Pre-slow roll initial conditions: large scale power suppression and infrared aspects during inflation

TL;DR

This paper investigates how pre-slow roll initial conditions during inflation can explain large-scale power suppression in the cosmic microwave background, affecting scalar perturbations, decay processes, and quantum entanglement.

Contribution

It introduces a model of initial conditions from a pre-slow roll phase that modifies the inflationary power spectrum and infrared properties of scalar fields, providing analytical insights.

Findings

Large scale power suppression correlates with initial conditions from a fast-roll stage.

Modified initial conditions affect decay widths and entanglement entropy during inflation.

Suppression of large-scale power leads to reduced dynamical masses and anomalous dimensions.

Abstract

If the large scale anomalies in the temperature power spectrum of the cosmic microwave background are of primordial origin, they may herald modifications to the slow roll inflationary paradigm on the largest scales. We study the possibility that the origin of the large scale power suppression is a modification of initial conditions during slow roll as a result of a pre-slow roll phase during which the inflaton evolves rapidly. This stage is manifest in a potential in the equations for the Gaussian fluctuations during slow roll and modify the power spectra of scalar perturbations via an initial condition transfer function $\mathcal{T}(k)$. We provide a general analytical study of its large and small scale properties and analyze the impact of these initial conditions on the infrared aspects of typical test scalar fields. The infrared behavior of massless minimally coupled test scalar field theories leads to the dynamical generation of mass and anomalous dimensions, both depend non-analytically on $\mathcal{T}(0)$. During inflation all quanta decay into many quanta even of the same field because of the lack of kinematic thresholds. The decay leads to a quantum entangled state of sub and superhorizon quanta with correlations across the horizon. We find the modifications of the decay width and the entanglement entropy from the initial conditions. In all cases, initial conditions from a ``fast-roll'' stage that lead to a suppression in the scalar power spectrum at large scales also result in a suppression of the dynamically generated masses, anomalous dimensions and decay widths.