Dynamics and non-Gaussianity in the weak-dissipative warm inflation scenario

Abstract

We calculate the general solutions for a warm inflationary scenario with weak dissipation, reviewing the dissipative dynamics of the two-fluid system, and calculate the bispectrum of the gravitational field fluctuations generated in the case where dissipation of the vacuum potential during inflation is the mechanism for structure formation, but is the subdominant effect in the dynamics of the scalar field during slow-roll. The bispectrum is nonzero because of the self-interaction of the scalar field. We compare the predictions with both those of standard, or ``supercooled``, inflationary models, and warm inflation models with strong dissipation and consider the detectability of these levels of non-Gaussianity in the bispectrum of the cosmic microwave background. We find that the levels of non-Gaussianity for warm and supercooled inflation are an order of magnitude different.