arXiv subjects

Jeferson de Oliveira

Publications and source records attributed to Jeferson de Oliveira.

At least 19 recordsLinked to original sources

arXiv2026

Quasinormal modes of a quantum inspired black hole in four dimensions with cosmological constant

We study the scalar and Dirac perturbations of quantum-corrected black holes with cosmological constant. Using two different methods (WKB and double-null characteristic integration) we compute the quasinormal modes (QNMs) of de Sitter and Anti-de Sitter solutions considering linear field perturbations in the background geometry. In the limit of general relativity black holes our methods demonstrate good convergence with the available results in literature. In the presence of an extra quantum parameter we verify that all perturbations are stable evolving in towers of quasinormal oscillations. We scrutinize the spectra of both dS and AdS solutions studying the influence of that extra parameter in the frequencies.

gr-qc↗

arXiv2026

Causal structure of black holes immersed in a Chaplygin-like dark fluid environment: Horizons and singularities

In the present work, we study the causal structure of spherically symmetric black holes immersed in a Chaplygin-like dark fluid, emphasizing the impact of the fluid parameters on curvature and horizon formation. We show that the spacetime curvature is significantly stronger than in its similar counterpart, the Reissner-Nordstrom-de Sitter geometry with the same mass and charge, leading to modifications of the internal causal structure. For the presence of horizons the Chaplygin black hole possesses an upper bound $Q \approx 0.556219 M$, which is much smaller than that for Reissner-Nordstrom spacetime $Q_{\text{critical}} = M$ or of the Reissner-Nordstrom-de Sitter case $Q_{\text{critical}} = 3M/(2\sqrt{2})$, indicating that the black holes immersed in a Chaplygin-like dark fluid reach the extremal regime more easily. We derive a second critical condition for the Chaplygin cosmological parameter $B$, $B_c Q_c^4 = 4/3^9$, setting an upper bound on $B$ for a multi-horizon solution.

gr-qc↗

arXiv2024

Aspects of regular and singular electromagnetic-generalized-quasitopological-gravities black holes in (2+1) dimensions

We investigate quasitopological black holes in $(2+1)$ dimensions in the context of electromagnetic-generalized-quasitopological-gravities (EM-GQT). For three different families of geometries of quasitopological nature, we study the causal structure and their response to a probe scalar field. To linear order, we verify that the scalar field evolves stably, decaying in different towers of quasinormal modes. The studied black holes are either charged geometries (regular and singular) or a regular Bañados-Teitelboim-Zanelli (BTZ)-like black hole, both coming from the EM-GQT theory characterized by nonminimal coupling parameters between gravity and a background scalar field. We calculate the quasinormal modes applying different numerical methods with convergent results between them. The oscillations demonstrate a very peculiar structure for charged black holes: in the intermediate and near extremal cases, a particular scaling arises, similar to that of the rotating BTZ geometry, with the modes being proportional to the distance between horizons. For the single horizon black hole solution, we identify the presence of different quasinormal families by analyzing the features of that spectrum. In all three considered geometries, no instabilities were found.

gr-qc↗

arXiv2022

Gauss-Bonnet black holes in (2+1) dimensions: Perturbative aspects and entropy features

We investigate some aspects of the $(2+1)$-dimensional Gauss-Bonnet black hole proposed in [1][2]. The perturbations of scalar and massless spinorial fields are studied suggesting the dynamical stability of the geometry. The field evolution is analyzed calculating the quasinormal modes for different parameters and exploring the influence of the coupling constant of the theory. The hydrodynamical modes are also obtained in the small coupling limit. Furthermore, the entropy bound and the dominant semiclassical correction to the black hole entropy are calculated.

gr-qc↗

arXiv2021

Superradiance and instabilities in black holes surrounded by anisotropic fluids

In this paper we analyze the propagation of a charged scalar field in a Reissner-Nordström black hole endowed with one anisotropic fluid that can play the role of a cosmological term for certain set of parameters. The evolution of a scalar wave scattering is examined giving rise to the same superradiant scattering condition as in the de Sitter case. In addition, an analysis of the modes coming from the application of quasinormal boundary conditions is presented. Some special cases displaying analytical solutions for the quasinormal frequencies are discussed. Moreover, the superradiant condition is adapted to the quasinormal problem triggering unstable modes, what is confirmed by our numerical analysis.

gr-qc↗

arXiv2021

Holographic Phase Transitions in (2+1)-dimensional black hole spacetimes in NMG

In this work we aim at the question of holographic phase transitions in two dimensional systems with Lifshitz scaling. We consider the gravity side candidate for a dual description as the black hole solution of New Massive Gravity (NMG) with Lifshitz scaling. We discuss the effects due to the Lifshitz scaling in the AGGH (Ayon-Beato-Garbarz-Giribet-Hassaïıne) solution in comparison with the BTZ (Bañados-Teitelboim-Zanelli) black hole. Likewise, we compute the order parameter and it indicates a second order phase transition in a (1+1) dimension Lifshitz boundary.

hep-th↗

arXiv2020

Analytical correspondence between shadow radius and black hole quasinormal frequencies

We consider the equivalence of quasinormal modes and geodesic quantities recently brought back due to the black hole shadow observation by Event Horizon Telescope. Using WKB method we found an analytical relation between the real part of quasinormal frequencies at the eikonal limit and black hole shadow radius. We verify this correspondence with two black hole families in $4$ and $D$ dimensions, respectively.

gr-qc↗

arXiv2020

Late-time tails, entropy aspects, and stability of black holes with anisotropic fluids

In this work we consider black holes surrounded by anisotropic fluids in four dimensions. We first study the causal structure of these solutions showing some similarities and differences with Reissner-Nordström-de Sitter black holes. In addition, we consider scalar perturbations on this background geometry and compute the corresponding quasinormal modes. Moreover, we discuss the late-time behavior of the perturbations finding an interesting new feature, i.e., the presence of a subdominant power-law tail term. Likewise, we compute the Bekenstein entropy bound and the first semiclassical correction to the black hole entropy using the brick wall method, showing their universality. Finally, we also discuss the thermodynamical stability of the model.

gr-qc↗

arXiv2019

Dynamical evolution of non-minimally coupled scalar field in spherically symmetric de Sitter spacetimes

We investigate the dynamical behavior of a scalar field non-minimally coupled to Einstein's tensor and Ricci scalar in geometries of asymptotically de Sitter spacetimes. We show that the quasinormal modes remain unaffected if the scalar field is massless and the black hole is electrically chargeless. In the massive case, the coupling of both parameters produces a region of instability in the spacetime determined by the geometry and field parameters. In the Schwarzschild case, every solution for the equations of motion with $\ell>0$ has a range of values of the coupling constant that produces unstable modes. The case $\ell=0$ is the most unstable one, with a threshold value for stability in the coupling. For the charged black hole, the existence of a range of instability in $η$ is strongly related to geometry parameters presenting a region of stability independent of the chosen parameter.

gr-qc↗

arXiv2019

Instability of Reissner-Nordström-AdS black hole under perturbations of a scalar field coupled to Einstein tensor

We study the instability of a Reissner-Nordström-AdS (RNAdS) black hole under perturbations of a massive scalar field coupled to Einstein tensor. Calculating the potential of the scalar perturbations we find that as the strength of the coupling of the scalar to Einstein tensor is increasing, the potential develops a negative well outside the black hole horizon, indicating an instability of the background RNAdS. We then investigate the effect of this coupling on the quasinormal modes. We find that there exists a critical value of the coupling which triggers the instability of the RNAdS. We also find that as the charge of the RNAdS is increased towards its extremal value, the critical value of the derivative coupling is decreased.

gr-qc↗

arXiv2019

Vectorial and spinorial perturbations in Galileon Black Holes: Quasinormal modes, quasiresonant modes and stability

In this work we have considered a model that includes the interaction of gravity and matter fields with Galilean invariance (the so-called derivative coupling) as well as some corresponding black hole type solutions. Quasinormal perturbations of two kinds of matter fields have been computed by different methods. The effect of the derivative coupling in the quasinormal spectrum has been analyzed and evaluated.

gr-qc↗

arXiv2018

Three-dimensional black holes with quintessence

We study a quintessential black hole solution in three dimensions, with mass and quintessence charge. By exploring the Carter-Penrose diagram, we show the presence of spacelike and lightlike singularities in the metric, given different values for the quintessence parameter, as well as an AdS-like spatial infinity and event horizon encapsulating the singularity. We also study the propagation of scalar and Dirac (Weyl) fields around the black hole solutions with different quintessence charges obtaining the quasinormal spectra for both fields using two different numerical methods with good agreement between the data. In both cases, the presence of quintessence increases the imaginary part of the quasinormal mode, since this is related to the event horizon of the solution, preserving the interpretation of this quantity as relaxation time in the corresponding CFT. We also investigate the behavior of high-temperature scalar field modes, demonstrating the presence of the so-called hydrodynamical limit, differently from the BTZ black hole, for which no such modes exist.

gr-qc↗

arXiv2015

Holographic phase transition and Quasinormal modes in Lovelock gravity

In this work we aim at discussing the effects of higher order corrections to curvature on the Lovelock AdS black holes quasinormal spectrum and, in the context of gauge/gravity correspondence, their consequences for the formation of holographic superconductors. We also explore the hydrodynamic limit of the $U(1)$ gauge field perturbations in $d$ dimensions.

hep-th↗

arXiv2013

The AdS/CFT relation, quasi-normal modes and applications

Here we present a fast review of some of developments and new results concerning applications of gravity in the context of the AdS/CFT correspondence, in brane world perturbations as well as in holographic superconductors. We also discuss the structure of the phase transitions in a more general set up defined by the quasi-normal oscillations in the bulk, which signalize a very complex structure of the phase transition at the border.

hep-th↗

arXiv2013

Quasinormal modes and thermodynamical aspects of the 3D Lifshitz black hole

We consider scalar and spinorial perturbations on a background described by a $z=3$ three-dimensional Lifshitz black hole. We obtained the corresponding quasinormal modes which perfectly agree with the analytical result for the quasinormal frequency in the scalar case. The numerical results for the spinorial perturbations reinforce our conclusion on the stability of the model under these perturbations. We also calculate the area spectrum, which prove to be equally spaced, as an application of our results.

hep-th↗

arXiv2012

Scalar field propagation in higher dimensional black holes at a Lifshitz point

We study the complete time evolution of scalar fields propagating in space-times of higher dimensional Lifshitz Black Holes with dynamical critical exponent $z=2$, obtained from a theory including the most general quadratic curvature corrections to Einstein-Hilbert gravity in $D$ dimensions. We also computed the quasinormal spectrum after performing a numerical integration and solving exactly the Klein-Gordon equation obeyed by the massive scalar field. We found that quasinormal modes are purely imaginary for all dimensions.

gr-qc↗

arXiv2012

Stability Analysis and Area Spectrum of 3-Dimensional Lifshitz Black Holes

In this work, we probe the stability of a $z=3$ three-dimensional Lifshitz black hole by using scalar and spinorial perturbations. We found an analytical expression for the quasinormal frequencies of the scalar probe field, which perfectly agree with the behavior of the quasinormal modes obtained numerically. The results for the numerical analysis of the spinorial perturbations reinforce the conclusion of the scalar analysis, i.e., the model is stable under scalar and spinor perturbations. As an application we found the area spectrum of the Lifshitz black hole, which turns out to be equally spaced.

hep-th↗

arXiv2011

Three dimensional Lifshitz black hole and the Korteweg-de Vries equation

We consider a solution of three dimensional New Massive Gravity with a negative cosmological constant and use the AdS/CTF correspondence to inquire about the equivalent two dimensional model at the boundary. We conclude that there should be a close relation with the Korteweg-de Vries equation.

hep-th↗