Ghost dark energy in Rastall theory

Making use of the generalized form of the Ghost dark energy density, which has the functional form [Formula: see text] where [Formula: see text] represents the Hubble expanding rate, the present accelerated enlargement behavior of the cosmos is investigated from the Rastall theory perspective. After finding a relation for the Hubble cosmic expansion rate, we consider recent cosmology-independent measurements calculated for the expansion history of the cosmos to fit the model via the [Formula: see text]-analysis. Moreover, we discuss the cosmographic properties of the model with the help of some cosmological quantities. We show that our model is stable and consistent with the recent astrophysical data. Also, for our model, we investigate cosmological interpretations of thermodynamics.

Cosmic evolution of ghost dark energy models in f(G,T) gravity

The aim of this paper is to study the reconstruction paradigm for both ghost as well as generalized ghost dark energy models in the context of [Formula: see text] gravity. To accomplish this, we use correspondence scenario for pressureless flat FRW universe with power-law scale factor. The cosmological behavior of reconstructed models is analyzed through graphical analysis of deceleration, equation of state, squared speed of sound parameters and phase planes. It is found that the deceleration parameter represents accelerated epoch for both models whereas equation of state parameter indicates phantom era of the universe for ghost dark energy model and quintessence for its generalized version. The phase planes [Formula: see text] and [Formula: see text] indicate the freezing region with phantom phase for both reconstructed dark energy models. We conclude that the squared speed of sound parameter leads to the stability of generalized ghost dark energy model only.

Generalized ghost dark energy in DGP model

In 2000, Dvali et al. [4-D gravity on a brane in 5-D Minkowski space, Phys. Lett. B 485 (2000) 208–214] proposed a new braneworld model named as DGP model, having two branches with [Formula: see text]. Former one [Formula: see text] known as accelerating branch, which explains accelerating phase of the Universe without adding cosmological constant or Dark energy (DE), whereas later one [Formula: see text] represents the decelerating branch. Here, we have investigated the behavior of Generalized Ghost Dark Energy (GGDE) under the decelerating branch of DGP model. We have studied the importance of GGDE model to explain the current phase of the Universe. To check the validity of the present model, we study the behavior of different cosmological parameters such as Hubble parameter, equation of state (EoS) parameter and deceleration parameter with respect to scale factor. Then, we have analyzed the [Formula: see text] to confirm no freezing region of this study and point out thawing region. Furthermore, we have checked the gradient of stability by calculating the squared sound speed. Then, we extend our study to check the viability of this model under investigation through the analysis of statefinder diagnosis parameters for the present cosmological setup.

Viability of specific reconstructed f(T,𝒯 ) models

The reconstruction scenario of well-established dark energy models such as pilgrim dark energy model and generalized ghost dark energy with Hubble horizon and [Formula: see text] models is being considered. We have established [Formula: see text] models and analyzed their viability through equation of state parameter and [Formula: see text] (where prime denotes derivative with respect to [Formula: see text]) plane. The equation of state parameter evolutes the universe in three different phases such as quintessence, vacuum and phantom. However, the [Formula: see text] plane also describes the thawing as well as freezing region of the universe. The recent observational data also favor our results.