Ten Milliseconds for Aluminum Cavities in the Quantum Regime

  1. M. Reagor,
  2. Hanhee Paik,
  3. G. Catelani,
  4. L. Sun,
  5. C. Axline,
  6. E. Holland,
  7. I.M. Pop,
  8. N.A. Masluk,
  9. T. Brecht,
  10. L. Frunzio,
  11. M.H. Devoret,
  12. L.I. Glazman,
  13. and R. J. Schoelkopf
A promising quantum computing architecture couples superconducting qubits to microwave resonators (circuit QED), a system in which three-dimensional microwave cavities have become a valuable resource. Such cavities have surface-to-volume ratios, or participation ratios a thousandfold smaller than in planar devices, deemphasizing potentially lossy surface elements by an equal amount. Motivated by this principle, we have tested aluminum superconducting cavity resonators with internal quality factors greater than 0.5 billion and intrinsic lifetimes reaching 0.01 seconds at single photon power and millikelvin temperatures. These results are the first to explore the use of superconducting aluminum, a ubiquitous material in circuit QED, as the basis of highly coherent (Q~10^7-10^9) cavity resonators. Measurements confirm the cavities‘ predicted insensitivity to quasiparticles (kinetic inductance fraction-5ppm) and an absence of two level dielectric fluctuations.
arxiv pdf

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