Eternal Inflation with alpha'-Corrections
Alexander Westphal
TL;DR
The paper investigates whether higher-order $oldsymbol{oldsymbol{\alpha'}}$-corrections in type IIB flux compactifications can realize inflation driven by the volume modulus $oldsymbol{T}$. By coupling a racetrack superpotential to $oldsymbol{oldsymbol{\alpha'}}$-induced no-scale breaking, it constructs a potential with three minima and two flat saddle points, enabling slow-roll inflation of the $oldsymbol{T}$-modulus and leading to a metastable de Sitter minimum with a small cosmological constant. The model achieves around $oldsymbol{130}$ e-foldings, yields a scalar spectral index $oldsymbol{n_s \approx 0.93}$ consistent with WMAP3 within the explored parameter space, and predicts an effectively negligible tensor-to-scalar ratio. Moreover, the saddle points support eternal topological inflation, alleviating initial-condition fine-tuning and yielding a robust cosmological history with viable post-inflation phenomenology on D7-branes.
Abstract
Higher-order alpha'-corrections are a generic feature of type IIB string compactifications. In KKLT-like models of moduli stabilization they provide a mechanism of breaking the no-scale structure of the volume modulus. We present a model of inflation driven by the volume modulus of flux compactifications of the type IIB superstring. Using the effects of gaugino condensation on D7-branes and perturbative alpha'-corrections the volume modulus can be stabilized in a scalar potential which simultaneously contains saddle points providing slow-roll inflation with about 130 e-foldings. We can accommodate the 3-year WMAP data with a spectral index of density fluctuations n_s=0.93. Our model allows for eternal inflation providing the initial conditions of slow-roll inflation.