Ultrasensitive Calorimetry in an Al/InAs Josephson Junction

Calorimetry allows for the detection of single-shot energy pulses over a wide bandwidth. Pushing the limits of energy resolution to the yoctojoule (1e-24 J) regime would allow detection of individual thermal phonons and monitoring of dynamics in open quantum systems. We present work toward development of a Josephson junction-based calorimeter fabricated from an Al/InAs superconductor-semiconductor heterostructure, a material system being developed for scalable topological quantum computation. Ongoing work seeks to demonstrate a device proof-of-principle while simultaneously characterizing fundamental thermal properties of this material system.