Searching for Exotic Spin-Dependent Interactions with Diamond-Based Vector Magnetometer

Abstract

We propose a new method to search for exotic spin-spin interactions between electrons and nucleons using a diamond-based vector magnetometer. The vector magnetometer can be constructed from ensembles of nitrogen-vacancy centers along different axes in a diamond. The ${}^{14}\mathrm{N}$ nuclear spins of nitrogen-vacancy centers in the same diamond can be polarized through the dynamic nuclear polarization method to serve as spin sources. With the vector magnetometer, the sought-after exotic interactions can be distinguished from the magnetic dipole-dipole interaction. For the axion-mediated interaction $V_{PP}$, new upper bounds of the coupling $|g_P^e{g}_P^N|$ are expected within the force range from 10 nm to 100 $\mu$m. For the $Z^{\prime }$-mediated interaction $V_{AA}$, new upper bounds of the coupling $|g_A^e{g}_A^N|$ are expected within the force range from 10 nm to 1 cm. The new upper bounds for $V_{PP}$ and $V_{AA}$ are both expected to be more than 5 orders of magnitude more stringent than existing constraints at the force range of 1 $\mu$m with the total measurement time of one day.