Precision and resource scaling of real-time flux distortion compensation for superconducting quantum control

  1. Qi Zhou,
  2. Zi-Hao Mei,
  3. Peng Duan,
  4. Peng Wang,
  5. Liang-Liang Guo,
  6. Hao-Ran Tao,
  7. Wei-Cheng Kong,
  8. Hui Yang,
  9. Guo-Ping Guo,
  10. and Zhao-Yun Chen
Real-time waveform generation supports dynamic quantum circuits without pre-storing complete waveforms for every execution path. However, long-lived distortions in flux-control lines
degrade gate fidelity, requiring compensation to account for the actual pulse history. A frequency-domain inversion and time-domain fitting method is proposed for resource-efficient real-time flux distortion compensation. The method fits the reconstructed compensation impulse response with a compact hybrid infinite impulse response (IIR) and finite impulse response (FIR) filter. Look-ahead parallelization enables this filter to process synthesized waveforms at 1.2GSa/s on a field-programmable gate array (FPGA). Two-qubit cross-entropy benchmarking shows that real-time IIR filtering achieves a median controlled-Z Pauli fidelity close to the software-reference value of 99.57%. Numerical analysis and FPGA synthesis indicate approximately logarithmic growth in hardware resource use with compensation timescale. Extending compensation from microsecond to hundred-microsecond timescales increases look-up table (LUT) and digital signal processing (DSP) resource use by only about 14% and 4%, respectively, while maintaining a relative arithmetic error below 10−4. This work provides a scalable hardware foundation for high-fidelity flux control in dynamic superconducting quantum circuits.

Experimental Implementation of Short-Path Non-adiabatic Geometric Gates in a Superconducting Circuit

  1. Xin-Xin Yang,
  2. Liang-Liang Guo,
  3. Hai-Feng Zhang,
  4. Lei Du,
  5. Chi Zhang,
  6. Hao-Ran Tao,
  7. Yong Chen,
  8. Peng Duan,
  9. Zhi-Long Jia,
  10. Wei-Cheng Kong,
  11. and Guo-Ping Guo
The non-adiabatic geometric quantum computation (NGQC) has attracted a lot of attention for noise-resilient quantum control. However, previous implementations of NGQC require long evolution
paths that make them more vulnerable to incoherent errors than their dynamical this http URL this work, we experimentally realize a universal short-path non-adiabatic geometric gate set (SPNGQC) with a 2-times shorter evolution path on a superconducting quantum processor. Characterizing with both quantum process tomography and randomized benchmarking methods, we report an average single-qubit gate fidelity of 99.86% and a two-qubit gate fidelity of 97.9%. Additionally, we demonstrate superior robustness of single-qubit SP-NGQC gate to Rabi frequency error in some certain parameter space by comparing their performance to those of the dynamical gates and the former NGQC gates.