AdS Black Holes Research Articles

Stability and Hawking-Page-like phase transition of phantom AdS black holes

In this work, we investigate the thermodynamic stability and phase structure of AdS black holes with either a Maxwell field (where we revisit past studies) or a phantom field. We conduct a comprehensive analysis of the free energy and temperature of these systems in both the canonical and grand canonical ensembles. Our findings reveal the occurrence of a phase transition in the grand canonical ensemble, resembling the Hawking-Page-like phase transition observed between the thermal radiation of AdS spacetime and thermodynamically stable large black holes. We present graphical representations of these phase transitions on free energy-temperature diagrams for the black holes. Completing our study, we obtain the transition temperature, minimum temperature and their dual relations.

Holographic thermal correlators: a tale of Fuchsian ODEs and integration contours

We analyze real-time thermal correlation functions of conserved currents in holographic field theories using the grSK geometry, which provides a contour prescription for their evaluation. We demonstrate its efficacy, arguing that there are situations involving components of conserved currents, or derivative interactions, where such a prescription is, in fact, essential. To this end, we first undertake a careful analysis of the linearized wave equations in AdS black hole backgrounds and identify the branch points of the solutions as a function of (complexified) frequency and momentum. All the equations we study are Fuchsian with only regular singular points that for the most part are associated with the geometric features of the background. Special features, e.g., the appearance of apparent singular points at the horizon, whence outgoing solutions end up being analytic, arise at higher codimension loci in parameter space. Using the grSK geometry, we demonstrate that these apparent singularities do not correspond to any interesting physical features in higher-point functions. We also argue that the Schwinger-Keldysh collapse and KMS conditions, implemented by the grSK geometry, continue to hold even in the presence of such singularities. For charged black holes above a critical charge, we furthermore demonstrate that the energy density operator does not possess an exponentially growing mode, associated with ‘pole-skipping’, from one such apparent singularity. Our analysis suggests that the connection between the scrambling physics of black holes and energy transport has, at best, a limited domain of validity.

Lyapunov exponents and phase transitions of Born-Infeld AdS black holes

In this paper, we characterize the phase transitons of Born-Infeld AdS black holes in terms of Lyapunov exponents. We calculate the Lyapunov exponents for timelike geodesics in background metric and photon geodesics in effective metric. It is found that black hole phase transitions can be described by multiple-valued Lyapunov exponents. And its phase diagram can be characterized by Lyapunov exponents and Hawking temperature. Besides, the change of Lyapunov exponents can be considered as order parameter, and exists a critical exponent 1/2 near critical point.

Correlated stability conjecture for AdS black holes in higher dimensional Ricci cubic gravity

Correlated stability conjecture for AdS black holes in higher dimensional Ricci cubic gravity

Boundary terms and conserved charges in higher-derivative gauged supergravity

We address some issues in higher-derivative gauged supergravity with Chern-Simons terms, focusing on the five-dimensional case. We discuss the variational problem with Dirichlet boundary conditions as well as holographic renormalization in asymptotically locally AdS spacetimes, and derive the corresponding boundary terms. We then employ Wald’s formalism in order to define conserved charges associated to local symmetries (diffeomorphisms and U(1) gauge transformations), taking into account the effect of generic gauge Chern-Simons terms. We prove that the first law of black hole mechanics and the quantum statistical relation hold in this setup. Chern-Simons terms also lead us to distinguish between Noether charges and Page (or Komar) charges which satisfy the Gauss law. We make use of the latter to compute corrections to the angular momentum and electric charge of the supersymmetric black hole in AdS5 from its corrected near-horizon geometry. This also allows us to derive the microcanonical form of the entropy as a function of the conserved charges relying entirely on the near-horizon geometry. Finally, we comment on four-derivative gauged supergravity in four dimensions, showing that field redefinitions permit to simplify the action at linear order in the corrections, so that the equations of motion are those of the two-derivative theory.

Charged AdS black holes in 4D Einstein–Gauss–Bonnet massive gravity

Charged AdS black holes in 4D Einstein–Gauss–Bonnet massive gravity

Joule-Thomson effect of AdS black holes in conformal gravity

We investigate the Joule-Thomson effect of AdS black holes in conformal gravity. We derive the Joule-Thomson coefficient in terms of thermodynamic relations and then make an alternative derivation via a direct way. We analyze the Joule-Thomson coefficient and find that the Joule-Thomson coefficients obtained from two different approaches are equal. Moreover, we present a novel isenthalpic process in which the inversion temperature is minimal and it separates the corresponding heating-cooling phase. We analyze the inversion temperature and its corresponding inversion curve that separates the regions for the JT effect to be allowable and forbidden, where such an effect can only be observed in the allowable region. We also discuss the effects of two important parameters on the inversion curves.

Comments on Sen's classical entropy function for static and rotating AdS4 black holes

We consider various aspects of Sen's classical entropy function formalism for asymptotically AdS4 black holes with emphasis on its efficacy to capture higher derivative corrections to the Bekenstein-Hawking entropy. The formalism has the important advantage of being based on near-horizon symmetries and does not require knowledge of the full interpolating supergravity solution, nor of its AdS4 asymptotics. For the static case, we focus on applying the entropy function formalism in the presence of various higher derivative terms motivated in conformal supergravities; we find agreement with recently reported results utilizing the full black hole solutions and Wald's entropy formula. For the rotating case, we demonstrate that a modified version of the formalism generates a background that coincides precisely with the Bardeen-Horowitz limit of known rotating, electrically charged AdS4 black holes and provides a swift approach to the black hole entropy, including higher derivatives corrections. We conclude that Sen's classical entropy function formalism is a viable and highly efficient approach to capturing higher-derivative corrections to the entropy of asymptotically AdS4 black holes albeit naturally missing certain relations arising from global aspects of the full black hole solution.

Nonlinear Yang-Mills black holes

This paper is devoted to investigating the nonlinear non-abelian Yang-Mills black holes. We consider three Born-Infeld, exponential, and logarithmic nonlinear Yang-Mills theories with SO(n−1) and SO(n−2,1) semi-simple groups, which n is the dimension of spacetime, and obtain a new class of nonlinear Yang-Mills (NYM) black hole solutions. Depending on the values of dimension n, Yang-Mills charge e and the mass m and nonlinear parameters β, our solutions can lead to a naked singularity, a black hole with two horizons, an extreme or a Schwarzschild-type black hole. We also investigate the thermodynamic behaviors of the NYM black holes. For small charge values, the NYM solutions may be thermally stable in the canonical ensemble, if we consider an AdS spacetime with spherical k=+1 and hyperbolic k=−1 coordinates or a flat one with k=+1. However, there are no stable regions in the grand canonical ensemble in higher dimensions. For the NYM black hole, we observe a reentrant phase transition between large and small black holes in the BI-branch with small β, which cannot be visible for the nonlinear Reissner-Nordstrom AdS black hole in the higher dimension. For the limit β→∞, the critical ratio PcvcTc tends to the constant value 3/8 for each dimension n, while it depends on the dimension for the case of nonlinear electrodynamics black holes.

Circular motion and chaos bound of a charged particle near charged 4D Einstein–Gauss–Bonnet-AdS black holes

The circular motion and chaos bound of one charged particle near 4D charged AdS black holes in the Einstein–Gauss–Bonnet gravity theory are analytically investigated. With the help of the Jacobian matrix, we construct the actual formula of the Lyapunov exponent for the charged particle, which satisfies the upper bound when it is localized at the event horizon. Further considering the Lyapunov exponent in the vicinity of the horizon and studying the 4D charged Einstein–Gauss–Bonnet-AdS black hole with different Gauss–Bonnet coupling coefficients, it is found that it has some specific values to determine whether a violation of chaos bound. The Lyapunov exponent for the circular motion of charged test particle is larger than the static equilibrium because of the appearance of angular momentum. We find that, with the increase of the Gauss–Bonnet coupling coefficient, the black hole gets closer to the extremal state and the bound is more easily violated. For various Gauss–Bonnet coupling coefficients, we obtain a corresponding range of the particle charge, in which the chaos bound is violated. Our results indicate that, as the Gauss–Bonnet coupling coefficient increases, the value of the particle charge violating the chaos bound is even smaller.

More exact thermodynamics of nonlinear charged AdS black holes in 4D critical gravity

In this paper, we investigate nonlinearly charged AdS black holes in four-dimensional critical gravity and study more exact black hole thermodynamics under the effect of small statistical fluctuations. We compute the correction to the thermodynamics of nonlinearly charged AdS black hole up to the leading order. We discuss the stability of black holes under the circumstances of fluctuation and find that fluctuation causes instability in the black holes. Moreover, both the isothermal and adiabatic compressibilities are also derived. Finally, we estimate the role of small fluctuations on the equation of states and study the P−v diagram of nonlinearly charged AdS black hole.

Entropy inside the Kerr–Sen black holes

In this paper, we consider the Kerr–Sen black hole. Unlike the AdS black hole, it is actually an exact solution for the heterotic string theory in the low energy effective field theory in four dimensions. Starting from the black hole metric in the Boyer–Lindquist coordinates, we calculate the maximal interior volume by introducing the advanced time. Further, we present the rate of change of the interior volume with the advanced time on the radius of the black hole and observe that it has a maximal value for a specific value of the radius of the black hole. It is also shown from the graph that the maximal value increases with the increase of mass, and the position of the maxima shifts towards the large radius. Moreover, we calculate the rate of loss of mass due to Hawking radiation and interpret it graphically. Finally, we compute the interior entropy and show from its variations with mass and outer horizon radius of the black hole that in the interior, the entropy decreases with mass and becomes negative, whereas, in the exterior, the entropy increases with mass and remains positive. This is further proof of the argument that was proposed in Azuma and Subramanian (2020). In this investigation, an interesting feature is that the low-mass Kerr–Sen black hole behaves like a reversible process, whatever its outer horizon also reveals.

Aspects of thermal one-point functions and response functions in AdS black holes

We revisit the problem of analytically computing the one-point functions for scalar fields in planar AdS black holes of arbitrary dimension, which are sourced by the Weyl squared tensor. We analyze the problem in terms of power series expansions around the boundary using the method of Frobenius. We clarify the pole structure of the final answer in terms of operator mixing, as argued previously by Grinberg and Maldacena. We generalize the techniques to also obtain analytic results for slowly modulated spatially varying sources to first nontrivial order in the wave vector for arbitrary dimension. We also study the first-order corrections to the one-point function of the global AdS black hole at large mass, where we perturb in terms that correspond to the curvature of the horizon.

SL(2, R) × U(1) symmetry and quasinormal modes in the self-dual warped AdS black hole

The algebraic approach to the spectrum of quasinormal modes has been made as simple as possible for the BTZ black hole by the strategy developed in [16]. By working with the self-dual warped AdS black hole, we demonstrate in an explicit way that such a strategy can be well adapted to those warped AdS balck holes with the SL(2, R) × U(1) isometry. To this end, we first introduce two associated tensor fields with the quadratic Casimir of SL(2, R) × U(1) Lie algebra in the self-dual warped AdS black hole and show that they correspond essentially to the metric and volume element up to a constant prefactor, respectively. Then without appealing to any concrete coordinate system, we can further show that the solutions to the equations of motion for the scalar, vector, spinor fields all fall into the representations of the SL(2, R) × U(1) Lie algebra by a purely abstract tensor and spinor analysis. Accordingly, the corresponding spectrum of quasinormal modes for each fixed azimuthal quantum number can be derived algebraically as the infinite tower of descendants of the highest weight mode of the SL(2, R) Lie subalgebra.

Solutions and basic properties of regularized Maxwell theory

The regularized Maxwell theory is a recently discovered theory of nonlinear electrodynamics that admits many important gravitating solutions within the Einstein theory. Namely, it was originally derived as the unique nonlinear electrodynamics (that depends only on the field invariant ${F}_{\ensuremath{\mu}\ensuremath{\nu}}{F}^{\ensuremath{\mu}\ensuremath{\nu}}$) whose radiative solutions can be found in the Robinson-Trautman class. At the same time, it is the only electrodynamics of this type (apart from Maxwell) whose slowly rotating solutions are fully characterized by the electrostatic potential. In this paper, after discussing the basic properties of the regularized Maxwell theory, we concentrate on its spherical electric solutions. These not only provide ``the simplest'' regularization of point electric field and its self-energy, but also feature complex thermodynamic behavior (in both canonical and grand canonical ensembles) and admit an unprecedented phase diagram with multiple first-order, second-order, and zeroth-order phase transitions. Among other notable solutions, we construct a novel C-metric describing accelerated AdS black holes in the regularized Maxwell theory. We also present a generalization of the regularized Maxwell Lagrangian applicable to magnetic solutions, and find the corresponding spherical, slowly rotating, and weakly Newman-Unti-Tamburino charged solutions.

Charged Accelerating BTZ Black Holes

AbstractIn this paper, general uncharged accelerating BTZ black hole solutions are extracted and studied some of their properties. The analysis shows that spacetime's asymptotic behavior depends on four parameters: the cosmological constant, mass, acceleration, and topological constant. Then, the temperature of these black holes are studied and it is found that the temperature is always positive for AdS spacetime. Next, the study is extended for extracting charged accelerating BTZ black hole solutions in the presence of a nonlinear electrodynamics field known as conformally invariant Maxwell. The findings indicate a coupling between the electrical charge and other quantities of the accelerating BTZ black holes. The asymptotic behavior of charged accelerating BTZ black holes depends on five parameters: the cosmological constant, the electrical charge, mass, the acceleration parameter, and the topological constant. Then, the effects of charge, acceleration parameters, and the topological constant on the root of these black holes are studied. Finally, the temperature of these black holes in AdS spacetime is investigated. For these black holes, the temperature depends on the electrical charge, accelerating parameter, and the cosmological constant. The analysis indicates that the temperature of charged accelerating BTZ AdS black holes is always positive.

Effect of a cloud of strings and quintessence on a phase transition of charged rotating AdS black holes

Effect of a cloud of strings and quintessence on a phase transition of charged rotating AdS black holes

Thermodynamics of phase transition in Reissner–Nordström–de Sitter spacetime

The Reissner-Nordstrm̈-de Sitter (RN-dS) spacetime can be considered as a thermodynamic system. Its thermodynamic properties are discussed that the RN-dS spacetime has phase transitions and critical phenomena similar to that of the Van de Waals system or the charged AdS black hole. The continuous phase transition point of RN-dS spacetime depends on the position ratio of the black hole horizon and the cosmological horizon. We discuss the critical phenomenon of the continuous phase transition of RN-dS spacetime according to Landau theory of continuous phase transition, that the critical exponent of spacetime is same as that of the Van de Waals system or the charged AdS black hole, which have universal physical meaning. We find that the order parameters are similar to those introduced in ferromagnetic systems. Our universe is an asymptotically dS spacetime, thermodynamic characteristics of RN-dS spacetime can help us understand the evolution of spacetime and provide a theoretical basis to explore the physical mechanism of accelerated expansion of the universe.

Critical behavior of AdS black holes surrounded by dark fluid with Chaplygin-like equation of state

Supposing the existence of Dark Fluid with a Chaplygin-like equation of state $p=-B/\rho$ (CDF) as a cosmic background, we obtain a static spherically-symmetric black hole (BH) solution to the Einstein gravitational equations. We study the $P-V$ critical behavior of AdS BH surrounded by the CDF in the extended phase space where the cosmological constant appears as pressure, and our results show the existence of the Van der Waals like small/large BH phase transition. Also, it is found that such a BH displays a first-order low/high-$\Phi$ BH phase transition and admits the same criticality with van der Waals liquid/gas system in the non-extended phase space, where the normalization factor $q$ is considered as a thermodynamic variable, while the cosmological constant being fixed. In both $P-V$ and the newly proposed $q-\Phi$ phase spaces, we calculate the BH equations of state and then numerically study the corresponding critical quantities. Moreover, the critical exponents are derived and the results show the universal class of the scaling behavior of thermodynamic quantities near criticality. Finally, we study the shadow thermodynamics of AdS BHs surrounded by the CDF. We find that, there exists a positive correlation between the shadow radius and the event horizon radius in our case. By analyzing the temperature and heat capacity curves under the shadow context, we discover that the shadow radius can replace the event horizon radius to demonstrate the BH phase transition process, and the changes of the shadow radius can serve as order parameters for the small/large BH phase transition, indicating that the shadow radius could give us a glimpse into the BH phase structure from the observational point of view.

Subregion entropy for the doubly-holographic global black string

We study the growth of entanglement entropy in a doubly holographic model of gravity for a spherical AdS black hole. Compared to previous work, which was limited to the case of planar black holes, this introduces an extra scale to the problem. This allows us to analyze the interplay between the reorganization of entanglement entropy due to island formation and the onset of the Hawking-Page phase transition and to find the appearance of a new critical black hole radius unrelated to the thermodynamics. We also find that the geometry of the Ryu-Takayanagi surface capturing the physics of islands exhibits drastically different behavior than in the planar case.