# Non-perturbative de Sitter vacua via $\alpha'$ corrections

## TL;DR

This paper demonstrates that string theory can admit de Sitter vacua through non-perturbative $oldsymbol{ ext{alpha'}}$ corrections, revealing a new potential for realizing cosmological solutions in string theory.

## Contribution

It classifies all $oldsymbol{ ext{alpha'}}$ corrections consistent with $O(d,d)$ duality for time-dependent backgrounds and shows these can produce duality-invariant de Sitter vacua non-perturbatively.

## Key findings

- Existence of duality-invariant de Sitter solutions in string theory.
- De Sitter vacua are realized non-perturbatively in $oldsymbol{ ext{alpha'}}$ corrections.
- Complete classification of $oldsymbol{ ext{alpha'}}$ corrections compatible with $O(d,d)$ invariance.

## Abstract

The higher-derivative $\alpha'$ corrections consistent with $O(d,d)$ duality invariance can be completely classified for cosmological, purely time-dependent backgrounds. This result is used to show that there are duality invariant theories featuring string-frame de Sitter vacua as solutions that are non-perturbative in $\alpha'$, thus suggesting that classical string theory may realize de Sitter solutions in an unexpected fashion.