Model of the universe including dark energy accounted for by both a quintessence field and a (negative) cosmological constant

Abstract

In this work we present a model of the universe in which dark energy is modelled explicitely with both a dynamical quintessence field and a cosmological constant. Our results confirm the possibility of a collapsing universe (for a given region of the parameter space), which is necessary for an adequate definition of string theory. We have also reproduced the measurements of modulus distance from supernovae with good accuracy.

Inflection point quintessence

“…This is of interest because an eternally accelerating universe presents a problem for string theory, inasmuch as the S matrix in this case is ill defined [32,33]. Consequently, some effort has gone into the development of models in which the observed acceleration is a transient phenomenon [34][35][36][37][38][39][40][41][42][43]. Our model represents another example of this sort of transient acceleration for the case in which evolves through the inflection point.…”

Nonlinear spinor fields in Bianchi type-VI0 spacetime

“…The models with Λ-term [3][4][5], quintessence [6][7][8][9][10][11], Chaplygin gas [12][13][14][15][16][17][18][19] etc. are among the most studied ones, though some other models of dark energy are also proposed.…”

Quinstant dark energy predictions for structure formation

“…This seems to be the case for all studied models of quinstant dark energy (Cardenas et al 2002a(Cardenas et al , 2002c(Cardenas et al , 2003Cardone et al 2008). There are other cosmological models of composite dark energy having stiff-matter domination as an attractor in the past, but usually they would not be global attractors, but local.…”

“…We investigate spatially flat, homogeneous and isotropic cosmological models (Cardenas et al 2003;Cardone et al 2008) filled with three non-interacting components: pressureless matter (dust), a scalar field φ and a negative cosmological constant . We first consider the potential introduced by Rubano and Scudellaro (2002); Cardenas et al (2002b):…”

“…In that paper we worked with a class of dark energy models which could be dubbed quinstant dark energy, as this ingredient is considered to be a composite of a quintessence scalar field and a (negative) cosmological constant. We refer the interested reader to (Cardenas et al 2002a(Cardenas et al , 2002c(Cardenas et al , 2003Cardone et al 2008) for details on quinstant dark energy.…”