Time-Dependent Dark Energy Density and Holographic DE Model with Interaction

In this article we consider holographic dark energy model with interaction and space curvature. We calculate cosmic scale factor by using the time-dependent dark energy density. Then we obtain phenomenological interaction between holographic dark energy and matter.     

Weak Gravity Conjecture and Holographic Dark Energy Model with Interaction and Spatial Curvature

In the paper, we apply the weak gravity conjecture to the holographic quintessence model of dark energy. Three different holographic dark energy models are considered: without the interaction in the non-flat universe; with interaction in the flat universe; with interaction in the non-flat universe. We find that
only in the models with the spatial curvature and interaction term proportional to the energy density of matter, it is possible for the weak gravity conjecture to be satisfied. And it seems that the weak gravity conjecture favors an open universe and the decaying of matter into dark energy.     

Interacting Entropy-Corrected Holographic Dark Energy and IR Cut-Off Length

In this paper we consider holographic dark energy model with corrected holographic energy density and show that this model may be equivalent to the modified Chaplygin gas model. Then we obtain relation between entropy corrected holographic dark energy model and scalar field models. We do these works by using choices of IR cut-off length proportional to the Hubble radius, the event horizon radius, the Ricci length, and the Granda-Oliveros length.     

Interacting agegraphic dark energy

A new dark energy model, named “agegraphic dark energy”, has been proposed recently, based on the so-called Károlyházy uncertainty relation, which arises from quantum mechanics together with general relativity. In this note, we extend the original agegraphic dark energy model by including the interaction between agegraphic dark energy and pressureless (dark) matter. In the interacting agegraphic dark energy model, there are many interesting features different from the original agegraphic dark energy model and holographic dark energy model. The similarity and difference between agegraphic dark energy and holographic dark energy are also discussed.     

Restoring holographic dark energy in brane cosmology

We present a generalized version of holographic dark energy arguing that it must be considered in the maximally subspace of a cosmological model. In the context of brane cosmology it leads to a bulk holographic dark energy which transfers its holographic nature to the effective 4D dark energy. As an application we use a single-brane model and we show that in the low energy limit the behavior of the effective holographic dark energy coincides with that predicted by conventional 4D calculations. However, a finite bulk can lead to radically different results.     

Yangian algebra in the bi-qubit system and mixed light pseudoscalar meson state

We extend the holographic Ricci dark energy model to include some direct, non-gravitational interaction between dark energy and dark matter. We consider three phenomenological forms for the interaction term Q in the model, namely, Q is taken proportional to the Hubble expansion rate and the energy densities of dark sectors (taken to be ?? _de, ?? _m, and ?? _de+?? _m, respectively). We obtain a uniform analytical solution to the three interacting models. Furthermore, we constrain the models by using the latest observational data, including the 557 Union2 type Ia supernovae data, the cosmic microwave background anisotropy data from the 7-yr WMAP, and the baryon acoustic oscillation data from the SDSS. We show that in the interacting models of the holographic Ricci dark energy, a more reasonable value of ?? _m0 will be obtained, and the observations favor a rather strong coupling between dark energy and dark matter.     

Evolution of Holographic Dark Energy in Interacting Modified Chaplygin Gas Model

We investigate the modified Chaplygin gas （MCG） with interaction between holographic dark energy proposed by Li and dark matter. In this model, evolution of the universe is described in detail, which is from deceleration to acceleration. Specifically, the evolutions of related cosmological quantities such as density parameter, the equation of state of holographic dark energy, deceleration parameter and transition redshift are discussed. Moreover, we also give their present values which are consistent with the lately observations. Furthermore, the results given by us show such a model can accommodate a transition of the dark energy from a normal state wx 〉 -1 to ωx 〈 -1 phantom regimes.     

Exploring interacting holographic dark energy in a perturbed universe with parameterized post-Friedmann approach

The model of holographic dark energy in which dark energy interacts with dark matter is investigated in this paper. In particular, we consider the interacting holographic dark energy model in the context of a perturbed universe, which was never investigated in the literature. To avoid the large-scale instability problem in the interacting dark energy cosmology, we employ the generalized version of the parameterized post-Friedmann approach to treating the dark energy perturbations in the model. We use the current observational data to constrain the model. Since the cosmological perturbations are considered in the model, we can then employ the redshift-space distortions (RSD) measurements to constrain the model, in addition to the use of the measurements of expansion history, which has never been done in the literature. We find that, for both the cases with \(Q=\beta H\rho _\mathrm{c}\) and with \(Q=\beta H_0\rho _\mathrm{c}\), the interacting holographic dark energy model is more favored by the current data, compared to the holographic dark energy model without interaction. It is also found that, with the help of the RSD data, a positive coupling \(\beta \) can be detected at the \(2.95\sigma \) statistical significance for the case of \(Q=\beta H_0\rho _\mathrm{c}\).     

Holographic dark energy in a cyclic universe

In this paper we study the cosmological evolution of the holographic dark energy in a cyclic universe, generalizing the model of holographic dark energy proposed by Li. The holographic dark energy with c<1 can realize a quintom behavior; namely, it evolves from a quintessence-like component to a phantom-like one. The holographic phantom energy density grows rapidly and dominates the late-time expanding phase, helping to realize a cyclic universe scenario in which the high energy regime is modified by the effects of quantum gravity, causing a turn-around (and a bounce) of the universe. The dynamical evolution of holographic dark energy in the regimes of low energy and high energy is governed by two differential equations, respectively. It is of importance to link the two regimes for this scenario. We propose a link condition giving rise to a complete picture of holographic evolution of a cyclic universe.     

Holographic Gas as Dark Energy

We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the holographic entropy can be obtained by modifying degeneracy. We calculate thermodynamical quantities and investigate stability of the holographic gas. When applying to cosmology, we find that the holographic gas behaves as holographic dark energy, and the parameter c in holographic dark energy can be calculated from our model. Our model of holographic gas generally predicts c 〈 1, implying that the fate of our universe is phantom-like.     

Holographic Dark Energy Density and JBP Parametrization

In this article we consider the holographic dark energy density. We study dark energy density in Universe with arbitrary spatially curvature described by the Friedmann-Robertson-Walker metric. We use Jassal-Bagla-Padmanabhan parametrization to specify dark energy density.     

Holographic Dark Energy Density

In this article we consider the cosmological model based on the holographic dark energy. We study dark energy density in Universe with arbitrary spatially curvature described by the Friedmann-Robertson-Walker metric. We use Chevallier-Polarski-Linder parametrization to specify dark energy density.     

Holographic Dark Energy in Higher Derivative Gravity with Varying Gravitational Constant

In this paper we investigate the holographic dark energy scenario in higher derivative gravity with a varying gravitational constant. We introduce a kind of energy density from higher derivative gravity which has role of the same as holographic dark energy. We obtain the exact differential equation , which determine the evolution of the dark energy density based on varying gravitational constant G. We also find out a cosmological application of our work by evaluating a relation for the equation of state of dark energy for low redshifts containing varying G correction.     

Holographic dark energy with varying gravitational constant

We investigate the holographic dark energy scenario with a varying gravitational constant, in flat and non-flat background geometry. We extract the exact differential equations determining the evolution of the dark energy density-parameter, which include G-variation correction terms. Performing a low-redshift expansion of the dark energy equation of state, we provide the involved parameters as functions of the current density parameters, of the holographic dark energy constant and of the G-variation.     

Inflation via logarithmic entropy-corrected holographic dark energy model

We study the inflation in terms of the logarithmic entropy-corrected holographic dark energy (LECHDE) model with future event horizon, particle horizon, and Hubble horizon cut-offs, and we compare the results with those obtained in the study of inflation by the holographic dark energy HDE model. In comparison, the spectrum of primordial scalar power spectrum in the LECHDE model becomes redder than the spectrum in the HDE model. Moreover, the consistency with the observational data in the LECHDE model of inflation constrains the reheating temperature and Hubble parameter by one parameter of holographic dark energy and two new parameters of logarithmic corrections.     

Kaluza–Klein cosmology with modified holographic dark energy

We investigate the compact Kaluza–Klein cosmology in which modified holographic dark energy is interacting with dark matter. Using this scenario, we evaluate equation of state parameter as well as equation of evolution of the modified holographic dark energy. Further, it is shown that the generalized second law of thermodynamics holds without any constraint.     

Quintessence Reconstruction of Interacting HDE in a Non-Flat Universe

In this paper we consider quintessence reconstruction of interacting holographic dark energy in a non-fiat background. As system＇s IR cutoff we choose the radius of the event horizon measured on the sphere of the horizon, defined as L = at（t）. To this end we construct a quintessence model by a real, single scalar field. Evolution of the potential, V（φ）, as well as the dynamics of the scalar field, φ, is obtained according to the respective holographic dark energy. The reconstructed potentials show a cosmological constant behavior for the present time. We constrain the model parameters in a fiat universe by using the observational data, and applying the Monte Carlo Markov chain simulation. We obtain the best fit values of the holographic dark energy model and the interacting parameters as c=1.0576-0.6632-0.6632^＋0.3010＋0.3052 and ζ =0.2433-0.2251-.2251^＋0.6373＋0.6373 , respectively. From the data fitting results we also find that the model can cross the phantom line in the present universe where the best fit value of the dark energy equation of state is WD=-1.2429.