Moduli Stabilization and Cosmology of Type IIB on SU(2)-Structure Orientifolds

TL;DR

The paper investigates type IIB flux compactifications on SU(2)-structure manifolds with O5- and O7-planes, deriving a 4D N=1 scalar potential that can stabilize all bulk moduli in a supersymmetric AdS vacuum (in at least one explicit model) while revealing no-go theorems that preclude classical de Sitter vacua or slow-roll inflation in most examples. It demonstrates a formal T-duality to type IIA with non-geometric fluxes, and provides a suite of explicit coset and twisted-torus models to test cosmological scenarios. The results show that tree-level AdS stabilization is robust in this setup, but stable dS solutions remain elusive, with one model yielding a dS point accompanied by tachyons. The work lays groundwork for further exploration of non-geometric fluxes and open-string sectors to probe potential cosmological realizations within geometric SU(2)-structure backgrounds.

Abstract

We consider type IIB flux compactifications on six-dimensional SU(2)-structure manifolds with O5- and O7-planes. These six-dimensional spaces allow not only for F_3 and H_3 fluxes but also for F_1 and F_5 fluxes. We derive the four-dimensional N=1 scalar potential for such compactifications and present one explicit example of a fully stabilized AdS vacuum with large volume and small string coupling. We then discuss cosmological aspects of these compactifications and derive several no-go theorems that forbid dS vacua and slow-roll inflation under certain conditions. We also study concrete examples of cosets and twisted tori and find that our no-go theorems forbid dS vacua and slow-roll inflation in all but one of them. For the latter we find a dS critical point with εnumerically zero. However, the point has two tachyons and eta-parameter η\approx -3.1.