Non-singular solutions in f(R, T) gravity coupled with a bulk viscous fluid
Department of Physics, Dibrugarh University, 786004, Dibrugarh, Assam, India
Accepted: 9 March 2023
Published online: 22 March 2023
In this paper, we have derived exact solutions to the Raychaudhuri equation in the presence of a bulk viscous fluid in f(R, T) modified gravity. We obtained the solutions for two distinct cases: the case of general relativity (GR) and non-GR. We have identified that these solutions can describe a non-singular inflationary Universe, i.e. the Emergent Universe (EU). It is seen that the Einstein static (ES) radius of the EU depends on the viscosity parameters and the parameter () associated with the f(R, T) model in consideration. In other words, we found that bulk viscosity plays an effective role in determining the ES radius. Further, we also looked upon the inflationary evolution for the model in terms of the temporal variation of the Equation of State (EoS) parameter of the associated inflaton field in light of the latest BICEP2-Keck-Planck (BKP) data. It is found that the model evolves within the constraints set by the BKP data. We have also investigated whether the general solutions obtained for the model can be used as a possible explanation for the present day accelerated expansion of the Universe, based on the statefinder diagnostics and luminosity distance modulus curve. We found that the solutions obtained in our model are well behaved and approach the CDM phase. Finally, we examined the late-time behaviour of the model by constraining it using the recent Union2.1 supernova dataset and Hubble data.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.