arXiv subjects

Supakchai Ponglertsakul

Publications and source records attributed to Supakchai Ponglertsakul.

At least 19 recordsLinked to original sources

arXiv2026

Generalized Polytropic Regular Black Holes in Arbitrary Dimensions

We investigate static, spherically symmetric regular black holes with anti-de Sitter (AdS) asymptotics in arbitrary spacetime dimensions. They are solutions of Einstein gravity, sourced by an anisotropic fluid whose radial pressure corresponds to vacuum energy, while the tangential pressure satisfies a generalized polytropic equation of state. By solving the Einstein field equations, we derive a generic class of asymptotically AdS black hole solutions and determine the conditions required for spacetime regularity. We then investigate the dynamical formation of these regular black holes within the thin-shell formalism, assuming a linear barotropic equation of state for the shell matter. Next, we study the thermodynamics of the regular AdS black holes in arbitrary dimensions by verifying the first law of black hole thermodynamics and the corresponding Smarr relation. We analyze the thermodynamic stability and phase structure of solutions in four, five, and six spacetime dimensions, demonstrating the existence of dimension-dependent phase transitions.

gr-qc↗

arXiv2026

A Novel Kerr-like Black Hole in a General Double Power Law Dark Matter Environment: Geometry, Spectroscopy, and Energy Extraction

We construct a novel Kerr-like black hole solution embedded in a general double power law dark matter environment by applying the Newman--Janis algorithm to a Schwarzschild-like seed geometry. This framework provides a unified rotating spacetime for arbitrary double power law density profiles and reveals how dark matter modifies the horizon structure, extremal spin, and curvature properties of rotating black holes. Remarkably, we find that the rotation--halo interplay can eliminate essential curvature singularities for Dehnen-type profiles with $γ\leq2$, despite the singular nature of the corresponding static configurations. We then investigate the spectroscopic signatures of the dark matter environment through massive scalar perturbations in the Dehnen $(1,4,γ)$ halo. Using an analytical low-frequency matching method, we derive the quasibound state spectrum, the onset condition for scalar cloud formation, and superradiant amplification factor, showing that the halo parameters $ρ_0 r_0^3$ and $γ$ leave characteristic imprints on the scalar spectrum. Increasing the halo density or the cusp strengthens the binding of quasibound states and enhances their decay, shifts the scalar cloud threshold, and suppresses superradiant amplification effectivity by narrowing the allowed frequency window and lowering the amplification factor peak. Finally, we analyze rotational energy extraction from thermal scalar fields and demonstrate that the efficiency is controlled by the interplay between the thermal spectrum and the superradiant instability, with lower temperatures and less cuspy density profiles yielding more efficient energy extraction.

gr-qc↗

arXiv2026

Chiral Quartic Massive Gravity in Three Dimensions

We study New Massive Gravity (NMG) with Chern-Simons (CS), cubic, and quartic terms under the Compère-Song-Strominger (CSS) boundary conditions. By employing a semi-product of a Virasoro and a $U(1)$ Kac-Moody current algebra as the asymptotic symmetry algebra, we calculate the entropy of BTZ black holes via the degeneracy of states belonging to a Warped-CFT. Then, we compute the linearized energy excitations using the representations of the algebra $U(1)\times SL(2, R)_{R}$ and demonstrate that the energies of excitations are non-negative at two chiral points in the parameter space.

hep-th↗

arXiv2026

More on near-horizon charges black holes with gravitational hair in three dimensions

With the aim of continuing the exploration of near-horizon charges in higher-curvature gravity, searching for sectors leading to universal behaviors, we first provide a thorough revision and formulae of the covariant phase-space method applied to arbitrary gravitational theories containing up to quartic terms in the Riemann tensor in arbitrary dimension. These results can be applied in diverse setups, in particular in the context of $α'$ corrections to String Theory, where it is known that in Type II theories, the first correction to the Einstein-Hilbert Lagrangian goes as $α'^3 \mathcal{R}^4$. Then, we test these formulae for near horizon asymptotic symmetries of the rotating BTZ spacetime where the first law of black hole thermodynamics is consistently recovered. It was recently realized that a subset of these higher curvature gravities do admit black holes with gravitational hair, whose entropy can be microscopically accounted for, as is the case of New Massive Gravity. In this case, the four maximally symmetric vacua of the theory coincide, and the theory acquires an extra gauge symmetry when linearized around such a vacuum. We study the near-horizon asymptotic symmetries and compute the associated charges, both in the static and rotating hairy black holes, extending up to $\mathcal{R}^4$, a work that was previously done only up to a quadratic term. In order to allow for a continuous lecture on the work, we report the explicit expressions of the general Lagrangians in the appendices.

gr-qc↗

arXiv2026

Novel exact black hole solution in Dehnen $\left(1,4,\frac32\right)$ halo thermodynamics, photon circular motion and eikonal quasinormal modes

Dehnen $(1,4,\frac32)$ dark matter halo has been proven to be a valuable model for describing the surface brightness distributions of elliptical galaxies, yet its implications for black hole spacetimes remain largely unexplored. In this work, we construct a novel exact black hole solution embedded in this Dehnen halo and investigate its physical consequences. The influence of the halo on black hole thermodynamics is analyzed through the mass function, entropy, Hawking temperature, heat capacity, and Gibbs free energy, allowing us to assess both local and global thermodynamic stability of the black hole-dark matter system. Our results show that the presence of a Dehnen-type halo not only stabilizes the otherwise thermodynamically unstable Schwarzschild black hole but also induces phase transitions. In addition, we study null geodesics to examine photon motion, the shadow radius and the optical appearance of the system. The dark matter halo modifies the effective potential, leading to observable changes in the photon sphere and the apparent size of the shadow. We also explore the instability of circular null geodesics and its relation to quasinormal modes in an eikonal limit. These findings highlight the significant role of realistic dark matter distributions in shaping both the thermodynamic behavior and the observable signatures of black holes, providing further insight into the interplay between dark matter halos and central black holes in galaxies.

gr-qc↗

arXiv2025

Optical Signatures of q-deformed solution in Einstein-Maxwell-dilaton Gravity

We consider null geodesics in the background of spherically symmetric object in Einstein-Maxwell-Dilaton (EMD) theory with coupling function $f(Φ)=e^{-2λΦ}$. The spherical solution is characteristically described by dilaton coupling $λ$, integrated dilaton flux $D$ and magnetic charge $P$. Then, we derive geodesic equations by using the Hamilton-Jacobi approach. The radial photon orbital equation on equatorial plane and effective potential are analyzed. The total deflection angle and trajectories of photon as a function of impact parameter $b$ are plotted with the variation of $λ,D$ and $P$. Furthermore, the relation between photon ring's width and the Lyapunov exponent is also explored. In addition, we use the Gralla-Lupsasca-Marrone (GLM) model to model intensity profile of optically thin accretion disk around the object. Hence, we construct optical images of the object surrounded by three distinct emission profiles. Lastly, we investigate the radius of innermost stable circular orbit (ISCO) for timelike geodesics.

gr-qc↗

arXiv2025

Boundary Conditions of Warped AdS$_3$ in New Massive Gravity

To satisfy the Cardy formula for Warped AdS$_3$ (WAdS$_{3}$) solutions in a quadratic ensemble, a specific set of boundary conditions has been proposed in \cite{Aggarwal:2020igb}. In this paper, these boundary conditions have been investigated in the three-dimensional new massive gravity (NMG) framework. The associated solution space, asymptotic symmetries, and charge algebra have been extracted. It has been shown that the surface charges are finite, but not integrable, and the integrability of the charges is obtained after restricting to a sub-sector of the original solution space. Finally, we have proved that the Cardy formula reproduces the thermodynamic entropy of a warped BTZ black hole.

hep-th↗

arXiv2025

The Spectroscopy of the 2+1 Dimensional Analog Black Hole in Photon-Fluid Model

In this paper, we explore quasibound states (QBS), scalar cloud, Hawking radiation, superradiance, and greybody factor of relativistic massive phonon modes in a photon-fluid rotation black hole. We investigate quasibound states and scalar clouds using exact eigensolutions to the analog Klein-Gordon equation in the analog black hole background and revisit the Wentzel-Kramers-Brillouin (WKB) upper bound on the scalar clouds' energy ratio. Using the obtained exact radial solution, we use the Damour-Ruffini method to calculate the power spectrum of the analog black hole's Hawking radiation. We then use the analytical asymptotic matching technique (AAM) to investigate the analog black hole's superradiance for low energy massive photon scattering, resulting in the analytical amplification factor and the greybody factor formulas of the analog black hole. We discover that the analog black hole in the photon-fluid model is superradiant with an energy range of $\varpi < ω<m_\ellΩ_H$. As a result, the greybody factors are negative for co-rotating modes in the superradiant regime.

gr-qc↗

arXiv2025

The gravitational wave echoes from the black hole with three-form fields

In this work, we study of massless three-form black hole, where the three-form fields are higher $p$-form gauge fields with $p=3$. These give rise to the Schwarzschild-de Sitter (Sch-dS)-like solution through an effective cosmological constant represented by $a_1$. We analyze this solution under gravitational perturbations and find that it exhibits a single-peak potential. For this case, no echoes are produced. Furthermore, we consider the massive case of the three-form fields by introducing a Stueckelberg field to restore gauge invariance and to investigate its effect on GWs at late times. In this case, the potential exhibits a double-peak structure, with the modified potential appearing beside the gravitational perturbation potential. We also examine the impact of the relevant parameters as well as the influence of the parameter $c_0$, which arises from the equation of motion of the Stueckelberg field. For a large value of $a_1$, the two peaks of the potentials are close together, while $c_0$ affects the amplitude and decay rate of the time-domain waveform, resulting in no echoes. For small values of $a_1$, the peaks of the potentials are widely separated and $c_0$ influences both the phase and the amplitude of the echoes. In addition, the quasinormal frequencies of the black hole are also calculated using both the WKB and Prony methods. As results, these provide a potential avenue for testing deviations from GR and probing possible signatures of quantum gravity through future GWs observations.

gr-qc↗

arXiv2025

Superradiance of Charged Static Black Hole in Cubic Gravity

Higher curvature gravity usually has complicated field equations, and solving them analytically is strenuous. In this work, we obtain an analytical charged black hole (BH) solution in higher curvature gravity using the thermodynamics of black holes and employing the continued fraction expansion. We investigate the thermodynamics of static black holes using the first law of thermodynamics and the Smarr formula in their proper form for Einstein-cubic gravity (ECG). Next, we obtain the thermodynamic quantities and show that our results are similar to those from solving the field equations. Then, we study the superradiance of the black hole using massless charged-scalar perturbations. We derive the superradiant conditions and compute the amplification factor through direct integration. We demonstrate how the amplification factor will change as a function of the black hole charge and frequency of the incident wave. We also show that a black hole mass and charge are decreasing in the superradiance region. Finally, we discuss superradiance as a consequence of black hole thermodynamics in ECG.

gr-qc↗

arXiv2025

Slowly rotating black hole solution to Einstein-Bel-Robinson gravity

We study slowly rotating black hole solutions in the Einstein-Bel-Robinson gravity (EBR) in four dimensions. At the leading order in the rotation parameter, the only modification with respect to the static case is the appearance of a non-vanishing $g_{tϕ}$ component. We construct approximate solutions to these equations and study how physical properties of the solutions, such as the angular velocity, photon sphere, black hole shadow, and innermost stable circular orbit, are modified, working to leading order in the coupling constant and the rotation parameter. Finally, we study the superradiance of a massive scalar wave scattering off slowly rotating black holes. Using direct integration, we derive the superradiant conditions and compute the energy flux through the event horizon and amplification factor. We demonstrate how the flux and amplification factor will change as a function of the black hole rotation and frequency of the incident wave.

gr-qc↗

arXiv2025

Physical Properties of Black Hole Solution in Einstein-Bel-Robinson Gravity

In this paper, we study the different properties of static spherically symmetric black hole solutions of Einstein-Bel-Robinson gravity (EBR), a modified four-dimensional theory of gravity quartic in curvature. We look at the orbit of massless and massive test bodies near a black hole, specifically computing the innermost stable circular orbit and photon sphere and finding them smaller than their Einstein counterparts in general relativity. Next, we obtain the deflection angle and shadow by an EBR black hole and find that both decreased compared to a non-rotating black hole in general relativity. We obtain a bound value for the coupling constant using the Shapiro time delay. Then, we explore the EBR black hole's lifetime and find that it decreases to Einstein's gravity. Quasinormal modes (QNMs) are computed using Padé averaged 6th order WKB method showing that increasing the coupling constant lowers the damping rate of ring-down gravitational waves (GWs). The oscillation frequency of scalar QNMs decreases with the coupling constant, whereas it increases for electromagnetic QNMs. We also provide analytical rigorous bound of greybody factor. We show that the coupling constant has a small effect on the greybody factor. Finally, correspondence between greybody factor and quasinormal modes is also considered.

gr-qc↗

arXiv2025

Constructing regular black holes from multi-polytropic equations of state

Regular black holes are imagined as solutions to Einstein's field equations, with no singularities, albeit characterized by the presence of an internal structure. With the intention not to use non-linear electrodynamics, we here propose to obtain new classes of solutions that can also satisfy the Tolman-Oppenheimer-Volkoff (TOV) equations, plus adding a non-zero core. Thus, we present regular black holes as solutions to the TOV equations using multipolytropic equations of state and investigate whether these solutions behave, tuning the underlying free parameters. Our analysis demonstrates that, within specific parameter ranges, repulsive gravity effects may occur in precise regions. Accordingly, black hole remnants are also investigated, showing that, under certain circumstances, they may turn into dark energy sources in view of the corresponding repulsive gravity effects, located outside the horizons. Moreover, quite remarkably, critical sets of parameters imply that solutions may exhibit transitions to regular repulsive relativistic compact objects from black hole behaviors. Finally, we explore the interpretation of these regular black hole solutions in terms of topological thermodynamic defects.

gr-qc↗

arXiv2025

The Spectroscopy of Kerr-Einstein-Maxwell-Dilaton-Axion: Exact Quasibound States, Scalar Cloud, Horizon's Boson Statistics and Superradiance

In the present study, we investigate the quasibound states, scalar cloud and superradiance of relativistic scalar fields bound to a rotating black hole in Einstein-Maxwell-Dilaton-Axion theory (Kerr-EMDA). We present the exact eigensolutions of the governing Klein-Gordon equation in the black hole background. By imposing boundary conditions on the quasibound states, we are able to find the exact complex quasibound state frequencies of the corresponding radial wave functions in terms of the confluent Heun polynomial. Considering light scalar field limit of the obtained solution, we investigate the scalar-black hole resonance configuration known as the scalar cloud. In addition, we obtain analytic relation between light scalar mass and black hole spin for scalar cloud. We explore a boson distribution function by linearly expanding the radial wave function near the black hole's event horizon. Moreover, by applying the Damour-Ruffini method, this allows us to calculate the Hawking radiation flux. In the final section, we consider propagating wave in a slowly rotating Kerr-EMDA black hole for bosons having much larger Compton wavelength comparing to the size of rotating black hole. This condition allows us to use the asymptotic matching technique to calculate the amplification factor for scalar fields in the Kerr-EMDA black hole. We present the dependence of amplification factor on black hole parameters by graphical analysis.

gr-qc↗

arXiv2025

The extremal Reissner-Nordström black holes: an exact charged scalar quasiresonance

In this letter, we present a novel exact scalar quasibound states solutions in the extremal Reissner-Norström black hole background. We start with the construction of the governing covariant relativistic scalar field equation, the Klein-Gordon equation in the extremal Reissner-Norström black hole background and applying the separation of variables anzat. The exact relativistic scalar wave's angular solution is found in terms of the spherical harmonics while the two independent radial wave solutions are, for the first time, exactly found and presented in terms of the double confluent Heun functions. The solutions are settled in the gravitational potential well and behave like an ingoing waves approaching black hole's horizon, vanishing when approaching infinity. The gravitationally bounded charged massive scalar fields are found to have quantized complex valued energy levels while imaginary energy levels are obtained for the charged massless scalar field, of both cases, indicating decaying states. Further investigation shows that the extreme Reissner-Nordstöm black hole does not support scalar cloud. And with the help of the obtained exact radial solutions, the Hawking radiation of the extremal Reissner-Nordstöm black hole is investigated and we find the zero temperature of the black hole's horizon.

gr-qc↗

arXiv2024

Noncommutative black hole in de Rham-Gabadadze-Tolley like massive gravity

We examine the behavior of non-commutative Schwarzschild black holes in the context of massive gravity. According to the investigation, corresponding to a minimal mass, the black hole can have two horizons, one horizon, or no horizon at all. Our results imply the existence of a stable black hole remnant, whose mass can be uniquely calculated in terms of the non-commutative parameter $θ$ and gravity mass $m$. Thermodynamic features such as heat capacity and Hawking temperature are studied. We also examine a scalar linear perturbation on the black hole. Quasinormal frequencies are computed via Wentzel-Kramers-Brillouin(WKB) method with Pade improvement. All quasinormal frequencies considered in this work have a negative imaginary part. In the eikonal limit, we investigate the angular velocity and the Lyapunov exponent as a function of $M/\sqrtθ$. Additionally, we explore the black hole's shadow across various model parameters. Our findings indicate that non-commutativity leads to a reduction in the black hole's shadow, with this effect exhibiting a nonlinear relationship. Furthermore, we observe that the inclusion of a massive graviton in the theory results in an increase in the black hole's shadow radius, particularly at greater observer distances.

gr-qc↗

arXiv2024

Constraints on Quasinormal modes from Black Hole Shadows in regular non-minimal Einstein Yang-Mills Gravity

This work deals with the scalar quasinormal modes using higher order WKB method and black hole shadow in non-minimal Einstein Yang-Mills theory. To validate the results of quasinormal modes, time domain profiles are also investigated. We found that with an increase in the magnetic charge of the black hole, the ring-down gravitational wave increases non-linearly and damping rate decreases non-linearly. The presence of magnetic charge also results in a decrease in the black hole shadow non-linearly. It is found that for large values of the coupling parameter, the black hole changes to a solitonic solution and the corresponding ring-down gravitational wave frequency increases slowly with a decrease in the damping rate. For the solitonic solutions, the shadow is also smaller. The constraints on the model parameters calculated using shadow observations of M87* and Sgr A* and an approximate analytic relation between quasinormal modes and shadow at the eikonal limit is discussed.

gr-qc↗