Induced Phantom And 5D Attractor Solution In Space-Time-Matter Theory

This thesis introduces the classical Kaluza-Klein theory and modern Kaluza-Klein theory-Space-Time-Matter theory proposed by Wesson. The second chapter indicates the dark energy cosmology including the property of dark energy, current astronomical observations of accelerating universe, several candidates of dark energy et al.In Spacetime-Matter theory we assume that the 4D induced matter of the 5D Ricci-flat bouncing cosmological solutions contains a perfect fluid as well as an induced scalar field. Then we show that the conventional 4D quintessence and phantom models of dark energy could be recovered from the 5D cosmological solutions. By using the phase-plane analysis to study the stability of evolution of the 5D models, we find that the conventional 4D late-time attractor solution is also recovered. This attractor solution shows that the scale factors of the phantom dominated universes in both the 4D and 5D theories will reach infinity in a finite time and the universes will be ended at a new kind of spacetime singularity at which everything will be annihilated. We also find that the repulsive force of the phantom may provide us with a mechanics to explain the bounce.