Understand
We show that double inflation is naturally realized in K\"ahler moduli inflation, which is caused by moduli associated with string compactification.
- We find that there is a small coupling between the two inflatons which leads to amplification of perturbations through parametric resonance in the intermediate stage of double inflation.
- This results in the appearance of a peak in the power spectrum of the primordial curvature perturbation.
- We numerically calculate the power spectrum and show that the power spectrum can have a peak on observationally interesing scales.
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