Detecting dark domain walls through their impact on particle trajectories in tailored ultrahigh vacuum environments

Light scalar fields, with double well potentials and direct matter couplings, undergo density driven phase transitions, leading to the formation of domain walls. Such theories could explain dark energy or dark matter or source the nanohertz gravitational-wave background. We describe an experiment that could be used to detect such domain walls in a laboratory environment, solving for the scalar field profile and showing how the domain wall affects the motion of a test particle. We find that, in currently unconstrained regions of parameter space, the domain walls leave detectable signatures. Published by the American Physical Society 2024