Towards conformal cosmology

TL;DR

This paper reviews models based on conformal symmetry as an alternative to de Sitter symmetry for explaining the nearly scale-invariant power spectrum of scalar perturbations in the early Universe, highlighting their unique features.

Contribution

It provides a concise overview of conformal symmetry-based models for cosmology and discusses their potential observable signatures, offering an alternative perspective to inflationary models.

Findings

Conformal symmetry can produce a nearly scale-invariant power spectrum.

Models based on conformal invariance offer distinct observable features.

Conformal models provide an alternative explanation to de Sitter symmetry for early Universe perturbations.

Abstract

Approximate de Sitter symmetry of inflating Universe is responsible for the approximate flatness of the power spectrum of scalar perturbations. However, this is not the only option. Another symmetry which can explain nearly scale-invariant power spectrum is conformal invariance. We give a short review of models based on conformal symmetry which lead to the scale-invariant spectrum of the scalar perturbations. We discuss also potentially observable features of these models.