Eternal Inflation in Swampy Landscapes

Understand

The much-discussed swampland conjectures suggest significant constraints on the properties of string theory landscape and on the nature of the multiverse that this landscape can support.

• The conjectures are especially constraining for models of inflation; in particular, they exclude the existence of de Sitter (dS) vacua.
• If the conjectures are false and dS vacua do exist, it still appears that their construction in string theory requires a fair amount of fine-tuning, so they may be vastly outnumbered by AdS vacua.
• Here we explore the multiverse structure suggested by these considerations.