Stability of the non-perturbative $O(D,D)$ de-Sitter spacetime. The isotropic case

TL;DR

This paper investigates the stability of de-Sitter solutions in string theory using $O(d,d)$ symmetry, finding that such solutions are generally unstable unless specific conditions are met, supporting the de-Sitter conjecture.

Contribution

It provides a non-perturbative analysis of de-Sitter spacetime stability in string theory with a focus on the isotropic case and generalized dilaton couplings.

Findings

De-Sitter solutions are unstable with constant generalized dilaton.

Stability requires specific dilaton couplings resembling a cosmological constant.

The analysis supports the de-Sitter conjecture in string theory.

Abstract

The existence of de-Sitter solutions and their stability within string theory became, in recent years, one of the central research questions within the string theory community. The so-called de-Sitter conjecture states that the de-Sitter vacua are unstable within string theory. Here, we study the de-Sitter solutions in string theory and their stability in the time direction using the $O(d,d)$ symmetry approach allowing for the calculation of the generic form of the string theory effective action. We study the undiscussed case of the constant generalized dilaton as well as the general form of dilaton couplings. Our findings suggest that de-Sitter solutions are unstable for the constant generalized dilaton both with and without matter. Furthermore, we found that in order for the theory to be weakly coupled the general form of dilaton coupling is in the form of a cosmological constant.