Two cosmological models with non-phantom matter having the same expansion of the universe as phantom cosmologies are constructed. The first model is characterized by the evolving gravitational “constant” G and a dark energy component with a non-conserved energy-momentum tensor. The second model includes two interacting components, the dark energy component and the matter component. Closed form solutions are obtained for the constant values of model parameters and constraints on the parameters of each model from cosmological observations are outlined. For both models it is explicitly shown how the components of each model produce the expansion of the universe characteristic of phantom cosmologies, despite the absence of phantom energy. These findings stress the interpretation of phantom energy as an effective description of the more complex dynamics of non-phantom matter.
European Physical Journal C
- Pub Date:
- August 2004
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology;
- High Energy Physics - Theory
- v1: 9 pages. v2: references added, minor changes in the text. v3: minor changes, references added and updated, version to appear in Eur. Phys. J. C