相关论文: Axion Phantom Energy
We study a dark energy scenario in the presence of a tachyon field $\phi$ with potential $V(\phi)$ and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asymptotic behavior of the quantity…
An oscillating universe cycles through a series of expansions and contractions. We propose a model in which ``phantom'' energy with a supernegative pressure ($p < - \rho$) grows rapidly and dominates the late-time expanding phase. The…
This paper is devoted to some simple approach based on general physics tools to describe the physical properties of a hypothetical particle which can be the source of dark energy in the Universe known as phantom. Phantom is characterized by…
There has been a recent spate of papers on the Cosmic Horizon, an apparently fundamental, although unrecognised, property of the universe. The misunderstanding of this horizon, it is claimed, demonstrates that our determination of the…
Is there an absolute cosmic electric potential?. The recent discovery of the accelerated expansion of the universe could be indicating that this is certainly the case. In this essay we show that the consistency of the covariant and gauge…
We consider a higher dimensional gravity theory with a negative kinetic energy scalar field and a cosmological constant. We find that the theory admits an exact cosmological solution for the scale factor of our universe. It has the feature…
The fate of our universe is an unceasing topic of cosmology and the human being. The discovery of the current accelerated expansion of the universe significantly changed our view of the fate of the universe. Recently, some interesting…
It is widely assumed that the observed universe is accelerating due to the existence of a new fluid component called dark energy. In this article, the thermodynamics consequences of a nonzero chemical potential on the dark energy component…
To explain the acceleration of the cosmological expansion researchers have considered an unusual form of mass-energy generically called dark energy. Dark energy has a ratio of pressure over mass density which obeys $w=p/\rho <-1/3$. This…
In this brief review, we examine the theoretical consistency and viability of phantom dark energy. Almost all data sets from cosmological probes are compatible with dark energy of the phantom variety (i.e., equation-of-state parameter…
A central object in any axionic theory is its periodic potential, which is typically generated by instantons. The goal of this paper is to understand what physically happens to the theory when we lose control of the potential's instanton…
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 generically depends upon the steepness of the phantom potential and…
Holographic dark energy models have been recently suggested which most clearly show that accelerating cosmology appears to be incompatible with mathematically consistent formulations of fundamental theories such as string/M theories. In…
If the Hartle-Hawking wave function is the correct boundary condition of our universe, the history of our universe will be well approximated by an instanton. Although this instanton should be classicalized at infinity, as long as we are…
In this work, I have considered that the universe is filled with normal matter and phantom field (or tachyonic field). If the universe is filled with scalar field, Ellis et al have shown that emergent scenario is possible only for $k=+1$…
In this paper we study the behavior of the multi-field in phantom inflation, when massive scalar fields work collectively, in which the scale factor is a power law. We evaluate its parameter values by applying certain constraints on our…
An oscillating universe cycles through a series of expansions and contractions. We propose a model in which ``phantom'' energy with $p < -\rho$ grows rapidly and dominates the late-time expanding phase. The universe's energy density is so…
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 classes and explicitly present the models which give rise…
We propose a toy model of Dark Energy in which the degrees of freedom currently dominating the energy density of the universe are described by a pseudo-scalar "axion field" linearly coupled to the Pontryagin density, $ \text{tr}(F \wedge…
We investigate the cosmological evolution in a universe governed by the extended, varying-mass, nonlinear massive gravity, in which the graviton mass is promoted to a scalar-field. We find that the dynamics, both in flat and open universe,…