Stiff Matter Research Articles

New stiff matter solutions to Einstein equations

New exact solutions are presented to the Einstein field equations which are spherically symmetric and static, with a perfect fluid distribution of matter satisfying the equation of stateρ=p. One of the obtained solutions may only be used locally, the other represents the stellar interior globally and is singularity-free.

Bianchi type I cosmological model with bulk viscosity

We present some solutions of Bianchi type I cosmological models with bulk viscosity. Exact solutions are given when the universe is filled with stiff matter while the viscosity coefficients are constant or proportional to the energy density. Effects of the bulk viscosity are found to smooth out the anisotropy of the universe and create matter by the gravitational field in the course of evolution. At the final stage, cosmologies are driven to the infinite expansion state, the de Sitter spacetime, or the isotropic Friedmann universe.

Non-singular Bianchi-Kantowski-Sachs perfect fluid solutions of no-scale supergravity

We investigate the perfect fluid field equations of the Bianchi-Kantowski-Sachs models on the basis ofN=1 no-scale supergravity. A wide class of non-singular solutions is given in the stiff matter as well as in the radiation-dominated case. The vacuum solutions are included as special cases. The solutions given are of much interest in connection with the low-energy approximation of superstrings.

Anisotropic fluid with SU(2)-type structure in general relativity: A model of localized matter

A model of anisotropic fluid with three perfect fluid components in interaction is studied. Each fluid component obeys the stiff matter equation of state and is irrotational. The interaction is chosen to reproduce an integrable system of equations similar to the one associated to self-dual SU(2) gauge fields. An extension of the Belinsky–Zakharov version of the inverse scattering transform is presented and used to find soliton solutions to the coupled Einstein equations. A particular class of solutions that can be interpreted as lumps of matter propagating in empty space-time is examined.

On a generalized soliton solution as an inhomogeneous cosmological model

We consider a generalized vacuum soliton solution of Einstein's equations with three parameters. Depending on the values of the parameters it is the matching of the Kasner metric with a Wainwright, Ince and Marshman solution, the inhomogeneous version of some Bianchi III stiff matter metrics, and inhomogeneous (and homogeneous) space-times with the cosmological singularity only.

Freidmann cosmology with a cosmological 'constant' in the scale covariant theory

Homogeneous isotropic cosmologies in the presence of a cosmological 'constant' are studied in the scale covariant theory. A class of solutions is obtained for k=0 for models filled with dust, radiation or stiff matter. For k not=0, solutions are presented for the radiation models.

Finite perturbations on Friedmann-Robertson-Walker models

view Abstract Citations (23) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Finite Perturbations on Friedmann-Robertson-Walker Models Ibanez, J. ; Verdaguer, E. Abstract By dimensional reduction of solutions of Einstein's equations in five-dimensional vacuum, two metrics are derived which can be interpreted as finite cylindrical perturbations of the solitonic type on a radiative Friedmann-Robertson-Walker (FRW) cosmological background. A linear perturbative analysis is performed and is compared with the exact nonlinear results. The metrics are transformed to perfect fluid solutions representing finite soliton perturbations on a FRW background with stiff matter. One metric contains density modes, and the other includes the coupling between density and radiative modes. Publication: The Astrophysical Journal Pub Date: July 1986 DOI: 10.1086/164353 Bibcode: 1986ApJ...306..401I Keywords: Astronomical Models; Cosmology; Perturbation Theory; Relativity; Approximation; Density Distribution; Eigenvalues; Space-Time Functions; Temporal Distribution; Astrophysics; COSMOLOGY; RELATIVITY full text sources ADS |

Comment on stiff matter solutions in cosmological models based on Lyra's manifold

It is pointed out that the anisotropic cosmological model in Lyra's manifold given recently by Reddy and Innaiah (1985) is, apart from a minor difference in energy density and pressure, identical to the stiff matter anisotropic model of general relativity without a cosmological constant. Some comments are made on stiff matter solutions based on Lyra's manifold.

Higher-dimensional Bianchi cosmologies

We present new higher-dimensional Bianchi cosmologies of class A. Our solutions given are of type M n = R × M 3 × T D where N = M 3 are of types I, II, VI 0, VII 0, VIII and IX. This spectrum of solutions includes the higher-dimensional versions of the Kasner solution and the mixmaster universe with stiff matter content.

Friedmann-Robertson-Walker stiff matter solutions in the scale covariant theory

We derive Friedmann-Robertson-Walker stiff matter solutions in the scale covariant theory and discuss some properties of the solutions.

Some exact inhomogeneous solutions of Einstein’s equations with symmetries on the hypersurfaces t=const

The solution of Einstein’s field equations is studied for a metric written in the form (δ≠γ)ds2=−α2(t,r,θ,φ)dt2 +e2β(t,r) dr2+e2γ(t,r) dθ2 +e2δ(t,r)M2(θ)dφ2. A perfect fluid, which flows orthogonally to the hypersurfaces t=const is considered as matter content. These hypersurfaces admit a translational Killing vector, which will not be, in general, a Killing vector of the whole space-time. All the possible solutions are obtained when α depends on the variable φ. These solutions represent either a perfect fluid without expansion or vacuum with a cosmological constant Λ0. Some particular inhomogeneous solutions are obtained for α independently of φ. These solutions are physical, the fluid obeys an equation of state p=ρ (stiff matter), and the space-time admits, apparently, only a group G2 of isometries. A vacuum family is also obtained in this case.

A Bianchi Type V Universe with Stiff Fluid and Electromagnetic Radiation

This paper discusses the possibility of a Bianchi type V universe containing stiff matter and a source-free electromagnetic field which is, of necessity, found to be null. Physical and kinematical consequences of the model have also been considered.

Comment on the BDT-Bianchi type-VI0 stiff matter solution

We wish to point out that the Brans-Dicke-Bianchi type-VI0 stiff matter solution recently given by Ram and Singh is not the most general solution of the corresponding field equations. Moreover, this solution has no vacuum limit and the general relativistic limit is obtained only after making an asymptotic expansion. In this paper we rediscuss the entire problem in a different way. In the limit ϕ=const., ω→∞, we obtain both the stiff matter and the vacuum relativistic limit first given by Ellis and MacCallum (1969) in analytic form.

A tilted Bianchi type-V perfect fluid solution for stiff matter

We present a solution to the Einstein field equations for a massless scalar field in a Bianchi type-V spacetime, which can be interpreted as a solution for a perfect fluid with the equation of state of stiff matter. This solution complements a solution previously given by us for an anisotropic fluid.

Comment on the GRT-LRS Bianchi type-V solutions

We wish to point out that the locally rotationally symmetric (LRS) Bianchi type-V electromagnetic solutions recently given by Roy and Singh (1983) on the basis of the general theory of relativity (GRT) are wrong. The correct electromagnetic solutions are nothing but the vacuum and stiff matter solutions first given by Ftaclas (1978), which have been generalized by Jantzen (1980) and independently by Lorenz (1981).

Exact Brans-Dicke-Bianchi type-V solutions

AbstractSpatially homogeneous cosmological models of the Bianchi type-V are considered in the Brans-Dicke scalar-tensor theory of gravitation. Exact solutions are given in the vacuum case as well as for models filled with dust, radiation or stiff matter.

Exact Bianchi type VI0 cosmological solutions with matter in Brans-Dicke theory

We present an exact solution of the Brans-Dicke equations for cosmological models of Bianchi type VI0 with stiff matter. The solution represents anisotropic universe which has its analogy in Einstein's theory. The corresponding result for a plane symmetry Bianchi type I model is obtained as a special case.

Exact perfect fluid solutions in the Brans-Dicke-theory

We present the general stiff matter and radiation solutions for thek=0, 1, −1 Friedmann-Robertson-Walker space-times in the Brans-Dicke scalar-tensor theory.

Exact Brans-Dicke-Bianchi type-VIIh solutions

We discuss the Brans-Dicke-Bianchi type-VIIh field equations. Exact solutions are given for the vacuum case as well as for the stiff matter case. The derived solutions are the generalizations of the GRT-solutions first given by Doroshkevichet al. (1973) and Lukash (1974a). In addition we present a new BDT-stiff matter solution which has no analogy in the GRT.

Exact Bianchi type-I cosmological model with matter in Brans-Dicke theory

In this paper an exact solution of the Brans-Dicke field equations in the presence of stiff matter is obtained for the Bianchi type-I cosmological space-time. The new solution represents an anisotropic homogeneous cosmological model which tends to anisotropic expansion. The behaviour of the solution near the singularities and late stages of the expansion is discussed.