A Rotating-Wave Comagnetometer Detector for Particle Physics

Many extensions of the Standard Model propose the existence of new particles or forces, aiming to answer mysteries such as the identity of the elusive dark matter. Atomic-based detectors are at the forefront of technologies designed to search for these particles or forces through their couplings to fermions, enabling the testing of well-motivated models, such as axion-like particles, which could form dark matter. These detectors also probe new long-range interactions between the detectors and spin-polarized objects, as well as interactions mediated by light particles that break CP symmetry, introducing a coupling between the detector and an unpolarized object. However, the sensitivity of these detectors is often constrained by magnetic noise, limiting their effectiveness to a narrow region of parameter space. We propose and develop a technique, which we name the Rotating Wave comagnetometer (RoW comag), that can suppress magnetic noise at tunable frequencies while maintaining high sensitivity to target signals, significantly expanding the potential reach of these detectors. We analyze its operation for testing various extensions to the Standard Model and show how it could improve current sensitivities by several orders of magnitude. This work paves the way for a new class of tabletop experiments aimed at searching for new physics, including the exploration of well-motivated axion-like particle dark matter models at higher masses than previously attainable.