Benchmarking the noise sensitivity of different parametric two-qubit gates in a single superconducting quantum computing platform

  1. M. Ganzhorn,
  2. G. Salis,
  3. D. J. Egger,
  4. A. Fuhrer,
  5. M. Mergenthaler,
  6. C. Müller,
  7. P. Müller,
  8. S. Paredes,
  9. M. Pechal,
  10. M. Werninghaus,
  11. and S. Filipp
The possibility to utilize different types of two-qubit gates on a single quantum computing platform adds flexibility in the decomposition of quantum algorithms. A larger hardware-native gate set may decrease the number of required gates, provided that all gates are realized with high fidelity. Here, we benchmark both controlled-Z (CZ) and exchange-type (iSWAP) gates using a parametrically driven tunable coupler that mediates the interaction between two superconducting qubits. Using randomized benchmarking protocols we estimate an error per gate of 0.9±0.03% and 1.3±0.4% fidelity for the CZ and the iSWAP gate, respectively. We argue that spurious ZZ-type couplings are the dominant error source for the iSWAP gate, and that phase stability of all microwave drives is of utmost importance. Such differences in the achievable fidelities for different two-qubit gates have to be taken into account when mapping quantum algorithms to real hardware.
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