Emergent universe: tensor perturbations within the CSL framework

TL;DR

This paper investigates how the CSL model influences tensor perturbations in the emergent universe scenario, analyzing impacts on the B-mode polarization spectrum and potential observational signatures distinguishing it from standard cosmology.

Contribution

It introduces a novel application of the CSL model to tensor perturbations in the emergent universe, linking quantum collapse mechanisms to observable CMB polarization features.

Findings

Confirmed detection of standard-like B-modes would challenge the emergent universe.

Detection of suppressed low multipoles in B-modes supports the emergent scenario.

An upper bound on the CSL collapse parameter was established.

Abstract

We calculate the primordial power spectrum of tensor perturbations, within the emergent universe scenario, incorporating a version of the Continuous Spontaneous Localization (CSL) model as a mechanism capable of: breaking the initial symmetries of the system, generating the perturbations, and also achieving the quantum-to-classical transition of such perturbations. We analyze how the CSL model modifies the characteristics of the B-mode CMB polarization power spectrum, and we explore their differences with current predictions from the standard concordance cosmological model. We have found that, regardless of the CSL mechanism, a confirmed detection of primordial B-modes that fits to a high degree of precision the shape of the spectrum predicted from the concordance $\Lambda$CDM model, would rule out one of the distinguishing features of the emergent universe. Namely, achieving a best fit to the data consistent with the suppression observed in the low multipoles of the angular power spectrum of the temperature anisotropy of the CMB. On the contrary, a confirmed detection that accurately exhibits a suppression of the low multipoles in the B-modes, would be a new feature that could be considered as a favorable evidence for the emergent scenario. In addition, we have been able to establish an upper bound on the collapse parameter of the specific CSL model used.