Semiclassical predictions regarding a pre-inflationary era and its effects on the power spectrum

Abstract

An investigation is undertaken into the properties and effects of a preinflationary era during at least part of which semiclassical gravity was valid. It is argued that if the Universe (or our part of it) was approximately homogeneous and isotropic during that era, then the Universe was likely to have been radiation dominated. A simple model in which the Universe contains classical radiation and a cosmological constant is used to investigate potential effects of such a preinflationary era on the cosmic microwave background. The power spectrum is computed using the mode functions of a quantized massless minimally coupled scalar field. Various choices of state for this field are considered, including adiabatic vacuum states of various orders and the vacuum state that would naturally occur if the Universe made a sudden transition from being radiation dominated to de Sitter space. In all cases investigated, there is a suppression of the power spectrum at large angles, and, when plotted as a function of the momentum parameter, there are always oscillations with state-dependent amplitudes.

Parts of the paper have been substantially rewritten, minor changes and corrections elsewhere, references added, Phys. Rev. D version, 34 pages, 6 figures

References in corpus (8)

• The pre-inflationary vacuum in the cosmic microwave background
• Just enough inflation: power spectrum modifications at large scales
• Preferred instantaneous vacuum for linear scalar fields in cosmological space-times
• Effects of a pre-inflation radiation-dominated epoch to CMB anisotropy
• The large scale CMB cut-off and the tensor-to-scalar ratio
• Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum
• Role of trans-Planckian modes in cosmology
• A radiation-like era before inflation

Cited by in corpus (5)

• Pre-Inflationary Bounce Effects on Primordial Gravitational Waves of $f(R)$ Gravity
• Effects of a Pre-inflationary de Sitter Bounce on the Primordial Gravitational Waves in $f(R)$ Gravity Theories
• Low Energy States and CPT invariance at the Big Bang
• Appearances are deceptive: Can graviton have a mass?
• Argument for the radiation-dominated behavior of matter fields in the preinflationary era