Nonlinear quantum processes in superconducting resonators terminated by neon-focused-ion-beam-fabricated superconducting nanowires

TL;DR

This paper explores nonlinear quantum phenomena in superconducting resonators with nanowires fabricated by neon focused-ion-beam, revealing flux-tunability and quantum tunneling effects at cryogenic temperatures.

Contribution

It introduces a novel fabrication method for superconducting nanowires and demonstrates their quantum nonlinear behavior in resonators.

Findings

Flux-tunable Nb Dayem bridges with high quality factors

Observation of incoherent quantum tunneling in NbN nanowires

Resonators maintain high performance at cryogenic temperatures

Abstract

We have used a neon focused-ion-beam to fabricate both nanoscale Nb Dayem bridges and NbN phase-slip nanowires located at the short-circuited end of quarter-wavelength coplanar waveguide resonators. The Dayem bridge devices show flux-tunability and intrinsic quality factor exceeding 10,000 at 300 mK up to local fields of at least 60 mT. The NbN nanowires show signatures of incoherent quantum tunnelling of flux at 300 mK.