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J. Jena

Publications and source records attributed to J. Jena.

3 recordsLinked to original sources

The cosmological model in $ f(R,T^ϕ) $ gravity with Scalar Field conformity

The homogeneous and isotropic cosmological model in generalized $ f(R,T^ϕ) $ theories associated with scalar field is discussed, which is motivated by the $ f(R,T) $ theory of gravity studied by Harko et al. \cite{Harko:2011kv, Harko:2014pqa}. The $ f(R,T^ϕ) $ gravity can be explained as $ f(R,T) $ gravity with a self-interacting scalar field $ ϕ$, where $ T^ϕ$ is the trace of the energy-momentum tensor. The parametrization of Hubble parameter $ H(t) $ is taken as $ α-βe^{-γt} $, where $ α$, $β$ and $γ$ are arbitrary constants such that $ α, γ>0 $ and $ β<0 $. The model shows no space-time singularity and the expansion of the universe will continue forever, i.e., the future scenario of the universe attains Big Freeze. The model predicts the moderate inflationary scenario at the time of the evolution of the universe and it is consistent with $ Λ$CDM in late times. The consistency of the model has also been examined using recent observational Hubble dataset and supernovae dataset. Finally, the physical features of the model have been discussed in some detail.

gr-qc

Dynamics of a parametrized dark energy model in $f(R,T)$ gravity

We investigate a flat FLRW-model in $f(R,T)$-gravity, which includes the quadratic variation in scalar curvature $R$ and the linear term of the trace of the stress-energy tensor $T$. In turn, we establish the model has the behaviour of the late time Universe, which is accelerated expanding and ends up in a big rip. Using the parametrization of scale factor $a(t)$, we propose a model, which begins with point-type singularity, i.e., the model starts with a point of zero volume, infinite energy density and infinite temperature. The model's behaviour is accelerated expanding at present and $Λ$CDM in late times. Finally, the proposed model behaves like a quintessence dark energy model in the present time and is consistent with standard cosmology $Λ$CDM in late times.

gr-qc

Bouncing cosmology in modified gravity with higher-order curvature terms

A bouncing scenario of a flat homogeneous and isotropic universe is explored by using the reconstruction technique for the power-law parametrization of the Hubble parameter in a modified gravity theory with higher-order curvature and trace of the energy-momentum tensor terms. It is demonstrated that bouncing criteria are satisfied so that the cosmological initial singularity can be avoided. In addition, it is shown that the equation of state parameter crosses the line of the phantom divide. In the present scenario, the universe is filled with perfect fluid around the bouncing point, in which the universe becomes highly unstable and a big bounce can be realized. Furthermore, it is found that extremal acceleration occurs at the bouncing point.

gr-qc