Spectroscopy of three strongly coupled flux qubits

TL;DR

This paper presents spectroscopic measurements of three strongly coupled flux qubits, demonstrating complex spectra that align with theoretical models, and discusses implications for tunable qubit coupling.

Contribution

It provides experimental data on three strongly coupled flux qubits across various parameters, validating theoretical models and advancing qubit coupling control.

Findings

Spectra match eight-level theoretical predictions

Coupling energies range from 0.75 GHz to 6.05 GHz

Results inform tunable qubit coupling design

Abstract

We have carried out spectroscopic measurements of a system of three strongly coupled four-junction flux qubits. The samples studied cover a wide range of parameters with the coupling energy between neighboring qubits varying between 0.75 GHz and 6.05 GHz. The observed complicated spectra agree well with eight-level theory. The experiments are relevant for the realization of a tunable coupling between qubits.