Conformal Universe as false vacuum decay

TL;DR

This paper proposes that the (pseudo-)conformal Universe scenario can be modeled as a false vacuum decay process, where a metastable conformal vacuum transitions via bubble nucleation, producing perturbations similar to those in traditional models.

Contribution

It introduces a new interpretation of the conformal Universe scenario as a false vacuum decay, linking bubble nucleation to cosmological perturbations.

Findings

Perturbations around the bubble match those in homogeneously rolling models.

Spectator field perturbations have a flat power spectrum.

Late-time properties of perturbations are consistent with original models.

Abstract

We point out that the (pseudo-)conformal Universe scenario may be realized as decay of conformally invariant, metastable vacuum, which proceeds via spontaneous nucleation and subsequent growth of a bubble of a putative new phase. We study perturbations about the bubble and show that their leading late-time properties coincide with those inherent in the original models with homogeneously rolling backgrounds. In particular, the perturbations of a spectator dimension-zero field have flat power spectrum.