arXiv subjects

J. L. Neto

Publications and source records attributed to J. L. Neto.

3 recordsLinked to original sources

arXiv2021

Formation and Evolution of Wakes in the Spacetime Generated by a Cosmic String in $f(R)$ Theory of Gravity

The formation and evolution of cosmic string wakes in the framework of a $f(R)$ theory of gravity are investigated in this work. We consider a simple model in which baryonic matter flows past a cosmic string. We treat this problem in the Zel'dovich approximation. We compare our results with previous results obtained in the context of General Relativity and Scalar-Theories of Gravity.

gr-qc↗

arXiv2017

A nearly cylindrically symmetric source in the Brans-Dicke gravity as the generator of the rotational curves of the galaxies

Observation shows that the velocities of stars grow by approximately 2 to 3 orders of magnitude when the distances from the centers of the galaxies are in the range of $0.5$ kpc to $82.3$ kpc, before they begin to tend to a constant value. Up to know, the reason for this behavior is still a matter for debate. In this work, we propose a model which adequately describes this unusual behavior using a (nearly) cylindrical symmetrical solution in the framework of a scalar-tensor-like (the Brans-Dicke model) theory of gravity.

gr-qc↗

arXiv2015

Thermodynamical Analysis of a Black Hole with a Global Monopole Within a Class of a f(R) Gravity

We analyze the thermodynamics of a black hole in a region that contains a global monopole in the framework of a particular class of a f(R) gravity. Specifically, we study the case in which df(R)/dR = F(R) is a power law function of the radial coordinate of the monopole spacetime, i.e., F(r) = 1 + ψ_n r^n, where ψ_n is the fine-tuned parameter corresponding to the f(R) gravity. We obtain explicit expressions for the local thermodynamic quantities of the black hole as a function of the event horizon, the parameter describing the monopole and the measurable corrections due to the f(R) theory modifications of the General Relativity. We also discussed the implications of the particular case of n=2, where the parameter ψ_2 can be related to a positive cosmological constant, that in monopole presence is characterized by a non-trivial topology observed as a deficit solid angle.

hep-th↗