Black Holes In Rastall Gravity Research Articles

Entropy correction of Kerr–Newman-AdS black hole in Rastall gravity under Lorentz symmetry violation

The tunneling of scalar particles and fermions across the event horizon of KN-AdS black hole surrounded by perfect fluid in Rastall theory are investigated in the frame dragging coordinate systems by applying modified Klein–Gordon equation and modified Dirac equation under the influence of Lorentz symmetry violation in curved spacetime. The Hawking temperature and the heat capacity of the black hole are modified due to the influence of Lorentz symmetry violation. The Hawking temperature and the Bekenstein–Hawking entropy of the black hole beyond the semiclassical approximation are also derived by taking the effects of Planck constant [Formula: see text]. The modified Hawking temperature and entropy correction of the black hole are dependent on the Lorentz violation parameter [Formula: see text], the ether-like vectors [Formula: see text] and Planck constant [Formula: see text].

Heat engine efficiency for four-dimensional charged AdS black holes in Rastall gravity

In this paper, we analyze the [Formula: see text] criticality and the heat engine efficiency of two black holes, one is the four-dimensional charged AdS black hole in Rastall gravity and the other is the four-dimensional charged AdS black hole surrounded by quintessence in Rastall gravity. For the four-dimensional charged AdS black hole in Rastall gravity, the ratio [Formula: see text] is related to the Rastall parameter [Formula: see text]. When [Formula: see text] the ratio becomes [Formula: see text], which is same as the van der Waals liquid-gas system. Additionally, as the Rastall parameter [Formula: see text] increases, the heat engine efficiency [Formula: see text] of the black hole will increase. Moreover, the efficiency [Formula: see text] decreases rapidly at first and then increases with the entropy [Formula: see text]. But the efficiency ratio [Formula: see text] decreases with the Rastall parameter [Formula: see text]. For the four-dimensional charged AdS black hole surrounded by quintessence in Rastall gravity, as the charge q increases, the critical specific volume [Formula: see text] and the efficiency ratio [Formula: see text] also increase, however, the critical temperature [Formula: see text] and the critical pressure [Formula: see text] gradually decrease. Moreover, the heat engine efficiency [Formula: see text] and the efficiency ratio [Formula: see text] of the black hole are similar to the four-dimensional charged AdS black hole in Rastall gravity.

Phase structures and critical behavior of rational non-linear electrodynamics Anti de Sitter black holes in Rastall gravity

This research paper presents a black hole solution with a rational nonlinear electrodynamics source within the Rastall gravity framework. The paper analyzes the thermodynamic properties of the solution in normal phase space and explores its critical behavior. The phase structure is examined using the extended first law of thermodynamics, with the cosmological constant Λ serving as pressure P. The isotherms exhibit van der Waals behavior at small values of horizon r +. The paper also investigates the Gibbs free energy behavior and finds two critical points with two pressures where the re-entrant phase transition occurs and disappears. We also explore the prevalent microstructure of black holes in Ruppeiner geometry, uncovering significant deviations in the nature of particle interactions from conventional practice. Moreover, the thermodynamic geometry is analyzed using the Ruppeiner formalism, with the normalized Ricci scalar indicating possible point-phase transitions of the heat capacity, and the normalized extrinsic curvature having the same sign as the normalized Ricci scalar. The three-phase transitions of the heat capacity are those that we find for the normalized Ruppeiner curvatures. Thus, there is an absolute correspondence.

Interior volume of power-Maxwell charged black hole in Rastall gravity

In this work, we try to find the volume inside the power-Maxwell charged black hole in Rastall gravity based on the definition and method proposed by Christodoulou and Rovelli. We find the interior volume as well as CR volume for this black hole. We also analyze our work numerically and show that our result is compatible with previous results obtained by various authors.

Thermodynamic stability and holographic heat engine efficiency of a Kerr–Newmann-NUT-Kiselev-AdS black hole in Rastall gravity

Einstein’s general relativity was modified to the Rastall gravity by generalizing the energy–momentum conservation law to T;μμν=λRν and for this change in the covariant conservation of Tμν the thermodynamic characteristics also show some interesting properties. Here we discuss the thermodynamics, phase transition, stability and heat engine construction of a Kerr–Newman-NUT-Kiselev-AdS black hole in 4D Rastall gravity. We consider the space to be surrounded by dark energy, a specific perfect fluid matter. The dark energy has significant effects on the thermodynamic variables of the black hole. Here, the energy condition constraints the Rastall parameter (λ). We finally find that the equation-of-state is related to the Rastall parameter (λ) even when it is reduced to the critical point. The cosmological constant leads us to consider the black hole as a heat engine and determine the efficiency of the Carnot cycle for the black hole. In conclusion, we discuss possible methodologies for constraining the black hole parameters from astrophysical observations.

Joule‐Thomson Expansion and Optical Behaviour of Reissner‐Nordström‐Anti‐de Sitter Black Holes in Rastall Gravity Surrounded by a Quintessence Field

AbstractThis paper deals with the thermodynamics, Joule‐Thomson expansion and optical behaviour of a Reissner‐Nordström‐anti‐de Sitter black hole in Rastall gravity surrounded by a quintessence field. The black hole solution obtained in this framework is different from a corresponding black hole in General Relativity. The black hole metric function, as well as the Hawking temperature, is affected by the presence of energy‐momentum conservation violation. The presence of energy‐momentum conservation violation also affects the isenthalpic and inversion temperature curves, and with an increase in the Rastall parameter, the inversion temperature rises slowly. The impacts of other parameters, such as charge, structural constant etc., are investigated and compared. The black hole shadow, as well as the energy emission rate of the black hole, decreases with an increase in the Rastall parameter. Hence, the black holes evaporate slowly in presence of energy‐momentum conservation violation.

Quasinormal oscillations and late-time tail of massless scalar perturbations of a magnetized black hole in Rastall gravity* *Supported by the National Natural Science Foundation of China (NNSFC) (11805166, 11925503, 12175076). We also gratefully acknowledge the financial support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro

In this study, we investigate the quasinormal mode and late-time tail of charged massless scalar perturbations of a black hole in generalized Rastall gravity. The black hole metric in question is spherically symmetric, accompanied by a power-Maxwell field surrounded by a quintessence fluid. We show that the massless scalar field, when dressed up with the magnetic field, acquires an effective mass, which significantly affects the properties of the resultant quasinormal oscillations and late-time tails. Specifically, the quasinormal frequencies become distorted and might even be unstable for particular spacetime configurations. Additionally, the exponent of the usual power-law tail is modified according to the modification in the structure of the branch cut of the retarded Green's function. In particular, as the effective mass is generated dynamically owing to the presence of the magnetic field, we may consider a process through which the field is gradually removed from the spacetime configuration. In this context, while the quasinormal oscillations converge to the case of massless perturbations, we argue that the properties of resultant late-time tails do not fall back to their massless counterpart. The relevant characteristics are investigated using numerical and analytic approaches.

Gravitational lensing for power-Maxwell charged quintessence black hole in Rastall gravity

In this paper, we investigate the gravitational lensing for power-Maxwell charged quintessence black hole (BH) without cosmological constant in Rastall’s theory of gravity in both the strong-field limit and weak-field limit. Furthermore, we discuss the gravitational lensing by the linear electrodynamic (LE) and nonlinear electrodynamic (NLE) Maxwell field with the equation of state (EoS) parameter of the quintessence ([Formula: see text]) and compared to the case with Einstein’s gravity. We discuss the behaviors of the photon sphere radius [Formula: see text], impact parameter [Formula: see text], strong lensing coefficients [Formula: see text], [Formula: see text] and the deflection angle [Formula: see text] on the equatorial plane [Formula: see text] with the different values of Rastall parameter [Formula: see text] for the case of LE and NLE Maxwell field in the strong field limit. We also investigate the angular separation [Formula: see text], angular position [Formula: see text] and the magnification of the relativistic images. Further, we also study about the weak lensing BHs in Rastall gravity. We investigate the behaviors of weak deflection angle with the different values of Rastall parameter [Formula: see text] for the case of LE and NLE Maxwell field in the weak-field limit.

Thermodynamic Stability and Holographic Heat Engine Efficiency of a Kerr-Newmann-Nut-Kiselev-Ads Blackhole in Rastall Gravity

Thermodynamic Stability and Holographic Heat Engine Efficiency of a Kerr-Newmann-Nut-Kiselev-Ads Blackhole in Rastall Gravity

Dynamics and fundamental frequencies of test particles orbiting Kerr–Newman–NUT–Kiselev black hole in Rastall gravity

The spacetime properties in the exterior of the Kerr–Newman–NUT–Kiselev black hole in the Rastall theory of gravity, through particle dynamics, are investigated with the aim to find possible degeneracy of the different black hole parameters. We show that the effective potential, the energy, and the angular momentum of a test particle moving in the spacetime of such a black hole strongly depend on the central black hole parameters. We also evaluate the innermost stable circular orbit radii of test particles and show how the spacetime parameters can act on them. Further, we show the results for the fundamental frequencies of test particles moving at small distances from the circular orbits in the equatorial plane. We demonstrate that change in the Rastall parameter $$\kappa \lambda $$ can make the radial epicyclic frequency to become zero at larger distances from the central source. We also notice that for the vertical epicyclic frequencies, in the case of the Kerr–Newman–NUT–Kiselev black hole in the Rastall theory of gravity lower frequencies, are observed as compared to the frequencies observed in the case of the Kerr black hole. Finally, we show that for the Kerr–Newman–NUT–Kiselev black hole in the Rastall gravity, the Keplerian frequencies are almost identical with the frequencies noticed in the case of the Kerr black hole and the difference between the two can only be observed in the regions in a very close vicinity to the central black hole, studied in the present work.

Quasinormal modes of black holes with non-linear-electrodynamic sources in Rastall gravity

One of the notable modifications of General Relativity (GR) is the Rastall gravity. We have studied the polarization modes of Gravitational Waves (GWs) in this gravity. It is found that at a very far distance away from the source of GWs, Rastall gravity behaves identically to GR. That is, we get only two massless tensor polarization modes of GWs in the theory. Afterwards, we have extended our study to quasinormal modes of black holes in Rastall gravity in presence of non-linear electrodynamic sources. Here the impacts of cosmological field, dust field, phantom field, quintessence field and radiation field on the quasinormal modes in presence of electrodynamic sources have been investigated. Apart from this, we have also checked the dependency of quasinormal modes with the Rastall parameter $\lambda$, black hole structural constant $N_s$ and charge of the black hole $Q$. The study shows that the quasinormal modes corresponding to the black hole with non-linear electrodynamic sources show significant deviations from a general charged black hole in Rastall gravity under certain conditions. Further, the behaviour of black holes and hence the quasinormal modes depend on the type of surrounding field considered.

The shadow and photon sphere of the charged black hole in Rastall gravity

Considering a charged black hole (BH) surrounded by a perfect fluid radiation field (PFRF) in Rastall gravity, we investigate this BH shadow and photon sphere on different spherical accretions backgrounds. The effect of the PFRF parameter/BH charge on the critical impact parameter is studied by investigating the light deflection near this BH. The luminosity of these BH shadows in different spherical accretions is obtained, respectively. It is found that the shadow of this BH with infalling spherical accretion is darker than static spherical accretion, and the photon sphere with infalling spherical accretion is brighter than a static one. We creatively investigate the effects of the BH charge/PFRF parameter on the luminosity of BH shadow and photon sphere. The results implying that the BH shadow is a signature of space-time geometry, and the photon sphere luminosity is affected by accretion materials and BH itself.

Gravitational analysis of neutral regular black hole in Rastall gravity

This paper is devoted to the tunneling radiation and quantum gravity effect on tunneling radiation of neutral regular black hole in Rastall gravity. We analyzed the tunneling radiation and Hawking temperature of neutral regular black hole by applying the Hamilton-Jacobi ansatz phenomenon. Lagrangian wave equation have been investigated by generalized uncertainty principle (GUP), using the WKB-approximation and calculated the tunneling rate as well as temperature. Furthermore, we analyzed the temperature of this neutral regular black hole in the presence of gravity. The stability and instability of neutral regular black hole are also analyzed.

Dirac quasinormal modes of power-Maxwell charged black holes in Rastall gravity

In this paper, we study the quasinormal modes of the massless Dirac field for charged black holes in Rastall gravity. The spherically symmetric black hole solutions in question are characterized by the presence of a power-Maxwell field, surrounded by the quintessence fluid. The calculations are carried out by employing the WKB approximations up to the 13th-order, as well as the matrix method. The temporal evolution of the quasinormal modes is investigated by using the finite difference method. Through numerical simulations, the properties of the quasinormal frequencies are analyzed, including those for the extremal black holes. Among others, we explore the case of a second type of extremal black holes regarding the Nariai solution, where the cosmical and event horizon coincide. The results obtained by the WKB approaches are found to be mostly consistent with those by the matrix method. It is observed that the magnitudes of both real and imaginary parts of the quasinormal frequencies increase with increasing [Formula: see text], the spin–orbit quantum number. Also, the roles of the parameters [Formula: see text] and [Formula: see text], associated with the electric charge and the equation of state of the quintessence field, respectively, are investigated regarding their effects on the quasinormal frequencies. The magnitude of the electric charge is found to sensitively affect the time scale of the first stage of quasinormal oscillations, after which the temporal oscillations become stabilized. It is demonstrated that the black hole solutions for Rastall gravity in asymptotically flat spacetimes are equivalent to those in Einstein gravity, featured by different asymptotical spacetime properties. As one of its possible consequences, we also investigate the behavior of the late-time tails of quasinormal models in the present model. It is found that the asymptotical behavior of the late-time tails of quasinormal modes in Rastall theory is governed by the asymptotical properties of the spacetimes of their counterparts in Einstein gravity.

Shadow cast of noncommutative black holes in Rastall gravity

We study the shadow and energy emission rate of a spherically symmetric noncommutative black hole in Rastall gravity. Depending on the model parameters, the noncommutative black hole can reduce to the Schwarzschild black hole. Since the nonvanishing noncommutative parameter affects the formation of event horizon, the visibility of the resulting shadow depends on the noncommutative parameter in Rastall gravity. The obtained sectional shadows respect the unstable circular orbit condition, which is crucial for physical validity of the black hole image model.

Thermodynamic of the charged AdS black holes in Rastall gravity: P − V critical and Joule–Thomson expansion

In this paper, we study the thermodynamic of the charged AdS black holes in Rastall gravity. Firstly, the thermodynamic quantities of the charged AdS black holes in Rastall gravity are reviewed and the state equation of this black hole is obtained. Then, we investigate the [Formula: see text] critical and the Joule–Thomson expansion of the charged AdS black holes in Rastall gravity in which the critical temperature and the critical exponents are obtained. In addition, we get the inversion temperature and plot the isenthalpic and inversion curves in the [Formula: see text] plane, and also determine the cooling-heating regions of this black hole through the Joule–Thomson expansion. Finally, we investigate the ratio between the minimum inversion and critical temperatures, and find that the Rastall constant [Formula: see text] does not affect of this ratio.

Dynamics of charged and rotating NUT black holes in Rastall gravity

In this work, the Kerr–Newman-NUT black hole solution in Rastall gravity is proposed and it turns out that the horizon is [Formula: see text] dependence. Black hole dynamics such as the event horizons, ergosurface, zero angular momentum observer (ZAMO), thermodynamic properties, and the equatorial circular orbit around the black hole such as static radius limit, null equatorial circular orbit, and innermost stable circular orbit are investigated in this work. How the NUT and Rastall parameter affect the dynamic of the black hole is also shown.

Critical Phenomena of Charged AdS Black Holes in Rastall Gravity

We construct analytical charged anti-de Sitter (AdS) black holes surrounded by perfect fluids in four dimensional Rastall gravity. Then, we discuss the thermodynamics and phase transitions of charged AdS black holes immersed in regular matter like dust and radiation, or exotic matter like quintessence, ΛCDM type, and phantom fields. Surrounded by phantom field, the charged AdS black hole demonstrates a new phenomenon of reentrant phase transition (RPT) when the parameters Q, Np, and ψ satisfy some certain condition, along with the usual small/large black hole (SBH/LBH) phase transition for the surrounding dust, radiation, quintessence, and cosmological constant fields.

Scalar quasinormal modes of nonlinear charged black holes in Rastall gravity

In this paper, the scalar quasinormal modes of nonlinear charged black hole metrics in Rastall gravity is investigated. The electromagnetic tensor presented in the background spacetime possesses a power-law form, and the system is assumed to be surrounded by a quintessence field. By utilizing the recently obtained analytic form of the metric, the quasinormal frequencies are obtained via the matrix method. The numerical values have been further compared against those evaluated by using the WKB approximation up to thirteenth order. Also, the finite difference method is utilized to study the temporal evolution of the scalar perturbations. In terms of calculations carried out for both massless and massive scalar fields, we discuss the properties of the resultant quasinormal frequencies, as well as their dependences on the model parameters describing the background black hole. To be specific, the effect of the electric charge, mass of the scalar field, and equation of state of the quintessence are examined. Besides, the quasinormal frequencies associated with an extremal black hole regarding the Nariai limit is explored, where the obtained results are found to be consistent with theoretical arguments. The black hole metric is found to be stable against scalar perturbations, in the presence of both linear and nonlinear electromagnetic fields.

Solar system tests in Rastall gravity

In this paper, we have investigated the classical tests of General Relativity like precession of perihelion, deflection of light and time delay by considering a phenomenological astrophysical object like Sun, as a neutral regular Hayward black hole in Rastall gravity. We have tabulated all our results for some appropriate values of the parameter [Formula: see text]. We have compared our values with [Formula: see text], which corresponds to the Schwarzschild case. Also the value of [Formula: see text] is of particular interest as it gives some promising results.