Speaker
Description
Next generation "sub-GeV" dark matter searches require new tools and techniques with much improved sensitivity. In particular, the constrained kinematic space of potential interactions suggests that collective excitations like phonons may be the only signature of very low mass dark matter candidates. One promising technology to study these are qubit derived superconducting charge-parity sensors. These detection schemes include Quantum Capacitance Detectors (QCDs) and Offset-Charge Sensitive (OCS) devices, and the former have been demonstrated in previous literature as excellent far-IR photon counters with NEP of <1E-20 W/√Hz. We seek to extend the applicability of these techniques by directly coupling the sensors to interaction induced athermal phonons generated within a crystalline silicon substrate. Such a scheme will enable the literal counting of O(100) ueV quasiparticle quanta (broken Cooper-pair electrons) within a superconducting absorber, as produced by single meV phonons. In this presentation, we will discuss early results demonstrating a working charge-parity detector design, and lay out a roadmap for eV and subsequently lower energy resolution in future iterations.
