Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Hawking Radiation and Black Hole Gravitational Back Reaction - A Quantum Geometrodynamical Simplified ModelPublication . Marto, JoãoThe purpose of this paper is to analyse the back reaction problem, between Hawking radiation and the black hole, in a simplified model for the black hole evaporation in the quantum geometrodynamics context. The idea is to transcribe the most important characteristics of the Wheeler-DeWitt equation into a Schrödinger’s type of equation. Subsequently, we consider Hawking radiation and black hole quantum states evolution under the influence of a potential that includes back reaction. Finally, entropy is estimated as a measure of the entanglement between the black hole and Hawking radiation states in this model.
- A varying dark energy effective speed of sound parameter in the phantom UniversePublication . Albarran, Imanol; Bouhmadi Lopez, Mariam; Marto, JoãoWe analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, c2sd, on the cosmological perturbations of three phantom DE models. Each of these models induce a particular abrupt future event known as Big Rip (BR), Little Rip (LR), and Little Sibling of the Big Rip (LSBR). In this class of abrupt events, all the bound structures in the Universe would be ripped apart at a finite cosmic time. We compute the evolution of the perturbations, fσ8 growth rate and forecast the current matter power spectrum. We vary the c2sd parameter in the interval [0, 1] and compute the relative deviation with respect c2sd=1. In addition, we analyse the effect of gravitational potential sign flip that occurs at very large scale factors as compared with the current one.