Inflation on moduli space and cosmic perturbations

We show that a moduli space of the form predicted by string theory, lifted bysupersymmetry breaking, gives rise to successful inflation for large regions ofparameter space without any modification or fine tuning. This naturalrealization of inflation relies crucially on the complex nature of the modulifields and the multiple points of enhanced symmetry, which are generic featuresof moduli space but not usually considered in inflationary model building. Our scenario predicts cosmic perturbations with an almost exactly flatspectrum for a wide range of scales with running on smaller, possiblyobservable, scales. The running takes the form of either an increasingly steepdrop off of the spectrum, or a rise to a bump in the spectrum before anincreasingly steep drop off.Comment: 23 pages, 4 figures; Added Fig. 1 and re-emphasis on dynamical selection of desirable initial angles for inflaton modulus. To be published in JHE