Projected ultra-heavy dark matter sensitivity of Windchime

Despite strong astrophysical and cosmological evidence, dark matter has not yet been detected in direct detection experiments. The Windchime project was formed to study and implement dark matter detectors based on large arrays of quantum-enhanced mechanical sensors to probe new parameter space that is not well-covered by existing direct detection experiments. In this work, we study two different approaches, MEMS and magnetic levitation sensors, for constructing these sensor arrays. We show that these two approaches are complementary, where magnetic levitation sensors can better cover heavier dark matter candidates with lower flux, whereas MEMS sensors can be used to make denser sensor arrays in the near-term. We further show that even with a futuristic experimental setup, probing dark matter via gravitational couplings remains extremely challenging.