A plug-and-play superconducting quantum controller at millikelvin temperatures enables exceeding 99.9% average gate fidelity

  1. Kuang Liu,
  2. Zhiyuan Wang,
  3. Xiaoliang He,
  4. Siqi Li,
  5. Hao Wu,
  6. Xiangyu Ren,
  7. Zhengqi Niu,
  8. Wangpeng Gao,
  9. Chenluo Zhang,
  10. Pei Huang,
  11. Yu Wu,
  12. Liliang Ying,
  13. Wei Peng,
  14. Jaw-Shen Tsai,
  15. and 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.