Umesh Kumar Sharma

To inspect the nature of dark energy, we developed a new dark energy model that we thoroughly examine in this paper. The main components of our study are non-extensive new agegraphic dark energy through Kaniadakis entropy and an infrared cutoff as a conformal time. The proposed model uses the Kaniadakis parameter [ ] to quantify the deviation from the new agegraphic dark energy model. We further evaluate the evolution of a universe filled with pressure-less matter and the dark energy candidates that result, and the cosmological properties of the proposed dark energy model. Both non-interaction and interaction between the two sectors will be taken into account. Expressions are derived for both the deceleration and the equation of state parameters, as well as the differential equation for the dark energy density parameter. The model exhibits complete quintessence behavior in the non-interaction and interaction scenario. We examined the model’s stability in both scenarios through the squared sound speed. We constrain our model parameters using the recent observational data sets Pantheon+SH0ES which are having 1701 data points.

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 [ ]. 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.

The Barrow’s Holographic Dark Energy (BHDE) Model is proposed in an axially symmetric anisotropic spacetime which is employing Hubble horizon as an infrared cutoff (IR cutoff). The transition of the universe from a matter dominated era to a dark energy dominated era is investigated in this model. Furthermore, the Equation of State (EoS) parameter explains how the universe evolves with non-extensive term or Barrow parameter [ ] for both phase (i) phantom era ([ ]) and (ii) quintessence era ([ ]). In order to reconcile the dark energy, the reconstruction of scalar field potential is considered. Some of the physical properties of the model are also described.

This paper considers the only sectors to constitute the present universe as the dark matter and dark energy. The proposed new agegraphic dark energy model studies the gradual transition from matter to dark energy in sequential order, including the current dominance of the matter sector by dark energy. The model utilizes concepts of Tsallis entropy and the Karolyhazy relation with conformal time [ ] as the time scale. Various evolutionary aspects of the universe are characterized by Tsallis parameter [ ] and the model constant [ ]. Expressions for dynamic behavior of dark energy, as a differential equation, equation of state and deceleration parameters are obtained to describe the thermal history of universe evolution. Also, the stability of the model is analyzed through squared sound speed parameter. The analysis is made by considering an interaction as well as independence among the constituent sectors of the universe.

This study focuses on the cosmological evolution of Barrow holographic dark energy (BHDE) in a flat FLRW-universe. We take into account a time-dependent scale factor [ ], where k and n are positive values, to find the solutions to field equations. This scale factor results in a smooth transition of the universe from its previous decelerating stage to its most recent accelerating stage. Using the Granda–Oliveros cut-off, we examine the chronology of the deceleration parameter, equation of state parameter, and density parameter, and we analyze the positive aspects of the BHDE model. Negative pressure values in this model suggest dark energy dominance, resulting in the universe’s acceleration. We use the statefinder parameters ([ ]) to improve the accuracy of the results of the dark energy model that is similar to the [ ]-CDM model.

In statistical theory, the Tsallis entropy is an extended form of the Boltzmann–Gibbs entropy. The dimensionless parameter [ ] 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 [ ], 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[ ] SNIa [ ] union 2.1 sources are used to evaluate the model’s effectiveness.

This paper explores the quintessence reconstruction and statefinder perspective of Kaniadakis holographic dark energy model in a flat universe with future event horizon as an IR-cutoff. The cosmological parameters of this model were re-examined from the quintessence behavior aspect. Also we reconstruct, [ ], the potential of quintessence scalar field, which shows the best fit with joint analysis data of JLA+CC+BAO for the priors [ ], [ ]. In the [ ]–[ ] phase space, the freezing-tracker model represents our canonical scalar field. This model exhibits quintessence behavior in the statefinder ([ ]–[ ]) plane for model parameters [ ] and [ ] that are close to [ ] and [ ]. The present values of deceleration [ ], statefinder [ ], jerk [ ] and model parameters [ ] are consistent with the limits of the observational data. Using the distance modulus [ ], we also fit 580 SN Type I Union2.1 data sets to our model.