Response of Comagnetometer to Exotic Spin-Dependent Couplings

TL;DR

This paper investigates how comagnetometers respond to exotic spin-dependent interactions, providing analytical models, calibration methods, and revised techniques to enhance their sensitivity in dark matter detection.

Contribution

It offers the first combined theoretical and experimental analysis of comagnetometer frequency response to exotic couplings, including calibration protocols and improved measurement methods.

Findings

Derived analytical expressions for frequency response to exotic interactions

Revised method for determining axion-nucleon coupling strength

Introduced a light-shift-based calibration protocol

Abstract

Comagnetometers offer unique advantages in measuring exotic spin-dependent interactions by suppressing magnetic noise. Understanding the frequency response to exotic interactions is essential for evaluating and improving the sensitivity of comagnetometers, as the signals often exhibit distinct spectral features. We conduct theoretical and experimental studies on the frequency response of a differential comagnetometer. We derive analytical expressions for the frequency response of the differential comagnetometer to both magnetic field and exotic couplings, along with the conversion relationship between them. Based on this, we revise the method for determining the axion-nucleon coupling strength with comagnetometers. Furthermore, we introduce a light-shift-based calibration protocol to verify the response to exotic interactions. This work helps predict the sensitivity of comagnetometers in detecting exotic fields and advances the exploration of dark matter.