K. Fedorov

Tunable coupling of transmission-line microwave resonators mediated by an rf SQUID

  1. F. Wulschner,
  2. J. Goetz,
  3. F. R. Koessel,
  4. E. Hoffmann,
  5. A. Baust,
  6. P. Eder,
  7. M. Fischer,
  8. M. Haeberlein,
  9. M. J. Schwarz,
  10. M. Pernpeintner,
  11. E. Xie,
  12. L. Zhong,
  13. C. W. Zollitsch,
  14. B. Peropadre,
  15. J.J. García-Ripoll,
  16. E. Solano,
  17. K. Fedorov,
  18. E. P. Menzel,
  19. F. Deppe,
  20. A. Marx,
  21. and R. Gross
We realize tunable coupling between two superconducting transmission line resonators. The coupling is mediated by a non-hysteretic rf SQUID acting as a flux-tunable mutual inductance
between the resonators. From the mode distance observed in spectroscopy experiments, we derive a coupling strength ranging between -320MHz and 37 MHz. In the case where the coupling strength is about zero, the microwave power cross transmission between the two resonators can be reduced by almost four orders of magnitude compared to the case where the coupling is switched on. In addition, we observe parametric amplification by applying a suitable additional drive tone.
arxiv pdf

Tunable and Switchable Coupling Between Two Superconducting Resonators

  1. A. Baust,
  2. E. Hoffmann,
  3. M. Haeberlein,
  4. M. J. Schwarz,
  5. P. Eder,
  6. E. P. Menzel,
  7. K. Fedorov,
  8. J. Goetz,
  9. F. Wulschner,
  10. E. Xie,
  11. L. Zhong,
  12. F. Quijandria,
  13. B. Peropadre,
  14. D. Zueco,
  15. J.J. García-Ripoll,
  16. E. Solano,
  17. F. Deppe,
  18. A. Marx,
  19. and R. Gross
We realize a device allowing for tunable and switchable coupling between two superconducting resonators mediated by an artificial atom. For the latter, we utilize a persistent current
flux qubit. We characterize the tunable and switchable coupling in frequency and time domain and find that the coupling between the relevant modes can be varied in a controlled way. Specifically, the coupling can be tuned by adjusting the flux through the qubit loop or by saturating the qubit. Our time domain measurements allow us to find parameter regimes for optimal switch performance with respect to qubit drive power and the dynamic range of the resonator input power
arxiv pdf