Irreversible processes and the accelerated-decelerated phases of the Universe
arXiv:gr-qc/0404011 · doi:10.1590/S0103-97332004000600012
Abstract
A model for the Universe is proposed where it is considered as a mixture of scalar and matter fields. The particle production is due to an irreversible transfer of energy from the gravitational field to the matter field and represented by a non-equilibrium pressure. This model can simulate three distinct periods of the Universe: (a) an accelerated epoch where the energy density of the scalar field prevails over the matter field, (b) a past decelerated period where the energy density of the matter field becomes more predominant than the scalar energy density, and (c) a present acceleration phase where the scalar energy density overcomes the energy density of the matter field.
6 pages, 2 figures, to be published in Brazilian Journal of Physics