Holographic Ricci Dark Energy Model Research Articles

Diagnostic approaches for interacting generalized holographic Ricci dark energy models

In this paper, we present an analytical solution for the interacting generalized holographic dark energy model, assuming a linear interaction rate between dark energy and dark matter. We determine the equation of state parameter, the generalized holographic Ricci dark energy density, the matter density, and the deceleration parameter. By analyzing the behavior of these cosmological parameters, we demonstrate that our model aligns with recent observations and reproduces the late-time accelerated expansion of the Universe. To compare our model with the ΛCDM model, we use various diagnostic tools including statefinder, Om(z)-diagnostic, statefinder hierarchy, growth rate analysis, and ωH-ωH′ plane. We also analyze the stability of the model by examining the speed of sound. These methods show that the dynamics of the Universe remain very close to that of the standard cosmological model.

Modified holographic Ricci interacting dark energy models: dynamical system analysis and Bayesian comparison

We perform a dynamical system analysis and a Bayesian model selection for a new set of interacting scenarios in the framework of modified holographic Ricci dark energy (MHR-IDE) models. The dynamical analysis shows a modified radiation epoch and a late-time attractor corresponding to an accelerated phase of holographic dark energy. In the Bayesian comparison, we use a combination of background data including type Ia supernovae, cosmic chronometers, the local value of the Hubble constant, baryon acoustic oscillations, and cosmic microwave background data. We find evidence against all the MHR-IDE scenarios studied in comparison with the Λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varLambda $$\\end{document}CDM when the full joint analysis is considered.

Bianchi type II modified holographic Ricci dark energy model in Barber’s self-creation theory of gravitation

In this paper, we studied a spatially homogeneous and anisotropic Bianchi type II space-time in the presence of matter and modified holographic Ricci dark energy in Barber’s second self-creation theory of gravitation. We obtained exact solution of the field equations by assuming ( i) a special law of variation of the mean Hubble parameter and ( ii) the component [Formula: see text] of the shear tensor [Formula: see text] is proportional to the expansion scalar in the model. Some physical and dynamical parameters were determined and their significant roles are discussed with respect to cosmic evolution of the universe. We observe that the model is consistent with modern cosmological observational data.

A Note on Varying G and Λ in Chern–Simons Modified Gravity

We have considered the holographic dark energy and modified holographic Ricci dark energy models to analyze the time-dependent gravitational constant G(t) and cosmological constant Λ(t) in the context of Chern–Simons modified gravity theory. The FRW metric is used to examine the physical and kinematical properties of these models, which predicted the accelerated expansion phase of universe. Further, the Λ(t) showed increasing trends while G(t) showed decreasing trends for both cases. Finally, the range −1.99×10−10yr−1≤G˙G≤0 was estimated mathematically, which is similar to the results obtained from observational data.

Scrutinizing various phenomenological interactions in the context of holographic Ricci dark energy models

In this paper, we examine two types of interacting holographic dark energy model using Pantheon supernova data, BAO BOSS DR12, CMB Planck 2015, fgas (gas mass fraction) and SZ/Xray (Sunyaev–Zeldovich effect and X-ray emission) data from galaxy clusters (GC). In particular, we considered the Holographic Ricci dark energy and Extended holographic Ricci dark energy models. During this analysis, we considered seven types of phenomenological interaction terms (three linear and four non-linear) Q_1=3Hbleft( rho _{D}+rho _mright) , Q_2=3Hbrho _{D}, Q_3=3Hbrho _{m}, Q_4=3Hbleft( rho _{D}+frac{rho _{D}^2}{rho _{D}+rho _m}right) , Q_5=3Hbleft( rho _{m}+frac{rho _{m}^2}{rho _{D}+rho _m}right) , Q_6=3Hbleft( rho _{D}+rho _{m}+frac{rho _{D}^2}{rho _{D}+rho _m}right) , Q_7=3HbBig (rho _{D}+rho _{m}+frac{rho _{m}^2}{rho _{D}+rho _m}Big ) respectively. To find the best model we apply Bayesian Inference (BI) and use the Lambda CDM as the referring model for comparison. Using the Bayesian Evidence model selection method we note that the Q_3 and Q_5 interaction terms are favored by observational data among the other ones. The obtained results also demonstrated that the evidence from the Bayesian inference method against the considered types of holographic Ricci dark energy model is strong since the Lambda CDM is considered as the reference model and also the Lambda CDM is preferred over the models. We also observed that the values of the deceleration parameter and the transition redshift for all models are compatible with the latest observational data and Planck 2015. In addition, we studied the jerk parameter for all models. Using our modified CAMB code, we observed that the interacting models suppress the CMB spectrum at low multipoles and enhances the acoustic peaks.

Cosmological Analysis of Modified Holographic Ricci Dark Energy in Chern-Simons Modified Gravity

In this paper, we study the cosmological analysis of the modified holographic Ricci dark energy model and reconstruct different scalar field models in the context of Chern-Simons modified gravity. We investigate the deceleration parameter, which shows that the universe is in the accelerating expansion phase. The equation of state parameter in this case also favors the fact that dark energy is the dominant component of universe, which is responsible for the accelerated expansion. A number of scalar fields, such as quintessence, tachyon, K-essence, and dilaton models, are reconstructed using modified holographic Ricci dark energy model in the context of dynamical CS modified gravity. The quintessence and K-essence models represent exponentially increasing behaviors, while tachyon model shows decreasing behavior. Unfortunately, the dilaton model has no numerical solution for modified holographic Ricci dark energy model in the framework of dynamical Chern-Simons modified gravity.

A modified holographic Ricci dark energy model in f (R, T) theory of gravity

In the present paper, we studied the Bianchi type-V cosmological model in the presence of \(f\left( {R,T} \right) \) Theory of Gravity using modified Holographic Ricci Dark Energy. To compute dynamical cosmological parameters, we used the relation between pressure and energy density \(p_\Lambda =\omega _\Lambda \rho _\Lambda \). We have also discussed the physical and geometrical properties of the model in detail.

Holographic Ricci Dark Energy with Constant Bulk Viscosity in f(R,T) Gravity

The holographic Ricci dark energy (HRDE) model is studied with bulk viscosity in modified f(R, T) gravity theory. We consider a universe filled with bulk viscous HRDE and pressureless dark matter. We obtain exact solutions and study the evolution of the scale factor and deceleration parameter and their transition from decelerated to accelerated expansion of the universe. The bulk viscosity coefficient is assumed to be constant. The behaviors concerning the cosmic expansion depend on the coupling parameter of f(R, T) and bulk viscous term. We apply two geometric diagnostics, the statefinder {r, s} and Om(z), to discriminate HRDE model from the ΛCDM model. We plot the evolution trajectories in the statefinder plane and Om(z) plane. We find that the viscous HRDE model behaves like quintessence at small values of the bulk-viscous term and like a Chaplygin gas at large values of the bulk-viscous term. However, the model approaches ΛCDM at late times of the evolution of the universe. We explore the obvious violation of energy-momentum conservation in f(R, T) gravity and provide a thermodynamic interpretation of extra terms generated by the nonminimal geometry-matter coupling describing particle production. We observe that the current acceleration of our universe is well explained with bulk viscosity.

Ricci dark energy model with bulk viscosity

In order to explore the possibility of bulk viscosity as a possible candidate of dark energy to explain the accelerating universe, we investigate the dissipative processes in the holographic Ricci dark energy (HRDE) model within the framework of the standard Eckart theory of relativistic thermodynamics. We assume that the flat Friedmann-Robertson-Walker universe is filled with pressureless dark matter and viscous HRDE. We obtain the exact solutions of non-viscous and viscous HRDE models, respectively. We plot the evolution of the scale factor and deceleration parameter to observe the transition phase in the viscous case. We also discuss two geometrical diagnostics, namely the statefinder and Om to discriminate from other existing dark energy models. In the non-viscous HRDE model, the power-law form of expansion is obtained which gives the constant deceleration parameter and statefinder pair. It does not show phase transition. In the viscous HRDE model, we consider all possible forms of bulk viscous coefficient (with constant or general form of viscous terms) and discuss the cosmological evolution in detail. We obtain the exponential expansion of the scale factor which gives the time-dependent deceleration parameter and statefinder pair. The model shows the transition from the decelerated phase to the accelerated phase depending on the values of the viscous term. It starts to accelerate in the past for large values of the viscous term. The trajectory of the statefinder pair shows that for small values of the viscous term, the trajectory is curved and starts from quintessence in early time and approaches to $\Lambda$ CDM model in late time. It is also observed that for large values of the viscous term, it behaves like the Chaplygin gas in early time but approaches to $\Lambda$ CDM model in late time. We also plot the trajectory of the deceleration parameter, statefinder pair and Om with the model parameter to observe the evolutionary behavior of the universe. It also shows a similar behavior except for the fact that it only behaves as quintessence in the past but approaches to $\Lambda$ CDM or the steady state model in late time. The results of viscous HRDE models show that the recent acceleration is well explained with the viscous term.

FRW type Kaluza\u2013Klein modified holographic Ricci dark energy models in Brans\u2013Dicke theory of gravitation

In this paper, we investigate non-Ricci, non-compact Friedmann–Robertson–Walker type Kaluza–Klein cosmology in the presence of pressureless matter and modified holographic Ricci dark energy in the frame work of Brans and Dicke (Phys Rev 124:965, 1961) scalar–tensor theory of gravitation. We solve the field equations of this theory using a hybrid expansion law for the five dimensional scale factor. We have also used a power law and a form of logarithmic function of the scale factor for the Brans–Dicke scalar field. Consequently, we obtain two interesting cosmological models of the Kaluza–Klein universe. We have evaluated the cosmological parameters, namely, the equation of state parameter, the deceleration parameter, and the density parameters. To check the stability of our models we use the squared speed of sound. Some well-known cosmological (omega _{de}–omega ^{prime }_{de} and statefinder) planes are constructed for our models. We have also analyzed the physical behavior of these parameters through graphical representation. It is observed that the FRW type Kaluza–Klein dark energy models presented are compatible with the present day cosmological observations.

Dynamics of axially symmetric anisotropic modified holographic Ricci dark energy model in Brans-Dicke theory of gravitation

In this paper, we have derived field equations of Brans-Dicke (Phys. Rev. 124, 925 (1961)) theory of gravitation with the help of an axially symmetric anisotropic Bianchi-type space-time in the presence of dark matter and anisotropic modified holographic Ricci dark energy. We have presented a cosmological model solving the field equations. We have used i) the hybrid expansion law, ii) a relation between metric potentials and iii) the modified holographic Ricci dark energy defined by Chen and Jing (Phys. Lett. B 679, 144 (2009)) to solve the field equations. We have determined the cosmological parameters, namely, EoS parameter, matter energy density, anisotropic dark energy density, Skewness parameter, deceleration and jerk parameters. A detailed physical discussion of these dynamical parameters is presented through a graphical representation. We observe that we have a quintessence model which exhibits a smooth transition from decelerated phase to an accelerated phase of the universe. This situation is quite in agreement with the scenario of modern cosmology.

Plane symmetric modified holographic Ricci dark energy model in Saez-Ballester theory of gravitation

Abstract The present work is devoted to investigation of non-static plane symmetric universe filled with matter and anisotropic modified holographic Ricci dark energy components within the framework of a scalar-tensor theory formulated by Saez and Ballester (1986). To get the determinate solution of the model we have used scalar expansion proportional to the shear scalar, linearly varying deceleration parameter and energy density of modified holographic Ricci dark energy. We study the equation of state parameter ( ω Λ ) , deceleration parameter (q), squared speed of sound ( v s 2 ) and ω Λ - ω Λ ′ and r - s planes for our dark energy model. The equation of state parameter provides a quintom-like behavior of the universe. The r - s plane corresponds to Λ CDM limit, Chaplygin and phantom regions, whereas ω Λ - ω Λ ′ trajectories correspond to both thawing and freezing regions.

Kantowski–Sachs modified holographic Ricci dark energy model in Saez–Ballester theory of gravitation

We have considered Kantowski–Sachs space–time in the presence of matter and anisotropic modified holographic Ricci dark energy components in the scalar–tensor theory of gravitation formulated by Saez and Ballester (Phys. Lett. A, 113, 467, 1986) and derived the field equations of the theory. We have used (i) hybrid expansion law proposed by Akarsu et al. (JCAP, 022, 2014), (ii) a relation between metric potentials, and (iii) modified holographic Ricci dark energy density given by Chen and Jing (Phys. Lett. B, 679, 144, 2009) to obtain an exact solution of the field equations that describes a Kantowski–Sachs holographic modified Ricci dark energy universe in this theory. Physical and kinematical parameters are also computed and their physical behavior is discussed.

More on the holographic Ricci dark energy model: smoothing Rips through interaction effects?

The background cosmological dynamics of the late Universe is analysed on the framework of a dark energy model described by an holographic Ricci dark energy component. Several kind of interactions between the dark energy and the dark matter components are considered herein. We solve the background cosmological dynamics for the different choices of interactions with the aim to analyse not only the current evolution of the universe but also its asymptotic behaviour and, in particular, possible future singularities removal. We show that in most of the cases, the Big Rip singularity, a finger print of this model in absence of an interaction between the dark sectors, is substituted by a de Sitter or a Minkowski state. Most importantly, we found two new future bouncing solutions leading to two possible asymptotic behaviours, we named Little Bang and Little Sibling of the Big Bang. At a Little Bang, as the size of the universe shrinks to zero in an infinite cosmic time, the Hubble rate and its cosmic time derivative blow up. In addition, at a Little sibling of the Big Bang, as the size of the universe shrinks to zero in an infinite cosmic time, the Hubble rate blows up but its cosmic time derivative is finite. These two abrupt events can happen as well in the past.

Bianchi type-V modified holographic Ricci dark energy model in self-creation theory of gravitation

Anisotropic and spatially homogeneous Bianchi type-V space–time is considered in the presence of matter and anisotropic dark energy in Barber’s (Gen. Relativ. Gravit. 14, 117. (1982)) second self-creation theory of gravitation. An anisotropic modified holographic Ricci dark energy model is presented using linearly varying deceleration parameter (Akarsu and Dereli. Int. J. Theor. Phys. 51, 612 (2012)), energy density of modified holographic Ricci dark energy, and the relation between the metric potentials. Some physical and kinematical properties of the model are discussed graphically by choosing suitable values of the parameters, which are found to be in good agreement with modern cosmological observational data.

Bianchi type-V modified holographic Ricci dark energy models in Saez–Ballester theory of gravitation

We have investigated Bianchi type-V universe filled with matter and modified holographic Ricci dark energy in a scalar–tensor theory proposed by Saez–Ballester (Phys. Lett. A, 113, 467 (1986)). To get a determinate solution, we have used (i) hybrid expansion law (Akarsu et al. JCAP, 01, 022 (2014)), (ii) varying deceleration parameter (Mishra et al. Int. J. Theor. Phys. 52, 2546 (2013)), and (iii) linearly varying deceleration parameter (Akarsu and Dereli. Int. J. Theor. Phys. 51, 612 (2012)). The various physical and geometrical aspects of the models are also discussed.

LRS Bianchi Type-II modified holographic Ricci dark energy models in a scalar-tensor theory of gravitation

A locally rotationally symmetric (LRS) Bianchi type-II spacetime is considered in the presence of dark matter and anisotropic modified holographic Ricci dark energy in the scalar-tensor theory of Saez and Ballester (Phys. Lett. A 113: 467, 1986). To obtain exact solutions of Saez-Ballester gravitational field equations we use the following physically significant conditions: (i) the scalar expansion of the space time is proportional to its shear scalar, (ii) hybrid expansion law for the scale factor proposed by Akarsu et al. (JCAP 01: 022, 2014) and (iii) modified Ricci dark energy density given by Chen and Jing (Phys. Lett. B 679: 144, 2009). The solution describes modified holographic Ricci dark energy models, in this theory, which exhibit a smooth transition from decelerated phase to the present accelerated phase of the universe. This result is in accordance with the present day observations of cosmology. The dynamical parameters of the models are computed and their physical importance, in cosmology, is discussed.

A modified holographic Ricci dark energy model in a self-creation cosmology

This paper deals with a locally rotationally symmetric Bianchi type II space–time with dark matter and anisotropic modified holographic Ricci dark energy as source in second self-creation theory of gravitation proposed by Barber (Gen. Relativ. Gravit. 14, 117 (1982)). To solve the field equations of this theory we have used (i) hybrid expansion law, (ii) a relation between metric potentials and a modified holographic Ricci dark energy given by Chen and Jing (Phys. Lett. B, 679, 144 (2009)). The solution obtained represents a Bianchi type II modified holographic dark energy model in self-creation cosmology. We observe that there is a smooth transition of the universe from decelerated phase to accelerated phase. This fact is in good agreement with the observations of modern cosmology. We have also discussed some important physical aspects of the model.

Viscous extended holographic Ricci dark energy in the framework of standard Eckart theory

In this paper, we report a study on the viscous extended holographic Ricci dark energy (EHRDE) model under the assumption of existence of bulk viscosity in the linear barotropic fluid and the EHRDE in the framework of standard Eckart theory of relativistic irreversible thermodynamics and it has been observed that the non-equilibrium bulk viscous pressure is significantly smaller than the local equilibrium pressure. We have studied the equation of state (EoS) parameter and observed that the EoS behaves like “quintom” and is consistent with the constraints set by observational data sets from SNLS3, BAO and Planck + WMAP9 + WiggleZ measurements in [S. Kumar and L. Xu, Phys. Lett. B 737, 244 (2014)]. Analysis of statefinder parameters has shown the possibility of attainment of Lambda cold dark matter ([Formula: see text]CDM) phase under current model and at the same time it has been pointed out that the redshift z = 0, i.e. the current universe, the statefinder pair is different from that of [Formula: see text]CDM and the [Formula: see text]CDM can be attained in a later stage of the universe. An analysis of stability has shown that although the viscous EHRDE along with viscous barotropic is classically unstable in the present epoch, it can lead to a stable universe in very late stage. Considering an universe enveloped by event horizon, we have observed validity of generalized second law (GSL) of thermodynamics.

Instability in interacting dark sector: an appropriate holographic Ricci dark energy model

In this paper we investigate the consequences of phantom crossing considering the perturbative dynamics in models with interaction in their dark sector. By mean of a general study of gauge-invariant variables in comoving gauge, we relate the sources of instabilities in the structure formation process with the phantom crossing. In order to illustrate these relations and its consequences in more detail, we consider a specific case of an holographic dark energy interacting with dark matter. We find that in spite of the model is in excellent agreement with observational data at background level, however it is plagued of instabilities in its perturbative dynamics. We reconstruct the model in order to avoid these undesirable instabilities, and we show that this implies a modification of the concordance model at background. Also we find drastic changes on the parameters space in our model when instabilities are avoided.