High Kinetic Inductance Superconducting Nanowire Resonators for Circuit QED in a Magnetic Field

Abstract: We present superconducting microwave-frequency resonators based on NbTiN nanowires. The small cross section of the nanowires minimizes vortex generation, making the resonators resilient to magnetic fields. Measured intrinsic quality factors exceed $2\times 10^5$ in a $6$ T in-plane magnetic field, and $3\times 10^4$ in a $350$ mT perpendicular magnetic field. Due to their high characteristic impedance, these resonators are expected to develop zero-point voltage fluctuations one order of magnitude larger than in standard coplanar waveguide resonators. These properties make the nanowire resonators well suited for circuit QED experiments needing strong coupling to quantum systems with small electric dipole moments and requiring a magnetic field, such as electrons in single and double quantum dots.