童曦 博士学术报告
Title: A Match Made in Heaven: Linking Observables in Inflationary Cosmology
Speaker: Xi Tong (童曦)
Affiliation: University of Cambridge, UK (英国剑桥大学)
Time: 14:00-15:00, Tuesday, 3rd June, 2025 (UTC+8, Beijing Time)
Venue: Room 1502, Shing-Tung Yau Center, Yifu Architecture Building, Sipailou Campus of Southeast University, Nanjing (东南大学四牌楼校区逸夫建筑馆丘成桐中心1502室)
Inviter: Qiang Wen (文强)
Abstract
The non-Gaussian statistics of primordial perturbations is a pristine tracer of new physics in the early universe. Traditionally, different correlators are computed independently using diagrammatics given the underlying Lagrangian. However, such computations work diagram-by-diagram and are often obscured by heavy mathematics. In this talk, I will show that different correlator observables are, in fact, not independent. Rather, there exist subterranean connections among correlators that bypass the technical complexities. Starting from generic assumptions, I will establish a reality theorem which then translates to an infinite family of cutting rules linking higher-point correlators to lower-point ones. As a concrete application, I will show that the parity-odd curvature trispectrum is a precise “double copy” of the curvature-graviton mixed bispectrum whenever a gravitational Chern-Simons term is involved. Such relations are the first cosmological cutting rules that can be observationally tested and serve as a smoking gun towards physics in the primordial universe.
Speaker
Dr. Xi Tong is currently a postdoc at the University of Cambridge.