一个4+1维宇宙模型

我们讨论的4+1维宇宙模型是通常的四维时空和一个紧致的一维内禀空间的直积空间。我们假定四维时空的能量密度是以辐射为主的,而内禀子空间的能动张量是一个阶跃函数。通过求解五维的Einstein场方程得到前四维时空由de-Sitter解过渡到标准模型的辐射为主解,与此同时内禀子空间的尺度由减幅振荡过渡到为按t的负幂次收缩而趋于一常量。 关键词：

A(4 + 1)-DIMENSIONAL COSMOLOGICAL MODEL

The (4+1)-dimensional cosmological model discussed in this paper is a direct product of the usual 4-dimensional spacetime and a. 1-dimensional compaetified internal space. The energy density of the 4-dimensional spacetime is supposed to be dominated by incoherent radiation and the energy-momentum tensor of the internal subspace is a step function. By solving the 5-dimensional Einstein field equations without cosmolog-ical term we get the de-Sitter solution to describe the usual spacetime and at a certain time it changes to the radiation-dominated solution for standard model, and the size of the internal subspace changes with time in a form of oscillation with amplitude attenuating and then contracts to a constant.