Characterization of a Single Quantum Meta-atom for a Superconducting Quantum Transmission Line Metamaterial

The quantum transmission line (QTL) metamaterial provides a unique opportunity to investigate emergent quantum phenomena, due to the strong coupling between the meta-atoms and the bosonic mode in the resonator as well as the quantum mechanical nature of such interaction. Two designs for QTL are considered in this study: flux and charge qubits embedded in a coplanar waveguide, the latter of which possesses interesting nonlinear coupling between neighboring meta-atoms that depend on the quantum state of the Josephson junction. Here we report the first step towards the realization of QTL metamaterial: the design, fabrication, and characterization of a single flux qubit in the coplanar waveguide. The characterization, which will eventually include vacuum Rabi splitting, Rabi oscillations, and quantum tomography, will be conducted through a microwave transmission measurement.