Determining interface dielectric losses in superconducting coplanar waveguide resonators

TL;DR

This paper introduces a method to quantify and distinguish dielectric losses from various bulk and interfacial materials in superconducting coplanar waveguide resonators, aiding the enhancement of quantum circuit performance.

Contribution

It presents a novel approach combining statistical analysis and electromagnetic modeling to separately measure TLS losses from different dielectric interfaces in superconducting resonators.

Findings

Quantified TLS losses for specific dielectric interfaces.

Identified dominant loss mechanisms in superconducting CPW resonators.

Provided a tool for targeted material and fabrication improvements.

Abstract

Superconducting quantum computing architectures comprise resonators and qubits that experience energy loss due to two-level systems (TLS) in bulk and interfacial dielectrics. Understanding these losses is critical to improving performance in superconducting circuits. In this work, we present a method for quantifying the TLS losses of different bulk and interfacial dielectrics present in superconducting coplanar waveguide (CPW) resonators. By combining statistical characterization of sets of specifically designed CPW resonators on isotropically etched silicon substrates with detailed electromagnetic modeling, we determine the separate loss contributions from individual material interfaces and bulk dielectrics. This technique for analyzing interfacial TLS losses can be used to guide targeted improvements to qubits, resonators, and their superconducting fabrication processes.