2017/11/30 by Kazuharu Bamba, Davood Momeni, Mudhahir Al Ajmi
Physics and Astronomy · #Advanced Differential Geometry Research #Attractor #Black Holes and Theoretical Physics #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Dark energy #De Sitter space #De Sitter universe #Geometry #Mathematical analysis #Mathematical physics #Physics #Quantum mechanics #Scalar (mathematics) #Scalar field #Spacetime #Universe #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1140/epjc/s10052-018-6240-z
published as Eur.Phys.J. C78 (2018) no.9, 771 · 14 pages, 3 figures, title changed, version accepted for publication in European Physical Journal C
openalex publication_date 2018/09/01 · arxiv created 2018/09/12 · arxiv updated 2018/10/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We study cosmological solutions in nonlocal teleparallel gravity or f(T) theory, where T is the torsion scalar in teleparallel gravity. This is a natural extension of the usual teleparallel gravity with nonlocal terms. In this work the phase space portrait proposed to describe the dynamics of an arbitrary flat, homogeneous cosmological background with a number of matter contents, both in early- and late-time epochs. The aim was to convert the system of the equations of the motion to a first order autonomous dynamical system and to find fixed points and attractors using numerical codes. For this purpose, firstly we derive effective forms of cosmological field equations describing the whole cosmic evolution history in a homogeneous and isotropic cosmological background and construct the autonomous system of the first order dynamical equations. In addition, we investigate the local stability in the dynamical systems called “the stable/unstable manifold” by introducing a specific form of the interaction between matter, dark energy, radiation and a scalar field. Furthermore, we explore the exact solutions of the cosmological equations in the case of a de Sitter spacetime. In particular, we examine the role of an auxiliary function called “gauge” η in the formation of such cosmological solutions and show whether the de Sitter solutions can exist or not. Moreover, we study the stability issue of the de Sitter solutions both in vacuum and non-vacuum spacetimes. It is demonstrated that, for nonlocal f(T) gravity, the stable de Sitter solutions can be produced even in vacuum spacetime.