Fig. 2: Spectroscopy of defect resonance frequencies in dependence of the applied global electric field (segments with red borders) and the mechanical strain (blue frames).
From: Probing defect densities at the edges and inside Josephson junctions of superconducting qubits
Dark traces indicate reduced qubit T1 time due to resonance with a defect. The colored shadings indicate defect locations listed in the legend. Note that in a, a defect in the small junction is observed, whose large coupling strength affects the qubit coherence in a wide band. Apparently, a shift of its asymmetry energy occurred during measurement (see dashed arrow), which illustrates how defects can spontaneously (dis)appear in the qubit’s spectrum. The strain-tunability statistics of defects detected in Josephson junctions are analyzed in another work52.
