Speaker
Description
The nature of dark matter remains one of the pivotal questions in physics. To date, large-scale direct detection experiments have primarily focused on weakly interacting massive particles with masses above the GeV scale, leaving much of the eV–GeV mass range comparatively unexplored. This motivates the development of alternative detection strategies capable of probing sub-GeV dark matter, where qualitatively different experimental approaches are required. Optically levitated nanoparticles provide a promising platform for this purpose, offering ultra-low energy thresholds and a highly tunable mechanical response, enabling sensitivity to a wide range of potential dark matter interactions.
In this work, we present a phenomenological study of levitated optomechanical sensors operated at optimal sensitivity, and use this framework to project the reach of a table-top experiment based on a single levitated nanoparticle. By systematically accounting for the dominant noise sources: thermal decoherence, photon recoil, and quantum backaction, we identify the experimental configurations that maximise sensitivity using a newly developed computational framework.
We derive projected exclusion limits for several dark matter candidates, including standard spin-independent scattering as well as long-range Yukawa interactions relevant for composite and extended dark matter scenarios. We find that for spin-independent scattering, levitated sensors can achieve sensitivity competitive with existing constraints in the sub-GeV mass range and, for long-range Yukawa interactions, can achieve sensitivity beyond current experimental constraints. These results highlight the substantial and largely unexplored potential of levitated optomechanical systems as a versatile probe of sub-GeV dark matter phenomenology.