Verification of a resetting protocol for an uncontrolled superconducting qubit

  1. Ming Gong,
  2. Feihu Xu,
  3. Zheng-Da Li,
  4. Zizhu Wang,
  5. Yu-Zhe Zhang,
  6. Yulin Wu,
  7. Shaowei Li,
  8. Youwei Zhao,
  9. Shiyu Wang,
  10. Chen Zha,
  11. Hui Deng,
  12. Zhiguang Yan,
  13. Hao Rong,
  14. Futian Liang,
  15. Jin Lin,
  16. Yu Xu,
  17. Cheng Guo,
  18. Lihua Sun,
  19. Anthony D. Castellano,
  20. Chengzhi Peng,
  21. Yu-Ao Chen,
  22. Xiaobo Zhu,
  23. and Jian-Wei Pan
We experimentally verify the simplest non-trivial case of a quantum resetting protocol with five superconducting qubits, testing it with different types of free evolutions and target-probe
interactions. After post-selection, we obtained a reset state fidelity as high as 0.951, and the process fidelity was found to be 0.792. We also implemented 100 randomly-chosen interactions and demonstrated an average success probability of 0.323, experimentally confirmed the non-zeros probability of success for unknown interactions; the numerical simulated value is 0.384. We anticipate this protocol will have widespread applications in quantum information processing science, since it is able to combat any form of free evolution.

Genuine 12-qubit entanglement on a superconducting quantum processor

  1. Ming Gong,
  2. Ming-Cheng Chen,
  3. Yarui Zheng,
  4. Shiyu Wang,
  5. Chen Zha,
  6. Hui Deng,
  7. Zhiguang Yan,
  8. Hao Rong,
  9. Yulin Wu,
  10. Shaowei Li,
  11. Fusheng Chen,
  12. Youwei Zhao,
  13. Futian Liang,
  14. Jin Lin,
  15. Yu Xu,
  16. Cheng Guo,
  17. Lihua Sun,
  18. Anthony D. Castellano,
  19. Haohua Wang,
  20. Chengzhi Peng,
  21. Chao-Yang Lu,
  22. Xiaobo Zhu,
  23. and Jian-Wei Pan
We report the preparation and verification of a genuine 12-qubit entanglement in a superconducting processor. The processor that we designed and fabricated has qubits lying on a 1D
chain with relaxation times ranging from 29.6 to 54.6 μs. The fidelity of the 12-qubit entanglement was measured to be above 0.5544±0.0025, exceeding the genuine multipartite entanglement threshold by 21 standard deviations. Our entangling circuit to generate linear cluster states is depth-invariant in the number of qubits and uses single- and double-qubit gates instead of collective interactions. Our results are a substantial step towards large-scale random circuit sampling and scalable measurement-based quantum computing.