New spin experiments could rewrite physics textbooks

Researchers have used quantum sensors to explore new particle interactions at microscopic distances, providing groundbreaking results that expand the scope of the Standard Model in physics.

A research team led by Academician Du Jiangfeng and Professor Rong Xing from the University of Science and Technology of China (USTC), part of the Chinese Academy of Sciences (CAS), in collaboration with Professor Jiao Man from Zhejiang University, used solid-state spin quantum sensors to examine dependent exotic interactions. On rotation speeds (SSIVDs) in short power ranges. Their study reported new experimental results related to the interactions between the spins of electrons and was published in Physical Review Letters.

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

Some theories suggest that new particles could act as distributors, transmitting new interactions between Standard Model particles. At present, there is a lack of experimental research on new velocity-related interactions between spins, especially in the relatively small force-distance range, where experimental verification is almost nonexistent.

Experimental results of the study. Source: Du et al.

Experimental setup and methodology

The researchers designed an experimental setup with two diamonds. A high-quality nitrogen vacancy (NV) cluster was prepared on the surface of each diamond using chemical vapor deposition. One electron spin in the NV cluster acts as a spin sensor, while the other acts as a spin source.

The researchers looked for new interaction effects between the velocity-dependent spin of electrons on the micrometer scale by coherently manipulating the spin quantum states and relative velocities of two diamond NV clusters. First, they used a spin sensor to characterize the interaction of a magnetic dipole with a spin source as a reference. Next, by modulating the vibration of the spin source and performing locking detection and orthogonal phase analysis, they measured the SSIVDs.

For two new interactions, the researchers made the first experimental detection in the strength range of less than 1 cm and less than 1 km, respectively, and obtained valuable experimental data.

As the editor notes, “The results bring new insights to the quantum sensing community for exploring fundamental interactions that exploit the compact, flexible, and sensitive features of solid-state spin.”

Reference: “New constraints on spin-dependent exotic interactions with solid-state quantum sensors” by Yu Huang, Hang Liang, Man Jiao, Bai Yu, Xiangyu Ye, Yijin Xie, Yi-Fu Kai, Chang-Kui Duan, Ya Wang, Xing Rong, and Jiangfeng Du, April 30, 2024, Physical Review Letters.
DOI: 10.1103/PhysRevLett.132.180801