Master's Defense: Chaoyue Wang

Implementation of Randomized Benchmarking Protocols on Superconducting Qubits

This thesis examines the effectiveness of Randomized Benchmarking (RB) protocols in assessing the fidelity of quantum gates in superconducting qubits through analytical and simulation-based approaches. By deriving expressions for average gate set infidelity and comparing these with RB numbers, the study provides insights into the dynamics and error characterization of quantum systems under various noise models. It highlights the practical utility of RB protocols, particularly Clifford RB, in reliably estimating gate infidelities and their role in quantum error characterization. The research extends existing theories to include leakage errors—a prominent error in superconducting qubits—and explores their impact on gate fidelity. Simulations demonstrate that while Clifford RB accurately estimates fidelity in ideal and leakage-error-corrected conditions, significant discrepancies arise without such corrections, suggesting limitations in current infidelity definitions. This thesis emphasizes the necessity of refining RB protocols to better align with realistic quantum noise environments, particularly focusing on their application within superconducting qubit systems. Future research should focus on validating these protocols experimentally and exploring their effectiveness across multi-qubit configurations to ensure accurate system characterization.