Perturbations in non-flat cosmology for f(T) gravity
Sebastian Bahamonde (Laboratory of Theoretical Physics, Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu, 50411, Estonia, Department of Physics, Tokyo Institute of Technology, 1-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan); Konstantinos Dialektopoulos (Laboratory of Physics, Faculty of Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece, Department of Physics, Nazarbayev University, 53 Kabanbay Batyr avenue, Astana, 010000, Kazakhstan); Manuel Hohmann (Laboratory of Theoretical Physics, Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu, 50411, Estonia); Jackson Said (Department of Physics, University of Malta, Msida, Malta, Institute of Space Sciences and Astronomy, University of Malta, Msida, Malta); Christian Pfeifer (ZARM, University of Bremen, Bremen, 28359, Germany); et al - Show all 6 authors
The study of cosmological perturbation theory in f(T) gravity is a topic of great interest in teleparallel gravity since this is one of the simplest generalizations of the theory that modifies the teleparallel equivalent of general relativity. In this work, we explore the possibility of a non-flat FLRW background solution and perform perturbations for positively as well as negatively curved spatial geometries, together with a comparison to the flat case. We determine the generalized behaviour of the perturbative modes for this non-flat FLRW setting for arbitrary f(T) models, when the most general homogeneous and isotropic background tetrads are used. We also identify propagating modes in this setup, and relate this with the case of a flat cosmology.
