Curvature bounce in general relativity: background and primordial spectrum

TL;DR

This paper explores a positively curved universe with an inflationary stage leading to a curvature bounce instead of a Big Bang, analyzing background evolution and primordial spectra with potential observational signatures.

Contribution

It introduces a model of a positively curved universe with a curvature bounce, analyzing background evolution and primordial spectra, and discusses observational implications and naturalness.

Findings

Curvature bounce replaces Big Bang in certain models.

Primordial tensor spectrum calculated with potential observational signatures.

Analysis of naturalness in curvature bounce scenarios.

Abstract

Recent data suggest that the Universe could be positively curved. Combined with an inflationary stage, this might lead to a curvature bounce instead of the Big Bang. The background evolution is presented, as a function of the parameters controlling the cosmic evolution. The primordial tensor spectrum is also calculated and possible observational footprints of the model are underlined. Several potentials are considered and general remarks are made about "naturalness" in this context.