Matter accretion and greybody factor of charged bumblebee gravity black hole

Dirac quasinormal modes of charged black holes in f(R, T) gravity with nonlinear electrodynamics

Abstract With an intent to study the combined effect of Born–Infeld field as a nonlinear electrodynamics (BI-NED) and perfect fluid dark matter (PFDM) to Einstein- $$\Lambda $$ Λ theory of gravity, we obtain the exact charged AdS black hole solutions. Next, we study the effects of the parameters of PFDM and BI on the event horizon of these black holes. Then, we compute the conserved and thermodynamical quantities and evaluate that these thermodynamical quantities can satisfy the first law of thermodynamics. In addition, we investigate thermal stability conditions for these black hole solutions in context of canonical ensemble by using the heat capacity and the Helmholtz free energy. We study the effects of the parameters of PFDM and BI-NED on the local and global stability areas. Next, we extend our study to investigate thermodynamical properties of BI-NED AdS black holes surrounded by PFDM in extended phase space by considering the cosmological constant as a thermodynamics pressure. We, obtain the conserved and thermodynamic quantities which can satisfy the first law of thermodynamics in extended phase space. We then perform a rigorous analytical verification of the Ehrenfest equations to determine whether the critical behavior of the charged BI-NED AdS black holes surrounded by PFDM corresponds to a second-order phase transition. Our findings indicate that both Ehrenfest relations are satisfied, confirming that the black hole system undergoes a second-order phase transition at the critical point. we obtain heat engines corresponding to these black holes. The goal is to see how black holes’ parameters such as parameters of PFDM and BI-NED would affect efficiency of the heat engines. Finally, we study the geodesic structure of the spacetime by analyzing both timelike and null geodesics. The effective potential is examined to determine the conditions for stable and unstable circular orbits, as well as the behavior of the innermost stable circular orbit and the photon sphere. We show that the PFDM parameter significantly modifies the orbital structure and potential barrier, while the Born–Infeld parameter produces comparatively weaker corrections. The existence of bound, critical, and unstable trajectories highlights the dynamical impact of dark matter and nonlinear electrodynamics on particle and photon motion around the black hole.

Trajectories and high frequencies spectra around charged black holes under anisotropic matter field

Analyzing thermodynamic stability of charged AdS black holes via Lyapunov exponent

Chaos bounds or violation? Fate of charged AdS black holes

Zoom-whirl orbital dynamics and Kludge gravitational waveforms in extreme mass-ratio inspirals near charged black holes surrounded by perfect fluid dark matter

Abstract In this analysis, we investigate the polarization radiation imaging of Kerr–Newman black holes, with a particular focus on the impact of black hole charge on photon propagation and polarization characteristics. By extending the traditional Walker–Penrose method, which is limited by its reliance on specific symmetric structures and Killing tensors, we overcome these limitations by constructing an ordinary differential equations (ODEs) numerical framework that combines the photon orbit equation with the polarization parallel transport equation. This allows for the self-consistent evolution of photon trajectories and polarization states in any spacetime backgrounds without relying on specific symmetries. Using this framework, we analyze the effects of black hole spin and charge on the polarization characteristics of radiation from both prograde and retrograde accretion disks. Our results show that black hole charge can significantly modify photon trajectories and polarization patterns: increasing charge compresses and distorts the EVPA structure on photon-ring scales, inducing localized rotations and asymmetries that may provide a potential diagnostic of a nonzero black hole charge.

Abstract We study the phase transition and critical phenomenon of charged black holes in Einstein–Maxwell-scalar (EMs) theory. Through comprehensive analysis of thermodynamic behaviors manifested in $$P-V$$ P - V diagrams, G ( T , P ) surfaces, and $$C_P$$ C P curves, we establish that these black holes exhibit van der Waals-type phase transition behavior. The derived critical exponents governing the phase transition show precise correspondence with both van der Waals gas-liquid systems, reinforcing the connection between black hole thermodynamics and mean field theory statistics. The findings reveal a crucial dependence of phase transition properties on the scalar charge parameter. A critical threshold emerges where phase transitions become prohibited when scalar charge exceeds a specific magnitude. However, the transition persists asymptotically as scalar charge approaches zero. The analysis further demonstrates nonlinear relationships between scalar charge and critical parameters: while small scalar charges induce increasing critical volume with charge magnitude, larger values produce an inverse trend. Critical temperature displays complementary behavior, maintaining monotonic variation under certain conditions while exhibiting inverse correlation with critical volume in others. Significantly, the transition points governing critical volume and temperature trends occur at distinct scalar charge values for different black holes, indicating a non-trivial parameter dependence. These results highlight the scalar charge’s dual role as both an enabler and suppressor of phase transitions in EMs black holes, providing new insights into the interplay between geometric configurations and thermodynamic properties in general relativity with non-minimally coupled Maxwell field.

We consider the behavior of the analogue of the Lemaître time when a particle approaches the horizon of a rotating black hole. For the Kerr metric, the aforementioned time coincides with the Doran or Natario time but we consider a more general class of metrics. We scrutiny relationship between (i) its .niteness or divergence, (ii) the forward-in-time condition, (iii) the sign of a generalized momentum/energy, (iv) the validity of the principle of kinematic censorship. The latter notion means impossibility to release in any event an energy which is literally in.nite. As a consequence, we obtain a new explanation, why collisions of two particles inside the horizon do not lead to in.nite energy in their center of mass frame. The same results are also obtained for the Reissner-Nordström metric.

Exploring the effect of inverse electrodynamics on charged black holes through oscillatory motion and collisions

The investigation of gravity in higher-dimensional spacetime has transitioned from a mathematical curiosity to a fundamental framework in theoretical physics, catalyzed by the dimensional requirements of String theory and M-theory. In this paper, we explicitly construct a spherically symmetric charged black hole solution in D ≥ 5 dimensions within a gravity theory featuring an infinite tower of higher-curvature corrections. For a given mass and electric charge, the model admits a unique static spherically symmetric solution. We demonstrate that, with an appropriate choice of coupling coefficients αn , the central singularity is progressively mitigated as the correction order increases, ultimately resolving into a globally regular spacetime in the limit of infinite-order corrections. Furthermore, the criteria for the existence of extremal black holes are determined.

Weak gravitational lensing by charged black holes in STVG: Constraints from the Sloan Lens ACS Survey

Thermodynamic supercriticality and complex phase diagram for charged Gauss-Bonnet AdS black holes

Charged nutty black holes are hairy

Thermal fluctuation and tidal force of scalar tensor–vector gravity charged black hole

Abstract In this work, we studied the Ayon-Beato Garcia (ABG) solution describing a nonsingular charged black hole using the moving-puncture method. As the first step, we obtained the BG solution in isotropic coordinates with a new, accurate numerical procedure. By focusing on the situation where there is at least one horizon, where the charge is smaller than or equal to a particular critical value, we show the transition between the wormhole geometry described by the isotropic solution to a time-independent trumpet foliation resulting from the disconnection of the two asymptotic regions of the wormhole geometry. The numerical experiments indicate that, as the charge approaches its critical value, the trumpet geometry approaches the extreme isotropic solution.

This paper primarily investigates the optical properties of two minimal deformations of the Schwarzschild black hole—the Kazakov-Solodukhin and Ghosh-Kumar black holes—under different accretion models. The event horizon, photon sphere, and critical impact parameter of the former increase relative to the Schwarzschild case, whereas those of the latter decrease. Data from the Event Horizon Telescope Collaboration are used to constrain the parameter ranges of the two black holes. Under spherical accretion, the quantum correction of the Kazakov-Solodukhin black hole enlarges the black hole shadow and reduces the integrated intensity, while the shadow of the magnetically charged Ghosh-Kumar black hole shrinks and the integrated intensity increases. The black hole’s shadow radius is independent of the choice of spherical accretion model. For an optically and geometrically thin accretion disk, the integrated intensity is dominated by direct emission, with photon-ring and lensed-ring contributions being negligible. In addition, the photon and lensed rings of the Kazakov-Solodukhin black hole are narrower, whereas those of the Ghosh-Kumar black hole are broader. Whereas the Kazakov-Solodukhin black hole is brighter, the Ghosh-Kumar black hole is dimmer. Additionally, bringing the disk closer to the black hole yields a smaller shadow radius. This paper proposes a method to distinguish different black holes within a specific thin-disk model.

Abstract This work investigates curvature-induced modifications to the Yukawa potential in static, spherically symmetric spacetimes described by Tolman metrics, focusing on their implications for compact stellar objects, with particular application to solutions IV and VI. Motivated by the interplay of quantum interactions and strong gravitational fields in systems like neutron stars, we derive explicit corrections to the Yukawa potential for these metrics based on recent work. Revisiting the previous result, contrary to what was found, that curvature corrections break the interacting potential radial symmetry near a highly charged black hole, we show that Tolman metric corrections still provide the same symmetry in the local inertial frame. Numerical estimates for astrophysical objects reveal energy shifts of the order of 10 − 34 MeV for the solution IV. The Tolman VI solution, while singular at the center, yields comparable corrections for most of the fluid sphere radius. A detailed analysis of the repulsive or attractive feature of the curvature corrections for a local observer is done for each scenario. Despite providing small corrections, these results highlight the role of spacetime geometry in shaping quantum interactions and provide a foundation for future studies of nuclear interactions within the context of relativistic stars.

In this study, we investigate the influence of the parameters of ModMax nonlinear electrodynamics and perfect-fluid dark matter (PFDM) on the geometry and physical properties of charged black holes. A static, spherically symmetric solution to the Einstein field equations describing a charged ModMax black hole immersed in a PFDM background is obtained. The motion of charged test particles in this spacetime is analyzed in detail, including the effective potential, the conditions for stable and unstable circular orbits, and the radius of the innermost stable circular orbit (ISCO). It is shown that the ModMax parameter γ shifts the orbits outward for repulsive Coulomb interactions and inward for attractive forces, while increasing PFDM enhances gravitational attraction, shifting the ISCO inward. Furthermore, the interactions and collisions of charged particles near the event horizon are examined. The center-of-mass energy exhibits the characteristic behavior in charged-particle collisions, rapidly increasing as the particles approach the horizon. The parameter γ amplifies the BSW acceleration mechanism, while α suppresses it. The electric Penrose process for charged particles is also examined, revealing that the efficiency of energy extraction increases with the black hole charge and is strongly influenced by the interaction parameter γ, which plays a dominant role in enhancing the efficiency, whereas the effect of α remains comparatively negligible.