arXiv subjects

A. R. Soares

Publications and source records attributed to A. R. Soares.

13 recordsLinked to original sources

arXiv2026

Light propagation and gravitational lensing effects in charged Kalb-Ramond spacetime in nonlinear electrodynamics

In this work, we theoretically investigate the deflection of light for strong- and weak-field regimes in the background of an electrically charged BH described in Kalb-Ramond gravity, which introduces the Lorentz symmetry violation parameter $l$, as well as the control of the degree of nonlinearity incorporated by electrodynamics through the parameter $γ$. We analytically constructed the expansion coefficients in both limits and used them as a basis to investigate gravitational lensing effects through observables, taking into account the variation of the parameters involved in the model, both for the canonical field and the phantom case.

gr-qc↗

arXiv2026

Light propagation and quasinormal modes of a topologically charged Schwarzschild-Klinkhamer wormhole

In this work, we present a theoretical analysis of null geodesics, critical photon orbits, and shadow formation associated with a wormhole generated by a geometric defect. The propagation of light in this spacetime is examined through the deflection angle in both weak- and strong-field regimes. Analytical expansions are derived in each regime and employed to characterize gravitational lensing observables. By varying the global monopole charge, we evaluate its impact on these observables and determine parameter ranges that may be accessible to current or future observational probes. Finally, we calculate the quasinormal modes as well as the time-domain solution for scalar perturbations as well.

gr-qc↗

arXiv2026

Black Holes Surrounded by Perfect Fluid Dark Matter in Eddington-inspired Born-Infeld Gravity

In this work, we exactly derive the solution for the gravitational field of a black hole in Eddington-inspired Born-Infeld (EiBI) gravity, surrounded by perfect fluid dark matter. We analyze how the event horizon and the black hole dimensions vary as a function of the model parameters, exploring the fundamental properties of this spacetime. Through numerical investigations, we examine the geodesics of massive particles and demonstrate the high sensitivity of stable circular orbits to the system's coupling constants.

gr-qc↗

arXiv2026

Numerical study of non-relativistic quantum systems and small oscillations induced in a helically twisted geometry

We investigate bound states of a non-relativistic scalar particle in a three-dimensional helically twisted (torsional) geometry, considering both the free case and the presence of external radial interactions. The dynamics is described by the Schrödinger equation on a curved spatial background and, when included, by minimal coupling to a magnetic vector potential incorporating an Aharonov--Bohm flux. After separation of variables, the problem reduces to a one-dimensional radial eigenvalue equation governed by an effective potential that combines torsion-induced Coulomb-like and centrifugal-like structures with magnetic/flux-dependent terms and optional model interactions. Because closed-form analytic solutions are not reliable over the parameter ranges required for systematic scans, we compute spectra and eigenfunctions numerically by formulating the radial equation as a self-adjoint Sturm--Liouville problem and solving it with a finite-difference discretization on a truncated radial domain, with explicit convergence control. We analyze four representative scenarios: (i) no external potential, (ii) Cornell-type confinement, (iii) Kratzer-type interaction, and (iv) the small-oscillation regime around the minimum of a Morse potential. We present systematic trends of the low-lying levels as functions of the torsion parameter, magnetic field, and azimuthal sector, and we show that geometric couplings alone can produce effective confinement even in the absence of an external interaction.

quant-ph↗

arXiv2025

Light deflection and gravitational lensing effects in acoustic black-bounce spacetime

In the present work, we analyze the gravitational deflection for a light beam in the weak and strong field regimes for the gravitational analogue geometry of an acoustic black hole (ABH) and acoustic black-bounce (ABB). Motivationally, the first spacetime arises as an exact solution of the field equations for gravitational black holes (BHs) in an Einstein-scalar-Gauss-Bonnet theory (EsGB) \cite{3}. In contrast, the second model arises from the combination of phantom scalar field and nonlinear electrodynamics in general relativity (GR) \cite{INTRO24}. We construct analytical expressions for the angular deflection of light in both limits and, from them, analyze the construction of the observables, which allow us to relate theoretical models to observational data. We compare these observables and show how much they differ from those obtained in the Schwarzschild solution.

gr-qc↗

arXiv2025

Light deflection and gravitational lensing effects inspired by loop quantum gravity

In the present work, we theoretically investigate light deflection in the weak and strong field regimes for two regular spacetimes with corrections from loop quantum gravity. We treat analytically the expansions for both limits and use them as a basis for investigating gravitational lensing observables. We analyze and provide reasonable values for observables related to the second model that observational tools may be able to detect.

gr-qc↗

arXiv2024

Topologically Charged Holonomy corrected Schwarzschild black hole lensing

In this paper, we theoretically investigate the deflection of light produced by a topologically charged Holonomy corrected Schwarzschild black hole. The study is carried out both in the weak field limit and in the strong field limit. We analytically deduced the expansions for light deflection in the two limits and, from them, we determined the observables in order to provide elements so that observational tools are able to identify these solutions. We model possible gravitational scenarios in order to verify the possible gravitational characteristics of the solution.

gr-qc↗

arXiv2023

Holonomy corrected Schwarzschild black hole lensing

In the present work, we theoretically investigate gravitational lensing in the spacetime of a holonomy corrected Schwarzschild black hole. Analytical expressions for the light deflection angle are obtained in both the weak field limit and the strong field limit. Furthermore, we analyze observables, such as relativistic images and magnifications, and compare the results with those expected in a Schwarzschild spacetime. We discuss the possibilities and difficulties of investigating such a solution in practice.

gr-qc↗

arXiv2023

Gravitational lensing in a topologically charged Eddington-inspired Born-Infeld spacetime

In the present paper, we study several aspects of gravitational lensing caused by a topologically charged Monopole/Wormhole, both in the weak field limit and in the strong field limit. We calculate the light deflection and then use it to determine the observables, with which one can investigate the existence of these objects through observational tools. We emphasize that the presence of the topological charge produces changes in the observables in relation to the case of General Relativity Ellis-Bronnikov wormhole.

gr-qc↗

arXiv2020

Strong gravitational lensing in a spacetime with topological charge within the Eddington-inspired Born-Infeld gravity

In this work we calculate the angular deflection of light in the strong field limit in two spacetimes which were previously studied within the Eddington-inspired Born-Infeld gravity (EiBI), namely, a black hole and a wormhole, both with topological charge. We show that the presence of the parameters characterizing EiBI and the topological charge promote significant changes in the angular deflection of light with respect to that one obtained in Schwarzschild spacetime. Using the expression for angular deflection in the strong field limit, we calculate the position and magnification of the respective relativistic images.

gr-qc↗

arXiv2020

Gravitational lensing in a black-bounce traversable wormhole spacetime

In this work, we calculate the deflection angle of light in a spacetime that interpolates between regular black holes and traversable wormholes, depending on the free parameter of the metric. Afterwards, this angular deflection is substituted into the lens equations which allows to obtain physically measurable results, such as the position of the relativistic images and the magnifications.

gr-qc↗

arXiv2019

Nonlinear $σ$-models in the Eddington-inspired Born-Infeld Gravity

In this paper we consider two different nonlinear $σ$-models minimally coupled to Eddington-inspired Born-Infeld gravity. We show that the resultant geometries represent minimal modifications with respect to those found in GR, though with important physical consequences. In particular, wormhole structures always arise, though this does not guarantee by itself the geodesic completeness of those space-times. In one of the models, quadratic in the canonical kinetic term, we identify a subset of solutions which are regular everywhere and are geodesically complete. We discuss characteristic features of these solutions and their dependence on the relationship between mass and global charge.

hep-th↗

arXiv2019

Global Monopole in Palatini f(R) gravity

We consider the space-time metric generated by a global monopole in an extension of General Relativity (GR) of the form $f(\mathcal{R})=\mathcal{R}-λ\mathcal{R}^2$. The theory is formulated in the metric-affine (or Palatini) formalism and exact analytical solutions are obtained. For $λ<0$, one finds that the solution has the same characteristics as the Schwarzschild black hole with a monopole charge in Einstein's GR. For $λ>0$, instead, the metric is more closely related to the Reissner-Nordström metric with a monopole charge and, in addition, it possesses a wormhole-like structure that allows for the geodesic completeness of the space-time. Our solution recovers the expected limits when $λ=0$ and also at the asymptotic far limit. The angular deflection of light in this spacetime in the weak field regime is also calculated.

gr-qc↗