Cryogenic Thermalization Measurements of Microwave Attenuators

ORAL

Abstract

Dephasing due to residual thermal photons in readout cavities is a leading factor in limiting the coherence of superconducting qubits. This thermal noise originates from strong cavity drives and poor thermalization of microwave attenuators. It has been shown that cold attenuators could allow one to approach the qubit decoherence limits imposed by T1 [1]. We thus study the thermalization of cryo-attenuators by using a coaxial stub cavity over-coupled to a microwave input line for absolute temperature measurement. In particular, we look at the power dependence and the time constant for the temperature of a few attenuator designs, and discuss strategies for improvement.

[1] Z. Wang, et. al. Phys. Rev. Applied 11, 014031 (2019)

*We acknowledge support from the U.S. Army Research Office Grant Nr. W911NF-18-1-0212

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Presenters

  • Aniket Maiti

    • Yale University

Authors

  • Aniket Maiti

    • Yale University

  • Vijay Jain

    • Yale University

  • Luigi Frunzio

    • Yale University
    • Department of Applied Physics, Yale University
    • Departments of Applied Physics and Physics, Yale University

  • Robert Schoelkopf

    • Yale University
    • Department of Applied Physics, Yale University
    • Departments of Applied Physics and Physics, Yale University