English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The control of material loss mechanisms is playing an increasingly importantrole for improving coherence times of superconducting quantum devices. Suchmaterial losses can be characterized through the measurement of planarsuperconducting resonators, which reflect losses through the resonance'squality factor $Q_l$. The resonance quality factor consists of both internal(material) losses as well as coupling losses when resonance photons escape backinto the measurement circuit. The combined losses are then described as$Q_l^{-1} = \mathrm{Re}\{Q_c^{-1}\} + Q_i^{-1}$, where $Q_c$ and $Q_i$ reflectthe coupling and internal quality factors of the resonator, respectively. Toseparate the relative contributions of $Q_i$ and $Q_c$ to $Q_l$,diameter-correcting circle fits use algebraic or geometric means to fit theresonance signal on the complex plane. However, such circle fits can producevaried results, so to address this issue, we use a combination of simulationand experiment to determine the reliability of a fitting algorithm across awide range of quality factor values from $Q_i\ll Q_c$ to $Q_c\ll Q_i$. Inaddition, we develop a novel measurement protocol that can not only reducefitting errors by factors $\gtrsim 2$ but also mitigates the influence of themeasurement background on the fit results. This technique can be generalizedfor other resonance systems beyond superconducting resonators.

Circle fit optimization for resonator quality factor measurements: point redistribution for maximal accuracy