Magnetic Field Tolerant Superconducting Spiral Resonators for Circuit QED

TL;DR

This paper introduces spiral niobium superconducting resonators with high magnetic field tolerance and quality factors, suitable for quantum devices requiring high impedance and magnetic resilience.

Contribution

The authors develop and characterize spiral niobium resonators with high impedance, high critical magnetic fields, and high quality factors, demonstrating their potential for magnetic field resilient quantum circuits.

Findings

Resonators achieve impedance of 3.25-7.09 kΩ.

Maintain quality factor above 10^5 at 1 T magnetic field.

Exhibit high magnetic field tolerance and low losses.

Abstract

We present spiral resonators of thin film niobium (Nb) that exhibit large geometric inductance, high critical magnetic fields and high single photon quality factors. These low loss geometric inductors can be a compelling alternative to kinetic inductors to create high-impedance superconducting devices for applications that require magnetic fields. By varying the spiral pitch, we realize resonators with characteristic impedances ranging from 3.25-7.09 k{\Omega}. We measure the temperature and magnetic field dependent losses and find that the high-impedance resonators maintain an intrinsic quality factor above {\sim} 10^5 for parallel magnetic fields of up to 1 T. These properties make spiral Nb resonators a promising candidate for quantum devices that require circuit elements with high impedance and magnetic field resilience.