General method for extracting the quantum efficiency of dispersive qubit readout in circuit QED
article
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. © 2018 Author(s).
Topics
TNO Identifier
787772
ISSN
0003-6951
Source
Applied Physics Letters, 112(9)
Article nr.
092601