Narrow Results

In this paper, we have presented the cosmological model in Brans–Dicke theory (BDT) of gravity for a Bianchi type-IX spacetime. We obtained the exact solutions of the field equations by applying the new form of deceleration parameter, i.e. fractional linear varying deceleration parameter (FLVDP) as proposed by R. K. Mishra and A. Chand [Astrophys. Space Sci. 361, 1 (2016)]. In this paper, we have also presented the physical and geometric properties and mathematical analysis of the proposed model. Then we have provided the energy conditions and statefinder diagnostic.

Modern cosmology establishes the scenario of accelerated expansion of the universe and the reason for this is supposed to be the exotic negative pressure named dark energy. In light of this, investigation of dark energy models to explain the above scenario assumes paramount importance. Here we obtain dark energy models in the presence of massive scalar meson fields in the Lyra manifold [Math. Z. 54, 52 (1951)] corresponding to Bianchi type-IX space–time. We obtain deterministic models solving field equations using some relevant physical conditions. Dynamical properties of the model are presented and their relevance to the modern observational cosmology is discussed.

A self-gravitating Skyrmion is an analytic and globally regular solution of the Einstein–Skyrme system with nonvanishing topological charge. The spacetime is the direct product $R\times S^3$ and the Skyrmion is the self-gravitating generalization of the static hedgehog solution of Manton and Ruback. This solution can be promoted to a dynamical one in which the spacetime is a cosmology of the Bianchi type-IX and, through an analytic continuation, it can also be turned into a transversable asymptotically AdS Lorentzian wormhole. The stress–energy of this wormhole satisfies physically realistic energy conditions and the only “exotic matter” required by it is a negative cosmological constant.