Related papers: String cosmological model in the presence of a mag…
Some spatially homogeneous Bianchi type I cosmological models filled with homogeneous ``electric'' $p$-form fields are shown to mimic the never-ending oscillatory behaviour of generic string cosmologies established recently. The validity of…
We study a massive cosmic strings with BII symmetries cosmological models in two contexts. The first of them is the standard one with a barotropic equation of state. In the second one we explore the possibility of taking into account…
Systems of interacting networks of strings such as cosmic strings or quantum vortices can be approximated in a certain regime as an anisotropic fluid with an equation of state depending on a conserved flux. The equations for ideal…
The paper presents some exact solutions of Bianchi types I, III and Kantowski-Sachs cosmological models consisting of a dissipative fluid along with an axial magnetic field. A barytropic equation of state between the thermodynamic pressure…
We consider the Bianchi I geometry coupled to several species of comoving barotropic perfect fluids with a linear equation of state in the context of general relativity. The solution of the dynamics can be reduced to a quadrature, which can…
We use one of the simplest forms of the K-essence theory and we apply it to the classical anisotropic Bianchi type I cosmological model, with a barotropic perfect fluid modeling the usual matter content and with cosmological constant. The…
The dynamics of the hyperextended scalar-tensor theory in the empty Bianchi type I model is investigated. We describe a method giving the sign of the first and second derivatives of the metric functions whatever the coupling function.…
We make use of a flat, axisymmetric Bianchi I metric to investigate the effects of a magnetic field upon the dynamics of the universe for the case in which the accompanying fluid is a cosmological constant and derive two exact solutions to…
We investigate brane-worlds with a pure magnetic field and a perfect fluid. We extend earlier work to brane-worlds, and find new properties of the Bianchi type I brane-world. We find new asymptotic behaviours on approach to the singularity…
In this paper we derive some new invariant solutions of Einstein-Maxwell's field equations for string fluid as source of matter in cylindrically symmetric space-time with Variable Magnetic Permeability. We also discuss the physical and…
In this paper we have investigated an LRS Bianchi I anisotropic cosmological model of the universe by taking time varying $G$ and $\Lambda$ in the presence of bulk viscous fluid source described by full causal non-equilibrium…
A discrete symmetry of the four-dimensional string effective action is employed to derive spatially homogeneous and inhomogeneous string cosmologies from vacuum solutions of general relativity that admit two commuting spacelike Killing…
Conformally flat tilted Bianchi type V cosmological models in presence of a bulk viscous fluid and heat flow are investigated. The coefficient of bulk viscosity is assumed to be a power function of mass density. The cosmological constant is…
The asymptotic behaviour of two classes of scalar field cosmological models are studied using the theory of dynamical systems: general relativistic Bianchi models containing matter and a scalar field with an exponential potential and a…
In this work, we investigate the anisotropic Bianchi type I cosmological model in the chiral setup, in a twofold manner. Firstly, we consider a quintessence plus a k-essence like model, where two scalar fields but only one potential term is…
We study dilaton-electrodynamics in flat spacetime and exhibit a set of global cosmic string like solutions in which the magnetic flux is confined. These solutions continue to exist for a small enough dilaton mass but cease to do so above a…
Cylindrically symmetric inhomogeneous string cosmological models in presence of electromagnetic field is investigated. We have assumed that $F_{12}$ is the only non-vanishing component of $F_{ij}$. The Maxwell's equations require that…
A complete qualitative study of the dynamics of string cosmologies is presented for the class of isotopic curvature universes. These models are of Bianchi types I, V and IX and reduce to the general class of Friedmann-Robertson-Walker…
We propose a model with a U(1)_A x U(1)_B gauge symmetry which contains topological strings carrying magnetic flux under each of the U(1)s. By calculating the tension of the first few low energy strings we show that bound states, containing…
Cosmic strings are predicted in many models beyond the Standard Model of particle physics. In models which admit strings, a network of strings will inevitably be formed in a phase transition in the early universe and will persist to the…