Kuang Liu, Zhiyuan Wang, Xiaoliang He, Siqi Li, Hao Wu, Xiangyu Ren, Zhengqi Niu, Wangpeng Gao, Chenluo Zhang, Pei Huang, Yu Wu, Liliang Ying, Wei Peng, Jaw-Shen Tsai, Zhirong Lin

The development of large-scale superconducting quantum computing requires efficient in-situ control methods that allow high-fidelity operations at millikelvin temperatures. Superconducting circuits based on Josephson junctions offer a promising solution due to their high speed, low power dissipation, and cryogenic nature. Here, we report a superconducting quantum controller that enables direct chip-to-chip interconnection with qubits at 10 mK and high-fidelity, all-digital manipulation. Randomized benchmarking reveals a uniformly high average Clifford fidelity of 99.9% with leakage to high energy levels on the order of $10^{-4}$, and an estimated average gate operation energy of 0.121 fJ, demonstrating the potential to resolve the control bottleneck in superconducting quantum computing.