Abstract
In the context of Big Rip cosmology, dark energy characterized by a Friedmann background with an equation of state parameter w < −1 exhibits divergent behavior. This thesis modifies the Friedmann equation by incorporating Unruh radiation, which generates radiation at the event horizon. The density of Unruh radiation is assumed to be proportional to the fourth power of the Hubble parameter, making the contribution from radiation production significant at late times. We study results for various values of the radiation density parameter ΩH, maintaining a temperature T«1 K, as the acceleration range is ≈ 2 − 200 in units cH0. Even in a universe with a low Unruh temperature, including a radiation term imposes a limit on the Hubble parameter, leading to a scenario where both the Hubble parameter and the event horizon become complex before the scale factor grows sufficiently for the Unruh radiation density to dominate
Supervisor: Professor Øystein Elgarøy, Institute of Theoretical Astrophysics, UiO
Intern. assessor: Professor Boris V. Gudiksen, Institute of Theoretical Astrophysics, UiO
Extern. assessor: Professor Anders Tranberg, Department of Mathematics and Physics, UiS