  We study a string theory inspired model for hybrid inflation in the context
of a brane-antibrane system partially compactified on a compact submanifold of
(a caricature of) a Calabi-Yau manifold. The interbrane distance acts as the
inflaton, whereas the end of the inflationary epoch is brought about by the
rapid rolling of the tachyon. The number of e-foldings is sufficiently large
and is controlled by the initial conditions. The slow roll parameters, however,
are essentially determined by the geometry and have little parametric
dependence. Primordial density fluctuations can be made consistent with current
data at the cost of reducing the string scale.
