Superradiant Hybrid Quantum Devices

TL;DR

This paper demonstrates superradiance in a hybrid quantum system of superconducting resonators and NV centers, showing a superradiant pulse much faster than individual emitters, paving the way for advanced quantum devices.

Contribution

It provides the first clear experimental observation of superradiance in a hybrid superconducting-NV system, with nonlinear emission scaling confirming superradiant behavior.

Findings

Superradiant pulse emitted a trillion times faster than individual NV centers.

Non-linear scaling of emitted radiation with ensemble size.

Foundation for future solid-state superradiant quantum devices.

Abstract

Superradiance is the archetypical collective phenomenon where radiation is amplified by the coherence of emitters. It plays a prominent role in optics, where it enables the design of lasers with substantially reduced linewidths, quantum mechanics, and is even used to explain cosmological observations like Hawking radiation from black holes. Hybridization of distinct quantum systems allows to engineer new quantum metamaterials pooling the advantages of the individual systems. Superconducting circuits coupled to spin ensembles are promising future building blocks of integrated quantum devices and superradiance will play a prominent role. As such it is important to study its fundamental properties in hybrid devices. Experiments in the strong coupling regime have shown oscillatory behaviour in these systems but a clear signature of Dicke superradiance has been missing so far. Here we explore superradiance in a hybrid system composed of a superconducting resonator in the fast cavity limit inductively coupled to an inhomogeneously broadened ensemble of nitrogen-vacancy (NV) centres. We observe a superradiant pulse being emitted a trillion of times faster than the decay for an individual NV centre. This is further confirmed by the non-linear scaling of the emitted radiation intensity with respect to the ensemble size. Our work provides the foundation for future quantum technologies including solid state superradiant masers.