Existence of positive-energy (de Sitter) vacua in string theory (swampland conjecture)

Establish whether string theory admits vacuum states with positive vacuum energy density (de Sitter vacua), thereby confirming or refuting the swampland conjecture that the absence of such vacua is a feature of string theory.

Background

In motivating alternatives to a cosmological constant, the paper references developments in string theory that challenge the construction of de Sitter vacua. This difficulty has motivated the swampland conjecture, which posits that such positive-energy vacua may be absent in consistent theories of quantum gravity.

The resolution of this conjecture bears directly on whether dark energy can be a true cosmological constant or must be dynamical, making it relevant to the broader context of the paper’s discussion of dark energy parametrizations.