Theoretical and phenomenological study of non-standard cosmology.

Abstract

In this thesis, we studied two different phenomena. In the first part, the accelerated expansion of the universe without introducing the concept of dark energy was examined. We studied it in the FRW metric with perfect and non-perfect fluid, as well as the KantowskiSachs Space-Time and F (R) Gravity models. We confirmed that geometry has an impact on the accelerated expansion of the universe. In the second part, the effect of gravitational force on entanglement is explored, where the elaboration of a general formalism for quantum spin entanglement in curved space-time is presented. This formulation permits the study of different models in curved space-time. The Schwarzschild-de Sitter Space-Time was investigated as well by inspecting the role of the cosmological constant and its influence on entanglement. The Kerr and the Reissner-Nordström models are also considered, where the effect of the non-commutativity of space as well as black hole rotation on entanglement are discussed by using concurrence and the spin entanglement of a system of two spin-1/2 particles. With particularity, it contains multiple and various physical parameters, allowing for a detailed study of this purely quantum phenomenon in different frames of space and geometry or both at the same time.