Choice of vacuum state and the relation between inflationary and Planck scales

Abstract

Recent observations about the cosmic microwave background evidence a clear discrepancy between the scale of inflation and the Planck scale expected in the conventional inflationary picture, based on simple chaotic inflationary models. This paper explores a possible resolution of this conflict by considering a slight modification of the standard general relativity scenario, which naturally incorporates a cutoff scale consistent with the observations. This last scale of power suppression appears by the combined effect of the preinflationary background dynamics and an associated initial vacuum state for the cosmological perturbations which differs from the conventional Bunch-Davies state of slow-roll inflation. We revise and correct previous discussions in the literature about the relation between this scale and the scale corresponding to the onset of inflation. The mechanism that produces this cutoff is intimately related to the criterion determining a privileged vacuum state for the primordial perturbations. We adhere to a recent proposal based on an asymptotic diagonalization of the Hamiltonian of the perturbations and leading to a non-oscillatory primordial power spectrum. With this choice, we are able to investigate analytically the model, studying in detail some physically interesting cases. These analytic calculations provide further support to our arguments about the relation between the different scales of the system.

15 pages, 7 figures. Minor editing, final version

References in corpus (15)

• Quantum Nature of the Big Bang
• Black Hole Remnants in the Early Universe
• Quantum Gravity in the Sky: Interplay between fundamental theory and observations
• Preferred instantaneous vacuum for linear scalar fields in cosmological space-times
• The CMB Quadrupole depression produced by early fast-roll inflation: MCMC analysis of WMAP and SDSS data
• Effects of a pre-inflation radiation-dominated epoch to CMB anisotropy
• Novel quantum initial conditions for inflation
• Can effects of quantum gravity be observed in the cosmic microwave background?
• Hint of a truncated primordial spectrum from the CMB large-scale anomalies
• Quantum phenomenological gravitational dynamics: A general view from thermodynamics of spacetime
• Analytical investigation of pre-inflationary effects in the primordial power spectrum: From General Relativity to hybrid Loop Quantum Cosmology
• Large Scale Suppression of Scalar Power on a Spatial Condensation
• Missing large-angle correlations versus even-odd point-parity imbalance in the cosmic microwave background
• Angular correlations of causally-coherent primordial quantum perturbations
• Understanding large scale CMB anomalies with the generalized non-minimal derivative coupling during inflation

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