相关论文: Thermodynamically allowed phantom cosmology with v…
In a homogeneous and isotropic universe bulk viscosity is the unique viscous effect capable to modify the background dynamics. Effects like shear viscosity or heat conduction can only change the evolution of the perturbations. The existence…
In this work we present the cosmological dynamics of interacting dark energy models in the framework of particle creation mechanism. The particle creation mechanism presented here describes the true non equilibrium thermodynamics of the…
We study a closed model of a universe filled with viscous fluid and quintessence matter components. The dynamical equations imply that the universe might look like an accelerated flat Friedmann-Robertson-Walker (FRW) universe at low…
We present a novel cosmological framework that unifies matter creation dynamics with thermodynamic principles. Starting with a single-component fluid characterized by a constant equation of state parameter, $\omega$, we introduce a…
The influence of a possible non zero chemical potential $\mu$ on the nature of dark energy is investigated by assuming that the dark energy is a relativistic perfect simple fluid obeying the equation of state (EoS), $p=\omega \rho$ ($\omega…
A possible cause of the late-time cosmic acceleration is an exotic fluid with an equation of state lying within the phantom regime, i.e., $w=p/\rho <-1$. The latter violates the null energy condition, which is a fundamental ingredient in…
In this work we explore some cosmological properties coming from the particle and future horizons when are considered as candidates to model the dark energy sector within a holographic context in a flat Friedmann-Lemaitre-Robertson-Walker…
Within the context of a cosmic space whose energy source is modeled with a perfect fluid, a uniform model of Universe based on a standard FRW cosmology containing decoupled mixed matter sources namely stiff matter and cosmic dust together…
The present work deals with universe bounded by the cosmological event horizon as a thermodynamical system which is irreversible in nature.Using non-equilibrium thermodynamical approach the entropy variation on the event horizon has been…
Phantom scalar theories are widely considered in cosmology, but rarely at the quantum level, where they give rise to negative-energy ghost particles. These cause decay of the vacuum into gravitons and photons, violating observational…
We perform a study both statistical and theoretical for cosmological models of matter creation and their ability to describe effective phantom models of dark energy. Such models are beyond the $\Lambda$CDM model since the resulting cosmic…
A possible candidate for the present accelerated expansion of the Universe is ''phantom energy'', which possesses an equation of state of the form $\omega\equiv p/\rho<-1$, consequently violating the null energy condition. As this is the…
We study the thermodynamics of the universe containing perfect fluid with equation of state $p=\omega\rho,\omega$ is variable. Here we choose $\omega$ to be a function of the red shift variable $z$ and four different choices of $\omega$ has…
Dark energy with the usually used equation of state $p=w\rho$, where $w=const<0$ is hydrodynamically unstable. To overcome this drawback we consider the cosmology of a perfect fluid with a linear equation of state of a more general form…
It has been suggested that a possible candidate for the present accelerated expansion of the Universe is ''phantom energy''. The latter possesses an equation of state of the form $\omega\equiv p/\rho<-1$, consequently violating the null…
We show that in the isentropic scenario the first order thermodynamical particle creation model gives an emergent universe solution even when the chemical potential is non-zero. However there exists no emergent universe scenario in the…
In this work we discuss a general approach for the dark energy thermodynamics considering a varying equation of state (EoS) parameter of the type $\omega(a)=\omega_0+F(a)$ and taking into account the role of a non-zero chemical potential…
We consider the dynamics of a causal bulk viscous cosmological fluid filled constantly decelerating Bianchi type I space-time. The matter component of the Universe is assumed to satisfy a linear barotropic equation of state and the state…
The thermodynamic properties of a phantom fluid and accretion by a black hole were recently revisited by Pereira (2008) and Lima et al. (2008). In order to keep positive both the entropy and the temperature, those authors assumed that the…
The objective of the present work is to study a cosmological model for a spatially flat Universe whose constituents are a dark energy field and a matter field which includes baryons and dark matter. The constituents are supposed to be in…