Superconducting quantum metamaterials as active lasing medium: Effects of disorder

TL;DR

This paper investigates how disorder affects superconducting quantum metamaterials used as active lasing media, revealing that the lasing process remains robust and self-organized despite variations in atom parameters.

Contribution

It demonstrates the robustness of lasing in disordered superconducting metamaterials and provides quantitative relations for disorder scaling with atom number.

Findings

Lasing remains stable despite disorder in atom parameters.

Photon number increases with atom count and resonance width broadens.

Disorder effects scale predictably with system size and are confirmed numerically.

Abstract

A metamaterial formed by superconducting circuits or quantum dots can serve as active lasing medium when coupled to a microwave resonator. For these artificial atoms, in contrast to real atoms, variations in their parameters cannot be avoided. In this paper, we examine the influence of disorder on such a multi-atom lasing setup. We find that the lasing process evolves into a self-organized stationary state that is quite robust against disorder. The reason is that photons created by those atoms which are in or close to resonance with the resonator stimulate the emission also of more detuned atoms. Not only the number of photons grows with the number of atoms, but also the width of the resonance as function of the detuning. Similar properties are found for other types of disorder such as variations in the individual coupling. We present relations how the allowed disorder scales with the number of atoms and confirm it by a numerical analysis. We also provide estimates for the sample-to-sample variations to be expected for setups with moderate numbers of atoms.