Tsallis Holographic Dark Energy Model Research Articles

Tsallis Holographic Dark Energy with Power Law Ansatz Approach

Holographic principles have proven to be a very interesting approach towards dealing with the issues of the late-time acceleration of the universe, which has resulted in a great amount of work on holographic dark energy models. We consider one such very interesting holographic scenario, namely the Tsallis Holographic dark energy model, and consider an ansatz based approach to such models. We consider three cosmological scenarios in such models, namely those with viscous, non-viscous, and Chaplygin gas scenarios, discussing various crucial aspects related to these models. We discuss various crucial properties of the Tsallis model in such scenarios and see how the phantom divide is crossed in each case, but it is only the Chaplygin gas models which provide a better view on stability issues.The symmetry property of the theory presented in the article is the assumption that space is isotropic. Using bulk viscosity instead of shear viscosity reflects spatial isotropy.

Bianchi Tip-V Evreninde Granda-Oliveros Ölçekli Tsallis Holografik Karanlık Enerji

A wide variety of cosmological observations show us that our universe is in an accelerated expansion phase. Dark Energy and Dark Matter are thought to be two of the causes of this accelerated expansion. Therefore, scientists have recently been doing many studies on dark energy and matter. In particular, many energy density relations are written, and research is done about space-time structure. In this sense, the Tsallis holographic dark energy model is also in a current and interesting position. The study establishes a relationship between the Tsallis holographic dark energy (THDE) model and some scalar fields (quintessence, tachyon, dilaton scalar fields, etc.) specific to the Bianchi-type V space-time model. The relationship above is discussed within the Granda-Oliveros (GO) cut-off framework. The state equation parameter is calculated analytically, and the phase of our universe for this model is investigated with the graphs drawn. In addition, there is how the kinetic energy and the scalar potential change with time. The results are again analyzed numerically with graphs.

Bianchi type-III THDE quintessence model with hybrid scale factor

The current research investigates the behavior of the Tsallis holographic dark energy (THDE) model with quintessence in a homogeneous and anisotropic Bianchi type-III space–time. We construct the model by using two conditions: ( i) expansion scalar ( θ) is proportionate to shear scalar ( σ) in the model and ( ii) hybrid scale factor a = t βe γt, where β > 0 and γ > 0 are constants. Our study is based on Type Ia supernovae data in combination with CMB and BAO observations (Giostri et al., JCAP 3, 27); the present values of Hubble constant and deceleration parameter are H0 = 73.8 and q0 = −0.54, respectively. Compiling our theoretical models with these data, we obtain [Formula: see text] for [Formula: see text], respectively. We completed an entirely novel form of cosmic model where the expansion occurs during the present accelerated phase for the constraints. We have discussed the conformity among the scalar field model of quintessence and THDE model. To understand the Universe, we have also established the relations for distance modulus, luminosity distance, and angular-diameter distance. Some geometric and physical aspects of the THDE model are also highlighted.

Bianchi Type-V space time with Tsallis holographic dark energy

In this paper, using the framework of Saez–Ballester theory, Bianchi Type-V metric Tsallis holographic dark energy models with interacting and non-interacting elements have been constructed. To obtain solutions for the model, we used correlation between metric potentials and varying deceleration parameters. There is additional discussion of the models’ physical characteristics and behavior.

Quintessence reconstruction through new Tsallis holographic dark energy model

In statistical theory, the Tsallis entropy is an extended form of the Boltzmann–Gibbs entropy. The dimensionless parameter [Formula: see text] is employed to state the quantitative difference from the standard scenario. The concepts of Tsallis entropy and the future event horizon are employed in formulating the present new Tsallis holographic dark energy (NTHDE) model. The model attempts to explain the properties of dark energy using the foundation of quantum gravity. The differential equation characterizing the evolution of the NTHDE density parameter is obtained. Expressions stating the dynamic behavior such as equation of state (EoS), deceleration and jerk parameters are obtained in terms of the NTHDE density parameter. For [Formula: see text], the quintessence nature of scalar field could completely characterize the NTHDE. A reconstruction of the scalar field’s dynamics and quintessence potential is attempted. We demonstrate that the diagnosis made by statefinder is adaptive enough to distinguish between quintessence and cosmological constant-based dark energy models. Additionally, observational data obtained from CC[Formula: see text] SNIa [Formula: see text] union 2.1 sources are used to evaluate the model’s effectiveness.

Diagnosing Renyi and Tsallis holographic dark energy models with Hubble’s horizon cutoff

Diagnosing Renyi and Tsallis holographic dark energy models with Hubble’s horizon cutoff

Dynamical analysis of the Tsallis holographic dark energy models with event horizon as cut-off and interaction with matter

The model of generalized Tsallis holographic dark energy (which is known to be particular representative of Nojiri–Odintsov HDE) with event horizon as cut-off is investigated using methods of dynamical analysis. We take into consideration possible interaction with dark energy and matter in various forms. Critical points are determined. Cosmological evolution of the universe depends from interaction parameters. If we use event horizon scale as cut-off quasi-de Sitter expansion is possible only for interaction of type [Formula: see text] (where [Formula: see text] is the Hubble parameter). For interactions [Formula: see text] and [Formula: see text] universe eventually stops ([Formula: see text]) or ends its existence in final singularity ([Formula: see text]). In the first case, fraction of dark energy tends to [Formula: see text] or constant value lesser than 1 because dynamical equilibrium between matter and dark energy is established on late times.

Tsallis holographic dark energy under complex form of quintessence model

In this paper, we use a Tsallis holographic dark energy model in two forms, interacting and non-interacting cases, to acquire some parameters as the equation of state for the energy density of the Tsallis model in the FRW Universe concerning the complex form of quintessence model. We will study the cosmology of complex quintessence by revamping the potential and investigating the scalar field dynamics. Then we analyze () and stability in two cases, i.e. non-interacting and interacting. We will explore whether these cases describe a real Universe by calculating fractional energy density Ω D and concerning two parts of the quintessence field effect (complex and real part ) by considering the real part of this field to be a slow-roll field. We know that the part in which the fractional energy density (Ω D > 1) does not describe a real Universe. Also, we specified an interacting coupling parameter b 2 that depends on the constant parameter of the Tsallis holographic model (δ) with respect to fractional energy density (0.73). Unlike independence between the fractional energy density and interacting coupling in the real quintessence model, we determine a relationship among these parameters in this theory. Finally, by plotting some figures, we specify the features of () and () in two cases and compare the result with each other.

Statefinder diagnosis of Tsallis holographic dark energy model in f(R, T) Theory

In this study, Tsallis Holographic Dark Energy (THDE) was studied in the framework of f(R, T) gravitational theory by taking into consideration the homogeneous and anisotropic Bianchi-I spacetime. The Hubble horizon was chosen as IR cutoff of the system. To obtain solutions of field equations, THDE density and a form of Hubble parameter were used. Additionally, various physical parameters such as energy of state parameter, deceleration parameter and scale factor have been discussed. The characteristics and parameters of the model have been also examined by plotting their evolution graphics for redshift z. Furthermore, statefinder parameters, which are effective tools for separating dark energy models, have been explored. By the illustration of trajectory in r − s plane, it is found that this model behaves like Chaplygin gas at initial stage, then ranging in quintessence region it finally approaches to Λ Cold Dark Matter. Lastly, from the evolutions of r − q and s − q planes it is seen that the model evolves to the De Sitter expansion point.

Tsallis holographic dark energy model with event horizon cutoff in modified gravity

In this paper, we considered the Tsallis holographic dark energy model in frames of Nojiri–Odintsov gravity with [Formula: see text]. For IR, cutoff event horizon is taken. The cosmological evolution of such universe is investigated for various initial conditions and values of parameters. The dependence of the Hubble parameter [Formula: see text] from time in the future has an oscillation. It is shown that for [Formula: see text] appearance of singularities are typical and the time up to these singularities can be relatively small from cosmological viewpoint. The singularity is associated with the zero of second derivative of [Formula: see text] on [Formula: see text]. It is interesting to note that these models can describe observational data from Ia supernovae astrophysics and dependence of the Hubble parameter from redshift [Formula: see text] at least not worse than canonical [Formula: see text]CDM model.

Bianchi Type V Tsallis Holographic Dark Energy Model with Hybrid Expansion Law

A number of recent cosmological observations have provided increasing evidence that currently the universe is undergoing a phase of accelerated expansion, the root cause of which is supposed to be due to an exotic component of the universe with large negative pressure, dubbed dark energy. Out of the various candidates of dark energy proposed in the literature, the holographic dark energy emerged from the Holographic Principle is drawing much attention in the research field. In this paper, we investigate a spatially homogeneous and anisotropic Bianchi Type V space-time filled with non-interacting Tsallis holographic dark energy (THDE) with Hubble horizon as the IR cutoff and pressureless cold dark matter within the framework of General Relativity. Exact solutions of the Einstein field equations are obtained by considering the average scale factor to be a combination of a power law and an exponential law, the so called hybrid expansion law first proposed by Akarsu et al. (2014). We study the cosmological dynamics of various models for different values of the non-additive parameter that appeared in the Tsallis entropy and that for that appeared in the exponential function of the hybrid expansion law. We find that our model exhibits present cosmological scenario.

Marder space-time with Tsallis holographic dark energy

This present communication is an outcome of the investigation on newly proposed holographic dark energy model such as the Tsallis holographic dark energy (THDE) with Hubble horizon cutoff regarded as IR cutoff (infrared cutoff) for a spatially homogeneous and anisotropic Marder space-time in the framework of general relativity theory (GRT). Here, we have constructed the THDE models with Hubble horizon cutoff in three different ways, based on the following possibilities: (i) a varying deceleration parameter proposed by Mishra et al., (ii) hybrid expansion law (HEL) proposed by Akarsu et al. and (iii) a linearly varying deceleration parameter (LVDP) given by Akarsu and Dereli. The rapid expansion of the cosmos is thus justified for obtained models through the deceleration parameter (DP). In this way, the equation of state (EoS) parameter ([Formula: see text]) of the models describe the phantom and quintessence phases of the cosmos. Also, we compare the cosmological parameters of the obtained models with the parameters of [Formula: see text]CDM model, which indicates that the models-I and II are nearly identical to the [Formula: see text]CDM model.

Thermodynamics and stability analysis of Tsallis Holographic Dark Energy (THDE) models in [formula omitted] gravity

In this manuscript, we develop the counterpart of Tsallis holographic dark energy (THDE) model in F(R,T) theory (where R represents Ricci scalar and T is trace of energy momentum tensor (EMT)) using the two IR-cutoffs namely Hubble horizon (HH) and Granda-Oliveros (GO). The THDE is proposed on the basis of Tsallis entropy (Tsallis and Cirto, 2013) and the holographic hypothesis (Tavayef, 2018). Cosmic evolution is analyzed using the equation of state (EOS) parameter which results in both quintessence and phantom regimes. The stability analysis of reconstructed models is also made with the help of squared speed of sound. Moreover, we study the thermodynamic picture and developed constraints for the validity of generalized second law of thermodynamics (GSLT). It is remarked that these reconstructed models can be useful to further explore the cosmic issues.

Crossing of Phantom Divide Line in Model of Interacting Tsallis Holographic Dark Energy

We consider a Tsallis holographic dark energy model with interaction between dark energy and matter. The density of dark energy is taken as ρd∼3C2/L4−2γ, where C, γ are constants. The event horizon is chosen as the characteristic scale L. The cosmological dynamics of the universe are analyzed, with special attention paid to the possibility of crossing the phantom line weff=−1. It is shown that for certain values of parameters this may occur not only once, but also twice.

New Tsallis holographic dark energy

Tsallis entropy is a generalization of the Boltzmann–Gibbs entropy in statistical theory which uses a parameter delta to measure the deviation from the standard scenario quantitatively. Using concepts of Tsallis entropy and future event horizon, we construct a new Tsallis holographic dark energy model. The parameters c and delta will be used to characterize various aspects of the model. Analytical expressions for various cosmological parameters such as the differential equation describing the evolution of the effective dark energy density parameter, the equation of state parameter and the deceleration parameter are obtained. The equation of state parameter for the current model exhibits the pure quintessence behaviour for c>1, quintom behaviour for c<1 whereas the Lambda CDM model is recovered for c=1. To analyze the thermal history of the universe, we obtained the expression for the deceleration parameter and found that for z approx 0.6, the phase transits from deceleration to acceleration.

Interacting Tsallis holographic dark energy and tachyon scalar field dark energy model in Bianchi type-II Universe

In this work, we study the interaction between the dark matter (DM) component and the dark energy (DE) component using the Tsallis holographic dark energy (THDE) density expression for a Bianchi type-II space–time within the framework of general relativity (GR). To obtain the exact solutions of Einstein’s field equations, we use two constraints: (i) the expansion scalar [Formula: see text] of the Universe is proportional to the component [Formula: see text] of the shear tensor [Formula: see text], i.e. [Formula: see text] and (ii) we assume that the scale factor follows the Hybrid Expansion Law (HEL). We have discussed some geometrical and physical parameters of our model such as the deceleration parameter (DP) and the equation of state (EoS) parameter. In these parameters, we plot their behavior in terms of redshift [Formula: see text]. We observe that the DP evolves from the early decelerating phase to the current accelerating phase with a current value consistent with the observation data. The EoS parameter evolves from a state of a stiff-matter fluid-dominated era [Formula: see text] for high redshift [Formula: see text] to a [Formula: see text]CDM era [Formula: see text] in the later times. Also, we have established a correspondence between the THDE model and the tachyon scalar field dark energy model. We have reconstructed the potential and the tachyon scalar field, which describes the current accelerated expansion of the Universe. Finally, using 51 values of observed Hubble measurement and the technique [Formula: see text]-test, we found the best fit value for the model parameters [Formula: see text], [Formula: see text] and [Formula: see text] (current value of the Hubble parameter). These results are consistent with the new measurements of [Formula: see text].37

Kantowski\u2013Sachs Tsallis holographic dark energy model with sign-changeable interaction

In this work devoted to the investigation of the Tsallis holographic dark energy (IR cut-off is Hubble radius) in homogeneous and anisotropic Kantowski–Sachs Universe within the frame-work of Saez–Ballester scalar tensor theory of gravitation. We have constructed non-interacting and interacting Tsallis holographic dark energy models by solving the field equations using the relationship between the metric potentials. This relation leads to a viable deceleration parameter model which exhibits a transition of the Universe from deceleration to acceleration. In interacting case, we focus on sign-changeable interaction between Tsallis holographic dark energy and dark matter. The dynamical parameters like equation of state parameter, energy densities of Tsallis holographic dark energy and dark matter, deceleration parameter, and statefinder parameters of the models are explained through graphical representation. And also, we discussed the stability analysis of the our models.

Reconstructing Tsallis holographic quintessence

Within the framework of quantum gravity and modified entropy-area formalism, the Tsallis holographic dark energy is an effort to peep into a mysterious content of the Universe, the dark energy, to analyze its nature. The Tsallis parameter [Formula: see text] provides the main characteristic of the Tsallis holographic dark energy. Opting the value of Tsallis parameter [Formula: see text], a quintessence scalar field description of the Tsallis holographic dark energy model can be obtained. In this work, we present this quintessential explanation of the Tsallis holographic dark energy with [Formula: see text] and reconstruct the dynamics of the scalar field and the potential of quintessence.

Tsallis holographic dark energy models in Bianchi type space time

The main purpose of this paper is to construct interacting and non-interacting Tsallis holographic dark energy models in an anisotropic and homogeneous Bianchi type-VI0 space time within the framework of a scalar tensor theory proposed by Saez and Ballester (1986). For this purpose, we use the relationship between metric potentials of the model and varying deceleration parameter to solve the Saez–Ballester field equations. In order to study the physical behavior of the models, we obtain some well-known cosmological parameters like deceleration, equation of state, statefinder, Om diagnostic parameters, and ωT - ωT′ planes of the models. Also, we observe that in our non-interacting and interacting models deceleration and equation of state parameters support the recent observational data.

Tsallis holographic dark energy model with observational constraints in the higher derivative theory of gravity

The present study deals with a Tsallis holographic dark energy model in a flat Friedmann-Lamatire-Rbertson-Walker space-time geometry in the context of higher derivative theory of gravity. We have solved the field equations by applying energy conservation-law in non-interacting case and have obtained such a scale factor a(τ)=[sinh(2a1τ)]12 where a1 is called as model parameter which shows transit phase evolution of the universe (decelerating to accelerating). Using this scale factor we have obtained the various cosmological parameters viz. Hubble parameter H, deceleration parameter (DP) q, jerk j, snap s, lerk l and max-out m. Constraining on Hubble parameters H(z) by the observational data of H(z) we have obtained the present values of H0, a0 and a1 and by using these constrained values, we have studied other cosmological parameters. Taking the constant equation of state (EoS) ωm for ordinary matter, we have investigated the effective behaviour of various cosmological parameters and energy conditions in our model. We have observed the present values of {t0,H0,q0,j0,s0,l0,m0,ωde0,ω0(eff)} and discussed with ΛCDM model. We have found the age of the present universe t0=13.05 Gyrs, present value of DP q0=−0.8065 and transition point zt=0.748 which are compatible with several observational results.