Understanding Quality Factor Degradation in Superconducting Niobium Cavities at Low Microwave Field Amplitudes

Abstract

In niobium superconducting radio frequency (SRF) accelerating cavities a decrease of the quality factor at lower fields - a so called \emph{low field Q slope or LFQS} - has been a long-standing unexplained effect. By extending the high $Q$ measurement techniques to ultralow fields we discover two previously unknown features of the effect: i) saturation at rf fields lower than $E_{\mathrm{acc}}\sim 0.1$~MV/m; ii) strong degradation enhancement by growing thicker niobium pentoxide. Our findings suggest that the LFQS may be caused by the two level systems in the natural niobium oxide on the inner cavity surface, thereby identifying a new source of residual resistance and providing guidance for potential non-accelerator low field applications of SRF cavities.

arXiv commentfinal version

References in corpus (18)

• Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture
• Decoherence in Josephson Qubits from Dielectric Loss
• A quantum memory with near-millisecond coherence in circuit QED
• Experimental evidence for a surface distribution of two-level systems in superconducting lithographed microwave resonators
• Nitrogen and argon doping of niobium for superconducting radio frequency cavities: a pathway to highly efficient accelerating structures
• Surface loss simulations of superconducting coplanar waveguide resonators
• Observation of directly interacting coherent two-level systems in a solid
• Evidence for interacting two-level systems from the 1/f noise of a superconducting resonator
• Unprecedented Quality Factors at Accelerating Gradients up to 45 MV/m in Niobium Superconducting Resonators via Low Temperature Nitrogen Infusion
• Experimental demonstration of a resonator-induced phase gate in a multi-qubit circuit QED system
• Evidence of a nonequilibrium distribution of quasiparticles in the microwave response of a superconducting aluminium resonator
• Observation of classical-quantum crossover of 1/f flux noise and its paramagnetic temperature dependence
• Ultra-high quality factors in superconducting niobium cavities in ambient magnetic fields up to 190 mG
• A Cavity Experiment to Search for Hidden Sector Photons
• Dependence of the residual surface resistance of superconducting RF cavities on the cooling dynamics around $T_{\mathrm{c}}$
• Direct identification of dilute surface spins on Al${}_2$O${}_3$: Origin of flux noise in quantum circuits
• Decoherence Dynamics of Complex Photon States in a Superconducting Circuit
• Dependence of the microwave surface resistance of superconducting niobium on the magnitude of the rf field

Cited by in corpus (46)

• Materials loss measurements using superconducting microwave resonators
• Three-dimensional superconducting resonators at $T<20$ mK with the photon lifetime up to $\tau =2$ seconds
• Systematic Improvements in Transmon Qubit Coherence Enabled by Niobium Surface Encapsulation
• Superconducting cavity qubit with tens of milliseconds single-photon coherence time
• Programmable interference between two microwave quantum memories
• Ultra-Low Surface Resistance via Vacuum Heat Treatment of Superconducting Radiofrequency Cavities
• Dual-rail encoding with superconducting cavities
• Superfluid flow in disordered superconductors with Dynes pair-breaking scattering: depairing current, kinetic inductance, and superheating field
• High Quality 3-Dimensional Aluminum Microwave Cavities
• TOF-SIMS Analysis of Decoherence Sources in Nb Superconducting Resonators
• Flux expulsion in niobium superconducting radio-frequency cavities of different purity and essential contributions to the flux sensitivity
• Geometric Scaling of Two-Level-System Loss in Superconducting Resonators
• The Effect of Inhomogeneous Surface Disorder on the Superheating Field of Superconducting RF Cavities
• Introduction to Quantum Error Correction and Fault Tolerance
• Effects of anisotropy and disorder on the superconducting properties of Niobium
• A tunable High-Q millimeter wave cavity for hybrid circuit and cavity QED experiments
• First Scan Search for Dark Photon Dark Matter with a Tunable Superconducting Radio-Frequency Cavity
• Tuning microwave losses in superconducting resonators
• Non-Markovian Effects of Two-Level Systems in a Niobium Coaxial Resonator with a Single-Photon Lifetime of 10 ms
• Dissipative conductivity of a dirty superconductor with Dynes subgap states under a dc bias current up to the depairing current density
• Nonlinear Dynamics and Dissipation of a Curvilinear Vortex Driven by a Strong Time-Dependent Meissner Current
• Elucidating the local atomic and electronic structure of amorphous oxidized superconducting niobium films
• Oxygen Vacancies in Niobium Pentoxide as a Source of Two-Level System Losses in Superconducting Niobium
• High-Coherence Kerr-cat qubit in 2D architecture
• Deepest sensitivity to wavelike dark photon dark matter with superconducting radio frequency cavities
• High Frequency Nonlinear Response of Superconducting Cavity-Grade Nb surfaces
• Surface oxides, carbides, and impurities on RF superconducting Nb and Nb3Sn: A comprehensive analysis
• Modelling dielectric loss in superconducting resonators: Evidence for interacting atomic two-level systems at the Nb/oxide interface
• Millikelvin measurements of permittivity and loss tangent of lithium niobate
• Intrinsic Photon Loss at the Interface of Superconducting Devices
• Microscopic Examination of SRF-quality Nb Films through Local Nonlinear Microwave Response
• Vortex Dynamics and Dissipation Under High-amplitude Microwave Drive
• Measurements of the amplitude-dependent microwave surface resistance of an Au/Nb bilayer
• Unravelling the atomic and electronic structure of nanocrystals on superconducting Nb(110): Impact of the oxygen monolayer
• Compact inductor-capacitor resonators at sub-gigahertz frequencies
• Quasiparticle spectroscopy in technologically-relevant niobium using London penetration depth measurements
• Signatures of Enhanced Superconducting Properties in Niobium Cavities
• Discovery of Nb hydride precipitates in superconducting qubits
• Low barrier ZrO${}_x$-based Josephson junctions
• Multi-modal electron microscopy study on decoherence sources and their stability in Nb based superconducting qubit
• High temporal stability of niobium superconducting resonators by surface passivation with organophosphonate self-assembled monolayers
• Phase-controlled improvement of photon lifetime in coupled superconducting cavities
• Hydrogen and Deuterium Tunneling in Niobium
• Anomalous skin effect study of superconducting film
• Experimental Observation of Short-Range Magnetic Correlations in Amorphous Nb${}_2$O${}_5$ and Ta${}_2$O${}_5$ Thin Films
• Stability of superconducting resonators: motional narrowing and the role of Landau-Zener driving of two-level defects