Response of atomic spin-based sensors to magnetic and nonmagnetic perturbations

TL;DR

This paper compares SERF magnetometers and noble-gas-alkali-metal co-magnetometers, demonstrating the latter's superior response to pseudo-magnetic couplings and its potential for detecting exotic physics phenomena.

Contribution

The study introduces a self-compensating co-magnetometer that reduces magnetic sensitivity while enhancing detection of pseudo-magnetic interactions.

Findings

Co-magnetometer shows five orders of magnitude stronger response to neutron pseudo-magnetic coupling.

Co-magnetometer exhibits three orders of magnitude stronger response to proton pseudo-magnetic coupling.

Different frequency responses enable differentiation between magnetic and nonmagnetic perturbations.

Abstract

Searches for pseudo-magnetic spin couplings require implementation of techniques capable of sensitive detection of such interactions. While Spin-Exchange Relaxation Free (SERF) magnetometry is one of the most powerful approaches enabling the searches, it suffers from a strong magnetic coupling, deteriorating the pseudo-magnetic coupling sensitivity. To address this problem, here, we compare, via numerical simulations, the performance of SERF magnetometer and noble-gas-alkali-metal co-magnetometer, operating in a so-called self-compensating regime. We demonstrate that the co-magnetometer allows reduction of the sensitivity to low-frequency magnetic fields without loss of the sensitivity to nonmagnetic couplings. Based on that we investigate the responses of both systems to the oscillating and transient spin perturbations. Our simulations reveal about five orders of magnitude stronger response to the neutron pseudo-magnetic coupling and about three orders of magnitude stronger response to the proton pseudo-magnetic coupling of the co-magnetometer than those of the SERF magnetometer. Different frequency responses of the co-magnetometer to magnetic and nonmagnetic perturbations enables differentiation between these two types of interactions. This outlines the ability to implement the co-magnetometer as an advanced sensor for the Global Network of Optical Magnetometer for Exotic Physics searches (GNOME), aiming at detection of ultra-light bosons (e.g., axion-like particles).