Correlated perturbations from thermal dissipative inflation

We study the primordial scalar perturbations in the thermal dissipative inflation where the thermal radiation persists and the density fluctuations are thermally originated. The perturbation generated in this model is hybrid, i.e., it consists of both adiabatic and isocurvature components. We find that the adiabatic and the isocurvature perturbations are correlated, even though the fluctuations of the radiation component is considered uncorrelated with that of the inftaton. Furthermore, the correlation depends mainly on the ratio between the dissipation coefficient γ and the Hubble parameter H during inflation and the predicted relation is consistent with the WMAP observation.