A tunable coupling scheme for implementing high-fidelity two-qubit gates

  1. Fei Yan,
  2. Philip Krantz,
  3. Youngkyu Sung,
  4. Morten Kjaergaard,
  5. Dan Campbell,
  6. Joel I.J. Wang,
  7. Terry P. Orlando,
  8. Simon Gustavsson,
  9. and William D. Oliver
The prospect of computational hardware with quantum advantage relies critically on the quality of quantum gate operations. Imperfect two-qubit gates is a major bottleneck for achieving scalable quantum information processors. Here, we propose a generalizable and extensible scheme for a two-qubit coupler switch that controls the qubit-qubit coupling by modulating the coupler frequency. Two-qubit gate operations can be implemented by operating the coupler in the dispersive regime, which is non-invasive to the qubit states. We investigate the performance of the scheme by simulating a universal two-qubit gate on a superconducting quantum circuit, and find that errors from known parasitic effects are strongly suppressed. The scheme is compatible with existing high-coherence hardware, thereby promising a higher gate fidelity with current technologies.
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