Cosmological Dynamics in Interacting Scalar-Torsion f(T,$\phi$) Gravity: Investigating Energy and Momentum Couplings

TL;DR

This paper explores the cosmological behavior of a scalar field coupled to torsion gravity with matter interactions, identifying various scaling and accelerated expansion solutions relevant for dark energy modeling.

Contribution

It introduces a novel analysis of scalar-torsion gravity with energy-momentum couplings, revealing new attractor solutions including quintessence-like and de Sitter phases.

Findings

Identified scaling regimes during radiation and matter eras.

Discovered a non-accelerating scalar-dominated attractor.

Found two accelerated expansion attractors: quintessence-like and de Sitter.

Abstract

We investigate the cosmological dynamics of a homogeneous scalar field non-minimally coupled to torsion gravity, which also interacts with cold dark matter through energy and momentum transfer. The matter and radiation perfect fluids are modeled using the Sorkin-Schutz formalism. We identify scaling regimes of the field during both the radiation and matter eras. Additionally, we discovered a field-dominated scaling attractor; however, it does not exhibit accelerated expansion, making it unsuitable for describing dark energy. Nevertheless, we find two attractor solutions that do exhibit accelerated expansion: one is a quintessence-like fixed point, and the other is a de Sitter fixed point.