Non-singular inflation with vacuum decay

TL;DR

This paper proposes a non-singular cosmological model where vacuum energy decays over time, leading to an inflationary universe that transitions smoothly to a standard cosmological evolution, matching current observational data.

Contribution

It introduces a semi-classical vacuum decay model that avoids initial singularities and aligns with observational cosmological parameters.

Findings

Universe remains non-singular during evolution.

Model matches supernova redshift-distance observations.

Late-time universe approaches de Sitter expansion.

Abstract

On the basis of a semi-classical analysis of vacuum energy in an expanding spacetime, we describe a non-singular cosmological model in which the vacuum density decays with time, with a concomitant production of matter. During an infinitely long period we have an empty, inflationary universe, with H \approx 1. This primordial era ends in a fast phase transition, during which H and \Lambda decrease to nearly zero in a few Planck times, with release of a huge amount of radiation. The late-time scenario is similar to the standard model, with the radiation phase followed by a long dust era, which tends asymptotically to a de Sitter universe, with vacuum dominating again. An analysis of the redshift-distance relation for supernovas Ia leads to cosmological parameters in agreement with other current estimations.