of standard quantum gates to decompose instructions layer by layer, leading to a sharp increase in circuit depth and error accumulation, which limits the expansion of QRAM.

To address this challenge, the research team proposed a quantum router construction scheme based on auxiliary energy levels. The "Coherent Quantum Routing System" utilizes the auxiliary energy levels of superconducting qubits to transform complex controlled-swap operations into a shallow-circuit equivalent implementation composed of a small number of two-qubit transition gates, which is equivalent to building an "expressway" above congested data channels, allowing data to bypass redundant nodes and reach destinations directly, significantly reducing circuit depth and lowering errors. The researchers actually constructed three independent quantum routers and a two-layer quantum routing network on the self-developed superconducting quantum computer "Origin Wukong" for testing. The results show that the information transmission efficiency of a single quantum router is as high as 98%, and the overall transmission efficiency of the two-layer routing network can also reach 93%. In random access tests, the average fidelity of a single quantum router reached 94.8%, and the average fidelity of the two-layer routing network reached 82.4%. The data indicates that this scheme can achieve coherent and reversible routing controlled by quantum addresses and has the potential to expand to larger-scale networks.

The researchers stated that this breakthrough not only provides a new path for building scalable QRAM on existing superconducting hardware but also marks a transition in China's quantum computing research and development from single-performance optimization to the stage of validating complex quantum functions on real hardware. By leveraging the inherent characteristics of quantum devices, lower-cost and higher-efficiency computation can be achieved, opening up new ideas for the collaborative optimization of quantum chips and circuits.