Related papers: Tuning microwave losses in superconducting resonat…
We describe the fabrication and measurement of microwave coplanar waveguide resonators with internal quality factors above 10 million at high microwave powers and over 1 million at low powers, with the best low power results approaching 2…
Superconducting circuits are arguably taking a leading role in driving the ongoing quantum technological revolution. A detailed knowledge of the microscopic fluctuating electromagnetic properties plays an important role in advancing the…
Disordered superconducting materials with high kinetic inductance are an important resource to generate nonlinearity in quantum circuits and create high-impedance environments. In thin films fabricated from these materials, the combination…
Measuring the internal quality factor of coplanar waveguide superconducting resonators is an established method of determining small losses in superconducting devices. Traditionally, the resonator losses are only attributed to two-level…
Research on diamond has intensified due to its exceptional thermal, optical, and mechanical properties, making it a key material in quantum technologies and high-power applications. Diamonds with engineered nitrogen-vacancy (NV) centers…
We present a lab-on-chip experiment to accurately measure losses of superconducting microstrip lines at microwave and sub-mm wavelengths. The microstrips are fabricated from NbTiN, which is deposited using reactive magnetron sputtering, and…
Bulk niobium has long been the material of choice for superconducting radio-frequency applications. An alternative approach is the superconductor-insulator-superconductor multilayer structure, which enables the use of brittle high-$T_c$…
In this work, microwave measurements carried out in dielectric-loaded resonators exposed to high magnetic fields are exploited to yield the surface impedance of Nb$_3$Sn superconducting coatings deposited via two different techniques: vapor…
We report a study of the microwave conductivity of electron-doped Pr$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta}$ superconducting thin films using a cavity perturbation technique. The relative frequency shifts obtained for the samples placed at a…
Superconducting quantum circuits are one of the leading quantum computing platforms. To advance superconducting quantum computing to a point of practical importance, it is critical to identify and address material imperfections that lead to…
The superconducting materials that make up an MKID have a significant effect on its performance. The $T_\textrm{c}$ and normal state resistivity $\rho_\textrm{N}$ of the film determine the penetration depth $\lambda$ and therefore how much…
Parasitic electromagnetic fields are shown to strongly suppress the quality (Q)-factor of superconducting coplanar waveguide resonators via non-local dissipation in the macroscopic environment. Numerical simulation and low temperature…
Radio frequency (RF) superconductivity has become a key technology for many modern particle accelerators. One of its most salient features of this technology is the ability of superconducting RF cavities to deliver high accelerating…
Superconducting coplanar waveguide resonators that can operate in strong magnetic fields are important tools for a variety of high frequency superconducting devices. Magnetic fields degrade resonator performance by creating Abrikosov…
Electropolishing is the premier surface preparation method for high-Q, high-gradient superconducting RF cavities made of Nb. This leaves behind an apparently smooth surface, yet the achievable peak magnetic fields fall well below the…
Microwave loss in niobium metallic structures used for superconducting quantum circuits is limited by a native surface oxide layer formed over a timescale of minutes when exposed to an ambient environment. In this work, we show that…
We describe a thin-film superconducting Nb microwave resonator, tunable to within 0.3 ppm of the hyperfine splitting of $^{87}$Rb at $f_{Rb}=6.834683$ GHz. We coarsely tuned the resonator using electron-beam lithography, decreasing the…
Microwave cavity resonators are crucial components of many quantum technologies and are a promising platform for hybrid quantum systems, as their open architecture enables the integration of multiple subsystems inside the cavity volume. To…
The electronic properties of superconducting Sn films ($T_c \approx$ 3.8 K) change significantly when reducing the film thickness down to a few nm, in particular close to the percolation threshold. The low-energy electrodynamics of such Sn…
Superconducting coplanar waveguide (SCPW) resonators with high internal quality factors (\Q_i) are essential for quantum information applications, but suffer severe Qi degradation under magnetic fields due to quasiparticle generation and…