报告题目 (Title)：O(D,D) string cosmology from double field theory

（双场理论下的O(D,D)弦宇宙学）

报告人 (Speaker)：Dr. Stephen Angus（韩国西江大学）

报告时间 (Time)：2025年9月24日(周三) 10:00-11:40

报告地点 (Place)：校本部 AJ204

邀请人 (Inviter)：尹璐

主办部门：理学院物理系

摘要 (Abstract)：

The low-energy limit of string theory contains additional gravitational degrees of freedom that are not present in general relativity. Together with the metric, these fields are naturally embedded in the O(D,D)-symmetric framework of double field theory (DFT). First I will explain how the O(D,D) symmetry uniquely prescribes the interactions between the extended gravitational sector and other matter, leading to novel features beyond conventional string cosmology. Then I will present the equations of motion for linear perturbations, and I will show how the generalized conservation laws modify the conditions for conservation of curvature perturbations. Finally, I will present some examples of analytic solutions, including candidate models for bouncing cosmologies, and I will explore how they may imply a non-Riemannian origin of the universe.