Abstract The Nobel Prize winning confirmation in 1998 of the accelerated expansion of our
Universe put into sharp focus the need of a consistent theoretical model to explain the origin …

The properties of future singularities are investigated in the universe dominated by dark
energy including the phantom-type fluid. We classify the finite-time singularities into four …

It has been suggested that a scalar field with negative kinetic energy, or “ghost,” could be the
source of the observed late-time cosmological acceleration. Naively, such theories should …

As it follows from the classical analysis, the typical final state of a dark energy universe
where a dominant energy condition is violated is a finite-time, sudden future singularity (a …

We show that a singularity can occur at a finite future time in an expanding Friedmann
universe even when ρ> 0 and ρ+ 3p> 0. Explicit examples are constructed and a simple …

The conceptual difficulties associated with a cosmological constant have led to the
investigation of alternative models in which the equation of state parameter, w= p/ρ, of the …

We report on a revision of our previous computation of the renormalized expectation value of
the stress-energy tensor of a massless, minimally coupled scalar with a quartic self …

We consider the reconstruction technique in theories with a single or multiple (phantom
and/or canonical) scalar fields. With the help of several examples, it is demonstrated …

The interplay between cosmological expansion and local attraction in a gravitationally
bound system is revisited in various regimes. First, weakly gravitating Newtonian systems …

The dark energy component of the Universe is often interpreted either in terms of a
cosmological constant or as a scalar field. A generic feature of the scalar field models is that …