Anisotropic and Inhomogeneous Cosmologies

ar X iv : g r - qc / 9 21 20 13 v 1 2 1 D ec 1 99 2 Inhomogeneous and anisotropic cosmologies

Asymptotic Behaviour of Inhomogeneous String Cosmologies

The asymptotic behaviour at late times of inhomogeneous axion-dilaton cosmologies is investigated. The space-times considered here admit two abelian space-like Killing vectors. These space-times evolve towards an anisotropic universe containing gravitational radiation. Furthermore, a peeling-off behaviour of the Weyl tensor and the antisymmetric tensor field strength is found. The relation to t...

Inhomogeneous M-Theory Cosmologies

Abstract We study a class of inhomogeneous and anisotropic G2 string cosmological models. In the case of separable G2 models we show that the governing equations reduce to a system of ordinary differential equations. We focus on a class of separable G2 M-theory cosmological models, and study their qualitative behaviour (a class of models with time-reversed dynamics is also possible). We find th...

Shear Waves Through Non Planar Interface Between Anisotropic Inhomogeneous and Visco-Elastic Half-Spaces

A problem of reflection and transmission of a plane shear wave incident at a corrugated interface between transversely isotropic inhomogeneous and visco-elastic half-spaces is investigated. Applying appropriate boundary conditions and using Rayleigh’s method of approximation expressions for reflection and transmission coefficients are obtained for the first and second order approximation of the...

Self-similar cosmologies in 5D: spatially flat anisotropic models

In the context of theories of Kaluza-Klein type, with a large extra dimension, we study self-similar cosmological models in 5D that are homogeneous, anisotropic and spatially flat. The “ladder” to go between the physics in 5D and 4D is provided by Campbell-Maagard’s embedding theorems. We show that the 5-dimensional field equations RAB = 0 determine the form of the similarity variable. There ar...