Moduli stabilization with non-geometric fluxes -- comments on tadpole contributions and de-Sitter vacua

TL;DR

This paper investigates moduli stabilization in type IIB string theory with geometric and non-geometric fluxes, challenging existing de-Sitter solutions and clarifying flux contributions to tadpole conditions.

Contribution

It derives general properties of non-geometric flux compactifications, re-evaluates known de-Sitter solutions, and clarifies flux contributions to tadpole cancellation.

Findings

Fluxes contribute to tadpoles similarly to D-branes.

Supersymmetric Minkowski vacua are excluded in certain cases.

Known stable de-Sitter constructions are argued to be inconsistent with string theory.

Abstract

We study moduli stabilization for type IIB orientifold compactifications on Calabi-Yau three-folds with (non-)geometric fluxes. For this setting it is possible to stabilize all closed-string moduli classically without the need for non-perturbative contributions, and examples of stable de-Sitter constructions can be found in the literature which violate a prominent swampland conjecture. In this paper we derive general properties of non-geometric flux-compactifications, we argue that the contribution of fluxes to the tadpole cancellation conditions should be similar to D-branes (and not anti-D-branes), and we exclude supersymmetric Minkowski vacua for certain cases. We also reassess known stable de-Sitter constructions with (non-)geometric H-, F-, Q- and R-fluxes and argue that these are not consistent in string theory.