We consider the viability of dark energy (DE) models in the framework of the scalar–tensor
theory of gravity, including the possibility of having a phantom DE at small redshifts z as …

We study in this paper the perturbations of the quintom dark energy model and the effects of
quintom perturbations on the current observations. Quintom describes a scenario of dark …

We construct a family of viable scalar-tensor models of dark energy (DE) which possess a
phase of late-time acceleration preceded by a standard matter era, while at the same time …

The difference between the vacuum energy of quantum fields in Minkowski space and in a
Friedmann-Robertson-Walker universe might be related to the observed dark energy. The …

We study a phenomenological dark energy model which is rooted in the Veneziano ghost of
QCD. In this dark energy model, the energy density of dark energy is proportional to Hubble …

Recently, many dark energy models whose equation-of-state parameter can cross the
phantom divide w de=-1 have been proposed. In a previous paper [H. Wei, RG Cai, and DF …

One of the puzzles of the dark energy problem is the (first) cosmological coincidence
problem, namely, why does our Universe begin the accelerated expansion recently? Why …

If Newton's constant G evolves on cosmological timescales as predicted by extended gravity
theories then Type Ia supernovae (SnIa) cannot be treated as standard candles. The …

In dynamical system describing evolution of universe with the flat Friedmann–Robertson–
Walker symmetry filled with barotropic dust matter and non-minimally coupled scalar field …

We present a simple model in which the weak energy condition is violated for spatially
homogeneous, slowly evolving fields. The excitations in Minkowski space in an external field …