Solutions Of Relativistic Field Equations Research Articles

Horizon free eternally collapsing anisotropic radiating star

We present a class of exact solutions of relativistic field equations for a shear-free spherically symmetric anisotropic fluid undergoing radial heat flow. The interior metric fulfilled all the relevant physical and thermodynamic conditions and matched with Vaidya exterior metric over the boundary. Initially mass and radius are infinite and finally they both contract to a point as time approaches zero without forming an event horizon at the boundary. Since, for this class of models, the collapse begins at infinite past and continues in the finite present, such models may be considered as examples of “Eternal Collapse”. For this given model, the luminosity is time independent so it radiates with uniform rate throughout the collapse process and the rate of collapse increases in comparison to isotropic case.

Collapsing shear-free radiating fluid spheres

We present a new class of exact solutions of relativistic field equations for a collapsing spherically symmetric shear-free isotopic fluid undergoing radial heat flow. The interior solutions are matched with Vaidya exterior metric over the boundary. Initially the interior solutions represent a static configuration of perfect fluid which then gradually starts evolving into radiating collapse.

Higher spin fields in Siegel space, currents and theta functions

Dynamics of four-dimensional massless fields of all spins is formulated in the Siegel space of complex $4\times 4$ symmetric matrices. It is shown that the unfolded equations of free massless fields, that have a form of multidimensional Schrodinger equations, naturally distinguish between positive- and negative-frequency solutions of relativistic field equations, i.e. particles and antiparticles. Multidimensional Riemann theta functions are shown to solve massless field equations in the Siegel space. We establish the correspondence between conserved higher-spin currents in four-dimensional Minkowski space and those in the ten-dimensional matrix space. It is shown that global symmetry parameters of the current in the matrix space should be singular to reproduce a nonzero current in Minkowski space. The $\D$-function integral evolution formulae for 4d massless fields in the Fock-Siegel space are obtained. The generalization of the proposed scheme to higher dimensions and systems of higher ranks is considered.

RELATIVISTIC SUPERDENSE STAR MODELS OF PSEUDO SPHEROIDAL SPACE–TIME

The physically viable models of compact stars like SAX (J1808.4-3658) can be obtained using Vaidya–Tikekar ansatz prescribing spheroidal geometry for their interior space–time. We discuss here the suitability of an alternative ansatz in this context. The models of superdense star are proposed using a general three parameter family of solutions of relativistic field equations obtained adopting the alternative ansatz. The setup is shown to admit physically viable models of superdense stars and strange matter stars such as Her. X-1.

Two-soliton solutions of relativistic field equations

Existence of solutions converging fort → - ∞ to a superposition of two solitons is shown for a class of scalar, relativistic, field equations in two-dimensional space-time.

On the Non-Existence of Regular Stationary Solutions of Relativistic Field Equations

On the Non-Existence of Regular Stationary Solutions of Relativistic Field Equations