Dependence of transmon qubit relaxation rate on cavity photon population

ORAL

Abstract

In circuit QED experiments, a qubit is dispersively coupled to a cavity such that the cavity frequency depends on the qubit state. This dispersive shift enables quantum non-demolition readout of the qubit by exciting the cavity with a microwave pulse and detecting the phase shift of the reflected signal. However, this cavity excitation has been observed in experiments to increase the qubit relaxation rate, hence demolishing the qubit state and limiting the maximum measurement strength. Here we experimentally study this effect in a transmon qubit coupled to a three-dimensional superconducting cavity. We also explore alternate qubit circuits designed to mitigate this demolition effect.

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Authors

  • S.O. Mundhada

    Department of Applied Physics, Yale University

  • S. Shankar

    Yale Univ, Department of Applied Physics, Yale University

  • Yehan Liu

    Yale University, Department of Applied Physics, Yale University

  • M. Hatridge

    Yale Univ, Department of Applied Physics, Yale University

  • A. Narla

    Yale Univ, Department of Applied Physics, Yale University

  • K.M. Sliwa

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

  • S.M. Girvin

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

  • M.H. Devoret

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