Power spectrum for inflation models with thermal and quantum noises

Full text: In non-isentropic inflation models, most notably in warm inflation, there is a non negligible contribution from the radiation bath to the power spectrum. In fact, in warm inflation models the dominant contribution to density perturbations come from thermal fluctuations. This is opposite to the more common cold inflation models, where the quantum fluctuations of the inflation field make the sole contribution. Little or no importance has been given to those cases where neither quantum or thermal contributions make the dominant contribution to the power spectrum. In those situations, which in fact should cover most of the parameter space of realistic quantum field theory models for inflation, it is required a complete determination of both types of contributions and also to determine under which conditions one may eventually dominate over the other. This is a most required study since, as more precise measurements of the CMB rapidly become available, greater demand is placed on more precise theoretical predictions. This requires accounting for all important effects contributing to the density perturbations. For warm inflation, it requires knowing precisely when the eventual thermalized inflation fluctuations start effectively to dominate over the quantum ones and the intermediate regimes possible. We here discuss the calculation of the total power spectrum for the inflation, leading to a result that should cover all regimes ranging from cold to warm inflation. (author)