2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/21646We propose a method for characterising the energy level structure of a solid-state qubit by monitoring the noise level in its environment. We consider a model persistent-current qubit in a lossy resevoir and demonstrate that the noise in a classical bias field is a sensitive function of the applied field.3 FiguresSuperconductivityQuantum Physicstext