Efficient and robust analysis of complex scattering data under noise in microwave resonators

TL;DR

This paper presents a fast, noise-robust method for analyzing complex scattering data in microwave resonators, crucial for applications requiring high precision and speed in material research and quantum measurements.

Contribution

It introduces a non-iterative, algebraic circle fitting algorithm with diameter correction for reliable quality factor extraction under noisy conditions.

Findings

Enhanced robustness against noise in quality factor estimation

Significant speedup over traditional iterative methods

Applicable to single photon regime measurements

Abstract

Superconducting microwave resonators are reliable circuits widely used for detection and as test devices for material research. A reliable determination of their external and internal quality factors is crucial for many modern applications, which either require fast measurements or operate in the single photon regime with small signal to noise ratios. Here, we use the circle fit technique with diameter correction and provide a step by step guide for implementing an algorithm for robust fitting and calibration of complex resonator scattering data in the presence of noise. The speedup and robustness of the analysis are achieved by employing an algebraic rather than an iterative fit technique for the resonance circle.