Classical de Sitter solutions in three dimensions without tachyons?

TL;DR

This paper investigates classical de Sitter solutions in three-dimensional compactifications of massive IIA supergravity, exploring the role of anti-branes and flux quantization in stabilizing or destabilizing these vacua.

Contribution

It demonstrates that anti-brane induced supersymmetry breaking can eliminate tachyons in 3d dS solutions, but flux quantization challenges their stability in explicit models.

Findings

Anti-D2 and anti-D6 sources can remove tachyons in 3d dS vacua.

Flux quantization can eliminate the meta-stable dS window in concrete examples.

Larger tadpoles and warped throats may help but risk destabilization via brane-flux decay.

Abstract

We continue the study of compactifications of massive IIA supergravity on G2 orientifolds and demonstrate that breaking supersymmetry with anti-D2 and anti-D6 sources leads to 3d theories for which the typical tachyons haunting classical dS solutions can be absent. However for a concrete torus example the meta-stable dS window disappears after a quantization of fluxes and charges. We discuss the prospects of more general G2 compactifications and argue that they could potentially alleviate the tachyon problem by introducing larger tadpole numbers and warped throats. However, exactly those ingredients then seem to push the vacuum towards the brink of perturbative brane-flux decay in the open string sector. This is either a remarkable illustration of the no-dS swampland conjecture or such vacua live in very difficult to control regions of parameter space.