Related papers: Can the quintessence be a complex scalar field?
In quintessence scalar field theories, the presence of scaling solutions are important during the radiation and matter epoch due to having their attractor character. Usually, it is assumed that the initial conditions of the quintessence…
In this paper I shall consider various possible scalar-vector-tensor field theories which might be used to describe the Universe. After imposing numerous constraints of a physical and mathematical nature on the theories under consideration,…
We explore the dynamics of assisted quintessence, where more than one scalar field is present with the same potential. For potentials with tracking solutions, the fields naturally approach the same values; in the context of inflation this…
We discuss the implication of the introduction of an extra field to the dynamics of a scalar field conformally coupled to gravitation in a homogeneous isotropic spatially flat universe. We show that for some reasonable parameter values the…
Quintessence - the energy density of a slowly evolving scalar field - may constitute a dynamical form of the homogeneous dark energy in the universe. We review the basic idea and indicate observational tests which may distinguish…
Recent observations of near supernova show that the acceleration expansion of Universe decreases. This phenomenon is called the transient acceleration. In the second part of work we consider the 3-component Universe composed of a scalar…
Several recent works suggested the possibility of describing inflation by means of a renormalization group equation. In this paper we discuss the application of these methods to models of quintessence. In this framework a period of…
We study the cosmological evolution for a universe in the presence of a continuous tower of massive scalar fields which can drive the current phase of accelerated expansion of the universe and, in addition, can contribute as a dark matter…
Recently we proposed that the acceleration of the Universe could be due to gravity leaking to extra dimensions. This scenario gives an alternative to the cosmological constant or quintessence. In [astro-ph/0106274] the authors claimed that…
A slow-rolling scalar field (Quintessence) has been proposed as the origin of accelerating universe at present. We discuss some features of quintessence, particularly those related with the {\it flatness} of its potential. We distinguish…
We study a coupled quintessence model in which the interaction with the dark matter sector is a function of the quintessence potential. Such a coupling can arise from a field dependent mass term for the dark matter field. The dynamical…
Neutrinos interacting with the quintessence field can trigger the accelerated expansion of the Universe. In such models with a growing neutrino mass the homogeneous cosmological solution is often unstable to perturbations. We present…
We investigate whether a tachyonic scalar field, encompassing both dark energy and dark matter-like features will drive our universe towards a Big Brake singularity or a de Sitter expansion. In doing this it is crucial to establish the…
We consider the efficacy of using luminosity distance measurements of deep redshift supernovae to discriminate between two forms of dark energy, quintessence (a scalar field with canonical kinetic terms rolling down a potential) and…
A new component of the cosmic medium, a light scalar field or ''quintessence '', has been proposed recently to explain cosmic acceleration with a dynamical cosmological constant. Such a field is expected to be coupled explicitely to…
Understanding the late-time acceleration of the Universe is one of the major challenges in cosmology today. In this paper, we present a new scalar field model corresponding to a generalised axion-like potential. In fact, this model can be…
In the context of quintessence, the concept of tracking solutions allows to address the fine-tuning and coincidence problems. When the field is on tracks today, one has $Q\approx m_{\rm Pl}$ demonstrating that, generically, any realistic…
A self-consistent system of interaction nonlinear spinor and scalar fields within the scope of a BI cosmological model filled with perfect fluid is considered. The role of spinor field in the evolution of the Universe is studied. It is…
We present a new approach to quintessential inflation, in which both dark energy and inflation are explained by the evolution of a single scalar field. We start from a simple scalar potential with both oscillatory and exponential…
Observations seem to indicate that our universe is presently accelerating due to the presence of dark energy. Quintessence represents a possible way to model the dark energy. In these proceedings, we briefly review its main properties.