Improved material loss measurement using cryogenic resonator testbed

Loss measurements are critical for the superconducting qubit community as the coherence of quantum systems are limited by loss through energy relaxation. The standard procedure for measuring loss is to design and fabricate resonators that incorporate the material-under-test and measure the temperature, power, and geometry dependence. By analyzing the transmission S₂₁ data on complex plane, it is possible to extract the internal quality factor, Q_i, i.e. the inverse of the loss tangent of the material. However, there are several variations of experimental set-up, measurement and fitting algorithms used in the field. This results in uncertainty when comparing Q_i values between research groups. In this talk, we will compare the results of different measurement configurations, especially for input and output line filtering and isolation, and quantify the accuracy of loss measurement in order to identify best practices for resonator measurement and setup procedures.