Investigating the impact of magnetic fields on superconducting qubits and 3D superconducting radio-frequency cavities for quantum applications

Superconducting niobium is a fundamental material in the realm of advanced quantum technologies, required for the development of 2D qubit chips and 3D superconducting RF cavities. As a type-II superconductor, niobium is sensitive to trapped magnetic flux, which can result in significant energy losses and degrade device functionality. ​This study investigates the complex relationship between applied magnetic fields and the operational effectiveness of superconducting qubits and SRF cavities, which are critical for quantum applications.​ Employing Helmholtz coils, we generate magnetic fields of varying strengths and systematically apply them to qubit chips and cavities housed within a dilution refrigerator at cryogenic temperatures. Our analysis quantitatively assesses the impact of magnetic flux on key performance metrics, revealing essential correlations between external magnetic conditions and device efficacy. This research not only enriches our understanding of how magnetic fields affect superconducting devices but also sets the stage for optimizing performance in superconducting quantum circuits.