Date of Award

Summer 8-27-2021

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

Advisor(s)

Plourde, Britton

Second Advisor

Chakraborty, Arindam

Keywords

Circuit quantum electrodynamics, Multimode circuit quantum electrodynamics, Quantum computation, Superconducting metamaterial resonators

Subject Categories

Physical Sciences and Mathematics | Physics

Abstract

Superconducting devices in circuit quantum electrodynamics (cQED) systems are one of the leading approaches for realizing scalable quantum information processors. The combination of cQED architectures with multimode resonator systems can provide a flexible platform for performing analog quantum simulations, storing quantum information, and generating complex entangled states. Metamaterial resonant structures made from arrays of superconducting lumped circuit elements can exhibit microwave mode spectra with left-handed dispersion, resulting in a high density of modes in the same frequency range where superconducting qubits are typically operated, as well as a bandgap at lower frequencies that extends down to dc. In this thesis, we present a brief review of the design, fabrication, and circuit properties of superconducting metamaterial resonators. Through a series of low-temperature measurements, we study the coupling of a flux-tunable transmon qubit to a dense spectrum of microwave modes generated by a superconducting metamaterial resonator. We measure the interaction between the transmon and metamaterial by both direct microwave transmission through the metamaterial resonator and qubit spectroscopy and manipulation through a separate readout cavity. We study the qubit decay and decoherence as a function of frequency in the presence of the dense mode spectrum. We also investigate the ac Stark shift of the qubit as the photon number in the various metamaterial modes is varied. Additionally, we compare these measurements with analytical and circuit simulation results.

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Open Access

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