de Sitter in non-supersymmetric string theories: no-go theorems and brane-worlds

Understand

We study de Sitter configurations in ten-dimensional string models where supersymmetry is either absent or broken at the string scale.

• To this end, we derive expressions for the cosmological constant in general warped flux compactifications with localized sources, which yield no-go theorems that extend previous works on supersymmetric cases.
• We frame our results within a dimensional reduction and connect them to a number of Swampland conjectures, corroborating them further in the absence of supersymmetry.
• Furthermore, we construct a top-down string embedding of de Sitter brane-world cosmologies within unstable anti-de Sitter landscapes, providing a concrete realization of a recently revisited proposal.