Accidental inflation in string theory

We show that inflation in type IIB string theory driven by the volume modulus can be realized in the context of the racetrack-based Kallosh-Linde model (KL) of moduli stabilization. Inflation here arises through the volume modulus slow-rolling down from a. at hilltop or inflection point of the scalar potential. This situation can be quite generic in the landscape, where by uplifting one of the two adjacent minima one can turn the barrier either into a. at saddle point or into an inflection point supporting eternal inflation. The resulting spectral index is tunable in the range of 0.93 less than or similar to n(s) less than or similar to 1, and there is only negligible production of primordial gravitational waves r < 10(-6). The flatness of the potential in this scenario requires fine-tuning, which may be justified taking into account the exponential reward by volume factors preferring the regions of the universe with the maximal amount of slow-roll inflation. This consideration leads to a tentative prediction of the spectral index ns approximate to 0.95 or 0.93, depending on whether the potential has a symmetry phi -> -phi or not.