Characterizing microwave losses in superconducting quantum circuits: Part 1

The performance of superconducting quantum circuits has advanced tremendously in the past two decades, with coherence times increasing by over six orders of magnitude. In the past, improvements have been made by modifying circuit geometry; recently, improvements have been achieved through advancements in materials and processing. As coherence times continue to rise, it is becoming less apparent which loss mechanism dominates the total internal loss of transmon qubits and microwave resonators. In this talk, we will present a method using on-chip multimode microwave stripline resonators to distinguish between sources of loss in superconducting quantum circuits. We will measure loss factors associated with mechanisms such as bulk dielectric loss and surface loss, and demonstrate how they differ between various material platforms.