Superconducting-circuit based platforms are strong contenders in the race to build a quantum computer.While the transmon has had extraordinary success as the leading superconducting qubit modality, there are reasons to believe that other types of qubits could possess relative benefits in terms of noise immunity, anharmonicity, or extensibility. In this thesis we explore multiple such next-generation superconducting circuits, focusing specifically on the current mirror and the fluxonium. Kitaev in 2006 proposed the current-mirror circuit, a type of superconducting qubit that should be protected from all types of local noise and could thus possess enhanced coherence times. We explore the spectrum and coherence properties of this device, while also developing numerical methods useful for studying other types of large superconducting circuits. Meanwhile, the highly-anharmonic fluxonium qubit has been shown experimentally to have coherence times competitive with or better than state-of-the-art transmons. Motivated by these results we explore a galvanic-coupling scheme for fluxonium qubits and utilize a framework going beyond typical rotating-wave approximation treatments to perform high-fidelity gates.

Creator

• Weiss, Daniel Kamrath

DOI

• https://doi.org/10.21985/n2-jwhc-z065

Subject

• Physics
• Quantum physics

Language

• en

Alternate Identifier

• etdadmin_upload_933500
• http://dissertations.umi.com/northwestern:16292

Keyword

• fluxonium
• Superconducting circuits
• Quantum computing
• current mirror

Date created

• 2022-01-01

Resource type

• Dissertation

Rights statement

• In Copyright