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.
Highlights
In this work in particular we will consider 3d vacua
In [12] we have argued that compactifications of massive IIA supergravity on G2 orientifolds with fluxes can lead to full moduli stabilization in 3d (SUSY) AdS vacua that allow a tuning to arbitrary weak string coupling, large radii and a parametric separation of scales between the AdS length and the KK scale
Such striking parametric separation of scales at weak coupling is in contradiction with some Swampland conjectures [15]
Summary
We have argued in a previous paper that G2 compactifications of massive IIA supergravity with O2/O6 sources allow the stabilization of all moduli if enough fluxes are turned on [12]. We start our analysis by restricting to the universal bulk moduli, that is the dilaton and the volume These scalars are the typical place where the classical tachyonic instability would show up when we study Minkowski/de Sitter vacua with broken and full moduli stabilization.. The “Minkowski limit” is = 0 and we will consider it essentially as a crude estimation to test stability, and building on that, only a small uplifting will give metastable de Sitter Once we apply these equations to the scalar potential we get after few manipulations. We conclude that we have at hand a classical framework for “mass production” of 3d de Sitter The reason it works (at the level of the 2 universal scalars) is exactly because of our arguments surrounding Fig. 1: we have assumed small (effectively put it to zero) and found a positive mass matrix in the universal directions. Whether or not the smearing of the orientifolds is a problem depends probably on how small the coupling can be and how large the internal volume is [26]
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