Correlated Hybrid Fluctuations from Inflation with Thermal Dissipation

Abstract

We investigate the primordial scalar perturbations in the thermal dissipative inflation where the radiation component (thermal bath) 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 calculate the fractional power ratio ($S$) and the correlation coefficient ($\cos \Delta$) between the adiabatic and the isocurvature perturbations at the commencing of the radiation regime. Since the adiabatic/isocurvature decomposition of hybrid perturbations generally is gauge-dependent at super-horizon scales when there is substantial energy exchange between the inflaton and the thermal bath, we carefully perform a proper decomposition of the perturbations. 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 inflaton. We also show that both $S$ and $\cos \Delta$ depend mainly on the ratio between the dissipation coefficient $\Gamma$ and the Hubble parameter $H$ during inflation. The correlation is positive ($\cos \Delta >0$) for strong dissipation cases where $\Gamma /H>0.2$, and is negative for weak dissipation instances where $\Gamma /H<0.2$. Moreover, $S$ and $\cos \Delta$ in this model are not independent of each other. The predicted relation between $S$ and $\cos \Delta$ is consistent with the WMAP observation. Other testable predictions are also discussed.

arXiv comment18 pages using revtex4, accepted for publication in PRD

References in corpus (21)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• 4-Year COBE DMR Cosmic Microwave Background Observations: Maps and Basic Results
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Inflation
• Warm Inflation
• Thermally Induced Density Perturbations in the Inflation Era
• Warm Inflation in the Adiabatic Regime- a Model, an Existence Proof for Inflationary Dynamics in Quantum Field Theory
• Reconstructing the primordial power spectrum
• Correlated adiabatic and isocurvature perturbations from double inflation
• An Observational Test of Two-field Inflation
• Perturbation Spectra in the Warm Inflationary Scenario
• Isocurvature Perturbations in Multiple Inflationary Models
• Adiabatic and Isocurvature Perturbations for Multifield Generalized Einstein Models
• Is Warm Inflation Possible?
• Correlated perturbations from inflation and the cosmic microwave background
• Bounds on isocurvature perturbations from CMB and LSS data
• Correlated adiabatic and isocurvature CMB fluctuations in the wake of the WMAP
• An Infrared Cutoff Revealed by the Two Years of COBE-DMR Observations of Cosmic Temperature Fluctuations
• An Attempt to Determine the Largest Scale of Primordial Density Perturbations in the Universe
• Mass Density Perturbations from Inflation with Thermal Dissipation
• Density Perturbations of Thermal Origin During Inflation
• A relativistic calculation of super-Hubble suppression of inflation with thermal dissipation

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