2025/11/11 by D. -M. Mei, Mei, D. -M., N. Budhathoki +13 · 1 citation
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Atomic and Subatomic Physics Research #Quantum, superfluid, helium dynamics
paper · pdf · doi:10.48550/arxiv.2511.08329
We present a germanium phonon-to-charge transducer that integrates a slow-phonon phononic-crystal (PnC) region with radio-frequency quantum point-contact (RF-QPC) readout at 4 K, and we evaluate its dark-sector reach. A calibrated signal-collection model, which combines geometric guiding, propagation survival, and multiplicity-assisted primary-phonon detection, provides selection-corrected thresholds in the 10-3-10-2~eV range and a background model informed by nanosecond timing gates and GHz-band power-spectral-density windows. Under standard halo assumptions, a 100 g module achieves projected sensitivity to DM-electron and DM-nucleon scattering at recoil energies below 10-2~eV, probing cross sections below 10-43 cm2 for mχ∈ [0.01,100]~MeV/c2 (with efficiencies and thresholds folded in). We present sensitivities for both heavy-mediator (F\rm DM=1) and light-mediator (F\rm DM∝ 1/q2) benchmarks, quantify dominant systematics (threshold, phonon quality factor Q, and bulk defect densities), and outline a staged program toward kg⋅yr exposures that begins to test models approaching the solar CEνNS background.