Anisotropic power-law inflation for a generalized model of two scalar and two vector fields

Abstract

Cosmological implication of a generalized model of two scalar and two vector fields, in which both scalar fields are non-minimally coupled to each vector field, is studied in this paper. In particular, we will seek a set of new anisotropic power-law inflationary solutions to this model. Additionally, the stability of the obtained solutions will be examined by using the dynamical system approach. As a result, we will show that this set of solutions turns out to be stable and attractive during the inflationary phase as expected due to the existence of the unusual couplings between two scalar and two vector fields. Notably, we will point out that the existence of phantom field will lead to an instability of the corresponding anisotropic power-law inflation.

Kinematic parameters and Raychaudhuri equation in the Kantowski-Sachs model

“…If from the observational point of view we might expect better and more accurate results before we can say with certainty that we live in a homogeneous and isotropic universe, from the theoretical analysis there are several models that treat the Universe as inhomogeneous and anisotropic. Moreover, if today the Universe can be considered homogeneous and isotropic, it was possibly inhomogeneous and anisotropic in its early days [30], undergoing an isotropic process probably due to the effects of cosmic inflation.…”