Efficient methods for extracting superconducting resonator loss in the single-photon regime

Abstract

Superconducting micro-resonators have application in sensors and quantum computing. Measurement of the resonator internal loss in the single-photon regime is a common tool to study the origins of dissipation, noise, and decoherence in quantum circuits, as well as characterization of materials used for quantum devices. However, such measurements are challenging and time-consuming with large uncertainties due to the poor signal-to-noise ratio when measured at single-photon power levels. We developed methods to extract a subset of the resonator fitting parameters at high power and fix them in the analysis of low power data, which reduce the parameter space in the regression analysis. By comparing the analysis with and without partial extraction, we show that these methods reduce the uncertainty of the results, while improving the robustness and efficiency of the loss measurement.