How do you know if you ran through a wall?

摘要

Stable topological defects of light (pseudo)scalar fields can contribute tothe Universe's dark energy and dark matter. Currently the combination ofgravitational and cosmological constraints provides the best limits on such apossibility. We take an example of domain walls generated by an axion-likefield with a coupling to the spins of standard-model particles, and show thatif the galactic environment contains a network of such walls, terrestrialexperiments aimed at detection of wall-crossing events are realistic. Inparticular, a geographically separated but time-synchronized network ofsensitive atomic magnetometers can detect a wall crossing and probe a range ofmodel parameters currently unconstrained by astrophysical observations andgravitational experiments.