INFLATION AT LOW SCALES - GENERAL-ANALYSIS AND A DETAILED

Models Of inflationary cosmology based on spontaneous symmetry breakin g typically suffer from the shortcoming that the symmetry-breaking sca le is driven to nearly the Planck scale by observational constraints. In this paper we investigate inflationary potentials in a general cont ext, and show that this difficulty is characteristic only of potential s V(phi) dominated near their maxima by terms of order phi(2). We find that potentials dominated by terms of order phi(m) with m>2 can satis fy observational constraints at an arbitrary symmetry-breaking scale. Of particular interest, the spectral index of density fluctuations is shown to depend only on the order of the lowest nonvanishing derivativ e of V(phi) near the maximum. This result is illustrated in the contex t of a specific model, with a broken SO(3) symmetry, in which the pote ntial is generated by gauge boson loops.