Related papers: Exact Dissipative Cosmologies with Stiff Fluid
We consider cosmological solutions to general relativity with a single barotropic fluid, where the pressure is a general function of the density, $p = f(\rho)$. We derive conditions for static and oscillating solutions and provide examples,…
A new class of exact solutions of Einstein's field equations with bulk viscous fluid for an LRS Bianchi type-I spacetime is obtained by using deceleration parameter as variable. The value of Hubble's constant $H_{0}$ is found to be less…
The Einstein field equation as an equation of state of a thermodynamical system of spacetime is reconsidered in the present Letter. We argue that a consistent interpretation leads us to identify scalar curvature and cosmological constant…
Considering a homogeneous and isotropic universe characterized by the Friedmann-Lema\^itre-Robertson-Walker (FLRW) line element, in this work, we have prescribed a general formalism for the cosmological solutions when the equation of state…
In this paper, we have presented bulk viscous cosmological model of the universe in the modified gravity theory in which the Lagragian of the gravitational action contains a general function $f(R, T) $, where $R$ and $T$ denote the…
Scalar-tensor gravitational theories are important extensions of standard general relativity, which can explain both the initial inflationary evolution, as well as the late accelerating expansion of the Universe. In the present paper we…
We consider plane-symmetric spacetimes satisfying Einstein's field equations with positive cosmological constant, when the matter is a fluid whose pressure is equal to its mass-energy density (i.e. a so-called stiff fluid). We study the…
We examine homogeneous but anisotropic cosmologies in scalar-tensor gravity theories, including Brans-Dicke gravity. We present a method for deriving solutions for any isotropic perfect fluid with a barotropic equation of state…
This paper explores the Friedmann field equations within the framework of Lovelock gravity, a natural extension of Einstein's gravity, focusing on both flat and open universes. Utilizing an approach based on independent Riemann tensor…
We present a novel homogeneous and geometrically flat exact solution of Einstein's General Relativity equations for an ideal fluid. The solution, which describes an expanding/contracting hypercylinder, fits well with the observational…
In the present paper, we are considering a spatially-flat Friedmann-Robertson-Walker cosmological model, fueled with stiff matter and dust, treated as non-interacting ideal fluid sources. By solving the corresponding Friedmann equation with…
We consider spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) solutions of Milgrom's recently proposed class of bimetric theories of gravity. These theories have two different regimes, corresponding to high and low…
A main issue in cosmology and astrophysics is whether the dark sector phenomenology originates from particle physics, then requiring the detection of new fundamental components, or it can be addressed by modifying General Relativity.…
The general solution of the system of General Relativity equations has been found for isotropic Universe with the flat spatial distribution and synchronized time taking into account a perfect dust and the cosmological constant.…
We present dynamical description of gravitational collapse in view of Misner and Sharp's formalism. Matter under consideration is a complicated fluid consistent with plane symmetry which we assume to undergo dissipation in the form of heat…
Considering the condition on conservation of energy momentum tensor (EMT), we study late time cosmological solutions in the context of $f(R,T)=R+\alpha T^{n}$ gravity (where $\alpha$ and $n$ are constants) in a flat FLRW spacetime. The…
We perform a global analysis of curved Friedmann-Robertson-Walker cosmologies in the presence of a viscous fluid. The fluid's bulk viscosity is governed by a first order theory recently proposed in [M. M. Disconzi, T. W. Kephart, and R. J.…
By using a solution ansatz we partially decouple the metric and the Stuckelberg sectors of the minimal massive gravity (MMGR). In this scheme for a diagonal physical metric we find the general solutions for the scalars of the theory and the…
Using the Post-Minkowskian formalism and considering rotation as a perturbation, we compute an approximate interior solution for a stationary perfect fluid with constant density and axial symmetry. A suitable change of coordinates allows…
We investigate the phase space dynamics of a bulk viscosity model in the Eckart approach for a spatially flat Friedmann-Robertson-Walker universe. We have included two barotropic fluids and a dark energy component. One of the barotropic…