Characterizing supercurrent noises using superconducting CPW resonators

A detailed characterization of supercurrent noise in nanoscale Josephson junctions is crucial for advancing both foundational understanding of superconductivity and the optimization of quantum electronic systems. In such junctions, microscopic fluctuations in the supercurrent provide valuable insights into the dynamics of Cooper pair transport and the effects of microscopic defects. However, direct measurements of such noise present significant experimental challenges.

In this talk, we present a methodology for investigating Josephson current noise by integrating a Josephson junction into a superconducting coplanar waveguide resonator. By performing high sensitivity measurements of the frequency noise in the microwave domain, we extract the spectral characteristics of the underlying current fluctuations. This method provides a minimally invasive and high-bandwidth technique for probing supercurrent noise in ultra-small junctions as a valuable tool for investigating microscopic dissipation mechanisms and noise sources in superconducting circuits, with implications for quantum technologies.