Speaker
Description
The Superconducting Quasiparticle-Amplifying Transmon (SQUAT) is a sensor architecture targeting meV (THz) detection based on a weakly charge-sensitive transmon qubit directly coupled to a transmission line. Energy depositions in the qubit capacitor generate quasiparticles that tunnel across the Josephson junction. Each tunnel changes the qubit parity and produces a measurable signal in CW transmission. SQUATs use junctions with lower Tc than their capacitors to induce quasiparticle trapping near the junction and amplify the tunneling rate for a given energy deposition. Their enhanced sensitivity to quasiparticle events and intrinsic multiplexability make SQUATs a promising detector foundation for low-energy-threshold rare-event searches. In this talk, I will give an update on the SQUAT development program. I will present the design, characterization, and background sources influencing parity-switching rates. I will also discuss progress towards a position-dependent energy calibration using MEMS-based cryogenic optical beam steering.