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.
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.
Recent advancements in space science and technologies offer exciting prospects for investigating novel research that is unattainable within terrestrial laboratories. Here we propose the implementation of space-based quantum sensing to explore ultralight new particles beyond the standard model. The central idea involves probing long-range interactions between spin ensembles of space quantum sensors and the particles residing within Earth, mediated by ultralight particles. We show that such interactions can be substantially enhanced in space platforms and thus increase the search sensitivity. In contrast to their terrestrial counterparts, space-based quantum searches exhibit remarkable velocity enhancements, approaching the first cosmic speed, and thus enables the exploration of unexplored parameter space concerning ultralight new particles. Furthermore, the substantial abundance of electrons and nucleons within Earth plays a crucial role in extending the scope of our mission. Our projected search sensitivity can surpass the sensitivities of both terrestrial experiments and proposals by up to approximately 7 orders of magnitude. We also briefly discuss other space mission, including ``space-ground integrated" network of quantum sensors for dark matter searches.
Axions are a compelling dark matter candidate suggested by theories beyond the Standard Model. The predicted axion-electron coupling and the resulting pseudomagnetic field allow for laboratory axion searches. Here we report an experimental axion search via a superconductor-spin hybrid magnetometer. A state-of-the-art broadband magnetometer with a sensitivity of sub-100 aT/Hz1/2 at tens of kHz has been realized by coupling a ferrite spin sensor to a readout system based on a superconducting quantum interference device. The most stringent terrestrial constraints on the axion-electron coupling have been established in the frequency range 5$\sim$60 kHz. In the future, an improvement on the constraints of more than 4 orders of magnitude is foreseeable through arrays of superconductor-spin hybrid magnetometers with optimized designs. This work demonstrates the potential of superconductor-spin hybrid magnetometers in high-precision magnetic field sensing and the study of fundamental physics.
The applications of spin-based quantum sensors to measurements probing fundamental physics are surveyed. Experimental methods and technologies developed for quantum information science have rapidly advanced in recent years, and these tools enable increasingly precise control and measurement of spin dynamics. Theories of beyond-the-Standard-Model physics predict, for example, symmetry violating electromagnetic moments aligned with particle spins, exotic spin-dependent forces, coupling of spins to ultralight bosonic dark matter fields, and changes to the local environment that affect spins. Spin-based quantum sensors can be used to search for these myriad phenomena, and offer a methodology for tests of fundamental physics that is complementary to particle colliders and large scale particle detectors. Areas of technological development that can significantly enhance the sensitivity of spin-based quantum sensors to new physics are highlighted.
One of the areas of research of the Superconducting Quantum Systems and Materials (SQMS) center is the application of quantum sensing to fundamental physics searches, demonstrating that quantum sensors can greatly improve the sensitivity of experiments searching for Beyond the Standard Model (BSM) physics, or performing high-precision measurements. Theorists have developed many ideas for BSM physics that would result in interactions that can in principle be detected, but with signals small enough that they haven t been observed yet. In this field, the capability to lower the detector s thermal noise to few or dozens of mK, and to use QIS technologies such as Josephson Parametric Amplifiers and photon counters (in-situ or itinerant) enable us to reach unprecedented sensitivities and faster scan rates. Here is presented an overview of the quantum sensing efforts at SQMS [1], focusing on theoretical advancements and experimental searches for Dark Sector particles (as dark matter candidates and not), gravitational waves, and precision measurements. The experiments conducted, or under preparation, include axion dark matter (DM) [2, 3], dark photon DM searches [4,5], light-shining-through-wall experiments [6], cavity-based searches for high frequency gravitational waves [7], and measurements of the electron magnetic moment [8]. [1] Berlin, A., et al. "Searches for new particles, dark matter, and gravitational waves with SRF cavities." arXiv preprint arXiv:2203.12714 (2022). [2] Giaccone, B., et al. "Design of axion and axion dark matter searches based on ultra high Q SRF cavities." arXiv preprint arXiv:2207.11346 (2022). [3] Braggio, C., et al. "Quantum-enhanced sensing of axion dark matter with a transmon-based single microwave photon counter." arXiv preprint arXiv:2403.02321 (2024). [4] Fan, X., et al. "One-electron quantum cyclotron as a milli-eV dark-photon detector." Physical review letters 129.26 (2022): 261801. [5] Cervantes, R., et al. "Deepest sensitivity to wavelike dark photon dark matter with superconducting radio frequency cavities." Physical Review D 110.4 (2024): 043022. [6] Romanenko, A., et al. "Search for dark photons with superconducting radio frequency cavities." Physical review letters 130.26 (2023): 261801. [7] Berlin, A., et al. "Electromagnetic cavities as mechanical bars for gravitational waves." Physical Review D 108.8 (2023): 084058. [8] Fan, X., et al. "Measurement of the electron magnetic moment." Physical review letters 130.7 (2023): 071801.
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.