Magnetic imaging of superconducting qubit devices with scanning SQUID-on-tip

  1. E. Marchiori,
  2. L. Ceccarelli,
  3. N. Rossi,
  4. G. Romagnoli,
  5. J. Herrmann,
  6. J.-C. Besse,
  7. S. Krinner,
  8. A. Wallraff,
  9. and M. Poggio
We use a scanning superconducting quantum interference device (SQUID) to image the magnetic flux produced by a superconducting device designed for quantum computing. The nanometer-scale
SQUID-on-tip probe reveals the flow of superconducting current through the circuit as well as the locations of trapped magnetic flux. In particular, maps of current flowing out of a flux-control line in the vicinity of a qubit show how these elements are coupled, providing insight on how to optimize qubit control.