Soft Inflation: A Model for Easing Constraints
The cosmology resulting from two coupled scalar fields, one which is either a new or chaotic type inflaton and the other which has an exponentially decaying potential, is studied. Such a potential arises in superstring theories and in the conformally transformed frame of generalized Einstein theories like the Jordan-Brans-Dicke theory. The constraints necessary for successful inflation are examined. Conventional GUT models such as SU(5) are compatible with new inflation, while restrictions on the self-coupling constant are significantly loosened for chaotic inflation when the exponential potential is fundamental, but no significant improvement for the latter occurs when in the conformal frame.