On Asymptotic Dark Energy in String Theory

TL;DR

This paper investigates the possibility of accelerated expansion in asymptotic regions of string theory moduli space, providing evidence supporting conjectures that restrict such expansion and exploring potential links between key conjectures.

Contribution

It offers the first explicit checks of the Strong Asymptotic dS Conjecture in non-geometric type IIB compactifications without Kähler moduli, supporting the conjecture's validity.

Findings

No violation of the Strong Asymptotic dS Conjecture was found.

A new mechanism linking the Sharpened Distance Conjecture and the Strong Asymptotic dS Conjecture is proposed.

The results support the absence of accelerated expansion in asymptotic string theory regions.

Abstract

We examine bounds on accelerated expansion in asymptotic regions of the moduli space in string theory compactifications to four spacetime dimensions. While there are conjectures that forbid or constrain accelerated expansion in such asymptotic regions, potential counter examples have been discussed recently in the literature. We check whether such counter examples can arise in explicit string theory constructions, focusing in particular on non-geometric compactifications of type IIB string theory that have no K\"ahler moduli. We find no violation of the Strong Asymptotic dS Conjecture and thus provide support for the absence of accelerated expansion in asymptotic regions of a barely explored corner of the string landscape. Moreover, working in a simplified setting, we point out a new mechanism for potentially connecting the Sharpened Distance Conjecture and the Strong Asymptotic dS Conjecture. If this argument could be generalized, it would mean that the Sharpened Distance Conjecture is implied by the Strong Asymptotic dS Conjecture, and that their exponential factors are naturally related by a factor of 2.