Voltage-Controlled Superconducting Quantum Bus

  1. L. Casparis,
  2. N. J. Pearson,
  3. A. Kringhøj,
  4. T. W. Larsen,
  5. F. Kuemmeth,
  6. J. Nygård,
  7. P. Krogstrup,
  8. K. D. Petersson,
  9. and C. M. Marcus
We demonstrate the ability of an epitaxial semiconductor-superconductor nanowire to serve as a field-effect switch to tune a superconducting cavity. Two superconducting gatemon qubits
are coupled to the cavity, which acts as a quantum bus. Using a gate voltage to control the superconducting switch yields up to a factor of 8 change in qubit-qubit coupling between the on and off states without detrimental effect on qubit coherence. High-bandwidth operation of the coupling switch on nanosecond timescales degrades qubit coherence.