Week 02.01.2022 – 08.01.2022

I shall review some key features of the three ten-dimensional string models with broken supersymmetry that are free of tachyonic modes. Their leading back-reactions are runaway “tadpole potentials”, which have important effects on their ambient spacetimes. When these are explored in detail within the low-energy effective theory, some surprising features emerge: ·Tadpole potentials can drive interesting spontaneous compactifications; ·In Cosmology, they can lead to the peculiar “climbing scenario” for fast-to-slow-roll transitions. Puzzling instabilities typically accompany broken supersymmetry in String Theory. However, they are absent in the former setting, and point to a mere breakdown of isotropy in the latter, which resonates with the very emergence of compact dimensions. I shall address these issues, trying to emphasize potential lessons and some key open questions.

Discussion of https://arxiv.org/pdf/2111.01139.pdf and https://arxiv.org/pdf/2111.01141.pdf. Part of new "London TQFT Journal Club" series at QMUL, please visit https://london-tqft.vercel.app to register for this and future events; some of these future meetings will be more like standard talks with speakers discussing their own work, while some will be--like this meeting--a more traditional journal club event. (Now on Zoom instead!)