We theoretically predict and experimentally observe the onset of weak-link physics in the dynamical response of transition edge sensors (TES). We develop a theoretical framework based on a Fokker-Planck description that incorporates both the TES electrical response, stemming from Josephson phenomena, and the electrothermal effects due to coupling to a thermal bath. Our measurements of a varying dynamic resistance are in excellent agreement with our theory, thereby establishing weak-link phenomena as the main mechanism underlying the operation of TES. Furthermore, our description enables the calculation of power spectral densities, paving the way for a more thorough investigation of the unexplained "excess noise" in long diffusive junctions and TES reported in recent experiments.
@article{arxiv.2212.06443,
title = {Demonstration of Weak-Link Physics in the Dynamical Response of Transition-Edge Sensors},
author = {Marios Kounalakis and Luciano Gottardi and Martin de Wit and Yaroslav M. Blanter},
journal= {arXiv preprint arXiv:2212.06443},
year = {2023}
}