Protection layers on a superconducting microwave resonator toward a hybrid quantum system

TL;DR

This paper proposes a multilayer protection scheme for superconducting microwave resonators to prevent degradation from optical photons and blackbody radiation, thereby enhancing their suitability for hybrid quantum systems involving cold atoms.

Contribution

The study introduces a novel multilayer dielectric and nanogrid structure that effectively shields microwave resonators from optical and thermal radiation, maintaining high quality factors.

Findings

Numerical simulations show improved quality factors with the protection layers.

The multilayer structure effectively reduces photon absorption and blackbody radiation effects.

Protection maintains resonator performance suitable for hybrid quantum applications.

Abstract

We propose a protection scheme of a superconducting microwave resonator to realize a hybrid quantum system, where cold neutral atoms are coupled with a single microwave photon through magnetic dipole interaction at an interface inductor. The evanescent field atom trap such as a waveguide/nanofiber atom trap, brings both surface-scattered photons and absorption-induced broadband blackbody radiation which result in quasiparticles and a low quality factor at the resonator. A proposed multiband protection layer consists of pairs of two dielectric layers and a thin nanogrid conductive dielectric layer above the interface inductor. We show numerical simulations of quality factors and reflection/absorption spectra, indicating that the proposed multilayer structure can protect a lumped-element microwave resonator from optical photons and blackbody radiation while maintaining a reasonably high quality factor.