[NTU-NCTS String Seminar] A universal cutoff for field theory with gravity

  • Event Date: 2024-08-28
  • High energy theory
  • Speaker: Dr. Yue-Zhou Li (Princeton U.)  /  Host: Prof. Chia-Hsien Shen
    Place: Online (Zoom)

Title：A universal cutoff for field theory with gravity
Speaker：Dr. Yue-Zhou Li (Princeton U.)
Date：2024/07/28 (Wed.)
Time：09:00 AM

Zoom Link:
https://us06web.zoom.us/j/83468875457?pwd=eQ0rK02UyaScvyRkqEKhNeybAnGqbo.1
 
Abstract：
There is a longstanding argument that local field theory with gravity must break down at the species scale, which is much lower than the Planck scale by the number of species. We aim to improve the understanding of this statement. We analyze the one-loop effects of massive fields on the graviton scattering and use the analyticity and unitarity to provide numerical species bounds for light species. Around the scale where the field theory breaks down, we instead analyze the partial waves and observe that possible UV scenarios with gravity, such as string theory, all exhibit significant high-spin contents. This motivates a concept "high-spin onset scale", which qualitatively coincides with string scale or higher dimensional Plank scale, depending on the UV scenarios. The suggestion is that the high-spin onset scale is a universal cutoff for field theory, beyond which the local field description should not exist.

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