Sensitivity of inflationary predictions to pre-inflationary phases

Abstract

How sensitive are the predictions of inflation to pre-inflationary conditions when the number of efolds of inflation is not too large? In an attempt to address this question, we consider a simple model where the inflationary era is preceded by an era dominated by a radiation fluid, which is coupled to the inflaton only gravitationally and which extends back to the Planck era. We show that there is a natural generalized Bunch-Davies vacuum state for perturbations to the coupled inflaton-gravity-fluid system at early times. With this choice of initial state the model predicts interesting deviations from the standard power spectrum of single field slow-roll inflation at large scales. However, the deviations are too small to be observable in near future CMB observations.

35 pages, 7 figures, submitted to JCAP

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• CMBPol Mission Concept Study: Probing Inflation with CMB Polarization
• Reheating constraints to inflationary models
• Energy Transfer in Multi Field Inflation and Cosmological Perturbations
• The pre-inflationary vacuum in the cosmic microwave background
• Effects of a pre-inflation radiation-dominated epoch to CMB anisotropy
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Cited by in corpus (7)

• Primordial backgrounds of relic gravitons
• Hemispherical Anomaly from Asymmetric Initial States
• Anisotropic non-Gaussianity from Rotational Symmetry Breaking Excited Initial States
• Inhomogeneous Initial Data and Small-Field Inflation
• A solution to the initial condition problems of inflation : NATON
• Tracking Pre-inflation Era from density perturbation spectra
• Planckian hypersurfaces, inflation and bounces