To theory of asymptotically stable accelerating Universe in Riemann-Cartan spacetime

Abstract

Homogeneous isotropic cosmological models built in the framework of the Poincaré gauge theory of gravity based on general expression of gravitational Lagrangian with indefinite parameters are analyzed. Special points of cosmological solutions for flat cosmological models at asymptotics and conditions of their stability in dependence of indefinite parameters are found. Procedure of numerical integration of the system of gravitational equations at asymptotics is considered. Numerical solution for accelerating Universe without dark energy is obtained.

Poincaré gauge theory of gravity, gravitational interaction and regular accelerating universe

“…(14)- (17) allows to build regular Big Bang model of the Universe with accelerating stage of cosmological expansion at present epoch without using the notion of dark energy by virtue of the change of gravitational interaction by certain conditions in comparison with GR (see Refs. [21][22][23][24][25][26][27]. Let us to consider the most important physical consequences obtained by investigation of HIM by using eqs.…”

“…The state with ρ m = ρ max corresponds to a bounce and near to this state the gravitational interaction has the character of repulsion. In the case of models including at initial stage of expansion also scalar fields φ, the presence of which is necessary to build inflationary models, the condition (26) determines the domain of admissible values of matter parameters (ρ m , φ,φ) limited in the space of these parameters by surface L given by equality (26). The existence of this surface provides the regularity of corresponding HIM.…”

Cosmology in Poincaré gauge gravity with a pseudoscalar torsion

“…A famous example is the Poincaré gauge theory of Gravity [30][31][32][33][34][35][36][37]. Some works have been done to develop a model of geometric dark energy in the Poincaré gauge theory framework [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. In [38][39][40][41][42][43] the effect of torsion is to introduce an extra-term into matter density and pressure which gives rise to an accelerated behavior of the universe.…”

“…The torsion model in [44][45][46][47][48] contributes an oscillating aspect to the expansion rate of the universe and displays features similar to those of only the presently observed accelerating universe. In [49][50][51][52][53][54][55][56] the Lagrangian involves too many terms and indefinite parameters, which make the field equations complicated and difficult to solve and the role of each term obscure. In order to simplify the field equations, some restrictions on indefinite parameters have to be imposed.…”

“…It has a well posed initial value problem without any ghost or tachyonic propagation. Also, the field equations are allowed to contain higher derivatives in [65], which is different from [49][50][51][52][53][54][55][56], where some restrictions on indefinite parameters are imposed in order to exclude higher order derivatives. In addition, for the first family we solve the cosmological equations corresponding to the scalar torsion function by using the dynamical system approach in ref.…”