Does string theory admit long-lived accelerated expansion?

Determine whether string theory can harbor long-lived accelerated expansion, such as metastable de Sitter vacua, within fully consistent and controllable constructions.

Background

The paper studies de Sitter no-go theorems for flux compactifications on Riemann-flat manifolds with Casimir energy and shows that de Sitter minima in four dimensions are excluded in this setup, while three-dimensional de Sitter minima are not ruled out. This contributes to the broader debate on whether string theory permits sustained accelerated expansion, a question linked to swampland conjectures and the scarcity of explicit de Sitter constructions.

By framing the search for de Sitter minima as a semidefinite optimization problem, the authors propose a method to systematically test candidate compactifications, but they emphasize that the overarching question of the existence of long-lived accelerated expansion in string theory remains unresolved.