Article
Multidisciplinary Sciences
Irina Dymnikova, Evgeny Galaktionov
Summary: Regular rotating electrically charged compact objects are described by nonlinear electrodynamics minimally coupled to gravity in a self-consistent way and without additional assumptions on the relation between the electromagnetic field and gravity. The electromagnetic fields obey the system of four source-free nonlinear equations for the electromagnetic tensor F-mu nu, with only two independent components due to spacetime symmetry determined by the algebraic structure of electromagnetic stress-energy tensors (p(r)=-rho). In this paper, we present, for an arbitrary gauge-invariant Lagrangian, the general regular solution and generic behavior of electromagnetic fields, including the generic features of the Lagrange dynamics, for regular rotating electrically charged black holes and electromagnetic spinning solitons.
Article
Physics, Particles & Fields
Lars Aalsma, Gary Shiu
Summary: In this paper, the authors investigate if the mild form of the Weak Gravity Conjecture applies to extremal rotating black holes. They find that the sign of the corrections to the rotating extremality bounds is non-universal and argue that the presence of a superradiant instability is important for black hole decay.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Ramin G. Daghigh, Michael D. Green
Summary: This paper derives the equations for the odd and even parity perturbations of a black hole with an electric charge within the framework of general nonlinear electrodynamics. The stability conditions in the presence of the Hodge dual of the electromagnetic field are also obtained.
Article
Astronomy & Astrophysics
Wojciech Dyba, Patryk Mach, Mikolaj Pietrzynski
Summary: We investigated stationary models of magnetized, self-gravitating disks around black holes with different prescriptions of the toroidal magnetic field. Similar to the purely hydrodynamical case, a bifurcation in the parameter space of solutions was observed with two branches corresponding to relatively light disks and disks more massive than the black hole. The existence of the latter branch can be explained by geometric properties of the spacetime. We examined the influence of the magnetic field in the disk on these effects.
Article
Astronomy & Astrophysics
Hamid R. Bakhtiarizadeh
Summary: This study presents the construction of charged rotating black string solutions in four-dimensional Einsteinian cubic gravity for the first time, providing insights into their thermodynamic properties. The solutions are found to be completely regular at the horizon and satisfy the first law of thermodynamics. It is also observed that some solutions have positive specific heat, indicating thermodynamic stability.
Article
Physics, Multidisciplinary
Sam R. Dolan, Chris Kavanagh, Barry Wardell
Summary: Perturbations of Kerr spacetime are usually studied using the Teukolsky formalism, but in certain cases, it is necessary to construct the complete metric perturbation in the Lorenz gauge. In this paper, we obtain Lorenz-gauge solutions to the perturbed field equations on Kerr-Newman-Unti-Tamburino spacetimes using solutions of the Teukolsky equations and derive completion pieces representing mass and angular momentum perturbations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
David Kubiznak, Tayebeh Tahamtan, Otakar Svitek
Summary: This paper shows how to construct slowly rotating black hole solutions coupled to nonlinear electrodynamics with electrical and magnetic charges, and discusses the characteristics of these solutions.
Article
Physics, Multidisciplinary
Balendra Pratap Singh
Summary: We analytically study the shadow of the charged rotating black hole in the presence of quintessence. The quintessential energy has a significant impact on the shape and size of the black hole shadow, resulting in a distorted dark disk. The factors affecting the black hole shadow include mass, spin, charge, quintessential field parameter, and normalization factor. Our study shows that the black hole shadow monotonically decreases and becomes more distorted with increasing charge, while keeping the spin and normalization factor constant.
Article
Astronomy & Astrophysics
C. H. Coimbra-Araujo, R. C. Anjos
Summary: This article evaluates the motion of neutral and charged test particles near a near-extremal rotating black hole in the presence of magnetic fields, using Euler-Lagrange motion equations and effective potential methods. The study focuses on characterizing the motion out of the equatorial plane and perturbations that may lead to different orbital possibilities for particles initially moving around specific orbits. The research confirms the potential for ultra-high energy cosmic rays production at the center of AGNs with a specific range of magnetic field magnitudes, particularly near rotating black holes where high center-of-mass energies can be achieved.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Physics, Particles & Fields
Marco Astorino, Adriano Vigano
Summary: In this paper, we study multi-black hole systems immersed in external gravitational field configurations in four-dimensional General Relativity. By using an infinite multipolar expansion, the conical singularities of a series of collinear static black holes are regularized. We also achieve a stationary rotating black hole system by adding independent angular momenta and NUT parameters to each source of the binary configuration. Furthermore, a charged extension of the binary black hole system at equilibrium is generated. Lastly, we demonstrate the consistent recovery of the binary Majumdar-Papapetrou solution in the vanishing external field limit.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Multidisciplinary
Kaushlendra Kumar, Olaf Lechtenfeld, Gabriel Picanco Costa
Summary: We investigated the trajectories of point charges in the background of finite-action vacuum solutions of Maxwell's equations known as knot solutions. By using the 'de Sitter method' to generate a basis of electromagnetic knots, we observed various behaviors depending on the field configuration and parameter set, including acceleration of particles to ultrarelativistic speeds, convergence of trajectories into narrow cones, and twisting and turning of trajectories in a coherent fashion.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Physics, Particles & Fields
Adel Awad, Hassan ElSayed
Summary: We use the counterterms subtraction method to calculate various thermodynamical quantities for charged rotating black holes in five-dimensional minimal gauged supergravity. The first law and Smarr's relation in the presence of a conformal anomaly are analyzed. The calculated mass, volume, and other quantities satisfy the first law and Smarr's relation when using the counterterms method.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
G. G. L. Nashed, Shinichi Nojiri
Summary: In this study, we derived a charged slowly rotating black hole solution with a dipole scalar field that is a distortion of the Kerr-Newman black hole solution. By investigating the propagation of photons near the black hole, we found that the difference between left- and right-handed polarizations is more pronounced compared to the Kerr-Newman black hole. Finally, we determined the stability condition using geodesic deviations.
Article
Mathematics, Applied
Dan Wang, Fangqi Chen, Zhifeng Hao, Marian Wiercigroch
Summary: This paper proposes a simple electromagnetic energy harvester with cubic nonlinear stiffness and studies its dynamic responses and potential power harvest. The results show that introducing nonlinearity can increase power output and expand frequency bands and parameter regions for more power harvest.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Physics, Particles & Fields
Wen-Di Guo, Shao-Wen Wei, Yu-Xiao Liu
Summary: Seeking singularity free solutions are crucial for understanding black holes in the quantum level. A recent study successfully constructed a five-dimensional singularity free black hole/topological star. Through Kaluza-Klein reduction, a four-dimensional static spherically symmetric charged black hole with scalar hair was obtained. The shadow of this charged black hole with scalar hair was investigated for four types of observers, and it was found that the shadow size depends on the motion status of the observer and the plasma model.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Multidisciplinary
Kh Jafarzade, J. Sadeghi, B. Eslam Panah, S. H. Hendi
Summary: Investigated the thermodynamic behavior of accelerating black holes using two methods, examining the effects of free parameters and constraints on phase transitions and thermal stability. Found consistency in results between geometrical thermodynamic method, heat capacity, and P-V diagram in the extended phase space analysis.
Article
Astronomy & Astrophysics
S. H. Hendi, E. Rahimi, Z. Armanfard, Z. Owjifard
Summary: In this paper, we investigate new Lifshitz-like black hole solutions in three and four dimensions under the context of a special class of F(R) gravity in gravity's rainbow. We study the geometric and thermodynamic properties of these solutions in the extended phase space and examine the first law of thermodynamics. Additionally, we calculate the heat capacity to analyze thermal stability and potential phase transitions. Our findings indicate that the Lifshitz-like black holes in three dimensions are thermally stable, while the four-dimensional black hole solutions undergo a van der Waals-like phase transition.
Article
Physics, Multidisciplinary
S. N. Sajadi, Leila Shahkarami, Farid Charmchi, S. H. Hendi
Summary: In this paper, the Einsteinian quartic gravity minimally coupled to electrodynamics in four dimensions is studied. The field equations and a nonlinear third-order differential equation for the metric and electromagnetic potential are obtained. The conditions for the existence of charged black holes in the context of the Maxwell field are discussed. The thermodynamics and stability of the solutions are demonstrated, and it is shown that the charged black hole solutions in EQG differ from those in GR.
Article
Physics, Particles & Fields
S. N. Sajadi, S. H. Hendi
Summary: In this study, an analytical approximate rotating black hole solution for quadratic gravity (QG) is obtained by constructing near-horizon and asymptotic solutions and using a continued fraction method. The thermodynamics of the black hole solution is investigated by checking the first law of thermodynamics and the Smarr formula. Various physical properties of the solution, including its photon sphere and shadow, are also investigated.
Article
Physics, Particles & Fields
S. Mahmoudi, Kh. Jafarzade, S. H. Hendi
Summary: Inspired by Lifshitz gravity, this study proposes a new metric model that describes the anisotropic scaling behavior of spacetime. By investigating the analytical solutions of Gauss-Bonnet gravity in this geometric background, it is found that exact vacuum solutions and other solutions can be obtained by adjusting the constants properly. The geometrical properties, thermodynamic properties, and stability of the obtained solutions are also examined.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Multidisciplinary
S. H. Hendi, S. Hajkhalili, S. Mahmoudi
Summary: A new model of regular black hole in 2+1 dimensions is proposed by considering an appropriate matter field as the energy-momentum tensor. The model introduces an upper bound on the radius of the event horizon and a lower bound on the mass, motivated by astrophysical black holes. The solutions obtained are investigated for their geometric properties and found to be thermally stable in the mentioned admissible domain.
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS
(2023)
Article
Astronomy & Astrophysics
S. H. Hendi, Kh Jafarzade, B. Eslam Panah
Summary: The recent observations of M87* by the EHT have sparked interest in studying the shadow of black holes, as well as investigating the time evolution and lifetime of black holes to refine theoretical models in gravitating systems. In this study, we focus on the optical features of a charged AdS black hole in dRGT massive gravity, such as its shadow geometrical shape and energy emission rate, to narrow down the free parameters of the theory. Our main goal is to compare the rotating counterpart of the static black hole solution in dRGT massive gravity with EHT data to determine the allowed regions of the model parameters. Additionally, we analyze how the rotation factor and other parameters impact the emission of particles around the black holes.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Physics, Multidisciplinary
Kh Jafarzade, E. Rezaei, S. H. Hendi
Summary: This article investigates the geometric properties, optical features, and thermodynamic behavior of a class of rotating Lifshitz-like black hole solutions in Horava-Lifshitz gravity. Examinations on the impact of electric charge, angular momentum, and exponents on the optical characteristics and thermodynamics are conducted, including the existence of a van der Waals-like phase transition. A holographic heat engine is also constructed to study the efficiency of the black hole. The second law of thermodynamics is examined by comparing the efficiency of the black hole heat engine with the Carnot heat engine efficiency.
PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS
(2023)
Article
Astronomy & Astrophysics
S. H. Hendi, A. Nemati
Summary: In this paper, the Einstein-massive gravity coupled to the Yang-Mills gauge field in five dimensions is studied. The thermodynamic behavior of the static solutions with planar horizon geometry in the extended phase space is explored, and the validity of the first law of thermodynamics is examined using the Hessian matrix. A van der Waals like phase transition is observed for this kind of solution, despite the planar topology of the boundary. The critical quantities and the effects of the massive and Yang-Mills parameters on them are determined. Additionally, the details of the first order phase transition such as the swallow-tail behavior of the Gibbs free energy and divergencies of the specific heat are discussed.
Article
Physics, Particles & Fields
S. N. Sajadi, Ali Hajilou, S. H. Hendi
Summary: In this paper, analytical approximate black hole solutions are derived in the framework of f (R) gravity without a cosmological constant. The equations of motion are applied to a spherically symmetric spacetime with one unknown function, resulting in black hole solutions that are not constrained by the Ricci scalar. Near horizon and asymptotic solutions are obtained and combined using a continued-fraction expansion to yield a complete solution. The stability of the solutions is then investigated through the use of thermodynamics and quasi-normal modes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Particles & Fields
S. N. Sajadi, S. H. Hendi
Summary: This work introduces analytical approximate black hole solutions in Einstein-Cubic gravity. The near horizon and asymptotic solutions are constructed as the first step to obtain complete solutions. The approximate analytic solutions are then obtained through continued-fraction expansion. The thermodynamic quantities are also computed, and the analytic solutions for near horizon quantities are obtained using the first law and Smarr formula. Finally, the same approach is used to obtain new static black hole solutions with different metric functions.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Hajar Noshad, Seyed Hossein Hendi, Behzad Eslam Panah
Summary: This paper investigates the structural properties of neutron stars in the context of general relativity and mimetic gravity, and finds that the appropriate equation of states can be found in the framework of mimetic gravity to support observational data. It also shows that the results of relativistic mean-field-based models are in better agreement with observational data than non-relativistic models.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Houcine Aounallah, Behnam Pourhassan, Seyed Hossein Hendi, Mir Faizal
Summary: This paper analyzes a five-dimensional Yang-Mills black hole solution in massive gravity's rainbow, investigates the flow of such a solution with scale, discusses the scale dependence of the thermodynamics for this black hole, studies the criticality in the extended phase space treating the cosmological constant as the thermodynamics pressure, and uses the partition function to obtain corrections to the thermodynamics of this system and examine their key role in the behavior of corrected solutions.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Ali Dehghani, Seyed Hossein Hendi
Summary: In the discussion of holographic phase transitions of charged topological black holes in the context of black hole chemistry, different behaviors are observed in various dimensions, including van der Waals behavior, typical reentrant phase transition, as well as anomalous vdW and triple point phenomena.
Article
Astronomy & Astrophysics
S. H. Hendi, Kh Jafarzade
Summary: The study explores the influence of the cosmological constant on the thermodynamic behavior in black hole physics, revealing similarities between black hole phase transitions and liquid/gas phase transitions in van der Waals fluid. Additionally, the research delves into related behaviors in the non-extended phase space.
