Guanjun Xu, Ph.D., is a research fellow currently employed at the National Time Service Center of the Chinese Academy of Sciences. His primary research focuses on ultra-stable optical cavities, gravitational wave detection, dark matter theory and detection, Brownian thermal noise theory, and ultra-stable lasers and their applications. He has been awarded the Shaanxi Provincial Outstanding Youth Science Fund and serves as the chief scientist of the "Scientist + Engineer" team of the Qin Chuang Yuan in Shaanxi Province. He is also a member of the Youth Innovation Promotion Association of the Chinese Academy of Sciences. He has presided over more than 10 provincial and national projects, including the Shaanxi Natural Science Fund and the National Natural Science Fund.