Narrow Results

Recently, the tachyon cosmology has been represented as dark energy model to support the current acceleration of the universe without phantom crossing. In this paper, we study the dynamics of the tachyon cosmology in which the field plays the role of tachyon field and also non-minimally coupled to the matter Lagrangian. The model shows current universe acceleration and also phantom crossing in the future. Two cosmological tests are also performed to validate the model; the difference in the distance modulus and the model independent Cosmological Redshift Drift (CRD) test.

In this paper, we investigate the Sharma–Mittal holographic dark energy (SMHDE) model in the context of a spatially homogeneous and isotropic flat Friedmann–Robertson–Walker (FRW) Universe by taking various values of model parameters $R$ and $\delta$ and the Hubble horizon is taken as the infrared cut-off. We have analyzed the deceleration parameter $(q)$ and the EoS parameter. According to the deceleration parameter, the Universe is in an accelerating and expanding phase, which is compatible with the observational data. The EoS parameter depicts that presently the Universe is lying in the quintessence region and at a late time it will show $\mathrm{\Lambda }$CDM behavior. It is also concluded by the stability analysis that SMHDE model is classically stable at present and future. To understand the dynamics of our Universe, we have established a correspondence among SMHDE and the quintessence, tachyon and K-essence scalar-field models. Our results show that the Universe is in an accelerating expansion mode described by quintessence like behavior. We go further and estimate the model parameters by using the distance modulus measurement of the recent Union 2.1 dataset of supernovae.

In this study, the Kaniadakis holographic dark energy (KHDE) model is investigated within the framework of a flat FLRW universe by using an infrared cut-off as Hubble horizon. For the different values of the Kaniadakis parameter $\kappa$ and $C^2$, we perform an analysis on the deceleration, the equation of state and the energy density parameters. The current phase shift of the Cosmos may be rationalized by the change in sign of the deceleration parameter in the KHDE model, which went from $+ve$ to $-ve$, signifying a move from a phase of deceleration to one of acceleration. In order to get an understanding of the geometrical behavior shown by the KHDE model, we compute and show the statefinder evolutionary trajectory for the pairs $(r,s)$ and $(q,r)$. The evolutionary trajectory of ${\omega }_D-{\omega }_D^{\prime }$ reveals that the ${\omega }_D$ crosses the phantom divide line ${\omega }_D=-1$ at a late period in the evolutionary process. It has also been determined, by examination of the KHDE models stability analysis, that the model has behaved in an unstable manner during the whole course of the history of the universe. In addition to this, we optimized the model parameters by making use of the distance modulus measurement that was taken from the most current Union 2.1 dataset of supernovae.