Effects of viscous content on the modified cosmological F(T) model

Department of Physics, Faculty of Basic Sciences, University of Neyshabur - P.O. Box 9319774446, Neyshabur, Iran and Research Institute for Astronomy and Astrophysics of Maragha (RIAAM) - P.O. Box 55134-441, Maragha, Iran

^(a) sd-sadatian@um.ac.ir

Received: 10 March 2019
Accepted: 15 May 2019

Abstract

In the present study, it was assumed that according to the type of considered matter as the content of universe, the physical properties of this matter should be carefully examined in the study of the cosmological model. Viscosity is a feature of the universe matter content as discussed in the present research. Therefore, the present research sought to examine the impact of this parameter on dynamics of the universe. Accordingly, it examined the effective pressure and effective equation of state of the system by taking into account the impact of viscosity coefficients through choosing a modified F(T) gravity model (where the torsion scalar was used in the action of the model instead of the Ricci scalar). We assumed the universe with dominant dust and torsion content, and finally, modified Friedmann equations including the viscosity effects which were obtained. In this regard, with a viscous F(T) gravity, we considered the universe at low/high redshifts z.