SOFT INFLATION

We study the cosmology resulting from two coupled scalar fields, one which is either a new or chaotic-type inflaton and another which has an exponentially decaying potential. Such a potential may appear in the conformally transformed frame of generalized Einstein theories such as the Jordan-Brans-Dicke theory. The constraints necessary for successful inflation are examined. We find conventional grand unified theory models such as SU(5) are compatible with new inflation, while restrictions on the self-coupling constant are significantly loosened for chaotic inflation. © 1990 The American Physical Society.