Tsallis Holographic Dark Energy Research Articles

New Tsallis holographic dark energy with Granda–Oliveros as IR-cutoff

In the current study, a theoretical model for non-interacting new Tsallis holographic dark energy is constructed using the Granda–Oliveros as the IR cutoff with specified scale factor [Formula: see text]. The time-dependent deceleration parameter, with appropriate assumptions, yields this scale factor. The features of the deceleration parameter, equation of state parameter, density parameter, and jerk parameter are then investigated for this model. According to our findings, the cosmos has a normal thermal history, dark matter and dark energy eras occurring one after the other until dark energy eventually takes over entirely in the far future. Additionally, the evolution of the potential and pressure to indicate the universe’s accelerated expansion by using our model are studied. We investigate the evolution trajectory of statefinder parameters, which is consistent with ΛCDM model.

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.

Formula omitted]-phase space analysis of interacting Tsallis holographic dark energy in [formula omitted] gravity

In the present analysis the cosmological evolution of an interacting scenario between Tsallis holographic dark energy (THDE) and pressure less dark matter with Hubble’s scale as IR cutoff of the universe in flat FRW space–time within the framework of f(Q) gravity is analyzed. Also, governed the features of the f(Q) gravity model using some cosmological parameters like energy density, deceleration parameter, equation of state parameter (EoSP), squared speed of sound, (r−s) plane and (ωT−ωT′) plane in view of the bounce form of scale factor (which include power and de-Sitter cosmology) for three different values of positive non-additively parameter η. In the analysis the evaluated THDE EoSP for three different values of positive non-additively parameter represents, the Universe evolve from matter dominated epoch to ΛCDM model where ωT=−1 through the quintessence region in which ωT>−1 and remain existing in ΛCDM. Some other cosmological parameter are discussed in details.

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.

Interacting New Tsallis holographic dark energy

We constructed the evolution of a flat FRW universe filled with New Tsallis holographic dark energy (NTHDE) and matter (dust) that interact with each other via a wellknown source term. Assuming the hubble horizon IR cutoff length, extracted the governing equation for the NTHDE density parameter’s evolution and solved it numerically to find the evolution of other relevant cosmological parameters, e.g., equation of state and deceleration parameters. We then repeated same findings when the radiation component was included. According to our findings, the cosmos has a normal thermal history, with radiation, dark matter (DM) and dark energy (DE) eras occurring one after the other until dark energy eventually takes over entirely in the far future. We also found that according to the values of the parameters (δ, b12, b22), the NTHDE equation of state parameter can be either quintessence like or phantom like or very close to cosmological constant during the cosmic evolution. This fascinating feature of the scenario is achieved without the use of an explicit cosmological constant term, and it arises purely from modified cosmology through an interacting NTHDE with varying δ. Finally, the hubble parameter’s evolution is examined and contrasted with the most recent hubble parameter results.

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.

Tsallis Holographic Dark Energy in Bianchi Type I Universe in the Framework of $$\boldsymbol{f(R)}$$ Theory of Gravity

Tsallis Holographic Dark Energy in Bianchi Type I Universe in the Framework of $$\boldsymbol{f(R)}$$ Theory of Gravity

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.

Hyperbolic Scenario of Accelerating Universe in Modified Gravity

Throughout this study, locally rotationally symmetric (LRS) Bianchi type-V space-time is pondered with Tsallis holographic dark energy (THDE) with the Granda–Oliveros (GO) cut-off in the Sáez–Ballester (SB) theory of gravity. A parameterization of the deceleration parameter (q) has been suggested: q=α−βH2. The proposed deceleration parameterization demonstrates the Universe’s phase transition from early deceleration to current acceleration. Markov chain Monte Carlo (MCMC) was utilized to have the best-fit value for our model parameter and confirm that the model satisfies the recent observational data. Additional parameters such as deceleration parameter q with cosmographic parameters jerk, snap, and lerk have also been observed physically and graphically. The constructed model is differentiated from other dark energy models using statefinder pair analysis. Some important features of the model are discussed physically and geometrically.

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.

New Tsallis holographic dark energy with apparent horizon as IR-cutoff in non-flat Universe

In this work, new Tsallis holographic dark energy with apparent horizon as IR-cutoff is constructed in a non-flat Friedmann–Lemaitre–Robertson–Walker Universe. The accelerating expansion phase of the Universe is described by using deceleration parameter, equation of state parameter and density parameter by using different values of new Tsallis holographic dark energy (NTHDE) parameter “[Formula: see text]”. The NTHDE Universe’s transition from a decelerated to an accelerated expanding phase is described by the smooth graph of deceleration parameter. Depending on distinct values of Tsallis parameter “[Formula: see text]”, we have explored the quintessence behavior of the equation of state parameter. We used Hubble data sets obtained using Cosmic Chronometric methods and distance modulus measurement of Type Ia Supernova to fit the NTHDE parameters. Stability of our model by analyzing the squared speed of sound is investigated as well.

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.

Observational constraints on Tsallis holographic dark energy with Ricci horizon cutoff

In this research, we are interested in constraining the nonlinear interacting and noninteracting Tsallis holographic dark energy (THDE) with Ricci horizon cutoff by employing three observational datasets. To this aim, the THDE with Ricci horizon considering the noninteraction and nonlinear interaction terms will be fitted by the SNe Ia, SNe Ia+H(z), and SNe Ia+H(z)+GRB samples to investigate the Hubble ($H(z)$), dark energy equation of state ($\omega_{DE}$), effective equation of state ($\omega_{eff}$), and deceleration ($q$) parameters. Investigating the $H(z)$ parameter illustrates that our models are in good consistent with respect to observation. Also, it can reveal the turning point for both noninteracting and nonlinear interacting THDE with Ricci cutoff in the late time era. Next, the analysis of the $\omega_{DE}$ for our models displays that the dark energy can experience the phantom state at the current time. However, it lies in the quintessence regime in the early era and approaches the cosmological constant in the late-time epoch. Similar results will be for the $\omega_{eff}$ parameter with this difference that the $\omega_{eff}$ will experience the quintessence region at the current redshift. Next to the mentioned parameters, the study of the $q$ parameter indicates that the models satisfy an acceptable transition phase from the matter to the dark energy-dominated era. After that, the classical stability ($v_{s}^{2}$) will be analyzed for our models. The $v_{s}^{2}$ shows that the noninteracting and nonlinear interacting THDE with Ricci cutoff will be stable in the past era, unstable in the present, and progressive epochs. Then, we will employ the $Jerk$ ($J$) and $OM$ parameters to distinguish between our models and the $\Lambda CDM$ model. Finally, we will calculate the age of the Universe for the THDE and nonlinear interacting THDE with Ricci as the IR cutoff.

Tsallis holographic dark energy scenario in viscous f(Q) gravity with tachyon field

This study investigates a bulk viscous fluid anisotropic cosmological model with [Formula: see text] gravity. Here, [Formula: see text] stands for the nonmetricity factor that drives gravitational interaction. We reconstructed the associated parameters with Tsallis holographic dark energy (THDE). We have solved the modified Einstein’s field equations by considering the bulk viscosity factor [Formula: see text]. Under the viscous and nonviscous THDE frameworks, we have obtained the expressions of [Formula: see text] using the power-law form of expansion. We have investigated the nature of various energy conditions for the stability analysis. The positive behavior of DEC and WEC indicates the model’s validation; on the other hand, SEC is violating, indicating the universe’s accelerated expansion. We have also investigated the reconstructed EoS parameter [Formula: see text] for bulk viscosity and obtained the one that lies in both quintessence and phantom regions. We also discussed the correspondence of the tachyon scalar field with THDE energy density in [Formula: see text] gravity. This correspondence permits the reconstruction of potentials and dynamics for scalar field models describing accelerated expansion.

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.

New Tsallis holographic dark energy with future event horizon as IR-cutoff in non-flat Universe

In this work, new Tsallis holographic dark energy (NTHDE) with future event horizon as IR-cutoff is constructed in a non-flat Friedmann–Lemaitre–Robertson–Walker Universe. The accelerating expansion phase of the universe is described by using deceleration parameter, equation of state parameter and density parameter by using different values of NTHDE parameter “[Formula: see text]” and “[Formula: see text]”. We specifically derive the differential equations for the dark-energy density parameter (DP) and hence the equation of state parameter (EoS) by taking into account closed and open spatial geometry. In both a closed and an open universe, the equation of state parameter exhibits pure quintessence behavior for [Formula: see text], quintom behavior for [Formula: see text], and [Formula: see text]CDM model recovery for [Formula: see text]. We can see the phase changes from deceleration to acceleration at [Formula: see text] by tracking the evolution of the deceleration parameter. As inferred from the evolution of the Hubble parameter, NTHDE in a non-flat universe precisely matches Hubble data. Stability of our model by analyzing the squared speed of sound is investigated as well.

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.