Dynamic compensation for pump-induced frequency shift in Kerr-cat qubit initialization

  1. Yifang Xu,
  2. Ziyue Hua,
  3. Weiting Wang,
  4. Yuwei Ma,
  5. Ming Li,
  6. Jiajun Chen,
  7. Jie Zhou,
  8. Xiaoxuan Pan,
  9. Lintao Xiao,
  10. Hongwei Huang,
  11. Weizhou Cai,
  12. Hao Ai,
  13. Yu-xi Liu,
  14. Chang-Ling Zou,
  15. and Luyan Sun
The noise-biased Kerr-cat qubit is an attractive candidate for fault-tolerant quantum computation; however, its initialization faces challenges due to the squeezing pump-induced frequency shift (PIFS). Here, we propose and demonstrate a dynamic compensation method to mitigate the effect of PIFS during the Kerr-cat qubit initialization. Utilizing a novel nonlinearity-engineered triple-loop SQUID device, we realize a stabilized Kerr-cat qubit and validate the advantages of the dynamic compensation method by improving the initialization fidelity from 57% to 78%, with a projected fidelity of 91% after excluding state preparation and measurement errors. Our results not only advance the practical implementation of Kerr-cat qubits, but also provide valuable insights into the fundamental adiabatic dynamics of these systems. This work paves the way for scalable quantum processors that leverage the bias-preserving properties of Kerr-cat qubits.
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