Perturbative K\"ahler Moduli Inflation

TL;DR

This paper develops two classes of inflationary models within type IIB string theory using perturbative corrections to stabilize multiple K"ahler moduli, producing potentials consistent with cosmological observations and differing from previous models in stabilization methods and tensor-to-scalar ratios.

Contribution

The work introduces novel inflationary potentials derived from perturbative stabilization of multiple K"ahler moduli, expanding the landscape of string-inspired inflation models.

Findings

Both models fit CMB data with low tensor-to-scalar ratios.

Explicit construction of inflationary potentials within the K"ahler cone.

Different stabilization mechanisms lead to distinct tensor-to-scalar ratios.

Abstract

In this work, we present two classes of inflationary models in the framework of type IIB string theory. The inflatons correspond to blow-up K\"ahler modulus arising from compactifying type IIB string theory on a Calabi-Yau. Using perturbative corrections, we first highlight a procedure for stabilising more than one K\"ahler modulus. For the case of two K\"ahler moduli, we explicitly construct two classes of inflationary potentials within the K\"ahler cone which satisfy both EFT and cosmological constraints. The first class of models, arising from moduli redefinition of the blow-up mode, garners a potential of the form $V(\phi)=V_{0}(1+C_{1} \phi^{2/3})$ align with CMB data with scalar-to-tensor ratio $r\lesssim 10^{-2}$. The second class of models, which have been recently proposed as loop blow-up inflation, have a form $V(\phi)=V_{0}(1+C_{2}\phi^{-2/3})$, also agrees with CMB data with scalar-to tensor-ratio $r\lesssim 10^{-8}$. Our work differs from the original loop blow-up inflation in terms of stabilization mechanism and subsequently the scalar-to tensor ratio.