Dispersive Response of a Disordered Superconducting Quantum Metamaterial

TL;DR

This paper investigates how disorder affects the dispersive response of a superconducting quantum metamaterial, demonstrating that phase shift measurements can resolve individual qubit resonances despite decoherence, aligning with experimental results.

Contribution

It introduces a model for disordered superconducting metamaterials and shows how phase measurements can identify individual qubit resonances despite high decoherence.

Findings

Photon phase shifts distinguish resonances in large qubit arrays.

Disorder does not prevent resonance detection despite decoherence.

Simulation results agree with recent experimental data.

Abstract

We consider a disordered quantum metamaterial formed by an array of superconducting flux qubits coupled to microwave photons in a cavity. We map the system on the Tavis-Cummings model accounting for the disorder in frequencies of the qubits. The complex transmittance is calculated with the parameters taken from state-of-the-art experiments. We demonstrate that photon phase shift measurements allow to distinguish individual resonances in the metamaterial with up to 100 qubits, in spite of the decoherence spectral width being remarkably larger than the effective coupling constant. Our simulations are in agreement with the results of the recently reported experiment.