»ã±¨±êÌâ (Title)£ºO(D,D) string cosmology from double field theory

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»ã±¨ÈË (Speaker)£ºDr. Stephen Angus£¨º«¹úÎ÷½­´óѧ£©

»ã±¨¹¦·ò (Time)£º2025Äê9ÔÂ24ÈÕ(ÖÜÈý) 10:00-11:40

»ã±¨µØÖ· (Place)£ºÐ£±¾²¿ AJ204

Ô¼ÇëÈË (Inviter)£ºÒüè´

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ÌáÒª (Abstract)£º

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.