Slow noise processes in superconducting resonators

TL;DR

This study investigates slow flicker frequency noise in superconducting resonators, revealing how it varies with drive power, temperature, and dielectric layers, and identifying different noise behaviors.

Contribution

It provides a detailed comparison of flicker noise in bare and dielectric-layered superconducting resonators under various conditions, highlighting new insights into their noise mechanisms.

Findings

Flicker frequency noise increases as microwave drive decreases.

Temperature rise saturates flicker noise in dielectric-layered resonators.

Bare resonators transition from flicker noise to random frequency walk at higher temperatures.

Abstract

Slow noise processes, with characteristic timescales ~1s, have been studied in planar superconducting resonators. A frequency locked loop is employed to track deviations of the resonator centre frequency with high precision and bandwidth. Comparative measurements are made in varying microwave drive, temperature and between bare resonators and those with an additional dielectric layer. All resonators are found to exhibit flicker frequency noise which increases with decreasing microwave drive. We also show that an increase in temperature results in a saturation of flicker noise in resonators with an additional dielectric layer, while bare resonators stop exhibiting flicker noise instead showing a random frequency walk process.