Numerous theories beyond the standard model predict the existence of exotic bosons that could serve as candidates for dark matter. Here we present the Space-based Quantum Sensing for Interaction and Exotic Bosons Research Exploration scheme, along with a demonstration of a prototype space quantum sensor designed for near-future space experiments. The core concept involves probing exotic-boson-mediated spin-spin-velocity interactions between the spins within space quantum sensors and the electrons within the Earth. Unlike terrestrial counterparts, our space-based searches benefit from the significantly increased velocity provided by the orbital motion of the space quantum sensors around the Earth, which approaches the first cosmic speed. Additionally, the substantial abundance of polarized electrons within the Earth also enhances the scope of our mission. We demonstrate that our prototype space quantum sensor can suppress geomagnetic interference in space by 12 orders of magnitude, achieving a single-shot sensitivity of 4.3 fT in the sub-mHz regime. This illustrates the feasibility of conducting exotic-boson searches in the challenging space environment. As a result, the search sensitivity for such exotic interactions can be significantly enhanced by up to approximately 7 orders of magnitude compared to both terrestrial experiments and proposals. This work opens up a novel approach for searching for new physics, including space-based axion-halo searches and
CPT violation probes.
We present a magnetically levitated ferromagnetic vector force sensor that enables selective searches for spin-dependent exotic interactions mediated by beyond-Standard-Model bosons. A defining feature of spin-dependent exotic interactions is that they can generate forces with distinct directional signatures set by the relative spin configuration of the interacting bodies. We show that our sensor resolves these signatures by mapping forces along different axes onto distinct translational modes with different resonance frequencies, thereby separating interaction channels within the same coupling class. As a representative example, we study parity-violating axial-vector--vector interactions mediated by a spin-1
Z′ boson between a sensing and a driving levitated ferromagnet. Using a matched-filter likelihood analysis, we show that a setup based on an already demonstrated experiment can probe the pure electron--electron coupling
gAegVe in the previously inaccessible force range
λ≲1cm, corresponding to mediator masses
MZ′≳10−5eV/c2. Our results establish levitated ferromagnets as a promising platform for millimeter-scale searches for spin-dependent fifth forces and for resolving the multiple effective potentials associated with a given coupling class.
The excellent sensitivities of quantum sensors are a double-edged sword: minuscule quantities can be observed, but any undesired signal acts as noise. This is challenging when detecting quantities that are obscured by such noise. Decoupling sequences improve coherence times and hence sensitivities, though only AC signals in narrow frequency bands are distinguishable. Alternatively, comagnetometers operate gaseous spin mixtures at high temperatures in the self-compensating regime to counteract slowly varying noise. These are applied with great success in various exotic spin-interaction searches. Here, we propose a method that decouples specific DC fields from DC and AC magnetic noise. It requires any spin cluster where the effect on each individual spin is different for the target field and local magnetic fields, which allows for a different approach compared to comagnetometers. The presented method has several key advantages, including an orders-of-magnitude increase in noise frequencies to which we are resistant. We explore electron-spin nuclear-spin pairs in nitrogen-vacancy centres in diamond, with a focus on their merit for light dark-matter searches. Other applications include gradient sensing, quantum memory, and gyroscopes.