We develop superconducting sensors for detecting the tiny signals from axions. The primary technology we work on is SQUATs–Superconducting Quasiparticle-Amplifying Transmons. Energy depositions from, e.g., THz photons from axion conversion break Cooper pairs in the superconductor, generating quasiparticles (effectively single electrons). When quasiparticles tunnel across the qubit’s Josephson junction, the qubit’s parity switches. The SQUAT signal is thus an elevated parity switching rate.
Recent Sensing Publications:
A SQUAT–see the two fins that are the islands, coupled to an RF feedline (bottom) and charge line (out of frame at the top). The islands are coupled by a Josephson junction
Dolan-style Josephson junction in a SQUAT