We review in detail a number of approaches that have been adopted to try and explain the
remarkable observation of our accelerating universe. In particular we discuss the arguments …

Recent cosmological observations suggest the existence of a positive cosmological constant
Λ with the magnitude Λ (Gℏ/c3)≈ 10− 123. This review discusses several aspects of the …

We present a detailed study of cosmological effects of homogeneous tachyon matter
coexisting with nonrelativistic matter and radiation, concentrating on the inverse square …

We study the general features of a dynamics of a phantom field in the cosmological context.
In the case of an inverse coshyperbolic potential, we demonstrate that the phantom field can …

I review the problem of dark energy focussing on cosmological constant as the candidate
and discuss what it tells us regarding the nature of gravity. Section 1 briefly overviews the …

We place observational constraints on a coupling between dark energy and dark matter by
using 71 Type Ia supernovae (SNe Ia) from the first year of the five-year Supernova Legacy …

In this paper we analyze the cosmological dynamics of phantom field in a variety of
potentials unbounded from above. We demonstrate that the nature of future evolution …

Recent cosmological observations suggest that nearly seventy per cent of the energy
density in the universe is unclustered and has negative pressure. Several conceptual issues …

We discuss the model consisting of tachyon which may have the negative kinetic energy
plus scalar phantom and plus conformal quantum matter. It is demonstrated that such a …

A cosmological model that aims at solving the coincidence problem should show that dark
energy and dark matter follow the same scaling solution from some time onward. At the …