Master thesis defense by Jack Dienhart

The Decoherence Mechanisms of Superconducting Microwave Resonators

Superconducting microwave resonators are crucial for quantum processors and sensing applications, yet they lack standardized implementation due to varying processor layouts, materials, and fabrication techniques. This thesis reviews CPW resonators, covering design, simulation, fabrication, characterization, and analysis, with a special focus on controlling performance by understanding and mitigating loss mechanisms. Special attention is given to two-level system (TLS) losses, a major source of superconducting qubit decoherence. A new detector, the Tunneling System Detector Array, is proposed to measure and control these noisy dielectrics, aiming to enhance our understanding of how and why this decoherence emerges from amorphous materials. Addressing TLS alone could be the breakthrough needed to leave the NISQ era.