Inflationary Constraints on Type IIA String Theory

Abstract

We prove that inflation is forbidden in the most well understood class of semi-realistic type IIA string compactifications: Calabi-Yau compactifications with only standard NS-NS 3-form flux, R-R fluxes, D6-branes and O6-planes at large volume and small string coupling. With these ingredients, the first slow-roll parameter satisfies epsilon >= 27/13 whenever V > 0, ruling out both inflation (including brane/anti-brane inflation) and de Sitter vacua in this limit. Our proof is based on the dependence of the 4-dimensional potential on the volume and dilaton moduli in the presence of fluxes and branes. We also describe broader classes of IIA models which may include cosmologies with inflation and/or de Sitter vacua. The inclusion of extra ingredients, such as NS 5-branes and geometric or non-geometric NS-NS fluxes, evades the assumptions used in deriving the no-go theorem. We focus on NS 5-branes and outline how such ingredients may prove fruitful for cosmology, but we do not provide an explicit model. We contrast the results of our IIA analysis with the rather different situation in IIB.

22 pages, 1 figure; v3: Updated to match version published in JHEP, references added

References in corpus (4)

• Roulette Inflation with Kähler Moduli and their Axions
• Lectures on Nongeometric Flux Compactifications
• Toroidal Orientifolds in IIA with General NS-NS Fluxes
• Searching for Inflation in Simple String Theory Models: An Astrophysical Perspective

Cited by in corpus (10)

• Monodromy in the CMB: Gravity Waves and String Inflation
• The effective theory of type IIA AdS4 compactifications on nilmanifolds and cosets
• On Slow-roll Moduli Inflation in Massive IIA Supergravity with Metric Fluxes
• On the Cosmology of Type IIA Compactifications on SU(3)-structure Manifolds
• Minimal Simple de Sitter Solutions
• Simple Bounds from the Perturbative Regime of Inflation
• New string vacua from twistor spaces
• An obstacle to populating the string theory landscape
• A Phase Transition between Small and Large Field Models of Inflation
• Topology from Cosmology