Luis Cesar Nunes dos Santos
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Luis Cesar Nunes dos Santos has a total of 40 co-authors. Here are the top co-authors by number of shared publications:
- Franciele M. da Silva
CFM—Universidade Federal de Santa Catarina
29 shared publications - Valdir Barbosa Bezerra
Physics Department, Federal University of Paraíba, João Pessoa, Brazil
15 shared publications - Celso de Camargo Barros
Departamento de Física, CFM, Universidade Federal de Santa Catarina, Florianópolis, Brazil
14 shared publications - Clésio E. Mota
Departamento de Fisica CFM -Universidade Federal de Santa Catarina C.P. 476 CEP 88.040-900 Florianópolis SC Brasil
13 shared publications - Iarley P. Lobo
Universidade Federal da Paraíba
11 shared publications - Leonardo G. Barbosa
CFM-Universidade Federal de Santa Catarina
11 shared publications
Latest Publications
- Open Access
- 6 June 2026
- Published by Elsevier in Physics Letters B
- Vol. 879
Black string immersed in perfect fluid dark matter
- 6 June 2026
- Published by Elsevier in Physics Letters B
- Vol. 879
Open AccessBlack string immersed in perfect fluid dark matter
- Open Access
- 10 April 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (4)
Scalar bosons with Coulomb potentials in a space with dual topological defects in rainbow gravity
This work studies the relativistic quantum dynamics of scalar bosons in a spacetime containing both a cosmic string and a global monopole within the framework of Rainbow Gravity. An effective metric is constructed to describe the combined topological defects together with the energy-dependent deformation of spacetime. The Klein–Gordon equation is formulated in this background, including scalar, vector, and nonminimal couplings, and its solutions are obtained by separation of variables. Generalized Coulomb-type interactions are considered, allowing a unified analysis of scattering and bound states. The bound-state spectrum is determined from the poles of the corresponding S -matrix. Two specific choices of rainbow functions are examined, and their influence on the energy spectrum is analyzed through numerical calculations and, in suitable limits, analytical approximations. The results show how the interplay between topological defects and rainbow gravity corrections affects the spectral properties of scalar bosons, while known results are consistently recovered in appropriate limits.
- 10 April 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (4)
Open AccessScalar bosons with Coulomb potentials in a space with dual topological defects in rainbow gravity
This work studies the relativistic quantum dynamics of scalar bosons in a spacetime containing both a cosmic string and a global monopole within the framework of Rainbow Gravity. An effective metric is constructed to describe the combined topological defects together with the energy-dependent deformation of spacetime. The Klein–Gordon equation is formulated in this background, including scalar, vector, and nonminimal couplings, and its solutions are obtained by separation of variables. Generalized Coulomb-type interactions are considered, allowing a unified analysis of scattering and bound states. The bound-state spectrum is determined from the poles of the corresponding S -matrix. Two specific choices of rainbow functions are examined, and their influence on the energy spectrum is analyzed through numerical calculations and, in suitable limits, analytical approximations. The results show how the interplay between topological defects and rainbow gravity corrections affects the spectral properties of scalar bosons, while known results are consistently recovered in appropriate limits.
- Open Access
- 16 March 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (3)
Kiselev black strings in f(R, T) gravity
In this work, we investigate exact black string solutions in the context of f ( R , T ) gravity. Adopting the specific form $$f(R,T) = R + 2\chi T$$ , we consider an anisotropic Kiselev fluid as the matter content and obtain static cylindrical solutions, which are then extended to the rotating case through a suitable coordinate transformation. The influence of the quintessence state parameter $$w_q$$ and the matter–geometry coupling constant $$\chi $$ on the geometry is analyzed. We examine the weak, null, and strong energy conditions, identifying the regions in the parameter space where they are satisfied. Furthermore, we apply the Hamilton–Jacobi method to study the tunneling of scalar particles across the event horizon and derive the corresponding Hawking temperature. The thermodynamic stability of the solutions is investigated by computing the heat capacity, and the conditions for phase transitions are discussed. The results provide a characterization of black strings in f ( R , T ) gravity surrounded by quintessence, highlighting the combined effects of anisotropic matter and modified gravity on their physical properties.- 16 March 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (3)
Open AccessKiselev black strings in f(R, T) gravity
In this work, we investigate exact black string solutions in the context of f ( R , T ) gravity. Adopting the specific form $$f(R,T) = R + 2\chi T$$ , we consider an anisotropic Kiselev fluid as the matter content and obtain static cylindrical solutions, which are then extended to the rotating case through a suitable coordinate transformation. The influence of the quintessence state parameter $$w_q$$ and the matter–geometry coupling constant $$\chi $$ on the geometry is analyzed. We examine the weak, null, and strong energy conditions, identifying the regions in the parameter space where they are satisfied. Furthermore, we apply the Hamilton–Jacobi method to study the tunneling of scalar particles across the event horizon and derive the corresponding Hawking temperature. The thermodynamic stability of the solutions is investigated by computing the heat capacity, and the conditions for phase transitions are discussed. The results provide a characterization of black strings in f ( R , T ) gravity surrounded by quintessence, highlighting the combined effects of anisotropic matter and modified gravity on their physical properties. - 12 March 2026
- Published by American Physical Society (APS) in Physical Review D
- Vol. 113 (6)
Hyperons and Δ ’s in rotating protoneutron stars: Local properties
- 12 March 2026
- Published by American Physical Society (APS) in Physical Review D
- Vol. 113 (6)
Hyperons and Δ ’s in rotating protoneutron stars: Local properties
- 12 December 2025
- Published by Elsevier in Annals of Physics
- Vol. 485
Scalar bosons in the context of gravity’s rainbow in the double defect spacetime
- 12 December 2025
- Published by Elsevier in Annals of Physics
- Vol. 485
Scalar bosons in the context of gravity’s rainbow in the double defect spacetime
- Open Access
Quantum field theory-inspired cure for black hole singularities
In recent years, there has been a growing interest in the study of regular black holes, driven by the search for singularity-free geometries. This research has revealed intriguing similarities between the regularization mechanisms used in black hole models and those employed in quantum field theory, such as the introduction of exponential suppression or energy cutoffs. We propose a systematic exponential cutoff regularization scheme for static, spherically symmetric black hole solutions in general relativity. The method explored in this paper serves as an alternative to the black-bounce singularity suppression mechanism proposed by Simpson and Visser, which involves a coordinate remapping $r \rightarrow\sqrt{r^2+a^2}$, as well as to the mechanism proposed by Bronnikov, which employs a Bardeen-type remapping in the metric. The method presented here introduces exponential factors in the mass function, smoothing curvature divergences and ensuring geodesic completeness under specific conditions. This approach allows the regularization of known singular spacetimes without altering their asymptotic structure. We analyze curvature invariants, horizon formation, and thermodynamic properties, showing that the regularized geometries avoid singularities while maintaining physical consistency. As examples of application, we regularize the Schwarzschild black hole and present a novel regularized Kiselev solution. The method provides a unified framework to systematically generate singularity-free black holes within classical general relativityOpen AccessQuantum field theory-inspired cure for black hole singularities
In recent years, there has been a growing interest in the study of regular black holes, driven by the search for singularity-free geometries. This research has revealed intriguing similarities between the regularization mechanisms used in black hole models and those employed in quantum field theory, such as the introduction of exponential suppression or energy cutoffs. We propose a systematic exponential cutoff regularization scheme for static, spherically symmetric black hole solutions in general relativity. The method explored in this paper serves as an alternative to the black-bounce singularity suppression mechanism proposed by Simpson and Visser, which involves a coordinate remapping $r \rightarrow\sqrt{r^2+a^2}$, as well as to the mechanism proposed by Bronnikov, which employs a Bardeen-type remapping in the metric. The method presented here introduces exponential factors in the mass function, smoothing curvature divergences and ensuring geodesic completeness under specific conditions. This approach allows the regularization of known singular spacetimes without altering their asymptotic structure. We analyze curvature invariants, horizon formation, and thermodynamic properties, showing that the regularized geometries avoid singularities while maintaining physical consistency. As examples of application, we regularize the Schwarzschild black hole and present a novel regularized Kiselev solution. The method provides a unified framework to systematically generate singularity-free black holes within classical general relativity - Open Access
Hyperons and $Δ$'s in rotating protoneutron stars: Local properties
The structural evolution of rotating protoneutron stars encodes essential information about their observable signatures, while microscopic properties provide complementary knowledge to advance observational investigations. Using a relativistic mean-field model with density-dependent couplings that account for temperature and particle composition, we investigate rotation, neutrino-emission-driven changes in angular momentum, particle distributions, temperature profiles, and sound speed to probe the internal dynamics of protoneutron star matter. Additionally, we track the evolution of macroscopic quantities such as energy distribution and gravitational mass and establish direct links between microphysics and global evolution. Extending the framework of Phys. Rev. D 112, 023007 (2025), which focuses on the global properties of rotating protoneutron star evolution, our results reveal that protoneutron star deformation and thermal evolution are governed by angular momentum, mass, and composition. Exotic matter (hyperons and $Δ$-resonances) and rapid rotation enhance deformation leading to a reduction in core temperature, whereas slowly rotating stars like PSR J0740$+$6620 remain nearly spherical. Our predicted equatorial radii for PSR J0740$+$6620, $13.0\ \mathrm{km} < R_e < 13.5\ \mathrm{km}$, are consistent with NICER measurements. These findings constrain the EoS, requiring a self-consistent treatment of rotation, mass-dependent compression, and composition-driven modeling to accurately model protoneutron star evolution in the context of multi-messenger astrophysics.Open AccessHyperons and $Δ$'s in rotating protoneutron stars: Local properties
The structural evolution of rotating protoneutron stars encodes essential information about their observable signatures, while microscopic properties provide complementary knowledge to advance observational investigations. Using a relativistic mean-field model with density-dependent couplings that account for temperature and particle composition, we investigate rotation, neutrino-emission-driven changes in angular momentum, particle distributions, temperature profiles, and sound speed to probe the internal dynamics of protoneutron star matter. Additionally, we track the evolution of macroscopic quantities such as energy distribution and gravitational mass and establish direct links between microphysics and global evolution. Extending the framework of Phys. Rev. D 112, 023007 (2025), which focuses on the global properties of rotating protoneutron star evolution, our results reveal that protoneutron star deformation and thermal evolution are governed by angular momentum, mass, and composition. Exotic matter (hyperons and $Δ$-resonances) and rapid rotation enhance deformation leading to a reduction in core temperature, whereas slowly rotating stars like PSR J0740$+$6620 remain nearly spherical. Our predicted equatorial radii for PSR J0740$+$6620, $13.0\ \mathrm{km} < R_e < 13.5\ \mathrm{km}$, are consistent with NICER measurements. These findings constrain the EoS, requiring a self-consistent treatment of rotation, mass-dependent compression, and composition-driven modeling to accurately model protoneutron star evolution in the context of multi-messenger astrophysics. - Open Access
- 30 September 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (9) , 1-22
Constraining the generalized Tolman–Oppenheimer–Volkoff (GTOV) equation with Bayesian analysis
In this work, we constrain the values of the parameters of the Generalized Tolman–Oppenheimer–Volkoff (GTOV) equation through Bayesian inference. We use the mass and radius data from the Neutron Star Interior Composition Explorer (NICER) for PSR J0740 $$+$$ 6620 and PSR J0030 $$+$$ 0451, as well as the mass, radius, and dimensionless tidal deformability from the gravitational wave (GW) events GW190814 and GW170817. We use two distinct parameterizations of the extended non-linear Walecka model (eNLW) with and without hyperons. The GTOV employed for the study contains additional free parameters with different physical motivations. Two possible scenarios are considered in our analysis: conservative and speculative. In the first case, we take into account the most reliable neutron star (NS) data from NICER and the GW170817 event. In the second case, we consider the possibility that the compact object with a mass of $$2.54 M_{\odot }$$ in the GW190814 event is an NS. Our findings show significant improvements in the physical quantities analyzed, leading to better agreement with the observational data compared to the results obtained using the TOV equation.- 30 September 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (9) , 1-22
Open AccessConstraining the generalized Tolman–Oppenheimer–Volkoff (GTOV) equation with Bayesian analysis
In this work, we constrain the values of the parameters of the Generalized Tolman–Oppenheimer–Volkoff (GTOV) equation through Bayesian inference. We use the mass and radius data from the Neutron Star Interior Composition Explorer (NICER) for PSR J0740 $$+$$ 6620 and PSR J0030 $$+$$ 0451, as well as the mass, radius, and dimensionless tidal deformability from the gravitational wave (GW) events GW190814 and GW170817. We use two distinct parameterizations of the extended non-linear Walecka model (eNLW) with and without hyperons. The GTOV employed for the study contains additional free parameters with different physical motivations. Two possible scenarios are considered in our analysis: conservative and speculative. In the first case, we take into account the most reliable neutron star (NS) data from NICER and the GW170817 event. In the second case, we consider the possibility that the compact object with a mass of $$2.54 M_{\odot }$$ in the GW190814 event is an NS. Our findings show significant improvements in the physical quantities analyzed, leading to better agreement with the observational data compared to the results obtained using the TOV equation. - Open Access
- 20 September 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (9) , 1-13
The sound of quintessence: analogue Kiselev acoustic black holes
In this work, we demonstrate that the geometry of a spherically symmetric black hole surrounded by a Kiselev anisotropic fluid can be effectively mimicked by an experimental setup as the ones used to investigate some physical phenomena associated with acoustic black holes. Thus, we construct the metric describing Kiselev acoustic black holes by using the Gross–Pitaevskii theory and present a general analytical solution that encompasses, as particular cases, several classes of geometries associated with black holes. This unified framework allows for the description of a wide variety of analogue spacetimes, including new analogue geometries that have not been previously explored in the literature. Then, we examine the behavior of scalar field perturbations in this background by solving the massless Klein–Gordon equation. Depending on the boundary conditions between the acoustic event horizon and infinity, we obtain the quasinormal and quasibound spectra. This study opens up avenues for experimental investigation within the context of analog gravity models, by offering new possibilities to simulate and study black hole phenomena in laboratory settings.
- 20 September 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (9) , 1-13
Open AccessThe sound of quintessence: analogue Kiselev acoustic black holes
In this work, we demonstrate that the geometry of a spherically symmetric black hole surrounded by a Kiselev anisotropic fluid can be effectively mimicked by an experimental setup as the ones used to investigate some physical phenomena associated with acoustic black holes. Thus, we construct the metric describing Kiselev acoustic black holes by using the Gross–Pitaevskii theory and present a general analytical solution that encompasses, as particular cases, several classes of geometries associated with black holes. This unified framework allows for the description of a wide variety of analogue spacetimes, including new analogue geometries that have not been previously explored in the literature. Then, we examine the behavior of scalar field perturbations in this background by solving the massless Klein–Gordon equation. Depending on the boundary conditions between the acoustic event horizon and infinity, we obtain the quasinormal and quasibound spectra. This study opens up avenues for experimental investigation within the context of analog gravity models, by offering new possibilities to simulate and study black hole phenomena in laboratory settings.
- Open Access
The sound of quintessence: analogue Kiselev acoustic black holes
In this work, we demonstrate that the geometry of a spherically symmetric black hole surrounded by a Kiselev anisotropic fluid can be effectively mimicked by an experimental setup as the ones used to investigate some physical phenomena associated with acoustic black holes. Thus, we construct the metric describing Kiselev acoustic black holes by using the Gross--Pitaevskii theory and present a general analytical solution that encompasses, as particular cases, several classes of geometries associated with black holes. This unified framework allows for the description of a wide variety of analogue spacetimes, including new analogue geometries that have not been previously explored in the literature. Then, we examine the behavior of scalar field perturbations in this background by solving the massless Klein--Gordon equation. Depending on the boundary conditions between the acoustic event horizon and infinity, we obtain the quasinormal and quasibound spectra. This study opens up avenues for experimental investigation within the context of analog gravity models, by offering new possibilities to simulate and study black hole phenomena in laboratory settings.
Open AccessThe sound of quintessence: analogue Kiselev acoustic black holes
In this work, we demonstrate that the geometry of a spherically symmetric black hole surrounded by a Kiselev anisotropic fluid can be effectively mimicked by an experimental setup as the ones used to investigate some physical phenomena associated with acoustic black holes. Thus, we construct the metric describing Kiselev acoustic black holes by using the Gross--Pitaevskii theory and present a general analytical solution that encompasses, as particular cases, several classes of geometries associated with black holes. This unified framework allows for the description of a wide variety of analogue spacetimes, including new analogue geometries that have not been previously explored in the literature. Then, we examine the behavior of scalar field perturbations in this background by solving the massless Klein--Gordon equation. Depending on the boundary conditions between the acoustic event horizon and infinity, we obtain the quasinormal and quasibound spectra. This study opens up avenues for experimental investigation within the context of analog gravity models, by offering new possibilities to simulate and study black hole phenomena in laboratory settings.