Quantum Charge Parity Detectors with meV Resolution for Astroparticle Applications*

Sub-eV threshold particle detectors are an area of burgeoning interest, driven in part by needing to probe the increasingly theoretically relevant sub-GeV mass dark matter parameter space. One such promising technology 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 < 10^-20 W/√Hz. We seek to extend the applicability of this technique 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 quasiparticles (broken Cooper-pair electrons) within the superconducting absorber, as produced by single meV phonons. In this talk we will discuss preliminary charge-parity detector design progress and challenges and lay out a roadmap for demonstrating eV and subsequently lower energy resolution.