On stable type IIA de-Sitter vacua with geometric flux

Abstract

We present T -dual pairs of tachyon free (stable) AdS as well as dS solutions in the context of type II orientifold compactifications. In our construction, the type IIA setting is a purely geometric flux model which, in addition, includes the usual NS-NS three-form flux H 3 and the RR p-form fluxes F p for p ∈ {0, 2, 4, 6}, while the T -dual type IIB model includes (non-)geometric fluxes along with the usual S-dual pair of the three-form (F 3 , H 3 ) fluxes. In both the models there is one combination of the RR axions which remains flat, and the dS solution is realized through the D-term effects induced by (non-)geometric fluxes, without which one can only have AdS solutions. Using flux scaling arguments we also discuss how to engineer a parametric control in these models, in the sense of realizing the respective AdS/dS solutions in large volume, weak string-coupling as well as large complex-structure regime. We also discuss open possibilities (e.g. about the unknown status on having the complete set of Bianchi identities) under which such tachyon free dS solutions may or may not be viable.

Type IIB flux compactifications with h1,1 = 0

“…Nevertheless, we discuss them for the following two reasons: firstly, they were recently studied in [20] and in the dual type IIA picture in [87] and we would like to comment on and extend these previous results. Secondly, dS vacua are notoriously difficult to construct in purely classical scalar potentials [88] and only very few explicit solutions without tachyons exist in the literature [89][90][91][92]. Therefore, it is interesting to check whether they also exist in our simple models or not.…”