Dynamical properties of scaling solutions in teleparallel dark energy cosmologies with nonminimal coupling

Abstract

The dynamical aspects of scaling solutions for the dark energy component in the theoretical framework of teleparallel gravity are considered, where dark energy is represented by a scalar field nonminimally coupled with the torsion and with a boundary term, where the boundary coupling term represents the divergence of the torsion vector. The behavior and stability of the scaling solutions are studied for scalar fields endowed with inverse power law potentials and with exponential potentials. It is shown that for scalar fields endowed with inverse power-law potentials, the stability conditions are not affected by the coupling coefficients. For the scalar fields endowed with exponential potentials, two cases are studied: at first, we have considered an infinitesimal deviation from the scaling solution in the corresponding Klein–Gordon equation, and the impact of distinct coupling coefficients on the stability of the solution are analyzed. Secondly, the potential-free case is considered where the dominance of the coupling terms over the potential term is analyzed, discussing the validity of the corresponding particular solution.

Dynamical systems applied to cosmology: Dark energy and modified gravity

“…It was found that for an exponential potential, when the coupling is positive, the cosmology evolves to a dark energy phase without requiring any fine tuning of the parameters. Marciu (2017) studied dynamical properties of scaling solutions in the later theory for both inverse power-law and exponential potentials.…”

Higgs inflation and teleparallel gravity

“…One much discussed extension of the simplest action for teleparallel gravity is the theory where the gravitational action is non-linear in T . We first consider the general case JCAP12(2019)021 f (T + 2µ ∇α T α , ϕ) [89,99,106,114,115,117,118,[185][186][187][188], where µ is a constant and ϕ is a scalar field. Let us see how the action is transformed into an action that is linear in T + 2µ ∇α T α and how our results apply.…”

Generalized tachyonic teleparallel cosmology

“…In the teleparallel setting, scalar fields have been investigated to a moderate degree, with various extensions having been investigated in the cosmological context [23][24][25][26][27][28]. Furthermore, the effects of the boundary couplings in scalar tensor theories have been discussed in various papers [25,[29][30][31][32][33][34][35][36][37][38][39][40][41]. A recent review on various studies related to dynamical analysis in different cosmological constructions can be found in [42].…”