Article
Physics, Particles & Fields
S. Habib Mazharimousavi
Summary: This article revisits the null energy condition in the context of thin-shell wormholes and introduces the general and stability conditions for satisfying this condition. Additionally, a specific metric is introduced that satisfies the null energy condition and remains stable.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Naoki Tsukamoto
Summary: The study introduces reflection-asymmetric thin-shell wormholes with double shadows, composed of parts of Schwarzschild and Reissner-Nordstrom spacetimes with two photon spheres of different sizes. The researchers discussed the observational properties of these double shadows seen from an observer's perspective, emphasizing the presence of two photon rings with varying diameters.
Article
Physics, Multidisciplinary
M. Sharif, Faisal Javed
Summary: This paper compares the stability of geometrical structures of self-gravitating charged thin-shell and thin-shell wormholes with different types of matter distributions, finding that the thin-shell is more stable than the thin-shell wormhole.
Article
Physics, Multidisciplinary
Nisha Godani
Summary: This paper explores the thin-shell wormholes constructed from the charged regular black hole solutions developed in 1999, defined by using the nonlinear electrodynamics coupled to general relativity in the gravitational action. The thin-shell wormhole solutions are studied in the framework of the quadratic f(R) gravity model with a linear and nonlinear equation of states. It is found that stable wormhole solutions satisfying energy conditions are possible for a suitable choice of parameters.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
Mohammad Reza Mehdizadeh, Amir Hadi Ziaie
Summary: This study investigates evolving wormhole configurations in third-order Lovelock gravity theory, exploring the possibility of satisfying energy conditions. The analysis reveals that for certain third-order Lovelock coefficients, there are wormhole solutions that respect the weak energy condition (WEC).
Article
Physics, Particles & Fields
Cecilia Bejarano, Ernesto F. Eiroa, Griselda Figueroa-Aguirre
Summary: This study constructs a broad family of thin-shell wormholes with circular symmetry in (2+1)-dimensional F(R) theories of gravity and investigates the stability of static configurations under perturbations preserving the symmetry. Examples of charged thin-shell wormholes are provided which are asymptotically anti-de Sitter at both sides of the throat, and it is shown that stable solutions are possible with suitable values of the parameters.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Donald Marolf, Jorge E. Santos
Summary: The study explores the construction and stability of asymptotically anti-de Sitter Euclidean wormholes in various models. It finds stable two-boundary Euclidean wormhole solutions in some models, but in UV-complete settings, the wormholes suffer from brane-nucleation instabilities despite efforts to stabilize them with large values of sources. This indicates the existence of additional disconnected solutions with lower action.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Physics, Particles & Fields
Faisal Javed, Arfa Waseem, Bander Almutairi
Summary: This manuscript examines the stable geometry of thin-shell wormholes in the framework of static, spherically-symmetric quantum corrected charged black hole solution bounded by quintessence. Thin-shell wormholes are developed from two equivalent copies of black hole solutions through the cut and paste approach, and the stability of the developed wormhole geometry is discussed using linearized radial perturbation. The presence of charge and quantum correction affects the stability of thin-shell wormholes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
A. Belhaj, Y. El Maadi, S-E Ennadifi, Y. Hassouni, M. B. Sedra
Summary: Inspired by results in particle physics, the study focuses on certain dyonic solutions in arbitrary dimensions, examining their stringy constructions and tensor network realizations through multistate particle formalism.
MODERN PHYSICS LETTERS A
(2021)
Article
Physics, Particles & Fields
Hyojoong Kim, Nakwoo Kim
Summary: In this study, the non-rotating, dyonically charged, and supersymmetric AdS(4) black holes were revisited as solutions of N = 2 gauged supergravity with vector- and hyper-multiplets. By uplifting the near horizon solutions to D = 11 supergravity, it was shown that dyonic AdS(4) black holes correspond to AdS(2) solutions with electric and magnetic baryonic fluxes in D = 11 supergravity. The entropy of dyonic black holes was calculated by carefully analyzing the Page charge quantization conditions, identifying the off-shell AdS(4) black hole solutions with parameters of D = 11 AdS(2) solutions.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Multidisciplinary
Nilofar Rahman, Mehedi Kalam, Amit Das, Sayeedul Islam, Farook Rahaman, Masum Murshid
Summary: Einstein-Gauss-Bonnet gravity is a generalization of general relativity to higher dimensions. By using the "Cut-Paste" technique from black holes in Einstein-Gauss-Bonnet gravity and inspired by non-commutative geometry, a new class of 5D thin-shell wormholes has been constructed, with a static spherically symmetric, Gaussian mass distribution as the source. The study explores the pressure-density profile, equation of state, nature of the wormhole, and the total amount of exotic matter content at the shell, as well as analyzes the linearized stability of the constructed wormhole. The findings suggest that the model is plausible compared to other thin-shell wormhole models in literature.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Stefano Andriolo, Gary Shiu, Pablo Soler, Thomas Van Riet
Summary: This study focuses on the corrections to classical axion wormhole solutions in string motivated scenarios, and finds that these corrections are consistent with the weak gravity conjecture for axions. This has important implications for the path integral of quantum gravity.
CLASSICAL AND QUANTUM GRAVITY
(2022)
Article
Physics, Particles & Fields
Liang Ma, Yi Pang, H. Lu
Summary: In this study, non-extremal dyonic string solutions were constructed in 6D minimal supergravity, with higher derivative corrections obtained from either the type IIA string theory or the heterotic string theory. It was found that the α' corrections can affect the attractive force in the isoentropic process near extremality, while not affecting the mass-to-charge ratio. On the other hand, in the isothermal or isoenergetic processes, the α' corrections can enhance the attractive force.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Multidisciplinary
M. Z. Bhatti, Z. Yousaf, M. Yousaf
Summary: In this paper, we analyze thin-shell wormholes from two identical copies of charged static cylindrically symmetric spacetimes using Visser's 'cut and paste' approach in f(R, T) gravity. We examine the stability of the wormholes under linear perturbations while considering the cylindrical symmetry and also investigate the influence of charge on their stability. The results suggest that a wormhole model with a charge may exhibit more stable behavior compared to an uncharged system.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2023)
Article
Physics, Mathematical
Nisha Godani
Summary: The charged thin-shell wormholes are constructed using the cut-and-paste approach in the f(R) theory of gravity. The stability analysis is conducted in f(R) = R + alpha R-n gravity formalism with a linear equation of state. The effect of charge and mass on the throat radius is analyzed, and the stability of the thin shell is obtained.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Physics, Mathematical
Faisal Javed, G. Fatima, G. Mustafa, Ali Ovgun
Summary: This paper investigates the stable configuration of thin-shell wormholes formed from two equivalent geometries of Reissner-Nordstrom black hole with nonlinear electrodynamics. The stability of the developed model is explored by considering different types of matter distribution located at thin-shell. It is found that the presence of nonlinear electrodynamics allows for stable regions in the Reissner-Nordstrom black hole.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Reggie C. Pantig, Ali Ovgun
Summary: In this paper, the Poincare Gauge theory of gravity is used to analyze the effects of torsion on black holes by studying the deflection angles and shadow radius. The study also explores the impact of torsion on the luminosity of the photonsphere and other properties of black holes. The findings suggest that the torsion parameter plays a significant role in these phenomena.
Article
Physics, Multidisciplinary
Reggie C. Pantig, Ali Ovgun
Summary: In this work, the researchers investigated the impact of fuzzy dark matter (FDM) or wave dark matter on a supermassive black hole (SMBH). By treating the FDM as a spherical distribution surrounding the SMBH, they obtained a new metric that combines the black hole and dark matter spacetime geometries. The study also analyzed the effects of soliton dark matter on the shadow behavior and weak deflection angle, and found considerable deviations that suggest the possible experimental detection of soliton dark matter using an SMBH at the galactic centers.
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS
(2023)
Article
Physics, Mathematical
Wajiha Javed, Mehak Atique, Reggie C. Pantig, Ali Ovgun
Summary: This paper investigates gravitational lensing in the weak field limits and shadows of charged black holes in non-linear electrodynamics corrections. The results show that the bending angle increases with the effects of mediums in vacuum and plasma, and exponentially decreases with the impact parameter u.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Amodio Carleo, Gaetano Lambiase, Ali Ovgun
Summary: Non-linear electrodynamics is a generalization of Maxwell's electrodynamics for strong fields, with significant implications for black hole and cosmology studies. Two new methods for investigating these non-linear theories are explored in this study. The Blandford-Znajek mechanism is analyzed, revealing that the emitted power can increase or decrease depending on the NLED model, and the black hole's magnetic field lines become vertical quickly. The confinement of NLED parameters by amplifying primordial magnetic fields is attempted, proving useful only in certain models.
ANNALEN DER PHYSIK
(2023)
Article
Physics, Mathematical
Abdul Jawad, Shahid Chaudhary, Muhammad Yasir, Ali Ovgun, Izzet Sakalli
Summary: In this paper, the spectrum of the quasinormal modes of Hayward black hole in Einstein-Gauss-Bonnet gravity, Hayward black hole in anti-de Sitter space (AdS) spacetime, and 4-dimensional black hole in Einstein-Lovelock gravity is evaluated. The 6th-order WKB resonance technique is used to examine the quasinormal modes frequencies ? by shifting the charge parameter Q, circular harmonic index l, and mass of scalar field m. It is observed that the 6th-order WKB method gives high accuracy when the multipole number l is larger than the overtone n. The real and imaginary components of the quasinormal modes are not linear functions, similar to Reisnner-Nordstrom-AdS. For large values of charge, the quasinormal ringing becomes slower and the frequency of the oscillation becomes smaller.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Ali Ovgun, Reggie C. Pantig, Angel Rincon
Summary: We investigate the shadow, deflection angle, and greybody bounding of a Schwarzschild-AdS/dS black hole in scale dependent gravity. We constrain the parameter epsilon using EHT data and find that it ranges at orders of magnitude of 10(-11) - 10(-16) for Sgr. A* and 10(-11) - 10(-17) for M87*. The behavior of shadow radius perceived by a static observer varies near the cosmological horizon even with the same scaling parameters for Sgr. A* and M87*. The deflection angle strongly depends on massive particles and the effect of epsilon on Sgr. A* is limited to points of low impact parameters.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Ilim Irfan cimdiker, Ali Ovgun, Durmus Demir
Summary: In this study, we investigate circular orbits, effective potential, and thin-accretion disk of a black hole in symmergent gravity (SG), using the Novikov-Thorne model and considering the energy flux and temperature distribution. We establish limits on SG parameters and conclude that the accretion disk can serve as an astrophysical tool for probing SG.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Beyhan Pulice, Reggie C. Pantig, Ali Ovgun, Durmus Demir
Summary: In this paper, the authors report on exact charged black hole solutions in symmergent gravity with a Maxwell field. They study various properties of the black holes, such as horizon formation, shadow cast, and gravitational lensing, as functions of the black hole charge. They also explore the weak field regime and discuss the potential detectability of a weak deflection angle caused by the black hole.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Wajiha Javed, Mehak Atique, Ali Ovguen
Summary: In this paper, the weak deflection angle of electric and magnetic black holes in the background of nonlinear electrodynamics is studied using the Gauss-Bonnet theorem and bounding greybody factor. The Gaussian optical curvature is obtained using the approach of Gibbons and Werner, and then used in the Gauss-Bonnet theorem to calculate the bending angle. The rigorous bounds of the greybody factor are also calculated, and the graphical behavior of bending angles and greybody bounds at specific values of parameters and black hole charges is analyzed.
Article
Physics, Particles & Fields
Dhruba Jyoti Gogoi, Ali Ovgun, M. Koussour
Summary: In this work, we studied the quasinormal modes of a black hole in f(Q) Sigma nin f(Q) gravity using the Bernstein spectral method, and validated the method with the Pade averaged higher-order WKB approximation method. We considered scalar and electromagnetic perturbations in the black hole spacetime and obtained the corresponding quasinormal modes. We found that the quasinormal frequencies in scalar perturbation are higher than those in electromagnetic perturbation for a non-vanishing nonmetricity scalar Q0. However, the damping rate of gravitational waves is higher for electromagnetic perturbation. Time domain profiles for both types of perturbations were also investigated to confirm the quasinormal mode behavior.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Particles & Fields
Gaetano Lambiase, Reggie C. Pantig, Dhruba Jyoti Gogoi, Ali Ovgun
Summary: The study investigates the relationship between the deformation parameter beta of the generalized uncertainty principle (GUP) and the two free parameters (omega) over cap and gamma of the running Newtonian coupling constant of the Asymptotic Safe gravity (ASG) program. By analyzing the shadow and quasinormal modes of black holes, the results confirm the consistency of ASG and GUP, and provide new insights into the nature of black holes and their signatures. The implications of these findings for future studies in quantum gravity are also discussed.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Particles & Fields
H. B. Benaoum, Genly Leon, A. Ovgun, H. Quevedo
Summary: This study investigates inflation driven by a nonlinear electromagnetic field based on an NLED lagrangian density. The study formulates an f-NLED cosmological model with a general function f (F) and explores two interesting examples of the function f (F). The study also analyzes the implications of NLED by studying inflationary parameters and compares the results with observational data.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Yi Yang, Dong Liu, Ali Ovgun, Zheng-Wen Long, Zhaoyi Xu
Summary: Gravitational decoupling can add hair to black holes, and we investigated the quasinormal modes of hairy black holes caused by gravitational decoupling. We derived the equations of effective potential for three perturbations in a hairy black hole spacetime and studied their time evolution. By analyzing the influence of the hairs (alpha, l0, and Q) on quasinormal modes, we found that alpha and l0 decrease the oscillation frequency of gravitational-wave signal, while Q increases it. Additionally, we calculated the bounds of the greybody factor and high-energy absorption cross section, showing that primary hair generated by charges (alpha and l0) can increase the probability of gravitational radiation reaching spatial infinity, while the charge Q from extra sources has the opposite effect.
Article
Physics, Particles & Fields
Reggie C. Pantig, Ali Ovgun, Durmus Demir
Summary: This paper investigates rotating black holes in symmergent gravity and uses deviations from the Kerr black hole to constrain the parameters. Symmergent gravity introduces the gravitational constant G and quadratic curvature coefficient c(O) from flat space-time matter loops. By studying the photon sphere, shadow size, and deflection angle, the authors find significant deviations and sensitivity of black holes to symmergent gravity effects. The analysis also reveals the influence of the distance between the source, receiver, and lensing object on the deflection angle, and the necessity of a negative c(O) for a consistent solution.
EUROPEAN PHYSICAL JOURNAL C
(2023)