Limits from Weak Gravity Conjecture on Dark Energy Models

TL;DR

This paper applies the weak gravity conjecture to constrain dark energy models, finding that some models are in the swampland while others are viable but tightly constrained.

Contribution

It introduces a novel use of the weak gravity conjecture to evaluate the viability of specific dark energy models in cosmology.

Findings

Chaplygin-gas-type models are in the swampland

Variable cosmological constant models are viable with tight parameter constraints

The weak gravity conjecture imposes significant restrictions on dark energy theories

Abstract

The weak gravity conjecture has been proposed as a criterion to distinguish the landscape from the swampland in string theory. As an application in cosmology of this conjecture, we use it to impose theoretical constraint on parameters of two types of dark energy models. Our analysis indicates that the Chaplygin-gas-type models realized in quintessence field are in the swampland, whereas the $a$ power-low decay model of the variable cosmological constant can be viable but the parameters are tightly constrained by the conjecture.