There are a number of sources of noise that impinge on superconducting qubits, with corresponding strategies of amelioration. For example, thermal photons are reduced by cooling the devices in a dilution refrigerator and heavily attenuating and filtering the control lines; ionising radiation can be shielded by moving underground. However, despite these efforts, noise continues to drive unwanted processes in qubits. Fluxonium is a superconducting qubit whose rich Hamiltonian structure enables a broad range of attainable device parameters. This makes it a promising candidate for metrology of noise in its environment.

Superconducting resonators can store quantum information for longer than the best Josephon junction-based qubits. They also posess a large Hilbert space that allows for more hardware-efficient bosonic encodings, which have demonstrated error correction beyond break-even. However, current devices have either a small number of resonators, or suffer from significant coherence losses compared to state-of-the-art devices. I am interested in mitigating the trade-off by leveraging the understanding of sources of decoherence to develop more scalable devices with reduced losses.

Reducing material losses is crucial to improving superconducting qubit and resonator coherences. To date, the microscopic mechanisms behind these losses remain poorly understood, leading to a reliance on trial-and-error in fabrication and material selection. Despite recent work using traditional material characterisation methods, establishing clear causal relationships with coherence, the critical metric for device performance, has proven elusive. I am interested in developing systematic techniques to address this challenge, such as engineering devices capable of isolating different loss mechanisms and using them to identify proxies for microwave losses within conventional material characterisation methods.