Hunting Ghosts with Rare Isotope Doped Quantum Sensors

Speaker: Kule Leach
Affiliation: Colorado School of Mines
Date: 10/02/25

Abstract: 
Nuclear beta and electron-capture decays provide exceptionally clean laboratories for testing the weak interaction and searching for new physics. Over the past several years, we have pioneered a set of research programs that embed exotic radioisotopes directly into thin-film superconducting tunnel junctions (STJs) to measure the tiny recoil “kick” an atom receives when a neutrino is emitted. These recoils encode fundamental information about the decay—sensitivity to new neutrino masses and mixings, possible non-standard weak currents, and feebly coupled dark-sector particles produced within the decay energy window. Because the approach relies on final-state kinematics, it offers a complementary and, crucially, model-independent portal to new physics, enabling synergy between laboratory measurements and cosmology. In this talk, I will present recent results from our program and the cross-disciplinary advances that make them possible—spanning subatomic physics, quantum engineering, atomic theory, and materials science. I’ll also preview next-generation efforts that harvest macroscopic quantities of exotic atoms and confine them in optically levitated nanospheres, opening a path to direct momentum measurements of nuclear-decay recoils with unprecedented precision.