Density Perturbations of Thermal Origin During Inflation

Abstract

We study thermally induced density perturbations during inflation. This scenario is characterized by two thermodynamical conditions: (1) The primordial perturbations originate in the epoch when the inflationary universe contains a thermalized heat bath. (2) The perturbations of the inflationary scalar field are given by the fluctuation-dissipation relation. We show that the spectrum of the primordial perturbations is of power law, but tilted, and there is a relation between the amplitude and the index of the power spectrum. Aside from the mass scale of the inflation, the amplitude-index relation does not depend on other parameters like $g$-factor. These results are found to be well consistent with observations of the temperature fluctuations of cosmic microwave background if the mass scale of the inflation is about $10^{15}$ GeV. Instead of the purely adiabatic case, the consequent density perturbation is an admixture of adiabatic and isocurvature one. Therefore, the detection of super-Hubble suppression of the spectrum would be effective for further discrimination between the thermally originated models and others.

21 pages, 7 postscript figures, using revtex

Cited by in corpus (11)

• Perturbation Spectra in the Warm Inflationary Scenario
• Non-Gaussian Signatures in the Cosmic Background Radiation from Warm Inflation
• A numerical study of pseudoscalar inflation with an axion-gauge field coupling
• Spontaneous baryogenesis in warm inflation
• Mass Density Perturbations from Inflation with Thermal Dissipation
• Correlated Hybrid Fluctuations from Inflation with Thermal Dissipation
• Detection Limits for Super-Hubble Suppression of Causal Fluctuations
• A relativistic calculation of super-Hubble suppression of inflation with thermal dissipation
• Trans-Planckian Effects in Warm Inflation
• Time-dependent correlations of inflationary perturbations
• Electromagnetic coupling effects in natural inflation