Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTraversable wormholes in the traceless $f(R,T)$ gravity
81
0
0.0
(
0
)
Added by
Pardyumn Kumar Sahoo
Publication date
2020
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
We present a traversable wormhole solution using the traceless $f(R,T)$ theory of gravity. In the $f(R,T)$ gravity, the Ricci scalar $R$ in the Einstein-Hilbert action is replaced by a function of $R$ and trace of the energy momentum tensor $T$. The traceless version of the $f(R,T)$ gravity gives rise to a possible wormhole geometry without need for exotic matter, which violates the principle of causality. Using a physically plausible ansatz for the wormholes shape function, the traceless field equations lead to compliance with the weak energy condition at very well defined intervals of the coupling constant $lambda$ in the $f(R,T)=R+2lambda T$ form. Our solution leads to other well-behaved energy conditions considering some possible values of the parameter $omega$ in the equation of state $p_r=omega rho$, with $p_r$ being the radial pressure and $rho $ the density. The energy conditions are obeyed in the ranges $lambda < -4pi$ and $omega > -1$. Through the calculation of the Volume Integral Quantifier, one sees that this wormholes can be traversable and respect the causality, since the amount of exotic matter in its interior can be arbitrarily small.
rate research
Read More
Wormholes are a solution for General Relativity field equations which characterize a passage or a tunnel that connects two different regions of space-time and is filled by some sort of exotic matter, that does not satisfy the energy conditions. On the other hand, it is known that in extended theories of gravity, the extra degrees of freedom once provided may allow the energy conditions to be obeyed and, consequently, the matter content of the wormhole to be non-exotic. In this work, we obtain, as a novelty in the literature, solutions for charged wormholes in the $f(R,T)$ extended theory of gravity. We show that the presence of charge in these objects may be a possibility to respect some stability conditions for their metric. Also, remarkably, the energy conditions are respected in the present approach.
In this work we propose the modelling of static wormholes within the $f(R,T)$ extended theory of gravity perspective. We present some models of wormholes, which are constructed from different hypothesis for their matter content, i.e., different relations for their pressure components (radial and lateral) and different equations of state. The solutions obtained for the shape function of the wormholes obey the necessary metric conditions. They show a behaviour similar to those found in previous references about wormholes, which also happens to our solutions for the energy density of such objects. We also apply the energy conditions for the wormholes physical content.
Traversable wormholes, studied by Morris and Thorne cite{Morris1} in general relativity, are investigated in this research paper in $f(R,T)$ gravity by introducing a new form of non-linear $f(R,T)$ function. By using this novel function, the Einsteins field equations in $f(R,T)$ gravity are derived. To obtain the exact wormhole solutions, the relations $p_t=omegarho$ and $p_r=sinh(r)p_t$, where $rho$ is the energy density, $p_r$ is the radial pressure and $p_t$ is the tangential pressure, are used. Other than these relations, two forms of shape function defined in literature are used, and their suitability is examined by exploring the regions of validity of null, weak, strong and dominant energy conditions . Consequently, the radius of the throat or the spherical region, with satisfied energy conditions, is determined and the presence of exotic matter is minimized.
The present paper is aimed at the study of traversable wormholes in $f(R)$ gravity with a viable $f(R)$ function defined as $f(R)=R-mu R_cBig(frac{R}{R_c}Big)^p$, where $R$ is scalar curvature, $mu$, $R_c$ and $p$ are constants with $mu, R_c>0$ and $0<p<1$ citep{Amendola}. The metric of wormhole is dependent on shape function $b(r)$ and redshift function $phi(r)$ which characterize its properties, so the shape function and redshift function play an important role in wormhole modeling. In this work, the wormhole solutions are determined for (i) $phi(r)=frac{1}{r}$ and (ii) $phi(r)=c$ (constant) with $b(r)=frac{r}{exp(r-r_0)}$ citep{godani1}. Further, the regions respecting the energy conditions are investigated.
In this paper, we employ mimetic $f(R,T)$ gravity coupled with Lagrange multiplier and mimetic potential to yield viable inflationary cosmological solutions consistent with latest Planck and BICEP2/Keck Array data. We present here three viable inflationary solutions of the Hubble parameter ($H$) represented by $H(N)=left(A exp beta N+B alpha ^Nright)^{gamma }$, $H(N)=left(A alpha ^N+B log Nright)^{gamma }$, and $H(N)=left(A e^{beta N}+B log Nright)^{gamma }$, where $A$, $beta$, $B$, $alpha$, $gamma$ are free parameters, and $N$ represents the number of e-foldings. We carry out the analysis with the simplest minimal $f(R,T)$ function of the form $f(R,T)= R + chi T$, where $chi$ is the model parameter. We report that for the chosen $f(R,T)$ gravity model, viable cosmologies are obtained compatible with observations by conveniently setting the Lagrange multiplier and the mimetic potential.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
