Cosmological dynamics of dark energy in scalar-torsion $f(T,phi)$ gravity. (arXiv:2011.08377v4 [gr-qc] UPDATED)

Cosmological dynamics of dark energy in scalar-torsion $f(T,phi)$ gravity. (arXiv:2011.08377v4 [gr-qc] UPDATED)
<a href="http://arxiv.org/find/gr-qc/1/au:+Gonzalez_Espinoza_M/0/1/0/all/0/1">Manuel Gonzalez-Espinoza</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Otalora_G/0/1/0/all/0/1">Giovanni Otalora</a>

It is investigated the cosmological dynamics of scalar-torsion $f(T,phi)$
gravity as a dark energy model, where $T$ is the torsion scalar of teleparallel
gravity and $phi$ is a canonical scalar field. In this context, we are
concerned with the phenomenology of the class of models with non-linear
coupling to gravity and exponential potential. We obtain the critical points of
the autonomous system, along with the stability conditions of each one of them
and their cosmological properties. Particularly, we show the existence of new
attractors with accelerated expansion, as well as, new scaling solutions in
which the energy density of dark energy scales as the background fluid density,
thus, defining the so-called scaling radiation and scaling matter epochs. The
scaling solutions are saddle points, and therefore, the system exits these
solutions to the current epoch of cosmic acceleration, towards an attractor
point describing the dark energy-dominated era.

It is investigated the cosmological dynamics of scalar-torsion $f(T,phi)$
gravity as a dark energy model, where $T$ is the torsion scalar of teleparallel
gravity and $phi$ is a canonical scalar field. In this context, we are
concerned with the phenomenology of the class of models with non-linear
coupling to gravity and exponential potential. We obtain the critical points of
the autonomous system, along with the stability conditions of each one of them
and their cosmological properties. Particularly, we show the existence of new
attractors with accelerated expansion, as well as, new scaling solutions in
which the energy density of dark energy scales as the background fluid density,
thus, defining the so-called scaling radiation and scaling matter epochs. The
scaling solutions are saddle points, and therefore, the system exits these
solutions to the current epoch of cosmic acceleration, towards an attractor
point describing the dark energy-dominated era.

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