The study suggests new constraints on spin-spin-momentum-dependent extrinsic interactions between electron spins.

A team of researchers has used solid-state spin quantum sensors to probe spin-spin-velocity-dependent extrinsic interactions (SSIVDs) in short energy ranges, reporting new experimental results between electron spins. Their work has been published in Physical Review Letters.

The Standard Model is the most successful theoretical framework in particle physics, describing elementary particles and four fundamental interactions. However, the Standard Model still cannot explain some important observations in current cosmology, such as dark matter and dark energy.

Some theories suggest that new particles can act as propagators, spreading new interactions between Normal Model particles. Currently, there is a lack of experimental research on the new speed-related interactions between cycles, especially in the small range of power distances, where experimental verification is almost non-existent.

The researchers developed an experimental setup containing two diamonds. A high concentration of nitrogen vacancy (NV) was prepared on the surface of each diamond using chemical vapor deposition. An electron circuit in one NV assembly serves as a circuit sensor, while the other acts as a circuit source.

The researchers searched for new interaction effects between the speed-dependent spins of electrons at the micrometer scale by uniformly controlling the spin quantum states and the relative speed of two diamond NV ensembles. First, they used a spin sensor to focus on the magnetic interaction of the dipole with a spin source as a reference. Then, by adjusting the frequency source vibration and performing lock detection and phase orthogonal analysis, they measured SSIVD.

For the two new interactions, the researchers conducted the first experimental observations in the power range of less than 1 cm and less than 1 km respectively, obtaining important experimental data.

As the editor stated, “The results bring new insights to the multisensory community to explore the fundamental interactions that utilize the compact, flexible, and sensitive components of solid-state circuits.”

The team was led by scholar Du Jiangfeng and Prof. Rong Xing from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), in collaboration with Professor Jiao Man from Zhejiang University.