Related papers: Superquintessence
A cosmological model with perfect fluid and self-interacting quintessence field is considered in the framework of the spatially flat Friedmann-Robertson-Walker (FRW) geometry. By assuming that all physical quantities depend on the volume…
A unified approach to quintessence and inflation is investigated with the use of a single scalar field. It is argued that successful potentials have to approximate a combination of exponential and inverse power-law decline in the limit of…
The nonminimal coupling (NMC) of the scalar field to the Ricci curvature is unavoidable in many cosmological scenarios. Inflation and quintessence models based on nonminimally coupled scalar fields are studied, with particular attention to…
The issues of quintessence and cosmic acceleration can be discussed in the framework of theories which do not include necessarily scalar fields. It is possible to define pressure and energy density for new components considering effective…
We discuss the dynamics of a quintessence model involving two coupled scalar fields. The model presents two types of solutions, namely solutions that correspond to eternal and transient acceleration of the universe. In both cases, we obtain…
Scalar field models of quintessence typically require that the expectation value of the field today is of order the Planck mass, if we want them to explain the observed acceleration of the Universe. This suggests that we should be…
Quintessential inflation utilises a single scalar field to account for the observations of both cosmic inflation and dark energy. The requirements for modelling quintessential inflation are described and two explicit successful models are…
Quintessence is a canonical scalar field introduced to explain the late-time cosmic acceleration. The cosmological dynamics of quintessence is reviewed, paying particular attention to the evolution of the dark energy equation of state w.…
We investigate cosmology with complex scalar field. It is shown that such models can describe two stages of inflation and the oscillatory regime. Thus we don't need both quintessence and $\Lambda$-term. It is enough to have single complex…
In this work it is investigated the evolution of a Universe where a scalar field, non-minimally coupled to space-time curvature, plays the role of quintessence and drives the Universe to a present accelerated expansion. A non-relativistic…
Quintessential inflation--in which a single scalar field plays the role of the inflaton and quintessence--from a sum of exponentials potential V = A (exp{5 phi}+exp{sqrt{2} phi}) or V = A (exp{5 phi}+exp{phi}) or a cosh potential V = 2A…
A generic feature of cosmic quintessence models is the possibility of significant energy density in the scalar field during the radiation dominated epoch. This possibility is even greater if the quintessence field begins in a…
In this comment, we show explicitly that the phenomenological model in which the quintessence field depends linearly on the energy density of the spatial curvature can provide acceleration for the universe, contrary to recent claims it…
The issues of quintessence and cosmic acceleration can be discussed in the framework of higher order theories of gravity. We can define effective pressure and energy density directly connected to the Ricci scalar of curvature of a generic…
The most recent cosmological data point in the direction of a cosmological constant dominated universe. A suitable candidate for providing the required acceleration is a rolling scalar field named ``quintessence''. We address the issue of…
We study the dynamics of a quintessence model based on two interacting scalar fields. The model can account for the (recent) accelerated expansion of the Universe suggested by astronomical observations. Acceleration can be permanent or…
We present a unified framework that simultaneously addresses the dynamics of early-time cosmic inflation and late-time cosmic acceleration within the context of a single scalar field non-minimally coupled to gravity. By employing an…
A novel approach to quintessential inflation model building is studied, within the framework of $\alpha$-attractors, motivated by supergravity theories. Inflationary observables are in excellent agreement with the latest CMB observations,…
Recent observations of Type Ia supernova at high redshifts establish that the dark energy component of the universe has (a probably constant) ratio between pressure and energy density $w=p/\rho=-1.02(^{+0.13}_{-0.19})$. The conventional…
The dynamics of a universe dominated by a self-interacting nonminimally coupled scalar field are considered. The structure of the phase space and complete phase portraits are given. New dynamical behaviors include superinflation…