General method for extracting the quantum efficiency of dispersive qubit readout in circuit QED
C. C. Bultink (Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre, TU Delft - QCD/DiCarlo Lab)
B. Tarasinski (TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, TU Delft - QCD/DiCarlo Lab)
N. Haandbæk (Zurich Instruments AG)
S. Poletto (Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre, TU Delft - QCD/DiCarlo Lab)
N. Haider (TU Delft - QuTech Advanced Research Centre, TU Delft - BUS/General, TNO)
D. J. Michalak (Intel Corporation)
A. Bruno (Kavli institute of nanoscience Delft, TU Delft - QCD/DiCarlo Lab, TU Delft - QuTech Advanced Research Centre)
L. DiCarlo (TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, TU Delft - QCD/DiCarlo Lab)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
We present and demonstrate a general three-step method for extracting the quantum efficiency of dispersive qubit readout in circuit QED. We use active depletion of post-measurement photons and optimal integration weight functions on two quadratures to maximize the signal-to-noise ratio of the non-steady-state homodyne measurement. We derive analytically and demonstrate experimentally that the method robustly extracts the quantum efficiency for arbitrary readout conditions in the linear regime. We use the proven method to optimally bias a Josephson traveling-wave parametric amplifier and to quantify different noise contributions in the readout amplification chain.