1. Development and Applications of Levitated Ferromagnetic Sensors

Levitated systems, characterized by weak environmental coupling, have emerged as a prominent research focus in precision measurement due to their significant advantages. Our team has successfully developed a novel magnetically levitated ferromagnetic resonator sensor, achieving a sensitivity of 20 fT/√Hz at an extremely small scale (20 μm). This sensitivity is comparable to state-of-the-art SQUID sensors and atomic magnetometers but operates at a drastically reduced scale, offering superior spatial resolution and integration potential.

This magnetometer demonstrates immense potential in both fundamental research and practical applications. In fundamental physics, it can be employed to detect weak signals such as dark matter and gravitational waves. In applied fields, it enables precise measurements of material magnetism and biomagnetic signals, providing a powerful tool for materials science and life sciences. With further optimization, this sensor is expected to play a crucial role in high-precision measurement scenarios.

2. Probing New Physics with Spin-Polarized Systems

Despite its remarkable success, the Standard Model leaves several unresolved questions, such as the strong CP problem and the nature of dark matter. Dark matter research represents one of the most important frontiers in fundamental physics, with axions being a leading candidate. Axions not only potentially explain dark matter but may also resolve the strong CP problem. They are also predicted to mediate new interactions beyond the four fundamental forces (a "fifth force").

Our research group specializes in using spin-based systems to detect dark matter candidates such as axions and dark photons. We have developed a suite of precision spin-based magnetometers, including atomic magnetometers and novel levitated ferromagnetic resonator sensors. The fermion spins (e.g., neutrons, protons, electrons) in these sensors can couple with dark matter particles or detect weak magnetic fields induced by dark matter, enabling both direct and indirect detection (via fifth-force interactions).

Additionally, these advanced sensors are capable of detecting other fundamental signals, such as gravitational waves and neutrinos. Through high-sensitivity measurement techniques, we aim to push the boundaries of fundamental physics, providing new experimental tools and methods to unravel the mysteries of the universe.