arXiv subjects

Riasat Ali

Publications and source records attributed to Riasat Ali.

At least 19 recordsLinked to original sources

arXiv2026

Geometric effects of torsion on black hole ringdown and shadows in Poincar\'e gauge gravity

Spacetime torsion provides a natural extension of general relativity and may lead to black hole solutions that differ significantly from their Einsteinian counterparts. We investigate a class of Reissner-Nordstr\"om-like black holes in Poincar\'e gauge gravity, where the effective charge is generated entirely by spacetime torsion instead of an electromagnetic field. Within the physically relevant torsion sector, the spacetime exhibits a single-horizon structure, free from the inner horizons and extremal states characteristic of charged black holes. Using the sixth-order Wentzel-Kramers-Brillouin (WKB) approximation, Leaver's continued-fraction method, and the eikonal correspondence between quasinormal modes and unstable null geodesics, we study scalar perturbations and spin-2 test fields on the torsion-modified background. We find that increasing torsion decreases both the oscillation frequencies and damping rates, leading to longer-lived ringdown signals. We further compare the model predictions with Event Horizon Telescope observations of Sgr A* and M87*, along with representative LIGO-Virgo-KAGRA (LVK) ringdown scales, to derive constraints on the torsion parameter via a profile-$\chi^{2}$ analysis supplemented by Monte Carlo sampling. Although the resulting bounds remain consistent with the Schwarzschild limit within current observational uncertainties, our results show that spacetime torsion leaves correlated imprints on both black hole shadows and ringdown observables.

gr-qc↗

arXiv2025

Physical constraints on the Maldacena-Shenker-Stanford chaos-bound in black hole spacetimes

Chaotic motion near black holes has recently been examined through the lens of the Maldacena-Shenker-Stanford (MSS) chaos-bound, but reported violations remain contradictory. A significant source of ambiguity stems from treating the particle angular momentum as an independently adjustable parameter instead of as a quantity fixed by the circular-orbit conditions. We develop a constrained framework in which the angular momentum is determined self-consistently from the geometry. Applied to the charged Kiselev black hole, this framework shows that certain previously reported violations of the chaos bound can be attributed to inconsistent parameter choices rather than to intrinsic curvature effects. By extending the analysis to geometries containing higher-order curvature terms, we find genuine chaos-bound violations at large charge-to-mass ratios, originating from curvature corrections rather than orbital parameters. Our approach, therefore, provides a systematic means to distinguish between parameter-induced (apparent) and curvature-induced (physical) violations in Einstein gravity and its extensions.

hep-th↗

arXiv2025

First-order correction of tunneling and entropy in the Horndeski gravity-like hairy black hole

In this work, we apply tunneling formalism to analyze charged particles tunneling across a hairy black hole horizon. Such black hole solutions are essential for frameworks based on Horndeski's gravity theory. Applying a semi-classical technique, we examine the tunneling of charged particles from a hairy black hole and derive the generic tunneling spectrum of released particles, ignoring self-gravitational and interaction. It is studied to ignore the back-reaction impact of the radiated particle on the hairy black hole. We analyze the properties of the black hole, such as temperature and entropy, under the influence of quantum gravity and also observe that the first-order correction is present. We study tunneling radiation produced by a charged field equation in the presence of a generalized uncertainty effect. We modify the semi-classical technique by using the generalized uncertainty principle, the WKB approximation, and surface gravity.

gr-qc↗

arXiv2025

Evaluation of physical properties of Kiselev like AdS spacetime in the context of $f(R,~T)$ gravity under the impact of quantum gravity

The developments of the $f(R,~T)$ gravity theory, which is a logical expansion of general relativity according to Einstein, inspire us to examine this theory in greater detail and take up our study to obtain a modification of the Kiselev-like AdS black holes scenario. In this study, we employ the semi-classical Hamilton-Jacobi procedure to investigate the Hawking temperature $(T_{H})$ for 4-dimensional Kiselev-like AdS BHs in the context of $f(R,~T)$ gravity. We derive the temperature using a standard formula for Kiselev-like AdS BHs in the context of $f(R,~T)$ gravity. The relativistic field equation in the context of the generalized uncertainty principle (GUP), the semi-classical Hamilton-Jacobi procedure, and the WKB strategy are used to tunnel boson particles into the horizon under the effect of quantum gravity as well as Hawking temperature and also use this temperature to compute entropy corrections. Further, we study the $f(R,~T)$ gravity ($\zeta$), quantum gravity ($\alpha$), and particle kinetic energy ($\Xi$) effect on both temperature and entropy.

gr-qc↗

arXiv2025

Study of light deflection and shadow from a hairy black hole under the influence of the non-magnetic plasma

This article computes the bending angle of a hairy black hole at weak field limits. The Gauss-Bonnet theorem is applied to the Gaussian optical curvature; this gives a way to calculate the hairy black hole light bending angle using the Gibbons and Werner approach. We determine the light's deflection angle under the influence of gravitational decoupling parameters, non-magnetic plasma, and dark matter. Further, using the ray tracing phenomenon, we determine the shadow at which light is deflected when a non-magnetic plasma medium is present. There must exist unstable circular light orbits that can act as limit curves for light rays in a spiral motion. In this manner, the shadow can be calculated for an observer at any distance from the center, and the energy emission rate for the hairy black hole can be studied.

gr-qc↗

arXiv2024

Exploring light deflection and black hole shadows in Rastall theory with plasma effects

In this article, we examine the gravitational deflection of particles in curved spacetime immersed in perfect fluid in the context of Rastall theory. We propose an infinite region approach to Gibbons-Werner to avoid singularity, given that the integral region is generally infinite. In the Rastall theory framework, the black hole solutions in the dust field are studied. Additionally, we check the deflection angle from this spacetime under the influence of plasma. Furthermore, we analytically compute plasma's impact on a black hole shadow using a ray-tracing approach and Hamiltonian equation. Hence, the light ray motion equations are independent of the plasma's velocity. It is assumed that plasma is a dispersive medium, pressureless and non-magnetised, and the plasma particle density corresponds to particle accumulation. The supermassive black hole's shadow and emitted energy are explored when plasma falls radially from infinity onto the black hole.

gr-qc↗

arXiv2023

Tunneling and entropy analysis of parameterized black hole with rotating case

In this work, we study the parameterized black hole solution by applying the Newman-Janis approach and also examine the Hawking temperature. We consider a Lagrangian field equation associated with the generalized uncertainty principle to study the motion of boson particles. By using semi-classical phenomenon, we analyze the modified Hawking temperature and graphically check the effects of deformation, rotation and correction parameter on black hole geometry. Furthermore, we investigate the logarithmic corrected entropy and also analyze the graphical behavior of deformation and quantum gravity parameter on the logarithmic corrected entropy of black hole.

gr-qc↗

arXiv2023

Deflection angle evolution with plasma medium and without plasma medium in a parameterized black hole

\begin{abstract} Using the Keeton and Petters approach, we determine the deflection angle. We also investigate the motion of photons around a parameterized black hole in the presence of non-magnetized cold plasma by using a new ray-tracing algorithm. In spherically symmetric spacetime, we examine the influence of the plasma by applying the Hamiltonian equation on the deflection angle as well as shadow. It is examine to derive the rays analytically from Hamilton's equation by separating the metric and the plasma frequency. We study that the presence of plasma affects the deflection angle as well as shadow for the parameterized black hole and they depend on plasma frequency. If the plasma frequency is significantly lower than the photon frequency, the photon sphere and shadow radius expressions can be linearized around the values found for space light rays. Furthermore, we have graphically analyze the behavior of shadow for distinct positions under the effects of plasma frequency as well as low density plasma medium.

gr-qc↗

arXiv2023

Study of tunneling radiation and thermal fluctuations of a gauge super gravity like black hole

The Newman-Janis technique and the semi-classical Hamilton-Jacobi approach are two distinct phenomena that we apply in this paper to examine the Hawking temperature $(T_{H})$ for $4$-dimensional gauge super gravity like black hole with rotation parameters. First, using the Newman-Janis algorithmic approach, we compute the gauge super gravity like black holes solution. We use surface gravity to derive the $T_H$ for a gauge super gravity like black hole. In order to do this, we use the Lagrangian field equation in the background of generalized uncertainty principle, semi-classical Hamilton-Jacobi approach and the WKB approximation technique. Furthermore, we investigate the stability of considered geometry with the help of corrected entropy and well known thermodynamic quantities. It is concluded that the gauge super gravity like black holes is stable under first-order corrections.

gr-qc↗

arXiv2023

Thermodynamics and logarithmic corrections of symmergent black holes

In this paper, we study quantum gravity effect on the symmergent black hole which is derived from quadratic-curvature gravity. To do so, we use the Klein-Gordon equation which is modified by generalized uncertainty principle (GUP). After solving the field equations, we examine the symmergent black hole's tunneling and Hawking temperature. We explore the graphs of the temperature through the outer horizon to check the GUP influenced conditions of symmergent black hole stability. We also explain how symmergent black holes behave physically when influenced by quantum gravity. The impacts of thermal fluctuations on the thermodynamics of a symmergent black holes spacetime are examined. We first evaluate the model under consideration's thermodynamic properties, such as its Hawking temperature, angular velocity, entropy, and electric potential. We evaluate the logarithmic correction terms for entropy around the equilibrium state in order to examine the impacts of thermal fluctuations. In the presence of these correction terms, we also examine the viability of the first law of thermodynamics. Finally, we evaluate the system's stability using the Hessian matrix and heat capacity. It is determined that a stable model is generated by logarithmic corrections arising from thermal fluctuations.

gr-qc↗

arXiv2023

Tunneling and thermodynamics evolution of the magnetized Ernst-like black hole

We investigate the tunneling phenomenon of particles through the horizon of a magnetized Ernst-like black hole. We employ the modified Lagrangian equation with the extended uncertainty principle for this black hole. We determine a tunneling rate and the related Hawking temperature for this black hole by using the WKB approach in the field equation. In addition, we examine the graph behavior of the Hawking temperature in relation to the black hole event horizon. We explore the stability analysis of this black hole by taking into account the impact of quantum gravity on Hawking temperatures. The temperature for a magnetized Ernst-like black hole rises as the correction parameter is decreased. Moreover, we analyze the thermodynamics quantities such as Hawking temperature, heat capacity and Bekenstein entropy by using the different approach. We obtain the corrected entropy to study the impact of logarithmic corrections on the different thermodynamic quantities. It is shown that these correction terms makes the system stable under thermal fluctuations.

gr-qc↗

arXiv2023

Logarithm Corrections and Thermodynamics for Horndeski gravity like Black Holes

In this paper, we compute the Hawking temperature by applying quantum tunneling approach for the Horndeski like black holes. We utilize the semi-classical phenomenon and WKB approximation to the Lagrangian field equation involving generalized uncertainty principle (GUP) and compute the tunneling rate as well as Hawking temperature. For the zero gravity parameter, we obtain results consistent without correction parameter or original tunneling. Moreover, we study the thermal fluctuations of the considered geometry and examine the stable state of the system by heat capacity technique. We also investigate the behaviour of thermodynamic quantities under the influence of thermal fluctuations. We observe from the graphical analysis, the corresponding system is thermodynamically stable with these correction terms.

gr-qc↗

arXiv2023

Tunneling analysis of null aether black hole theory in the background of Newman-Janis algorithm

We present a new asymptotically flat black hole solution in null aether theory (NAT) by applying Newman-Janis process. For this purpose, we study the asymptotically flat NAT black hole solution in Newman-Janis algorithm and then compute the tunneling radiation for NAT black hole. The Hawking temperature for NAT black hole depends upon the rotation parameter and charge of the black hole. The Hawking temperature describes a black hole with extremal event horizon. Furthermore, we analyze the graphical interpretation of Hawking temperature w.r.t event horizon and check the stability of black hole under the influence of different parameters associated with black hole temperature.

gr-qc↗

arXiv2022

Thermal Fluctuations Evolution of the New Schwarzschild Black Hole

We study the thermodynamic analysis and logarithm corrections of the new Schwarzschild black hole. We compute the thermodynamic quantities like entropy, Hawking temperature and heat capacity. The area of black holes never decreases because they absorb everything from their surroundings due to high gravity. In this regard, the area-entropy relation proposed by Bekenstein needs to be corrected, leading to the concept of logarithmic corrections. To do so, we obtain the corrected entropy for new Schwarzschild black hole to analyze the effects of thermal fluctuations and we evaluate the thermodynamic quantities like specific heat, internal energy, Helmholtz free energy, Gibbs free energy, enthalpy and pressure in the presence of correction parameter $η$. Furthermore, we check the stability of the system with the help of heat capacity and well known Hessian matrix technique. By our graphical analysis, we observe that the thermal fluctuations effects the stability of small radii black holes (e.g., New Schwarzchild black hole) and therefore, small black holes get unstable regions due to these first order corrections.

gr-qc↗

arXiv2022

Gravitational Analysis of Einstein-Non-Linear-Maxwell-Yukawa Black Hole under the Effect of Newman-Janis Algorithm

In this paper, we analyze the rotating Einstein-non-linear-Maxwell-Yukawa black hole solution by Janis-Newman algorithmic rule and complex calculations. We investigate the basic properties (i.e., Hawking radiation) for the corresponding black hole solution. From the horizon structure of the black hole, we discuss the graphical behavior of Hawking temperature $T_H$ and analyze the effects of spin parameter (appears due to Newman-Janis approach) on the $T_H$ of black hole. Furthermore, we investigate the corrected temperature for rotating Einstein-non-linear-Maxwell-Yukawa black hole by using the vector particles tunneling strategy which is based on Hamilton-Jacobi method. We additionally study the graphical explanation of corrected $T_H$ through outer horizon to investigate the physical and stable conditions of black hole. Finally, we compute the corrected entropy and check that the effect of charged, rotation and gravity on entropy.

gr-qc↗

arXiv2022

Gravitational Analysis of Rotating Charged Black Hole-Like Solution in Einstein-Gauss-Bonnet Gravity

This work analyzes the Einstein-Gauss-Bonnet gravity of charged black hole solutions through Newman-Janis approach. The Hawking temperature for corresponding black hole is also computed. The solution depends upon rotation parameter $a$, black hole mass, charge and horizon. Moreover, the graphical behavior of temperature via event horizon to analyze the stability of black hole under the effects of rotation parameter is discussed. The graphs are plotted in the presence/absence of rotation parameter and charge. Furthermore, the Hawking temperature under gravity effects is studied by using the semi-classical method. It is also observed that the maximum temperature at non-zero horizon depicts the BH remnant. Finally, the logarithmic corrected entropy for given black hole is computed and the logarithmic corrected entropy under effects of rotation and correction parameter are studied.

gr-qc↗

arXiv2022

Tunneling Analysis of Regular Black Holes with Cosmic Strings-Like Solution in Newman-Janis Algorithm

We consider the regular black holes solution with cosmic strings(RBHCS) in the rotation parameter by assuming the Newman-Janis method. After this, we study thermodynamical property (i.e., Hawking temperature $T_H$) for the RBHCS in the presence of spin parameter. Moreover, we study the graphical interpretation of Hawking temperature with event horizon to check the physical and stable form of RBHCS under the effect of Newman-Janis algorithm. We graphically show that the RBHCS in the context of Newman-Janis algorithm are colder than the Schwarzschild black hole. Furthermore, we investigate the quantum corrected temperature for RBHCS in Newman-Janis method by incorporating generalized uncertainty principle. We have also analyzed the graphical interpretation of corrected temperature $T'_{H}$ versus $r_{+}$ and study the stable condition of RBHCS in Newman-Janis method in the presence of gravity parameter effects. Finally, the corrected entropy for RBHCS with rotation parameter is analyzed.

gr-qc↗

arXiv2022

Tunneling Analysis of Kerr-Newman Black Hole-Like Solution in Rastall Theory

Hamilton-Jacobi ansatz is used to analyze boson charged particles tunneling in Rastall gravity Kerr- Newman black hole (BH) surrounded by perfect fluid matter through the horizon. The geometrical BH parameters are observed, how these are affecting the radiation utilizing the Lagrangian gravity equation. In this article, the corrected Hawking temperature is computed by considering the effects of quantum gravity. In our analysis, the Rastall gravity BH solution surround by perfect fluid matter effects on Hawking radiation is analyzed graphically. Moreover, the stability and instability of Rastall gravity BH are investigated. The influence of quantum gravity and rotation parameters on BH radiation are also observed by graphical representation.

gr-qc↗