Gravitational stability of inflatons and torsion in Einstein-Cartan-Klein-Gordon Cosmology

TL;DR

This paper investigates the gravitational stability of torsion and inflaton fields in a scalar-tensor cosmology with propagating Cartan torsion, identifying conditions for stability consistent with observations.

Contribution

It derives evolution equations for inflaton and torsion in Einstein-Cartan-Klein-Gordon cosmology and analyzes their stability modes, highlighting the astrophysical relevance.

Findings

Stable torsion mode aligns with cosmic background observations

Unstable modes are identified for certain parameter regimes

The model explains the absence of torsion relics in the universe

Abstract

Gravitational stability of torsion and inflaton potential in a four-dimensional spacetime de Sitter solution in scalar-tensor cosmology where Cartan torsion propagates is investigated in detail. Inflaton and torsion evolution equations are derived by making use of a Lagrangean method. Stable and unstable modes for torsion and inflatons are found. Present astrophysical observations favour a stable mode for torsion since this would explain why no relic torsion imprint has been found on the Cosmic Background Radiation in the universe.