The University of Science and Technology of China has made a series of important progress in the study of novel spin interactions

By using nitrogen-vacancy color centers in diamond as solid-state spin quantum sensors, Du Jiangfeng's team at the Key Laboratory of Micromagnetic Resonance of the Chinese Academy of Sciences of the University of Science and Technology of China conducted experimental searches for a series of novel spin interactions at the microscopic scale and proposed new experimental limits.

The relevant research results have been published in National Science Review 10, nwac262 (2023), Physical Review Letters [Phys. Rev. Lett. 131, Phys. And Proceedings of the National Academy of Sciences [Proc.Natl.Acad.Sci.120, e2302145120 (2023)].

In July, the results of the study, "New constraints on exotic spin-dependent interactions with an ensemble-NV-diamond magnetometer," were published in the National Science Review.

Original link：

https://academic.oup.com/nsr/article/10/7/nwac262/6832283?login=false

On August 15th, the result is "Improved Limits on an Exotic Spin- and Velocity-Dependent Interaction at the Micrometer Scale with an. Ensemble-NV-Diamond Magnetometer, "in the journal Physical Review Letters.

Original link：

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.071801

The results, titled "A spin-mechanical quantum chip for exploring exotic interactions," were published August 28 in the Proceedings of the National Academy of Sciences.

Original link：

https://www.pnas.org/doi/10.1073/pnas.2302145120

Further enhance the search capability of quantum sensors

Exploring new physical phenomena beyond the Standard Model can help answer fundamental questions that cannot be explained by the Standard Model, such as the strong CP puzzle and the physical nature of dark matter and dark energy. In recent years, the experimental search for some novel spin interactions induced by new bosons has become the focus of research.

In 2018, Du Jiangfeng's team originally proposed to construct the single-electron spin of diamond nitrogen-vacancy (NV) color center as a quantum sensor, which can be used to search for novel spin interactions between electrons and nuclei. And the force range of the experimental search is successfully extended to the submicron scale [Nature Communications 9, 739 (2018)]. Subsequently, a series of spin interactions were experimentally searched at the microscopic scale with high precision [Physical Review Letters 121, 80402 (2018),Physical Review Letters 127, 010501 (2021)].

In order to further improve the search capability, the team is advancing in two directions: 1) to develop more sensitive sensors for higher accuracy experimental inspection; 2, develop a new form of sensor, open a shorter force range of the detection window.

Search for novel spin at the microscopic scale

In order to achieve a higher sensitivity sensor, the team implemented a high-quality diamond NV ensemble electron spin growth process, upgraded the single spin detector to a ensemble spin sensor, so that more NV color centers can be used for measurement at the same time, greatly improving the detection accuracy. Thus, experimental search for a series of novel spin interactions can be realized [National Science Review 10, nwac262 (2023),Phys. Rev. Lett. 131, 071801 (2023)].

On the other hand, the team made full use of the advantages of a single NV color center as an atomic-scale sensor, combining MEMS technology and silicon-based nanoprocesses to achieve a scalable spin-mechanical quantum chip. Experiments show that the chip improves the observation constraint by 2 orders of magnitude at force ranges less than 100 nm [PNAS120,e2302145120 (2023)]. These results demonstrate the unique advantages of using diamond NV color center spin quantum sensors to study a variety of new physics beyond the standard model, and are expected to stimulate a wide range of fundamental sciences such as cosmology, astrophysics and high energy physics.

This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology, Anhui Province, and the National Natural Science Foundation of China.