Density perturbations in multifield inflationary models

We derive a closed-form, analytical expression for the spectrum of long-wavelength density perturbations in inflationary models with mio (or more) inflaton degrees of freedom that is valid in the slow-roll approximation. We illustrate several classes of potentials for which this expression reduces iv a simple. algebraic expression. (C) 1998 Elsevier Science B.V.