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تسجيل مستخدم جديدAccelerating Universe in Hybrid and Logarithmic Teleparallel Gravity
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Teleparallel gravity is a modified theory of gravity for which the Ricci scalar $R$ of the underlying geometry in the action is replaced by an arbitrary functional form of torsion scalar $T$. In doing so, cosmology in $% f(T)$ gravity becomes greatly simplified owing to the fact that $T$ contains only the first derivatives of the vierbeins. The article exploits this appealing nature of $f(T)$ gravity and present cosmological scenarios from hybrid and logarithmic teleparallel gravity models of the form $% f=e^{mT}T^n $ and $f=Dlog(bT)$ respectively, where $m$, $n$, $D$ and $b$ are free parameters constrained to suffice the late time acceleration. We employ a well motivated parametrization of the deceleration parameter having just one degree of freedom constrained with a $chi^{2}$ test from 57 data points of Hubble data set in the redshift range $0.07<z<2.36$, to obtain the expressions of pressure, density and EoS parameter for both the teleparallel gravity models and study their temporal evolution. We find the deceleration parameter to experience a signature flipping for the $chi^{2}$ value of the free parameter at $z_{tr}simeq0.6$ which is consistent with latest Planck measurements. Next, we present few geometric diagnostics of this parametrization to understand the nature of dark energy and its deviation from the $Lambda$CDM cosmology. Finally, we study the energy conditions to check the consistency of the parameter spaces for both the teleparallel gravity models. We find the SEC to violate for both the models which is an essential recipe to obtain an accelerating universe.
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The $f(R,T)$ theory of gravitation is an extended theory of gravitation in which the gravitational action contains both the Ricci scalar $R$ and the trace of energy momentum tensor $T$ and hence the cosmological models based on $f(R,T)$ gravity are e
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Teleparallel gravity is a modified theory of gravity in which the Ricci scalar $R$ of the Lagrangian replaced by the general function of torsion scalar $T$ in action. With that, cosmology in teleparallel gravity becomes profoundly simplified because
it is second-order theory. The article present a complete cosmological scenario in $f(T)$ gravity with $f(T)=T+beta(-T)^{alpha}$, where $alpha,$ and $beta$ are model parameters. We present the profiles of energy density, pressure, and equation of state (EoS) parameter. Next to this, we employ statefinder diagnostics to check deviation from the $Lambda$CDM model as well as the nature of dark energy. Finally, we discuss the energy conditions to check the consistency of our model and observe that SEC violates in the present model supporting the acceleration of the Universe as per present observation.
In the present work, a new form of the logarithmic shape function is proposed for the linear $f(R,T)$ gravity, $f(R,T)=R+2lambda T$ where $lambda$ is an arbitrary coupling constant, in wormhole geometry. The desired logarithmic shape function accompl
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