Inflationary perturbations from a potential with a step

We use a numerical code to compute the density perturbations generated during an inflationary epoch which includes a spontaneous symmetry breaking phase transition. A sharp step in the inflaton potential generates k dependent oscillations in the spectrum of primordial density perturbations. The amplitude and extent in wave number of these oscillations depends on both the magnitude and gradient of the step in the inflaton potential. We show that observations of the cosmic microwave background anisotropy place strong constraints on the step parameters.