English

Anisotropic fluid spheres in the framework of $f(R,\mathcal{T})$ gravity theory

General Relativity and Quantum Cosmology 2020-02-19 v1

Abstract

The main aim of this paper is to obtain analytic relativistic anisotropic spherical solutions in f(R,T\mathcal{T}) scenario. To do so we use modified Durgapal-Fuloria metric potential and the isotropic condition is imposed in order to obtain the effective anisotropic factor Δ~\tilde{\Delta}. Besides, a notable and viable election on f(R,T\mathcal{T}) gravity formulation is taken. Specifically f(R,T)=R+2χTf(R,\mathcal{T})=R+2\chi\mathcal{T}, where RR is the Ricci scalar, T\mathcal{T} the trace of the energy-momentum tensor and χ\chi a dimensionless parameter. This choice of f(R,T)f(R,\mathcal{T}) function modifies the matter sector only, including new ingredients to the physical parameters that characterize the model such as density, radial, and tangential pressure. Moreover, other important quantities are affected such as subliminal speeds of the pressure waves in both radial and transverse direction, observational parameters, for example, the surface redshift which is related with the total mass MM and the radius rsr_{s} of the compact object. Also, a transcendent mechanism like equilibrium through generalized Tolman-Oppenheimer-Volkoff equation and stability of the system are upset. We analyze all the physical and mathematical general requirements of the configuration taking M=1.04MM=1.04 M_{\odot} and varying χ\chi from 0.1-0.1 to 0.10.1. It is shown by the graphical procedure that χ<0\chi<0 yields to a more compact object in comparison when χ0\chi\geq0 (where χ=0.0\chi=0.0 corresponds to general relativity theory) and increases the value of the surface redshift. However, negative values of χ\chi introduce in the system an attractive anisotropic force (inward) and the configuration is completely unstable (corroborated employing Abreu's criterion). Furthermore, the model in Einstein gravity theory presents cracking while for χ>0\chi>0 the system is fully stable.

Keywords

Cite

@article{arxiv.1906.11756,
  title  = {Anisotropic fluid spheres in the framework of $f(R,\mathcal{T})$ gravity theory},
  author = {S. K. Maurya and Francisco Tello-Ortiz},
  journal= {arXiv preprint arXiv:1906.11756},
  year   = {2020}
}