Dilaton Black Holes Research Articles

Dynamics of domain wall in charged AdS dilaton black hole space–time

For the [Formula: see text]-dimensional FRW domain wall universe induced by [Formula: see text]-dimensional charged dilaton black hole, observers on the domain wall interpret its movement in the bulk as the expansion or collapsing of universe. By analyzing, we found that in this static AdS space, the cosmologic behavior of domain wall is particularly single. Even more surprising, there is an anomaly that the domain wall has a motion area outside the horizon, which cannot be explained by our classical theory.

Inevitable degradation and inconsistency of quantum coherence in a curved space-time

Based on dynamic analyses on bipartition system, the frozen conditions and the inconsistency of quantum coherence are investigated when one qubit of initial state located in Garfinkle–Horowitz–Strominger (GHS) dilaton black hole. These conditions are derived that either the initial state is prepared in an incoherent state or only the antiparticles escape from the event horizon. In this sense, the degradation of coherence is unavoidable as the expansion of black hole. Moreover, the evolution trajectories of two coherence measures are explored, which are significantly affected by the initial state structure and the approximation quantization of black hole. We then conclude that this inconsistency is an intrinsic trait of coherence in the curved space-time. Additionally, we observe some relations among the norm coherences between different bipartition systems and, at the same time, obtain the entropy coherences with same expressions.

Dilaton black holes with power law electrodynamics

In this article, the new black hole solutions to the Einstein-power-Maxwell-dilaton gravity theory have been investigated in a four-dimensional space-time. The coupled scalar, electromagnetic and gravitational field equations have been solved in a static and spherically symmetric geometry. It has been shown that dilatonic potential, as the solution to the scalar field equation, can be written in the form of a generalized Liouville potential. Also, three classes of novel charged dilaton black hole solutions, in the presence of power law nonlinear electrodynamics, have been constructed out which are asymptotically non-flat and non-AdS. The conserved and thermodynamic quantities have been calculated from geometrical and thermodynamical approaches, separately. Since the results of these two alternative approaches are identical one can argue that the first law of black hole thermodynamics is valid for all of the new black hole solutions. The thermodynamic stability or phase transition of the black holes have been studied, making use of the canonical ensemble method. The points of type-1 and type-2 phase transitions as well as the ranges at which the black holes are stable have been indicated by considering the heat capacity of the new black hole solutions. The global stability of the black holes have been studied through the grand canonical ensemble method. Regarding the Gibbs free energy of the black holes, the points of Hawking-Page phase transition and ranges of the horizon radii at which the black holes are globally stable have been determined.

Charged dilaton solutions and black hole formation in three dimensions

In this paper, we present the charged dilaton solutions and black hole formation in three dimensions. Firstly we revisit the famous Chan–Mann charged dilaton black hole, describing one parameter family of static charged black hole solution in three dimensional Einstein–Maxwell–Dilaton gravity. This solution with a special parameter choice b=4a can lead to the three dimensional string solution. Then we give another class of charged dilaton black hole solution with bne 4a. We discuss their geometrical properties, the horizon structure and the causal structure. The time-dependent solution is also presented, which can characterize the three dimensional charged black hole formation in Einstein–Dilaton gravity. Especially, there is no exact time-dependent solution describing the gravitational collapse to the Chan–Mann charged dilaton black hole. Finally, we discuss the gravitational collapse of a dilaton field in the context of the Cosmic Censorship Conjecture.

Charged fermions tunneling from stationary axially symmetric black holes with generalized uncertainty principle

In this paper, we study the tunneling of charged fermions from the stationary axially symmetric black holes using the generalized uncertainty principle (GUP) via Wentzel, Kramers, and Brillouin (WKB) method. The emission rate of the charged fermions and corresponding modified Hawking temperature of Kerr–Newman black hole, Einstein–Maxwell-dilaton-axion (EMDA) black hole, Kaluza–Klein dilaton black hole, and then, charged rotating black string are obtained and we show that the corrected thermal spectrum is not purely thermal because of the minimal scale length which cause the black hole’s remnant.

Uncertainty relations for quantum coherence in the background of dilaton black holes

The coherence of a quantum system can be considered as the available physical resource, and its quantification respects the choice of reference bases. In this paper, we propose the uncertainty relations for quantum coherence (URQC) of a bipartite system AB in mutually unbiased bases, where particle A is the measured particle and B is regarded as the quantum memory. It is confirmed that the Holevo quantity can improve the lower bound of coherence. By defining the tightness as the difference between coherence and its lower bound, we find that the tightness of the improved URQC is independent of the quantum memory. As an example of application, we investigate the URQC of Dirac particles in the background of a Garfinkle–Horowitz–Strominger dilaton black hole beyond the single-mode approximation. It shows that the lower bound of coherence decreases monotonically with the increase of dilaton parameter due to the Hawking effect. Moreover, since the subsystem A is not affected by the black hole, the tightness of the improved URQC is always keep constant. It worth mentioning that the change of coherence can be precisely predicted via the known tightness and the improved lower bound measured experimentally.

Quasinormal modes of Dirac field in Einstein–Born–Infeld dilaton black hole

The Dirac quasinormal modes of Einstein–Born–Infeld dilaton black holes are studied. We separate the Dirac equation in the curve spacetime into radial and angular parts by Newman–Penrose formalism, and we fortunately obtain the exact analytical solutions of these equations. Then we get the analytical expressions for the quasinormal modes of the black hole. Our results show that the quasinormal frequencies are purely imaginary which means the black hole is very stable. Furthermore, we find that the area spacing of the black hole is described by $$\Delta A_{min}=8\pi \hbar $$ which supports Bekenstein’s conjecture.

Nonlinearly charged scalar-tensor black holes in ( 2+1 ) dimensions

The action of three-dimensional charged Einstein-dilaton gravity theory has been obtained from that of scalar-tensor modified gravity theory by utilizing the suitable conformal transformations. The field equations of the Einstein-dilaton gravity coupled to the power Maxwell nonlinear electrodynamics have been solved and two new classes of static and spherically symmetric charged dilatonic black holes, as the exact solutions to the coupled scalar, electromagnetic and gravitational field equations, have been obtained. Also, the dilaton potential has been written as the linear combination of two Liouville-type potentials. The black hole conserved charges and thermodynamic quantities have been calculated by utilizing the geometrical and thermodynamical methods, separately. The compatibility of the results obtained from these two alternative approaches confirms the validity of the first law of black hole thermodynamics for both of the new black hole solutions in the Einstein frame. A black hole stability or phase transition analysis has been performed in the context of the canonical ensemble. By calculating the black hole heat capacity, with the black hole charge as a constant, the type one and type two phase transition points have been determined. Also, the ranges of the black hole horizon radii at which the Einstein black holes are thermally stable have been identified for both of the new black hole solutions. Then making use of the inverse conformal transformations, two new classes of the scalar-tensor black holes have been obtained from their Einstein frame counterparts. The thermodynamic properties and thermal stability of the new scalar-tensor black holes have been investigated. It has been found that the new charged black holes have the same thermodynamic behaviors in both of the Einstein and Jordan frames.

Superradiance and dynamical evolution of a charged scalar field in an asymptotically anti–de-Sitter dilatonic black hole

We study the dynamics of charged massless scalar fields in asymptotically anti–de Sitter (AdS) dilatonic black holes. The instability of the scalar field, which is triggered by the charged superradiant effect and Dirichlet boundary condition at AdS spatial infinity, can be notably described by exponential growth of the scalar field amplitude in time evolving and unstable quasinormal modes of scalar field perturbation. The numerical computation to demonstrate the superradiant instability of the charged scalar field are performed in the time domain and frequency domain, respectively. We confirm the mode that dominates long time behavior of scalar field matches with quasinormal mode obtained from frequency domain analysis quite well. It is well known the small Reissner-Nordstrom-anti–de Sitter (RN-AdS) black holes are superradiant unstable, while the large RN-AdS black holes are stable against the charged scalar perturbations. According to our numerical results, it is observed that the large dilatonic AdS black holes are also superradiant unstable. At last, we conclude that there exist rapid exponential growing superradiant modes in charged dilatonic AdS black holes, which is significant for the nonlinear dynamical evolution of charged superradiant instability.

Role of Faddeevian anomaly in the s-wave scattering of chiral fermion off dilaton black holes towards preservation of information

It was found that s-wave scattering of chiral fermion off dilaton black-hole when studied with a model generated from the chiral Schwinger model with standard Jackiw-Rajaraman type of anomaly provided information non preserving result. However this scattering problem when studied with a model generated from chiral Schwinger model with generalized Faddeevian type of anomaly rendered information preserving result and it had well agreement with Hawking's revised proposal related to information loss. A minute and equitable investigation in detail has been carried out here to show how Faddeevian type of anomaly scores over the Jackiw-Rajaraman type of anomaly in connection with the s-wave scattering of chiral fermion of dilaton black-hole related to preservation of information.

Holographic entanglement entropy and Van der Waals transitions in Einstein-Maxwell-dilaton theory

According to the gauge/gravity duality, the Van der Waals transition of charged AdS black holes in extended phase space is conjectured to be dual to a renormalization group flow on the space of field theories. So exploring the Van der Waals transition is potentially valuable for studying holographic properties of charged black hole thermodynamics. There are different transition behaviors for charged dilatonic AdS black holes in Einstein-Maxwell-dilaton (EMD) theory with string-inspired potential with different dilaton coupling constants in diverse dimensions. In this work, we find a special class of charged dilatonic AdS black holes which have the standard Van der Waals transition. We study the extended thermodynamics of the special class of black holes, which, in the extremal limit, have near-horizon geometry conformal to AdS$_2 \times S^{D-2}$. We find that, for these black holes, both the pressure-volume transition in fixed charge ensemble and the inverse temperature-entropy transition in fixed pressure ensemble have the standard Van der Waals behaviors. We also find the holographic entanglement entropy undergoes the same transition behaviors for the same critical temperature in fixing the thermodynamic pressure ensemble.

Mathcal{P}\u2013v criticality in gauged supergravities

AdS black holes show richer transition behaviors in extended phase space by assuming the cosmological constant and its conjugate quantity to behave like thermodynamic pressure and thermodynamic volume. We study the extended thermodynamics of charged dilatonic AdS black holes in a class of Einstein–Maxwell-dilaton theories that can be embedded in gauged supergravities in various dimensions. We find that the transition behaviors of higher dimensional dilatonic AdS black holes are different from the four dimensional counterparts, and new transition behaviors emerge in higher dimensions. First, there exists a standard Van der Waals transition only in a five dimensional dilatonic AdS black hole with two equal charges. Second, there emerges a new phase transition branch in negative pressure region in six and seven dimensional dilatonic black holes with two equal charges. Third, there emerge transition behaviors in higher dimensional black hole with single charge cases, which are absent in four dimensions.

Rotating normal and phantom Einstein–Maxwell–dilaton black holes: Geodesic analysis

Depending on five parameters, rotating counterparts of Einstein–Maxwell–dilaton black holes are derived. We discuss their physical and geometric properties and investigate their null and timelike geodesics including circular orbits. The Lense–Thirring effect is considered.

Exact classical and quantum solutions for a covariant oscillator near the black hole horizon in Stueckelberg-Horwitz-Piron theory

We found exact solutions for canonical classical and quantum dynamics for general relativity in Horwitz general covariance theory. These solutions can be obtained by solving the generalized geodesic equation and Schrödinger-Stueckelberg-Horwitz-Piron (SHP) wave equation for a simple harmonic oscillator in the background of a two dimensional dilaton black hole spacetime metric. We proved the existence of an orthonormal basis of eigenfunctions for generalized wave equation. This basis functions form an orthogonal and normalized (orthonormal) basis for an appropriate Hilbert space. The energy spectrum has a mixed spectrum with one conserved momentum p according to a quantum number n. To find the ground state energy we used a variational method with appropriate boundary conditions. A set of mode decomposed wave functions and calculated for the Stueckelberg-Schrodinger equation on a general five dimensional blackhole spacetime in Hamilton gauge.

Topological dyonic dilaton black holes in AdS spaces

We construct a new class of dyonic dilaton black hole solutions in the background of Anti-de Sitter (AdS) spacetime. In order to find an analytical solution which satisfy all the field equations, we should consider the string case where the dilaton coupling is $\alpha=1$. The asymptotic behaviour of the solution ($r\rightarrow\infty$) is exactly AdS, where the dilaton field becomes zero and the metric function reduces to $f(r)\rightarrow -\Lambda r^2/3$. In this spacetime, black hole horizons and cosmological horizons, can be a two-dimensional positive, zero or negative constant curvature surface. We study the physical properties of the solution and show that depending on the metric parameters, these solutions can describe black holes with one or two horizons or a naked singularity. We investigate thermodynamics of the solutions by calculating the charge, mass, temperature, entropy and the electric potential of these solutions and disclose that these conserved and thermodynamic quantities satisfy the first law of black hole thermodynamics. We also analyze thermal stability of the solutions and find the conditions for which we have a stable dyonic dilaton black hole.

Thermodynamics of novel dilatonic BTZ black holes coupled to Born-Infeld electrodynamics

In this work, thermodynamic properties of the three-dimensional charged dilatonic black holes are considered in the presence of Born-Infeld nonlinear electrodynamics. The exact nonlinearly charged black hole solutions to the coupled Einstein-Born-Infeld three-dimensional field equations in the presence of a dilatonic scalar field are constructed. Some new classes of nonlinearly charged dilatonic black hole solutions are distinguished according to different values of the parameters in the theory. The thermodynamics of all of the new Einstein-Born-Infeld-dilaton black holes are studied separately. We show that the thermodynamic quantities satisfy the first law of black hole thermodynamics. Through the canonical ensemble method and noting the black hole heat capacity, we analyze the stability and thermodynamic phase transitions of all of the new Einstein-Born-Infeld-dilaton black holes.

Expanded evasion of the black hole no-hair theorem in dilatonic Einstein-Gauss-Bonnet theory

We study a hairy black hole solution in the dilatonic Einstein-Gauss-Bonnet theory of gravitation, in which the Gauss-Bonnet term is non-minimally coupled to the dilaton field. Hairy black holes with spherical symmetry seem to be easily constructed with a positive Gauss-Bonnet coefficient $\alpha$ within the coupling function, $f(\phi) = \alpha e^{\gamma \phi}$, in an asymptotically flat spacetime, i.e., no-hair theorem seems to be easily evaded in this theory. Therefore, it is natural to ask whether this construction can be expanded into the case with the negative coefficient $\alpha$. In this paper, we present numerically the dilaton black hole solutions with a negative $\alpha$ and analyze the properties of GB term through the aspects of the black hole mass. We construct the new integral constraint allowing the existence of the hairy solutions with the negative $\alpha$. Through this procedure, we expand the evasion of the no-hair theorem for hairy black hole solutions.

Quasinormal modes of static and spherically symmetric black holes with the derivative coupling

We investigate the quasinormal modes of a class of static and spherically symmetric black holes with the derivative coupling. The derivative coupling has rarely been paid attention to the study of black hole quasinormal modes. Specifically, we study the effect of derivative coupling on the quasinormal modes for four kinds of black holes. They are Reissner–Nordström black holes, Bardeen black holes, noncommunicative geometry inspired black holes and dilaton black holes. These black holes are not the solutions of vacuum Einstein equations which guarantees the effect of derivative coupling is not trivial. We find the influence of derivative coupling on the quasinormal modes roughly mimics the overtone numbers. In other words, there is a qualitative similarity in the trend of quasinormal modes frequencies due to increasing either the coupling constant and the overtone number.

Critical behavior of Lifshitz dilaton black holes

Until now, the critical behavior of Lifshitz black holes, in an extended $P\ensuremath{-}v$ space, has not been studied, because it is impossible to find an analytical equation of state, $P=P(v,T)$, for an arbitrary Lifshitz exponent $z$. In this paper, we adopt a new approach toward thermodynamic phase space and successfully explore the critical behavior of ($n+1$)-dimensional Lifshitz dilaton black holes. The most important advantage of this approach is that we keep the cosmological constant as a constant without needing to vary it. For this purpose, we write down the equation of state as ${Q}^{s}={Q}^{s}(T,\mathrm{\ensuremath{\Psi}})$, where $\mathrm{\ensuremath{\Psi}}={(\ensuremath{\partial}M/\ensuremath{\partial}{Q}^{s})}_{S,P}$ is the conjugate of ${Q}^{s}$, and construct a Smarr relation based on this new phase space as $M=M(S,{Q}^{s},P)$, where $s=2p/(2p\ensuremath{-}1)$, with $p$ the power of the power-law Maxwell Lagrangian. We justify such a choice mathematically and show that with this new phase space, the system admits the critical behavior and resembles the van der Waals fluid system when the cosmological constant (pressure) is treated as a fixed parameter, while the charge of the system varies. We obtain the Gibbs free energy of the system and find a swallowtail shape in Gibbs diagrams, which represents the first-order phase transition. Finally, we calculate the critical exponents and show that although thermodynamic quantities depend on the metric parameters such as $z$, $p$, and $n$, the critical exponents are the same as the van der Waals fluid-gas system. This alternative viewpoint of the phase space of a Lifshitz dilaton black hole can be understood easily since one can imagine such a change for a given single black hole, i.e., acquiring charge, which induces the phase transition. Our results further support the viewpoint suggested in [A. Dehyadegari, A. Sheykhi, and A. Montakhab, Phys. Lett. B 768, 235 (2017)].

Spherical accretion by normal and phantom Einstein–Maxwell–dilaton black holes

We investigate the spherical accretion process for general static spherically symmetric fluids. We analyze this process by using the general metric ansatz for spherically symmetric black holes. We specialize to the case of normal and phantom isothermal fluids and investigate their accretion process onto normal and phantom Einstein–Maxwell–dilaton black holes. Backreaction effects are discussed.