Speaker
Description
We present a novel framework to search for dark matter (DM) through its electromagnetic (EM) signatures in the terrestrial environment. Ultralight DM candidates, such as axions and dark photons, can induce nearly monochromatic EM fields via their coupling to ordinary photons. In the presence of the geomagnetic field, axion DM induces extremely low-frequency EM signals in the Earth–ionosphere cavity, with spectral features shaped by atmospheric conductivity and resonances. We develop a semi-analytical framework to predict these signals and compare them with geoscience data sets to place new constraints. We further extend this approach to dark photon DM, highlighting both similarities and key differences. These results establish terrestrial EM fields as a powerful and complementary probe of ultralight DM.