Emergent universe revisited through the CSL theory

Gabriel R Bengochea,Gabriel León,María Pía Piccirilli

doi:10.1140/epjc/s10052-021-09842-x

Abstract

In this work we analyze how the spectrum of primordial scalar perturbations is modified, within the emergent universe scenario, when a particular version of the Continuous Spontaneous Localization (CSL) model is incorporated as the generating mechanism of initial perturbations, providing also an explanation to the quantum-to-classical transition of such perturbations. On the other hand, a phase of super-inflation, prior to slow-roll inflation, is a characteristic feature of the emergent universe hypothesis. In recent works, it was shown that the super-inflation phase could generically induce a suppression of the temperature anisotropies of the CMB at large angular scales. We study here under what conditions the CSL maintains or modifies these characteristics of the emergent universe and their compatibility with the CMB observations.

Highlights

We will approach the emergent universe from the perspective of the Continuous Spontaneous Localization (CSL) model [216,218], which will be incorporated into the situation at hand as a mechanism to break the original symmetries of the quantum vacuum state of the field driving the expansion of the early universe, and generating the primordial cosmological perturbations
We shall proceed to examine the observational effects of implementing the CSL model in the emergent universe (EU) scenario
A very similar parameterization was implemented in a recent work involving the CSL proposal during inflation [245]

Summary

Introduction

The success of the standard ΛCDM cosmological model in explaining the many accurate astronomical observations we have today (e.g. [1,2,3,4,5]) includes inflation, a phase of accelerated expansion during the very early epoch of the universe [6,7,8,9,10,11,12,13,14,15,16,17]. We will approach the emergent universe from the perspective of the Continuous Spontaneous Localization (CSL) model [216,218], which will be incorporated into the situation at hand as a mechanism to break the original symmetries of the quantum vacuum state of the field driving the expansion of the early universe, and generating the primordial cosmological perturbations. In this manner, the CSL model naturally provides an explanation of the quantum-to-classical transition of such perturbations.

Emergent universe in the CSL framework

Power spectrum

Results

Further parameter space exploration

Conclusions