Minimal resonator loss for circuit quantum electrodynamics

TL;DR

This paper demonstrates high-quality factors in NbTiN superconducting resonators at millikelvin temperatures, highlighting the material's low dielectric loss and optimized design for quantum electrodynamics applications.

Contribution

It reports the achievement of record-high photon-level quality factors in NbTiN resonators by reducing dielectric loss and optimizing substrate design.

Findings

NbTiN resonators achieve Q factors of 500,000 at millikelvin temperatures

Low dielectric loss of NbTiN compared to Ta is confirmed

Removing unnecessary dielectric parts improves resonator performance

Abstract

Single photon level quality factors of 500x10^3 are shown in NbTiN superconducting resonators at millikelvin temperatures. This result originates from the intrinsic low dielectric loss of NbTiN, as demonstrated by comparison with Ta, and by removing unnecessary parts of the dielectric substrate.