Searching for slow-roll moduli inflation in massive type IIA supergravity with metric fluxes

By Raphael Flauger, S. Paban, D. Robbins, T. Wrase. 2008

136 citations recorded by the source corpus.

We derive several no-go theorems in the context of massive type IIA string theory compactified to four dimensions in a way that, in the absence of fluxes, preserves $\mathcal{N}=1$ supersymmetry. Our derivation is based on the dilaton, K\"ahler and complex structure moduli dependence of the potential of the four-dimensional effective field theory, that is generated by the presence of $D6$-branes, $O6$-planes, RR fluxes, NSNS 3-form flux, and geometric fluxes. To demonstrate the usefulness of our theorems, we apply them to the most commonly studied class of toroidal orientifolds. We show that for all but two of the models in this class the slow-roll parameter $ϵ$ is bounded from below by numbers of order unity as long as the fluxes satisfy the Bianchi identities, ruling out slow-roll inflation and even the existence of de Sitter extrema in these models. For the two cases that avoid the no-go theorems, we provide some details of our numerical studies, demonstrating that small $ϵ$ can indeed be achieved. We stress that there seems to be an $\ensuremath{\eta}$-problem, suggesting that none of the models in this class are viable from a cosmological point of view at least at large volume, small string coupling, and leading order in the ${\ensuremath{\alpha}}^{\ensuremath{'}}$-expansion.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4256d439425cb018ed9ba2ec0d0b1b61d8ab18f3

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Citations in the corpus

Bounds on slow roll and the de Sitter Swampland (2018, background): “, [20, 22]) in the literature that construct de Sitter solutions in explicit tree level constructions, that do seem to superficially violate the bound suggested in [7].”
Towards classical de Sitter solutions in string theory (2009, methodology): “Our investigation is guided by various no-go theorems, some appeared in the recent literature [1–5] and some we proved along the way.”
De Sitter hunting in a classical landscape (2011, methodology): “In [9] the authors investigated the existence of dS extrema in 17 abelian orbifolds of small order and found that all of their examples except Z2 × Z2 can be excluded by no-go theorems.”
The Landscape, the Swampland and the Era of Precision Cosmology (2018, background): “These models are in the class studied in [113, 114] and the consequent papers, where it is hard to avoid the situation with V,φ = 0.”
de Sitter swampland conjecture and the Higgs potential (2018, background): “The same holds for dS critical points constructed in classical type II flux compactifications [41,42].”
Inflation and String Theory (2014, background): “However, in the best-understood classes of type IIA compactifications, there are no-go theorems for inflation [501, 502] (see also [503]).”
What if string theory has no de Sitter vacua? (2018, background): “Most of the work on constructing dS critical points in this setup was carried out in IIA supergravity with O6 sources, see for instance [49, 50] for the first solutions ever constructed and [51] for a review and a large scan of solutions.”
The Swampland: Introduction and Review (2019, background): “There are some proposed counter examples, see for example [471–473,475,478], to the de Sitter conjecture, which respect the refined de Sitter conjecture, but which still do not fully address some elements listed above.”