An Introduction to Double String Theory and Non-Riemannian Backgrounds

Abstract: This talk introduces Double Field Theory (DFT) in the context of string theory, with a focus on its application to "non-Riemannian" backgrounds following arXiv:2008.03084. As a case study, we consider a particular example in which the BRST cohomology simplifies, containing only states at the first excited level. We then briefly examine the consistency of the theory by analyzing the modular invariance of the one-loop torus partition function. To keep the discussion pedagogical, a brief review of BRST quantization and modular invariance in string theory will be provided. No prior familiarity with DFT is assumed, and all are welcome.

condensed mattergeneral relativity and quantum cosmologyHEP - theorymathematical physicsdifferential geometry

Audience: advanced learners

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Europe and Pacific Theoretical Physics

Series comments: European and Pacific Theoretical Physics is a group that runs online seminars and talks across broad topics in mathematical and theoretical physics. Our goal is to share concepts across continents to bring about a deeper understanding of cutting-edge topics in physics.

The talks are informal, and anyone can participate, so please reach out if you would like to present one week!

Extended notes & presentation material are uploaded to "Past talks". Please click on the title of a talk, and then click on "paper" or "slides" to see more. Our focus for 2025 was on Generalised (Categorical) Symmetries, following the lecture notes found here: arxiv.org/pdf/2411.09082.

The reading course seminars are scheduled to resume in 2026. If you would like to present material, please reach out.

Zoom link: unibe-ch.zoom.us/j/6801537904

Talks may be uploaded to YouTube: www.youtube.com/@eupactp

Mailing list sign-up: forms.gle/StswcjC7RbXWuvAr8

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