Study On Space-Time-Matter Theory And Brane Model

Now,cosmology is entering a precise epoch.The recent measurements of type Ia super-novae(SNe In)are the most direct evidence of accelerating expansion of the universe.To explain this puzzle,there are some models.This thesis is basing on space-time-matter(STM) theory and brane-world model.Firstly,it discusses some fundamental elements of cosmology and some simple models.Secondly,the high dimensional models are introduced.Thirdly, using(4 + 1)split the 5D Ricci-flat cosmological solutions,the 4D induced matter is derived. And then by using four energy conditions(null,weak,strong,and dominant)to pick out and study the induced matter.Subsequently,the energy conditions are used to distinguish the brahe models,and study the matter on the brane.Then,corresponding the DGP brahe cosmology and 5D Ricci-fiat cosmology,it is given that a specific geometrical property of the arbitrary integral constant I in DGP metric and the relation of arbitrary functionsμandνin a class of Ricci-flat solutions.Whereafter,the brahe model with a brahe tachyon field is studied.Finally,the global brahe cosmology is researched.