Perturbative Kähler Moduli Inflation

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 Kähler 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 Kähler modulus. For the case of two Kähler moduli, we explicitly construct two classes of inflationary potentials within the Kähler 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 $V(\ddot{I}•)=V_0(1+C_1\ddot{I}{•}^{2/3})$ 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 $V(\ddot{I}•)=V_0(1+C_2\ddot{I}{•}^{-2/3})$, 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.

15 pages + Appendix. New References added and sections revised. Comments are welcomed!