Accidental Inflation in String Theory

Abstract

We show that inflation in type IIB string theory driven by the volume modulus can be realized in the context of the racetrack-based Kallosh-Linde model (KL) of moduli stabilization. Inflation here arises through the volume modulus slow-rolling down from a flat hill-top or inflection point of the scalar potential. This situation can be quite generic in the landscape, where by uplifting one of the two adjacent minima one can turn the barrier either to a flat saddle point or to an inflection point supporting eternal inflation. The resulting spectral index is tunable in the range of 0.93 < n_s < 1, and there is only negligible production of primordial gravitational waves r < 10^{-6}. The flatness of the potential in this scenario requires fine-tuning, which may be justified taking into account the exponential reward by volume factors preferring the regions of the universe with the maximal amount of slow-roll inflation. This consideration leads to a tentative prediction of the spectral index $n_s\approx 0.95$ or $n_s\approx 0.93$ depending on whether the potential has a symmetry phi -> - phi or not.

15 pages, 6 figures, LaTeX, uses RevTex 4

References in corpus (4)

• A Delicate Universe
• Eternal Inflation with alpha'-Corrections
• Moduli Stabilization in Meta-Stable Heterotic Supergravity Vacua
• Back-door fine-tuning in supersymmetric low scale inflation

Cited by in corpus (11)

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• Volume Modulus Inflation and the Gravitino Mass Problem
• Surviving the crash: assessing the aftermath of cosmic bubble collisions
• Update of D3/D7-Brane Inflation on K3 x T^2/Z_2
• Volume modulus inflection point inflation and the gravitino mass problem
• Field dynamics and tunneling in a flux landscape
• Brane Inflation is Attractive
• Inflation on an Open Racetrack
• Fine-tuning criteria for inflation and the search for primordial gravitational waves
• A Phase Transition between Small and Large Field Models of Inflation
• Intermediate Scale Inflation and Metastable Supersymmetry Breaking