Searcharxiv⌕ Search

arXiv subjects

F. F. Faria

Publications and source records attributed to F. F. Faria.

At least 19 recordsLinked to original sources
arXiv2025

Cosmic structure formation in massive conformal gravity

We study the evolution of cosmological density perturbations in massive conformal gravity (MCG). We show that conformal fermionic matter alone does not generate growing density perturbations in the subhorizon regime. By introducing a conformally coupled scalar field, however, an effective cold dark matter component emerges at the effective level. The resulting coupled perturbation equations admit growing solutions with a stronger effective gravitational interaction, allowing cosmic structure formation in MCG and potentially favoring earlier structure formation at high redshifts.

gr-qc↗
arXiv2025

On the entropy of the massive conformal gravity universe

We find that the total entropy of the massive conformal gravity universe is an increasing function of time, and therefore the cosmological model of the theory passes the generalized second law of thermodynamics test.

physics.gen-ph↗
arXiv2025

Singularities in massive conformal gravity

We study the quantum effects of big bang and black hole singularities on massive conformal gravity. We do this by analyzing the behavior of the on-shell effective action of the theory at these singularities. The result is that such singularities are harmless in MCG because the on-shell effective action of the theory does not diverge at them.

hep-th↗
arXiv2023

Early universe nucleosynthesis in massive conformal gravity

We study the dynamics of the early universe in massive conformal gravity. In particular, we show that the theory is consistent with the observed values of the primordial abundances of light elements if we consider the existence of right-handed sterile neutrinos.

physics.gen-ph↗
arXiv2022

Solar system tests for massive conformal gravity

We find the linearized gravitational field of a static spherically symmetric mass distribution in massive conformal gravity and test it with some solar system experiments. The result is that the theory agrees with the general relativistic observations in the solar system for a determined lower bound on the graviton mass.

gr-qc↗
arXiv2021

Conformal theory of everything

By using conformal symmetry we unify the standard model of particle physics with gravity in a consistent quantum field theory which describes all the fundamental particles and forces of nature.

hep-ph↗
arXiv2021

Late cosmology in massive conformal gravity

In this paper we find the cosmological solutions of the massive conformal gravity field equations in the presence of matter fields. In particular, we show that the solution of negative curvature is in good agreement with the late universe.

gr-qc↗
arXiv2020

Gravitational waves in massive conformal gravity

First, we obtain the plane wave solution of the linearized massive conformal gravity field equations. It is shown that the theory has seven physical plane waves. In addition, we investigate the gravitational radiation from binary systems in massive conformal gravity. We find that the theory with large graviton mass can reproduce the orbit of binaries by the emission of gravitational waves.

gr-qc↗
arXiv2019

On the vDVZ discontinuity in massive conformal gravity

By taking the massless limit of linearized massive conformal gravity coupled to a source, we show that the theory is free from the vDVZ discontinuity. This result is confirmed when we take the massless limit of the gravitational potential of the theory, which is shown to be finite at the origin.

hep-th↗
arXiv2019

Comment on "Astrophysical gravitational waves in conformal gravity"

Recently, in Phys. Rev. D 98, 084002 (2018), an investigation was carried out on the gravitational radiation from binary systems in conformal gravity and massive conformal gravity. According to the authors of the paper, these two theories differ only by the sign of a parameter in the matter action of a general conformal theory. For a negative parameter the general conformal theory indeed corresponds to conformal gravity. However, here, we argue that for a positive parameter the general conformal theory does not correspond to massive conformal gravity.

gr-qc↗
arXiv2017

Reply to "Comment on 'Quantum massive conformal gravity' by F. F. Faria"

Recently in (Eur. Phys. J. C 76:341, 2016) [arXiv:1604.08706], Myung has suggested that the renormalizability of massive conformal gravity is meaningless unless the massive ghost states of the theory are stable. Here we show that massive conformal gravity can be renormalizable having unstable ghost states.

gr-qc↗
arXiv2016

Quantum massive conformal gravity

We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed.

gr-qc↗
arXiv2014

Massive conformal gravity

In this article we construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depend on the metric tensor and a scalar field, which are considered as the only field variables. We find the vacuum field equations of the theory and the solution of its Newtonian limit.

gr-qc↗
arXiv2013

A new geometrical approach to metric-affine gravity

Here we consider a metric-affine theory of gravity in which the gravitational Lagrangian is the scalar curvature. The matter action is allowed to depend also on the torsion and the nonmetricity, which are considered as the field variables together with the metric. We find the field equations of the theory and show that they reduce to Einstein equations in vacuum

gr-qc↗
arXiv2012

Teleparallel gauge theory of gravity

In this work a tetrad theory of gravity, invariant under conformal transformations, is investigated. The action of the theory is similar to the action of Maxwell's electromagnetism. The role of the electromagnetic gauge potential is played by the trace of the torsion tensor of the Weitzenböck spacetime. It is shown that all static, spherically symmetric space-times, are solutions of the vacuum field equations. However, by fixing the gauge in the linearized form of the vacuum field equations, the usual Newtonian limit for the gravitational field is obtained.

gr-qc↗
arXiv2012

Conformally invariant teleparallel theories of gravity

We analyze the construction of conformal theories of gravity in the realm of teleparallel theories. We first present a family of conformal theories which are quadratic in the torsion tensor and are constructed out of the tetrad field and of a scalar field. For a particular value of a coupling constant, and in the gauge where the scalar field is restricted to assume a constant value, the theory reduces to the teleparallel equivalent of general relativity, and the tetrad field satisfies Einstein's equations. A second theory is formulated out of the tetrad field only, and is not equivalent to the usual Weyl Lagrangian. Therefore the latter is not the unique genuinely geometrical construction that yields a conformally invariant action. The teleparallel framework allows more possibilities for conformal theories of gravity.

gr-qc↗