We present a novel approach to detect millicharged dark matter (mDM) by using a high-sensitivity magnetometer coupled with the resonant and broadband readout circuits. In the external magnetic field, the interaction between mDM and the photon field introduces an effective current corresponding to the mDMs annihilation into photons that produces a faint oscillating magnetic field signal, with a frequency uniquely determined by twice the mDM mass. By calculating the expected signal for two experimental configurations -- toroidal and solenoidal magnetic fields -- we show the potential to explore the uncharted regions of mDM parameter space. Our analysis establishes unprecedented constraints on the mDM coupling constant across the mass range 1×10−12eV to 6×10−8eV, surpassing existing experimental limits by more than ten orders of magnitude.
@article{arxiv.2504.09630,
title = {Probing Millicharged Dark Matter with Magnetometer Coupled to Circuit},
author = {Yuanlin Gong and Hongliang Tian and Lei Wu and Bin Zhu},
journal= {arXiv preprint arXiv:2504.09630},
year = {2025}
}