Speaker
Description
One of the challenges of mesoscopic physics is calorimetric detection of microwave photons. It requires samples of ultrasmall heat capacity of order of Boltzmann constant. Here we investigate possibility of using proximitized metal for this purpose. First, we point out that the small heat capacity implies also small absorption rate. We show a trade-off between quantum efficiency of calorimetric detection and signal-to-noise ratio. The trade-off is demonstrated for mini-gap developed in proximitized metal, and the mini-gap is analysed both in terms of simple model as well as by means of Usadel equation. As a result we can obtain decent efficiency and reasonable signal-to-noise ration at the same time. Finally, the mini-gap may result in two electron temperatures (above and below mini-gap) due to small equilibration rate across the mini-gap. We propose a procedure of calibration of the thermometer in such circumstances.