  Searching for physics beyond the standard model is crucial for understanding
the mystery of the universe, such as the dark matter. We utilized a single spin
in a diamond as a sensor to explore the spin-dependent interactions mediated by
the axion-like particles, which are well motivated by dark matter candidates.
We recorded non-zero magnetic fields exerted on the single electron spin from a
moving mass. The strength of the magnetic field is proportional to the velocity
of the moving mass. The dependency of the magnetic field on the distance
between the spin and the moving mass has been experimentally characterized. We
analyzed the possible sources of this magnetic signal, and our results provide
highly suggestive of the existence of a new spin-dependent interaction. Our
work opens a door for investigating the physics beyond the standard model in
laboratory.
