Charged fermions tunneling from accelerating and rotating black holes
Energy Technology Data Exchange (ETDEWEB)
Rehman, Mudassar; Saifullah, K., E-mail: mudassir051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-03-01
We study Hawking radiation of charged fermions from accelerating and rotating black holes with electric and magnetic charges. We calculate the tunneling probabilities of incoming and outgoing fermionic particles and find the Hawking temperature of these black holes. We also provide an explicit expression of the classical action for the massive and massless particles in the background of these black holes.
A rotating charged black hole solution in () gravity
Indian Academy of Sciences (India)
Alexis Larrañaga
2012-05-01
In the context of () theories of gravity, we address the problem of ﬁnding a rotating charged black hole solution in the case of constant curvature. A new metric is obtained by solving the ﬁeld equations and we show that its behaviour is typical of a rotating charged source. In addition, we analyse the thermodynamics of the new black hole. The results ensure that the thermodynamical properties in () gravities are qualitatively similar to those of standard General Relativity.
Charged rotating dilaton black holes with Kaluza-Klein asymptotics
Knoll, Christian; Nedkova, Petya
2016-03-01
We construct a class of stationary and axisymmetric solutions to the five-dimensional Einstein-Maxwell-dilaton gravity, which describe configurations of charged rotating black objects with Kaluza-Klein asymptotics. The solutions are constructed by uplifting a vacuum seed solution to six dimensions, performing a boost and a subsequent circle reduction. We investigate the physical properties of the charged solutions and obtain their general relations to the properties of the vacuum seed. We also derive the gyromagnetic ratio and the Smarr-like relations. As particular cases, we study three solutions, which describe a charged rotating black string, a charged rotating black ring on Kaluza-Klein bubbles, and a superposition of two black holes and a Kaluza-Klein bubble.
Entropy bound of horizons for charged and rotating black holes
Directory of Open Access Journals (Sweden)
Wei Xu
2015-06-01
Full Text Available We revisit the entropy product, entropy sum and other thermodynamic relations of charged and rotating black holes. Based on these relations, we derive the entropy (area bound for both event horizon and Cauchy horizon. We establish these results for variant class of 4-dimensional charged and rotating black holes in Einstein(–Maxwell gravity and higher derivative gravity. We also generalize the discussion to black holes with NUT charge. The validity of this formula, which seems to be universal for black holes with two horizons, gives further clue on the crucial role that the thermodynamic relations of multi-horizons play in black hole thermodynamics and understanding the entropy at the microscopic level.
Entropy bound of horizons for charged and rotating black holes
Energy Technology Data Exchange (ETDEWEB)
Xu, Wei, E-mail: xuweifuture@gmail.com [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Jia, E-mail: wangjia2010@mail.nankai.edu.cn [School of Physics, Nankai University, Tianjin 300071 (China); Meng, Xin-he, E-mail: xhm@nankai.edu.cn [School of Physics, Nankai University, Tianjin 300071 (China); State Key Laboratory of Institute of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China)
2015-06-30
We revisit the entropy product, entropy sum and other thermodynamic relations of charged and rotating black holes. Based on these relations, we derive the entropy (area) bound for both event horizon and Cauchy horizon. We establish these results for variant class of 4-dimensional charged and rotating black holes in Einstein(–Maxwell) gravity and higher derivative gravity. We also generalize the discussion to black holes with NUT charge. The validity of this formula, which seems to be universal for black holes with two horizons, gives further clue on the crucial role that the thermodynamic relations of multi-horizons play in black hole thermodynamics and understanding the entropy at the microscopic level.
Shadow of a Charged Rotating Non-Commutative Black Hole
Sharif, M
2016-01-01
This paper investigates the shadow of a charged rotating non-commutative black hole. For this purpose, we first formulate the null geodesics and study the effects of non-commutative charge on the photon orbit. We then explore the effect of spin, angle of inclination as well as non-commutative charge on the silhouette of the shadow. It is found that shape of the shadow deviates from the circle with the decrease in the non-commutative charge. We also discuss observable quantities to study the deformation and distortion in the shadow cast by the black hole which decreases for small values of non-commutative charge. Finally, we study the shadows in the presence of plasma. We conclude that the non-commutativity has a great impact on the black hole shadow.
Shadow of a charged rotating non-commutative black hole
Energy Technology Data Exchange (ETDEWEB)
Sharif, M. [University of the Punjab, Department of Mathematics, Lahore (Pakistan); Pakistan Academy of Sciences, Islamabad (Pakistan); Iftikhar, Sehrish [University of the Punjab, Department of Mathematics, Lahore (Pakistan)
2016-11-15
This paper investigates the shadow of a charged rotating non-commutative black hole. For this purpose, we first formulate the null geodesics and study the effects of a non-commutative charge on the photon orbit. We then explore the effect of spin, angle of inclination as well as non-commutative charge on the silhouette of the shadow. It is found that shape of the shadow deviates from the circle with the decrease in the non-commutative charge. We also discuss observable quantities to study the deformation and distortion in the shadow cast by the black hole which decreases for small values of a non-commutative charge. Finally, we study the shadows in the presence of plasma. We conclude that the non-commutativity has a great impact on the black hole shadow. (orig.)
Rotating Charged Hairy Black Hole in (2+1) Dimensions and Particle Acceleration
Sadeghi, J.; Pourhassan, B.; Farahani, H.
2014-09-01
In this paper, we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.
Rotating charged hairy black hole in (2+1) dimensions and particle acceleration
Sadeghi, J; Farahani, H
2013-01-01
In this paper we construct rotating charged hairy black hole in (2+1) dimensions for infinitesimal black hole charge and rotation parameters. Then we consider this black hole as particle accelerator and calculate the center-of-mass energy of two colliding test particles near the rotating charged hairy black hole in (2+1) dimensions. As we expected, the center-of-mass energy has infinite value.
Charged Rotating AdS Black Holes with Chern-Simons coupling
Mir, Mozhgan
2016-01-01
We obtain a perturbative solution for rotating charged black holes in 5-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant. We start from a small undeformed Kerr-AdS solution and use the electric charge as a perturbative parameter to build up black holes with equal-magnitude angular momenta up to forth order. These black hole solutions are described by three parameters, the charge, horizon radius and horizon angular velocity. We determine the physical quantities of these black holes and study their dependence on the parameters of black holes and arbitrary Chern-Simons coefficient. In particular, for values of CS coupling constant beyond its supergravity amount, due to a rotational instability, counterrotating black holes arise. Also the rotating solutions appear to have vanishing angular momenta and do not manifest uniquely by their global charges.
Hawking Radiation via Damour-Ruffini Method in Squashed Charged Rotating Kaluza-Klein Black Holes
Hu, Ji-Wan; Wu, Jing-He; Liu, Xian-Ming
2017-02-01
Using the Damour-Ruffini method, Hawking radiation of charged particles from squashed charged rotating five-dimensional Kaluza-Klein black holes is investigated extensively. Under the generalized tortoise coordinate transformation, Hawking temperature of the black holes is calculated by using charged scalar particles and Dirac fermions respectively. We find that the obtained Hawking temperature for charged Dirac fermions is the same as for charged scalar particles. What's more, the spectrum of Hawking radiation contains the information of the size of the extra dimension, which could provide insight for further investigation of large extra dimensions in the future.
On Thermodynamical Relation Between Rotating Charged BTZ Black Holes and Effective String Theory
Institute of Scientific and Technical Information of China (English)
Alexis Larra(~n)aga
2008-01-01
In this paper we study the first law of thermodynamics for the (2+1)-dimensional rotating charged BTZ black hole considering a pair of thermodynamical systems constructed with the two horizons of this solution. We show that these two systems are similar to the right and left movers of string theory and that the temperature associated with the black hole is the harmonic mean of the temperatures associated with these two systems.
Universal area product formulas for rotating and charged black holes in four and higher dimensions.
Cvetič, M; Gibbons, G W; Pope, C N
2011-03-25
We present explicit results for the product of all horizon areas for general rotating multicharge black holes, both in asymptotically flat and asymptotically anti-de Sitter spacetimes in four and higher dimensions. The expressions are universal, and depend only on the quantized charges, quantized angular momenta and the cosmological constant. If the latter is also quantized these universal results may provide a "looking glass" for probing the microscopics of general black holes.
Quantum tunneling from the charged non-rotating BTZ black hole with GUP
Sadeghi, Jafar; Reza Shajiee, Vahid
2017-03-01
In the present paper, the quantum corrections to the temperature, entropy and specific heat capacity of the charged non-rotating BTZ black hole are studied by the generalized uncertainty principle in the tunneling formalism. It is shown that quantum corrected entropy would be of the form of predicted entropy in quantum gravity theories like string theory and loop quantum gravity.
Entropy of a rotating and charged black string to all orders in the Planck length
Institute of Scientific and Technical Information of China (English)
Zhao Ren; Wu Yue-Qin; Zhang Li-Chun
2009-01-01
By using the entanglement entropy method, this paper calculates the statistical entropy of the Bose and Fermi fields in thin films, and derives the Bekenstein-Hawking entropy and its correction term on the background of a rotating and charged black string. Here, the quantum field is entangled with quantum states in the black string and thin film to the event horizon from outside the rotating and charged black string. Taking into account the effect of the generalized uncertainty principle on quantum state density, it removes the difficulty of the divergence of state density near the event horizon in the brick-wall model. These calculations and discussions imply that high density quantum states near the event horizon of a black string are strongly correlated with the quantum states in a black string and that black string entropy is a quantum effect. The ultraviolet cut-off in the brick-wall model is not reasonable. The generalized uncertainty principle should be considered in the high energy quantum field near the event horizon. From the viewpoint of quantum statistical mechanics, the correction value of Bekenstein-Hawking entropy is obtained. This allows the fundamental recognition of the correction value of black string entropy at nonspherical coordinates.
Entropy bound of horizons for accelerating, rotating and charged Plebanski-Demianski black hole
Debnath, Ujjal
2016-09-01
We first review the accelerating, rotating and charged Plebanski-Demianski (PD) black hole, which includes the Kerr-Newman rotating black hole and the Taub-NUT spacetime. The main feature of this black hole is that it has 4 horizons like event horizon, Cauchy horizon and two accelerating horizons. In the non-extremal case, the surface area, entropy, surface gravity, temperature, angular velocity, Komar energy and irreducible mass on the event horizon and Cauchy horizon are presented for PD black hole. The entropy product, temperature product, Komar energy product and irreducible mass product have been found for event horizon and Cauchy horizon. Also their sums are found for both horizons. All these relations are dependent on the mass of the PD black hole and other parameters. So all the products are not universal for PD black hole. The entropy and area bounds for two horizons have been investigated. Also we found the Christodoulou-Ruffini mass for extremal PD black hole. Finally, using first law of thermodynamics, we also found the Smarr relation for PD black hole.
Entropy Bound of Horizons for Accelerating, Rotating and Charged Plebanski-Demianski Black Hole
Debnath, Ujjal
2015-01-01
We first review the accelerating, rotating and charged Plebanski-Demianski (PD) black hole, which includes the Kerr-Newman rotating black hole and the Taub-NUT spacetime. The main feature of this black hole is that it has 4 horizons like event horizon, Cauchy horizon and two accelerating horizons. In the non-extremal case, the surface area, entropy, surface gravity, temperature, angular velocity, Komar energy and irreducible mass on the event horizon and Cauchy horizon are presented for PD black hole. The entropy product, temperature product, Komar energy product and irreducible mass product are found for event horizon and Cauchy horizon. Also their sums are also found for both horizons. All these relations are found to be depend on mass of the PD black hole and other parameters. So all the products are not universal for PD black hole. The entropy and area bounds for two horizons are investigated. Also we found the Christodoulou-Ruffini mass for extremal PD black hole. Finally, using first law of thermodynami...
Superradiance and instability of small rotating charged AdS black holes in all dimensions
Energy Technology Data Exchange (ETDEWEB)
Aliev, Alikram N. [Yeni Yuezyil University, Faculty of Engineering and Architecture, Istanbul (Turkey)
2016-02-15
Rotating small AdS black holes exhibit the superradiant instability to low-frequency scalar perturbations, which is amenable to a complete analytic description in four dimensions. In this paper, we extend this description to all higher dimensions, focusing on slowly rotating charged AdS black holes with a single angular momentum. We divide the spacetime of these black holes into the near-horizon and far regions and find solutions to the scalar wave equation in each of these regions. Next, we perform the matching of these solutions in the overlap between the regions, by employing the idea that the orbital quantum number l can be thought of as an approximate integer. Thus, we obtain the complete low-frequency solution that allows us to calculate the complex frequency spectrum of quasinormal modes, whose imaginary part is determined by a small damping parameter. Finally, we find a remarkably instructive expression for the damping parameter, which appears to be a complex quantity in general. We show that the real part of the damping parameter can be used to give a universal analytic description of the superradiant instability for slowly rotating charged AdS black holes in all spacetime dimensions. (orig.)
Thermodynamics of charged rotating dilaton black branes with power-law Maxwell field
Energy Technology Data Exchange (ETDEWEB)
Zangeneh, M.K. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Sheykhi, A.; Dehghani, M.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O.Box 55134-441, Maragha (Iran, Islamic Republic of)
2015-10-15
In this paper, we construct a new class of charged rotating dilaton black brane solutions, with a complete set of rotation parameters, which is coupled to a nonlinear Maxwell field. The Lagrangian of the matter field has the form of the power-law Maxwell field. We study the causal structure of the spacetime and its physical properties in ample details. We also compute thermodynamic and conserved quantities of the spacetime, such as the temperature, entropy, mass, charge, and angular momentum. We find a Smarr-formula for the mass and verify the validity of the first law of thermodynamics on the black brane horizon. Finally, we investigate the thermal stability of solutions in both the canonical and the grand-canonical ensembles and disclose the effects of dilaton field and nonlinearity of the Maxwell field on the thermal stability of the solutions. We find that, for α ≤ 1, charged rotating black brane solutions are thermally stable independent of the values of the other parameters. For α > 1, the solutions can encounter an unstable phase depending on the metric parameters. (orig.)
Thermodynamics of charged rotating dilaton black branes with power-law Maxwell field
Zangeneh, M Kord; Dehghani, M H
2015-01-01
In this paper, we construct a new class of charged rotating dilaton black brane solutions, with complete set of rotation parameters, which is coupled to a nonlinear Maxwell field. The Lagrangian of the matter field has the form of the power-law Maxwell field. We study the casual structure of the spacetime and its physical properties in ample details. We also compute thermodynamic and conserved quantities of the spacetime such as the temperature, entropy, mass, charge, and angular momentum. We find a Smarr-formula for the mass and verify the validity of the first law of thermodynamics on the black brane horizon. Finally, we investigate the thermal stability of solutions in both the canonical and grand canonical ensembles and disclose the effects of the dilaton field on the thermal stability of the solutions. We find that for $\\alpha \\leq 1$, charged rotating black brane solutions are thermally stable independent of the value of the other parameters. For $\\alpha>1$, the solutions can encounter an unstable phase...
Tunnelling of scalar and Dirac particles from squashed charged rotating Kaluza-Klein black holes
Energy Technology Data Exchange (ETDEWEB)
Stetsko, M.M. [Ivan Franko National University of Lviv, Department of Theoretical Physics, Lviv (Ukraine)
2016-02-15
The thermal radiation of scalar particles and Dirac fermions from squashed charged rotating five-dimensional black holes is considered. To obtain the temperature of the black holes we use the tunnelling method. In the case of scalar particles we make use of the Hamilton-Jacobi equation. To consider tunnelling of fermions the Dirac equation was investigated. The examination shows that the radial parts of the action for scalar particles and fermions in the quasi-classical limit in the vicinity of horizon are almost the same and as a consequence it gives rise to identical expressions for the temperature in the two cases. (orig.)
Tunnelling of scalar and Dirac particles from squashed charged rotating Kaluza-Klein black holes
Stetsko, M. M.
2016-02-01
The thermal radiation of scalar particles and Dirac fermions from squashed charged rotating five-dimensional black holes is considered. To obtain the temperature of the black holes we use the tunnelling method. In the case of scalar particles we make use of the Hamilton-Jacobi equation. To consider tunnelling of fermions the Dirac equation was investigated. The examination shows that the radial parts of the action for scalar particles and fermions in the quasi-classical limit in the vicinity of horizon are almost the same and as a consequence it gives rise to identical expressions for the temperature in the two cases.
Dias, O J C; Dias, Oscar J. C.; Lemos, Jose' P. S.
2001-01-01
We obtain static and rotating electrically charged black holes of a Einstein-Maxwell-Dilaton theory of the Brans-Dicke type in (2+1)-dimensions. The theory is specified by three fields, the dilaton, the graviton and the electromagnetic field, and two parameters, the cosmological constant and the Brans-Dicke parameter. It contains eight different cases, of which one distinguishes as special cases, string theory, general relativity and a theory equivalent to four dimensional general relativity with one Killing vector. We find the ADM mass, angular momentum, electric charge and dilaton charge and compute the Hawking temperature of the solutions. Causal structure and geodesic motion of null and timelike particles in the black hole geometries are studied in detail.
Charged Rotating Black Branes in anti-de Sitter Einstein-Gauss-Bonnet Gravity
Dehghani, M H
2003-01-01
We present a new class of charged rotating solutions in the Einstein-Gauss-Bonnet gravity with a negative cosmological constant. These solutions may be interpreted as black brane solutions with two inner and outer event horizons or an extreme black brane depending on the value of the mass parameter $m$. We also find that the Killing vectors are the null generators of the event horizon. The physical properties of the brane such as the temperature, the angular velocity, the entropy, the electric charge and potential are computed. We also compute the action and the Gibbs potential as a function of temperature and angular velocity for the uncharged solutions, and compute the angular momentum and the mass of the black brane through the use of Gibbs potential. We show that these thermodynamic quantities satisfy the first law of thermodynamics. We also perform a local stability analysis of the asymptotically AdS uncharged rotating black brane in various dimensions and show that they are locally stable for the whole ...
Sheykhi, A; Zangeneh, M Kord
2016-01-01
We construct a new class of charged rotating black brane solutions in the presence of logarithmic nonlinear electrodynamics with complete set of the rotation parameters in arbitrary dimensions. The topology of the horizon of these rotating black branes are flat, while, due to the presence of the dilaton field the asymptotic behaviour of them are neither flat nor (anti)-de Sitter [(A)dS]. We investigate the physical properties of the solutions. The mass and angular momentum of the spacetime are obtained by using the counterterm method inspired by AdS/CFT correspondence. We derive temperature, electric potential and entropy associated with the horizon and check the validity of the first law of thermodynamics on the black brane horizon. We study thermal stability of the solutions in both canonical and grand canonical ensemble and disclose the effects of the rotation parameter, nonlinearity of electrodynamics and dilaton field on the thermal stability conditions. We find the solutions are thermally stable for $\\a...
Energy Technology Data Exchange (ETDEWEB)
Herrera-Aguilar, Alfredo [Instituto de FIsica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C-3, Ciudad Universitaria, Morelia, Mich., CP 58040 (Mexico); Nowakowski, Marek [Departamento de FIsica, Universidad de los Andes, Cra. 1 No 18A-10, Santa Fe de Bogota (Colombia)
2004-02-21
Using the stationary formulation of the toroidally compactified heterotic string theory in terms of a pair of matrix Ernst potentials we consider the four-dimensional truncation of this theory with no U(1) vector fields excited. Imposing one timelike Killing vector permits us to express the stationary effective action as a model in which gravity is coupled to a matrix Ernst potential which, under certain parametrization, allows us to interpret the matter sector of this theory as a double Ernst system. We generate a web of string vacua which are related to each other via a set of discrete symmetries of the effective action (some of them involve S-duality transformations and possess non-perturbative character). Some physical implications of these discrete symmetries are analysed and we find that, in some particular cases, they relate rotating black holes coupled to a dilaton with no Kalb-Ramond field, static black holes with non-trivial dilaton and antisymmetric tensor fields, and rotating and static naked singularities. Further, by applying a nonlinear symmetry, namely, the so-called normalized Harrison transformation, on the seed field configurations corresponding to these neutral backgrounds, we recover the U(1){sup n} Abelian vector sector of the four-dimensional action of the heterotic string, charging in this way the double Ernst system which corresponds to each one of the neutral string vacua, i.e., the stationary and the static black holes and the naked singularities.
Blázquez-Salcedo, Jose Luis; Navarro-Lérida, Francisco; Radu, Eugen
2016-01-01
We consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant $\\lambda$. Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magnitude angular momenta, which approach at infinity a globally AdS background. We find that the generic solutions share a number of basic properties with the known Cvetic, L\\"u and Pope black holes which have $\\lambda=1$. New features occur as well, for example, when the Chern-Simons coupling constant exceeds a critical value, the solutions are no longer uniquely determined by their global charges. Moreover, the black holes possess radial excitations which can be labelled by the node number of the magnetic gauge potential function. Solutions with small values of $\\lambda$ possess other distinct features. For instance, the extremal black holes there form two disconnected branches, while not all near-h...
Butterflies with rotation and charge
Reynolds, Alan P.; Ross, Simon F.
2016-11-01
We explore the butterfly effect for black holes with rotation or charge. We perturb rotating BTZ and charged black holes in 2 + 1 dimensions by adding a small perturbation on one asymptotic region, described by a shock wave in the spacetime, and explore the effect of this shock wave on the length of geodesics through the wormhole and hence on correlation functions. We find the effect of the perturbation grows exponentially at a rate controlled by the temperature; dependence on the angular momentum or charge does not appear explicitly. We comment on issues affecting the extension to higher-dimensional charged black holes.
Butterflies with rotation and charge
Reynolds, Alan P
2016-01-01
We explore the butterfly effect for black holes with rotation or charge. We perturb rotating BTZ and charged black holes in 2+1 dimensions by adding a small perturbation on one asymptotic region, described by a shock wave in the spacetime, and explore the effect of this shock wave on the length of geodesics through the wormhole and hence on correlation functions. We find the effect of the perturbation grows exponentially at a rate controlled by the temperature; dependence on the angular momentum or charge does not appear explicitly. We comment on issues affecting the extension to higher-dimensional charged black holes.
Nashed, Gamal G. L.
2016-10-01
We have derived D-dimension rotating charged black-holes with a flat horizon in the framework of Maxwell-Weitzenböck geometry. We have discussed the singularities of these black holes using the invariants of torsion and curvature and shown that the invariants of the torsion have more singularities than those of curvature. To investigate the physics of the derived black holes we have used the Einstein-Cartan geometry to calculate the conserved quantities. From these calculations, we have analyzed the physical meaning of the constants of integration.
Soroushfar, Saheb; Kazempour, Sobhan; Grunau, Saskia; Kunz, Jutta
2016-01-01
We study the geodesic equations in the space time of a rotating charged black hole in $f(R)$ gravity. We derive the equations of motion for test particles and light rays and present their solutions in terms of the Weierstrass $\\wp$, $\\zeta$ and $\\sigma$ functions as well as the Kleinian $\\sigma$ function. With the help of parametric diagrams and effective potentials we analyze the geodesic motion and classify the possible orbit types.
Charged, rotating black objects in Einstein-Maxwell-dilaton theory in $D\\ge 5$
Kleihaus, Burkhard; Radu, Eugen
2016-01-01
We show that the general framework proposed in arXiv:1410.0581 for the study of asymptotically flat vacuum black objects with $k+1$ equal magnitude angular momenta in $D\\geq 5$ spacetime dimensions (with $0\\leq k\\leq \\big[\\frac{D-5}{2} \\big]$) can be extended to the case of Einstein-Maxwell-dilaton (EMd) theory. This framework can describe black holes with spherical horizon topology, the simplest solutions corresponding to a class of electrically charged (dilatonic) Myers-Perry black holes. Balanced charged black objects with $ S^{n+1} \\times S^{2k+1}$ horizon topology can also be studied (with $D=2k+n+4$). Black rings correspond to the case $k=0$, while the solutions with $k>0$ are black ringoids. The basic properties of EMd solutions are discussed for the special case of a Kaluza-Klein value of the dilaton coupling constant. We argue that all features of these solutions can be derived from those of the vacuum seed configurations.
Charged, Rotating Black Objects in Einstein–Maxwell-Dilaton Theory in D ≥ 5
Directory of Open Access Journals (Sweden)
Burkhard Kleihaus
2016-05-01
Full Text Available We show that the general framework proposed by Kleihaus et al. (2015 for the study of asymptotically flat vacuum black objects with k + 1 equal magnitude angular momenta in D ≥ 5 spacetime dimensions (with 0 ≤ k ≤ D - 5 2 can be extended to the case of Einstein–Maxwell-dilaton (EMd theory. This framework can describe black holes with spherical horizon topology, the simplest solutions corresponding to a class of electrically charged (dilatonic Myers–Perry black holes. Balanced charged black objects with S n + 1 × S 2 k + 1 horizon topology can also be studied (with D = 2 k + n + 4 . Black rings correspond to the case k = 0 , while the solutions with k > 0 are black ringoids. The basic properties of EMd solutions are discussed for the special case of a Kaluza–Klein value of the dilaton coupling constant. We argue that all features of these solutions can be derived from those of the vacuum seed configurations.
Tursunov, Arman; Kološ, Martin
2016-01-01
We study motion of charged particles in the field of a rotating black hole immersed into an external asymptotically uniform magnetic field, focusing on the epicyclic quasi-circular orbits near the equatorial plane. Separating the circular orbits into four qualitatively different classes according to the sign of the canonical angular momentum of the motion and the orientation of the Lorentz force, we analyse the circular orbits using the so called force formalism. We find the analytical solutions for the radial profiles of velocity, specific angular momentum and specific energy of the circular orbits in dependence on the black hole dimensionless spin and the magnetic field strength. The innermost stable circular orbits are determined for all four classes of the circular orbits. The stable circular orbits with outward oriented Lorentz force can extend to radii lower than the radius of the corresponding photon circular geodesic. We calculate the frequencies of the harmonic oscillatory motion of the charged parti...
On the near horizon rotating black hole geometries with NUT charges
Energy Technology Data Exchange (ETDEWEB)
Galajinsky, Anton; Orekhov, Kirill [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation)
2016-09-15
The near horizon geometries are usually constructed by implementing a specific limit to a given extreme black hole configuration. Their salient feature is that the isometry group includes the conformal subgroup SO(2, 1). In this work, we turn the logic around and use the conformal invariants for constructing Ricci-flat metrics in d = 4 and d = 5 where the vacuum Einstein equations reduce to a coupled set of ordinary differential equations. In four dimensions the analysis can be carried out in full generality and the resulting metric describes the d = 4 near horizon Kerr-NUT black hole. In five dimensions we choose a specific ansatz whose structure is similar to the d = 5 near horizon Myers-Perry black hole. A Ricci-flat metric involving five arbitrary parameters is constructed. A particular member of this family, which is characterized by three parameters, seems to be a natural candidate to describe the d = 5 near horizon Myers- Perry black hole with a NUT charge. (orig.)
On the near horizon rotating black hole geometries with NUT charges
Galajinsky, Anton; Orekhov, Kirill
2016-09-01
The near horizon geometries are usually constructed by implementing a specific limit to a given extreme black hole configuration. Their salient feature is that the isometry group includes the conformal subgroup SO(2, 1). In this work, we turn the logic around and use the conformal invariants for constructing Ricci-flat metrics in d=4 and d=5 where the vacuum Einstein equations reduce to a coupled set of ordinary differential equations. In four dimensions the analysis can be carried out in full generality and the resulting metric describes the d=4 near horizon Kerr-NUT black hole. In five dimensions we choose a specific ansatz whose structure is similar to the d=5 near horizon Myers-Perry black hole. A Ricci-flat metric involving five arbitrary parameters is constructed. A particular member of this family, which is characterized by three parameters, seems to be a natural candidate to describe the d=5 near horizon Myers-Perry black hole with a NUT charge.
On the near horizon rotating black hole geometries with NUT charges
Galajinsky, Anton
2016-01-01
The near horizon geometries are usually constructed by implementing a specific limit to a given extreme black hole configuration. Their salient feature is that the isometry group includes the conformal subgroup SO(2,1). In this work, we turn the logic around and use the conformal invariants for constructing Ricci-flat metrics in d=4 and d=5 where the vacuum Einstein equations reduce to a coupled set of ordinary differential equations. In four dimensions the analysis can be carried out in full generality and the resulting metric describes the d=4 near horizon Kerr-NUT black hole. In five dimensions we choose a specific ansatz whose structure is similar to the d=5 near horizon Myers-Perry black hole. A Ricci-flat metric involving five arbitrary parameters is constructed. A particular member of this family, which is characterized by three parameters, seems to be a natural candidate to describe the d=5 near horizon Myers-Perry black hole with a NUT charge.
When Charged Black Holes Merge
Kohler, Susanna
2016-08-01
Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge
Dehghani, M. H.; Pourhasan, R.; Mann, R. B.
2011-01-01
We investigate modifications of the Lifshitz black hole solutions due to the presence of Maxwell charge in higher dimensions for arbitrary $z$ and any topology. We find that the behaviour of large black holes is insensitive to the topology of the solutions, whereas for small black holes significant differences emerge. We generalize a relation previously obtained for neutral Lifshitz black branes, and study more generally the thermodynamic relationship between energy, entropy, and chemical pot...
Janis–Newman Algorithm: Generating Rotating and NUT Charged Black Holes
Erbin, Harold
2017-03-01
In this review we present the most general form of the Janis--Newman algorithm. This extension allows to generate configurations which contain all bosonic fields with spin less than or equal to two (real and complex scalar fields, gauge fields, metric field) and with five of the six parameters of the Pleba\\'nski-Demia\\'nski metric (mass, electric charge, magnetic charge, NUT charge and angular momentum). Several examples are included to illustrate the algorithm. We also discuss the extension of the algorithm to other dimensions.
Energy Technology Data Exchange (ETDEWEB)
Bambi, Cosimo, E-mail: bambi@fudan.edu.cn; Modesto, Leonardo, E-mail: lmodesto@fudan.edu.cn
2013-04-25
The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this Letter, we apply the Newman–Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer–Lindquist coordinates. These special solutions are of Petrov type D, they are singularity free, but they violate the weak energy condition for a non-vanishing spin and their curvature invariants have different values at r=0 depending on the way one approaches the origin. We propose a natural prescription to have rotating solutions with a minimal violation of the weak energy condition and without the questionable property of the curvature invariants at the origin.
Bambi, Cosimo
2013-01-01
The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this letter, we apply the Newman-Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer-Lindquist coordinates. These special solutions are of Petrov type ...
Gregory, Ruth; Wills, Danielle
2013-01-01
A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that a such a system displays much richer phenomenology than its static Schwarzschild or Reissner--Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: Large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is con...
Shadow of rotating regular black holes
Abdujabbarov, Ahmadjon; Ahmedov, Bobomurat; Ghosh, Sushant G
2016-01-01
We study the shadows cast by the different types of rotating regular black holes viz. Ay\\'on-Beato-Garc\\'ia {(ABG)}, Hayward, and Bardeen. These black holes have in addition to the total mass ($M$) and rotation parameter ($a$), different parameters as electric charge ($Q$), deviation parameter ($g$), and magnetic charge ($g_{*}$), respectively. Interestingly, the size of the shadow is affected by these parameters in addition to the rotation parameter. We found that the radius of the shadow in each case decreases monotonically and the distortion parameter increases when the value of these parameters increase. A comparison with the standard Kerr case is also investigated. We have also studied the influence of the plasma environment around regular black holes to discuss its shadow. The presence of the plasma affects the apparent size of the regular black hole's shadow to be increased due to two effects (i) gravitational redshift of the photons and (ii) radial dependence of plasma density.
Rotating black holes with non-Abelian hair
Kleihaus, Burkhard; Navarro-Lerida, Francisco
2016-01-01
We here review asymptotically flat rotating black holes in the presence of non-Abelian gauge fields. Like their static counterparts these black holes are no longer uniquely determined by their global charges. In the case of pure SU(2) Yang-Mills fields, the rotation generically induces an electric charge, while the black holes do not carry a magnetic charge. When a Higgs field is coupled, rotating black holes with monopole hair arise in the case of a Higgs triplet, while in the presence of a complex Higgs doublet the black holes carry sphaleron hair. The inclusion of a dilaton allows for Smarr type mass formulae.
Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar
2015-05-01
We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.
Brihaye, Y
2011-01-01
We study the stability of static as well as of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time which possess spherical horizon topology. We observe a non-linear instability related to the condensation of a charged, tachyonic scalar field and construct "hairy" black hole solutions of the full system of coupled Einstein, Maxwell and scalar field equations. We observe that the limiting solution for small horizon radius is either a hairy soliton solution or a singular solution that is not a regular extremal solution. Within the context of the gauge/gravity duality the condensation of the scalar field describes a holographic conductor/superconductor phase transition on the surface of a sphere.
Trova, A.; Karas, V.; Slaný, P.; Kovář, J.
2016-09-01
We present an analytical approach for the equilibrium of a self-gravitating charged fluid embedded in a spherical gravitational and dipolar magnetic fields produced by a central mass. Our scheme is proposed, as a toy model, in the context of gaseous/dusty tori surrounding supermassive black holes in galactic nuclei. While the central black hole dominates the gravitational field and remains electrically neutral, the surrounding material has a non-negligible self-gravitational effect on the torus structure. By charging mechanisms it also acquires non-zero electric charge density, so the two influences need to be taken into account to achieve a self-consistent picture. Using our approach we discuss the impact of self-gravity, represented by the term {d}{{t}} (ratio of the torus total mass to the mass of the central body), on the conditions for existence of the equilibrium and the morphology and typology of the tori. By comparison with a previous work without self-gravity, we show that the conditions can be different. Although the main aim of the present paper is to discuss a framework for the classification of electrically charged, magnetized, self-gravitating tori, we also mention potential astrophysical applications to vertically stratified fluid configurations.
Babichev, Eugeny; Hassaine, Mokhtar
2015-01-01
We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...
Trova, A; Slany, P; Kovar, J
2016-01-01
We present an analytical approach for the equilibrium of a self-gravitating charged fluid embedded in a spherical gravitational and dipolar magnetic fields produced by a central mass. Our scheme is proposed, as a toy-model, in the context of gaseous/dusty tori surrounding supermassive black holes in galactic nuclei. While the central black hole dominates the gravitational field and it remains electrically neutral, the surrounding material has a non-negligible self-gravitational effect on the torus structure. By charging mechanisms it also acquires non-zero electric charge density, so the two influences need to be taken into account to achieve a self-consistent picture. With our approach we discuss the impact of self-gravity, represented by the term dt (ratio of the torus total mass to the mass of the central body), on the conditions for existence of the equilibrium and the morphology and typology of the tori. By comparison with a previous work without self-gravity, we show that the conditions can be different...
On regular rotating black holes
Torres, R.; Fayos, F.
2017-01-01
Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.
Area spectrum of slowly rotating black holes
2010-01-01
We investigate the area spectrum for rotating black holes which are Kerr and BTZ black holes. For slowly rotating black holes, we use the Maggiore's idea combined with Kunstatter's method to derive their area spectra, which are equally spaced.
A nonsingular rotating black hole
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Durban (South Africa)
2015-11-15
The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)
Rotating black hole and quintessence
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag 54001, Durban (South Africa)
2016-04-15
We discuss spherically symmetric exact solutions of the Einstein equations for quintessential matter surrounding a black hole, which has an additional parameter (ω) due to the quintessential matter, apart from the mass (M). In turn, we employ the Newman-Janis complex transformation to this spherical quintessence black hole solution and present a rotating counterpart that is identified, for α = -e{sup 2} ≠ 0 and ω = 1/3, exactly as the Kerr-Newman black hole, and as the Kerr black hole when α = 0. Interestingly, for a given value of parameter ω, there exists a critical rotation parameter (a = a{sub E}), which corresponds to an extremal black hole with degenerate horizons, while for a < a{sub E}, it describes a nonextremal black hole with Cauchy and event horizons, and no black hole for a > a{sub E}. We find that the extremal value a{sub E} is also influenced by the parameter ω and so is the ergoregion. (orig.)
Electric Charge in Interaction with Magnetically Charged Black Holes
Kim, J H
2007-01-01
We examine the angular momentum of an electric charge e placed at rest outside a dilaton black hole with magnetic charge Q. The electromagnetic angular momentum which is stored in the electromagnetic field outside the black hole shows several common features regardless of the dilaton coupling strength, though the dilaton black holes are drastically different in their spacetime structure depending on it. First, the electromagnetic angular momentum depends on the separation distance between the two objects and changes monotonically from eQ to 0 as the charge goes down from infinity to the horizon, if rotational effects of the black hole are discarded. Next, as the black hole approaches extremality, however, the electromagnetic angular momentum tends to be independent of the distance between the two objects. It is then precisely $eQ$ as in the electric charge and monopole system in flat spacetime. We discuss why these effects are exhibited and argue that the above features are to hold in widely generic settings ...
On Hawking Radiation of 3D Rotating Hairy Black Holes
Belhaj, A; Moumni, H EL; Masmar, K; Sedra, M B
2015-01-01
We study the Hawking radiation of 3D rotating hairy black holes. More concretely, we compute the transition probability of a bosonic and fermionic particle in such backgrounds. Thew, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hair B and the rotation parameter a control such a probability.
Einstein-Euler-Heisenberg Theory and Charged Black Holes
Ruffini, Remo; Xue, She-Sheng
2013-01-01
Taking into account the Euler-Heisenberg effective Lagrangian of one-loop nonperturbative Quantum Electrodynamics (QED) contributions, we formulate the Einstein-Euler-Heisenberg theory, and study the solutions of non-rotating black holes with electric and magnetic charges in spherical geometry. In the limit of strong and weak electromagnetic fields of black holes, we calculate the black hole horizon radius, area, and total energy up to the leading order of QED corrections, and discuss the black hole irreducible mass, entropy, and maximally extractable energy as well as the Christodoulou-Ruffini mass formula. We find that these black hole quantities receive the QED corrections, in comparison with their counterparts in the Reissner-Nortstr\\"om solution. The QED corrections show the screening effect on black hole electric charges and the paramagnetic effect on black hole magnetic charges. As a result, the black hole horizon area, irreducible mass, and entropy increase, however the black hole total energy and max...
Stationary Scalar Clouds Around Maximally Rotating Linear Dilaton Black Holes
Sakalli, I
2016-01-01
We investigate the wave dynamics of a charged massive scalar field propagating in a maximally rotating (extremal) linear dilaton black hole geometry. We prove the existence of a discrete and infinite family of resonances describing non-decaying (stationary) scalar configurations (clouds) enclosing these rapidly rotating black holes. The results obtained signal the potential stationary scalar field distributions (dark matter) around the extremal linear dilaton black holes. In particular, we analytically compute the effective height of those clouds above the center of the black hole.
Cardy formula for charged black holes with anisotropic scaling
Bravo-Gaete, Moises; Hassaine, Mokhtar
2015-01-01
We first observe that for Lifshitz black holes whose only charge is the mass, the resulting Smarr relation is a direct consequence of the Lifshitz Cardy formula. From this observation, we propose to extend the Cardy formula to the case of electrically charged Lifshitz black holes satisfying as well a Smarr relation. The expression of our formula depends on the dynamical exponent, the energy and the charge of the ground state which is played by a magnetically charged soliton obtained through a double Wick rotation. The expression also involves a factor multiplying the chemical potentials which varies in function of the electromagnetic theory considered. This factor is precisely the one that appears in the Smarr formula for charged Lifshitz black holes. We test the validity of this Cardy formula in different situations where electrically Lifshitz charged black holes satisfying a Smarr relation are known. We then extend these results to electrically charged black holes with hyperscaling violation. Finally, an ex...
Electroelasticity of Charged Black Branes
Armas, Jay; Obers, Niels A
2013-01-01
We present the first order corrected dynamics of fluid branes carrying higher-form charge by obtaining the general form of their equations of motion to pole-dipole order. Assuming linear response theory, we characterize the corresponding effective theory of stationary bent charged (an)isotropic fluid branes in terms of two sets of response coefficients, the Young modulus and the piezoelectric moduli. We subsequently find large classes of examples in gravity of this effective theory, by constructing stationary strained charged black brane solutions to first order in a derivative expansion. Using solution generating techniques and bent neutral black branes as a seed solution, we obtain a class of charged black brane geometries carrying smeared Maxwell charge in Einstein-Maxwell-dilaton gravity. In the specific case of ten-dimensional space-time we furthermore use T-duality to generate bent black branes with higher-form charge, including smeared D-branes of type II string theory. By subsequently measuring the be...
Particle motion and collisions around rotating regular black hole
Toshmatov, Bobir; Ahmedov, Bobomurat; Stuchlík, Zdenek
2014-01-01
The neutral particle motion around rotating regular black hole that was derived from the Ay\\'{o}n-Beato-Garc\\'{i}a black hole solution by the Newman-Janis algorithm in the preceding paper [Phys. Rev. D 89, 104017, (2014)] has been studied. The dependencies of the ISCO (innermost stable circular orbits along geodesics) and unstable orbits on the value of the electric charge of the rotating regular black hole have been shown. Energy extraction from the rotating regular black hole through various processes has been examined. We have found expression of the center of mass energy for the colliding neutral particles coming from infinity, based on the BSW (Ba\\v{n}ados-Silk-West) mechanism. The electric charge $Q$ of rotating regular black hole decreases the potential of the gravitational field and the particle needs less bound energy at the circular geodesics. This causes the increase of efficiency of the energy extraction through BSW process in the presence of the electric charge $Q$ from rotating regular black hol...
Rotating Black Holes and Coriolis Effect
Wu, Xiaoning; Yuan, Pei-Hung; Cho, Chia-Jui
2015-01-01
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the Petrov-like boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
Rotating black holes and Coriolis effect
Chou, Chia-Jui; Wu, Xiaoning; Yang, Yi; Yuan, Pei-Hung
2016-10-01
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
Rotating black holes and Coriolis effect
Chia-Jui Chou; Xiaoning Wu; Yi Yang; Pei-Hung Yuan
2016-01-01
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the Petrov-like boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black ho...
Rotating black holes and Coriolis effect
Directory of Open Access Journals (Sweden)
Chia-Jui Chou
2016-10-01
Full Text Available In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the suitable boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
Rotating black holes in brane worlds
Frolov, V P; Stojkovic, D B; Frolov, Valeri P.; Fursaev, Dmitri V.; Stojkovic, Dejan
2004-01-01
We study interaction of rotating higher dimensional black holes with a brane in space-times with large extra dimensions. We demonstrate that a rotating black hole attached to a brane can be stationary only if the null Killing vector generating the black hole horizon is tangent to the brane world-sheet. The characteristic time when a rotating black hole with the gravitational radius $r_0$ reaches this final stationary state is $T\\sim r_0^{p-1}/(G\\sigma)$, where $G$ is the higher dimensional gravitational coupling constant, $\\sigma$ is the brane tension, and $p$ is the number of extra dimensions.
Charged Black Holes in New Massive Gravity
Ghodsi, Ahmad; Moghadassi, Mohammad
2010-01-01
We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.
Renormalized vacuum polarization of rotating black holes
Ferreira, Hugo R C
2015-01-01
Quantum field theory on rotating black hole spacetimes is plagued with technical difficulties. Here, we describe a general method to renormalize and compute the vacuum polarization of a quantum field in the Hartle-Hawking state on rotating black holes. We exemplify the technique with a massive scalar field on the warped AdS3 black hole solution to topologically massive gravity, a deformation of (2+1)-dimensional Einstein gravity. We use a "quasi-Euclidean" technique, which generalizes the Euclidean techniques used for static spacetimes, and we subtract the divergences by matching to a sum over mode solutions on Minkowski spacetime. This allows us, for the first time, to have a general method to compute the renormalized vacuum polarization (and, more importantly, the renormalized stress-energy tensor), for a given quantum state, on a rotating black hole, such as the physically relevant case of the Kerr black hole in four dimensions.
Entropy product of rotating black holes in three-dimensions
Mahdavian Yekta, Davood
2017-03-01
It has been shown that the product of the entropies of the inner Cauchy and outer event horizon of the charged axisymmetric and stationary black holes is a universal formula, which is independent of the black hole's mass. In this paper, we investigate this universality for the two kinds of rotating black holes in the three-dimensional gravity models. In fact, we study the spacelike warped anti-de Sitter black hole in the new massive gravity and the Bañados, Teitelboim, and Zanelli black hole in the minimal massive gravity. We show that this rule is held in the first theory. By contrast, in the latter case which includes a holographic gravitational anomalous term, we obtain that the universality does not work and the product depends on the mass. As a complement to the above verification, we also study the thermodynamic properties of these black holes.
Spinning a charged dilaton black hole
Shiraishi, Kiyoshi
2015-01-01
A charged dilaton black hole which possesses infinitesimal angular momentum is studied. We find that the gyromagnetic ratio of the dilaton black hole depends not only on the parameter which appears in the interaction between the dilaton and the electric field but also nonlinearly on the ratio of the charge to the mass of the black hole. The moment of inertia for the charged dilaton hole in the limit of infinitesimal angular momentum is also calculated.
Quantization of rotating linear dilaton black holes
Sakalli, I
2014-01-01
In this paper, we firstly prove that the adiabatic invariant quantity, which is commonly used in the literature for quantizing the rotating black holes (BHs) is fallacious. We then show how its corrected form should be. The main purpose of this paper is to study the quantization of 4-dimensional rotating linear dilaton black hole (RLDBH) spacetime describing with an action, which emerges in the Einstein-Maxwell-Dilaton-Axion (EMDA) theory. The RLDBH spacetime has a non-asymptotically flat (NAF) geometry. They reduces to the linear dilaton black hole (LDBH) metric when vanishing its rotation parameter "a". While studying its scalar perturbations, it is shown that the Schr\\"odinger-like wave equation around the event horizon reduces to a confluent hypergeometric differential equation. Then the associated complex frequencies of the quasinormal modes (QNMs) are computed. By using those QNMs in the true definition of the rotational adiabatic invariant quantity, we obtain the quantum spectra of entropy/area for the...
Angular Momentum-Free of the Entropy Relations for Rotating Kaluza-Klein Black Holes
Liu, Hang; Meng, Xin-he
2017-02-01
Based on a mathematical lemma related to the Vandermonde determinant and two theorems derived from the first law of black hole thermodynamics, we investigate the angular momentum independence of the entropy sum as well as the entropy product of general rotating Kaluza-Klein black holes in higher dimensions. We show that for both non-charged rotating Kaluza-Klein black holes and non-charged rotating Kaluza-Klein-AdS black holes, the angular momentum of the black holes will not be present in entropy sum relation in dimensions d≥4, while the independence of angular momentum of the entropy product holds provided that the black holes possess at least one zero rotation parameter a j = 0 in higher dimensions d≥5, which means that the cosmological constant does not affect the angular momentum-free property of entropy sum and entropy product under the circumstances that charge δ=0. For the reason that the entropy relations of charged rotating Kaluza-Klein black holes as well as the non-charged rotating Kaluza-Klein black holes in asymptotically flat spacetime act the same way, it is found that the charge has no effect in the angular momentum-independence of entropy sum and product in asymptotically flat spactime.
Hawking radiation of scalar particles from accelerating and rotating black holes
Energy Technology Data Exchange (ETDEWEB)
Gillani, Usman A.; Rehman, Mudassar; Saifullah, K., E-mail: mani_precious2001@yahoo.com, E-mail: mudassar051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-06-01
Hawking radiation of uncharged and charged scalar particles from accelerating and rotating black holes is studied. We calculate the tunneling probabilities of these particles from the rotation and acceleration horizons of these black holes. Using this method we recover the correct Hawking temperature as well.
Area-charge inequality for black holes
Dain, Sergio; Reiris, Martín
2011-01-01
The inequality between area and charge $A\\geq 4\\pi Q^2$ for dynamical black holes is proved. No symmetry assumption is made and charged matter fields are included. Extensions of this inequality are also proved for regions in the spacetime which are not necessarily black hole boundaries.
Hydrodynamics and Elasticity of Charged Black Branes
DEFF Research Database (Denmark)
Gath, Jakob
charge and a dilaton coupling. For the case of Maxwell black branes we furthermore compute the charge diffusion constant. We find that the shear viscosity to entropy bound is saturated and comment on proposed bounds for the bulk viscosity to entropy ratio. With the transport coecients we compute......)isotropic uid branes in terms of two sets of response coecients, the Young modulus and the piezoelectric moduli. We subsequently consider a large class of examples in gravity of this effective theory. In particular, we consider dilatonic black p-branes in two different settings: charged under a Maxwell gauge...... as a seed solution, we obtain a class of charged black brane geometries carrying smeared Maxwell charge in Einstein-Maxwell-dilaton theory. In the specific case of ten-dimensional space-time we furthermore use T-duality to generate bent black branes with higher-form charge, including smeared D...
Collision of two general particles around a rotating regular Hayward's black holes
Amir, Muhammed; Ghosh, Sushant G
2016-01-01
The rotating regular Hayward's spacetime, apart from mass ($M$) and angular momentum ($a$), has an additional deviation parameter ($g$) due to the magnetic charge, which generalizes the Kerr black hole when $g\
Angular Momentum-Free of the Entropy Relations for Rotating Kaluza-Klein Black Holes
Liu, Hang
2016-01-01
Based on a mathematical lemma related to the Vandermonde determinant and two theorems derived from the first law of black hole thermodynamics, we investigate the angular momentum independence of the entropy sum as well as the entropy product of general rotating Kaluza-Klein black holes in higher dimensions. We show that for both non-charged rotating Kaluza-Klein black holes and non-charged rotating Kaluza-Klein-AdS black holes, the angular momentum of the black holes will not be present in entropy sum relation in dimensions $d\\geq4$, while the independence of angular momentum of the entropy product holds provided that the black holes possess at least one zero rotation parameter $a_j$ = 0 in higher dimensions $d\\geq5$, which means that the cosmological constant does not affect the angular momentum-free property of entropy sum and entropy product under the circumstances that charge $\\delta=0$. For the reason that the entropy relations of charged rotating Kaluza-Klein black holes as well as the non-charged rotat...
Charged black holes in phantom cosmology
Energy Technology Data Exchange (ETDEWEB)
Jamil, Mubasher; Qadir, Asghar; Rashid, Muneer Ahmad [National University of Sciences and Technology, Center for Advanced Mathematics and Physics, Rawalpindi (Pakistan)
2008-11-15
In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this accretion is possible. This condition restricts the mass-to-charge ratio in a narrow range. This condition also challenges the validity of the cosmic-censorship conjecture since a naked singularity is eventually produced due to accretion of phantom energy onto black hole. (orig.)
Quantization of rotating linear dilaton black holes
Energy Technology Data Exchange (ETDEWEB)
Sakalli, I. [Eastern Mediterranean University, Department of Physics, Mersin 10 (Turkey)
2015-04-15
In this paper, we focus on the quantization of four-dimensional rotating linear dilaton black hole (RLDBH) spacetime describing an action, which emerges in the Einstein-Maxwell-dilaton-axion (EMDA) theory. RLDBH spacetime has a non-asymptotically flat geometry. When the rotation parameter ''a'' vanishes, the spacetime reduces to its static form, the so-called linear dilaton black hole (LDBH) metric. Under scalar perturbations, we show that the radial equation reduces to a hypergeometric differential equation. Using the boundary conditions of the quasinormal modes (QNMs), we compute the associated complex frequencies of the QNMs. In a particular case, QNMs are applied in the rotational adiabatic invariant quantity, and we obtain the quantum entropy/area spectra of the RLDBH. Both spectra are found to be discrete and equidistant, and independent of the a-parameter despite the modulation of QNMs by this parameter. (orig.)
Rotating embedded black holes: Entropy and Hawking's radiation
2004-01-01
In this paper we derive a class of rotating embedded black holes. Then we study Hawking's radiation effects on these embedded black holes. The surface gravity, entropy and angular velocity are given for each of these black holes.
Shadow casted by a twisted and rotating black hole
Chen, Songbai
2016-01-01
Zhang have obtained recently a twisted rotating black hole metric, which is a vacuum solution in four-dimensional Einstein gravity. This black hole solution has a rotation parameter, but without the total angular moment. Here, we have investigated the shadow casted by a twisted rotating black hole. Our results show that the shape of the shadow of the twisted rotating black hole is a standard round disk and does not depend on the inclination angle of the observer. It means that although the twisted rotating black hole has a rotation parameter, its shadow possesses the same behaviors as the common static black hole rather than the usual Kerr-like black holes. Moreover, we find that the marginally circular orbit radius of photon is independent of the direction of photon around the black hole. The value of the marginally circular orbit radius of photon and the size of shadow increase monotonously with the rotation parameter.
`Superresonance' from a rotating acoustic black hole
Basak, S; Basak, Soumen; Majumdar, Parthasarathi
2003-01-01
Using the analogy between a shrinking fluid vortex (`draining bathtub'), modelled as a (2+1) dimensional fluid flow with a sink at the origin, and a rotating (2+1) dimensional black hole with an ergosphere, it is shown that a scalar sound wave is reflected from such a vortex with an {\\it amplification} for a specific range of frequencies of the incident wave, depending on the angular velocity of rotation of the vortex. We discuss the possibility of observation of this phenomenon, especially for inviscid fluids like liquid HeII, where vortices with quantized angular momentum may occur.
Rotating Dilaton Black Strings Coupled to Exponential Nonlinear Electrodynamics
Directory of Open Access Journals (Sweden)
Ahmad Sheykhi
2014-01-01
Full Text Available We construct a new class of charged rotating black string solutions coupled to dilaton and exponential nonlinear electrodynamic fields with cylindrical or toroidal horizons in the presence of a Liouville-type potential for the dilaton field. Due to the presence of the dilaton field, the asymptotic behaviors of these solutions are neither flat nor (AdS. We analyze the physical properties of the solutions in detail. We compute the conserved and thermodynamic quantities of the solutions and verify the first law of thermodynamics on the black string horizon. When the nonlinear parameter β2 goes to infinity, our results reduce to those of black string solutions in Einstein-Maxwell-dilaton gravity.
Central charge for the Schwarzschild black hole
Ropotenko, K.
2016-12-01
Proceeding in exactly the same way as in the derivation of the temperature of a dual CFT for the extremal black hole in the Kerr/CFT correspondence, it is found that the temperature of a chiral, dual CFT for the Schwarzschild black hole is T = 1/2π. Comparing Cardy’s formula with the Bekenstein-Hawking entropy and using T, it is found that the central charge for the Schwarzschild black hole is of the form c = 12Jin, where Jin is the intrinsic angular momentum of the black hole, Jin = A/8πG. It is shown that the central charge for any four-dimensional (4D) extremal black hole is of the same form. The possible universality of this form is briefly discussed.
Rotating black hole solutions with quintessential energy
Toshmatov, Bobir; Ahmedov, Bobomurat
2015-01-01
Quintessential dark energy with density $\\rho$ and pressure $p$ is governed by an equation of state of the form $p=-\\omega_{q}\\rho$ with the quintessential parameter $\\omega_q\\in(-1;-1/3)$. We derive the geometry of quintessential rotating black holes, generalizing thus the Kerr spacetimes. Then we study the quintessential rotating black hole spacetimes with the special value of $\\omega_q = -2/3$ when the resulting formulae are simple and easily tractable. We show that such special spacetimes can exist for dimensionless quintessential parameter $c<1/6$ and determine the critical rotational parameter $a_0$ separating the black hole and naked singularity spacetime in dependence on the quintessential parameter $c$. For the spacetimes with $\\omega_q = 2/3$ we present the integrated geodesic equations in separated form and study in details the circular geodetical orbits. We give radii and parameters of the photon circular orbits, marginally bound and marginally stable orbits. We stress that the outer boundary o...
Noncommutative Geometry Inspired Rotating Black Hole in Three Dimensions
2010-01-01
We find a new rotating black hole in three-dimensional anti-de Sitter space using an anisotropic perfect fluid inspired by the noncommutative black hole. We deduce the thermodynamical quantities of this black hole and compare them with those of a rotating BTZ solution.
Charged black holes in colored Lifshitz spacetimes
Directory of Open Access Journals (Sweden)
Zhong-Ying Fan
2015-04-01
Full Text Available We consider Einstein gravities coupled to a cosmological constant and SU(2 Yang–Mills fields in four and five dimensions. We find that the theories admit colored Lifshitz solutions with dynamic exponents z>1. We study the wave equations of the SU(2 scalar triplet in the bulk, and find that the vacuum color modifies the scaling dimensions of the dual operators. We also introduce a Maxwell field and construct exact solutions of electrically-charged black holes that approach the D=4, z=3 and D=5, z=4 colored Lifshitz spacetimes. We derive the thermodynamical first law for general colored and charged Lifshitz black holes.
The Foaming Three-Charge Black Hole
Bena, Iosif; Wang, Chih-Wei; Nicholas P. Warner(Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, U.S.A.)
2006-01-01
We find a very large set of smooth horizonless geometries that have the same charges and angular momenta as the five-dimensional, maximally-spinning, three-charge, BPS black hole (J^2 = Q^3). Our solutions are constructed using a four-dimensional Gibbons-Hawking base space that has a very large number of two-cycles. The entropy of our solutions is proportional to Q^(1/2). In the same class of solutions we also find microstates corresponding to zero-entropy black rings, and these are related t...
Hydrodynamics of R-charged black holes
Son, D T; Son, Dam T.; Starinets, Andrei O.
2006-01-01
We consider hydrodynamics of N=4 supersymmetric SU(N_c) Yang-Mills plasma at a nonzero density of R-charge. In the regime of large N_c and large 't Hooft coupling the gravity dual description involves an asymptotically Anti- de Sitter five-dimensional charged black hole solution of Behrnd, Cvetic and Sabra. We compute the shear viscosity as a function of chemical potentials conjugated to the three U(1) \\subset SO(6)_R charges. The ratio of the shear viscosity to entropy density is independent of the chemical potentials and is equal to 1/4\\pi. For a single charge black hole we also compute the thermal conductivity, and investigate the critical behavior of the transport coefficients near the boundary of thermodynamic stability.
BSW process of the slowly evaporating charged black hole
Wang, Liancheng; He, Feng; Fu, Xiangyun
2015-01-01
In this paper, we study the BSW process of the slowly evaporating charged black hole. It can be found that the BSW process will also arise near black hole horizon when the evaporation of charged black hole is very slow. But now the background black hole does not have to be an extremal black hole, and it will be approximately an extremal black hole unless it is nearly a huge stationary black hole.
Superradiance Instability of Small Rotating AdS Black Holes in Arbitrary Dimensions
Delice, Özgür
2015-01-01
We investigate the stability of $D$ dimensional singly rotating Myers-Perry-AdS black holes under superradiance against scalar field perturbations. It is well known that small four dimensional rotating or charged AdS black holes are unstable against superradiance instability of a scalar field. Recent works extended the existence of this instability to five dimensional rotating charged AdS black holes or static charged AdS Black holes in arbitrary dimensions. In this work we analytically prove that, rotating small AdS black holes in arbitrary dimensions also show superradiance instability irrespective of the value of the (positive) angular momentum quantum number. To do this we solve the Klein-Gordon equation in the slow rotation, low frequency limit. By using the asymptotic matching technique, we are able to calculate the real and imaginary parts of the correction terms to the frequency of the scalar field due to the presence of the black hole, confirming the presence of superradiance instability. We see that...
Noether charge, black hole volume and complexity
Couch, Josiah; Nguyen, Phuc H
2016-01-01
In this paper, we study the physical significance of the thermodynamic volumes of black holes along two different, but complementary, directions. In the first half of the paper, we make use of the Iyer-Wald charge formalism to compute the volume of a particularly hairy black hole. Our computation clarifies and explains existing results, and serves as a prototype for computations of this kind for complicated black hole solutions. In the second half of the paper, we establish a connection between the extended thermodynamics and the Brown et al's "complexity=action" proposal. We show that, in a broad class of AdS black holes, the thermodynamic volume arises as the late-time rate of growth of the bulk action evaluated on the Wheeler-deWitt patch.
Retrolensing by a charged black hole
Tsukamoto, Naoki; Gong, Yungui
2017-03-01
Compact objects with a light sphere such as black holes and wormholes can reflect light rays like a mirror. This gravitational lensing phenomenon is called retrolensing and it is an interesting tool to survey dark and compact objects with a light sphere near the solar system. In this paper, we calculate the deflection angle analytically in the strong deflection limit in the Reissner-Nordström spacetime without Taylor expanding it in the power of the electric charge. Using the obtained deflection angle in the strong deflection limit, we investigate the retrolensing light curves and the separation of double images by the light sphere of Reissner-Nordström black holes.
Black hole horizons and quantum charged particles
Jaramillo, José Luis
2014-01-01
We point out a structural similarity between the characterization of black hole apparent horizons as stable marginally outer trapped surfaces (MOTS) and the quantum description of a non-relativistic charged particle moving in given magnetic and electric fields on a closed surface. Specifically, the spectral problem of the MOTS-stability operator corresponds to a stationary quantum particle with a formal fine-structure constant $\\alpha$ of negative sign. We discuss how such analogy enriches both problems, illustrating this with the insights into the MOTS-spectral problem gained from the analysis of the spectrum of the quantum charged particle Hamiltonian.
Noncommutative geometry-inspired rotating black hole in three dimensions
Indian Academy of Sciences (India)
Juan Manuel Tejeiro; Alexis Larrañaga
2012-01-01
We ﬁnd a new rotating black hole in three-dimensional anti-de Sitter space using an anisotropic perfect ﬂuid inspired by the noncommutative black hole. We deduce the thermodynamical quantities of this black hole and compare them with those of a rotating BTZ solution and give corrections to the area law to get the exact nature of the Bekenstein–Hawking entropy.
Instability of charged anti-de Sitter black holes
Gwak, Bogeun; Lee, Bum-Hoon; Ro, Daeho
2016-10-01
We have studied the instability of charged anti-de Sitter black holes in four- or higher-dimensions under fragmentation. The unstable black holes under fragmentation can be broken into two black holes. Instability depends not only on the mass and charge of the black hole but also on the ratio between the fragmented black hole and its predecessor. We have found that the near extremal black holes are unstable, and Schwarzschild-AdS black holes are stable. These are qualitatively similar to black holes in four dimensions and higher. The detailed instabilities are numerically investigated.
Canonical Entropy and Phase Transition of Rotating Black Hole
Institute of Scientific and Technical Information of China (English)
ZHAO Ren; WU Yue-Qin; ZHANG Li-Chun
2008-01-01
Recently, the Hawking radiation of a black hole has been studied using the tunnel effect method. The radiation spectrum of a black hole is derived. By discussing the correction to spectrum of the rotating black hole, we obtain the canonical entropy. The derived canonical entropy is equal to the sum of Bekenstein-Hawking entropy and correction term. The correction term near the critical point is different from the one near others. This difference plays an important role in studying the phase transition of the black hole. The black hole thermal capacity diverges at the critical point. However, the canonical entropy is not a complex number at this point. Thus we think that the phase transition created by this critical point is the second order phase transition. The discussed black hole is a five-dimensional Kerr-AdS black hole. We provide a basis for discussing thermodynamic properties of a higher-dimensional rotating black hole.
Entropy/Area spectra of the charged black hole from quasinormal modes
Wei, Shao-Wen; Yang, Ke; Zhong, Yuan
2010-01-01
With the new physical interpretation of quasinormal modes proposed by Maggiore, the quantum area spectra of black holes have been investigated recently. It is shown that, the area spectrum for a non-rotating black hole with no charge is equidistant. While, for a rotating black hole, it is non-equidistant and depends on the angle momentum $J$. So, it is worth to investigate the area spectrum for a charged black hole. Following the Kunstatter's method, we obtain the area spectrum and entropy spectrum of the charged Garfinkle-Horowitz-Strominger black hole, originated from the effective action that emerges in the low-energy of string theory. Both the area spectrum and entropy spectrum are found to be equally spaced and do not depend on the charge $q$, which is different from that of the rotating black hole. Combing with possible observational data from gravity waves, we hope our results can give us answers to the open questions such as the black hole entropy.
Stability of accretion disk around rotating black holes
Mukhopadhyay, B
2004-01-01
I discuss the stability of accretion disks when the black hole is considered to be rotating. I show, how the fluid properties get changed for different choices of angular momentum of black holes. I treat the problem in pseudo-Newtonian approach with a suitable potential from Kerr geometry. When the angular momentum of a black hole is considered to be significant, the valid disk parameter region affects and a disk may become unstable. Also the possibility of shock in an accretion disk around rotating black holes is checked. When the black hole is chosen to be rotating, the sonic locations of the accretion disk get shifted or disappear, making the disk unstable by means of loosing entropy. To bring the disk in a stable situation, the angular momentum of the accreting matter has to be reduced/enhanced (for co/counter-rotating disk) by means of some physical process.
Penrose process in a charged axion-dilaton coupled black hole
Energy Technology Data Exchange (ETDEWEB)
Ganguly, Chandrima [University of Cambridge, Department of Applied Mathematics and Theoretical Physics, Cambridge (United Kingdom); SenGupta, Soumitra [Indian Association for the Cultivation of Science, Department of Theoretical Physics, Kolkata (India)
2016-04-15
Using the Newman-Janis method to construct the axion-dilaton coupled charged rotating black holes, we show that the energy extraction from such black holes via the Penrose process takes place from the axion/Kalb-Ramond field energy responsible for rendering the angular momentum to the black hole. Determining the explicit form for the Kalb-Ramond field strength, which is argued to be equivalent to spacetime torsion, we demonstrate that at the end of the energy extraction process, the spacetime becomes torsion free with a spherically symmetric non-rotating black hole remnant. In this context, applications to physical phenomena, such as the emission of neutral particles in astrophysical jets, are also discussed. It is seen that the infalling matter gains energy from the rotation of the black hole, or equivalently from the axion field, and that it is ejected as a highly collimated astrophysical jet. (orig.)
Black hole solutions in Einstein-charged scalar field theory
Ponglertsakul, Supakchai; Winstanley, Elizabeth
2015-01-01
We investigate possible end-points of the superradiant instability for a charged black hole with a reflecting mirror. By considering a fully coupled system of gravity and a charged scalar field, hairy black hole solutions are obtained. The linear stability of these black hole solutions is studied.
Stability of the extremal Reissner-Nordstrom black hole to charged scalar perturbations
Hod, Shahar
2013-01-01
The stability of Reissner-Nordstrom black holes to neutral (gravitational and electromagnetic) perturbations was established almost four decades ago. However, the stability of these charged black holes under charged perturbations has remained an open question due to the well-known phenomena of superradiant scattering: A charged scalar field impinging on a charged Reissner-Nordstrom black hole can be amplified as it scatters off the hole. If the incident field has a non-zero rest mass, then the mass term effectively works as a mirror, preventing the energy extracted from the hole from escaping to infinity. One may suspect that such superradiant amplification of charged fields in Reissner-Nordstrom spacetimes may lead to an instability of these charged black holes (in as much the same way that rotating Kerr black holes are unstable under rotating scalar perturbations). However, we show here that, for extremal Reissner-Nordstrom black holes, the two conditions which are required in order to trigger a possible su...
Stability of charged black holes in string theory under charged massive scalar perturbations
Li, Ran
2013-01-01
Similar to the superradiant effect in Reissner-Nordstr\\"{o}m black hole, a charged scalar field can be amplified when impinging on the charged black hole in string theory. According to the black-hole bomb mechanism, the mass term of the incident field can effectively works as the reflecting mirror, which may trigger the instability of black hole. We study the possible instability triggered by superradiant effect and demonstrate that the charged black hole in string theory is stable against the massive charged scalar perturbation. The reason is that there is no trapping potential well in the black hole exterior and there is no bound states in the superradiant regime.
On The Phase Structure and Thermodynamic Geometry of R-Charged Black Holes
Sahay, Anurag; Sengupta, Gautam
2010-01-01
We study the phase structure and equilibrium state space geometry of R-charged black holes in $D = 5$, 4 and 7 and the corresponding rotating $D3$, $M2$ and $M5$ branes. For various charge configuratins of the compact black holes in the canonical ensemble we demonstrate new liquid-gas like phase coexistence behaviour culminating in second order critical points. The critical exponents turn out to be the same as that of four dimensional asymptotically AdS black holes in Einstein Maxwell theory. We further establish that the regions of stability for R-charged black holes are, in some cases, more constrained than is currently believed, due to properties of some of the response coefficients. The equilibrium state space scalar curvature is calculated for various charge configurations, both for the case of compact as well as flat horizons and its asymptotic behaviour with temperature is established.
Sakalli, I.
2016-10-01
Charged massive scalar field perturbations are studied in the gravitational, electromagnetic, dilaton, and axion fields of rotating linear dilaton black holes. In this geometry, we separate the covariant Klein-Gordon equation into radial and angular parts and obtain the exact solutions of both the equations in terms of the confluent Heun functions. Using the radial solution, we study the problems of resonant frequencies, entropy/area quantization, and greybody factor. We also analyze the behavior of the wave solutions near the event horizon of the rotating linear dilaton black hole and derive its Hawking temperature via the Damour-Ruffini-Sannan method.
Cosmic censorship of rotating Anti-de Sitter black hole
Gwak, Bogeun; Lee, Bum-Hoon
2016-02-01
We test the validity of cosmic censorship in the rotating anti-de Sitter black hole. For this purpose, we investigate whether the extremal black hole can be overspun by the particle absorption. The particle absorption will change the mass and angular momentum of the black hole, which is analyzed using the Hamilton-Jacobi equations consistent with the laws of thermodynamics. We have found that the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid.
Energy extraction from Kerr black holes by rigidly rotating strings
Kinoshita, Shunichiro; Tanabe, Kentaro
2016-01-01
In this paper, we show that a rigidly rotating string can extract the rotational energy from a rotating black hole. We consider Nambu-Goto strings stationary with respect to a co-rotating Killing vector with an uniform angular velocity $\\omega$ in the Kerr spacetime. We show that a necessary condition of the energy-extraction process is that an effective horizon on the string worldsheet, which corresponds to the inner light surface, is inside the ergosphere of the Kerr black hole and the angular velocity $\\omega$ is less than that of the black hole $\\Omega_\\mathrm{h}$. Furthermore, we discuss global configurations of such strings in both of a slow-rotation limit and the extremal Kerr case.
Soroushfar, Saheb; Saffari, Reza; Sahami, Ehsan
2016-07-01
In this paper, we consider the timelike and null geodesics around the static (GMGHS, magnetically charged GMGHS, electrically charged GMGHS) and the rotating (Kerr-Sen dilaton-axion) dilaton black holes. The geodesic equations are solved in terms of Weierstrass elliptic functions. To classify the trajectories around the black holes, we use the analytical solution and effective potential techniques and then characterize the different types of the resulting orbits in terms of the conserved energy and angular momentum. Also, using the obtained results we study astrophysical applications.
Stationary charged scalar clouds around black holes in string theory
Bernard, Canisius
2016-10-01
It was reported that Kerr-Newman black holes can support linear charged scalar fields in their exterior regions. These stationary massive charged scalar fields can form bound states, which are called stationary scalar clouds. In this paper, we show that Kerr-Sen black holes can also support stationary massive charged scalar clouds by matching the near- and far-region solutions of the radial part of the Klein-Gordon wave equation. We also review stationary scalar clouds within the background of static electrically charged black hole solutions in the low-energy limit of heterotic string field theory, namely, the Gibbons-Maeda-Garfinkle-Horowitz-Strominger black holes.
Stationary Charged Scalar Clouds around Black Holes in String Theory
Bernard, Canisius
2016-01-01
It was reported that Kerr-Newman black holes can support linear charged scalar field in their exterior regions. This stationary massive charged scalar field can form a bound-state and these bound-states are called stationary scalar clouds. In this paper, we study that Kerr-Sen black holes can also support stationary massive charged scalar clouds by matching the near and far region solutions of the radial part of Klein-Gordon wave equation. We also review stationary scalar clouds within the background of static electrically charged black hole solution in the low energy limit of heterotic string field theory namely the GMGHS black holes.
Particle rotational trapping on a floating electrode by rotating induced-charge electroosmosis.
Ren, Yukun; Liu, Weiyu; Liu, Jiangwei; Tao, Ye; Guo, Yongbo; Jiang, Hongyuan
2016-09-01
We describe a novel rotating trait of induced-charge electroosmotic slip above a planar metal surface, a phenomenon termed "Rotating induced-charge electro-osmosis" (ROT-ICEO), in the context of a new microfluidic technology for tunable particle rotation or rotational trap. ROT-ICEO has a dynamic flow stagnation line (FSL) that rotates synchronously with a background circularly polarized electric field. We reveal that the rotating FSL of ROT-ICEO gives rise to a net hydrodynamic torque that is responsible for rotating fluids or particles in the direction of the applied rotating electric field either synchronously or asynchronously, the magnitude of which is adjusted by a balance between rotation of FSL and amplitude of angular-direction flow component oscillating at twice the field frequency. Supported by experimental observation, our physical demonstration with ROT-ICEO proves invaluable for the design of flexible electrokinetic framework in modern microfluidic system.
Rotating Black Holes on Kaluza-Klein Bubbles
Tomizawa, S; Mishima, T; Iguchi, Hideo; Mishima, Takashi; Tomizawa, Shinya
2007-01-01
Using the solitonic solution generating techniques, we generate a new exact solution which describes a pair of rotating black holes on a Kaluza-Klein bubble as a vacuum solution in the five-dimensional Kaluza-Klein theory. We also investigate the properties of this solution. Two black holes with topology S^3 are rotating along the same direction and the bubble plays a role in holding two black holes. In static case, it coincides with the solution found by Elvang and Horowitz.
Shapes of rotating nonsingular black hole shadows
Amir, Muhammed
2016-01-01
It is a belief that singularities are creation of general relativity and hence in the absence of a quantum gravity, models of nonsingular black hole have received significant attention. We study the shadow (apparent shape), an optical appearance because of its strong gravitational field, cast by a nonsingular black hole which is characterized by three parameters, i.e., mass ($M$), spin ($a$) and a deviation parameter ($k$). The nonsingular black hole, under consideration, is a generalization of the Kerr black hole can be recognized asymptotically ($r>>k, k>0$) explicitly as the Kerr\\(-\\)Newman black hole, and in the limit $k \\rightarrow 0$ as the Kerr black hole. It turns out that the shadow of a nonsingular black hole is a dark zone covered by deformed circle. Interestingly, it is seen that the shadow of a black hole is affected due to the parameter $k$. Indeed, for a given $a$, the size of a shadow reduces as the parameter $k$ increases and the shadow becomes more distorted as we increase the value of the p...
Rotating black holes pierced by a cosmic string
Kubiznak, David
2015-01-01
A rotating black hole threaded by an infinitely long cosmic string is studied in the framework of the Abelian Higgs model. We show that contrary to a common belief in the presence of rotation the backreaction of the string does not induce a simple conical deficit. This leads to new distinct features of the Kerr--string system such as modified ISCO or shifted ergosphere, though these effects are most likely outside the range of observational precision. For an extremal rotating black hole, the system exhibits a first-order phase transition for the gravitational Meissner effect: small black holes exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon, whereas the horizon of large black holes is pierced by the vortex. A brief review prepared for the MG14 Proceedings.
Interaction of higher-dimensional rotating black holes with branes
Frolov, V P; Stojkovic, D B; Frolov, Valeri P.; Fursaev, Dmitri V.; Stojkovic, Dejan
2004-01-01
We study interaction of rotating higher dimensional black holes with a brane in space-times with large extra dimensions. We demonstrate that in a general case a rotating black hole attached to a brane can loose bulk components of its angular momenta. A stationary black hole can have only those components of the angular momenta which are connected with Killing vectors generating transformations preserving a position of the brane. In a final stationary state the null Killing vector generating the black hole horizon is tangent to the brane. We discuss first the interaction of a cosmic string and a domain wall with the 4D Kerr black hole. We then prove the general result for slowly rotating higher dimensional black holes interacting with branes. The characteristic time when a rotating black hole with the gravitational radius $r_0$ reaches this final stationary state is $T\\sim r_0^{p-1}/(G\\sigma)$, where $G$ is the higher dimensional gravitational coupling constant, $\\sigma$ is the brane tension, and $p$ is the nu...
Rotating black holes with scalar hair in three dimensions
Zou, De-Cheng; Wang, Bin; Xu, Wei
2014-01-01
We examine the first law of thermodynamics in (2+1)-dimensional rotating hairy black holes and find that the first law of black hole thermodynamics can be protected when the scalar field parameter $B$ is constrained to relate to the black hole size. We disclose the Hawking-Page phase transition between the hairy black holes and the pure thermal radiation. Moreover, we find that the free energies of the rotating hairy black holes depend on the ratio between the horizon size to the scalar field parameter $B$. We also compare the free energies for the hairy black hole and the BTZ black hole when they have the same temperature and angular momentum, and find that when this ratio is large, the BTZ black hole has smaller free energy which is a thermodynamically more preferred phase; but when the ratio is small, the hairy black hole has smaller free energy and there exists the possibility for the BTZ black hole to dress up scalar field and become hairy.
Phantom Energy Accretion by a Stringy Charged Black Hole
Institute of Scientific and Technical Information of China (English)
M.Sharif; G.Abbas
2012-01-01
We investigate the dynamical behavior of phantom energy near a stringy magnetically charged black hole. For this purpose, we derive equations of motion for steady-state spherically symmetric Row of phantom energy onto the stringy magnetically charged black hole. It is found that phantom energy accreting onto a black hole decreases its mass. Further, the location of the critical points of accretion is explored, which yields a mass to charge ratio. This ratio implies that accretion process cannot transform a black hole into an extremal black hole or a naked singularity, hence cosmic censorship hypothesis remains valid here.%We investigate the dynamical behavior of phantom energy near a stringy magnetically charged black hole.For this purpose,we derive equations of motion for steady-state spherically symmetric flow of phantom energy onto the stringy magnetically charged black hole.It is found that phantom energy accreting onto a black hole decreases its mass.Further,the location of the critical points of accretion is explored,which yields a mass to charge ratio.This ratio implies that accretion process cannot transform a black hole into an extremal black hole or a naked singularity,hence cosmic censorship hypothesis remains valid here.
Harrison transformation and charged black objects in Kaluza-Klein theory
Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen; Stelea, Cristian
2009-09-01
We generate charged black brane solutions in D-dimensions in a theory of gravity coupled to a dilaton and an antisymmetric form, by using a Harrison-type transformation. The seed vacuum solutions that we use correspond to uplifted Kaluza-Klein black strings and black holes in (D-p)-dimensions. A generalization of the Marolf-Mann quasilocal formalism to the Kaluza-Klein theory is also presented, the global charges of the black objects being computed in this way. We argue that the thermodynamics of the charged solutions can be derived from that of the vacuum configurations. Our results show that all charged Kaluza-Klein solutions constructed by means of Harrison transformations are thermodynamically unstable in a grand canonical ensemble. The general formalism is applied to the case of nonuniform black strings and caged black hole solutions in D = 5,6 Einstein-Maxwell-dilaton gravity, whose geometrical properties and thermodynamics are discussed. We argue that the topology changing transition scenario, which was previously proposed in the vacuum case, also holds in this case. Spinning generalizations of the charged black strings are constructed in six dimensions in the slowly rotating limit. We find that the gyromagnetic ratio of these solutions possesses a nontrivial dependence on the nonuniformity parameter.
Charged scalar perturbations around Garfinkle–Horowitz–Strominger black holes
Directory of Open Access Journals (Sweden)
Cheng-Yong Zhang
2015-10-01
Full Text Available We examine the stability of the Garfinkle–Horowitz–Strominger (GHS black hole under charged scalar perturbations. Employing the appropriate numerical methods, we show that the GHS black hole is always stable against charged scalar perturbations. This is different from the results obtained in the de Sitter and anti-de Sitter black holes. Furthermore, we argue that in the GHS black hole background there is no amplification of the incident charged scalar wave to cause the superradiance, so that the superradiant instability cannot exist in this spacetime.
Black Holes with Multiple Charges and the Correspondence Principle
Yang, H
1998-01-01
We consider the entropy of near extremal black holes with multiple charges in the context of the recently proposed correspondence principle of Horowitz and Polchinski, including black holes with two, three and four Ramond-Ramond charges. We find that at the matching point the black hole entropy can be accounted for by massless open strings ending on the D-branes for all cases except a black hole with four Ramond-Ramond charges, in which case a possible resolution in terms of brane-antibrane excitations is considered.
A black ring with a rotating 2-sphere
Energy Technology Data Exchange (ETDEWEB)
Figueras, Pau [Departament de Fisica Fonamental (Mexico); C.E.R. en AstrofIsica, Fisica de Particules i Cosmologia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)
2005-07-01
We present a solution of the vacuum Einstein's equations in five dimensions corresponding to a black ring with horizon topology S{sup 1} x S{sup 2} and rotation in the azimuthal direction of the S{sup 2}. This solution has a regular horizon up to a conical singularity, which can be placed either inside the ring or at infinity. This singularity arises due to the fact that this black ring is not balanced. In the infinite radius limit we correctly reproduce the Kerr black string, and taking another limit we recover the Myers-Perry black hole with a single angular momentum.
Strong field gravitational lensing by a charged Galileon black hole
Zhao, Shan-Shan
2016-01-01
Strong field gravitational lensings are dramatically disparate from those in the weak field by representing relativistic images due to light winds one to infinity loops around a lens before escaping. We study such a lensing caused by a charged Galileon black hole, which is expected to have possibility to evade no-hair theorem. We calculate the angular separations and time delays between different relativistic images of the charged Galileon black hole. All these observables can potentially be used to discriminate a charged Galileon black hole from others. We estimate the magnitudes of the observables for the closest suppermassive black hole Sgr A*. It is found that when the scalar filed in the Galileon is weakly coupled to the gravitational field and it is "low-speed", the charged Galileon black hole can possibly be distinguished from a Reissner-Nordstr\\"om black hole.
On uniqueness of charged Kerr-AdS black holes in five dimensions
Madden, O; Madden, Owen; Ross, Simon F.
2004-01-01
We show that the solutions describing charged rotating black holes in five-dimensional gauged supergravities found recently by Cvetic, Lu and Pope [hep-th/0406196,hep-th/0407058] are completely specified by the mass, charges and angular momentum. The additional parameter appearing in these solutions is removed by a coordinate transformation and redefinition of parameters. Thus, the apparent hair in these solutions is unphysical.
Instability of Charged Anti-de Sitter Black Holes
Gwak, Bogeun; Ro, Daeho
2015-01-01
We study the instability of charged anti-de Sitter black holes in four or higher-dimension under fragmentation. The instability of fragmentation breaks the black hole into two black holes. We have found that the region near extremal or massive black holes become unstable under fragmentation. These regions depend not only on the mass and charge of initial black hole but also those of the fragmented one. The instability in higher-dimension is qualitatively similar to that of four-dimension. The detailed instabilities are numerically investigated.
Quantum field theory on rotating black hole spacetimes
Ferreira, Hugo R C
2015-01-01
This thesis is concerned with the development of a general method to compute renormalised local observables for quantum matter fields, in a given quantum state, on a rotating black hole spacetime. The rotating black hole may be surrounded by a Dirichlet mirror, if necessary, such that a regular, isometry-invariant vacuum state can be defined. We focus on the case of a massive scalar field on a (2+1)-dimensional rotating black hole, but the method can be extended to other types of matter fields and higher-dimensional rotating black holes. The Feynman propagator of the matter field in the regular, isometry-invariant state is written as a sum over mode solutions on the complex Riemannian section of the black hole. A Hadamard renormalisation procedure is implemented at the level of the Feynman propagator by expressing its singular part as a sum over mode solutions on the complex Riemannian section of rotating Minkowski spacetime. This allows us to explicitly renormalise local observables such as the vacuum polari...
Physics of Rotating and Expanding Black Hole Universe
Directory of Open Access Journals (Sweden)
Seshavatharam U. V. S.
2010-04-01
Full Text Available Throughout its journey universe follows strong gravity. By unifying general theory of relativity and quantum mechanics a simple derivation is given for rotating black hole's temperature. It is shown that when the rotation speed approaches light speed temperature approaches Hawking's black hole temperature. Applying this idea to the cosmic black hole it is noticed that there is "no cosmic temperature" if there is "no cosmic rotation". Starting from the Planck scale it is assumed that universe is a rotating and expanding black hole. Another key assumption is that at any time cosmic black hole rotates with light speed. For this cosmic sphere as a whole while in light speed rotation "rate of decrease" in temperature or "rate of increase" in cosmic red shift is a measure of "rate of cosmic expansion". Since 1992, measured CMBR data indicates that, present CMB is same in all directions equal to $2.726^circ$ K, smooth to 1 part in 100,000 and there is no continuous decrease! This directly indicates that, at present rate of decrease in temperature is practically zero and rate of expansion is practically zero. Universe is isotropic and hence static and is rotating as a rigid sphere with light speed. At present galaxies are revolving with speeds proportional to their distances from the cosmic axis of rotation. If present CMBR temperature is $2.726^circ$ K, present value of obtained angular velocity is $2.17 imes 10^{-18}$ rad/sec $cong$ 67 Km/sec$imes$Mpc. Present cosmic mass density and cosmic time are fitted with a $ln (volume ratio$ parameter. Finally it can be suggested that dark matter and dark energy are ad-hoc and misleading concepts.
Black hole Area-Angular momentum-Charge inequality in dynamical non-vacuum spacetimes
Clément, María E Gabach
2011-01-01
We show that the area-angular momentum-charge inequality (A/(4\\pi))^2 \\geq (2J)^2 + (Q_E^2 + Q_M^2)^2 holds for apparent horizons of electrically and magnetically charged rotating black holes in generic dynamical and non-vacuum spacetimes. More specifically, this quasi-local inequality applies to axially symmetric closed outermost stably marginally (outer) trapped surfaces, embedded in non-necessarily axisymmetric black hole spacetimes with non-negative cosmological constant and matter content satisfying the dominant energy condition.
GUP Assisted Hawking Radiation of Rotating Acoustic Black Holes
Sakalli, I; Jusufi, K
2016-01-01
Recent studies [J. Steinhauer, Nature Phys., $\\textbf{10}$, 864 (2014); Phys. Rev. D $\\textbf{92}$, 024043 (2015)] provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
GUP assisted Hawking radiation of rotating acoustic black holes
Sakalli, I.; Övgün, A.; Jusufi, K.
2016-10-01
Recent studies (Steinhauer in Nat. Phys. 10:864, 2014, Phys. Rev. D 92:024043, 2015) provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
Quantum Gravity Effects On Charged Micro Black Holes Thermodynamics
Abbasvandi, N; Radiman, Shahidan; Abdullah, W A T Wan
2016-01-01
The charged black hole thermodynamics is corrected in terms of the quantum gravity effects. Most of the quantum gravity theories support the idea that near the Planck scale, the standard Heisenberg uncertainty principle should be reformulated by the so-called Generalized Uncertainty Principle (GUP) which provides a perturbation framework to perform required modifications of the black hole quantities. In this paper, we consider the effects of the minimal length and maximal momentum as GUP type I and the minimal length, minimal momentum, and maximal momentum as GUP type II on thermodynamics of the charged TeV-scale black holes. We also generalized our study to the universe with the extra dimensions based on the ADD model. In this framework, the effect of the electrical charge on thermodynamics of the black hole and existence of the charged black hole remnants as a potential candidate for the dark matter particles are discussed.
Physics of Rotating and Expanding Black Hole Universe
Directory of Open Access Journals (Sweden)
Seshavatharam U. V. S.
2010-04-01
Full Text Available Throughout its journey universe follows strong gravity. By unifying general theory of relativity and quantum mechanics a simple derivation is given for rotating black hole’s temperature. It is shown that when the rotation speed approaches light speed temperature approaches Hawking’s black hole temperature. Applying this idea to the cosmic black hole it is noticed that there is “no cosmic temperature” if there is “no cosmic rotation”. Starting from the Planck scale it is assumed that- universe is a rotating and expanding black hole. Another key assumption is that at any time cosmic black hole rotates with light speed. For this cosmic sphere as a whole while in light speed rotation “rate of decrease” in temperature or “rate of increase” in cosmic red shift is a measure of “rate of cosmic expansion”. Since 1992, measured CMBR data indicates that, present CMB is same in all directions equal to 2 : 726 K ; smooth to 1 part in 100,000 and there is no continuous decrease! This directly indicates that, at present rate of decrease in temperature is practically zero and rate of expansion is practically zero. Universe is isotropic and hence static and is rotating as a rigid sphere with light speed. At present galaxies are revolving with speeds proportional to their distances from the cosmic axis of rotation. If present CMBR temperature is 2 : 726 K, present value of obtained angular velocity is 2 : 17 10 Present cosmic mass density and cosmic time are fitted with a ln ( volume ratio parameter. Finally it can be suggested that dark matter and dark energy are ad-hoc and misleading concepts.
Dynamics of test particles in the five-dimensional, charged, rotating EMCS spacetime
Reimers, Stephan
2016-01-01
We derive the complete set of geodesic equations for massive and massless test particles of a five-dimensional, charged, rotating black hole solution of the Einstein-Maxwell-Chern-Simons field equations in five-dimensional minimal gauged supergravity and present their analytical solutions in terms of Weierstra{\\ss}' elliptic functions. We study the polar and radial motion, depending on the black hole and test particle parameters, and characterize the test particle motion qualitatively by the means of effective potentials. We use the analytical solutions in order to visualize the test particle motion by two- and three-dimensional plots.
General relativistic magnetohydrodynamic simulations of collapsars: Rotating black hole cases
Energy Technology Data Exchange (ETDEWEB)
Mizuno, Y. [Kyoto Univ., Kyoto (Japan). Department of Astronomy; Yamada, S. [Waseda Univ., Tokyo (Japan). Science and Engineering; Koide, S. [Toyama Univ., Toyama (Japan). Department of Engineering; Shibata, K. [Kyoto Univ., Kyoto (Japan). Kwasan and Hida Observatory
2005-06-01
We have performed 2.5-dimensional general relativistic magnetohydrodynamic (MHD) simulations of coIIapsars including a rotating black hole. InitiaIIy, we assume that the care collapse has failed in this star. A rotating black hole of a few solar masses is inserted by hand into the calculation. The simulation results show the formation of a diskIike structure and the generation of a jetIike outflow near the central black hole. The jetIike outflow propagates and accelerated mainly by the magnetic field. The total jet velocity is {approx} 0.3c. When the rotation of the black hole is faster, the magnetic field is twisted strongly owing to the frame-dragging effect. The magnetic energy stored by the twisting magnetic field is directly converted to kinetic energy of the jet rather than propagating as an Alfven wave. Thus, as the rotation of the black hole becomes faster, the poloidal velocity of the jet becomes faster.
Quantum backreaction on a rotating BTZ black hole
Casals, Marc; Martínez, Cristián; Zanelli, Jorge
2016-01-01
We investigate semiclassical backreaction on a rotating BTZ black hole geometry produced by a conformally coupled quantum scalar field. We obtain the backreacted metric in analytic form. This allows us to explore the quantum effects on various regions of relevance for a rotating black hole space-time. We find that for given values of mass and angular momentum, quantum effects lead to a growth of both the event horizon and the radius of the ergosphere, and to a reduction of the angular velocity, compared to the unperturbed values. Furthermore, quantum effects give rise to the formation of a curvature singularity at the Cauchy horizon but show no evidence of a superradiant instability.
Null geodesics in a magnetically charged stringy black hole spacetime
Kuniyal, Ravi Shankar; Uniyal, Rashmi; Nandan, Hemwati; Purohit, K. D.
2016-04-01
We study the null geodesics of a four-dimensional magnetic charged black hole spacetime arising in string theory. The behaviour of effective potential in view of the different values of black hole parameters are analysed in the equatorial plane. The possible orbits for null geodesics are also discussed in view of the different values of the impact parameter. We have also calculated the frequency shift of photons in this spacetime. The results are compared to those obtained for the electrically charged stringy black hole spacetime and the Schwarzschild black hole spacetime in general relativity.
Effect of Thermal Fluctuations on a Charged Dilatonic Black Saturn
Pourhassan, Behnam
2016-01-01
In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.
Effect of thermal fluctuations on a charged dilatonic black Saturn
Directory of Open Access Journals (Sweden)
Behnam Pourhassan
2016-04-01
Full Text Available In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.
Radiation spectrum of a high-dimensional rotating black hole
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
This study extends the classical Damour-Ruffini method and discusses Hawking radiation in a (n + 4)-dimensional rotating black hole. Under the condition that the total energy and angular momentum of spacetime are conservative, but angular momentum a = J/M of unit mass of the black hole is variable, taking into consideration the reaction of the radiation of the particle to the spacetime, a new Tortoise coordinate transformation and discuss the black hole radiation spectrum is discussed. The radiation spectrum that satisfies the unitary principle in the general case is derived.
Conserved Charges and First Law of Thermodynamics for Kerr-de Sitter Black Holes
Hajian, Kamal
2016-01-01
Recently, a general formulation for calculating conserved charges for (black hole) solutions to generally covariant gravitational theories, in any dimensions and with arbitrary asymptotic behaviors has been introduced. Equipped with this method, which can be dubbed as "solution phase space method," we calculate mass and angular momentum for the Kerr-dS black hole. Then, for any choice of horizons, associated entropy and the first law of thermodynamics are derived. Interestingly, according to insensitivity of the analysis to the chosen cosmological constant, the analysis unifies the thermodynamics of rotating stationary black holes in 4 (and other) dimensions with either AdS, flat or dS asymptotics. We extend the analysis to include electric charge, i.e. to the Kerr-Newman-dS black hole.
State-space Manifold and Rotating Black Holes
Bellucci, Stefano
2010-01-01
We study a class of fluctuating higher dimensional black hole configurations obtained in string theory/ $M$-theory compactifications. We explore the intrinsic Riemannian geometric nature of Gaussian fluctuations arising from the Hessian of the coarse graining entropy, defined over an ensemble of brane microstates. It has been shown that the state-space geometry spanned by the set of invariant parameters is non-degenerate, regular and has a negative scalar curvature for the rotating Myers-Perry black holes, Kaluza-Klein black holes, supersymmetric $AdS_5$ black holes, $D_1$-$D_5$ configurations and the associated BMPV black holes. Interestingly, these solutions demonstrate that the principal components of the state-space metric tensor admit a positive definite form, while the off diagonal components do not. Furthermore, the ratio of diagonal components weakens relatively faster than the off diagonal components, and thus they swiftly come into an equilibrium statistical configuration. Novel aspects of the scali...
Transient Instability of Rapidly Rotating Black Holes
Gralla, Samuel E; Zimmerman, Peter
2016-01-01
We analytically study the linear response of a near-extremal Kerr black hole to external scalar, electromagnetic, and gravitational field perturbations. We show that the energy density, electromagnetic field strength, and tidal force experienced by infalling observers exhibit transient growth near the horizon. The growth lasts arbitrarily long in the extremal limit, reproducing the horizon instability of extremal Kerr. We explain these results in terms of near-horizon geometry and discuss potential astrophysical implications.
Extreme Gravitational Lensing near Rotating Black Holes
Beckwith, K; Beckwith, Kris; Done, Chris
2004-01-01
We describe a new approach to calculating photon trajectories and gravitational lensing effects in the strong gravitational field of the Kerr black hole. These techniques are applied to explore both the imaging and spectral properties of photons that perform multiple orbits of the central mass before escaping to infinity. Viewed at large inclinations, these higher order photons contribute $\\sim 20 %$ of the total luminosity of the system for a Schwarzschild hole, whilst for an extreme Kerr black hole this fraction rises to $\\sim 60 %$. In more realistic models these photons will be re-absorbed by the disc at large distances from the hole, but this returning radiation could provide a physical mechanism to resolve the discrepancy between the predicted and observed optical/UV colours in AGN. Conversely, at low inclinations, higher order images re-intercept the disc plane close to the black hole, so need not be absorbed by the disc if this is within the plunging region. These photons form a bright ring carrying a...
Electrically charged Kerr black holes with scalar hair
Delgado, Jorge F M; Radu, Eugen; Runarsson, Helgi
2016-01-01
We construct electrically charged Kerr black holes (BHs) with scalar hair. Firstly, we take an uncharged scalar field, interacting with the electromagnetic field only indirectly, via the background metric. The corresponding family of solutions, dubbed Kerr-Newman BHs with ungauged scalar hair, reduces to (a sub-family of) Kerr-Newman BHs in the limit of vanishing scalar hair and to uncharged rotating boson stars in the limit of vanishing horizon. It adds one extra parameter to the uncharged solutions: the total electric charge. This leading electromagnetic multipole moment is unaffected by the scalar hair and can be computed by using Gauss's law on any closed 2-surface surrounding (a spatial section of) the event horizon. By contrast, the first sub-leading electromagnetic multipole -- the magnetic dipole moment --, gets suppressed by the scalar hair, such that the gyromagnetic ratio is always smaller than the Kerr-Newman value ($g=2$). Secondly, we consider a gauged scalar field and obtain a family of Kerr-Ne...
Loop variables in the geometry of a rotating black string
De Carvalho, A M M; Furtado, C; Furtado, Claudio; Moraes, Fernando
2003-01-01
In this paper we analyze in the Wilson loop context the parallel transport of vectors and spinors around a closed loop in the background space-time of a rotating black string in order to classify its global properties. We also examine particular closed orbits in this space-time and verify the Mandelstam relations.
Rotating Black Holes and the Kerr Metric
Kerr, Roy Patrick
2008-10-01
Since it was first discovered in 1963 the Kerr metric has been used by relativists as a test-bed for conjectures on worm-holes, time travel, closed time-like loops, and the existence or otherwise of global Cauchy surfaces. More importantly, it has also used by astrophysicists to investigate the effects of collapsed objects on their local environments. These two groups of applications should not be confused. Astrophysical Black Holes are not the same as the Kruskal solution and its generalisations.
Analytic continuation of the rotating black hole state counting
Achour, Jibril Ben; Perez, Alejandro
2016-01-01
In loop quantum gravity, a spherical black hole can be described in terms of a Chern-Simons theory on a punctured 2-sphere. The sphere represents the horizon. The punctures are the edges of spin-networks in the bulk which cross the horizon and carry quanta of area. One can generalize this construction and model a rotating black hole by adding an extra puncture colored with the angular momentum J in the 2-sphere. We compute the entropy of rotating black holes in this model and study its semi-classical limit. After performing an analytic continuation which sends the Barbero-Immirzi parameter to +/- i, we show that the leading order term in the semi-classical expansion of the entropy reproduces the Bekenstein-Hawking law independently of the value of J.
Horizon structure of rotating Einstein-Born-Infeld black holes and shadow
Energy Technology Data Exchange (ETDEWEB)
Atamurotov, Farruh [Institute of Nuclear Physics, Tashkent (Uzbekistan); Inha University in Tashkent, Tashkent (Uzbekistan); Ulugh Beg Astronomical Institute, Tashkent (Uzbekistan); National University of Uzbekistan, Tashkent (Uzbekistan); Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of Kwa-Zulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Private Bag 54001, Durban (South Africa); Ahmedov, Bobomurat [Institute of Nuclear Physics, Tashkent (Uzbekistan); Ulugh Beg Astronomical Institute, Tashkent (Uzbekistan); National University of Uzbekistan, Tashkent (Uzbekistan)
2016-05-15
We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the Born-Infeld parameter goes to infinity (β → ∞). We find that for a given β, mass M, and charge Q, there exist a critical spinning parameter a{sub E} and r{sub H}{sup E}, which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and a{sub E} decreases and r{sub H}{sup E} increases with increase of the Born-Infeld parameter β, while a < a{sub E} describes a non-extremal Einstein-Born-Infeld black hole with outer and inner horizons. Similarly, the effect of β on the infinite redshift surface and in turn on the ergo-region is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational field. We also investigate the shadow cast by the both static and rotating Einstein-Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated, which allows us to investigate the shadow cast by a black hole which is found to be a dark zone covered by a circle. Interestingly, the shadow of an Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole, which consists of concentric circles, for different values of the Born-Infeld parameter β, whose radius decreases with increase of the value of the parameter β. Finally, we have studied observable distortion parameter for shadow of the rotating Einstein-Born-Infeld black hole. (orig.)
Thermodynamics of rotating black holes and black rings: phase transitions and thermodynamic volume
Altamirano, Natacha; Mann, Robert B; Sherkatghanad, Zeinab
2014-01-01
In this review we summarize, expand, and set in context recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. We specifically consider the thermodynamics of higher-dimensional rotating asymptotically flat and AdS black holes and black rings in a canonical (fixed angular momentum) ensemble. We plot the associated thermodynamic potential-the Gibbs free energy-and study its behaviour to uncover possible thermodynamic phase transitions in these black hole spacetimes. We show that the multiply-rotating Kerr-AdS black holes exhibit a rich set of interesting thermodynamic phenomena analogous to the "every day thermodynamics" of simple substances, such as reentrant phase transitions of multicomponent liquids, multiple first-order solid/liquid/gas phase transitions, and liquid/gas phase transitions of the Van der Waals type. Furthermore, the reentrant phase tran...
Quantum loop corrections of charged dS black hole
Naji, J
2016-01-01
In this paper, a charged black hole in de Sitter space considered and logarithmic corrected entropy used to study thermodynamics. Logarithmic corrections of entropy comes from thermal fluctuations which plays role of quantum loop corrections. In that case we are able to study the effect of quantum loop on the black hole thermodynamics and statistics. As black hole is a gravitational object, so it helps to obtain some information about the quantum gravity.
The Mixed Phase of Charged AdS Black Holes
Directory of Open Access Journals (Sweden)
Piyabut Burikham
2016-01-01
Full Text Available We study the mixed phase of charged AdS black hole and radiation when the total energy is fixed below the threshold to produce a stable charged black hole branch. The coexistence conditions for the charged AdS black hole and radiation are derived for the generic case when radiation particles carry charge. The phase diagram of the mixed phase is demonstrated for both fixed potential and charge ensemble. In the dual gauge picture, they correspond to the mixed phase of quark-gluon plasma (QGP and hadron gas in the fixed chemical potential and density ensemble, respectively. In the nuclei and heavy-ion collisions at intermediate energies, the mixed phase of exotic QGP and hadron gas could be produced. The mixed phase will condense and evaporate into the hadron gas as the fireball expands.
Energy Technology Data Exchange (ETDEWEB)
Ibohal, Ng [Department of Mathematics, Manipur University, Imphal 795003, Manipur (India)
2002-08-21
In this paper variably-charged non-rotating Reissner-Nordstrom and rotating Kerr-Newman black holes are discussed. Such a variable charge e with respect to the polar coordinate r in the field equations is referred to as an electrical radiation of the black hole. It is shown that every electrical radiation e(r) of the non-rotating black hole leads to a reduction in its mass M by some quantity. If one considers such electrical radiation taking place continuously for a long time, then a continuous reduction of the mass may take place in the black-hole body and the original mass of the black hole may be evaporated completely. At that stage, the gravity of the object may depend only on the electromagnetic field, not on the mass. Immediately after the complete evaporation of the mass, if the next radiation continues, there may be creation of a new mass leading to the formation of a negative mass naked singularity. It appears that this new mass of the naked singularity would never decrease, but might increase gradually as the radiation continues forever. A similar investigation is also discussed in the case of a variably-charged rotating Kerr-Newman black hole. Thus, it has been shown by incorporating Hawking's evaporation of radiating black holes in the form of spacetime metrics, every electrical radiation of variably-charged rotating and non-rotating black holes may produce a change in the mass of the body without affecting the Maxwell scalar.
Thermodynamics and Phase Transition in Rotational Kiselev Black Hole
Xu, Zhaoyi
2016-01-01
We calculate the thermodynamical features of rotational Kiselev black holes, specifically we use one order approximate of horizon to calculate thermodynamical features for all $\\omega$. The thermodynamics features include areas, entropies, horizon radii, surface gravities, surface temperatures, Komar energies and irreducible masses at the Cauchy horizon and Event horizon. At the same time the products of these features have been discussed. We find that the products are independent with mass of black hole and determined by $\\omega$ and $\\alpha$. The features in the situations of $\\omega=-2/3,1/3$ and $0$ (quintessence matter, radiation and dust) have been discussed in detail. We also generalize the Smarr mass formula and Christodoulou-Ruffini mass formula to these black holes. Finally we study the phase transition for black holes with different $\\omega$ and obtain the state equation. We analyze the phase transition for $\\omega=1/3$, and find that $\\alpha$ shifts the critical point of phase transition.
Quasilocal Energy for Static Charged Black Holes in String Theory
Institute of Scientific and Technical Information of China (English)
WANG Shi-Liang; JING Ji-Liang; WANG Yong-Jiu
2001-01-01
The Brown-York quasilocal energies of some static charged dilaton black holes are calculated, and then the validity of Martinez's conjecture is explored in string theory. It is shown that the energy is positive and monotonically decreases to the ADM mass at spatial infinity, and the conjecture that the Brown-York quasilocal energy at the outer horizon of black hole reduces to twice of its irreducible mass is still applicable for the static charged black holes in string theory. The result is different from Bose-Naing's one.``
Internal Structure of Charged AdS Black Holes
Bhattacharjee, Srijit; Virmani, Amitabh
2016-01-01
When an electrically charged black hole is perturbed its inner horizon becomes a singularity, often referred to as the Poisson-Israel mass inflation singularity. Ori constructed a model of this phenomenon for asymptotically flat black holes, in which the metric can be determined explicitly in the mass inflation region. In this paper we implement the Ori model for charged AdS black holes. We find that the mass function inflates faster than the flat space case as the inner horizon is approached. Nevertheless, the mass inflation singularity is still a weak singularity: although spacetime curvature becomes infinite, tidal distortions remain finite on physical objects attempting to cross it.
Thermodynamics and Geometrothermodynamics of Charged black holes in Massive Gravity
Suresh, Jishnu; Prabhakar, Geethu; Kuriakose, V C
2016-01-01
The objective of this paper is to study the thermodynamics and thermodynamic geometry of charged de-Sitter and charged anti de-Sitter black hole solutions in massive gravity. In this study, the presence of a negative cosmological constant is identified as a thermodynamic variable, the pressure. By incorporating this idea, we study the effect of curvature parameter as well as the mass of graviton in the thermodynamics of the black hole system. We further extend our studies to different topology of the space time and its effects on phase transition and thermodynamics. In addition, the phase transition structure of the black hole and its interactions are reproduced using geometrothermodynamics.
Charged Stringy Black Holes With Non-Abelian Hair
Donets, E E
1993-01-01
Static spherically symmetric asymptotically flat charged black hole solutions are constructed within the magnetic SU(3) sector of the 4-dimensional heterotic string effective action. They possess non-abelian hair in addition to the Coulomb magnetic field and are qualitatively similar to the Einstein-Yang-Mills colored SU(3) black holes except for the extremal case. In the extremality limit the horizon shrinks and the resulting geometry around the origin coincides with that of an extremal abelian dilatonic black hole with magnetic charge. Non-abelian hair exibits then typical sphaleron structure.
Massless black holes and charged wormholes in string theory
Goulart, Prieslei
2016-01-01
We present the zero mass black holes and charged Einstein-Rosen bridges (wormholes) that arise from the five parameters dyonic black hole solution of the Einstein-Maxwell-dilaton theory. These massless black holes exist individually in spacetime, different from the known massless solutions which come in pairs with opposite signs for their masses. By imposing appropriate boundary conditions the massless solution can be nonextremal, extremal or a naked singularity. The nonextremal and extremal massless solutions allow the bridge construction, and from them we obtain the first analytical charged Einstein-Rosen bridge satisfying the null energy condition ever found.
An Electrically charged doubly spinning dipole black ring
Rocha, J.V.; Rodriguez, M.J.; Varela Rizo, O. M.
2012-01-01
We present a new asymptotically flat, doubly spinning black ring of D = 5 Einstein-Maxwell-dilaton theory with Kaluza-Klein dilaton coupling. Besides the mass and two angular momenta, the solution displays both electric charge and (magnetic) dipole charge. The class of solutions that are free from c
Stuchlík, Zdeněk
2015-01-01
To test the role of large-scale magnetic fields in accretion processes, we study dynamics of charged test particles in vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes od the charged particle dynamics provides mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is larg...
Direct imaging rapidly-rotating non-Kerr black holes
Energy Technology Data Exchange (ETDEWEB)
Bambi, Cosimo, E-mail: Cosimo.Bambi@physik.uni-muenchen.de [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universitaet Muenchen, 80333 Munich (Germany); Caravelli, Francesco, E-mail: fcaravelli@perimeterinstitute.ca [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, 14476 Golm (Germany); Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Modesto, Leonardo, E-mail: lmodesto@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada)
2012-05-01
Recently, two of us have argued that non-Kerr black holes in gravity theories different from General Relativity may have a topologically non-trivial event horizon. More precisely, the spatial topology of the horizon of non-rotating and slow-rotating objects would be a 2-sphere, like in Kerr space-time, while it would change above a critical value of the spin parameter. When the topology of the horizon changes, the black hole central singularity shows up. The accretion process from a thin disk can potentially overspin these black holes and induce the topology transition, violating the Weak Cosmic Censorship Conjecture. If the astrophysical black hole candidates are not the black holes predicted by General Relativity, we might have the quite unique opportunity to see their central region, where classical physics breaks down and quantum gravity effects should appear. Even if the quantum gravity region turned out to be extremely small, at the level of the Planck scale, the size of its apparent image would be finite and potentially observable with future facilities.
Correction value to charged Bekenstein-Hawking black hole entropy
Institute of Scientific and Technical Information of China (English)
2008-01-01
Recently,based on the study of black hole Hawking radiation with the tunnel effect method,we found that the radiation spectrum of the black hole is not a strict pure thermal spectrum. It is a very interesting problem to determine how the departure of the black hole radiation spectrum from the pure thermal spectrum affects entropy. We calculate the partition function by the energy spectrum obtained using tunnel effect. Using the relation between the partition function and entropy,we derive the correction value to Bekenstein-Hawking entropy of the charged black hole. Fur-thermore,we obtain the conditions that various thermodynamic quantities must satisfy,when phase transition of the charged black hole occurs.
Dynamics in the Charged Time Conformal Schwarzschild Black Hole
Jawad, Abdul; Shahzad, M Umair; Abbas, G
2016-01-01
In this work, we present the new technique for discussing the dynamical motion of neutral as well as charged particles in the absence/presence of magnetic field around the time conformal Schwarzschild black hole. Initially, we find the numerical solutions of geodesics of Schwarzschild black hole and the time conformal Schwarzschild black hole. We observe that the Schwarzschild spacetime admits the time conformal factor $e^{\\epsilon f(t)}$, where $f(t)$ is an arbitrary function and $\\epsilon$ is very small which causes the perturbation in the spacetimes. This technique also re-scale the energy content of spacetime. We also investigate the thermal stability, horizons and energy conditions corresponding time conformal Schwarzschild spacetime. Also, we examine the dynamics of neutral and charged particle around time conformal Schwarzschild black hole. We investigate the circumstances under which the particle can escape from vicinity of black hole after collision with another particle. We analyze the effective pot...
Non-singular rotating black hole with a time delay in the center
De Lorenzo, Tommaso; Speziale, Simone
2015-01-01
As proposed by Bambi and Modesto, rotating non-singular black holes can be constructed via the Newman-Janis algorithm. Here we show that if one starts with a modified Hayward black hole with a time delay in the centre, the algorithm succeeds in producing a rotating metric, but curvature divergences reappear. To preserve finiteness, the time delay must be introduced directly at the level of the non-singular rotating metric. This is possible thanks to the deformation of the inner stationarity limit surface caused by the regularisation, and in more than one way. We outline three different possibilities, distinguished by the angular velocity of the event horizon. Along the way, we provide additional results on the Bambi-Modesto rotating Hayward metric, such as the structure of the regularisation occurring at the centre, the behaviour of the quantum gravity scale alike an electric charge in decreasing the angular momentum of the extremal black hole configuration, or details on the deformation of the ergosphere.
Dyonic black holes and dilaton charge in string theory
Goulart, Prieslei
2016-01-01
We give the most general four-dimensional non-extremal dyonic black solution for Einstein-Maxwell-dilaton theory in absence of a scalar potential. The solution is written in terms of five independent parameters: the electic charge $Q$, the magnetic charge $P$, the value of the dilaton at infinity $\\phi_{0}$, and two integration constants, $r_{1}$ and $r_{2}$. The dilaton charge is given in terms of all of these parameters. Particular choices of the integration constants allow us to recover the other known black hole solutions found before. We discuss the thermodynamical properties of these black holes for the non-extremal and extremal cases. From the solution for the dilaton it is straightforward to provide an answer to why is $\\phi_{H, \\text{extreme}}$ independent of $\\phi_{0}$ and to why $\\phi_{H, \\text{extreme}}=\\phi_{0}$ when the dilaton charge is zero.
Rotating and accelerating black holes with cosmological constant
Chen, Yu; Teo, Edward
2016-01-01
We propose a new form of the rotating C-metric with cosmological constant, which generalises the form found by Hong and Teo for the Ricci-flat case. This solution describes the entire class of spherical black holes undergoing rotation and acceleration in dS or AdS space-time. The new form allows us to identify the complete ranges of coordinates and parameters of this solution. We perform a systematic study of its geometrical and physical properties, and of the various limiting cases that arise from it.
Influence of frame-dragging on magnetic null points near rotating black holes
Karas, V.; Kopáček, O.; Kunneriath, D.
2012-02-01
Understanding the mechanisms of particle acceleration from the vicinity of black holes poses a challenge. Electromagnetic effects are thought to be a prime suspect, but details still need an explanation. To this end, we study a three-dimensional structure of oblique magnetic fields near a rotating black hole in vacuum. It has been proposed that such a setup can lead to efficient acceleration when plasma is injected near a magnetic null point. We focus our attention especially on the magnetic field in the immediate neighborhood of the magnetic null point, which was previously shown to occur in the equatorial plane. By employing the line integral convolution method, we visualize the magnetic field lines and explore the electric lines rising out of the equatorial plane. We show the magnetic field structure near the boundary of ergosphere, depending on the spin of the black hole. Electric field develops a non-vanishing component passing through the magnetic null point and ensuring efficient acceleration of charged particles from this particular location near the horizon. We also examine the effect of translatory boost on the field lines. Similarly to the frame-dragging by rotation, the linear motion carries field lines along with the black hole. The position of the magnetic null point recedes from the black hole horizon as the spin parameter increases. For the extreme value of a = 1, the null point can occur outside the ergosphere.
Dirac quasinormal modes of two-dimensional charged dilatonic black holes
Energy Technology Data Exchange (ETDEWEB)
Becar, Ramon [Universidad Catolica de Temuco, Departamento de Ciencias Matematicas y Fisicas, Temuco (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)
2014-06-15
We study charged fermionic perturbations in the background of two-dimensional charged dilatonic black holes, and we present the exact Dirac quasinormal modes. Also, we study the stability of these black holes under charged fermionic perturbations. (orig.)
Thermodynamics of charged Lovelock: AdS black holes
Energy Technology Data Exchange (ETDEWEB)
Prasobh, C.B.; Suresh, Jishnu; Kuriakose, V.C. [Cochin University of Science and Technology, Department of Physics, Cochin (India)
2016-04-15
We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second-order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime. (orig.)
Thermodynamics of charged Lovelock: AdS black holes
Prasobh, C. B.; Suresh, Jishnu; Kuriakose, V. C.
2016-04-01
We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second-order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime.
Oscillating supertubes and neutral rotating black hole microstates
Mathur, Samir D
2014-01-01
The construction of neutral black hole microstates is an important problem, with implications for the information paradox. In this paper we conjecture a construction of non-supersymmetric supergravity solutions describing D-brane configurations which carry mass and angular momentum, but no other conserved charges. We first study a classical string solution which locally carries dipole winding and momentum charges in two compact directions, but globally carries no net winding or momentum charge. We investigate its backreaction in the D1-D5 duality frame, where this object becomes a supertube which locally carries oscillating dipole D1-D5 and NS1-NS5 charges, and again carries no net charge. In the limit of an infinite straight supertube, we find an exact supergravity solution describing this object. We conjecture that a similar construction may be carried out based on a class of two-charge non-supersymmetric D1-D5 solutions. These results are a step towards demonstrating how neutral black hole microstates may ...
Oscillating supertubes and neutral rotating black hole microstates
Energy Technology Data Exchange (ETDEWEB)
Mathur, Samir D.; Turton, David [Department of Physics, The Ohio State University,191 W Woodruff Ave, Columbus, OH 43210 (United States)
2014-04-10
The construction of neutral black hole microstates is an important problem, with implications for the information paradox. In this paper we conjecture a construction of non-supersymmetric supergravity solutions describing D-brane configurations which carry mass and angular momentum, but no other conserved charges. We first study a classical string solution which locally carries dipole winding and momentum charges in two compact directions, but globally carries no net winding or momentum charge. We investigate its backreaction in the D1-D5 duality frame, where this object becomes a supertube which locally carries oscillating dipole D1-D5 and NS1-NS5 charges, and again carries no net charge. In the limit of an infinite straight supertube, we find an exact supergravity solution describing this object. We conjecture that a similar construction may be carried out based on a class of two-charge non-supersymmetric D1-D5 solutions. These results are a step towards demonstrating how neutral black hole microstates may be constructed in string theory.
Thermodynamics of Rotating Black Holes and Black Rings: Phase Transitions and Thermodynamic Volume
Directory of Open Access Journals (Sweden)
Natacha Altamirano
2014-03-01
Full Text Available In this review we summarize, expand, and set in context recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. We specifically consider the thermodynamics of higher-dimensional rotating asymptotically flat and AdS black holes and black rings in a canonical (fixed angular momentum ensemble. We plot the associated thermodynamic potential—the Gibbs free energy—and study its behavior to uncover possible thermodynamic phase transitions in these black hole spacetimes. We show that the multiply-rotating Kerr-AdS black holes exhibit a rich set of interesting thermodynamic phenomena analogous to the “every day thermodynamics” of simple substances, such as reentrant phase transitions of multicomponent liquids, multiple first-order solid/liquid/gas phase transitions, and liquid/gas phase transitions of the van derWaals type. Furthermore, the reentrant phase transitions also occur for multiply-spinning asymptotically flat Myers–Perry black holes. These phenomena do not require a variable cosmological constant, though they are more naturally understood in the context of the extended phase space. The thermodynamic volume, a quantity conjugate to the thermodynamic pressure, is studied for AdS black rings and demonstrated to satisfy the reverse isoperimetric inequality; this provides a first example of calculation confirming the validity of isoperimetric inequality conjecture for a black hole with non-spherical horizon topology. The equation of state P = P(V,T is studied for various black holes both numerically and analytically—in the ultraspinning and slow rotation regimes.
Rotating (A)dS black holes in bigravity
Ayón-Beato, Eloy; Méndez-Zavaleta, Julio A
2015-01-01
In this paper we explore the advantage of using the Kerr-Schild ansatz in the search of analytic configurations to bigravity. It turns out that it plays a crucial role by providing means to straightforwardly calculate the square root matrix encoding the interaction terms between both gravities. We rederive in this spirit the Babichev-Fabbri family of asymptotically flat rotating black holes with the aid of an emerging circularity theorem. Taking into account that the interaction terms contain by default two cosmological constants, we repeat our approach starting from the more natural seeds for the Kerr-Schild ansatz in this context: the (A)dS spacetimes. As result, we show that a couple of Kerr-(A)dS black holes constitute an exact solution to ghost free bigravity. These black holes share the same angular momentum and (A)dS radius but their masses are not constrained to be equal, similarly to the asymptotically flat case.
Mass loss from advective accretion disc around rotating black holes
Aktar, Ramiz; Nandi, Anuj
2015-01-01
We examine the properties of the outflowing matter from an advective accretion disc around a spinning black hole. During accretion, rotating matter experiences centrifugal pressure supported shock transition that effectively produces a virtual barrier around the black hole in the form of post-shock corona (hereafter, PSC). Due to shock compression, PSC becomes hot and dense that eventually deflects a part of the inflowing matter as bipolar outflows because of the presence of extra thermal gradient force. In our approach, we study the outflow properties in terms of the inflow parameters, namely specific energy (${\\mathcal E}$) and specific angular momentum ($\\lambda$) considering the realistic outflow geometry around the rotating black holes. We find that spin of the black hole ($a_k$) plays an important role in deciding the outflow rate $R_{\\dot m}$ (ratio of mass flux of outflow and inflow), in particular, $R_{\\dot m}$ is directly correlated with $a_k$ for the same set of inflow parameters. It is found that ...
Integrability in conformally coupled gravity: Taub-NUT spacetimes and rotating black holes
Bardoux, Yannis; Caldarelli, Marco M.; Charmousis, Christos
2014-05-01
We consider four dimensional stationary and axially symmetric spacetimes for conformally coupled scalar-tensor theories. We show that, in analogy to the Lewis-Papapetrou problem in General Relativity (GR), the theory at hand can be recast in an analogous integrable form. We give the relevant rod formalism, introduced by Weyl for vacuum GR, explicitly giving the rod structure of the black hole of Bocharova et al. and Bekenstein (BBMB), in complete analogy to the Schwarzschild solution. The additional scalar field is shown to play the role of an extra Weyl potential. We then employ the Ernst method as a concrete solution generating example to obtain the Taub-NUT version of the BBMB hairy black hole. The solution is easily extended to include a cosmological constant. We show that the anti-de Sitter hyperbolic version of this solution is free of closed timelike curves that plague usual Taub-NUT metrics, and thus consists of a rotating, asymptotically locally anti-de Sitter black hole. This stationary solution has no curvature singularities whatsoever in the conformal frame, and the NUT charge is shown here to regularize the central curvature singularity of the corresponding static black hole. Given our findings we discuss the anti-de Sitter hyperbolic version of Taub-NUT in four dimensions, and show that the curvature singularity of the NUT-less solution is now replaced by a neighbouring chronological singularity screened by horizons. We argue that the properties of this rotating black hole are very similar to those of the rotating BTZ black hole in three dimensions.
Integrability in conformally coupled gravity: Taub-NUT spacetimes and rotating black holes
Energy Technology Data Exchange (ETDEWEB)
Bardoux, Yannis [Laboratoire de Physique Théorique (LPT), Université Paris-Sud, CNRS UMR 8627, F-91405 Orsay (France); Caldarelli, Marco M. [Mathematical Sciences and STAG research centre, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Charmousis, Christos [Laboratoire de Physique Théorique (LPT), Université Paris-Sud, CNRS UMR 8627, F-91405 Orsay (France); Laboratoire de Mathématiques et Physique Théorique (LMPT), Université Tours, UFR Sciences et Techniques, Parc de Grandmont, F-37200 Tours (France)
2014-05-09
We consider four dimensional stationary and axially symmetric spacetimes for conformally coupled scalar-tensor theories. We show that, in analogy to the Lewis-Papapetrou problem in General Relativity (GR), the theory at hand can be recast in an analogous integrable form. We give the relevant rod formalism, introduced by Weyl for vacuum GR, explicitly giving the rod structure of the black hole of Bocharova et al. and Bekenstein (BBMB), in complete analogy to the Schwarzschild solution. The additional scalar field is shown to play the role of an extra Weyl potential. We then employ the Ernst method as a concrete solution generating example to obtain the Taub-NUT version of the BBMB hairy black hole. The solution is easily extended to include a cosmological constant. We show that the anti-de Sitter hyperbolic version of this solution is free of closed timelike curves that plague usual Taub-NUT metrics, and thus consists of a rotating, asymptotically locally anti-de Sitter black hole. This stationary solution has no curvature singularities whatsoever in the conformal frame, and the NUT charge is shown here to regularize the central curvature singularity of the corresponding static black hole. Given our findings we discuss the anti-de Sitter hyperbolic version of Taub-NUT in four dimensions, and show that the curvature singularity of the NUT-less solution is now replaced by a neighbouring chronological singularity screened by horizons. We argue that the properties of this rotating black hole are very similar to those of the rotating BTZ black hole in three dimensions.
Evolution Of Binary Supermassive Black Holes In Rotating Nuclei
Rasskazov, Alexander
2016-01-01
Interaction of a binary supermassive black hole with stars in a galactic nucleus can result in changes to all the elements of the binary's orbit, including the angles that define its orientation. If the nucleus is rotating, the orientation changes can be large, causing large changes in the binary's orbital eccentricity as well. We present a general treatment of this problem based on the Fokker-Planck equation for f, defined as the probability distribution for the binary's orbital elements. First- and second-order diffusion coefficients are derived for the orbital elements of the binary using numerical scattering experiments, and analytic approximations are presented for some of these coefficients. Solutions of the Fokker-Planck equation are then derived under various assumptions about the initial rotational state of the nucleus and the binary hardening rate. We find that the evolution of the orbital elements can become qualitatively different when we introduce nuclear rotation: 1) the orientation of the binar...
Analytic treatment of the system of a Kerr-Newman black hole and a charged massive scalar field
Hod, Shahar
2016-08-01
Charged rotating Kerr-Newman black holes are known to be superradiantly unstable to perturbations of charged massive bosonic fields whose proper frequencies lie in the bounded regime 0 eikonal large-mass regime, the superradiant instability growth rates of the explosive scalar fields are characterized by a nontrivial (nonmonotonic) dependence on the dimensionless charge-to-mass ratio q /μ . In particular, for given parameters {M ,Q ,J } of the central Kerr-Newman black hole, we determine analytically the optimal charge-to-mass ratio q /μ of the explosive scalar field which maximizes the growth rate of the superradiant instabilities in the composed Kerr-Newman-black-hole-charged-massive-scalar-field system.
Null Geodesics in a Magnetically Charged Stringy Black Hole Spacetime
Kuniyal, Ravi Shankar; Nandan, Hemwati; Purohit, K D
2015-01-01
We study the geodesic motion of massless test particles in the background of a magnetic charged black hole spacetime in four dimensions in dilaton-Maxwell gravity. The behaviour of effective potential in view of the different values of black hole parameters is analysed in the equatorial plane. The possible orbits for null geodesics are also discussed in detail in view of the different values of the impact parameter. We have also calculated the frequency shift of photons in this spacetime. The results obtained are then compared with those for the electrically charged stringy black hole spacetime and the Schwarzschild black hole spacetime. It is observed that there exists no stable circular orbit outside the event horizon for massless test particles.
Charged dilatonic black holes in gravity's rainbow
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Faizal, Mir [University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Panah, B.E. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Panahiyan, S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of)
2016-05-15
In this paper, we present charged dilatonic black holes in gravity's rainbow. We study the geometric and thermodynamic properties of black hole solutions. We also investigate the effects of rainbow functions on different thermodynamic quantities for these charged black holes in dilatonic gravity's rainbow. Then we demonstrate that the first law of thermodynamics is valid for these solutions. After that, we investigate thermal stability of the solutions using the canonical ensemble and analyze the effects of different rainbow functions on the thermal stability. In addition, we present some arguments regarding the bound and phase transition points in context of geometrical thermodynamics. We also study the phase transition in extended phase space in which the cosmological constant is treated as the thermodynamic pressure. Finally, we use another approach to calculate and demonstrate that the obtained critical points in extended phase space represent a second order phase transition for these black holes. (orig.)
Superrotation Charge and Supertranslation Hair on Black Holes
Hawking, Stephen W; Strominger, Andrew
2016-01-01
It is shown that black hole spacetimes in classical Einstein gravity are characterized by, in addition to their ADM mass M , momentum P ~ , angular momentum J ~ and boost charge K, an infinite head of supertranslation hair. The distinct black holes are distinguished by classical superrotation charges measured at infinity. Solutions with supertranslation hair are diffeomorphic to the Schwarzschild spacetime, but the diffeomorphisms are part of the BMS subgroup and act nontrivially on the physical phase space. It is shown that a black hole can be supertranslated by throwing in an asymmetric shock wave. A leading-order Bondi-gauge expression is derived for the linearized horizon supertranslation charge and shown to generate, via the Dirac bracket, supertranslations on the linearized phase space of gravitational excitations of the horizon. The considerations of this paper are largely classical augmented by comments on their implications for the quantum theory.
Entropy Corrections for a Charged Black Hole of String Theory*
Institute of Scientific and Technical Information of China (English)
Alexis Larra(n)aga
2011-01-01
We study the entropy of the Gibbons-Macda-Garfinkle-Horowitz-Strominger (GMGHS) charged black hole, originated from the effective action that emerges in the low-energy of string theory, beyond semiclassical approximations. Applying the properties of exact differentials for three variables to the first law thermodynamics ve derive the quantum corrections to the entropy of the black hole. The leading (logarithmic) and non leading corrections to the area law are obtained.
D0-brane description of the charged black hole
Kato, Y; Sugamoto, A; Kato, Yuriko; Nojiri, Shin'ichi; Sugamoto, Akio
1998-01-01
The charged black hole is considered from the viewpoint of D0-brane in the Matrix theory. It can be obtained from the Kaluza-Klein mechanism by boosting the Schwarzschild black hole in a circle, which is the compactified one dimensional space. Especially, how the extremal limit is realized by the Boltzmann gas of D0-brane, has been shown. In the course of our discussion, the Virial theorem for the statistical average plays an important role.
Quasinormal modes of semiclassical electrically charged black holes
Energy Technology Data Exchange (ETDEWEB)
Fernandez Piedra, Owen Pavel [Departamento de Fisica y Quimica, Facultad de Mecanica, Universidad de Cienfuegos, Carretera a Rodas, km 4, Cuatro Caminos, Cienfuegos (Cuba); De Oliveira, Jeferson, E-mail: opavel@ucf.edu.cu, E-mail: jeferson@fma.if.usp.br [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970, Sao Paulo (Brazil)
2011-04-21
We report the results concerning the influence of vacuum polarization due to quantum massive vector, scalar and spinor fields on the scalar sector of quasinormal modes in spherically symmetric charged black holes. The vacuum polarization from quantized fields produces a shift in the values of the quasinormal frequencies, and correspondingly the semiclassical system becomes a better oscillator with respect to the classical Reissner-Nordstroem black hole.
Collision of two general particles around a rotating regular Hayward's black holes
Energy Technology Data Exchange (ETDEWEB)
Amir, Muhammed; Ahmed, Fazlay [Center for Theoretical Physics, Jamia Millia Islamia, New Delhi (India); Ghosh, Sushant G. [Center for Theoretical Physics, Jamia Millia Islamia, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag X54001, Durban (South Africa)
2016-10-15
The rotating regular Hayward's spacetime, apart from mass (M) and angular momentum (a), has an additional deviation parameter (g) due to the magnetic charge, which generalizes the Kerr black hole when g ≠ 0; for g = 0 it goes over to the Kerr black hole. We analyze how the ergoregion is affected by the parameter g to show that the area of the ergoregion increases with increasing values of g. Further, for each g, there exists a critical a{sub E}, which corresponds to a regular extremal black hole with degenerate horizons r = r{sup E}{sub H}. a{sub E} decreases whereas r{sup E}{sub H} increases with an increase in the parameter g. Banados, Silk, and West (BSW) demonstrated that the extremal Kerr black hole can act as a particle accelerator with arbitrarily high center-of-mass energy (E{sub CM}) when the collision of two particles takes place near the horizon. We study the BSW process for two particles with different rest masses, m{sub 1} and m{sub 2}, moving in the equatorial plane of the extremal Hayward's black hole for different values of g, to show that E{sub CM} is arbitrarily high when one of the particles takes a critical value of the angular momentum. Our result, in the limit g → 0, reduces to that of the Kerr black hole. (orig.)
Rotating black holes in 4d gauged supergravity
Energy Technology Data Exchange (ETDEWEB)
Gnecchi, Alessandra [Institute for Theoretical Physics and Spinoza Institute, Utrecht University,3508 TD Utrecht (Netherlands); Hristov, Kiril [Dipartimento di Fisica, Università di Milano-Bicocca, and INFN, sezione di Milano-Bicocca,Piazza della Scienza 3, 20126 Milano (Italy); Klemm, Dietmar [Dipartimento di Fisica, Università di Milano, and INFN, sezione di Milano,Via Celoria 16, 20133 Milano (Italy); Toldo, Chiara [Institute for Theoretical Physics and Spinoza Institute, Utrecht University,3508 TD Utrecht (Netherlands); Vaughan, Owen [Department of Mathematics and Center for Mathematical Physics, University of Hamburg,Bundesstrasse 55, 20146 Hamburg (Germany)
2014-01-23
We present new results towards the construction of the most general black hole solutions in four-dimensional Fayet-Iliopoulos gauged supergravities. In these theories black holes can be asymptotically AdS and have arbitrary mass, angular momentum, electric and magnetic charges and NUT charge. Furthermore, a wide range of horizon topologies is allowed (compact and noncompact) and the complex scalar fields have a nontrivial radial and angular profile. We construct a large class of solutions in the simplest single scalar model with prepotential F=−iX{sup 0}X{sup 1} and discuss their thermodynamics. Moreover, various approaches and calculational tools for facing this problem with more general prepotentials are presented.
Electromagnetic Luminosity of the Coalescence of Charged Black Hole Binaries
Liebling, Steven L
2016-01-01
The observation of a possible electromagnetic counterpart by the Fermi GBM group to the aLIGO detection of the merger of a black hole binary has spawned a number of ideas about its source. Furthermore, observations of fast radio bursts (FRBs) have similarly resulted in a range of new models that might endow black hole binaries with electromagnetic signatures. In this context, even the unlikely idea that astrophysical black holes may have significant charge is worth exploring, and here we present results from the simulation of weakly charged black holes as they orbit and merge. Our simulations suggest that a black hole binary with mass comparable to that observed in GW150914 could produce the level of electromagnetic luminosity observed by Fermi GBM ($10^{49}$ ergs/s) with a non-dimensional charge of $q \\equiv Q/M = 10^{-4}$ assuming good radiative efficiency. However even a charge such as this is difficult to imagine avoiding neutralization long enough for the binary to produce its electromagnetic counterpart...
Gyromagnetic factor of rotating disks of electrically charged dust in general relativity
Liu Pynn, Yu-Chun; Macedo, Rodrigo Panosso; Breithaupt, Martin; Palenta, Stefan; Meinel, Reinhard
2016-11-01
We calculated the dimensionless gyromagnetic ratio ("g -factor") of self-gravitating, uniformly rotating disks of dust with a constant specific charge ɛ . These disk solutions to the Einstein-Maxwell equations depend on ɛ and a "relativity parameter" γ (0 <γ ≤1 ) up to a scaling parameter. Accordingly, the g -factor is a function g =g (γ ,ɛ ). The Newtonian limit is characterized by γ ≪1 , whereas γ →1 leads to a black-hole limit. The g -factor, for all ɛ , approaches the values g =1 as γ →0 and g =2 as γ →1 .
Gyromagnetic factor of rotating disks of electrically charged dust in general relativity
Pynn, Yu-Chun; Breithaupt, Martin; Palenta, Stefan; Meinel, Reinhard
2016-01-01
We calculated the dimensionless gyromagnetic ratio ("$g$-factor") of self-gravitating, uniformly rotating disks of dust with a constant specific charge $\\epsilon$. These disk solutions to the Einstein-Maxwell equations depend on $\\epsilon$ and a "relativity parameter" $\\gamma$ ($0<\\gamma\\le 1$) up to a scaling parameter. Accordingly, the $g$-factor is a function $g=g(\\gamma,\\epsilon)$. The Newtonian limit is characterized by $\\gamma \\ll 1$, whereas $\\gamma\\to 1$ leads to a black-hole limit. The $g$-factor, for all $\\epsilon$, approaches the values $g=1$ as $\\gamma\\to 0$ and $g=2$ as $\\gamma\\to 1$.
Vacum Black Hole Mass Formula Is a Vanishing Noether Charge
Institute of Scientific and Technical Information of China (English)
WUXiao－Ning; HUANGChao－Guang; 等
2002-01-01
The Noether current and its variation relation with respect to diffeomorphism invariance of gravitational theories have been derived from the horizontal variation and vertical-horizontal bi-variation of the Lagrangian,respectively.For Einstein's GR in the stationary,axisymmetric black holes,the mass formula in vacuum can be derived from this Noether current although it definitely vanishes.This indicates that the mass formula of black holes is a vanishing Noether charge in this case.The first law of black hole thermodynamics can also be derived from the variation relation of this vanishing Noether current.
Timelike geodesics around a charged spherically symmetric dilaton black hole
Directory of Open Access Journals (Sweden)
Blaga C.
2015-01-01
Full Text Available In this paper we study the timelike geodesics around a spherically symmetric charged dilaton black hole. The trajectories around the black hole are classified using the effective potential of a free test particle. This qualitative approach enables us to determine the type of orbit described by test particle without solving the equations of motion, if the parameters of the black hole and the particle are known. The connections between these parameters and the type of orbit described by the particle are obtained. To visualize the orbits we solve numerically the equation of motion for different values of parameters envolved in our analysis. The effective potential of a free test particle looks different for a non-extremal and an extremal black hole, therefore we have examined separately these two types of black holes.
Black hole entropy and Lorentz-diffeomorphism Noether charge
Jacobson, Ted; Mohd, Arif
2015-01-01
We show that, in the first or second order orthonormal frame formalism, black hole entropy is the horizon Noether charge for a combination of diffeomorphism and local Lorentz symmetry involving the Lie derivative of the frame. The Noether charge for diffeomorphisms alone is unsuitable, since a regular frame cannot be invariant under the flow of the Killing field at the bifurcation surface. We apply this formalism to Lagrangians polynomial in wedge products of the frame field 1-form and curvat...
Geometric aspects of charged black holes in Palatini theories
Olmo, Gonzalo J; Sanchez-Puente, A
2015-01-01
Charged black holes in gravity theories in the Palatini formalism present a number of unique properties. Their innermost structure is topologically nontrivial, representing a wormhole supported by a sourceless electric flux. For certain values of their effective mass and charge curvature divergences may be absent, and their event horizon may also disappear yielding a remnant. We give an overview of the mathematical derivation of these solutions and discuss their geodesic structure and other geometric properties.
Extracting black-hole's rotational energy: the generalized Penrose process
Lasota, J -P; Abramowicz, M; Tchekhovskoy, A; Narayan, R
2014-01-01
In the case involving particles the necessary and sufficient condition for the Penrose process to extract energy from a rotating black hole is absorption of particles with negative energies and angular momenta. No torque at the black hole horizon occurs. In this article we consider the case of arbitrary fields or matter described by an unspecified, general energy-momentum tensor and show that the necessary and sufficient condition for extraction of black-hole's rotational energy is analogous to that in mechanical Penrose process: absorption of negative energy and negative angular momentum. We also show that a necessary condition for the Penrose process to occur is for the Noether current (the conserved energy-momentum density vector) to be spacelike or past-directed (timelike or null) on some part of the horizon. In the particle case our general criterion for the occurrence of a Penrose process reproduces the standard result. In the case of relativistic jet-producing "magnetically arrested disks" we show that...
Explosion and final state of the charged black hole bomb
Sanchis-Gual, Nicolas; Montero, Pedro J; Font, José A; Herdeiro, Carlos
2015-01-01
A Reissner-Nordstr\\"om black hole (BH) is superradiantly unstable against spherical perturbations of a charged scalar field, enclosed in a cavity, with frequency lower than a critical value. We use numerical relativity techniques to follow the development of this unstable system -- dubbed charged BH bomb -- into the non-linear regime, solving the full Einstein--Maxwell--Klein-Gordon equations, in spherical symmetry. We show that: $i)$ the process stops before all the charge is extracted from the BH; $ii)$ the system settles down into a hairy BH: a charged horizon in equilibrium with a scalar field condensate, whose phase is oscillating at the (final) critical frequency. For low scalar field charge, $q$, the final state is approached smoothly and monotonically. For large $q$, however, the energy extraction overshoots and an explosive phenomenon, akin to a $bosenova$, pushes some energy back into the BH. The charge extraction, by contrast, does not reverse.
Quasinormal modes of maximally charged black holes
Onozawa, H; Okamura, T; Ishihara, H; Onozawa, Hisashi; Mishima, Takashi; Okamura, Takashi; Ishihara, Hideki
1996-01-01
A new algorithm for computing the accurate values of quasinormal frequencies of extremal Reissner-Nordstr\\"{o}m black holes is presented. The numerically computed values are consistent with the values earlier obtained by Leaver and those obtained through the WKB method. Our results are more precise than other results known to date. We also find a curious fact that the resonant frequencies of gravitational waves with multi-pole index l coincide with those of electromagnetic waves with multi-pole index l-1 in the extremal limit.
Thermodynamics of charged black holes with a nonlinear electrodynamics source
Gonzalez, Hernan A; Martinez, Cristian
2009-01-01
We study the thermodynamical properties of electrically charged black hole solutions of a nonlinear electrodynamics theory defined by a power p of the Maxwell invariant, which is coupled to Einstein gravity in four and higher spacetime dimensions. Depending on the range of the parameter p, these solutions present different asymptotic behaviors. We compute the Euclidean action with the appropriate boundary term in the grand canonical ensemble. The thermodynamical quantities are identified and in particular, the mass and the charge are shown to be finite for all classes of solutions. Interestingly, a generalized Smarr formula is derived and it is shown that this latter encodes perfectly the different asymptotic behaviors of the black hole solutions. The local stability is analyzed by computing the heat capacity and the electrical permittivity and we find that a set of small black holes are locally stable. In contrast to the standard Reissner-Nordstrom solution, there is a first-order phase transition between a ...
Quasars a supermassive rotating toroidal black hole interpretation
Spivey, R J
2000-01-01
A supermassive rotating toroidal black hole (TBH) is proposed as the fundamental structure of quasars and other jet-producing active galactic nuclei. Rotating protogalaxies gather matter from the central gaseous region leading to the birth of massive toroidal stars whose internal nuclear reactions proceed very rapidly. Once the nuclear fuel is spent, gravitational collapse produces a slender ring-shaped TBH remnant. These events are typically the first supernovae of the host galaxies. Given time the TBH mass increases through continued accretion by several orders of magnitude, the event horizon swells whilst the central aperture shrinks. The difference in angular velocities between the accreting matter and the TBH induces a magnetic field that is strongest in the region of the central aperture and innermost ergoregion. Due to the presence of negative energy states when such a gravitational vortex is immersed in an electromagnetic field, circumstances are near ideal for energy extraction via non-thermal radiat...
Gußmann, Alexander
2017-03-01
The existence of the classical black hole solutions of the Einstein–Yang–Mills–Higgs equations with non-Abelian Yang–Mills–Higgs hair implies that not all classical stationary magnetically charged black holes can be uniquely described by their asymptotic characteristics. In fact, in a certain domain of parameters, there exist different spherically-symmetric, non-rotating and asymptotically-flat classical black hole solutions of the Einstein–Yang–Mills–Higgs equations which have the same ADM mass and the same magnetic charge but significantly different geometries in the near-horizon regions. (These are black hole solutions which are described by a Reissner–Nordström metric on the one hand and the black hole solutions with non-Abelian Yang–Mills–Higgs hair which are described by a metric which is not of Reissner–Nordström form on the other hand). One can experimentally distinguish such black holes with the same asymptotic characteristics but different near-horizon geometries classically by probing the near-horizon regions of the black holes. We argue that one way to probe the near-horizon region of a black hole which allows one to distinguish magnetically charged black holes with the same asymptotic characteristics but different near-horizon geometries is by classical scattering of waves. Using the example of a minimally-coupled massless probe scalar field scattered by magnetically charged black holes which can be obtained as solutions of the Einstein–Yang–Mills–Higgs equations with a Higgs triplet and gauge group SU(2) in the limit of an infinite Higgs self-coupling constant we show how, in this case, the scattering cross sections differ for the magnetically charged black holes with different near-horizon geometries but the same asymptotic characteristics. We find in particular that the characteristic glory peaks in the cross sections are located at different scattering angles.
Spinning Particle as a Non-trivial Rotating Super Black Hole with Broken N=2 Supersymmetry
Burinskii, A
1999-01-01
A non-trivial super black hole solution is considered as representing a combined model of the Kerr spinning particle and superparticle. Treatment is based on the broken N=2 supersymmetry in supergravity in analogue with Deser-Zumino model of broken supersymmetry in N=1 supergravity. There appears a non-linear realization of broken supersymmetry, which is very specific for the Kerr geometry and which leads to a family of the exact non-trivial rotating and charged super black hole solutions (super-Kerr-Newman solutions). Peculiarities of the super-Kerr-Newman solutions and in particular the appearance of the short ranging traveling waves of torsion and other fields, build of the nilpotent Grassmann variables, on the pure bosonic Kerr-Newman background are discussed.
Scalar perturbations of higher dimensional rotating and ultra-spinning black holes
Cardoso, V; Yoshida, S; Cardoso, Vitor; Siopsis, George; Yoshida, Shijun
2005-01-01
We investigate the stability of higher dimensional rotating black holes against scalar perturbations. In particular, we make a thorough numerical and analytical analysis of six-dimensional black holes, not only in the low rotation regime but in the high rotation regime as well. Our results suggest that higher dimensional Kerr black holes are stable against scalar perturbations, even in the ultra-spinning regime.
Energy Technology Data Exchange (ETDEWEB)
Becar, Ramon [Universidad Catolica de Temuco, Departamento de Ciencias Matematicas y Fisicas, Temuco (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Valparaiso (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)
2015-02-01
We study massive charged fermionic perturbations in the background of a charged two-dimensional dilatonic black hole, and we solve the Dirac equation analytically. Then we compute the reflection and transmission coefficients and the absorption cross section for massive charged fermionic fields, and we show that the absorption cross section vanishes at the low- and high-frequency limits. However, there is a range of frequencies where the absorption cross section is not null. Furthermore, we study the effect of the mass and electric charge of the fermionic field over the absorption cross section. (orig.)
Photonic Bell states creation around rotating black holes
Racorean, Ovidiu
2016-01-01
We argue that spinning black holes are capable to implement complex quantum information processes encoded in X-ray photons emitted by the accretion disk. Recently, numerical simulations showed that X-ray photons emitted by accretion disk acquire rotation of polarization angle and orbital angular momentum due to strong gravitational field in the vicinity of the rotating black holes. Based on these two degrees of freedom we construct a bipartite two-level quantum system of the photons emitted by the accretion disk. To characterize the quantum states of this system we consider linear entropy for the reduced density matrix of polarization with the intention to exploit its direct relation with the photons degree of polarization. Since the X-ray radiation has a minimum degree of polarization located at the transition region of the accretion disk, the linear entropy is higher for the photons emitted on this region inferring a higher degree of entanglement for the composite system. We emphasize that for an extreme ro...
Scalar clouds in charged stringy black hole-mirror system
Li, Ran; Zhao, Junkun; Wu, Xinghua; Zhang, Yanming
2015-04-01
It was reported that massive scalar fields can form bound states around Kerr black holes (Herdeiro and Radu, Phys. Rev. Lett. 112:221101, 2014). These bound states are called scalar clouds; they have a real frequency , where is the azimuthal index and is the horizon angular velocity of Kerr black hole. In this paper, we study scalar clouds in a spherically symmetric background, i.e. charged stringy black holes, with the mirror-like boundary condition. These bound states satisfy the superradiant critical frequency condition for a charged scalar field, where is the charge of the scalar field, and is the horizon's electrostatic potential. We show that, for the specific set of black hole and scalar field parameters, the clouds are only possible for specific mirror locations . It is shown that analytical results of the mirror location for the clouds perfectly coincide with numerical results in the regime. We also show that the scalar clouds are also possible when the mirror locations are close to the horizon. Finally, we provide an analytical calculation of the specific mirror locations for the scalar clouds in the regime.
Scalar clouds in charged stringy black hole-mirror system
Li, Ran; Wu, Xinghua; Zhang, Yanming
2015-01-01
It is reported that massive scalar fields can form bound states around Kerr black holes [C. Herdeiro, and E. Radu, Phys. Rev. Lett. 112, 221101 (2014)]. These bound states are called scalar clouds, which have a real frequency $\\omega=m\\Omega_H$, where $m$ is the azimuthal index and $\\Omega_H$ is the horizon angular velocity of Kerr black hole. In this paper, we study scalar clouds in a spherically symmetric background, i.e. charged stringy black holes, with the mirror-like boundary condition. These bound states satisfy the superradiant critical frequency condition $\\omega=q\\Phi_H$ for the charged scalar field, where $q$ is the charge of scalar field, and $\\Phi_H$ is the horizon electrostatic potential. We show that, for the specific set of black hole and scalar field parameters, the clouds are only possible for the specific mirror locations $r_m$. It is shown that the analytical results of mirror location $r_m$ for the clouds are perfectly coincide with the numerical results. In addition, we show that the sca...
Scalar clouds in charged stringy black hole-mirror system
Energy Technology Data Exchange (ETDEWEB)
Li, Ran; Zhao, Junkun; Wu, Xinghua; Zhang, Yanming [Henan Normal University, Department of Physics, Xinxiang (China)
2015-04-15
It was reported that massive scalar fields can form bound states around Kerr black holes (Herdeiro and Radu, Phys. Rev. Lett. 112:221101, 2014). These bound states are called scalar clouds; they have a real frequency ω = mΩ{sub H}, where m is the azimuthal index and Ω{sub H} is the horizon angular velocity of Kerr black hole. In this paper, we study scalar clouds in a spherically symmetric background, i.e. charged stringy black holes, with the mirror-like boundary condition. These bound states satisfy the superradiant critical frequency condition ω = qΦ{sub H} for a charged scalar field, where q is the charge of the scalar field, and Φ{sub H} is the horizon's electrostatic potential. We show that, for the specific set of black hole and scalar field parameters, the clouds are only possible for specific mirror locations r{sub m}. It is shown that analytical results of the mirror location r{sub m} for the clouds perfectly coincide with numerical results in the qQ << 1 regime. We also show that the scalar clouds are also possible when the mirror locations are close to the horizon. Finally, we provide an analytical calculation of the specific mirror locations rm for the scalar clouds in the qQ >> 1 regime. (orig.)
Thermodynamics of charged black holes with a nonlinear electrodynamics source
González, Hernán A.; Hassaïne, Mokhtar; Martínez, Cristián
2009-11-01
We study the thermodynamical properties of electrically charged black hole solutions of a nonlinear electrodynamics theory defined by a power p of the Maxwell invariant, which is coupled to Einstein gravity in four and higher spacetime dimensions. Depending on the range of the parameter p, these solutions present different asymptotic behaviors. We compute the Euclidean action with the appropriate boundary term in the grand canonical ensemble. The thermodynamical quantities are identified and, in particular, the mass and the charge are shown to be finite for all classes of solutions. Interestingly, a generalized Smarr formula is derived and it is shown that this latter encodes perfectly the different asymptotic behaviors of the black hole solutions. The local stability is analyzed by computing the heat capacity and the electrical permittivity and we find that a set of small black holes is locally stable. In contrast to the standard Reissner-Nordström solution, there is a first-order phase transition between a class of these nonlinear charged black holes and the Minkowski spacetime.
Black hole free energy during charged collapse: a numerical study
Beauchesne, Hugues
2012-01-01
We perform a numerical investigation of the thermodynamics during the collapse of a charged (complex) scalar field to a Reissner-Nordstr\\"om (RN) black hole in isotropic coordinates. Numerical work on gravitational collapse in isotropic coordinates has recently shown that the negative of the total Lagrangian approaches the Helmholtz free energy F= E-TS of a Schwarzschild black hole at late times of the collapse (where E is the black hole mass, T the temperature and S the entropy). The relevant thermodynamic potential for the RN black hole is the Gibbs free energy G=E-TS-$\\Phi_H$ Q where Q is the charge and $\\Phi_H$ the electrostatic potential at the outer horizon. In charged collapse, there is a large outgoing matter wave which prevents the exterior from settling quickly to a static state. However, the interior region is not affected significantly by the wave. We find numerically that the interior contribution to the Gibbs free energy is entirely gravitational and accumulates in a thin shell just inside the h...
On the universality of thermodynamics and $\\eta/s$ ratio for the charged Lovelock black branes
Cadoni, Mariano; Frassino, Antonia; Tuveri, Matteo
2016-01-01
We investigate general features of charged Lovelock black branes by giving a detailed description of geometrical, thermodynamic and holographic properties of charged Gauss-Bonnet (GB) black branes in five dimensions. We show that when expressed in terms of effective physical parameters, the thermodynamic behaviour of charged GB black branes is completely indistinguishable from that of charged Einstein black branes. Moreover, the extremal, near-horizon limit of the two classes of branes is exa...
The causal structure of dynamical charged black holes
Energy Technology Data Exchange (ETDEWEB)
Hong, Sungwook E; Hwang, Dong-il; Stewart, Ewan D; Yeom, Dong-han, E-mail: eostm@muon.kaist.ac.k, E-mail: enotsae@gmail.co, E-mail: innocent@muon.kaist.ac.k [Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of)
2010-02-21
We study the causal structure of dynamical charged black holes, with a sufficient number of massless fields, using numerical simulations. Neglecting Hawking radiation, the inner horizon is a null Cauchy horizon and a curvature singularity due to mass inflation. When we include Hawking radiation, the inner horizon becomes space-like and is separated from the Cauchy horizon, which is parallel to the out-going null direction. Since a charged black hole must eventually transit to a neutral black hole, we studied the neutralization of the black hole and observed that the inner horizon evolves into a space-like singularity, generating a Cauchy horizon which is parallel to the in-going null direction. Since the mass function is finite around the inner horizon, the inner horizon is regular and penetrable in a general relativistic sense. However, since the curvature functions become trans-Planckian, we cannot say more about the region beyond the inner horizon, and it is natural to say that there is a 'physical' space-like singularity. However, if we assume an exponentially large number of massless scalar fields, our results can be extended beyond the inner horizon. In this case, strong cosmic censorship and black hole complementarity can be violated.
Thermodynamics of Rotating Black Branes in Gauss-Bonnet-Born-Infeld Gravity
Dehghani, M H
2006-01-01
Considering both the Gauss-Bonnet and the Born-Infeld terms, which are on similar footing with regard to string corrections on the gravity side and electrodynamic side, we present a new class of rotating solutions in Gauss-Bonnet gravity with $k$ rotation parameters in the presence of a nonlinear electromagnetic field. These solutions, which are asymptotically anti-de Sitter in the presence of cosmological constant, may be interpreted as black brane solutions with inner and outer event horizons, an extreme black brane or naked singularity provided the metric parameters are chosen suitably. We calculate the finite action and conserved quantities of the solutions by using the counterterm method, and find that these quantities do not depend on the Gauss-Bonnet parameter. We also compute the temperature, the angular velocities, the electric charge and the electric potential. Then, we calculate the entropy of the black brane through the use of Gibbs-Duhem relation and show that it obeys the area law of entropy. We...
Superradiant instabilities of rotating black holes in the time domain
Dolan, Sam R
2013-01-01
Bosonic fields on rotating black hole spacetimes are subject to amplification by superradiance, which induces exponentially-growing instabilities (the `black hole bomb') in two scenarios: if the black hole is enclosed by a mirror, or if the bosonic field has rest mass. Here we present a time-domain study of the scalar field on Kerr spacetime which probes ultra-long timescales up to $t \\lesssim 5 \\times 10^6 M$, to reveal the growth of the instability. We describe an highly-efficient method for evolving the field, based on a spectral decomposition into a coupled set of 1+1D equations, and an absorbing boundary condition inspired by the `perfectly-matched layers' paradigm. First, we examine the mirror case to study how the instability timescale and mode structure depend on mirror radius. Next, we examine the massive-field, whose rich spectrum (revealed through Fourier analysis) generates `beating' effects which disguise the instability. We show that the instability is clearly revealed by tracking the stress-ene...
Rotating black holes in an expanding universe from fake supergravity
Chimento, Samuele
2014-01-01
Using the recipe of arXiv:0902.4814, where all fake supersymmetric backgrounds of matter-coupled fake N=2, d=4 gauged supergravity were classified, we construct dynamical rotating black holes in an expanding FLRW universe. This is done for two different prepotentials that are both truncations of the stu model and correspond to just one vector multiplet. In this scenario, the cosmic expansion is driven by two U(1) gauge fields and by a complex scalar that rolls down its potential. Generically, the solutions of arXiv:0902.4814 are fibrations over a Gauduchon-Tod base space, and we make three different choices for this base, namely flat space, the three-sphere and the Berger sphere. In the first two cases, the black holes are determined by harmonic functions on the base, while in the last case they obey a deformed Laplace equation that contains the squashing parameter of the Berger sphere. This is the generalization to a cosmological context of the usual recipe in ungauged supergravity, where black holes are giv...
Buoyancy and Penrose Process Produce Jets from Rotating Black Holes
Semenov, V S; Heyn, M F
2014-01-01
The exact mechanism by which astrophysical jets are formed is still unknown. It is believed that necessary elements are a rotating (Kerr) black hole and a magnetised accreting plasma. We model the accreting plasma as a collection of magnetic flux tubes/strings. If such a tube falls into a Kerr black hole, then the leading portion loses angular momentum and energy as the string brakes, and to compensate for this loss, momentum and energy is redistributed to the trailing portion of the tube.} {We found that buoyancy creates a pronounced helical magnetic field structure aligned with the spin axis. Along the field lines, the plasma is centrifugally accelerated close to the speed of light. This process leads to unlimited stretching of the flux tube since one part of the tube continues to fall into the black hole and simultaneously the other part of the string is pushed outward. Eventually, reconnection cuts the tube, the inner part is filled with new material and the outer part forms a collimated bubble-structured...
Einstein-charged scalar field theory: black hole solutions and their stability
Ponglertsakul, Supakchai; Winstanley, Elizabeth
2015-01-01
A complex scalar field on a charged black hole in a cavity is known to experience a superradiant instability. We investigate possible final states of this instability. We find hairy black hole solutions of a fully coupled system of Einstein gravity and a charged scalar field. The black holes are surrounded by a reflecting mirror. We also investigate the stability of these black holes.
Accretion Onto a Charged Higher-Dimensional Black Hole
Sharif, M
2016-01-01
This paper deals with the steady-state polytropic fluid accretion onto a higher-dimensional Reissner-Nordstr$\\ddot{o}$m black hole. We formulate the generalized mass flux conservation equation, energy flux conservation and relativistic Bernoulli equation to discuss the accretion process. The critical accretion is investigated by finding critical radius, critical sound velocity and critical flow velocity. We also explore gas compression and temperature profiles to analyze the asymptotic behavior. It is found that the results for Schwarzschild black hole are recovered when $q=0$ in four dimensions. We conclude that accretion process in higher dimensions becomes slower in the presence of charge.
Quasinormal Modes of Charged Black Holes Localized in the Randall-Sundrum Brane World
Soleimani, M J; Radiman, Shahidan; Abdullah, W A T Wan
2016-01-01
We study the quasinormal modes of the massless scalar field of charged black holes embedded in the Randal-Sundrum brane world using the third order WKB approximation. We consider the effects of the electromagnetic and tidal charges on quasinormal frequencies spectrum for charged black hole black holes as well as the effect of the thickness of the bulk.
Rapid growth of superradiant instabilities for charged black holes in a cavity
Herdeiro, Carlos A R; Rúnarsson, Helgi Freyr
2013-01-01
Confined scalar fields, either by a mass term or by a mirror-like boundary condition, have unstable modes in the background of a Kerr black hole. Assuming a time dependence as $e^{-i\\omega t}$, the growth time-scale of these unstable modes is set by the inverse of the (positive) imaginary part of the frequency, Im$(\\omega)$, which reaches a maximum value of the order of Im$(\\omega)M\\sim 10^{-5}$, attained for a mirror-like boundary condition, where $M$ is the black hole mass. In this paper we study the minimally coupled Klein-Gordon equation for a charged scalar field in the background of a Reissner-Nordstr\\"om black hole and show that the unstable modes, due to a mirror-like boundary condition, can grow several orders of magnitude faster than in the rotating case: we have obtained modes with up to Im$(\\omega)M\\sim 0.07$. We provide an understanding, based on an analytic approximation, to why the instability in the charged case has a smaller timescale than in the rotating case. This faster growth, together wi...
Nontopological magnetic monopoles and new magnetically charged black holes
Lee, K; Kimyeong Lee; Erick J Weinberg
1994-01-01
The existence of nonsingular classical magnetic monopole solutions is usually understood in terms of topologically nontrivial Higgs field configurations. We show that finite energy magnetic monopole solutions also exist within a class of purely Abelian gauge theories containing charged vector mesons, even though the possibility of nontrivial topology does not even arise. provided that certain relationships among the parameters of the theory are satisfied. These solutions are singular if these relationships do not hold, but even then become meaningful once the theory is coupled to gravity, for they then give rise to an interesting new class of magnetically charged black holes with hair.
Nontopological magnetic monopoles and new magnetically charged black holes
Lee, Kimyeong; Weinberg, Erick J.
1994-08-01
The existence of nonsingular classical magnetic monopole solutions is usually understood in terms of topologically nontrivial Higgs field configurations. We show that finite energy magnetic monopole solutions also exist within a class of purely Abelian gauge theories containing charged vector mesons, even though the possibility of nontrivial topology does not even arise provided that certain relationships among the parameters of the theory are satisfied. These solutions are singular if these relationships do not hold, but even then become meaningful once the theory is coupled to gravity, for they then give rise to an interesting new class of magnetically charged black holes with hair.
Black hole entropy and Lorentz-diffeomorphism Noether charge
Jacobson, Ted
2015-01-01
We show that, in the first or second order orthonormal frame formalism, black hole entropy is the horizon Noether charge for a combination of diffeomorphism and local Lorentz symmetry involving the Lie derivative of the frame. The Noether charge for diffeomorphisms alone is unsuitable, since a regular frame cannot be invariant under the flow of the Killing field at the bifurcation surface. We apply this formalism to Lagrangians polynomial in wedge products of the frame field 1-form and curvature 2-form, including general relativity, Lovelock gravity, and "topological" terms in four dimensions.
A rotating universe outside a Schwarzschild black hole where spacetime itself non-uniformly rotates
Saw, Vee-Liem
2014-01-01
We study a non-uniformly rotating universe outside a Schwarzschild black hole by generating a time-dependent manifold of revolution around a straight line. In this simple model where layers of spherical shells of the universe non-uniformly rotate, the Einstein field equations require this phenomenon to be caused by a static mass-energy distribution with time-dependent $T^{\\phi\\phi}$ (quadratic with time) and $T^{r\\phi}=T^{\\phi r}$ (linear with time). This indicates that a time-dependent stress along a certain direction results in a spacetime shift in that direction. For this model however, such material violates the null energy condition. Incidentally, the various coordinate systems describing the Schwarzschild solution can be viewed as arising from the freedom in parametrising the straight line and the radial function in the general method of constructing spacetime by generating manifolds of revolution around a given curve.
Charged topological black hole with a conformally coupled scalar field
Martínez, C; Martinez, Cristian; Staforelli, Juan Pablo
2006-01-01
An exact four-dimensional electrically charged topological black hole solution with a conformal coupled self-interacting scalar field is shown. We consider a negative cosmological constant and a quartic self-interaction. According to the mass different causal structures appear, including an extremal black hole. In all cases, the asymptotic region is locally an anti-de Sitter spacetime and a curvature singularity at the origin is present. The scalar field is regular on and outside the event horizon, which is a surface of negative constant curvature. We study the thermodynamical properties for the non-extremal black hole in the grand canonical ensemble. The configurations are thermodynamically stable and do not present phase transitions. The entropy value differs from that which the area law dictates. The non-minimal coupling is responsible for that difference and it can be seen as a modification of the Newton's constant.
Entropy of N-Dimensional Spherically Symmetric Charged Black Hole
Institute of Scientific and Technical Information of China (English)
ZHAO Ren; WU Yue-Qin; ZHANG Li-Chun
2003-01-01
By using the method of quantum statistics, we derive directly the partition functions of bosonic andfermionic fields in the N-dimensional spherically symmetric charged black hole space-time. The statistical entropy ofblack hole is obtained by an improved brick-wall method. When we choose proper parameters in our results, we canobtain that the entropy of black hole is proportional to the area of horizon. In our result, there do not exist neglectedterm and divergent logarithmic term given in the original brick-wall method. We avoid the difficulty in solving the waveequation of scalar and Dirac fields. We offer a simple and direct way of studying entropy of the higher-dimensional black hole.
Strong Gravitational Lensing by the Large R-Charged Non-Extremal Black Hole
Naji, J
2016-01-01
In this paper, gravitational lensing scenario due to the R-charged black hole of five dimensional supergravity investigated. We study the effective potential of traveling photons near the R-charged black hole and find some stable orbits for the photons. We also find that the effect of the black hole charges is increasing of the effective potential. We have shown that photons do not cross the horizon of the very large R-charged black hole. By using the numerical study we find that the black hole charges and non-extremality parameter decrease value of the deflection angle.
The missing asymptotic sector of rotating black-hole spectroscopy
Directory of Open Access Journals (Sweden)
Uri Keshet
2014-10-01
Full Text Available The rotation of a Kerr black hole splits its low-frequency spectrum in two, so it was so far unclear why the known highly-damped resonances show no splitting. We find the missing, split sector, with spin s quasinormal modes approaching the total reflection frequencies ω(n∈N=−ΩΔJ−iκ(n−s, where Ω, κ and ΔJ are the horizon's angular velocity, surface gravity, and induced change in angular momentum. Surprisingly, the new sector is at least partly polar, and corresponds to reversible J transitions. Its fundamental branch converges quickly, possibly affecting gravitational wave signals. A simple interpretation of the Carter constant of motion is proposed.
Spacelike gravitational radiation extraction from rotating binary black holes
Imbiriba, Breno C. O.
2016-07-01
We introduce an alternate method for gravitational radiation extraction for binary black hole mergers where we do not use a single extraction radius at the intermediate field region but instead use a whole spherical shell of three-dimensional (3D) data and continue its evolution using the linearized (Teukolsky) evolution to a final distant radiation extraction radius. We implement this using the Hahndol code for the 3D evolution, and use the “Lazarus” procedure to convert the numerical data into the linearized data. The final waveform is compatible with the ones obtained from the full 3D evolutions with some minor variations that require further study. In the process, we tested the “Lazarus” method with our numerical 3D implementation and gauges showing that even with the advanced gauges suitable for 3D rotating binary evolutions, we recover the same type of limited results obtained in the original work.
Galaxy Rotation and Rapid Supermassive Black Hole Binary Coalescence
Holley-Bockelmann, Kelly
2015-01-01
During a galaxy merger, the supermassive black hole (SMBH) in each galaxy is thought to sink to the center of the potential and form a supermassive black hole binary; this binary can eject stars via 3-body scattering, bringing the SMBHs ever closer. In a static spherical galaxy model, the binary stalls at a separation of about a parsec after ejecting all the stars in its loss cone -- this is the well-known final parsec problem. However it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N larger than 500K, we find that the evolution of the SMBH binary is convergent, and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co...
Conserved charges of black holes in Weyl and Einstein-Gauss-Bonnet gravities
Energy Technology Data Exchange (ETDEWEB)
Peng, Jun-Jin [SEEE, Wuhan Textile University, Institute of Technical Physics, Wuhan, Hubei (China); Chinese Academy of Sciences, Kavli Institute for Theoretical Physics China, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China)
2014-11-15
An off-shell generalization of the Abbott-Deser-Tekin (ADT) conserved charge was recently proposed by Kim et al. They achieved this by introducing off-shell Noether currents and potentials. In this paper, we construct the crucial off-shell Noether current by the variation of the Bianchi identity for the expression of EOM, with the help of the property of Killing vector. Our Noether current, which contains an additional term that is just one half of the Lie derivative of a surface term with respect to the Killing vector, takes a different form in comparison with the one in their work. Then we employ the generalized formulation to calculate the quasi-local conserved charges for the most general charged spherically symmetric and the dyonic rotating black holes with AdS asymptotics in four-dimensional conformal Weyl gravity, as well as the charged spherically symmetric black holes in arbitrary dimensional Einstein-Gauss-Bonnet gravity coupled to Maxwell or nonlinear electrodynamics in AdS spacetime. Our results confirm those obtained through other methods in the literature. (orig.)
Electrostatic self-force of a point charge in non rotating BTZ geometries
Herrera, Y; Santillán, O; Simeone, C
2014-01-01
In the present paper it is studied the electrostatic of charges in non rotating BTZ black holes and wormholes. The particularities of the geometry makes the analysis considerable more complicated than usual electrostatic in a flat geometry. First, these space times are not asymptotically flat but instead asymptotically AdS. In addition, the relative distance d(r,r+1) between two particles located at a radius r and r+1 in the geometry tends to zero when r take large values. This behavior, which is radically different in a flat geometry, changes the analysis of the asymptotic conditions for the electrostatic field. These subtleties are carefully analyzed in the paper. In addition the self-interaction for a static point charge is calculated in a series expansion in a BTZ black hole and also in an wormhole constructed connecting two identical BTZ geometries. The electrostatic self-force is evaluated numerically and compared in both cases. The differences between the self force in both cases is a theoretical exper...
Extremal rotating black holes in the near-horizon limit: Phase space and symmetry algebra
Directory of Open Access Journals (Sweden)
G. Compère
2015-10-01
Full Text Available We construct the NHEG phase space, the classical phase space of Near-Horizon Extremal Geometries with fixed angular momenta and entropy, and with the largest symmetry algebra. We focus on vacuum solutions to d dimensional Einstein gravity. Each element in the phase space is a geometry with SL(2,R×U(1d−3 isometries which has vanishing SL(2,R and constant U(1 charges. We construct an on-shell vanishing symplectic structure, which leads to an infinite set of symplectic symmetries. In four spacetime dimensions, the phase space is unique and the symmetry algebra consists of the familiar Virasoro algebra, while in d>4 dimensions the symmetry algebra, the NHEG algebra, contains infinitely many Virasoro subalgebras. The nontrivial central term of the algebra is proportional to the black hole entropy. The conserved charges are given by the Fourier decomposition of a Liouville-type stress-tensor which depends upon a single periodic function of d−3 angular variables associated with the U(1 isometries. This phase space and in particular its symmetries can serve as a basis for a semiclassical description of extremal rotating black hole microstates.
Damped and zero-damped quasinormal modes of charged, nearly-extremal black holes
Zimmerman, Aaron
2015-01-01
Despite recent progress, the complete understanding of the perturbations of charged, rotating black holes as described by the Kerr-Newman metric remains an open and fundamental problem in relativity. In this study, we explore the existence of families of quasinormal modes of Kerr-Newman black holes whose decay rates limit to zero at extremality, called zero-damped modes in past studies. We review the nearly-extremal and WKB approximation methods for spin-weighted scalar fields (governed by the Dudley-Finley equation) and give an accounting of the regimes where scalar zero-damped and damped modes exist. Using Leaver's continued fraction method, we verify that these approximations give accurate predictions for the frequencies in their regimes of validity. In the non-rotating limit, we argue that gravito-electromagnetic perturbations of nearly-extremal Reissner-Nordstr\\"{o}m black holes have zero-damped modes in addition to the well-known spectrum of damped modes. We provide an analytic formula for the frequenci...
Cosmic Censorship of Rotating Anti-de Sitter Black Hole with a Probe
Gwak, Bogeun
2015-01-01
We test the validity of cosmic censorship in the rotating anti-de Sitter black hole through a particle absorption. For this purpose, we investigate whether the extremal black hole can be overspun by a particle. We construct the particle equations of motions to satisfy the laws of thermodynamics. With the particle absorption, the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid.
Can the Slow-Rotation Approximation be used in Electromagnetic Observations of Black Holes?
Ayzenberg, Dimitry; Yunes, Nicolas
2016-01-01
Future electromagnetic observations of black holes may allow us to test General Relativity in the strong-field regime. Such tests, however, require knowledge of rotating black hole solutions in modified gravity theories, a class of which does not admit the Kerr metric as a solution. Several rotating black hole solutions in modified theories have only been found in the slow-rotation approximation (i.e.~assuming the spin angular momentum is much smaller than the mass squared). We here investigate whether the systematic error due to the approximate nature of these black hole metrics is small enough relative to the observational error to allow their use in electromagnetic observations to constrain deviations from General Relativity. We address this by considering whether electromagnetic observables constructed from a slow-rotation approximation to the Kerr metric can fit observables constructed from the full Kerr metric with systematic errors smaller than current observational errors. We focus on black hole shado...
R-Charged Black Holes and Holographic Optics
Phukon, Prabwal
2013-01-01
We analyze momentum dependent vector modes in the context of gauge theories dual to R-charged black holes in D=4, 5 and 7. For a variety of examples, the master variables are constructed, for which the linearized equations for the perturbations decouple. These allow for the computation of momentum dependent correlation functions. Away from the hydrodynamic limit, numerical analysis using the decoupled equations of motion is used to obtain the analogues of the Depine-Lakhtakia (DL) index. For specified ranges of frequencies, a negative index of refraction is seen to occur in all cases.
Rotating black holes in dilatonic Einstein-Gauss-Bonnet theory.
Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen
2011-04-15
We construct generalizations of the Kerr black holes by including higher-curvature corrections in the form of the Gauss-Bonnet density coupled to the dilaton. We show that the domain of existence of these Einstein-Gauss-Bonnet-dilaton (EGBD) black holes is bounded by the Kerr black holes, the critical EGBD black holes, and the singular extremal EGBD solutions. The angular momentum of the EGBD black holes can exceed the Kerr bound. The EGBD black holes satisfy a generalized Smarr relation. We also compare their innermost stable circular orbits with those of the Kerr black holes and show the existence of differences which might be observable in astrophysical systems.
Numerical study of superradiant instability for charged stringy black hole-mirror system
Li, Ran
2015-01-01
We numerically study the superradiant instability of charged massless scalar field in the background of charged stringy black hole with mirror-like boundary condition. We compare the numerical result with the previous analytical result and show the dependencies of this instability upon various parameters of black hole charge $Q$, scalar field charge $q$, and mirror radius $r_m$. Especially, we have observed that imaginary part of BQN frequencies grows with the scalar field charge $q$ rapidly.
Numerical study of superradiant instability for charged stringy black hole-mirror system
Li, Ran; Zhao, Junkun
2015-01-01
We numerically study the superradiant instability of charged massless scalar field in the background of charged stringy black hole with mirror-like boundary condition. We compare the numerical result with the previous analytical result and show the dependencies of this instability upon various values of black hole charge Q, scalar field charge q, and mirror radius rm. Especially, we have observed that imaginary part of BQN frequencies grows with the scalar field charge q rapidly.
Numerical study of superradiant instability for charged stringy black hole–mirror system
Li, Ran; Zhao, Junkun
2015-01-01
We numerically study the superradiant instability of charged massless scalar field in the background of charged stringy black hole with mirror-like boundary condition. We compare the numerical result with the previous analytical result and show the dependencies of this instability upon various values of black hole charge Q , scalar field charge q , and mirror radius rm . Especially, we have observed that imaginary part of BQN frequencies grows with the scalar field charge q rapidly.
Numerical study of superradiant instability for charged stringy black hole–mirror system
Directory of Open Access Journals (Sweden)
Ran Li
2015-01-01
Full Text Available We numerically study the superradiant instability of charged massless scalar field in the background of charged stringy black hole with mirror-like boundary condition. We compare the numerical result with the previous analytical result and show the dependencies of this instability upon various values of black hole charge Q, scalar field charge q, and mirror radius rm. Especially, we have observed that imaginary part of BQN frequencies grows with the scalar field charge q rapidly.
Growth of black holes in the interior of rotating neutron stars
DEFF Research Database (Denmark)
Kouvaris, C.; Tinyakov, P.
2014-01-01
Mini-black holes made of dark matter that can potentially form in the interior of neutron stars always have been thought to grow by accreting the matter of the core of the star via a spherical Bondi accretion. However, neutron stars have sometimes significant angular velocities that can...... in principle stall the spherical accretion and potentially change the conclusions derived about the time it takes for black holes to destroy a star. We study the effect of the star rotation on the growth of such black holes and the evolution of the black hole spin. Assuming no mechanisms of angular momentum...... evacuation, we find that even moderate rotation rates can in fact destroy spherical accretion at the early stages of the black hole growth. However, we demonstrate that the viscosity of nuclear matter can alleviate the effect of rotation, making it possible for the black hole to maintain spherical accretion...
Liu, Hang
2016-01-01
In this paper, we investigate the angular momentum independence of the entropy sum and product for AdS rotating black holes based on the first law of thermodynamics and a mathematical lemma related to Vandermonde determinant. The advantage of this method is that the explicit forms of the spacetime metric, black hole mass and charge are not needed but the Hawking temperature and entropy formula on the horizons are necessary for static black holes, while our calculations require the expressions of metric and angular velocity formula. We find that the entropy sum is always independent of angular momentum for all dimensions and the angular momentum-independence of entropy product only holds for the dimensions $d>4$ with at least one rotation parameter $a_i=0$, while the mass-free of entropy sum and entropy product for rotating black holes only stand for higher dimensions ($d>4$) and for all dimensions, respectively. On the other hand, we find that the introduction of a negative cosmological constant does not affe...
Liu, Hang; Meng, Xin-he
2016-08-01
In this paper, we investigate the angular momentum independence of the entropy sum and product for AdS rotating black holes based on the first law of thermodynamics and a mathematical lemma related to Vandermonde determinant. The advantage of this method is that the explicit forms of the spacetime metric, black hole mass and charge are not needed but the Hawking temperature and entropy formula on the horizons are necessary for static black holes, while our calculations require the expressions of metric and angular velocity formula. We find that the entropy sum is always independent of angular momentum for all dimensions and the angular momentum-independence of entropy product only holds for the dimensions d > 4 with at least one rotation parameter ai = 0, while the mass-free of entropy sum and entropy product for rotating black holes only stand for higher dimensions (d > 4) and for all dimensions, respectively. On the other hand, we find that the introduction of a negative cosmological constant does not affect the angular momentum-free of entropy sum and product but the criterion for angular momentum-independence of entropy product will be affected.
Directory of Open Access Journals (Sweden)
Hang Liu
2016-08-01
Full Text Available In this paper, we investigate the angular momentum independence of the entropy sum and product for AdS rotating black holes based on the first law of thermodynamics and a mathematical lemma related to Vandermonde determinant. The advantage of this method is that the explicit forms of the spacetime metric, black hole mass and charge are not needed but the Hawking temperature and entropy formula on the horizons are necessary for static black holes, while our calculations require the expressions of metric and angular velocity formula. We find that the entropy sum is always independent of angular momentum for all dimensions and the angular momentum-independence of entropy product only holds for the dimensions d>4 with at least one rotation parameter ai=0, while the mass-free of entropy sum and entropy product for rotating black holes only stand for higher dimensions (d>4 and for all dimensions, respectively. On the other hand, we find that the introduction of a negative cosmological constant does not affect the angular momentum-free of entropy sum and product but the criterion for angular momentum-independence of entropy product will be affected.
Charge Orbits of Extremal Black Holes in Five Dimensional Supergravity
Cerchiai, Bianca L; Marrani, Alessio; Zumino, Bruno
2010-01-01
We derive the U-duality charge orbits, as well as the related moduli spaces, of "large" and "small" extremal black holes in non-maximal ungauged Maxwell-Einstein supergravities with symmetric scalar manifolds in d=5 space-time dimensions. The stabilizer groups of the various classes of orbits are obtained by determining and solving suitable U-invariant sets of constraints, both in "bare" and "dressed" charges bases, with various methods. After a general treatment of attractors in real special geometry (also considering non-symmetric cases), the N=2 "magic" theories, as well as the N=2 Jordan symmetric sequence, are analyzed in detail. Finally, the half-maximal (N=4) matter-coupled supergravity is also studied in this context.
Thermodynamics of charged Lifshitz black holes with quadratic corrections
Bravo-Gaete, Moises
2015-01-01
In arbitrary dimension, we consider the Einstein-Maxwell Lagrangian supplemented by the more general quadratic-curvature corrections. For this model, we derive four classes of charged Lifshitz black hole solutions for which the metric function is shown to depend on a unique integration constant. The masses of these solutions are computed using the quasilocal formalism based on the relation established between the off-shell ADT and Noether potentials. Among these four solutions, three of them are interpreted as extremal in the sense that their mass vanishes identically. For the last family of solutions, the quasilocal mass and the electric charge both are shown to depend on the integration constant. Finally, we verify that the first law of thermodynamics holds for each solution and a Smarr formula is also established for the four solutions.
Magnetically-charged black branes and viscosity/entropy ratios
Liu, Hai-Shan; Lü, H.; Pope, C. N.
2016-12-01
We consider asymptotically-AdS n-dimensional black brane solutions in a theory of gravity coupled to a set of N p-form field strengths, in which the field strengths carry magnetic charges. For appropriately chosen charges, the metrics are isotropic in the ( n - 2) transverse directions. However, in general the field strength configurations break the full Euclidean symmetry of the ( n - 2)-dimensional transverse space, and the shear viscosity tensor in the dual theory is no longer isotropic. We study the linearised equations for transverse traceless metric perturbations in these backgrounds, and by employing the Kubo formula we obtain expressions for the ratios η/S of the shear viscosity components divided by the entropy density. We find that the KSS bound on the ratios η/S is generally violated in these solutions. We also extend the discussion by including a dilatonic scalar field in the theory, leading to solutions that are asymptotically Lifshitz with hyperscaling violation.
BlackMax: A black-hole event generator with rotation, recoil, split branes, and brane tension
Dai, De-Chang; Starkman, Glenn; Stojkovic, Dejan; Issever, Cigdem; Rizvi, Eram; Tseng, Jeff
2008-04-01
We present a comprehensive black-hole event generator, BlackMax, which simulates the experimental signatures of microscopic and Planckian black-hole production and evolution at the LHC in the context of brane world models with low-scale quantum gravity. The generator is based on phenomenologically realistic models free of serious problems that plague low-scale gravity, thus offering more realistic predictions for hadron-hadron colliders. The generator includes all of the black-hole gray-body factors known to date and incorporates the effects of black-hole rotation, splitting between the fermions, nonzero brane tension, and black-hole recoil due to Hawking radiation (although not all simultaneously). The generator can be interfaced with Herwig and Pythia. The main code can be downloaded from http://www-pnp.physics.ox.ac.uk/~issever/BlackMax/blackmax.html.
Gußmann, Alexander
2016-01-01
The existence of classical solutions of the Einstein-Yang-Mills-Higgs equations describing black holes inside 't Hooft-Polyakov magnetic monopoles implies that not all stationary magnetically charged black holes can be uniquely described by their asymptotic characteristics. In fact, in a certain domain of parameters, there exist different spherically-symmetric, non-rotating and asymptotically-flat classical black hole solutions of the Einstein-Yang-Mills-Higgs equations which have the same ADM mass and the same magnetic charge but significantly different geometries in the near-horizon regions. (These are black hole solutions which are described by a Reissner-Nordstr\\"om metric on the one hand and the "magnetic monopole black hole solutions" which can be interpreted as black holes inside 't Hooft-Polyakov magnetic monopoles described by a metric which is not of Reissner-Nordstr\\"om form on the other hand.) One can experimentally distinguish such black holes with same asymptotic characteristics but different ne...
On the resonances of a rotating black hole analogue
Dolan, Sam R; Crispino, Luís C B
2011-01-01
Under certain conditions, sound waves in a fluid may be governed by a Klein-Gordon equation on an `effective spacetime' determined by the background flow properties. Here we study the `draining bathtub' (DBT) system, a circulating, draining flow whose effective spacetime has key features in common with the rotating black hole (Kerr) spacetime. We investigate the spectrum of quasinormal (QN) mode and Regge pole resonances exhibited by the DBT, and we compare with the equivalent Kerr spectra. First, to demonstrate the ubiquity of `QN ringing', we simulate the evolution of a perturbation in the time domain by applying a finite-difference method. Next, we solve the wave equation in the frequency domain, using the continued-fraction method to compute QN frequencies. We explore the geometric link between null geodesic orbits and QN frequencies, and apply an asymptotic method to provide an expansion of QN frequencies in inverse powers of mode number $m$. The same range of methods is then applied to study the (closel...
Quasinormal modes and stability of the rotating acoustic black hole: numerical analysis
Cardoso, V; Yoshida, S; Cardoso, Vitor; Lemos, Jose' P. S.; Yoshida, Shijun
2004-01-01
The study of the quasinormal modes (QNMs) of the 2+1 dimensional rotating draining bathtub acoustic black hole, the closest analogue found so far to the Kerr black hole, is performed. Both the real and imaginary parts of the quasinormal (QN) frequencies as a function of the rotation parameter B are found through a full non-linear numerical analysis. Since there is no change in sign in the imaginary part of the frequency as B is increased we conclude that the 2+1 dimensional rotating draining bathtub acoustic black hole is stable against small perturbations.
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emek Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)
2015-07-15
It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ{sub gap}/τ{sub emission} = O(1), where τ{sub gap} is the average time gap between the emissions of successive Hawking quanta and τ{sub emission} is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)
Time Delay in Gravitational Lensing by a Charged Black Hole of String Theory
Rubio, E A L
2003-01-01
We calculate the time delay between different relativistic images formed by the gravitational lensing produced by the Gibbons-Maeda-Garfinkle-Horowitz-Stromiger (GMGHS) charged black hole of heterotic string theory. Modeling the supermassive central objects of some galaxies as GMGHS black holes, numerical values of the time delays are estimated and compared with the correspondient Reissner-Nordstrom black holes . The time difference amounts to hours, thus being measurable and permiting to distinguish between General Relativity and String Theory charged black holes.
BlackMax: A black-hole event generator with rotation, recoil, split branes and brane tension
Dai, De-Chang; Stojkovic, Dejan; Issever, Cigdem; Rizvi, Eram; Tseng, Jeff
2007-01-01
We present a comprehensive black-hole event generator, BlackMax, which simulates the experimental signatures of microscopic and Planckian black-hole production and evolution at the LHC in the context of brane world models with low-scale quantum gravity. The generator is based on phenomenologically realistic models free of serious problems that plague low-scale gravity, thus offering more realistic predictions for hadron-hadron colliders. The generator includes all of the black-hole graybody factors known to date and incorporates the effects of black-hole rotation, splitting between the fermions, non-zero brane tension and black-hole recoil due to Hawking radiation (although not all simultaneously). The generator can be interfaced with Herwig and Pythia.
Dai, De-Chang; Rizvi, Eram; Starkman, Glenn; Stojkovic, Dejan; Tseng, Jeff
2009-01-01
This is the users manual of the black-hole event generator BlackMax, which simulates the experimental signatures of microscopic and Planckian black-hole production and evolution at proton-proton, proton-antiproton and electron-positron colliders in the context of brane world models with low-scale quantum gravity. The generator is based on phenomenologically realistic models free of serious problems that plague low-scale gravity. It includes all of the black-hole gray-body factors known to date and incorporates the effects of black-hole rotation, splitting between the fermions, non-zero brane tension and black-hole recoil due to Hawking radiation (although not all simultaneously).
Floating and sinking: the imprint of massive scalars around rotating black holes.
Cardoso, Vitor; Chakrabarti, Sayan; Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo
2011-12-09
We study the coupling of massive scalar fields to matter in orbit around rotating black holes. It is generally expected that orbiting bodies will lose energy in gravitational waves, slowly inspiraling into the black hole. Instead, we show that the coupling of the field to matter leads to a surprising effect: because of superradiance, matter can hover into "floating orbits" for which the net gravitational energy loss at infinity is entirely provided by the black hole's rotational energy. Orbiting bodies remain floating until they extract sufficient angular momentum from the black hole, or until perturbations or nonlinear effects disrupt the orbit. For slowly rotating and nonrotating black holes floating orbits are unlikely to exist, but resonances at orbital frequencies corresponding to quasibound states of the scalar field can speed up the inspiral, so that the orbiting body sinks. These effects could be a smoking gun of deviations from general relativity.
Floating and sinking: the imprint of massive scalars around rotating black holes
Cardoso, Vitor; Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo
2011-01-01
We study the coupling of massive scalar fields to matter in orbit around rotating black holes. It is generally expected that orbiting bodies will lose energy in gravitational waves, slowly inspiralling into the black hole. Instead, we show that the coupling of the field to matter leads to a surprising effect: because of superradiance, matter can hover into "floating orbits" for which the net gravitational energy loss at infinity is entirely provided by the black hole's rotational energy. Orbiting bodies remain floating until they extract sufficient angular momentum from the black hole, or until perturbations or nonlinear effects disrupt the orbit. For slowly rotating and nonrotating black holes floating orbits are unlikely to exist, but resonances at orbital frequencies corresponding to quasibound states of the scalar field can speed up the inspiral, so that the orbiting body "sinks". These effects could be a smoking gun of deviations from general relativity.
Properties of CFTs dual to charged BTZ black hole
Energy Technology Data Exchange (ETDEWEB)
Maity, Debaprasad, E-mail: debu@imsc.res.i [The Institute of Mathematical Sciences, Taramani, Chennai 600113 (India); Sarkar, Swarnendu, E-mail: ssarkar@physics.du.ac.i [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Sathiapalan, B., E-mail: bala@imsc.res.i [The Institute of Mathematical Sciences, Taramani, Chennai 600113 (India); Shankar, R., E-mail: shankar@imsc.res.i [The Institute of Mathematical Sciences, Taramani, Chennai 600113 (India); Sircar, Nilanjan, E-mail: nilanjan@imsc.res.i [The Institute of Mathematical Sciences, Taramani, Chennai 600113 (India)
2010-11-11
We study properties of strongly coupled CFT's with non-zero background electric charge in 1+1 dimensions by studying the dual gravity theory-which is a charged BTZ black hole. Correlators of operators dual to scalars, gauge fields and fermions are studied at both T=0 and T{ne}0. In the T=0 case we are also able to compare with analytical results based on AdS{sub 2} and find reasonable agreement. In particular the correlation between log periodicity and the presence of finite spectral density of gapless modes is seen. The real part of the conductivity (given by the current-current correlator) also vanishes as {omega}{yields}0 as expected. The fermion Green's function shows quasiparticle peaks with approximately linear dispersion but the detailed structure is neither Fermi liquid nor Luttinger liquid and bears some similarity to a 'Fermi-Luttinger' liquid. This is expected since there is a background charge and the theory is not Lorentz or scale invariant. A boundary action that produces the observed non-Luttinger liquid like behavior (k-independent non-analyticity at {omega}=0) in the Green's function is discussed.
A new metric for rotating black holes in Gauss-Bonnet gravity
Institute of Scientific and Technical Information of China (English)
Yue Rui-Hong; Zou De-Cheng; Yu Tian-Yi; Yang Zhan-Ying
2011-01-01
This paper presents a new metric and studies slowly rotating Gauss-Bonnet black holes with a nonvanishing angular momentum in five dimensional anti-de Sitter spaces. Taking the angular momentum parameter a up to second order, the slowly rotating black hole solutions are obtained by working directly in the action. In addition, it also finds that this method is applicable in higher order Lovelock gravity.
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
Energy Technology Data Exchange (ETDEWEB)
Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)
2015-09-15
We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.
THERMODYNAMICS OF THE SLOWLY ROTATING KERR-NEWMAN BLACK HOLE IN THE GRAND CANONICAL ENSEMBLE
Institute of Scientific and Technical Information of China (English)
CHEN JU-HUA; JING JI-LIANG
2001-01-01
We investigate the thermodynamics of the slowly rotating Kerr-Newman (K-N) black hole in the grand canonical ensemble with York's formalism. Some thermodynamical properties, such as the thermodynamical action, entropy,thermodynamical energy and heat capacity are studied, and solutions of the slowly rotating K-N black hole with different boundary conditions are analysed. We find stable solutions and instantons under certain boundary conditions.
Superradiant instability of charged scalar field in stringy black hole mirror system
Li, Ran; Zhao, Junkun
2014-01-01
It has been shown that the mass of a charged scalar field in the background of a charged stringy black hole is never able to generate a potential well outside the event horizon to trap the superradiant modes. This is to say that the charged stringy black hole is stable against massive charged scalar perturbations. In this paper we will study the superradiant instability of the massless scalar field in the background of charged stringy black hole due to a mirror-like boundary condition. The an...
On a general class of regular rotating black holes based on a smeared mass distribution
Directory of Open Access Journals (Sweden)
Alexis Larranaga
2015-04-01
Full Text Available In this work we investigate the behavior of a new general class of rotating regular black holes based on a non-Gaussian smeared mass distribution. It is shown that the existence of a fundamental minimal length cures the well-known problems in the terminal phase of black hole evaporation, since we find that there is a finite maximum temperature that the black hole reaches before cooling down to absolute zero, so that the evaporation ends up in a zero temperature extremal black hole whose mass and size depends on the value of the fundamental length and on the rotation parameter of the black hole. We also study the geodesic structure in these spacetimes and calculate the shadows that these black holes produce.
No-go theorem for slowly rotating black holes in Hořava-Lifshitz gravity.
Barausse, Enrico; Sotiriou, Thomas P
2012-11-02
We consider slowly rotating, stationary, axisymmetric black holes in the infrared limit of Hořava-Lifshitz gravity. We show that such solutions do not exist, provided that they are regular everywhere apart from the central singularity. This has profound implications for the viability of the theory, considering the astrophysical evidence for the existence of black holes with nonzero spin.
Synchrotron and Smith-Purcell radiations from a charge rotating around a cylindrical grating
Saharian, A A; Mkrtchyan, A R; Khachatryan, B V
2016-01-01
We investigate the radiation from a charge rotating around conductors with cylindrical symmetry. First the problem is considered with a charge rotating around a conducting cylinder immersed in a homogeneous medium. The surface charge and current densities induced on the cylinder surface are evaluated. A formula is derived for the spectral-angular density of the radiation intensity. In the second part, we study the radiation for a charge rotating around a diffraction grating on a cylindrical surface with metallic strips parallel to the cylinder axis. The effect of the grating on the radiation intensity is approximated by the surface currents induced on the strips by the field of the rotating charge. The expressions are derived for the electric and magnetic fields and for the angular density of the radiation intensity on a given harmonic. We show that the interference between the synchrotron and Smith-Purcell radiations may lead to interesting features. In particular, the behavior of the radiation intensity on ...
Hawking emission of gravitons in higher dimensions: non-rotating black holes
Cardoso, V; Gualtieri, L; Cardoso, Vitor; Cavaglia, Marco; Gualtieri, Leonardo
2006-01-01
We compute the absorption cross section and the total power carried by gravitons in the evaporation process of a higher-dimensional non-rotating black hole. These results are applied to a model of extra dimensions with standard model fields propagating on a brane. The emission of gravitons in the bulk is highly enhanced as the spacetime dimensionality increases. If the black hole is rotating, graviton loss is likely to dominate the emission spectrum. The implications for the detection of black holes in particle colliders and ultrahigh-energy cosmic ray air showers are briefly discussed.
Joule-Thomson expansion of the charged AdS black holes
Ökcü, Özgür; Aydıner, Ekrem
2017-01-01
In this paper, we study Joule-Thomson effects for charged AdS black holes. We obtain inversion temperatures and curves. We investigate similarities and differences between van der Waals fluids and charged AdS black holes for the expansion. We obtain isenthalpic curves for both systems in the T- P plane and determine the cooling-heating regions.
Joule-Thomson Expansion of Charged AdS Black Holes
Ökcü, Özgür
2016-01-01
In this paper, we study Joule-Thomson effects for charged AdS black holes. We obtain inversion temperatures and curves. We investigate similarities and differences between van der Waals fluids and charged AdS black holes for the expansion. We obtain isenthalpic curves for both systems in $T-P$ plane and determine the cooling-heating regions.
Near horizon data and physical charges of extremal AdS black holes
Astefanesei, D.; Banerjee, N.; Dutta, S.
2011-01-01
We compute the physical charges and discuss the properties of a large class of five-dimensional extremal AdS black holes by using the near horizon data. Our examples include baryonic and electromagnetic black branes, as well as supersymmetric spinning black holes. In the presence of the gauge Chern–
Holographic phase transitions from higgsed, non abelian charged black holes
Giordano, Gaston L
2015-01-01
We find solutions of a gravity-Yang-Mills-Higgs theory in four dimensions that represent asymptotic anti-de Sitter charged black holes with partial/full gauge symmetry breaking. We then apply the AdS/CFT correspondence to study the strong coupling regime of a $2+1$ quantum field theory at temperature $T$ and finite chemical potential, which undergoes transitions to phases exhibiting the condensation of a composite charged vector operator below a critical temperature $T_c$, presumably describing $p+ip/p$-wave superconductors. In the case of $p+ip$-wave superconductors the transitions are always of second order. But for $p$-wave superconductors we determine the existence of a critical value $\\alpha_c$ of the gravitational coupling (for fixed Higgs v.e.v. parameter $\\hat m_W$) beyond which the transitions become of first order. As a by-product, we show that the $p$-wave phase is energetically favored over the $p+ip$ one, for any values of the parameters. Finally we find the ground state solutions corresponding t...
Electromagnetic quasinormal modes of rotating black strings and the AdS/CFT correspondence
Morgan, Jaqueline; Zanchin, Vilson T
2013-01-01
We investigate the quasinormal spectrum of electromagnetic perturbations of rotating black strings. Among the solutions of Einstein equations in the presence of a negative cosmological constant there are asymptotically anti-de Sitter (AdS) black holes whose horizons have the topology of a cylinder. The stationary version of these AdS black holes represents rotating black strings. The conformal field theory (CFT) dual of a black string lives in a Minkowski space with a compact dimension. On the basis of the AdS/CFT duality, we interpret a CFT plasma moving with respect to the preferred rest frame introduced by the topology as the holographic dual to a rotating black string. We explore the consequences of this correspondence by investigating the electromagnetic perturbations of a black string for different rotation parameter values. As usual the electromagnetic quasinormal modes (QNM) correspond to the poles of retarded Green's functions of $R$-symmetry currents in the boundary field theory. The hydrodynamic re...
Superradiant instability of charged scalar field in stringy black hole mirror system
Energy Technology Data Exchange (ETDEWEB)
Li, Ran; Zhao, Junkun [Henan Normal University, Department of Physics, Xinxiang (China)
2014-09-15
It has been shown that the mass of a charged scalar field in the background of a charged stringy black hole is never able to generate a potential well outside the event horizon to trap the superradiant modes. This is to say that the charged stringy black hole is stable against massive charged scalar perturbations. In this paper we will study the superradiant instability of the massless scalar field in the background of charged stringy black hole due to a mirror-like boundary condition. The analytical expression of the frequencies of unstable superradiant modes is derived by using the asymptotic matching method. It is also pointed out that the black hole mirror system becomes extremely unstable for a large charge q of the scalar field and a small mirror radius r{sub m}. (orig.)
Reentrant Phase Transitions in Rotating AdS Black Holes
Altamirano, Natacha; Mann, Robert B
2013-01-01
We study the thermodynamics of higher-dimensional singly spinning asymptotically AdS black holes in the canonical (fixed J) ensemble of extended phase space, where the cosmological constant is treated as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Along with the usual small/large black hole phase transition, we find a new phenomenon of reentrant phase transitions for all d>5 dimensions, in which a monotonic variation of the temperature yields two phase transitions from large to small and back to large black holes. This situation is similar to that seen in multicomponent liquids.
Entropy spectrum of charged BTZ black holes in massive gravity's rainbow
Panah, Behzad Eslam
2016-01-01
Regarding the significant interests in massive gravity's rainbow and also BTZ black holes, we apply the formalism introduced by Jiang and Han in order to investigate the quantization of the entropy of black holes. We show that the entropy of BTZ black holes in massive gravity's rainbow is quantized with equally spaced spectra and it depends on the value of the parameters of this black hole such as; massive parameters, electrical charge, the cosmological constant and also rainbow functions.
Analytic treatment of the system of a Kerr-Newman black hole and a charged massive scalar field
Hod, Shahar
2016-01-01
Charged rotating Kerr-Newman black holes are known to be superradiantly unstable to perturbations of charged massive bosonic fields whose proper frequencies lie in the bounded regime $0 < \\omega < \\text{min} \\{\\omega_{\\text{c}} \\equiv m \\Omega_{\\text{H}} + q\\Phi_{\\text{H}},\\mu\\}$ [here $\\{\\Omega_{\\text{H}}, \\Phi_{\\text{H}}\\}$ are respectively the angular velocity and electric potential of the Kerr-Newman black hole, and $\\{m,q,\\mu\\}$ are respectively the azimuthal harmonic index, the charge coupling constant, and the proper mass of the field]. In this paper we study analytically the complex resonance spectrum which characterizes the dynamics of linearized charged massive scalar fields in a near-extremal Kerr-Newman black-hole spacetime. Interestingly, it is shown that near the critical frequency $\\omega_{\\text{c}}$ for superradiant amplification and in the eikonal large-mass regime, the superradiant instability growth rates of the explosive scalar fields are characterized by a non-trivial (non-monotonic...
Electrostatics in the Surroundings of a Topologically Charged Black Hole in the Brane
Directory of Open Access Journals (Sweden)
Alexis Larrañaga
2014-01-01
Full Text Available We determine the expression for the electrostatic potential generated by a point charge held stationary in the topologically charged black hole spacetime arising from the Randall-Sundrum II braneworld model. We treat the static electric point charge as a linear perturbation on the black hole background and an expression for the electrostatic multipole solution is given: PACS: 04.70.-s, 04.50.Gh, 11.25.-w, 41.20.-q, 41.90.+e.
Rotating "Black Holes" with Holes in the Horizon
Burinskii, Alexander; Elizalde, Emilio; Hildebrandt, Sergi R.; Magli, Giulio
2005-01-01
Kerr-Schild solutions of the Einstein-Maxwell field equations, containing semi-infinite axial singular lines, are investigated. It is shown that axial singularities break up the black hole, forming holes in the horizon. As a result, a tube-like region appears which allows matter to escape from the interior without crossing the horizon. It is argued that axial singularities of this kind, leading to very narrow beams, can be created in black holes by external electromagnetic or gravitational ex...
Strong gravitational lensing in a rotating Kaluza-Klein black hole with squashed horizons
Ji, LiYong; Jing, Jiliang
2014-01-01
We have investigated the strong gravitational lensing in a rotating squashed Kaluza-Klein (KK) black hole spacetime. Our result show that the strong gravitational lensings in the rotating squashed KK black hole spacetime have some distinct behaviors from those in the backgrounds of the four-dimensional Kerr black hole and of the squashed KK G\\"{o}del black hole. In the rotating squashed KK black hole spacetime, the marginally circular photon radius $\\rho_{ps}$, the coefficient $\\bar{a}$, $\\bar{b}$, the deflection angle $\\alpha(\\theta)$ in the $\\phi$ direction and the corresponding observational variables are independent of whether the photon goes with or against the rotation of the background, which is different with those in the usual four-dimensional Kerr black hole spacetime. Moreover, we also find that with the increase of the scale of extra dimension $\\rho_0$, the marginally circular photon radius $\\rho_{ps}$ and the angular position of the relativistic images $\\theta_\\infty$ first decreases and then inc...
Charge Loss (or the Lack Thereof) for AdS Black Holes
Ong, Yen Chin
2014-01-01
The evolution of evaporating charged black holes is complicated to model in general, but is nevertheless important since the hints to the Information Loss Paradox and its recent firewall incarnation may lie in understanding more generic geometries than that of Schwarzschild spacetime. Fortunately, for sufficiently large asymptotically flat Reissner-Nordstrom black holes, the evaporation process can be modeled via a system of coupled linear ordinary differential equations, with charge loss rate governed by Schwinger pair-production process. The same model can be generalized to study the evaporation of AdS Reissner-Nordstrom black holes with flat horizon. It was recently found that such black holes always evolve towards extremality since charge loss is inefficient. This property is completely opposite to the asymptotically flat case in which the black hole eventually loses its charges and tends towards Schwarzschild limit. We clarify the underlying reason for this different behavior.
Holographic phase transitions from higgsed, non abelian charged black holes
Giordano, Gastón L.; Lugo, Adrián R.
2015-07-01
We find solutions of a gravity-Yang-Mills-Higgs theory in four dimensions that represent asymptotic anti-de Sitter charged black holes with partial/full gauge symme-try breaking. We then apply the AdS/CFT correspondence to study the strong coupling regime of a 2 + 1 quantum field theory at temperature T and finite chemical potential, which undergoes transitions to phases exhibiting the condensation of a composite charged vector operator below a critical temperature T c , presumably describing p + ip/p-wave su-perconductors. In the case of p + ip-wave superconductors the transitions are always of second order. But for p-wave superconductors we determine the existence of a critical value αc of the gravitational coupling (for fixed Higgs v.e.v. parameter ) beyond which the transitions become of first order. As a by-product, we show that the p-wave phase is energetically favored over the p + ip one, for any values of the parameters. We also find the ground state solutions corresponding to zero temperature. Such states are described by domain wall geometries that interpolate between AdS 4 spaces with different light veloc-ities, and for a given , they exist below a critical value of the coupling. The behavior of the order parameter as function of the gravitational coupling near the critical coupling suggests the presence of second order quantum phase transitions. We finally study the dependence of the solution on the Higgs coupling, and find the existence of a critical value beyond which no condensed solution is present.
Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo
2013-09-01
In Einstein-Maxwell theory, according to classic uniqueness theorems, the most general stationary black-hole solution is the axisymmetric Kerr-Newman metric, which is defined by three parameters: mass, spin and electric charge. The radial and angular dependence of gravitational and electromagnetic perturbations in the Kerr-Newman geometry do not seem to be separable. In this paper we circumvent this problem by studying scalar, electromagnetic and gravitational perturbations of Kerr-Newman black holes in the slow-rotation limit. We extend (and provide details of) the analysis presented in a recent Letter [P. Pani, E. Berti, and L. Gualtieri, Phys. Rev. Lett. 110, 241103 (2013)]. Working at linear order in the spin, we present the first detailed derivation of the axial and polar perturbation equations in the gravito-electromagnetic case, and we compute the corresponding quasinormal modes for any value of the electric charge. Our study is the first self-consistent stability analysis of the Kerr-Newman metric, and in principle it can be extended to any order in the small rotation parameter. We find numerical evidence that the axial and polar sectors are isospectral at first order in the spin and speculate on the possible implications of this result.
Superradiant instability of the charged scalar field in stringy black hole mirror system
Li, Ran
2014-01-01
It has been shown that the mass of the scalar field in the charged stringy black hole is never able to generate a potential well outside the event horizon to trap the superradiant modes. This is to say that the charged stringy black hole is stable against the massive charged scalar perturbation. In this paper we will study the superradiant instability of the massless scalar field in the background of charged stringy black hole due to a mirror-like boundary condition. The analytical expression of the unstable superradiant modes is derived by using the asymptotic matching method. It is also pointed out that the black hole mirror system becomes extremely unstable for a large charge $q$ of scalar field and the small mirror radius $r_m$.
Conserved charges, surface degrees of freedom, and black hole entropy
Seraj, Ali
2016-01-01
In this thesis, we study the Hamiltonian and covariant phase space description of gravitational theories. The phase space represents the allowed field configurations and is accompanied by a closed nondegenerate 2 form- the symplectic form. We will show that local/gauge symmetries of the action fall into two different categories in the phase space formulation. Those corresponding to constraints in the phase space, and those associated with nontrivial conserved charges. We argue that while the former is related to redundant gauge degrees of freedom, the latter leads to physically distinct states of the system, known as surface degrees of freedom and can induce a lower dimensional dynamics on the system. These ideas are then implemented to build the phase space of specific gravitational systems: 1) asymptotically AdS3 spacetimes, and 2) near horizon geometries of extremal black holes (NHEG) in arbitrary dimension. In the AdS3 phase space, we show that Brown-Henneaux asymptotic symmetries can be extended inside t...
Zhang, Bing
2016-08-01
The discoveries of GW150914, GW151226, and LVT151012 suggest that double black hole (BH-BH) mergers are common in the universe. If at least one of the two merging black holes (BHs) carries a certain amount of charge, possibly retained by a rotating magnetosphere, the inspiral of a BH-BH system would drive a global magnetic dipole normal to the orbital plane. The rapidly evolving magnetic moment during the merging process would drive a Poynting flux with an increasing wind power. The magnetospheric activities during the final phase of the merger would make a fast radio burst (FRB) if the BH charge can be as large as a factor of \\hat{q}˜ ({10}-9{--}{10}-8) of the critical charge Q c of the BH. At large radii, dissipation of the Poynting flux energy in the outflow would power a short-duration high-energy transient, which would appear as a detectable short-duration gamma-ray burst (GRB) if the charge can be as large as \\hat{q}˜ ({10}-5{--}{10}-4). The putative short GRB coincident with GW150914 recorded by Fermi GBM may be interpreted with this model. Future joint GW/GRB/FRB searches would lead to a measurement or place a constraint on the charges carried by isolate BHs.
The generalization of charged AdS black hole specific volume and number density
Wang, Zi-Liang; He, Miao; Fang, Chao; Sun, Dao-Quan; Deng, Jian-Bo
2017-04-01
In this paper, by proposing a generalized specific volume, we restudy the P- V criticality of charged AdS black holes in the extended phase space. The results show that most of the previous conclusions can be generalized without change, but the ratio {\\tilde{ρ }}_c should be 3 {\\tilde{α }}/16 in general case. Further research on the thermodynamical phase transition of black hole leads us to a natural interpretation of our assumption, and more black hole properties can be generalized. Finally, we study the number density for charged AdS black hole in higher dimensions, the results show the necessity of our assumption.
Strong Gravitational Lensing in a Charged Squashed Kaluza- Klein G\\"{o}del Black hole
Sadeghi, J
2013-01-01
In this paper we investigate the strong gravitational lansing in a charged squashed Kaluza-Klein G\\"{o}del black hole. The deflection angle is considered by the logarithmic term proposed by Bozza et al. Then we study the variation of deflection angle and its parameters $\\bar{a}$ and $\\bar{b}$ . We suppose that the supermassive black hole in the galaxy center can be considered by a charged squashed Kaluza-Klein black hole in a G\\"{o}del background and by relation between lensing parameters and observables we estimate the observables for different values of charge, extra dimension and G\\"{o}del parameters.
Scalar Perturbations on the background of Linearly and Nonlinearly Charged BTZ Black Holes
Tang, Zi-Yu; Zangeneh, Mahdi Kord; Wang, Bin; Saavedra, Joel
2016-01-01
We investigate the spacetime properties of BTZ black holes in Maxwell field and BornInfeld field and find rich properties in the spacetime structures when the model parameters vary. Employing the Landau-Lifshitz theory, we examine the thermodynamical phase transition in the charged BTZ holes. We further study the dynamical perturbation in the background of the charged BTZ black holes and find different properties of dynamical perturbations for the extreme and nonextreme charged BTZ black holes, which can serve as a new physical signal to indicate the phase transition between them.
Testing gravity of a regular and slowly rotating phantom black hole by quasi-periodic oscillations
Chen, Songbai; Jing, Jiliang
2016-01-01
We extend firstly the regular phantom black hole solution to a slowly rotating black hole case and find that the phantom field depresses the angular velocity of the event horizon and suppresses the super-radiation of black hole. We also probe the dependence of quasi-periodic oscillations frequencies in relativistic precession model on the phantom parameter. With the observation data of GRO J1655-40, we make a constraint on the parameters of the regular and slowly rotating phantom black hole. Our results show that although the best-fit value of the phantom parameter $b$ is small, the allowed value of $b$ in the $1\\sigma$ region is $b<0.619$, which means that the phantom theoretical model can not be excluded by the constraint from quasi-periodic oscillations with the observation data of GRO J1655-40.
3D Relativistic MHD Simulation of a Tilted Accretion Disk Around a Rapidly Rotating Black Hole
Fragile, P Chris; Blaes, Omer M; Salmonson, Jay D
2016-01-01
We posit that accreting compact objects, including stellar mass black holes and neutron stars as well as supermassive black holes, may undergo extended periods of accretion during which the angular momentum of the disk at large scales is misaligned with that of the compact object. In such a scenario, Lense-Thirring precession caused by the rotating compact object can dramatically affect the disk. In this presentation we describe results from a three-dimensional relativistic magnetohydrodynamic simulation of an MRI turbulent disk accreting onto a tilted rapidly rotating black hole. For this case, the disk does not achieve the commonly described Bardeen-Petterson configuration; rather, it remains nearly planar, undergoing a slow global precession. Accretion from the disk onto the hole occurs predominantly through two opposing plunging streams that start from high latitudes with respect to both the black-hole and disk midplanes. This is a consequence of the non-sphericity of the gravitational spacetime of the bl...
Rotating black holes in a draining bathtub: superradiant scattering of gravity waves
Richartz, Mauricio; Liberati, Stefano; Weinfurtner, Silke
2014-01-01
In a draining rotating fluid flow background, surface perturbations behave as a scalar field on a rotating effective black hole spacetime. We propose a new model for the background flow which takes into account the varying depth of the water. Numerical integration of the associated Klein-Gordon equation using accessible experimental parameters shows that gravity waves in an appropriate frequency range are amplified through the mechanism of superradiance. Our numerical results suggest that the observation of this phenomenon in a common fluid mechanical system is within experimental reach. Unlike the case of wave scattering around Kerr black holes, which depends only on one dimensionless background parameter (the ratio $a/M$ between the specific angular momentum and the mass of the black hole), our system depends on two dimensionless background parameters, namely the normalized angular velocity and surface gravity at the effective black hole horizon.
Rotating black holes in a draining bathtub: Superradiant scattering of gravity waves
Richartz, Maurício; Prain, Angus; Liberati, Stefano; Weinfurtner, Silke
2015-06-01
In a draining rotating fluid flow background, surface perturbations behave as a scalar field on a rotating effective black hole spacetime. We propose a new model for the background flow which takes into account the varying depth of the water. Numerical integration of the associated Klein-Gordon equation using accessible experimental parameters shows that gravity waves in an appropriate frequency range are amplified through the mechanism of superradiance. Our numerical results suggest that the observation of this phenomenon in a common fluid mechanical system is within experimental reach. Unlike the case of wave scattering around Kerr black holes, which depends only on one dimensionless background parameter (the ratio a /M between the specific angular momentum and the mass of the black hole), our system depends on two dimensionless background parameters, namely the normalized angular velocity and surface gravity at the effective black hole horizon.
Testing gravity of a regular and slowly rotating phantom black hole by quasi-periodic oscillations
Chen, Songbai; Wang, Mei; Jing, Jiliang
2016-10-01
We extend firstly the regular phantom black hole solution to a slowly rotating black hole case and find that the phantom field depresses the angular velocity of the event horizon and suppresses the super-radiation of the black hole. We also probe the dependence of quasi-periodic oscillations frequencies in a relativistic precession model on the phantom parameter. With the observation data of GRO J1655-40, we make a constraint on the parameters of the regular and slowly rotating phantom black hole. Our results show that although the best-fit value of the phantom parameter b is small, the allowed value of b in the 1σ region is b\\lt 0.619, which means that the phantom theoretical model cannot be excluded by the constraint from quasi-periodic oscillations with the observation data of GRO J1655-40.
Effects of Rotation and Relativistic Charge Flow on Pulsar Magnetospheric Structure
Muslimov, A G; Muslimov, Alex G.; Harding, Alice K.
2005-01-01
We propose an analytical 3-D model of the open field-line region of a neutron star (NS) magnetosphere. We construct an explicit analytic solution for arbitrary obliquity (angle between the rotation and magnetic axes) incorporating the effects of magnetospheric rotation, relativistic flow of charges (e.g. primary electron beam) along the open field lines, and E X B drift of these charges. Our solution employs the space-charge-limited longitudinal current calculated in the electrodynamic model of Muslimov & Tsygan (1992) and is valid up to very high altitudes nearly approaching the light cylinder. We assume that in the innermost magnetosphere, the NS magnetic field can be well represented by a static magnetic dipole configuration. At high altitudes the open magnetic field lines significantly deviate from those of a static dipole and tend to focus into a cylindrical bundle, swept back in the direction opposite to the rotation, and also bent towards the rotational equator. We briefly discuss some implications...
The effects of black hole rotation on line profiles from accretion discs
Energy Technology Data Exchange (ETDEWEB)
Kojima, Yasufumi (Tokyo Metropolitan Univ. (Japan). Dept. of Physics)
1991-06-01
The fluorescent line emitted from an accretion disc around a rotating black hole is examined. The line profiles for various models with inclination angle, Kerr parameter and disc parameters are given. If the emitting region is highly localized to the inner part, r<20 GM/c{sup 2}, the difference due to the black hole rotation appears in the line profiles. Otherwise, the difference is hidden due to photons emitted from larger radii, where the propagation of the radiation and the disc structure are almost independent of the Kerr parameter. (author).
Chaotic motion of particles in the accelerating and rotating black holes spacetime
Chen, Songbai; Jing, Jiliang
2016-01-01
We have investigated the motion of timelike particles along geodesic in the background of accelerating and rotating black hole spacetime. We confirmed that the chaos exists in the geodesic motion of the particles by Poincar\\'e sections, the power spectrum, the fast Lyapunov exponent indicator and the bifurcation diagram. Moreover, we probe the effects of the acceleration and rotation parameters on the chaotic behavior of a timelike geodesic particle in the black hole spacetime. Our results show that the acceleration brings richer physics for the geodesic motion of particles.
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper,we extend fermions tunneling radiation to the case of five-dimensional charged black holes by introducing a set of appropriate matrices γμ for general covariant Dirac equation of 1/2 spin charged Dirac particles in the electromagnetic field.It is expected that our result can strengthen the validity and power of the tunneling method.We take the charged Gdel black holes in minimal five-dimensional gauged supergravity for example in order to present a reasonable extension of the tunneling method.As a result,we get fermions tunneling probability of the black hole and the Hawking temperature near the event horizon.
Phases of R-charged Black Holes, Spinning Branes and Strongly Coupled Gauge Theories
Cvetic, M; Cvetic, Mirjam; Gubser, Steven S.
1999-01-01
We study the thermodynamic stability of charged black holes in gauged supergravity theories in D=5, D=4 and D=7. We find explicitly the location of the Hawking-Page phase transition between charged black holes and the pure anti-de Sitter space-time, both in the grand-canonical ensemble, where electric potentials are held fixed, and in the canonical ensemble, where total charges are held fixed. We also find the explicit local thermodynamic stability constraints for black holes with one non-zero charge. In the grand-canonical ensemble, there is in general a region of phase space where neither the anti-de Sitter space-time is dynamically preferred, nor are the charged black holes thermodynamically stable. But in the canonical ensemble, anti-de Sitter space-time is always dynamically preferred in the domain where black holes are unstable. We demonstrate the equivalence of large R-charged black holes in D=5, D=4 and D=7 with spinning near-extreme D3-, M2- and M5-branes, respectively. The mass, the charges and the ...
Equatorial gravitational lensing by accelerating and rotating black hole with NUT parameter
Sharif, M.; Iftikhar, Sehrish
2016-01-01
This paper is devoted to study equatorial gravitational lensing in accelerating and rotating black hole with a NUT parameter in the strong field limit. For this purpose, we first calculate null geodesic equation using the Hamilton-Jacobi separation method. We then numerically obtain deflection angle and deflection coefficients which depend on acceleration and spin parameter of the black hole. We also investigate observables in the strong field limit by taking the example of a black hole in the center of galaxy. It is concluded that acceleration parameter has a significant effect on the strong field lensing in the equatorial plane.
Magnetic Coupling of a Rotating Black Hole with the SurroundingAccretion Disc
Institute of Scientific and Technical Information of China (English)
汪定雄; 肖看; 雷卫华
2001-01-01
The evolution characteristics and energy extraction of a rotating black hole are investigated by considering the magnetic coupling with the surrounding accretion disc. It is found that both the mass and spin of the black hole might be reduced by the joint effects of disc accretion and magnetic coupling, provided that the latter is stronger than the former. The efficiencies of the two energy mechanisms are calculated and compared to a variety of parameters. In addition, the validity of the laws of black hole thermodynamics is discussed.
A "horizon adapted" approach to the study of relativistic accretion flows onto rotating black holes
Font, J A; Papadopoulos, P P; Font, José A.; Ibanez, José M.; Papadopoulos, Philippos
1998-01-01
We present a new geometrical approach to the study of accretion flows onto rotating (Kerr) black holes. Instead of Boyer-Lindquist coordinates, the standard choice in all existing numerical simulations in the literature, we employ the simplest example of a horizon adapted coordinate system, the Kerr-Schild coordinates. This choice eliminates boundary ambiguities and unphysical divergent behavior at the event horizon. Computations of Bondi-Hoyle accretion onto extreme Kerr black holes, performed here for the first time, demonstrate the key advantages of this procedure. We argue it offers the best approach to the numerical study of the, observationally, increasingly more accesible relativistic inner region around black holes.
Instability of Charged Gauss-Bonnet Black Hole in de Sitter Spacetime at Large $D$
Chen, Bin
2016-01-01
We study the stabilities of (A)dS charged Gauss-Bonnet(GB) black holes in the large $D$ dimensions. After integrating the equation of motion with respect to the radial direction, we obtain the effective equations at large $D$ to describe the nonlinear dynamical deformations of the black hole. From the perturbation analysis of the effective equations, we get the analytic expressions of the frequencies for the quasinormal modes of scalar type. Furthermore we show that the charged GB black hole becomes unstable only if the cosmological constant is positive, otherwise the black hole is always stable. At the onset of instabilities there is a non-trivial static zero-mode perturbation, which suggests the existence of a new non-spherical symmetric solution branch of static dS charged GB black holes. We construct the non-spherical symmetric static solution of the large $D$ effective equations explicitly.
Nonlinear Evolution and Final Fate of Charged Anti-de Sitter Black Hole Superradiant Instability.
Bosch, Pablo; Green, Stephen R; Lehner, Luis
2016-04-08
We describe the full nonlinear development of the superradiant instability for a charged massless scalar field coupled to general relativity and electromagnetism, in the vicinity of a Reissner-Nordström-anti-de Sitter black hole. The presence of the negative cosmological constant provides a natural context for considering perfectly reflecting boundary conditions and studying the dynamics as the scalar field interacts repeatedly with the black hole. At early times, small superradiant perturbations grow as expected from linearized studies. Backreaction then causes the black hole to lose charge and mass until the perturbation becomes nonsuperradiant, with the final state described by a stable hairy black hole. For large gauge coupling, the instability extracts a large amount of charge per unit mass, resulting in greater entropy increase. We discuss the implications of the observed behavior for the general problem of superradiance in black hole spacetimes.
Charged Matter Tests of Cosmic Censorship for Extremal and Nearly-Extremal Black Holes
Sorce, Jonathan; Wald, Robert
2017-01-01
We investigate scenarios in which adding electrically charged matter to a black hole may cause it to become over-extremal, violating cosmic censorship. It has previously been shown that when the matter is localized as a point particle, no violation occurs for extremal black holes to lowest nonvanishing order in the particle's charge and mass. However, recent work has suggested that violations may be possible when the black hole deviates from extremality. We show that these potential violations always occur above lowest nonvanishing order, and conclude that no lowest-order violation can occur in the nearly-extremal case unless a violation also occurs in the extremal case. We also extend the previous results on point particles to show that no violations occur to second order in charge when an arbitrary charged matter configuration is added to an extremal Kerr black hole, provided only that the matter satisfies the null energy condition.
Conformally coupled scalar black holes admit a flat horizon due to axionic charge
Bardoux, Yannis; Charmousis, Christos
2012-01-01
Static, charged black holes in the presence of a negative cosmological constant and with a planar horizon are found in four dimensions. The solutions have scalar secondary hair. We claim that these constitute the planar version of the Martinez-Troncoso-Zanelli black holes, only known up to now for a curved event horizon in four dimensions. Their planar version is rendered possible due to the presence of two, equal and homogeneously distributed, axionic charges dressing the flat horizon. The solutions are presented in the conformal and minimal frame and their basic properties and thermodynamics analysed. Entertaining recent applications to holographic superconductors, we expose two branches of solutions: the undressed axionic Reissner-Nordstrom-AdS black hole, and the novel black hole carrying secondary hair. We show that there is a critical temperature at which the (bald) axionic Reissner-Nordstrom-AdS black hole undergoes a second order phase transition to the hairy black hole spontaneously acquiring scalar ...
Supersymmetric 4D rotating black holes from 5D black rings
Energy Technology Data Exchange (ETDEWEB)
Elvang, Henriette [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Emparan, Roberto [Institucio Catalana de Recerca i Estudis Avancats (ICREA) (Mexico); Departament de Fisica Fonamental, and C.E.R. en Astrofisica, Fisica de PartIcules i Cosmologia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Mateos, David [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Reall, Harvey S. [Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106-4030 (United States)
2005-08-01
We present supersymmetric solutions describing black holes with non-vanishing angular momentum in four dimensional asymptotically flat space. The solutions are obtained by Kaluza-Klein reduction of five-dimensional supersymmetric black rings wrapped on the fiber of a Taub-NUT space. We show that in the four-dimensional description the singularity of the nut can be hidden behind a regular black hole event horizon and thereby obtain an explicit example of a non-static multi-black hole solution in four asymptotically flat dimensions.
Black branes in AdS: BPS bounds and asymptotic charges
Energy Technology Data Exchange (ETDEWEB)
Hristov, K. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands); Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria); Toldo, C.; Vandoren, S. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)
2012-09-15
We focus on black branes and toroidal black holes in N = 2 gauged supergravities that asymptote to AdS{sub 4}, and derive formulas for the mass and central charge densities. We derive the corresponding BPS bound from the superalgebra of the asymptotic vacuum and illustrate our procedure with explicit examples of genuine black brane solutions with non-trivial scalars. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Charged BTZ black holes in the context of massive gravity's rainbow
Hendi, S H; Upadhyay, S; Panah, B Eslam
2016-01-01
Regarding the significant interests in thermodynamics of black objects, we examine charged BTZ black holes. We consider massive gravity context with an energy dependent spacetime to enrich the results. In addition, we consider all the constants as energy dependant ones. We investigate thermodynamic properties of the solutions by calculating the heat capacity and free energy. We also analyze thermal stability and study the possibility of Hawking-Page phase transition. At last, we study geometrical thermodynamics of these black holes.
Cotaescu, Ion I; Sporea, Ciprian
2016-01-01
The asymptotic form of the Dirac spinors in the field of the Reissner-Nordstrom black hole are derived for the scattering states (with $E>mc^2$) obtaining the phase shifts of the partial wave analysis of the Dirac fermions scattered from charged black holes. The elastic scattering and the absorption are studied giving analytic formulas for the partial amplitudes and cross sections.
Black Strings, Black Rings and State-space Manifold
Bellucci, Stefano
2011-01-01
State-space geometry is considered, for diverse three and four parameter non-spherical horizon rotating black brane configurations, in string theory and $M$-theory. We have explicitly examined the case of unit Kaluza-Klein momentum $D_1D_5P$ black strings, circular strings, small black rings and black supertubes. An investigation of the state-space pair correlation functions shows that there exist two classes of brane statistical configurations, {\\it viz.}, the first category divulges a degenerate intrinsic equilibrium basis, while the second yields a non-degenerate, curved, intrinsic Riemannian geometry. Specifically, the solutions with finitely many branes expose that the two charged rotating $D_1D_5$ black strings and three charged rotating small black rings consort real degenerate state-space manifolds. Interestingly, arbitrary valued $M_5$-dipole charged rotating circular strings and Maldacena Strominger Witten black rings exhibit non-degenerate, positively curved, comprehensively regular state-space con...
Thermodynamics of (2 +1 )-dimensional charged black holes with power-law Maxwell field
Dehghani, M.
2016-11-01
In this work, the three-dimensional nonlinearly charged black holes have been considered with a power-law modified electromagnetic theory. The black hole solutions to Einstein's three-dimensional field equations with a negative cosmological constant have been constructed in the presence of power-law nonlinear electrodynamics. Through the physical and mathematical interpretation of the solutions, a new class of asymptotically anti-de Sitter (AdS) black hole solutions has been introduced. The area law, surface gravity, and Gauss's law are utilized to obtain the entropy, temperature, and electric charge of the new AdS black holes, respectively. The quasilocal mass of the solutions has been calculated based on the counterterm method. A Smarr-type formula for the mass as a function of entropy and charge has been obtained. It has been shown that the thermodynamical quantities satisfy the first law of thermodynamics for the new AdS black holes. Also, it has been found that in order for the Smarr mass formula to be compatible with the first law of black hole thermodynamics, the cosmological parameter Λ should be treated as a thermodynamical variable and the generalized first law of thermodynamics has been introduced. Through the canonical ensemble method, the black hole remnant or phase transitions have been investigated regarding the black hole heat capacity. It has been found that the AdS black hole solutions we just obtained are thermodynamically stable.
Radiation spectrum of rotating Gdel black hole and correction entropy
Institute of Scientific and Technical Information of China (English)
张丽春; 林海; 李怀繁; 赵仁
2011-01-01
We study the Hawking radiation of the scalar field in the rotating Gdel black hole in minimal five-dimensional supergravity. We not only derive radiation spectra that satisfy the unitary principle but also obtain the correction term of Bekenstein-Hawking
Outgoing electromagnetic power induced from pair plasma falling into a rotating black hole
Kojima, Yasufumi
2015-01-01
We examine energy conversion from accreting pair plasma to outgoing Poynting flux by black hole rotation. Our approach is based on a two-fluid model consisting of collisionless pair plasma. The electric potential is not constant along magnetic field lines, unlike an ideal magnetohydrodynamics approximation. We show how and where longitudinal electric fields and toroidal magnetic fields are generated by the rotation, whereas they vanish everywhere for radial flow in a split monopole magnetic field in a Schwarzschild black hole. Outgoing electromagnetic power in a steady state is calculated by applying the WKB method to the perturbation equations for a small spin parameter. In our model, the luminosity has a peak in the vicinity of the black hole, but is damped toward the event horizon and infinity. The power at the peak is of the same order as that in the Blandford--Znajek process, although the physical mechanism is different.
Hawking fluxes and Anomalies in the Rotating Regular Black Holes with the Time-Delay
Takeuchi, Shingo
2016-01-01
We are going to calculate the flow of the angular momentum and flux of the Hawking radiation in the rotating regular black hole with the time-delay proposed in arXiv:1510.08828, based on the anomaly cancellation. We first try to reduce the field theories to the infinite two-dimensional massless free models in which the anomaly cancellation method is possible, in the three metrics in arXiv:1510.08828. We demonstrate that the two of them can be reduced. We perform the calculation in these two metrics, and obtain the flow of the angular momentum and flux of the Hawking radiation in these two metrics. Our result involves the three effects:~the quantum gravity effect regularizing the gravity sources of the black holes, the black hole rotation, and the time-delay. Hence our result could be considered to correspond to a more realistic Hawking radiations.
The formation of supermassive black holes in rapidly rotating disks
Latif, M. A.; Schleicher, D. R. G.
2015-06-01
Massive primordial halos exposed to moderate UV backgrounds are the potential birthplaces of supermassive black holes. In these halos, an initially isothermal collapse will occur, leading to high accretion rates of ~0.1 M⊙ yr-1. During the collapse, the gas in the interior will turn into a molecular state, and will form accretion disk in order to conserve angular momentum. We consider here the structure of such an accretion disk and the role of viscous heating in the presence of high accretion rates for a central star of 10, 100, and 104 M⊙. Our results show that the temperature in the disk increases considerably due to viscous heating, leading to a transition from the molecular to the atomic cooling phase. We found that the atomic cooling regime may extend out to several 100 AU for a 104 M⊙ central star and that it provides substantial support to stabilize the disk. It therefore favors the formation of a massive central object. The comparison of clump migration and contraction time scales shows that stellar feedback from these clumps may occur during the later stages of the evolution. Overall, viscous heating provides an important pathway to obtain an atomic gas phase within the center of the halo, and helps in the formation of very massive objects. The massive object may collapse to form a massive black hole of about ≥104 M⊙.
Sequences of extremal radially excited rotating black holes.
Blázquez-Salcedo, Jose Luis; Kunz, Jutta; Navarro-Lérida, Francisco; Radu, Eugen
2014-01-10
In the Einstein-Maxwell-Chern-Simons theory the extremal Reissner-Nordström solution is no longer the single extremal solution with vanishing angular momentum, when the Chern-Simons coupling constant reaches a critical value. Instead a whole sequence of rotating extremal J=0 solutions arises, labeled by the node number of the magnetic U(1) potential. Associated with the same near horizon solution, the mass of these radially excited extremal solutions converges to the mass of the extremal Reissner-Nordström solution. On the other hand, not all near horizon solutions are also realized as global solutions.
Renormalized vacuum polarization on rotating warped AdS3 black holes
Ferreira, Hugo R C
2014-01-01
We compute the renormalized vacuum polarization of a massive scalar field in the Hartle-Hawking state on (2+1)-dimensional rotating, spacelike stretched black hole solutions to Topologically Massive Gravity, surrounded by a Dirichlet mirror that makes the state well defined. The Feynman propagator is written as a mode sum on the complex Riemannian section of the spacetime, and a Hadamard renormalization procedure is implemented by matching to a mode sum on the complex Riemannian section of a rotating Minkowski spacetime. No analytic continuation in the angular momentum parameter is invoked. Selected numerical results are given, demonstrating the numerical efficacy of the method. We anticipate that this method can be extended to wider classes of rotating black hole spacetimes, in particular to the Kerr spacetime in four dimensions.
Renormalized vacuum polarization on rotating warped AdS3 black holes
Ferreira, Hugo R. C.; Louko, Jorma
2015-01-01
We compute the renormalized vacuum polarization of a massive scalar field in the Hartle-Hawking state on (2 +1 )-dimensional rotating, spacelike stretched black hole solutions to topologically massive gravity, surrounded by a Dirichlet mirror that makes the state well defined. The Feynman propagator is written as a mode sum on the complex Riemannian section of the spacetime, and a Hadamard renormalization procedure is implemented by matching to a mode sum on the complex Riemannian section of a rotating Minkowski spacetime. No analytic continuation in the angular momentum parameter is invoked. Selected numerical results are given, demonstrating the numerical efficacy of the method. We anticipate that this method can be extended to wider classes of rotating black hole spacetimes, in particular to the Kerr spacetime in four dimensions.
On the critical phenomena and thermodynamics of charged topological dilaton AdS black holes
Zhao, Ren; Ma, Meng-Sen; Zhang, Li-Chun
2013-01-01
In this paper, we study the phase structure and equilibrium state space geometry of charged topological dilaton black holes in $(n+1)$-dimensional anti-de Sitter spacetime. By considering the pairs of parameters $(P\\sim V)$ and $(Q\\sim U)$ as variables, we analyze the phase structure and critical phenomena of black holes and discuss the relation between the two kinds of critical phenomena. We find that the phase structures and critical phenomena drastically depend on the cosmological constant $l$ (or the static electric charge $Q$ of the black holes), dimensionality $n$ and dilaton field $\\Phi $.
Stringy stability of charged dilaton black holes with flat event horizon
Energy Technology Data Exchange (ETDEWEB)
Ong, Yen Chin [National Taiwan Univ., Taipei (Taiwan); Chen, Pisin [National Taiwan Univ., Taipei (Taiwan); SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-01-15
Electrically charged black holes with flat event horizon in anti-de Sitter space have received much attention due to various applications in Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, from modeling the behavior of quark-gluon plasma to superconductor. Critical to the physics on the dual field theory is the fact that when embedded in string theory, black holes in the bulk may become vulnerable to instability caused by brane pair-production. Since dilation arises naturally in the context of string theory, we study the effect of coupling dilation to Maxwell field on the stability of flat charged AdS black holes.
Excising a boosted rotating black hole with overlapping grids
Calabrese, G; Calabrese, Gioel; Neilsen, David
2004-01-01
We use the overlapping grids method to construct a fourth order accurate discretization of a first order reduction of the Klein-Gordon scalar field equation on a boosted spinning black hole blackground in axisymmetry. This method allows us to use a spherical outer boundary and excise the singularity from the domain with a spheroidal inner boundary which is moving with respect to the main grid. We discuss the use of higher order accurate energy conserving schemes to handle the axis of symmetry and compare it with a simpler technique based on regularity conditions. We also compare the single grid long term stability property of this formulation of the wave equation with that of a different first order reduction.
Stability of black holes in Einstein-charged scalar field theory in a cavity
Dolan, Sam R; Winstanley, Elizabeth
2015-01-01
Can a black hole that suffers a superradiant instability evolve towards a 'hairy' configuration which is stable? We address this question in the context of Einstein-charged scalar field theory. First, we describe a family of static black hole solutions which possess charged scalar-field hair confined within a mirror-like boundary. Next, we derive a set of equations which govern the linear, spherically symmetric perturbations of these hairy solutions. We present numerical evidence which suggests that, unlike the vacuum solutions, the (single-node) hairy solutions are stable under linear perturbations. Thus, it is plausible that stable hairy black holes represent the end-point of the superradiant instability of electrically-charged Reissner-Nordstrom black holes in a cavity; we outline ways to explore this hypothesis.
Thermodynamics of R-charged Black Holes in AdS(5) From Effective Strings
Gubser, S S; Gubser, Steven S.; Heckman, Jonathan J.
2004-01-01
It is well known that the thermodynamics of certain near-extremal black holes in asymptotically flat space can be lifted to an effective string description created from the intersection of D-branes. In this paper we present evidence that the semiclassical thermodynamics of near-extremal R-charged black holes in AdS(5)xS(5) is described in a similar manner by effective strings created from the intersection of giant gravitons on the S(5). We also present a free fermion description of the supersymmetric limit of the one-charge black hole, and we give a crude catalog of the microstates of the two and three-charge black holes in terms of operators in the dual conformal field theory.
Hairy black holes and the endpoint of AdS$_4$ charged superradiance
Dias, Oscar J C
2016-01-01
We construct hairy black hole solutions that merge with the anti-de Sitter (AdS$_4$) Reissner-Nordstr\\"om black hole at the onset of superradiance. These hairy black holes have, for a given mass and charge, higher entropy than the corresponding AdS$_4$-Reissner-Nordstr\\"om black hole. Therefore, they are natural candidates for the endpoint of the charged superradiant instability. On the other hand, hairy black holes never dominate the canonical and grand-canonical ensembles. The zero-horizon radius of the hairy black holes is a soliton (i.e. a boson star under a gauge transformation). We construct our solutions perturbatively, for small mass and charge, so that the properties of hairy black holes can be used to testify and compare with the endpoint of initial value simulations. We further discuss the near-horizon scalar condensation instability which is also present in global AdS$_4$-Reissner-Nordstr\\"om black holes. We highlight the different nature of the near-horizon and superradiant instabilities and that...
Pani, Paolo; Gualtieri, Leonardo
2013-01-01
In Einstein-Maxwell theory, according to classic uniqueness theorems, the most general stationary black-hole solution is the axisymmetric Kerr-Newman metric, which is defined by three parameters: mass, spin and electric charge. The radial and angular dependence of gravitational and electromagnetic perturbations in the Kerr-Newman geometry do not seem to be separable. In this paper we circumvent this problem by studying scalar, electromagnetic and gravitational perturbations of Kerr-Newman black holes in the slow-rotation limit. We extend (and provide details of) the analysis presented in a recent Letter [arXiv:1304.1160]. Working at linear order in the spin, we present the first detailed derivation of the axial and polar perturbation equations in the gravito-electromagnetic case, and we compute the corresponding quasinormal modes for any value of the electric charge. Our study is the first self-consistent stability analysis of the Kerr-Newman metric, and in principle it can be extended to any order in the sma...
P -V criticality of logarithm-corrected dyonic charged AdS black holes
Sadeghi, J.; Pourhassan, B.; Rostami, M.
2016-09-01
In this paper, we consider a dyonic charged anti-de Sitter black hole, which is a holographic dual of a van der Waals fluid. We use logarithm-corrected entropy and study thermodynamics of the black hole and show that holographic picture is still valid. Critical behaviors and stability are also discussed. Logarithmic corrections arises due to thermal fluctuations, which are important when the size of black hole is small. So, thermal fluctuations are interpreted as a quantum effect. It means that we can see the quantum effect of a black hole, which is a gravitational system.
Quantum electron levels in the field of a charged black hole
Energy Technology Data Exchange (ETDEWEB)
Dokuchaev, V. I.; Eroshenko, Yu. N., E-mail: eroshenko@ms2.inr.ac.ru [Institute for Nuclear Research of the Russian Academy of Sciences (Russian Federation)
2015-12-15
Stationary solutions of the Dirac equation in the metric of the charged Reissner–Nordstrom black hole are found. In the case of an extremal black hole, the normalization integral of the wave functions is finite, and the regular stationary solution is physically self-consistent. The presence of quantum electron levels under the Cauchy horizon can have an impact on the final stage of the Hawking evaporation of the black hole, as well as on the particle scattering in the field of the black hole.
Schwinger Effect in (A)dS and Charged Black Hole
Kim, Sang Pyo
2015-01-01
In an (Anti-) de Sitter space and a charged black hole the Schwinger effect is either enhanced by the Hawking radiation or suppressed by the negative curvature. We use the contour integral method to calculate the production of charged pairs in the global (A)dS space. The charge emission from near-extremal black hole is found from the AdS geometry near the horizon and interpreted as the Schwinger effect in a Rindler space with the surface gravity for the acceleration as well as the Schwinger effect in AdS space.
Charged Black Hole Solutions in Gauss-Bonnet-Massive Gravity
Hendi, S H; Panah, B Eslam
2015-01-01
Motivated by high interest in the close relation between string theory and black hole solutions, in this paper, we take into account the Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity. We examine the possibility of black hole in this regard, and discuss the types of horizons. Next, we calculate conserved and thermodynamic quantities and check the validity of the first law of thermodynamics. In addition, we investigate the stability of these black holes in context of canonical ensemble. We show that number, type and place of phase transitions points may be significantly affected by the different parameters. Next, by considering cosmological constant as thermodynamical pressure, we will extend phase space and calculate critical values. Then, we construct thermodynamical spacetime by considering mass as thermodynamical potential. We study geometrical thermodynamics of these black holes in context of heat capacity and extended phase space. We show that studying heat capacity, geometrical therm...
Powerful, Rotating Disk Winds from Stellar-mass Black Holes
Miller, J M; Kaastra, J; Kallman, T; King, A L; Proga, D; Raymond, J; Reynolds, C S
2015-01-01
We present an analysis of ionized X-ray disk winds observed in the Fe K band of four stellar-mass black holes observed with Chandra, including 4U 1630-47, GRO J1655-40, H 1743-322, and GRS 1915+105. High-resolution photoionization grids were generated in order to model the data. Third-order gratings spectra were used to resolve complex absorption profiles into atomic effects and multiple velocity components. The Fe XXV line is found to be shaped by contributions from the intercombination line (in absorption), and the Fe XXVI line is detected as a spin-orbit doublet. The data require 2-3 absorption zones, depending on the source. The fastest components have velocities approaching or exceeding 0.01c, increasing mass outflow rates and wind kinetic power by orders of magnitude over prior single-zone models. The first-order spectra require re-emission from the wind, broadened by a degree that is loosely consistent with Keplerian orbital velocities at the photoionization radius. This suggests that disk winds are ro...
The Force-Free Magnetosphere of a Rotating Black Hole
Contopoulos, Ioannis; Kazanas, Demosthenes; Papadopoulos, Demetrios B.
2013-01-01
We revisit the Blandford-Znajek process and solve the fundamental equation that governs the structure of the steady-state force-free magnetosphere around a Kerr black hole. The solution depends on the distributions of the magnetic field angular velocity and the poloidal electric current. These are not arbitrary. They are determined self-consistently by requiring that magnetic field lines cross smoothly the two singular surfaces of the problem: the inner "light surface" located inside the ergosphere and the outer "light surface" which is the generalization of the pulsar light cylinder.We find the solution for the simplest possible magnetic field configuration, the split monopole, through a numerical iterative relaxation method analogous to the one that yields the structure of the steady-state axisymmetric force-free pulsar magnetosphere. We obtain the rate of electromagnetic extraction of energy and confirm the results of Blandford and Znajek and of previous time-dependent simulations. Furthermore, we discuss the physical applicability of magnetic field configurations that do not cross both "light surfaces."
Nernst Theorem and Statistical Entropy of 5-Dimensional Rotating Black Hole
Institute of Scientific and Technical Information of China (English)
ZHAORen; WUYue-Qin; ZHANGLi-Chun
2003-01-01
In this paper, by using quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of the 5-dimensional rotating black hole. Then via the improved brick-wall method and membrane model, we calculate the entropy of Bose field and Fermi field of the black hole. And it is obtained that the entropy of the black hole is not only related to the area of the outer horizon but also is the function of inner horizon's area. In our results, there are not the left out term and the divergent logarithmic term in the original brick-wall method.The doubt that why the entropy of the scalar or Dirac field outside the event horizon is the entropy of the black hole in the original brick-wall method does not exist. The influence of spinning degeneracy of particles on entropy of the black hole is also given. It is shown that the entropy determined by the areas of the inner and outer horizons will approach zero,when the radiation temperature of the black hole approaches absolute zero. It satisfies Nernst theorem. The entropy can be taken as the Planck absolute entropy. We provide a way to study higher dimensional black hole.
Harrison transformation and charged black objects in Kaluza-Klein theory
Kleihaus, Burkhard; Radu, Eugen; Stelea, Cristian
2009-01-01
We generate charged black brane solutions in $D-$dimensions in a theory of gravity coupled to a dilaton and an antisymmetric form, by using a Harrison-type transformation. The seed vacuum solutions that we use correspond to uplifted Kaluza-Klein black strings and black holes in $(D-p)$-dimensions. A generalization of the Marolf-Mann quasilocal formalism to the Kaluza-Klein theory is also presented, the global charges of the black objects being computed in this way. We argue that the thermodynamics of the charged solutions can be derived from that of the vacuum configurations. Our results show that all charged Kaluza-Klein solutions constructed by means of Harrison transformations are thermodynamically unstable in a grand canonical ensemble. The general formalism is applied to the case of nonuniform black strings and caged black hole solutions in $D=5, 6$ Einstein-Maxwell-dilaton gravity, whose geometrical properties and thermodynamics are discussed. We argue that the topology changing transition scenario, whi...
Regular black holes: Electrically charged solutions, Reissner-Nordstr\\"om outside a de Sitter core
Lemos, José P S
2011-01-01
To have the correct picture of a black hole as a whole it is of crucial importance to understand its interior. The singularities that lurk inside the horizon of the usual Kerr-Newman family of black hole solutions signal an endpoint to the physical laws and as such should be substituted in one way or another. A proposal that has been around for sometime, is to replace the singular region of the spacetime by a region containing some form of matter or false vacuum configuration that can also cohabit with the black hole interior. Black holes without singularities are called regular black holes. In the present work regular black hole solutions are found within general relativity coupled to Maxwell's electromagnetism and charged matter. We show that there are objects which correspond to regular charged black holes, whose interior region is de Sitter, whose exterior region is Reissner-Nordstr\\"om, and the boundary between both regions is made of an electrically charged spherically symmetric coat. There are several ...
Energy Technology Data Exchange (ETDEWEB)
Rahaman, Farook; Bhar, Piyali [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Sharma, Ranjan [P. D. Women' s College, Department of Physics, Jalpaiguri (India); Tiwari, Rishi Kumar [Govt. Model Science College, Department of Mathematics, Rewa, MP (India)
2015-03-01
We report a 3-D charged black hole solution in an anti-de Sitter space inspired by noncommutative geometry. In this construction, the black hole exhibits two horizons, which turn into a single horizon in the extreme case. We investigate the impacts of electromagnetic field on the location of the event horizon, mass and thermodynamic properties such as Hawking temperature, entropy, and heat capacity of the black hole. The geodesics of the charged black hole are also analyzed. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Stuchlik, Zdenek; Kolos, Martin [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Opava (Czech Republic)
2016-01-15
To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)
Prasia, P
2016-01-01
In this work we study the Quasi Normal Modes(QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter((A)dS) space time. It is found that the behavior of QNMs changes with the massive parameter and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter and also on the charge of the black hole.
Time domain analysis of superradiant instability for the charged stringy black hole–mirror system
Directory of Open Access Journals (Sweden)
Ran Li
2015-11-01
Full Text Available It has been proved that the charged stringy black holes are stable under the perturbations of massive charged scalar fields. However, superradiant instability can be generated by adding the mirror-like boundary condition to the composed system of charged stringy black hole and scalar field. The unstable boxed quasinormal modes have been calculated by using both analytical and numerical methods. In this paper, we further provide a time domain analysis by performing a long time evolution of charged scalar field configuration in the background of the charged stringy black hole with the mirror-like boundary condition imposed. We have used the ingoing Eddington–Finkelstein coordinates to derive the evolution equation, and adopted Pseudo-spectral method and the forth-order Runge–Kutta method to evolve the scalar field with the initial Gaussian wave packet. It is shown by our numerical scheme that Fourier transforming the evolution data coincides well with the unstable modes computed from frequency domain analysis. The existence of the rapid growth mode makes the charged stringy black hole a good test ground to study the nonlinear development of superradiant instability.
Time domain analysis of superradiant instability for the charged stringy black hole-mirror system
Li, Ran; Tian, Yu; Zhang, Hongbao; Zhao, Junkun
2015-11-01
It has been proved that the charged stringy black holes are stable under the perturbations of massive charged scalar fields. However, superradiant instability can be generated by adding the mirror-like boundary condition to the composed system of charged stringy black hole and scalar field. The unstable boxed quasinormal modes have been calculated by using both analytical and numerical methods. In this paper, we further provide a time domain analysis by performing a long time evolution of charged scalar field configuration in the background of the charged stringy black hole with the mirror-like boundary condition imposed. We have used the ingoing Eddington-Finkelstein coordinates to derive the evolution equation, and adopted Pseudo-spectral method and the forth-order Runge-Kutta method to evolve the scalar field with the initial Gaussian wave packet. It is shown by our numerical scheme that Fourier transforming the evolution data coincides well with the unstable modes computed from frequency domain analysis. The existence of the rapid growth mode makes the charged stringy black hole a good test ground to study the nonlinear development of superradiant instability.
Gravitational perturbation induced by a rotating ring around a Kerr black hole
Sano, Yasumichi
2014-01-01
The linear perturbation of a Kerr black hole induced by a rotating massive circular ring is discussed by using the formalism by Teukolsky, Chrzanowski, Cohen and Kegeles. In these formalism, the perturbed Weyl scalars, $\\psi_0$ and $\\psi_4$, are first obtained from the Teukolsky equation. The perturbed metric is obtained in a radiation gauge via the Hertz potential. The computation can be done in the same way as in our previous paper, in which we considered the perturbation of a Schwarzschild black hole induced by a rotating ring. By adding lower multipole modes such as mass and angular momentum perturbation which are not computed by the Teukolsky equation, and by appropriately setting the parameters which are related to the gauge freedom, we obtain the perturbed gravitational field which is smooth except on the equatorial plane outside the ring.
Thermodynamics of rotating black branes in gravity with first order string corrections
Directory of Open Access Journals (Sweden)
M. H. Dehghani
2005-09-01
Full Text Available In this paper, the rotating black brane solutions with zero curvature horizon of classical gravity with first order string corrections are introduced. Although these solutions are not asymptotically anti de Sitter, one can use the counterterm method in order to compute the conserved quantities of these solutions. Here, by reviewing the counterterm method for asymptotically anti de Sitter spacetimes, the conserved quantities of these rotating solutions are computed. Also a Smarr-type formula for the mass as a function of the entropy and the angular momenta is obtained, and it is shown that the conserved and thermodynamic quantities satisfy the first law of thermodynamics. Finally, a stability analysis in the canonical ensemble is performed, and it is shown that the system is thermally stable. This is in commensurable with the fact that there is no Hawking-Page phase transition for black object with zero curvature horizon.
Charged black hole solutions in Gauss-Bonnet-massive gravity
Hendi, S. H.; Panahiyan, S.; Panah, B. Eslam
2016-01-01
Motivated by high interest in the close relation between string theory and black hole solutions, in this paper, we take into account the Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity. We examine the possibility of black hole in this regard, and discuss the types of horizons. Next, we calculate conserved and thermodynamic quantities and check the validity of the first law of thermodynamics. In addition, we investigate the stability of these black holes in context of canonical ensemble. We show that number, type and place of phase transition points may be significantly affected by different parameters. Next, by considering cosmological constant as thermodynamical pressure, we will extend phase space and calculate critical values. Then, we construct thermodynamical spacetime by considering mass as thermodynamical potential. We study geometrical thermodynamics of these black holes in context of heat capacity and extended phase space. We show that studying heat capacity, geometrical thermodynamics and critical behavior in extended phase space lead to consistent results. Finally, we will employ a new method for obtaining critical values and show that the results of this method are consistent with those of other methods.
Chaotic dynamics of strings in charged black hole backgrounds
Basu, Pallab; Samantray, Prasant
2016-01-01
We study the motion of a string in the background of Reissner-Nordstrom black hole, in both AdS as well as asymptotically flat spacetimes. We describe the phase space of this dynamical system through largest Lyapunov exponent, Poincare sections and basins of attractions. We observe that string motion in these settings is particularly chaotic and comment on its characteristics.
Critical Phenomena in Higher Curvature Charged AdS Black Holes
Directory of Open Access Journals (Sweden)
Arindam Lala
2013-01-01
Full Text Available In this paper, we have studied the critical phenomena in higher curvature charged AdS black holes. We have considered Lovelock-Born-Infeld-AdS black hole as an example. The thermodynamics of the black hole have been studied which reveals the onset of a higher-order phase transition in the black hole in the canonical ensemble (fixed charge ensemble framework. We have analytically derived the critical exponents associated with these thermodynamic quantities. We find that our results fit well with the thermodynamic scaling laws and consistent with the mean field theory approximation. The suggestive values of the other two critical exponents associated with the correlation function and correlation length on the critical surface have been derived.
Magnetically charged regular black hole in a model of nonlinear electrodynamics
Ma, Meng-Sen
2015-01-01
We obtain a magnetically charged regular black hole in general relativity. The source to the Einstein field equations is nonlinear electrodynamic field in a physically reasonable model of nonlinear electrodynamics (NED). "Physically" here means the NED model is constructed on the basis of three conditions: the Maxwell asymptotic in the weak electromagnetic field limit; the presence of vacuum birefringence phenomenon; and satisfying the weak energy condition (WEC). In addition, we analyze the thermodynamic properties of the regular black hole in two ways. According to the usual black hole thermodynamics, we calculate the heat capacity at constant charge, from which we know the smaller black hole is more stable. We also employ the horizon thermodynamics to discuss the thermodynamic quantities, especially the heat capacity at constant pressure.
Hawking Radiation of Spin-1 Particles From Three Dimensional Rotating Hairy Black Hole
Sakalli, I
2015-01-01
In the present article, we study the Hawking radiation (HR) of spin-1 particles -- so-called vector particles -- from a three dimensional (3D) rotating black hole with scalar hair (RBHWSH) using Hamilton-Jacobi (HJ) ansatz. Putting the Proca equation amalgamated with the WKB approximation in process, the tunneling spectrum of vector particles is obtained. We recover the standard Hawking temperature corresponding to the emission of these particles from RBHWSH.
Analytic solutions of the geodesic equation for U(1)^2 dyonic rotating black holes
Flathmann, Kai
2016-01-01
In this article we derive the geodesic equations in the $\\text{U(1)}^2$ dyonic rotating black hole spacetime. We present their solutions in terms of the Kleinian $\\sigma$-function and in special cases in terms of the Weierstra{\\ss} $\\wp$-, $\\sigma$- and $\\zeta$-functions. To give a list of all possible orbits, we analyse the geodesic motion of test particles and light using parametric diagrams and effective potentials.
QPOs from Random X-ray Bursts around Rotating Black Holes
Kukumura, Keigo; Kazanas, Demosthenes; Stephenson, Gordon
2009-01-01
We continue our earlier studies of quasi-periodic oscillations (QPOs) in the power spectra of accreting, rapidly-rotating black holes that originate from the geometric 'light echoes' of X-ray flares occurring within the black hole ergosphere. Our present work extends our previous treatment to three-dimensional photon emission and orbits to allow for arbitrary latitudes in the positions of the distant observers and the X-ray sources in place of the mainly equatorial positions and photon orbits of the earlier consideration. Following the trajectories of a large number of photons we calculate the response functions of a given geometry and use them to produce model light curves which we subsequently analyze to compute their power spectra and autocorrelation functions. In the case of an optically-thin environment, relevant to advection-dominated accretion flows, we consistently find QPOs at frequencies of order of approximately kHz for stellar-mass black hole candidates while order of approximately mHz for typical active galactic nuclei (approximately equal to 10(exp 7) solar mass) for a wide range of viewing angles (30 degrees to 80 degrees) from X-ray sources predominantly concentrated toward the equator within the ergosphere. As in out previous treatment, here too, the QPO signal is produced by the frame-dragging of the photons by the rapidly-rotating black hole, which results in photon 'bunches' separated by constant time-lags, the result of multiple photon orbits around the hole. Our model predicts for various source/observer configurations the robust presence of a new class of QPOs, which is inevitably generic to curved spacetime structure in rotating black hole systems.
(Anti-) de Sitter Electrically Charged Black Hole Solutions in Higher-Derivative Gravity
Lin, Kai; Pavan, A B; Abdalla, E
2016-01-01
In this paper, static electrically charged black hole solutions with cosmological constant are investigated in an Einstein-Hilbert theory of gravity with additional quadratic curvature terms. Beside the analytic Schwarzschild (Anti-) de Sitter solutions, non-Schwarzschild (Anti-) de Sitter solutions are also obtained numerically by employing the shooting method. The results show that there exist two groups of asymptotically (Anti-) de Sitter spacetimes for both charged and uncharged black holes. In particular, it was found that for uncharged black holes the first group can be reduced to the Schwarzschild (Anti-) de Sitter solution, while the second group is intrinsically different from a Schwarzschild (Anti-) de Sitter solution even when the charge and the cosmological constant become zero.
Tunnelling Radiation of Charged and Magnetized Massive Particles from BTZ Black Holes
Institute of Scientific and Technical Information of China (English)
HE Tang-Mei; ZHANG Jing-Yi
2007-01-01
We investigate the tunnelling radiation of charged and magnetized massive particles from a Ba(n)ados-TeitelboimZanelli (BTZ) black hole by extending the Parikh-Wilczek tunnelling framework. In order to calculate the emission rate,we reconstruct the electromagnetic field tensor and the Lagrangian of the field corresponding to the source with electric and magnetic charges,and treat the charges as an equivalent electric charge for simplicity in the later calculation.The result supports Parikh-Wilczek's conclusion,that is,the Hawking thermal radiation actually deviates from perfect thermality and agrees with an underlying unitary theory.
Hawking radiation from the charged and magnetized BTZ black hole via covariant anomaly
Institute of Scientific and Technical Information of China (English)
Zeng Xiao-Xiong; Yang Shu-Zheng
2009-01-01
This paper discusses Hawking radiation from the charged and magnetized Bafiados-Teitelboim-Zanelli (BTZ) black hole from the viewpoint of anomaly, initiated by Robinson and Wilczek recently. It reconstructs the electromagnetic field tensor and the Lagrangian of the field corresponding to the source with electric and magnetic charges to redefine an equivalent charge and gauge potential. It employs the covariant anomaly cancellation method to determine thecompensating fluxes of charge flow and energy-momentum tensor, which are shown to match with those of the 2- dimensional blackbody radiation at the Hawking temperature exactly.
Shaymatov, Sanjar; Ahmedov, Bobomurat; Joshi, Pankaj S
2014-01-01
We investigate effect of a test magnetic field on the process of destroying near-extremal Kerr black hole with a charged test particle. It has been shown that it would be possible to throw a charged test particle into the near extremal rotating black hole and make it go past the extremality i.e. turn Kerr black hole into the Kerr-Newmann naked singularity. Typically in an astrophysical scenario black holes are believed to be surrounded by a magnetic field. Magnetic field although small, affects motion of charged particles drastically due to the large Lorentz force, as the electromagnetic force is much stronger that the gravity. Thus a test magnetic field can affect the process of destroying black holes and restore the cosmic censorship in the astrophysical context. We show that a test magnetic field would act as a cosmic censor beyond a certain threshold value. We try to gauge the magnitude of the magnetic field by comparing its energy density with that of the change in the curvature induced by the test parti...
Azreg-Aïnou, Mustapha
2012-01-01
Properties pertaining to thermodynamical local stability of Reissner-Nordstr\\"om black holes surrounded by quintessence as well as adiabatic invariance, adiabatic charging and a generalized Smarr formula are discussed. Limits for the entropy, temperature and electric potential ensuring stability of canonical ensembles are determined by the classical thermodynamical and Poincar\\'e methods. By the latter approach we show that microcanonical ensembles (isolated black holes) are stable. Two geometrical approaches lead to determine the same states corresponding to second order phase transitions.
Effect of scalar field mass on gravitating charged scalar solitons and black holes in a cavity
Ponglertsakul, Supakchai
2016-01-01
We study soliton and black hole solutions of Einstein charged scalar field theory in cavity. We examine the effect of introducing a scalar field mass on static, spherically symmetric solutions of the field equations. We focus particularly on the spaces of soliton and black hole solutions, as well as studying their stability under linear, spherically symmetric perturbations of the metric, electromagnetic field, and scalar field.
Effect of scalar field mass on gravitating charged scalar solitons and black holes in a cavity
Ponglertsakul, Supakchai; Winstanley, Elizabeth
2017-01-01
We study soliton and black hole solutions of Einstein charged scalar field theory in cavity. We examine the effect of introducing a scalar field mass on static, spherically symmetric solutions of the field equations. We focus particularly on the spaces of soliton and black hole solutions, as well as studying their stability under linear, spherically symmetric perturbations of the metric, electromagnetic field, and scalar field.
Hawking fluxes and anomalies in rotating regular black holes with a time-delay
Takeuchi, Shingo
2016-11-01
Based on the anomaly cancellation method we compute the Hawking fluxes (the Hawking thermal flux and the total flux of energy-momentum tensor) from a four-dimensional rotating regular black hole with a time-delay. To this purpose, in the three metrics proposed in [1], we try to perform the dimensional reduction in which the anomaly cancellation method is feasible at the near-horizon region in a general scalar field theory. As a result we can demonstrate that the dimensional reduction is possible in two of those metrics. Hence we perform the anomaly cancellation method and compute the Hawking fluxes in those two metrics. Our Hawking fluxes involve three effects: (1) quantum gravity effect regularizing the core of the black holes, (2) rotation of the black hole, (3) time-delay. Further in this paper toward the metric in which the dimensional could not be performed, we argue that it would be some problematic metric, and mention its cause. The Hawking fluxes we compute in this study could be considered to correspond to more realistic Hawking fluxes. Further what Hawking fluxes can be obtained from the anomaly cancellation method would be interesting in terms of the relation between a consistency of quantum field theories and black hole thermodynamics.
Three-dimensional SCFT on conic space as hologram of charged topological black hole
Energy Technology Data Exchange (ETDEWEB)
Huang, Xing [School of Physics & Astronomy and Center for Theoretical Physics,Seoul National University, Seoul 151-747 (Korea, Republic of); Rey, Soo-Jong [School of Physics & Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); Center for Quantum Space-Time, Sogang University,Seoul 121-742 (Korea, Republic of); Zhou, Yang [Center for Quantum Space-Time, Sogang University, Seoul 121-742 (Korea, Republic of)
2014-03-26
We construct three-dimensional N=2 supersymmetric field theories on conic spaces. Built upon the fact that the partition function depends solely on the Reeb vector of the Killing vector, we propose that holographic dual of these theories are four-dimensional, supersymmetric charged topological black holes. With the supersymmetry localization technique, we study conserved supercharges, free energy, and supersymmetric Rényi entropy. At planar large N limit, we demonstrate perfect agreement between the superconformal field theories and the supersymmetric charged topological black holes.
Huang, Xing; Zhou, Yang
2014-01-01
We construct three-dimensional N=2 supersymmetric conformal field theories on conic spaces. Built upon the fact that the partition function depends solely on the Reeb vector of the Killing vector, we propose that holographic dual of these theories are four-dimensional, supersymmetric charged topological black holes. With the supersymmetry localization technique, we study conserved supercharges, free energy, and Renyi entropy. At planar large N limit, we demonstrate perfect agreement between the superconformal field theories and the supersymmetric charged topological black holes.
A perspective on Black Hole Horizons from the Quantum Charged Particle
Jaramillo, José Luis
2016-01-01
Black hole apparent horizons possess a natural notion of stability, whose spectral characterization can be related to the problem of the stationary quantum charged particle. Such mathematical relation leads to an "analyticity conjecture" on the dependence of the spectral properties on a complex "fine-structure-constant" parameter, that can reduce the study of the spectrum of the (non-selfadjoint) MOTS-stability operator to that of the (selfadjoint) Hamiltonian of the quantum charged particle. Moreover, this perspective might open an avenue to the spinorial treatment of apparent horizon (MOTS-)stability and to the introduction of semiclassical tools to explore some of the qualitative aspects of this black hole spectral problem.
Tunneling of massive and charged particles from noncommutative Reissner-Nordstr\\"{o}m black hole
Nozari, Kourosh
2012-01-01
Massive charged and uncharged particles tunneling from commutative Reissner-Nordstrom black hole horizon has been studied with details in literature. Here, by adopting the coherent state picture of spacetime noncommutativity, we study tunneling of massive and charged particles from a noncommutative inspired Reissner-Nordstrom black hole horizon. We show that Hawking radiation in this case is not purely thermal and there are correlations between emitted modes. These correlations may provide a solution to the information loss problem. We also study thermodynamics of noncommutative horizon in this setup.
Institute of Scientific and Technical Information of China (English)
YANG Shu-Zheng; CHEN De-You
2007-01-01
@@ Taking the self-gravitation interaction and energy conservation, charge conservation and angular momentum conservation into account, we discuss the tunnelling characteristics of the charged particle from Sen black hole by the Hamilton-Jacobi method. The result shows that the tunnelling probability is related to the change of Bekenstein-Hawking entropy, and the actual radiation spectrum deviates from the pure thermal one, which is consistent with the result of Parikh and Wilczek and gives a new method to correct the Hawking pure thermal spectrum of Sen black hole.
Chaotic dynamics of strings in charged black hole backgrounds
Basu, Pallab; Chaturvedi, Pankaj; Samantray, Prasant
2017-03-01
We study the motion of a string in the background of a Reissner-Nordstrom black hole, in both anti-de Sitter as well as asymptotically flat spacetimes. We describe the phase space of this dynamical system through the largest Lyapunov exponent, Poincaré sections and basins of attraction. We observe that string motion in these settings is particularly chaotic and comment on its characteristics.
Total Energy of Charged Black Holes in Einstein-Maxwell-Dilaton-Axion Theory
Directory of Open Access Journals (Sweden)
Murat Korunur
2012-01-01
Full Text Available We focus on the energy content (including matter and fields of the Møller energy-momentum complex in the framework of Einstein-Maxwell-Dilaton-Axion (EMDA theory using teleparallel gravity. We perform the required calculations for some specific charged black hole models, and we find that total energy distributions associated with asymptotically flat black holes are proportional to the gravitational mass. On the other hand, we see that the energy of the asymptotically nonflat black holes diverge in a limiting case.
Black locust (Robinia pseudoacacia L. Short-Rotation Crops under Marginal Site Conditions
Directory of Open Access Journals (Sweden)
RÉDEI, Károly
2011-01-01
Full Text Available The improvement of the reliability of renewable resources and the decline in reserves offossile raw material in the coming decades will lead to increasing demands for wood material andconsequently to a greater role of short rotation forestry (SRF. Particular efforts have been made inEurope to substitute fossils with renewables, in this context the proportion of renewable energy shouldbe increased to 20% by 2020. SRF can be provide relatively high dendromass (biomass incrementrates if the short rotation tree plantations are grown under favourable site conditions and for anoptimum rotation length. However, in many countries only so-called marginal sites are available forsetting up tree plantations for energy purpose. For SRF under marginal site conditions black locust(Robinia pseudoacacia L. can be considered as one of the most promising tree species thanks to itsfavourable growing characteristics. According to a case study presented in the paper black locust canproduce a Mean Annual Increment (MAI of 2.9 to 9.7 oven-dry tons ha–1 yr–1 at ages between 3 and7 years using a stocking density of 6667 stems ha–1. On the base of the presented results and accordingto international literature the expected dendromass volume shows great variation, depending upon site,species, their cultivars, initial spacing and length of rotation cycle.
Charged isotropic non-Abelian dyonic black branes
Directory of Open Access Journals (Sweden)
Yves Brihaye
2015-05-01
Full Text Available We construct black holes with a Ricci-flat horizon in Einstein–Yang–Mills theory with a negative cosmological constant, which approach asymptotically an AdSd spacetime background (with d≥4. These solutions are isotropic, i.e. all space directions in a hypersurface of constant radial and time coordinates are equivalent, and possess both electric and magnetic fields. We find that the basic properties of the non-Abelian solutions are similar to those of the dyonic isotropic branes in Einstein–Maxwell theory (which, however, exist in even spacetime dimensions only. These black branes possess a nonzero magnetic field strength on the flat boundary metric, which leads to a divergent mass of these solutions, as defined in the usual way. However, a different picture is found for odd spacetime dimensions, where a non-Abelian Chern–Simons term can be incorporated in the action. This allows for black brane solutions with a magnetic field which vanishes asymptotically.
The charged black-hole bomb: A lower bound on the charge-to-mass ratio of the explosive scalar field
Directory of Open Access Journals (Sweden)
Shahar Hod
2016-04-01
Full Text Available The well-known superradiant amplification mechanism allows a charged scalar field of proper mass μ and electric charge q to extract the Coulomb energy of a charged Reissner–Nordström black hole. The rate of energy extraction can grow exponentially in time if the system is placed inside a reflecting cavity which prevents the charged scalar field from escaping to infinity. This composed black-hole-charged-scalar-field-mirror system is known as the charged black-hole bomb. Previous numerical studies of this composed physical system have shown that, in the linearized regime, the inequality q/μ>1 provides a necessary condition for the development of the superradiant instability. In the present paper we use analytical techniques to study the instability properties of the charged black-hole bomb in the regime of linearized scalar fields. In particular, we prove that the lower bound qμ>rm/r−−1rm/r+−1 provides a necessary condition for the development of the superradiant instability in this composed physical system (here r± are the horizon radii of the charged Reissner–Nordström black hole and rm is the radius of the confining mirror. This analytically derived lower bound on the superradiant instability regime of the composed black-hole-charged-scalar-field-mirror system is shown to agree with direct numerical computations of the instability spectrum.
A rotating hairy AdS$_3$ black hole with the metric having only one Killing vector field
Iizuka, Norihiro; Maeda, Kengo
2015-01-01
We perturbatively construct a three-dimensional rotating AdS black hole with a real scalar hair. We choose the mass of a scalar field slightly above the Breitenlohner-Freedman bound and impose a more general boundary condition for the bulk scalar field at AdS infinity. We first show that rotating BTZ black holes are unstable against superradiant modes under our more general boundary condition. Next we construct a rotating hairy black hole perturbatively with respect to a small amplitude $\\epsilon$ of the scalar field, up to $O(\\epsilon^4)$. The lumps of non-linearly perturbed geometry admit only one Killing vector field and co-rotate with the black hole, and it shows no dissipation. We numerically show that the entropy of our hairy black hole is larger than that of the BTZ black hole with the same energy and the angular momentum. This indicates, at least in the perturbative level, that our rotating hairy black hole in lumpy geometry can be the endpoint of the superradiant instability.
Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo
2013-06-14
The most general stationary black-hole solution of Einstein-Maxwell theory in vacuum is the Kerr-Newman metric, specified by three parameters: mass M, spin J, and charge Q. Within classical general relativity, one of the most important and challenging open problems in black-hole perturbation theory is the study of gravitational and electromagnetic fields in the Kerr-Newman geometry, because of the indissoluble coupling of the perturbation functions. Here we circumvent this long-standing problem by working in the slow-rotation limit. We compute the quasinormal modes up to linear order in J for any value of Q and provide the first, fully consistent stability analysis of the Kerr-Newman metric. For scalar perturbations the quasinormal modes can be computed exactly, and we demonstrate that the method is accurate within 3% for spins J/J(max) ≲ 0.5, where J(max) is the maximum allowed spin for any value of Q. Quite remarkably, we find numerical evidence that the axial and polar sectors of the gravitoelectromagnetic perturbations are isospectral to linear order in the spin. The extension of our results to nonasymptotically flat space-times could be useful in the context of gauge-gravity dualities and string theory.
Pani, Paolo; Gualtieri, Leonardo
2013-01-01
The most general stationary black-hole solution of Einstein-Maxwell theory in vacuum is the Kerr-Newman metric, specified by three parameters: mass M, spin J and charge Q. Within classical general relativity, the most important and challenging open problem in black-hole perturbation theory is the study of gravitational and electromagnetic fields in the Kerr-Newman geometry, because of the indissoluble coupling of the perturbation functions. Here we circumvent this long-standing problem by working in the slow-rotation limit. We compute the quasinormal modes up to linear order in J for any value of Q and provide the first, fully-consistent stability analysis of the Kerr-Newman metric. For scalar perturbations the quasinormal modes can be computed exactly, and we demonstrate that the method is accurate within 3% for spins J/Jmax<~0.5, where Jmax is the maximum allowed spin for any value of Q. Quite remarkably, we find numerical evidence that the axial and polar sectors of the gravito-electromagnetic perturbat...
Sadowski, A; Penna, R; Zhu, Y
2013-01-01
A set of long-duration general relativistic magnetohydrodynamic simulations of radiatively inefficient accretion discs around rotating black holes are presented, and are used to estimate the energy, mass and momentum outflow rates from such systems. Outflows occur via two fairly distinct modes: a relativistic jet and a sub-relativistic wind. The jet power depends strongly on the black hole spin and on the magnetic flux at the horizon. Unless these are very small, the energy output in the jet dominates over that in the wind. In the limit of a rapidly spinning black hole accreting in the magnetically arrested limit, when the magnetic flux at the black hole is maximum, the jet power exceeds the total rate of accretion of rest mass energy. However, because of strong collimation, the jet probably does not have a significant effect on its surrounding. In the case of an accreting supermassive black hole, external feedback via a jet is likely important only on the largest galaxy cluster scales. The power in the wind ...
Electrically charged black hole solutions in generalized gauge field theories
Energy Technology Data Exchange (ETDEWEB)
Diaz-Alonso, J; Rubiera-Garcia, D, E-mail: joaquin.diaz@obspm.fr, E-mail: diego.rubiera-garcia@obspm.fr [LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot. 5 Place Jules Janssen, 92190 Meudon (France); Departamento de Fisica, Universidad de Oviedo. Avda. Calvo Sotelo 18, 33007 Oviedo, Asturias (Spain)
2011-09-22
We summarize the main features of a class of anomalous (asymptotically flat, but non Schwarzschild-like) gravitational configurations in models of gravitating non-linear electrodynamics (G-NED) whose Lagrangian densities are defined as arbitrary functions of the two field invariants and constrained by several physical admissibility conditions. This class of models and their associated electrostatic spherically symmetric black hole (ESSBH) solutions are characterized by the behaviours of the Lagrangian densities around the vacuum and at the boundary of their domain of definition.
Applications of gauge/gravity dualities with charged Anti-de Sitter black holes
Energy Technology Data Exchange (ETDEWEB)
Grass, Viviane Theresa
2010-05-17
In this thesis, we deal with different applications of the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence. The AdS/CFT correspondence, which is also more generally referred to as gauge/gravity duality, is a conjectured duality in superstring theory between strongly-coupled four-dimensional N=4 superconformal Yang-Mills theory and weakly-coupled type IIB string theory in five-dimensional AdS spacetime. This duality provides a powerful method to investigate strongly-coupled low-energy systems in four dimensions by substitutionally carrying out calculations in five-dimensional weakly-coupled supergravity. In this work, we use the AdS/CFT correspondence to explore three different strongly-coupled systems, namely a brane world accommodating a strongly-coupled field theory, a strongly-coupled fluid on a three-sphere and a strongly-coupled p-wave superfluid. In all these cases, the dual supergravity descriptions involve charged AdS black holes. The first system studied here is a Randall-Sundrum brane world moving in the background of a five-dimensional non-extremal black hole of N=2 gauged supergravity. The equations of motion of the brane are found to be equal to the Friedmann-Robertson-Walker (FRW) equations for a closed universe. The closed brane universe has special thermodynamic properties. The energy of the brane field theory exhibits a subextensive Casimir contribution, and the entropy can be expressed as a Cardy-Verlinde-type formula. We show that the equations for both quantities can take forms that strongly resemble the two FRW equations. At the horizon of the black hole, these two sets of equations are shown to even merge with each other which might suggest the existence of a common underlying theory. In addition, as a by-product result, the non-extremal black hole solutions considered here are found to admit an alternative description in terms of first-order flow equations similar to those which are well-known from the attractor mechanism of
New Charged Black Holes with Conformal Scalar Hair
Anabalon, Andres
2009-01-01
A general class of four dimensional, stationary solutions of the Einstein-Maxwell system with a conformally coupled scalar field is constructed in this paper. The stationary case is presented and shown to belong to the Plebanski-Demianski family which implies that the static metric has the form of the C-metric. It is shown that in the static, AdS case, a new family of Black Holes arises. They turn out to be cohomogeneity two, with horizons that are not Einstein neither homogenous manifolds. The usual conical singularities present in the C-metric are automatically removed from the spacetime due to the backreaction of the scalar field. The scalar field carries a continuous parameter that resembles the usual acceleration present in the C-metric. When this parameter vanishes the static family it is shown to contain either to the dyonic Bocharova-Bronnikov-Melnikov-Bekenstein solution or the dyonic extension of the Martinez-Troncoso-Zanelli black holes, depending on the value of the cosmological constant.
Proof of the area-angular momentum-charge inequality for axisymmetric black holes
Clement, María E Gabach; Reiris, Martín
2012-01-01
We give a comprehensive discussion, including a detailed proof, of the area-angular momentum-charge inequality for axisymmetric black holes. We analyze the inequality from several viewpoints, in particular including aspects with a theoretical interest well beyond the Einstein-Maxwell theory.
The Central Charge of the Warped AdS^3 Black Hole
Gupta, Kumar S; Sen, Siddhartha; Sivakumar, M
2010-01-01
The AdS/CFT conjecture offers the possibility of a quantum description for a black hole in terms of a CFT. This has ledto the study of general AdS^3 type black holes with a view to constructing an explicit toy quantum black hole model. Such a CFT description would be characterized by its central charge and the dimensions of its primary fields. Recently the expression for the central charges (C_L, C_R) of the CFT dual to the warped AdS^3 have been determined using asymptotic symmetry arguments. The central charges depend, as expected, on the warping factor. We show that topological arguments, used by Witten to constrain central charges for the BTZ black hole, can be generalized to deal with the warped AdS^3 case. Topology constrains the warped factor to be rational numbers while quasinormal modes are conjectured to give the dimensions of primary fields. We find that in the limit when warping is large or when it takes special rational values the system tends to Witten's conjectured unique CFT's with central cha...
On the universality of thermodynamics and $\\eta/s$ ratio for the charged Lovelock black branes
Cadoni, Mariano; Tuveri, Matteo
2016-01-01
We investigate general features of charged Lovelock black branes by giving a detailed description of geometrical, thermodynamic and holographic properties of charged Gauss-Bonnet (GB) black branes in five dimensions. We show that when expressed in terms of effective physical parameters, the thermodynamic behaviour of charged GB black branes is completely indistinguishable from that of charged Einstein black branes. Moreover, the extremal, near-horizon limit of the two classes of branes is exactly the same as they allow for the same AdS$_2\\times R_3$, near-horizon, exact solution. This implies that, although in the UV the associated dual QFTs are different, they flow in the IR to the same fixed point. The calculation of the shear viscosity to entropy ratio $\\eta/s$ confirms these results. Despite the GB dual plasma has in general a non-universal temperature-dependent $\\eta/s$, it flows monotonically to the universal value $1/4\\pi$ in the IR. For negative (positive) GB coupling constant, $\\eta/s$ is an increasi...
BPS-like bound and thermodynamics of the charged BTZ black hole
Cadoni, M
2009-01-01
The charged Banados-Teitelboim-Zanelli (BTZ) black hole is plagued by several pathologies: a) Presence of divergent boundary terms in the action, hence of a divergent black hole mass; b) Once a finite, renormalized, mass M is defined black hole states exist for arbitrarily negative values of M; c) There is no upper bound on the charge Q. We show that these pathological features are an artifact of the renormalization procedure. They can be completely removed by using an alternative renormalization scheme leading to a different definition M_0 of the black hole mass, which is the total energy inside the horizon. The new mass satisfies a BPS-like bound M_0\\ge (\\pi/2)Q^2 and the heat capacity of the hole is positive. We also discuss the black hole thermodynamics that arises when M_0 is interpreted as the internal energy of the system. We show, using three independent approaches (black hole thermodynamics, Einstein equations, Euclidean action formulation) that M_0 satisfies the first law if a term describing the me...
BPS-like bound and thermodynamics of the charged BTZ black hole
Cadoni, Mariano; Monni, Cristina
2009-07-01
The charged Bañados-Teitelboim-Zanelli (BTZ) black hole is plagued by several pathologies: (a) Divergent boundary terms are present in the action; hence, we have a divergent black-hole mass. (b) Once a finite, renormalized, mass M is defined, black-hole states exist for arbitrarily negative values of M. (c) There is no upper bound on the charge Q. We show that these pathological features are an artifact of the renormalization procedure. They can be completely removed by using an alternative renormalization scheme leading to a different definition M0 of the black-hole mass, which is the total energy inside the horizon. The new mass satisfies a BPS-like bound M0≥(π)/(2)Q2, and the heat capacity of the hole is positive. We also discuss the black-hole thermodynamics that arises when M0 is interpreted as the internal energy of the system. We show, using three independent approaches (black-hole thermodynamics, Einstein equations, and Euclidean action formulation), that M0 satisfies the first law if a term describing the mechanical work done by the electrostatic pressure is introduced.
Hawking Radiation of Warped Anti de Sitter and Rotating Hairy Black Holes with Scalar Hair
Gursel, H
2015-01-01
This thesis mainly focuses on the Hawking radiation (HR) evacuating from the surface of the objects that have earned a reputation as the most extraordinary objects existing so far; the black holes (BHs). Throughout this study, quantum tunneling (QT) process serves as the model for the HR of scalar, vector and Dirac particles. The scalar and Dirac particles are anticipated to be tunneling through the horizon of rotating scalar hairy black holes (RHSBHs); whilst the vector particles are associated with a rotating warped anti de-Sitter black hole (WAdS3BH) embedded in a (2+1) dimensional fabric. It is no coincidence that for all three cases; the standard HT expression is derived. Additionally, the engagement of conformal field theory (CFT) with anti de-Sitter (AdS) space presents itself to the reader and the methodologies of Klein-Gordon equation (KGE), Dirac equation and Proca equations (PEs) are introduced. For all three cases, Hamilton-Jacobi (HJ) approach is used, together with Wentzel-Kramers-Brillouin (WKB...
Phase transition in extended thermodynamic phase space and charged Horava-Lifshitz black holes
Poshteh, Mohammad Bagher Jahani
2016-01-01
For charged black holes in Horava-Lifshitz gravity, it is shown that a second order phase transition takes place in extended phase space. We study the behavior of specific heat and free energy at the point of transition in canonical and grand canonical ensembles and show that the black hole falls into a state which is locally and globally stable. We relate the second order nature of phase transition to the fact that the phase transition occurs at a sharp temperature and not over a temperature interval. By taking cosmological constant as thermodynamic pressure for charged black holes, we extend Ehrenfest's equations. We obtain nine equations and show that, all of them are satisfied at the point in which the specific heat diverges. We also apply geometrothermodynamics to extended phase space and show that the scalar curvature of Quevedo metric diverges at the point at which the second order phase transition takes place.
Phase structures of 4D stringy charged black holes in canonical ensemble
Jia, Qiang; Tan, Xiao-Jun
2016-01-01
We study the thermodynamics and phase structures of the asymptotically flat dilatonic black holes in 4 dimensions, placed in a cavity {\\it a la} York, in string theory for an arbitrary dilaton coupling. We consider these charged black systems in canonical ensemble for which the temperature at the wall of and the charge inside the cavity are fixed. We find that the dilaton coupling plays the key role in the underlying phase structures. The connection of these black holes to higher dimensional brane systems via diagonal (double) and/or direct dimensional reductions indicates that the phase structures of the former may exhaust all possible ones of the latter, which are more difficult to study, under conditions of similar settings. Our study also shows that a diagonal (double) dimensional reduction preserves the underlying phase structure while a direct dimensional reduction has the potential to change it.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
Pu, Jin; Han, Yan
2016-08-01
In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
Pu, Jin; Han, Yan
2016-12-01
In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.
Moller's Energy in the Dyadosphere of a Charged Black Hole
Aydogdu, O; Aydogdu, Oktay; Salti, Mustafa
2006-01-01
We use the M{\\o}ller energy-momentum complex both in general relativity and teleparallel gravity to evaluate energy distribution (due to matter plus fields including gravity) in the dyadosphere region for Reissner-Nordstr{\\"o}m black hole. We found the same and acceptable energy distribution in these different approaches of the M{\\o}ller energy-momentum complex. Our teleparallel gravitational result is also independent of the teleparallel dimensionless coupling constant, which means that it is valid in any teleparallel model. This paper sustains (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given space-time and (b) the viewpoint of Lessner that the M{\\o}ller energy-momentum complex is a powerful concept for energy and momentum.
Time domain analysis of superradiant instability for the charged stringy black hole-mirror system
Li, Ran; Zhang, Hongbao; Zhao, Junkun
2015-01-01
It has been proved that the charged stringy black holes are stable under the perturbations of massive charged scalar fields. However, superradiant instability can be generated by adding the mirror-like boundary condition to the composed system of charged stringy black hole and scalar field. The unstable boxed quasinormal modes have been calculated by using both analytical and numerical method. In this paper, we further provide a time domain analysis by performing a long time evolution of charged scalar field configuration in the background of the charged stringy black hole with the mirror-like boundary condition imposed. We have used the ingoing Eddington-Finkelstein coordinates to derive the evolution equation, and adopted Pseudo-spectral method and the forth-order Runge-Kutta method to evolve the scalar field with the initial Gaussian wave packet. It is shown by our numerical scheme that Fourier transforming the evolution data coincides well with the unstable modes computed from frequency domain analysis. T...
Universal charge-mass relation: From black holes to atomic nuclei
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar, E-mail: shaharhod@gmail.co [The Ruppin Academic Center, Emeq Hefer 40250 (Israel); The Hadassah Institute, Jerusalem 91010 (Israel)
2010-10-04
The cosmic censorship hypothesis, introduced by Penrose forty years ago, is one of the corner stones of general relativity. This conjecture asserts that spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. The elimination of a black-hole horizon is ruled out by this principle because that would expose naked singularities to distant observers. We test the consistency of this prediction in a gedanken experiment in which a charged object is swallowed by a charged black hole. We find that the validity of the cosmic censorship conjecture requires the existence of a charge-mass bound of the form q{<=}{mu}{sup 2/3}E{sub c}{sup -1/3}, where q and {mu} are the charge and mass of the physical system respectively, and E{sub c} is the critical electric field for pair-production. Applying this bound to charged atomic nuclei, one finds an upper limit on the number Z of protons in a nucleus of given mass number A: Z{<=}Z{sup *}={alpha}{sup -1/3}A{sup 2/3}, where {alpha}=e{sup 2}/h is the fine structure constant. We test the validity of this novel bound against the (Z,A)-relation of atomic nuclei as deduced from the Weizsaecker semi-empirical mass formula.
NUT-charged black holes in matter-coupled N=2, D=4 gauged supergravity
Colleoni, Marta; Klemm, Dietmar
2012-06-01
Using the results of Cacciatori, Klemm, Mansi, and Zorzan [J. High Energy Phys.JHEPFG1029-8479 05 (2008) 09710.1088/1126-6708/2008/05/097], where all timelike supersymmetric backgrounds of N=2, D=4 matter-coupled supergravity with Fayet-Iliopoulos gauging were classified, we construct genuine NUT-charged BPS black holes in anti-deSitter4 with nonconstant moduli. The calculations are exemplified for the SU(1,1)/U(1) model with prepotential F=-iX0X1. The resulting supersymmetric black holes have a hyperbolic horizon and carry two electric, two magnetic, and one NUT charge, which are however not all independent, but are given in terms of three free parameters. We find that turning on a NUT charge lifts the flat directions in the effective black hole potential, such that the horizon values of the scalars are completely fixed by the charges. We also oxidize the solutions to 11 dimensions, and find that they generalize the geometry found in the work of Gauntlett, Kim, Pakis, and Waldram [Phys. Rev. DPRVDAQ0556-2821 65, 026003 (2001)10.1103/PhysRevD.65.026003] corresponding to membranes wrapping holomorphic curves in a Calabi-Yau fivefold. Finally, a class of NUT-charged Nernst branes is constructed as well, but these have curvature singularities at the horizon.
Abbott-Deser-Tekin Charge of Dilaton Black Holes with Squashed Horizons
Institute of Scientific and Technical Information of China (English)
Jun-Jin Peng; Wen-Chang Xiang; Shao-Hong Cai
2016-01-01
We consider the conserved charge of static black holes with squashed horizons in the Einstein-Maxwell-dilaton theory via both the Abbott-Deser-Tekin (ADT) method and its off-shell generalization.We first make use of the original ADT method to compute the mass of the dilaton squashed black holes in terms of three different reference spacetimes,which are the asymptotic geometry,the fiat background and the spacetime of the KaluzaKlein monopole with boundary matched to the original metric,respectively.Each mass satisfies the first law of black hole thermodynamics,although the mass computed on the basis of the boundary matching the KaluzaKlein monopole is different from that of the other two reference spacetimes.Then the mass of the black holes is evaluated through the off-shell generalized ADT method.
Near-horizon circular orbits and extremal limit for dirty rotating black holes
Zaslavskii, O B
2015-01-01
We consider generic rotating axially symmetric "dirty" (surrounded by matter) black holes. Near-horizon circular equatorial orbits are examined in two different cases of near-extremal (small surface gravity $\\kappa $) and exactly extremal black holes. This has a number of qualitative distinctions. In the first case, it is shown that such orbits can lie as close to the horizon as one wishes on suitably chosen slices of space-time when $\\kappa \\rightarrow 0$. This generalizes observation of T.\\ Jacobson Class. Quantum Grav. 28 187001 (2011) made for the Kerr metric. If a black hole is extremal ($\\kappa =0$), circular on-horizon orbits are impossible for massive particles but, in general, are possible in its vicinity. The corresponding black hole parameters determine also the rate with which a fine-tuned particle on the noncircular near-horizon orbit asymptotically approaches the horizon. Properties of orbits under discussion are also related to the Ba% \\~{n}ados-Silk-West effect of high energy collisions near b...
O'Sullivan, Stephen
2014-01-01
Tidal coupling between members of a compact binary system can have an interesting and important influence on that binary's dynamical inspiral. Tidal coupling also distorts the binary's members, changing them (at lowest order) from spheres to ellipsoids. At least in the limit of fluid bodies and Newtonian gravity, there are simple connections between the geometry of the distorted ellipsoid and the impact of tides on the orbit's evolution. In this paper, we develop tools for investigating tidal distortions of rapidly rotating black holes using techniques that are good for strong-field, fast-motion binary orbits. We use black hole perturbation theory, so our results assume extreme mass ratios. We develop tools to compute the distortion to a black hole's curvature for any spin parameter, and for tidal fields arising from any bound orbit, in the frequency domain. We also develop tools to visualize the horizon's distortion for black hole spin $a/M \\le \\sqrt{3}/2$ (leaving the more complicated $a/M > \\sqrt{3}/2$ cas...
Jet magnetically accelerated from disk-corona around a rotating black hole
Gong, Xiaolong
2012-01-01
A jet acceleration model for extracting energy from disk-corona surrounding a rotating black hole is proposed. In the disk-corona scenario, we obtain the ratio of the power dissipated in the corona to the total for such disk-corona system by solving the disk dynamics equations. The analytical expression of the jet power is derived based on the electronic circuit theory of the magnetosphere. It is shown that jet power increases with the increasing black hole (BH) spin, and concentrates in the inner region of the disk-corona. In addition, we use a sample consisting of 37 radio loud quasars to explore their jet production mechanism, and show that our jet formation mechanism can simulate almost all sources with high power jet, that fail to be explained by the Blandford-Znajek (BZ) process.
Quantum tunneling from rotating black holes with scalar hair in three dimensions
Energy Technology Data Exchange (ETDEWEB)
Sakalli, I.; Gursel, H. [Eastern Mediterranean University, Department of Physics, Mersin-10 (Turkey)
2016-06-15
We study the Hawking radiation of scalar and Dirac particles (fermions) emitted from a rotating scalar hair black hole (RSHBH) within the context of three dimensional (3D) Einstein gravity using non-minimally coupled scalar field theory. Amalgamating the quantum tunneling approach with the Wentzel-Kramers-Brillouin approximation, we obtain the tunneling rates of the outgoing particles across the event horizon. Inserting the resultant tunneling rates into the Boltzmann formula, we then obtain the Hawking temperature (T{sub H}) of the 3D RSHBH. (orig.)
Quantum tunneling from rotating black holes with scalar hair in three dimensions
Sakalli, I
2015-01-01
We study the Hawking radiation (HR) of scalar and Dirac particles (fermions) emitted from a rotating scalar hair black hole (RSHBH) within the context of three dimensional ($3D$) Einstein gravity using non-minimally coupled scalar field theory. Amalgamating the quantum tunneling approach with the Wentzel--Kramers--Brillouin (WKB) approximation, we obtain the tunneling rates of the outgoing particles across the event horizon. Inserting the resultant tunneling rates into the Boltzmann formula, we then obtain the Hawking temperature ($T_{H}$) of the $3D$ RSHBH.
Kazempour, Sobhan; Soroushfar, Saheb
2016-01-01
In this paper we add a compact dimension to Schwarzschild-(anti-) de sitter and Kerr-(anti-) de sitter spacetimes, which describes (rotating) black string-(anti-) de sitter spacetime. We study the geodesic motion of test particles and light rays in this spacetime. We present the analytical solutions of the geodesic equations in terms of Weierstrass elliptic and Kleinian sigma hyperelliptical functions. We also discuss the possible orbits and classify them according to particle's energy and angular momentum. Moreover, the obtained results, are compared to Schwarzschild-(anti-) de sitter and Kerr-(anti-) de sitter spacetimes.
Quantum tunneling from rotating black holes with scalar hair in three dimensions
Sakalli, I.; Gursel, H.
2016-06-01
We study the Hawking radiation of scalar and Dirac particles (fermions) emitted from a rotating scalar hair black hole (RSHBH) within the context of three dimensional (3 D) Einstein gravity using non-minimally coupled scalar field theory. Amalgamating the quantum tunneling approach with the Wentzel-Kramers-Brillouin approximation, we obtain the tunneling rates of the outgoing particles across the event horizon. Inserting the resultant tunneling rates into the Boltzmann formula, we then obtain the Hawking temperature (T_H) of the 3 D RSHBH.
Van der Waals-like behaviour of charged black holes and hysteresis in the dual QFTs
Directory of Open Access Journals (Sweden)
Mariano Cadoni
2017-05-01
Full Text Available Using the rules of the AdS/CFT correspondence, we compute the spherical analogue of the shear viscosity, defined in terms of the retarded Green function for the stress-energy tensor for QFTs dual to five-dimensional charged black holes of general relativity with a negative cosmological constant. We show that the ratio between this quantity and the entropy density, η˜/s, exhibits a temperature-dependent hysteresis. We argue that this hysteretic behaviour can be explained by the Van der Waals-like character of charged black holes, considered as thermodynamical systems. Under the critical charge, hysteresis emerges owing to the presence of two stable states (small and large black holes connected by a meta-stable region (intermediate black holes. A potential barrier prevents the equilibrium path between the two stable states; the system evolution must occur through the meta-stable region, and a path-dependence of η˜/s is generated.
Critical phenomena in higher curvature charged AdS black holes
Lala, Arindam
2012-01-01
In this paper we have studied the critical phenomena in higher curvature charged black holes in the anti-de Sitter (AdS) space-time. As an example we have considered the third order Lovelock-Born-Infeld black holes in AdS space-time. We have analytically derived the thermodynamic quantities of the system. Our analysis revealed the onset of a higher order phase transition in the black hole leading to an infinite discontinuity in the specific heat at constant charge at the critical points. Our entire analysis is based on the canonical framework where we have fixed the charge of the black hole. In an attempt to study the behavior of the thermodynamic quantities near the critical points we have derived the critical exponents of the system explicitly. Although the values of the critical points have been determined numerically, the critical exponents are calculated analytically. Our results fit well with the thermodynamic scaling laws. The scaling hypothesis is also seen to be consistent with these scaling laws. We...
Thermodynamics of charged black holes in Einstein-Horndeski-Maxwell theory
Feng, Xing-Hui; Liu, Hai-Shan; Lü, H.; Pope, C. N.
2016-02-01
We extend an earlier investigation of the thermodynamics of static black holes in an Einstein-Horndeski theory of gravity coupled to a scalar field, by including now an electromagnetic field as well. By studying the two-parameter families of charged static black holes, we obtain much more powerful constraints on the thermodynamics since, unlike in the uncharged one-parameter case, now the right-hand side of the first law is not automatically integrable. In fact, this allows us to demonstrate that there must be an additional contribution in the first law, over and above the usual terms expected for charged black holes. The origin of the extra contribution can be attributed to the behavior of the scalar field on the horizon of the black hole. We carry out the calculations in four dimensions and also in general dimensions. We also derive the ratio of viscosity to entropy for the dual boundary field theory, showing that the usual viscosity bound for isotropic solutions can be violated, with the ratio depending on the mass and charge.
Perturbations of slowly rotating black holes: massive vector fields in the Kerr metric
Pani, Paolo; Gualtieri, Leonardo; Berti, Emanuele; Ishibashi, Akihiro
2012-01-01
We discuss a general method to study linear perturbations of slowly rotating black holes which is valid for any perturbation field, and particularly advantageous when the field equations are not separable. As an illustration of the method we investigate massive vector (Proca) perturbations in the Kerr metric, which do not appear to be separable in the standard Teukolsky formalism. Working in a perturbative scheme, we discuss two important effects induced by rotation: a Zeeman-like shift of nonaxisymmetric quasinormal modes and bound states with different azimuthal number m, and the coupling between axial and polar modes with different multipolar index l. We explicitly compute the perturbation equations up to second order in rotation, but in principle the method can be extended to any order. Working at first order in rotation we show that polar and axial Proca modes can be computed by solving two decoupled sets of equations, and we derive a single master equation describing axial perturbations of spin s=0 and ...
Strong subadditivity, null energy condition and charged black holes
Energy Technology Data Exchange (ETDEWEB)
Caceres, Elena [Facultad de Ciencias, Universidad de Colima,Bernal Diaz del Castillo 340, Colima (Mexico); Theory Group, Department of Physics, The University of Texas,Austin, TX 78712 (United States); Kundu, Arnab [Theory Group, Department of Physics, The University of Texas,Austin, TX 78712 (United States); Pedraza, Juan F.; Tangarife, Walter [Theory Group, Department of Physics, The University of Texas,Austin, TX 78712 (United States); Texas Cosmology Center, The University of Texas,Austin, TX 78712 (United States)
2014-01-16
Using the Hubeny-Rangamani-Takayanagi (HRT) conjectured formula for entanglement entropy in the context of the AdS/CFT correspondence with time-dependent backgrounds, we investigate the relation between the bulk null energy condition (NEC) of the stress-energy tensor with the strong sub-additivity (SSA) property of entanglement entropy in the boundary theory. In a background that interpolates between an AdS to an AdS-Reissner-Nordstrom-type geometry, we find that generically there always exists a critical surface beyond which the violation of NEC would naively occur. However, the extremal area surfaces that determine the entanglement entropy for the boundary theory, can penetrate into this forbidden region only for certain choices for the mass and the charge functions in the background. This penetration is then perceived as the violation of SSA in the boundary theory. We also find that this happens only when the critical surface lies above the apparent horizon, but not otherwise. We conjecture that SSA, which is thus non-trivially related to NEC, also characterizes the entire time-evolution process along which the dual field theory may thermalize.
Strong Subadditivity, Null Energy Condition and Charged Black Holes
Caceres, Elena; Pedraza, Juan F; Tangarife, Walter
2014-01-01
Using the Hubeny-Rangamani-Takayanagi (HRT) conjectured formula for entanglement entropy in the context of the AdS/CFT correspondence with time-dependent backgrounds, we investigate the relation between the bulk null energy condition (NEC) of the stress-energy tensor with the strong sub-additivity (SSA) property of entanglement entropy in the boundary theory. In a background that interpolates between an AdS to an AdS-Reissner-Nordstrom-type geometry, we find that generically there always exists a critical surface beyond which the violation of NEC would naively occur. However, the extremal area surfaces that determine the entanglement entropy for the boundary theory, can penetrate into this forbidden region only for certain choices for the mass and the charge functions in the background. This penetration is then perceived as the violation of SSA in the boundary theory. We also find that this happens only when the critical surface lies above the apparent horizon, but not otherwise. We conjecture that SSA, which...
Rotating black holes in Einstein-Dilaton-Gauss-Bonnet gravity with finite coupling
Maselli, Andrea; Gualtieri, Leonardo; Ferrari, Valeria
2015-01-01
Among various strong-curvature extensions to General Relativity, Einstein-Dilaton-Gauss-Bonnet gravity stands out as the only nontrivial theory containing quadratic curvature corrections while being free from the Ostrogradsky instability to any order in the coupling parameter. We derive an approximate stationary and axisymmetric black-hole solution of this gravitational theory in closed form, which is quadratic in the black-hole spin angular momentum and of seventh order in the coupling parameter of the theory. This extends previous work that obtained the corrections to the metric only at the leading order in the coupling parameter, and allows us to consider values of the coupling parameter close to the maximum permitted by theoretical constraints. We compute some geometrical properties of this solution, such as the dilaton charge, the moment of inertia and the quadrupole moment, and its geodesic structure, including the innermost-stable circular orbit and the epicyclic frequencies for massive particles. The ...
Pair Production, Vacuum Polarization and Anomaly in (A)dS and Charged Black Holes
Kim, Sang Pyo
2016-01-01
We explore the connection between the distribution of particles spontaneously produced from an electric field or black hole and the vacuum persistence, twice the imaginary part of the one-loop effective action. Employing the reconstruction conjecture, we find the effective action for the Bose-Einstein or Fermi-Dirac distribution. The Schwinger effect in ${\\rm AdS}_2$ is computed via the phase-integral method in the static coordinates. The Hawking radiation and Schwinger effect of a charged black hole is rederived and interpreted via the phase-integral. Finally, we discuss the relation between the vacuum persistence and the trace or gravitational anomalies.
Spherical Accretion of Matter by Charged Black Holes on f(T) Gravity
Rodrigues, Manuel E
2016-01-01
We studied the spherical accretion of matter by charged black holes on $f(T)$ Gravity. Considering the accretion model of a isentropic perfect fluid we obtain the general form of the Hamiltonian and the dynamic system for the fluid. We have analysed the movements of an isothermal fluid model with $p=\\omega e$ and where $p$ is the pressure and $e$ the total energy density. The analysis of the cases shows the possibility of spherical accretion of fluid by black holes, revealing new phenomena as cyclical movement inside the event horizon.
On five-dimensional non-extremal charged black holes and FRW cosmology
Lópes-Cardoso, G
2008-01-01
We consider static non-extremal charged black hole solutions in the context of N=2 gauged supergravity theories in five dimensions, and we show that they satisfy first-order flow equations. Then we analyze the motion of the dual brane in these black hole backgrounds. We express the entropy in terms of a Cardy-Verlinde-type formula, and we show that the equations describing the FRW cosmology on the brane have a form that is similar to the equations for the entropy and for the Casimir energy on the brane. We also briefly comment on the inclusion of a Gauss-Bonnet term in the analysis.
Quasinormal modes of four-dimensional topological nonlinear charged Lifshitz black holes
Energy Technology Data Exchange (ETDEWEB)
Becar, Ramon [Universidad Cato lica de Temuco, Departamento de Ciencias Matematicas y Fisicas, Temuco (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)
2016-02-15
We study scalar perturbations of four- dimensional topological nonlinear charged Lifshitz black holes with spherical and plane transverse sections, and we find numerically the quasinormal modes for scalar fields. Then we study the stability of these black holes under massive and massless scalar field perturbations. We focus our study on the dependence of the dynamical exponent, the nonlinear exponent, the angular momentum, and the mass of the scalar field in the modes. It is found that the modes are overdamped, depending strongly on the dynamical exponent and the angular momentum of the scalar field for a spherical transverse section. In contrast, for plane transverse sections the modes are always overdamped. (orig.)
On conserved charges and thermodynamics of the AdS4 dyonic black hole
Cárdenas, Marcela; Fuentealba, Oscar; Matulich, Javier
2016-05-01
We consider four-dimensional gravity in the presence of a dilatonic scalar field and an Abelian gauge field. This theory corresponds to the bosonic sector of a Kaluza-Klein reduction of eleven-dimensional supergravity which induces a specific self-interacting potential for the scalar field. We compute the conserved charges and carry out the thermodynamics of an anti-de Sitter (AdS) dyonic black hole solution that was proposed recently. The charges coming from symmetries of the action are computed using the Regge-Teitelboim Hamiltonian approach. They correspond to the mass, which acquires contributions from the scalar field, and the electric charge. We introduce integrability conditions because the scalar field leads to non-integrable terms in the variation of the mass. These conditions are generically solved by introducing boundary conditions that relate the leading and subleading terms of the scalar field fall-off. The Hamiltonian Euclidean action, computed in the grand canonical ensemble, is obtained by demanding the action to have an extremum. Its value is given by a radial boundary term plus an additional polar angle boundary term due to the presence of a magnetic monopole. Remarkably, the magnetic charge can be identified from the variation of the additional polar angle boundary term, confirming that the first law of black hole thermodynamics is a consequence of having a well-defined and finite Hamiltonian action principle, even if the charge does not come from a symmetry of the action. The temperature and electrostatic potential are determined by demanding regularity of the black hole solution, whereas the value of the magnetic potential is determined by the variation of the additional polar angle boundary term. Consequently, the first law of black hole thermodynamics is identically satisfied by construction.
Energy and spatial momentum of charged rotating frames in tetrad gravity
Institute of Scientific and Technical Information of China (English)
Gamal G.L. Nashed
2011-01-01
We compute the total energy and the spatial momentum of four charged rotating (Kerr-Newman) frames by using the gravitational energy-momentum 3-form within the framework of the tetrad formulation of the general relativity theory.We show how the effect of the inertial always makes the total energy divergent.We use a natural regularization method,which yields the physical value for the total energy of the system.We show how the regularization method works on a number of different rotating frames that are related to each other by the local Lorentz transformation.We also show that the inertial has no effect on the spatial momentum components.
Magnetohydrodynamic Simulations of A Rotating Massive Star Collapsing to A Black Hole
Fujimoto, S; Kotake, K; Sato, K; Yamada, S; Fujimoto, Shin-ichiro; Hashimoto, Masa-aki; Kotake, Kei; Sato, Katsuhiko; Yamada, Shoichi
2006-01-01
We perform two-dimensional, axisymmetric, magnetohydrodynamic simulations of the collapse of a rotating star of 40 Msun and in the light of the collapsar model of gamma-ray burst. Considering two distributions of angular momentum, up to \\sim 10^{17} cm^2/s, and the uniform vertical magnetic field, we investigate the formation of an accretion disk around a black hole and the jet production near the hole. After material reaches to the black hole with the high angular momentum, the disk is formed inside a surface of weak shock. The disk becomes in a quasi-steady state for stars whose magnetic field is less than 10^{10} G before the collapse. We find that the jet can be driven by the magnetic fields even if the central core does not rotate as rapidly as previously assumed and outer layers of the star has sufficiently high angular momentum. The magnetic fields are chiefly amplified inside the disk due to the compression and the wrapping of the field. The fields inside the disk propagate to the polar region along t...
Phase transitions in charged topological black holes dressed with a scalar hair
Martínez, Cristián; Montecinos, Alejandra
2010-12-01
Phase transitions in charged topological black holes dressed with a scalar field are studied. These black holes are solutions of the Einstein-Maxwell theory with a negative cosmological constant and a conformally coupled real self-interacting scalar field. Comparing, in the grand canonical ensemble, the free energies of the hairy and undressed black holes two different phase transitions are found. The first of them is one of second-order type and it occurs at a temperature defined by the value of the cosmological constant. Below this temperature an undressed black hole spontaneously acquires a scalar hair. The other phase transition is one of first-order type. The corresponding critical temperature, which is bounded from above by the one of the previous case, strongly depends on the coupling constant of the quartic self-interaction potential, and this transition only appears when the coupling constant is less than a certain value. In this case, below the critical temperature the undressed black hole is thermodynamically favored. However, when the temperature exceeds the critical value a hairy black hole is likely to be occur.
Time evolution of superradiant instabilities for charged black holes in a cavity
Degollado, Juan Carlos
2013-01-01
Frequency domain studies have recently demonstrated that charged scalar fields exhibit fast growing superradiant instabilities when interacting with charged black holes in a cavity. Here, we present a time domain analysis of the long time evolution of test charged scalar field configurations on the Reissner-Nordstr\\"om background, with or without a mirror-like boundary condition. Initial data is taken to be either a Gaussian wave packet or a regularised (near the horizon) quasi-bound state. Then, Fourier transforming the data obtained in the evolution confirms the results obtained in the frequency domain analysis, in particular for the fast growing modes. We show that spherically symmetric (l=0) modes have even faster growth rates than the l=1 modes for `small' field charge. Thus, our study confirms that this setup is particularly promising for considering the non-linear development of the superradiant instability, since the fast growth makes the signal overcome the numerical error that dominates for small gr...
Rahaman, Farook; Sharma, Ranjan; Tiwari, Rishi Kumar
2014-01-01
We report a 3D charged black hole solution in an anti desetter space inspired by noncommutative geometry.In this construction,the black hole exhibits two horizon which turn into a single horizon in the extreme case.We investigate the impacts of the electromagnetic field on the location of the event horizon,mass and thermodynamic properties such as Hawking temperature,entropy and heat capacity of the black hole.The geodesics of the charged black hole are also analyzed.
A Secondary Operator Ordering Problem for a Charged Rigid Planar Rotator in Uniform Magnetic Field
Institute of Scientific and Technical Information of China (English)
XIAO Yan-Ping; LAI Mei-Mei; HOU Ji-Xuan; CHEN Xu-Wen; LIU Quan-Hui
2005-01-01
When the motion of a particle is constrained, an excess term exists using hermitian form of Cartesian momentum pi (i = 1, 2, 3) in usual kinetic energy (1/2μ)∑p2i, and the correct kinetic energy turns out to be (1/2μ) ∑(1/ fi)pifipi, where the fi are dummy factors in classical mechanics and nontrivial in quantum mechanics. In this paper the explicit form of the dummy functions fi is given for a charged rigid planar rotator in the uniform magnetic field.
Integrability in conformally coupled gravity: Taub-NUT spacetimes and rotating black holes
Bardoux, Yannis; Charmousis, Christos
2013-01-01
We consider four dimensional stationary and axially symmetric spacetimes for conformally coupled scalar-tensor theories. We show that, in analogy to the Lewis-Papapetrou problem in General Relativity (GR), the theory at hand can be recast in an analogous integrable form. We give the relevant rod formalism, introduced by Weyl for vacuum GR, explicitly giving the rod structure of the black hole of Bocharova et al. and Bekenstein (BBMB), in complete analogy to the Schwarzschild solution. The additional scalar field is shown to play the role of an extra Weyl potential. We then employ the Ernst method as a concrete solution generating example to obtain the Taub-NUT version of the BBMB hairy black hole, with or without a cosmological constant. We show that the anti-de Sitter hyperbolic version of this solution is free of closed timelike curves that plague usual Taub-NUT metrics, and thus consists of a rotating, asymptotically locally anti-de Sitter black hole. This stationary solution has no curvature singularities...
Influence of frame-dragging on magnetic null points near rotating black hole
Karas, V; Kunneriath, D
2012-01-01
Understanding the mechanisms of particle acceleration from the vicinity of black holes poses a challenge. Electromagnetic effects are thought to be a prime suspect, but details still need an explanation. To this end, we study a three-dimensional structure of oblique magnetic fields near a rotating black hole in vacuum. It has been proposed that such a set-up can lead to efficient acceleration when plasma is injected near a magnetic null point. We focus our attention especially on the magnetic field in the immediate neighborhood of the magnetic null point, which was previously shown to occur in the equatorial plane. By employing the Line-Integral-Convolution (LIC) method, we visualize the magnetic field lines and explore the electric lines rising out of the equatorial plane. We show the magnetic field structure near the boundary of ergosphere, depending on the spin of the black hole. Electric field develops a non-vanishing component passing through the magnetic null point and ensuring efficient acceleration of...
Magnetic Black Holes Are Also Unstable
Kim, Sang Pyo
2004-01-01
Most black holes are known to be unstable to emitting Hawking radiation (in asymptotically flat spacetime). If the black holes are non-extreme, they have positive temperature and emit thermally. If they are extremal rotating black holes, they still spontaneously emit particles like gravitons and photons. If they are extremal electrically charged black holes, they are unstable to emitting electrons or positrons. The only exception would be extreme magnetically charged black holes if there do not exist any magnetic monopoles for them to emit. However, here we show that even in this case, vacuum polarization causes all magnetic black holes to be unstable to emitting smaller magnetic black holes.
Penrose inequalities and a positive mass theorem for charged black holes in higher dimension
de Lima, Levi Lopes; Lozório, Weslley; Silva, Juscelino
2014-01-01
We use the inverse mean curvature flow to establish Penrose-type inequalities for time-symmetric Einstein-Maxwell initial data sets which can be suitably embedded as a hypersurface in Euclidean space $\\mathbb R^{n+1}$, $n\\geq 3$. In particular, we prove a positive mass theorem for this class of charged black holes. As an application we show that the conjectured upper bound for the area in terms of the mass and the charge, which in dimension $n=3$ is relevant in connection with the Cosmic Censorship Conjecture, always holds under the natural assumption that the horizon is stable as a minimal hypersurface.
The Hawking radiation of the charged particle via tunnelling from the axisymmetric Sen black hole
Institute of Scientific and Technical Information of China (English)
Jiang Qing-Quan; Yang Shu-Zheng; Chen De-You
2006-01-01
Extending Parikh's semi-classical quantum tunnelling model, this paper has studied the Hawking radiation of the charged particle via tunnelling from the horizon of the axisymmetric Sen black hole. Different from the uncharged massless particle, the geodesies of the charged massive particle tunnelling from the horizon is not light-like. The derived result supports Parikh's opinion and provides a correct modification to Hawking strictly thermal spectrum developed by the fixed background space-time and not considering the energy conservation and the self-gravitation interaction.
Critical behavior of charged black holes in Gauss-Bonnet gravity`s rainbow
Hendi, Seyed Hossein; Panah, Behzad Eslam; Faizal, Mir; Momennia, Mehrab
2016-01-01
Following an earlier study regarding Gauss-Bonnet-Maxwell black holes in the presence of gravity's rainbow [S. H. Hendi and M. Faizal, Phys. Rev. D 92, 044027 (2015)], in this paper, we will consider all constants as energy dependent ones. The geometrical and thermodynamical properties of this generalization are studied and the validation of the first law of thermodynamics is examined. Next, through the use of proportionality between cosmological constant and thermodynamical pressure, van der Waals-like behavior of these black holes in extended phase space is investigated. An interesting critical behavior for sets of rainbow functions in this case is reported. Also, the critical behavior of uncharged and charged solutions is analyzed and it is shown that the generalization to a charged case puts an energy dependent restriction on values of different parameters.
Energy of a Stringy Charged Black Hole in the Teleparallel Gravity
Salti, M
2006-01-01
We use the teleparallel geometry analog of the Moller energy-momentum complex to calculate the energy distribution (due to matter plus field including gravity) of a charged black hole solution in heterotic string theory. We find the same energy distribution as obtained by Gad who investigated the same problem by using the Moller energy-momentum complex in general relativity. The total energy depends on the black hole mass M and charge Q. The energy obtained is also independent of the teleparallel dimensionless coupling constant, which means that it is valid not only in the teleparallel equivalent of general relativity, but also in any teleparallel model. Furthermore, our results also sustains (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime and (b) the viewpoint of Lessner that the Moller energy-momentum complex is a powerful concept of energy and momentum.
Thermodynamic stability of charged BTZ black holes: Ensemble dependency problem and its solution
Hendi, S H; Mamasani, R
2015-01-01
Motivated by the wide applications of thermal stability and phase transition, we investigate thermodynamic properties of charged BTZ black holes. We apply the standard method to calculate the heat capacity and the Hessian matrix and find that thermal stability of charged BTZ solutions depends on the choice of ensemble. To overcome this problem, we take into account cosmological constant as a thermodynamical variable. By this modification, we show that the ensemble dependency is eliminated and thermal stability conditions are the same in both ensembles. Then, we generalize our solutions to the case of nonlinear electrodynamics. We show how nonlinear matter field modifies the geometrical behavior of the metric function. We also study phase transition and thermal stability of these black holes in context of both canonical and grand canonical ensembles. We show that by considering the cosmological constant as a thermodynamical variable and modifying the Hessian matrix, the ensemble dependency of thermal stability...
Phase transition of charged Black Holes in Brans-Dicke theory through geometrical thermodynamics
Hendi, S H; Panah, B Eslam; Armanfard, Z
2015-01-01
In this paper, we take into account black hole solutions of Brans-Dicke-Maxwell theory and investigate their stability and phase transition points. We apply the concept of geometry in thermodynamics to obtain phase transition points and compare its results with those of calculated in canonical ensemble through heat capacity. We show that these black holes enjoy second order phase transitions. We also show that there is a lower bound for the horizon radius of physical charged black holes in Brans-Dicke theory which is originated from restrictions of positivity of temperature. In addition, we find that employing specific thermodynamical metric in the context of geometrical thermodynamics yields divergencies for thermodynamical Ricci scalar in places of phase transitions. It will be pointed out that due to characteristics behavior of thermodynamical Ricci scalar around its divergence points, one is able to distinguish the physical limitation point from the phase transitions.
Entanglement entropy of charged dilaton-axion black hole and quantum isolated horizon
Yang, Ze-Min; Li, Xiu-Lan; Gao, Ying
2016-09-01
Based on the work of Ghosh and Perez, we calculate the statistical entropy of charged dilaton-axion black hole. In the calculations we take the integral from the position of QIH to infinity, so the obtained entropy is the entanglement entropy outside the QIH. It is shown that only if the position of QIH is properly chosen the leading term of logarithm of the number of quantum states on the QIH is equal to the leading term of the entanglement entropy outside the black hole horizon, and both are the Bekenstein-Hawking entropy. The results reveal the relation between the entanglement entropy of black hole and the logarithm of the number of quantum states.
Phase transitions in higher derivative gravity and gauge theory: R-charged black holes
Dey, Tanay K.; Mukherji, Sudipta; Mukhopadhyay, Subir; Sarkar, Swarnendu
2007-09-01
This is a continuation of our earlier work where we constructed a phenomenologically motivated effective action of the boundary gauge theory at finite temperature and finite gauge coupling on S3 × S1. In this paper, we argue that this effective action qualitatively reproduces the gauge theory representing various bulk phases of R-charged black hole with Gauss-Bonnet correction. We analyze the system both in canonical and grand canonical ensemble.
Phase transitions in higher derivative gravity and gauge theory: R-charged black holes
Dey, Tanay K; Mukhopadhyay, Subir; Sarkar, Swarnendu
2007-01-01
This is a continuation of our earlier work where we constructed a phenomenologically motivated effective action of the boundary gauge theory at finite temperature and finite gauge coupling on $S^3 \\times S^1$. In this paper, we argue that this effective action qualitatively reproduces the gauge theory representing various bulk phases of R-charged black hole with Gauss-Bonnet correction. We analyze the system both in canonical and grand canonical ensemble.
A study of geodesic motion in a (2+1)-dimensional charged BTZ black hole
Soroushfar, Saheb; Jafari, Afsaneh
2015-01-01
This study is purposed to derive the equation of motion for geodesics in vicinity of spacetime of a (2 + 1)-dimensional charged BTZ black hole. In this paper, we solve geodesics for both massive and massless particles in terms of Weierstrass elliptic and Kleinian sigma hyper-elliptic functions. Then we determine different trajectories of motion for particles in terms of conserved energy and angular momentum and also using effective potential.
Flat Symplectic Bundles of N-Extended Supergravities, Central Charges and Black-Hole Entropy
Andrianopoli, Laura; Ferrara, Sergio
1998-01-01
In these lectures we give a geometrical formulation of N-extended supergravities which generalizes N=2 special geometry of N=2 theories. In all these theories duality symmetries are related to the notion of "flat symplectic bundles" and central charges may be defined as "sections" over these bundles. Attractor points giving rise to "fixed scalars" of the horizon geometry and Bekenstein-Hawking entropy formula for extremal black-holes are discussed in some details.
Scattering and Absorption of Gravitational Plane Waves by Rotating Black Holes
Dolan, Sam R
2008-01-01
In this study, we investigate scattering and absorption of planar gravitational waves by a Kerr black hole in vacuum. We compute cross sections for radiation incident along the rotation axis, and consider both co- and counter-rotating circular polarizations. We show that, if a novel series reduction method is employed, the partial wave approach developed by Matzner and coworkers yields accurate results. Phase shifts are computed via a Sasaki-Nakamura transformation, and spheroidal harmonics via a spectral decomposition method. A catalogue of cross sections is presented for a range of parameters ($M\\omega \\le 4$ and $a \\le 0.99M$). In the long- and short-wavelength regimes we find good agreement with perturbative and semi-classical approximations. We confirm that helicity is not conserved: flux scattered in the backward direction has the opposite polarization to the incident radiation. At low frequencies, fast-rotating holes generate superradiance in the $l = 2$, $m = 2$ mode which enhances the back-scattered ...
Rasskazov, Alexander; Merritt, David
2017-01-01
The subject of our study is a binary supermassive black hole (BSBH) in the center of a galactic nucleus. We model the evolution of its orbit due to interactions with the stars of the galaxy by means of 3-body scattering experiments. Our model includes a new degree of freedom - the orientation of the BSBH’s orbital plane - which is allowed to change due to interaction with the stars in a rotating nucleus. The binary’s eccentricity also evolves in an orientation-dependent manner. We find that the dynamics are qualitatively different compared with non-rotating nuclei: 1) The BSBH's orbital plane evolves toward alignment with the plane of rotation of the nucleus; 2) The BSBH’s eccentricity decreases for aligned BSBHs and increases for counter-aligned ones.We then apply our model to calculate the effects of stellar environment on the gravitational wave background spectrum produced by BSBHs. Using the results of recent N-body/Monte-Carlo simulations we account for different rates of stellar interaction in spherical, axisymmetric and triaxial galaxies. We also consider the possibility that SBH masses are systematically lower than usually assumed. The net result of the new physical mechanisms included here is a spectrum for the stochastic gravitational wave background that has a significantly lower amplitude than in previous treatments, which could explain the discrepancy that currently exists between the models and the upper limits set by pulsar timing array observations.
Thermodynamics of Charged Black Holes in Einstein-Horndeski-Maxwell Theory
Feng, Xing-Hui; Lü, H; Pope, C N
2015-01-01
We extend an earlier investigation of the thermodynamics of static black holes in an Einstein-Horndeski theory of gravity coupled to a scalar field, by including now an elec- tromagnetic field as well. By studying the two-parameter families of charged static black holes, we obtain much more powerful constraints on the thermodynamics since, unlike in the uncharged one-parameter case, now the right-hand side of the first law is not automatically integrable. In fact, this allows us to demonstrate that there must be an additional contribution in the first law, over and above the usual terms expected for charged black holes. The origin of the extra contribution can be attributed to the behaviour of the scalar field on the horizon of the black hole. We carry out the calculations in four dimensions and also in general dimensions. We also derive the ratio of viscosity to entropy for the dual boundary field theory, showing that the usual viscosity bound for isotropic solutions can be violated, with the ratio depending...
Back reaction, the Hawking emission spectrum from the charged black hole
Energy Technology Data Exchange (ETDEWEB)
Xu Pingchuan; Wang Zhihong [Institute of Theoretical Physics, China West Normal University, Nanchong, Sichuan 637002 (China); Han Yan, E-mail: pcxu@163.com [College of Mathematic and Information, China West Normal University, Nanchong, Sichuan 637002 (China)
2011-06-21
The Hawking emission spectrum of the Schwarzschild-like black hole has been successfully described in the tunneling picture. In this paper, we develop the idea for the case of the charged black hole with back reaction. First, the most general, static spherically symmetric charged black hole, in the presence of back reaction, has been provided by solving the Einstein equations with a non-zero vacuum expectation value of the energy-momentum tensor (T{sub {mu}{nu}}({phi}, g{sub {mu}{nu}})). At the one-loop corrections, we also produce the modified expressions for the Hawking temperature and Bekenstein-Hawking entropy. It is found that the leading correction to the semiclassical entropy is logarithmic and next to the leading order is inverse of the horizon area, just as the expected well-known results. In particular, as our main focus in this paper, we show that the modified black hole still radiates with a perfect blackbody spectrum, only the temperature undergoing quantum corrections. Also, the Hawking fluxes of the electric current and energy-momentum tensor to include the effect of back reaction are obtained. The results are interestingly found sharing the same form as that from the point of anomaly.
Uniformly rotating neutron stars in the global and local charge neutrality cases
Energy Technology Data Exchange (ETDEWEB)
Belvedere, Riccardo, E-mail: riccardo.belvedere@icra.it [Dipartimento di Fisica and ICRA, Sapienza Universita' di Roma, P.le Aldo Moro 5, I-00185 Rome (Italy); ICRANet, P.zza della Repubblica 10, I-65122 Pescara (Italy); Boshkayev, Kuantay, E-mail: kuantay@icra.it [Physical–Technical Faculty, Al-Farabi Kazakh National University, Al-Farabi ave. 71, 050040 Almaty (Kazakhstan); Rueda, Jorge A., E-mail: jorge.rueda@icra.it [Dipartimento di Fisica and ICRA, Sapienza Universita' di Roma, P.le Aldo Moro 5, I-00185 Rome (Italy); ICRANet, P.zza della Repubblica 10, I-65122 Pescara (Italy); Ruffini, Remo, E-mail: ruffini@icra.it [Dipartimento di Fisica and ICRA, Sapienza Universita' di Roma, P.le Aldo Moro 5, I-00185 Rome (Italy); ICRANet, P.zza della Repubblica 10, I-65122 Pescara (Italy); ICRANet, University of Nice-Sophia Antipolis, 28 Av. de Valrose, 06103 Nice Cedex 2 (France)
2014-01-15
In our previous treatment of neutron stars, we have developed the model fulfilling global and not local charge neutrality. In order to implement such a model, we have shown the essential role by the Thomas–Fermi equations, duly generalized to the case of electromagnetic field equations in a general relativistic framework, forming a coupled system of equations that we have denominated Einstein–Maxwell–Thomas–Fermi (EMTF) equations. From the microphysical point of view, the weak interactions are accounted for by requesting the β stability of the system, and the strong interactions by using the σ–ω–ρ nuclear model, where σ, ω and ρ are the mediator massive vector mesons. Here we examine the equilibrium configurations of slowly rotating neutron stars by using the Hartle formalism in the case of the EMTF equations indicated above. We integrate these equations of equilibrium for different central densities ρ{sub c} and circular angular velocities Ω and compute the mass M, polar R{sub p} and equatorial R{sub eq} radii, angular momentum J, eccentricity ϵ, moment of inertia I, as well as quadrupole moment Q of the configurations. Both the Keplerian mass-shedding limit and the axisymmetric secular instability are used to construct the new mass–radius relation. We compute the maximum and minimum masses and rotation frequencies of neutron stars. We compare and contrast all the results for the global and local charge neutrality cases.
Entropy of an extremal electrically charged thin shell and the extremal black hole
Lemos, José P S; Zaslavskii, Oleg B
2015-01-01
There is a debate as to what is the value of the the entropy $S$ of extremal black holes. There are approaches that yield zero entropy $S=0$, while there are others that yield the Bekenstein-Hawking entropy $S=A_+/4$, in Planck units. There are still other approaches that give that $S$ is proportional to $r_+$ or even that $S$ is a generic well-behaved function of $r_+$. Here $r_+$ is the black hole horizon radius and $A_+=4\\pi r_+^2$ is its horizon area. Using a thin matter shell with extremal electric charge, we find the entropy expression for the extremal thin shell spacetime. When the shell's radius approaches its own gravitational radius, and thus turns into an extremal black hole, we encounter that the entropy is $S=S(r_+)$, i.e., the entropy of an extremal black hole is a function of $r_+$ alone. We speculate that the range of values for the entropy of an extremal black hole is $0\\leq S(r_+) \\leq A_+/4$.
Phase transitions in charged topological black holes dressed with a scalar hair
Martinez, Cristian
2010-01-01
Phase transitions in charged topological black holes dressed with a scalar field are studied. These black holes are solutions of the Einstein-Maxwell theory with a negative cosmological constant and a conformally coupled real self-interacting scalar field. Comparing, in the grand canonical ensemble, the free energies of the hairy and undressed black holes two different phase transitions are found. The first of them is one of second-order type and it occurs at a temperature defined by the value of the cosmological constant. Below this temperature an undressed black hole spontaneously acquires a scalar hair. The other phase transition is one of first-order type. The corresponding critical temperature, which is bounded from above by the one of the previous case, strongly depends on the coupling constant of the quartic self-interaction potential, and this transition only appears when the coupling constant is less than a certain value. In this case, below the critical temperature the undressed black is thermodynam...
Entropy of an extremal electrically charged thin shell and the extremal black hole
Directory of Open Access Journals (Sweden)
José P.S. Lemos
2015-11-01
Full Text Available There is a debate as to what is the value of the entropy S of extremal black holes. There are approaches that yield zero entropy S=0, while there are others that yield the Bekenstein–Hawking entropy S=A+/4, in Planck units. There are still other approaches that give that S is proportional to r+ or even that S is a generic well-behaved function of r+. Here r+ is the black hole horizon radius and A+=4πr+2 is its horizon area. Using a spherically symmetric thin matter shell with extremal electric charge, we find the entropy expression for the extremal thin shell spacetime. When the shell's radius approaches its own gravitational radius, and thus turns into an extremal black hole, we encounter that the entropy is S=S(r+, i.e., the entropy of an extremal black hole is a function of r+ alone. We speculate that the range of values for an extremal black hole is 0≤S(r+≤A+/4.
The Near-Horizon Limit of the Extreme Rotating d=5 Black Hole as a Homogenous Spacetime
Alonso-Alberca, N; Ortín, Tomas; Alonso-Alberca, Natxo; Lozano-Tellechea, Ernesto; Ortin, Tomas
2003-01-01
We show that the spacetime of the near-horizon limit of the extreme rotating d=5 black hole, which is maximally supersymmetric in N=2,d=5 supergravity for any value of the rotation parameter j\\in [-1,1], is a homogeneous non-symmetric spacetime corresponding to the coset [SO(2,1)xSO(3)]/SO(2) in which the subgroup SO(2) acts both on SO(2,1) and on SO(3).
Processing integral-skin polyolefin foams in single-charge rotational foam molding
Pop-Iliev, Remon
This thesis focuses on establishing the scientific and engineering foundations for gaining a fundamental understanding of the mechanisms and critical parameters governing the processing of integral-skin low-density polyolefin foams in rotational foam molding. The presented research is particularly intended to broaden the knowledge in the field of manufacturing adjacent, but clearly distinct, layers of non-cellular and cellular structures, consisting of identical or compatible plastic grades, using a single-charge processing concept. Although this technology is beneficial for the efficacy of the molding process and the structural homogeneity of the moldings, its optimization raised a fairly large number of fundamental issues that had to be resolved through further research. In this context, an attempt has been made to establish rigorous, experimentally validated, theoretical models that describe the phenomena identified as the fundamental challenges of this technology. The major contributions of this thesis include: (i) optimization of the single-charge rotational foam molding process for the manufacture of both PE/PE and PE/PP integral-skin cellular composites, (ii) development of a two-step oven temperature profile that prevents the foamable resins invading the solid skin layer and ensures that skin formation always completes prior to the activation of the foamable resin, (iii) fundamental study of the adherence behavior of powders and foamable pellets to a high-temperature rotating mold wall, (iv) fundamental study of the lifespan of CBA-blown bubbles in non-pressurized non-isothermal polymer melts using hot-stage optical microscopy and digital imaging, (v) development of a detailed theoretical model involving diffusion, surface tension, and viscosity to simulate the observed foaming mechanism, and (vi) fundamental study of the rotofoamablility of polyolefin resins using both dry blending and melt compounding based methods and characterization of rheological and
The charged black-hole bomb: A lower bound on the charge-to-mass ratio of the explosive scalar field
Hod, Shahar
2016-01-01
The well-known superradiant amplification mechanism allows a charged scalar field of proper mass $\\mu$ and electric charge $q$ to extract the Coulomb energy of a charged Reissner-Nordstr\\"om black hole. The rate of energy extraction can grow exponentially in time if the system is placed inside a reflecting cavity which prevents the charged scalar field from escaping to infinity. This composed black-hole-charged-scalar-field-mirror system is known as the {\\it charged black-hole bomb}. Previous numerical studies of this composed physical system have shown that, in the linearized regime, the inequality $q/\\mu>1$ provides a necessary condition for the development of the superradiant instability. In the present paper we use analytical techniques to study the instability properties of the charged black-hole bomb in the regime of linearized scalar fields. In particular, we prove that the lower bound ${{q}\\over{\\mu}}>\\sqrt{{{r_{\\text{m}}/r_--1}\\over{r_{\\text{m}}/r_+-1}}}$ provides a necessary condition for the develo...
First Quantum Correction to Dirac Entropy for Rotating U(1)(×)U(1) Dilaton Black Hole
Institute of Scientific and Technical Information of China (English)
高长军; 沈有根
2002-01-01
The first quantum correction to rotating U(1)(×)U(1) dilaton black hole entropy is calculated by using the improved brick-wall model. We propose not to consider the superradiant mode for the reason that fermion fields do not display superradiance. We found that the nonsuperradiant mode does contribute exactly the first quantum correction to the non-extreme black hole entropy. Moreover, our cut-off Newman-Penrose e which does not require an angular cut-off is independent of angle. As for the extreme black hole, we found that its entropy is zero.
Kazanas, Demosthenes; Fukumura, K.
2009-01-01
We present detailed computations of photon orbits emitted by flares at the ISCO of accretion disks around rotating black holes. We show that for sufficiently large spin parameter, i.e. $a > 0.94 M$, following a flare at ISCO, a sufficient number of photons arrive at an observer after multiple orbits around the black hole, to produce an "photon echo" of constant lag, i.e. independent of the relative phase between the black hole and the observer, of $\\Delta T \\simeq 14 M$. This constant time delay, then, leads to the presence of a QPO in the source power spectrum at a frequency $\
Thermodynamics of higher dimensional topological charged AdS black holes in dilaton gravity
Hendi, S H
2010-01-01
In this paper, we study topological AdS black holes of $(n+1)$-dimensional Einstein-Maxwell-dilaton theory and investigate their properties. We use the area law, surface gravity and Gauss law interpretations to find entropy, temperature and electrical charge, respectively. We also employ the Brown and York subtraction method to calculate the quasilocal mass of the solutions. We obtain a Smarr-type formula for the mass as a function of the entropy and the charge, and compute the temperature and the electric potential through the Smarr-type formula and show that these thermodynamic quantities coincide with their values which are calculated through using the geometry. Finally, we perform a stability analysis in the canonical ensemble and investigate the effects of the dilaton field as well as other parameters on the thermal stability of the solutions. We find that there is no Hawking-Page phase transition in spite of charge provided $\\alpha \\leq \\alpha_{\\max}$.
Analytic treatment of the charged black-hole-mirror bomb in the highly explosive regime
Hod, Shahar
2013-01-01
A charged scalar field impinging upon a charged Reissner-Nordstrom black hole can be amplified as it scatters off the hole, a phenomenon known as superradiant scattering. This scattering process in the superradiant regime w>1 and for mirror radii r_m in the near-horizon region x_m=(r_m-r_+)/r_+>(tau/x_m)^2>>1 regime, which implies that the instability timescale 1/w_I of the system can be made arbitrarily short in the qQ-->infinity limit. The short instability timescale found in the linear regime along with the spherical symmetry of the system, make the charged bomb a convenient toy model for future numerical studies aimed to investigate the non-linear end-state of superradiant instabilities.
On conserved charges and thermodynamics of the AdS$_{4}$ dyonic black hole
Cárdenas, Marcela; Matulich, Javier
2016-01-01
Four-dimensional gravity in the presence of a dilatonic scalar field and an Abelian gauge field is considered. This theory corresponds to the bosonic sector of a Kaluza-Klein dimensional reduction of eleven-dimensional supergravity which induces a determined self-interacting potential for the scalar field. We compute the conserved charges and carry out the thermodynamics of an anti-de Sitter (AdS) dyonic black hole solution recently proposed. The charges coming from symmetries of the action are computed by using the Regge-Teitelboim Hamiltonian approach. These correspond to the mass, which acquires contributions from the scalar field, and the electric charge. Integrability conditions are introduced because the scalar field leads to non-integrable terms in the variation of the mass. These conditions are generically solved by introducing boundary conditions that arbitrarily relates the leading and subleading terms of the scalar field fall-off. The Hamiltonian Euclidean action, computed in the grand canonical en...
Firsova, N E
1998-01-01
We study a correct statement of the scattering problem arising for quantum charged scalar particles on the Reissner-Nordström black holes when taking into account the own electric field of black hole. The elements of the corresponding S-matrix are explored in the form convenient to physical applications and for applying numerical methods. Some further possible issues are outlined.
Jet magnetically accelerated from disk-corona around a rotating black hole
Institute of Scientific and Technical Information of China (English)
GONG XiaoLong; LI LiXin
2012-01-01
A jet acceleration model for extracting energy from disk-corona surrounding a rotating black hole (BH) is proposed.In the diskcorona scenario,we obtain the ratio of the power dissipated in the corona to the total for such disk-corona system by solving the disk dynamics equations.The analytical expression of the jet power is derived based on the electronic circuit theory of the magnetosphere.It is shown that jet power increases with the increasing BH spin,and concentrates in the inner region of the disk-corona.In addition,we use a sample consisting of 37 radio loud quasars to explore their jet production mechanism,and show that our jet formation mechanism can simulate almost all sources with high power jet,which fails to be explained by the Blandford-Znajek (BZ) process.
Coexistence of Two Mechanisms for Extracting Energy from a Rotating Black Hole
Institute of Scientific and Technical Information of China (English)
马任意; 汪定雄; 雷卫华
2003-01-01
Evolution characteristics of a rotating black hole (BH) are discussed in coexistence of the Blandford-Znajek (BZ)process and the magnetic coupling (MC) process in the parameter space consisting of the BH spin and the powerlaw index of the magnetic field on the disc. The condition for the coexistence of the two energy mechanisms are derived by using the mapping relation between the angular coordinate on the BH horizon and the radial coordinate on the disc. It is shown that not only the two mechanisms can coexist, but also the power and the rate of change of BH entropy in the BZ process will dominate over those in the MC process, provided that the BH spin and the power-law index are great enough.
Directory of Open Access Journals (Sweden)
Peter F. Newton
2012-01-01
Full Text Available The objectives of this study were to (1 quantitatively summarize the early yield responses of black spruce (Picea mariana (Mill. B.S.P. to forest vegetation management (FVM treatments through a meta-analytical review of the scientific literature, and (2 given (1, estimate the rotational consequences of these responses through model simulation. Based on a fixed-effects meta-analytic approach using 44 treated-control yield pairs derived from 12 experiments situated throughout the Great Lakes—St. Lawrence and Canadian Boreal Forest Regions, the resultant mean effect size (response ratio and associated 95% confidence interval for basal diameter, total height, stem volume, and survival responses, were respectively: 54.7% (95% confidence limits (lower/upper: 34.8/77.6, 27.3% (15.7/40.0, 198.7% (70.3/423.5, and 2.9% (−5.5/11.8. The results also indicated that early and repeated treatments will yield the largest gains in terms of mean tree size and survival. Rotational simulations indicated that FVM treatments resulted in gains in stand-level operability (e.g., reductions of 9 and 5 yr for plantations established on poor-medium and good-excellent site qualities, resp.. The challenge of maintaining coniferous forest cover on recently disturbed sites, attaining statutory-defined free-to-grow status, and ensuring long-term productivity, suggest that FVM will continue to be an essential silvicultural treatment option when managing black spruce plantations.
Gravitational field of a Schwarzschild black hole and a rotating mass ring
Sano, Yasumichi
2014-01-01
The linear perturbation of the Kerr black hole has been discussed by using the Newman--Penrose and the perturbed Weyl scalars, $\\psi_0$ and $\\psi_4$ can be obtained from the Teukolsky equation. In order to obtain the other Weyl scalars and the perturbed metric, a formalism was proposed by Chrzanowski and by Cohen and Kegeles (CCK) to construct these quantities in a radiation gauge via the Hertz potential. As a simple example of the construction of the perturbed gravitational field with this formalism, we consider the gravitational field produced by a rotating circular ring around a Schwarzschild black hole. In the CCK method, the metric is constructed in a radiation gauge via the Hertz potential, which is obtained from the solution of the Teukolsky equation. Since the solutions $\\psi_0$ and $\\psi_4$ of the Teukolsky equations are spin-2 quantities, the Hertz potential is determined up to its monopole and dipole modes. Without these lower modes, the constructed metric and Newman--Penrose Weyl scalars have unph...
On extreme transient events from rotating black holes and their gravitational wave emission
van Putten, Maurice H. P. M.; Della Valle, Massimo
2017-01-01
The super-luminous object ASASSN-15lh (SN2015L) is an extreme event with a total energy Erad ≃ 1.1 × 1052 erg in blackbody radiation on par with its kinetic energy Ek in ejecta and a late time plateau in the UV, which defies a nuclear origin. It likely presents a new explosion mechanism for hydrogen-deprived supernovae. With no radio emission and no H-rich environment, we propose to identify Erad with dissipation of a baryon-poor outflow in the optically thick remnant stellar envelope produced by a central engine. By negligible time-scales of light crossing and radiative cooling of the envelope, SN2015L's light curve closely tracks the evolution of this engine. We here model its light curve by the evolution of black hole spin during angular momentum loss in Alvén waves to matter at the Inner Most Stable Circular Orbit (ISCO). The duration is determined by σ = MT/M of the torus mass MT around the black hole of mass M: σ ˜ 10-7 and σ ˜ 10-2 for SN2015L and, respectively, a long GRB. The observed electromagnetic radiation herein represents a minor output of the rotational energy Erot of the black hole, while most is radiated unseen in gravitational radiation. This model explains the high-mass slow-spin binary progenitor of GWB150914, as the remnant of two CC-SNe in an intra-day binary of two massive stars. This model rigorously predicts a change in magnitude Δm ≃ 1.15 in the light curve post-peak, in agreement with the light curve of SN2015L with no fine-tuning.
Effects of turbulence and rotation on protostar formation as a precursor to seed black holes
Van Borm, C; Latif, M A; Schleicher, D R G; Spaans, M; Grassi, T
2014-01-01
Context. The seeds of the first supermassive black holes may result from the direct collapse of hot primordial gas in $\\gtrsim 10^4$ K haloes, forming a supermassive or quasi-star as an intermediate stage. Aims. We explore the formation of a protostar resulting from the collapse of primordial gas in the presence of a strong Lyman-Werner radiation background. Particularly, we investigate the impact of turbulence and rotation on the fragmentation behaviour of the gas cloud. We accomplish this goal by varying the initial turbulent and rotational velocities. Methods. We have performed 3D adaptive mesh refinement simulations with a resolution of 64 cells per Jeans length using the ENZO code, simulating the formation of a protostar up to unprecedented high central densities of $10^{21}$ cm$^{-3}$, and spatial scales of a few solar radii. To achieve this goal, we have employed the KROME package to improve the modelling of the chemical and thermal processes. Results. We find that the physical properties of the simula...
Lemos, José P S
2013-01-01
The analogy between sound wave propagation and light waves led to the study of acoustic holes, the acoustic analogues of black holes. Many black hole features have their counterparts in acoustic holes. The Kerr metric, the rotating metric for black holes in general relativity, has as analogue the draining bathtub metric, a metric for a rotating acoustic hole. Here we report on the progress that has been made in the understanding of features, such as quasinormal modes and tails, superresonance, and instabilities when the hole is surrounded by a reflected mirror, in the draining bathtub metric. Given then the right settings one can build up from these instabilities an apparatus that stores energy in the form of amplified sound waves. This can be put to wicked purposes as in a bomb, or to good profit as in a sonic plant.
Phase transition of charged Black Holes in Brans-Dicke theory through geometrical thermodynamics
Hendi, S. H.; Panahiyan, S.; Panah, B. Eslam; Armanfard, Z.
2016-07-01
In this paper, we take into account black hole solutions of Brans-Dicke-Maxwell theory and investigate their stability and phase transition points. We apply the concept of geometry in thermodynamics to obtain phase transition points and compare its results with those, calculated in the canonical ensemble through heat capacity. We show that these black holes enjoy second order phase transitions. We also show that there is a lower bound for the horizon radius of physical charged black holes in Brans-Dicke theory, which originates from restrictions of positivity of temperature. In addition, we find that employing a specific thermodynamical metric in the context of geometrical thermodynamics yields divergencies for the thermodynamical Ricci scalar in places of the phase transitions. It will be pointed out that due to the characteristic behavior of the thermodynamical Ricci scalar around its divergence points, one is able to distinguish the physical limitation point from the phase transitions. In addition, the free energy of these black holes will be obtained and its behavior will be investigated. It will be shown that the behavior of the free energy in the place where the heat capacity diverges demonstrates second order phase transition characteristics.
Thermodynamic instability of nonlinearly charged black holes in gravity's rainbow
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Panahiyan, S. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Panah, B.E.; Momennia, M. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2016-03-15
Motivated by the violation of Lorentz invariance in quantum gravity, we study black hole solutions in gravity's rainbow in the context of Einstein gravity coupled with various models of nonlinear electrodynamics. We regard an energy dependent spacetime and obtain the related metric functions and electric fields. We show that there is an essential singularity at the origin which is covered by an event horizon. We also compute the conserved and thermodynamical quantities and examine the validity of the first law of thermodynamics in the presence of rainbow functions. Finally, we investigate the thermal stability conditions for these black hole solutions in the context of canonical ensemble. We show that the thermodynamical structure of the solutions depends on the choices of nonlinearity parameters, charge, and energy functions. (orig.)
da Rocha, Roldao
2014-01-01
The perihelion precession, the deflection of light, and the radar echo delay are classical tests of General Relativity here used to probe brane world topologically charged black holes in a f(R) bulk and to constrain the parameter that arises from the Shiromizu-Maeda-Sasaki procedure applied to a f(R) bulk as well. The existing Solar system observational data constrain the possible values of the tidal charge parameter and the effective cosmological constant including f(R) brane world effects. We show that the observational/experimental data for both perihelion precession and radar echo delay make the black hole space of parameters to be more strict than the ones for the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) black hole geometry. Furthermore, the deflection of light constrains the tidal charge parameter similarly as the DMPR black holes due to a peculiarity in the equation of motion.
Lemos, José P. S.; Minamitsuji, Masato; Zaslavskii, Oleg B.
2017-02-01
In a (2 +1 )-dimensional spacetime with a negative cosmological constant, the thermodynamics and the entropy of an extremal rotating thin shell, i.e., an extremal rotating ring, are investigated. The outer and inner regions with respect to the shell are taken to be the Bañados-Teitelbom-Zanelli (BTZ) spacetime and the vacuum ground state anti-de Sitter spacetime, respectively. By applying the first law of thermodynamics to the extremal thin shell, one shows that the entropy of the shell is an arbitrary well-behaved function of the gravitational area A+ alone, S =S (A+). When the thin shell approaches its own gravitational radius r+ and turns into an extremal rotating BTZ black hole, it is found that the entropy of the spacetime remains such a function of A+, both when the local temperature of the shell at the gravitational radius is zero and nonzero. It is thus vindicated by this analysis that extremal black holes, here extremal BTZ black holes, have different properties from the corresponding nonextremal black holes, which have a definite entropy, the Bekenstein-Hawking entropy S (A+)=A/+4G , where G is the gravitational constant. It is argued that for extremal black holes, in particular for extremal BTZ black holes, one should set 0 ≤S (A+)≤A/+4G;i.e., the extremal black hole entropy has values in between zero and the maximum Bekenstein-Hawking entropy A/+4 G . Thus, rather than having just two entropies for extremal black holes, as previous results have debated, namely, 0 and A/+4 G , it is shown here that extremal black holes, in particular extremal BTZ black holes, may have a continuous range of entropies, limited by precisely those two entropies. Surely, the entropy that a particular extremal black hole picks must depend on past processes, notably on how it was formed. A remarkable relation between the third law of thermodynamics and the impossibility for a massive body to reach the velocity of light is also found. In addition, in the procedure, it
Charged de Sitter-like black holes: quintessence-dependent enthalpy and new extreme solutions
Energy Technology Data Exchange (ETDEWEB)
Azreg-Ainou, Mustapha [Baskent University, Faculty of Engineering, Ankara (Turkey)
2015-01-01
We consider Reissner-Nordstroem black holes surrounded by quintessence where both a non-extremal event horizon and a cosmological horizon exist besides an inner horizon (-1 ≤ ω < -1/3). We determine new extreme black hole solutions that generalize the Nariai horizon to asymptotically de Sitter-like solutions for any order relation between the squares of the charge q{sup 2} and the mass parameter M{sup 2} provided q{sup 2} remains smaller than some limit, which is larger than M{sup 2}. In the limit case q{sup 2} = 9ω{sup 2}M{sup 2}/(9ω{sup 2}-1), we derive the general expression of the extreme cosmo-blackhole, where the three horizons merge, and we discuss some of its properties.We also show that the endpoint of the evaporation process is independent of any order relation between q{sup 2} and M{sup 2}. The Teitelboim energy and the Padmanabhan energy are related by a nonlinear expression and are shown to correspond to different ensembles. We also determine the enthalpy H of the event horizon, as well as the effective thermodynamic volume which is the conjugate variable of the negative quintessential pressure, and show that in general the mass parameter and the Teitelboim energy are different from the enthalpy and internal energy; only in the cosmological case, that is, for Reissner-Nordstroem-de Sitter black hole we have H = M. Generalized Smarr formulas are also derived. It is concluded that the internal energy has a universal expression for all static charged black holes, with possibly a variable mass parameter, but it is not a suitable thermodynamic potential for static-black-hole thermodynamics if M is constant. It is also shown that the reverse isoperimetric inequality holds. We generalize the results to the case of the Reissner-Nordstroem-de Sitter black hole surrounded by quintessence with two physical constants yielding two thermodynamic volumes. (orig.)
Penrose inequalities and a positive mass theorem for charged black holes in higher dimensions
Lopes de Lima, Levi; Girão, Frederico; Lozório, Weslley; Silva, Juscelino
2016-02-01
We use the inverse mean curvature flow to establish Penrose-type inequalities for time-symmetric Einstein-Maxwell initial data sets which can be suitably embedded as a hypersurface in Euclidean space {{{R}}}n+1, n≥slant 3. In particular, we prove a positive mass theorem for this class of charged black holes. As an application, we show that the conjectured upper bound for the area in terms of the mass and the charge, which in dimension n = 3 is relevant in connection with the cosmic censorship conjecture, always holds under the natural assumption that the horizon is stable as a minimal hypersurface. The first and second authors were partially supported by CNPq/Brazil grants. The first and last authors were partially supported by a CAPES/Brazil grant.
Soto-Manriquez, Jose
2016-01-01
A new mechanism for the acceleration of ultra high energy cosmic rays (UHECR) is presented here. It is based on the tunnel-ionization of neutral atoms approaching electrically charged stellar black holes and on the repulsion of the resulting positively charged atomic part by huge, long-range electric fields. Energies above $10^{18}$ eV for these particles are calculated in a simple way by means of this single-shot, all-electrical model. When this acceleration mechanism is combined with the supernova explosions in the galactic halo of the massive runaway stars expelled from the galactic disk, this model predicts nearly the correct values of the measured top energy of the UHECRs and their flux in a specified EeV energy range. It also explains the near isotropy of the arrivals of these energetic particles to Earth, as has been recently measured by the Auger Observatory.
On a regular charged black hole with a nonlinear electric source
Culetu, Hristu
2014-01-01
A modified version of the Reissner-Nordstrom metric is proposed on the grounds of the nonlinear electrodynamics model. The source of curvature is an anisotropic fluid with $p_{r} = -\\rho$ which resembles the Maxwell stress tensor at $r >> q^{2}/2m$, where $q$ and $m$ are the mass and charge of the particle, respectively. We found the black hole horizon entropy obeys the relation $S = |W|/2T = A_{H}/4$, with $W$ the Komar energy and $A_{H}$ the horizon area. The electric field around the source depends not only on its charge but also on its mass. The corresponding electrostatic potential $\\Phi(r)$ is finite everywhere, vanishes at the origin and at $r = q^{2}/6m$ and is nonzero asymptotically, with $\\Phi_{\\infty} = 3m/2q$.
Hod, Shahar
2016-10-01
We determine the characteristic timescales associated with the linearized relaxation dynamics of the composed Reissner-Nordström-black-hole-charged-massive-scalar-field system. To that end, the quasinormal resonant frequencies {ωn(μ , q , M , Q)}n = 0 n = ∞ which characterize the dynamics of a charged scalar field of mass μ and charge coupling constant q in the charged Reissner-Nordström black-hole spacetime of mass M and electric charge Q are determined analytically in the eikonal regime 1 ≪ Mμ < qQ. Interestingly, we find that, for a given value of the dimensionless black-hole electric charge Q / M, the imaginary part of the resonant oscillation frequency is a monotonically decreasing function of the dimensionless ratio μ / q. In particular, it is shown that the quasinormal resonance spectrum is characterized by the asymptotic behavior ℑ ω → 0 in the limiting case Mμ → qQ. This intriguing finding implies that the composed Reissner-Nordström-black-hole-charged-massive-scalar-field system is characterized by extremely long relaxation times τrelax ≡ 1 / ℑ ω → ∞ in the Mμ / qQ →1- limit.
Directory of Open Access Journals (Sweden)
Shahar Hod
2016-10-01
Full Text Available We determine the characteristic timescales associated with the linearized relaxation dynamics of the composed Reissner–Nordström-black-hole-charged-massive-scalar-field system. To that end, the quasinormal resonant frequencies {ωn(μ,q,M,Q}n=0n=∞ which characterize the dynamics of a charged scalar field of mass μ and charge coupling constant q in the charged Reissner–Nordström black-hole spacetime of mass M and electric charge Q are determined analytically in the eikonal regime 1≪Mμ
Shatskiy, A A; Lipatova, L N
2013-01-01
The free fall of electric charges and dipoles, radial and freely falling into the Schwarzschild black hole event horizon, was considered. Inverse effect of electromagnetic fields on the black hole is neglected. Dipole was considered as a point particle, so the deformation associated with exposure by tidal forces are neglected. According to the theorem, "the lack of hair" of black holes, multipole magnetic fields must be fully emitted by multipole fall into a black hole. The spectrum of electromagnetic radiation power for these multipoles (monopole and dipole) was found. Differences were found in the spectra for different orientations of the falling dipole. A general method has been developed to find radiated electromagnetic multipole fields for the free falling multipoles into a black hole (including higher order multipoles - quadrupoles, etc.). The electromagnetic spectrum can be compared with observational data from stellar mass and smaller black holes.
Critical behavior of charged Gauss-Bonnet AdS black holes in the grand canonical ensemble
Zou, De-Cheng; Wang, Bin
2014-01-01
We study the thermodynamics in the grand canonical ensemble of D-dimensional charged Gauss-Bonnet-AdS black holes in the extended phase space. We find that the usual small-large black hole phase transition, which exhibits analogy with the Van de Waals liquid-gas system holds in five-dimensional spherical charged Gauss-Bonnet-AdS black holes when its potential is fixed within the range $0<\\Phi<\\frac{\\sqrt{3}\\pi}{4}$. For the other higher dimensional and topological charged Gauss-Bonnet-AdS black holes, there is no such phase transition. In the limiting case, Reissner-Nordstrom-AdS black holes, with vanishing Gauss-Bonnet parameter, there is no critical behavior in the grand canonical ensemble. This result holds independent of the spacetime dimensions and topologies. We also examine the behavior of physical quantities in the vicinity of the critical point in the five-dimensional spherical charged Gauss-Bonnet-AdS black holes.
Renormalized stress-energy tensor near the horizon of a slowly evolving, rotating black hole
Frolov, Valery P.; Thorne, Kip S.
1989-04-01
The renormalized expectation value of the stress-energy tensor ren of a quantum field in an arbitrary quantum state near the future horizon of a rotating (Kerr) black hole is derived in two very different ways: One derivation (restricted for simplicity to a massless scalar field) makes use of traditional techniques of quantum field theory in curved spacetime, augmented by a variant of the ``η formalism'' for handling superradiant modes. The other derivation (valid for any quantum field) uses the equivalence principle to infer, from ren in flat spacetime, what must be ren near the hole's horizon. The two derivations give the same result-a result in accord with a previous conjecture by Zurek and Thorne: ren, in any quantum state, is equal to that, ZAMO, which zero-angular-momentum observers (ZAMO's) would compute from their own physical measurements near the horizon, plus a vacuum-polarization contribution Tvac polμν, which is the negative of the stress-energy of a rigidly rotating thermal reservoir with angular velocity equal to that of the horizon ΩH, and (red-shifted) temperature equal to that of the Hawking temperature TH. A discussion of the conditions of validity for equivalence-principle arguments reveals that curvature-coupling effects (of which the equivalence principle is unaware) should produce fractional corrections of order α2≡(surface gravity of hole)2×(distance to horizon)2 to Tvac polμν and since gravitational blue-shifts cause the largest components of Tvac polμν in the proper reference frame of the ZAMO's to be of O(α-2), curvature-coupling effects in Tvac polμν and thence in ren are of O(α0) in the ZAMO frame. It is shown, by a quantum-field-theory derivation of the density matrix, that in the Hartle-Hawking vacuum the near-horizon ZAMO's see a thermal reservoir with angular velocity ΩH and temperature TH whose thermal stress-energy ZAMO gets renormalized away by Tvac polμν, annulling the O(α-2) and O(α-1) pieces of ren, and
On the construction of charged operators inside an eternal black hole
Guica, Monica
2015-01-01
We revisit the holographic construction of (approximately) local bulk operators inside an eternal AdS black hole in terms of operators in the boundary CFTs. If the bulk operator carries charge, the construction must involve a qualitatively new object: a Wilson line that stretches between the two boundaries of the eternal black hole. This operator - more precisely, its zero mode - cannot be expressed in terms of the boundary currents and only exists in entangled states dual to two-sided geometries, which suggests that it is a state-dependent operator. We determine the action of the Wilson line on the relevant subspaces of the total Hilbert space, and show that it behaves as a local operator from the point of view of either CFT. For the case of three bulk dimensions, we give explicit expressions for the charged bulk field and the Wilson line. Furthermore, we show that when acting on the thermofield double state, the Wilson line may be extracted from a limit of certain standard CFT operator expressions. We also ...
Energy Technology Data Exchange (ETDEWEB)
Li, Jin [Chongqing University, Department of Physics, Chongqing (China); Lin, Kai [Universidade de Sao Paulo, Instituto de Fisica, CP 66318, Sao Paulo (Brazil); Yang, Nan [Huazhong University of Science and Technology, Department of Physics, Wuhan (China)
2015-03-01
Based on a regular exact black hole (BH) from nonlinear electrodynamics (NLED) coupled to general relativity, we investigate the stability of such BH through the Quasinormal Modes (QNMs) of electromagnetic (EM) field perturbations and its thermodynamics through Hawking radiation. In perturbation theory, we can deduce the effective potential from a nonlinear EM field. The comparison of the potential function between regular and RN BHs could predict similar QNMs. The QNM frequencies tell us the effect of the magnetic charge q, the overtone n, and the angular momentum number l on the dynamic evolution of NLED EM field. Furthermore we also discuss the cases of near-extreme conditions of such a magnetically charged regular BH. The corresponding QNM spectrum illuminates some special properties in the near-extreme cases. For the thermodynamics, we employ the Hamilton-Jacobi method to calculate the near-horizon Hawking temperature of the regular BH and reveal the relationship between the classical parameters of the black hole and its quantum effects. (orig.)
Charged de Sitter-like black holes: quintessence-dependent enthalpy and new extreme solutions
Azreg-Aïnou, Mustapha
2014-01-01
We consider Reissner-Nordstr\\"om black holes surrounded by quintessence where both a non-extremal event horizon and a cosmological horizon exist besides an inner horizon ($-1\\leq \\om <-1/3$). We determine new extreme black hole solutions that generalize the Nariai horizon to asymptotically de Sitter-like solutions for any order relation between the squares of the charge $q^2$ and the mass parameter $M^2$ provided $q^2$ remains smaller than some limit, which is larger than $M^2$. In the limit case $q^2=9\\om^2 M^2/(9\\om^2-1)$, we derive the general expression of the extreme cosmo-black-hole, where the three horizons merge, and discuss some of its properties. We also show that the endpoint of the evaporation process is independent of any order relation between $q^2$ and $M^2$. The Teitelboim's energy and Padmanabhan's energy are related by a nonlinear expression and are shown to correspond to different ensembles. We also determine the enthalpy $H$ of the event horizon, as well as the effective thermodynamic v...
Quasinormal Modes of Charged Dilaton Black Holes and Their Entropy Spectra
Sakalli, I.
2013-08-01
In this study, we employ the scalar perturbations of the charged dilaton black hole (CDBH) found by Chan, Horne and Mann (CHM), and described with an action which emerges in the low-energy limit of the string theory. A CDBH is neither asymptotically flat (AF) nor non-asymptotically flat (NAF) spacetime. Depending on the value of its dilaton parameter a, it has both Schwarzschild and linear dilaton black hole (LDBH) limits. We compute the complex frequencies of the quasinormal modes (QNMs) of the CDBH by considering small perturbations around its horizon. By using the highly damped QNM in the process prescribed by Maggiore, we obtain the quantum entropy and area spectra of these black holes (BHs). Although the QNM frequencies are tuned by a, we show that the quantum spectra do not depend on a, and they are equally spaced. On the other hand, the obtained value of undetermined dimensionless constant ɛ is the double of Bekenstein's result. The possible reason of this discrepancy is also discussed.
Numerical study of the gravitational shock wave inside a spherical charged black hole
Eilon, Ehud; Ori, Amos
2016-11-01
We numerically investigate the interior of a four-dimensional, asymptotically flat, spherically symmetric charged black hole perturbed by a scalar field Φ . Previous study by Marolf and Ori indicated that late infalling observers will encounter an effective shock wave as they approach the left portion of the inner horizon. This shock manifests itself as a sudden change in the values of various fields, within a tremendously short interval of proper time τ of the infalling observers. We confirm this prediction numerically for both test and self-gravitating scalar-field perturbations. In both cases we demonstrate the effective shock in the scalar field by exploring Φ (τ ) along a family of infalling timelike geodesics. In the self-gravitating case we also demonstrate the shock in the area coordinate r by exploring r (τ ). We confirm the theoretical prediction concerning the shock sharpening rate, which is exponential in the time of infall into the black hole. In addition we numerically probe the early stages of shock formation. We also employ a family of null (rather than timelike) ingoing geodesics to probe the shock in r . We use a finite-difference numerical code with double-null coordinates combined with a recently developed adaptive gauge method in order to solve the (Einstein+scalar ) field equations and to evolve the spacetime (and scalar field)—from the region outside the black hole down to the vicinity of the Cauchy horizon and the spacelike r =0 singularity.
Hod, Shahar
2016-01-01
We determine the characteristic timescales associated with the linearized relaxation dynamics of the composed Reissner-Nordstr\\"om-black-hole-charged-massive-scalar-field system. To that end, the quasinormal resonant frequencies $\\{\\omega_n(\\mu,q,M,Q)\\}_{n=0}^{n=\\infty}$ which characterize the dynamics of a charged scalar field of mass $\\mu$ and charge coupling constant $q$ in the charged Reissner-Nordstr\\"om black-hole spacetime of mass $M$ and electric charge $Q$ are determined {\\it analytically} in the eikonal regime $1\\ll M\\mu
Fiacconi, Davide; Rossi, Elena M.
2017-01-01
Supermassive black holes are a key ingredient of galaxy evolution. However, their origin is still highly debated. In one of the leading formation scenarios, a black hole of ˜100 M⊙ results from the collapse of the inner core of a supermassive star (≳104-5 M⊙), created by the rapid accumulation (≳0.1 M⊙ yr-1) of pristine gas at the centre of newly formed galaxies at z ˜ 15. The subsequent evolution is still speculative: the remaining gas in the supermassive star can either directly plunge into the nascent black hole or part of it can form a central accretion disc, whose luminosity sustains a surrounding, massive, and nearly hydrostatic envelope (a system called a `quasi-star'). To address this point, we consider the effect of rotation on a quasi-star, as angular momentum is inevitably transported towards the galactic nucleus by the accumulating gas. Using a model for the internal redistribution of angular momentum that qualitatively matches results from simulations of rotating convective stellar envelopes, we show that quasi-stars with an envelope mass greater than a few 105 M_{⊙} × (black hole mass/100 M_{⊙})^{0.82} have highly sub-Keplerian gas motion in their core, preventing gas circularization outside the black hole's horizon. Less massive quasi-stars could form but last for only ≲104 yr before the accretion luminosity unbinds the envelope, suppressing the black hole growth. We speculate that this might eventually lead to a dual black hole seed population: (i) massive (>104 M⊙) seeds formed in the most massive (>108 M⊙) and rare haloes; (ii) lighter (˜102 M⊙) seeds to be found in less massive and therefore more common haloes.
Fiacconi, Davide; Rossi, Elena M.
2016-10-01
Supermassive black holes are a key ingredient of galaxy evolution. However, their origin is still highly debated. In one of the leading formation scenarios, a black hole of ˜100 M⊙ results from the collapse of the inner core of a supermassive star (≳ 104 - 5 M⊙), created by the rapid accumulation (≳ 0.1 M⊙ yr-1) of pristine gas at the centre of newly formed galaxies at z ˜ 15. The subsequent evolution is still speculative: the remaining gas in the supermassive star can either directly plunge into the nascent black hole, or part of it can form a central accretion disc, whose luminosity sustains a surrounding, massive, and nearly hydrostatic envelope (a system called a "quasi-star"). To address this point, we consider the effect of rotation on a quasi-star, as angular momentum is inevitably transported towards the galactic nucleus by the accumulating gas. Using a model for the internal redistribution of angular momentum that qualitative matches results from simulations of rotating convective stellar envelopes, we show that quasi-stars with an envelope mass greater than a few 105 M⊙ × black hole mass/100 M⊙)0.82 have highly sub-keplerian gas motion in their core, preventing gas circularisation outside the black hole's horizon. Less massive quasi-stars could form but last for only ≲ 104 years before the accretion luminosity unbinds the envelope, suppressing the black hole growth. We speculate that this might eventually lead to a dual black hole seed population: (i) massive (>104 M⊙) seeds formed in the most massive (>108 M⊙) and rare haloes; (ii) lighter (˜102 M⊙) seeds to be found in less massive and therefore more common haloes.
Rasskazov, Alexander
2016-01-01
We compute the isotropic gravitational wave (GW) background produced by binary supermassive black holes (SBHs) in galactic nuclei. In our model, massive binaries evolve at early times via gravitational-slingshot interaction with nearby stars, and at later times by the emission of GWs. Our expressions for the rate of binary hardening in the "stellar" regime are taken from the recent work of Vasiliev et al., who show that in the non-axisymmetric galaxies expected to form via mergers, stars are supplied to the center at high enough rates to ensure binary coalescence on Gyr timescales. We also include, for the first time, the extra degrees of freedom associated with evolution of the binary's orbital plane; in rotating nuclei, interaction with stars causes the orientation and the eccentricity of a massive binary to change in tandem, leading in some cases to very high eccentricities (e>0.9) before the binary enters the GW-dominated regime. We argue that previous studies have over-estimated the mean ratio of SBH mas...
Miskovic, Olivera
2010-01-01
Motivated by possible applications within the framework of anti-de Sitter gravity/Conformal Field Theory (AdS/CFT) correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by a nonlinear electrodynamics (NED) are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary NED Lagrangian, in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, it extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Fall-off conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass...
Institute of Scientific and Technical Information of China (English)
ZHAO Wei-Qin; LEI Jie-Hong; LIU Zhi-Xiang; YANG Shu-Zheng
2008-01-01
Extending the Parikh's quantum tunneling method of an uncharged particle, we investigate the quantum radiation characteristics of a particle with electric and magnetic charge via tunneling from the event horizon of theKerr-Newman-Kasuya black hole. The derived result supports the Parikh's opinion and the correction to the thermal spectrum is of precisely the form that satisfies the underlying unitary quantum theory, and finally provides a might explanation to the black hole information puzzle.
Area spectrum of the d-dimensional Reissner-Nordstroem black hole in the small charge limit
Energy Technology Data Exchange (ETDEWEB)
Lopez-Ortega, A, E-mail: alopezo@ipn.mx [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada, Unidad Legaria, Instituto Politecnico Nacional, Calzada Legaria 694, Colonia Irrigacion, Delegacion Miguel Hidalgo, Mexico, D F, C P 11500 (Mexico)
2011-02-07
A conjecture by Hod states that for the black hole horizon the spacing of its area spectrum is determined by the asymptotic value of its quasinormal frequencies. Recently to overcome some difficulties, Maggiore proposes some changes to the original Hod's conjecture. Taking into account the modifications proposed by Maggiore we calculate the area quantum of the d-dimensional Reissner-Nordstroem black hole in the small charge limit.
Black holes under external inﬂuence
Indian Academy of Sciences (India)
Jiří Bičák
2000-10-01
The work on black holes immersed in external ﬁelds is reviewed in both test-ﬁeld approximation and within exact solutions. In particular we pay attention to the effect of the expulsion of the ﬂux of external ﬁelds across charged and rotating black holes which are approaching extremal states. Recently this effect has been shown to occur for black hole solutions in string theory. We also discuss black holes surrounded by rings and disks and rotating black holes accelerated by strings.
Charge Expulsion from Black Brane Horizons, and Holographic Quantum Criticality in the Plane
D'Hoker, Eric
2012-01-01
Quantum critical behavior in 2+1 dimensions is established via holographic methods in a 5+1-dimensional Einstein gravity theory with gauge potential form fields of rank 1 and 2. These fields are coupled to one another via a tri-linear Chern-Simons term with strength k. The quantum phase transition is physically driven by the expulsion of the electric charge from inside the black brane horizon to the outside, where it gets carried by the gauge fields which acquire charge thanks to the Chern-Simons interaction. At a critical value k=k_c, zero temperature, and any finite value of the magnetic field, the IR behavior is governed by a near-horizon Lifshitz geometry. The associated dynamical scaling exponent depends on the magnetic field. For k k_c, the IR flow is towards the purely magnetic brane in AdS_6. Its near-horizon geometry is AdS_4 \\times R^2, so that the entropy density vanishes quadratically with temperature, and all charge is carried by the gauge fields outside of the horizon.
Institute of Scientific and Technical Information of China (English)
LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng
2008-01-01
Using anomalous viewpoint,we study the Hawking radiation from a kind of topological Kerr Anti-de-Sitter(Kerr AdS)black hole with ode rotational parameter.We employ the covariant gauge and gravitational anomalies.The result supports the Robinson-Wilczek opinion and shows that the Hawking temperature can be correctly determined by cancelling covariant gauge and gravitational anomalies at the horizon.
$P-V$ Criticality In the Extended Phase Space of Charged Accelerating AdS Black Holes
Liu, Hang
2016-01-01
In this paper, we investigate the $P-V$ criticality and phase transition of charged accelerating AdS black holes in the extended thermodynamic phase space in analogy between black hole system and Van der Waals liquid-gas system, where the cosmological constant $\\Lambda$ is treated as a thermodynamical variable interpreted as dynamic pressure and its conjugate quantity is the thermodynamic volume of the black holes. When the electric charge vanishes, we find that no $P-V$ criticality will appear but the Hawking-Page like phase transition will be present, just as what Schwarzschild-AdS black holes behave like. For the charged case, the $P-V$ criticality appears and the accelerating black holes will undergo a small black hole/large phase transition under the condition that the acceleration parameter $A$ and the horizon radius $r_h$ meet a certain simple relation $A r_h=a$, where $a$ is a constant in our discussion. To make $P-V$ criticality appear, there exists an upper bounds for constant $a$. When $P-V$ critic...
P-V criticality in the extended phase-space of charged accelerating AdS black holes
Liu, Hang; Meng, Xin-He
2016-11-01
In this paper, we investigate the P-V criticality and phase transition of charged accelerating AdS black holes in the extended thermodynamic phase-space in analogy between black hole system and van der Waals liquid-gas system, where the cosmological constant Λ is treated as a thermodynamical variable interpreted as dynamic pressure and its conjugate quantity is the thermodynamic volume of the black holes. When the electric charge vanishes, we find that no P-V criticality will appear but the Hawking-Page-like phase transition will be present, just as what Schwarzschild-AdS black holes behave like. For the charged case, the P-V criticality appears and the accelerating black holes will undergo a small black hole/large phase transition under the condition that the acceleration parameter A and the horizon radius rh meet a certain simple relation Arh = a, where a is a constant in our discussion. To make P-V criticality appear, there exists an upper bounds for constant a. When P-V criticality appears, we calculate the critical pressure Pc, critical temperature Tc and critical specific volume rc, and we find that Pcrc Tc is an universal number.
Konoplya, R. A.; Zhidenko, A.
2014-01-01
In our earlier work [Phys. Rev. Lett. 103, 161101 (2009)], it was shown that nonextremal highly charged Reissner-Nordstrøm-de Sitter black holes are gravitationally unstable in D>6-dimensional space-times. Here, we find accurate threshold values of the Λ term at which the instability of the extremally charged black holes starts. The larger D is, the smaller is the threshold value of Λ. We have shown that the ratio ρ =rh/rcos (where rcos and rh are the cosmological and event horizons) is proportional to e-(D -4)/2 at the onset of instability for D=7,8,…11, implying that the same law should fulfill for arbitrary D. This is numerical evidence that extremally charged Reissner-Nordstrøm-de Sitter black holes are gravitationally unstable for D>6, while asymptotically flat extremally charged Reissner-Nordstrøm black holes are stable for all D. The instability is not connected to the horizon instability discussed recently in the literature, and, unlike the later one, develops also outside the event horizon; that is, it can be seen by an external observer. In addition, for the nonextremal case through fitting of the numerical data, we obtained an approximate analytical formula which relates values of charge and the Λ term at the onset of instability.
Black Ring with a Positive Cosmological Constant
Chu, C S; Chu, Chong-Sun; Dai, Shou-Huang
2007-01-01
We construct a black ring with a cosmological constant in the five dimensional N=4 de Sitter supergravity theory. The black ring preserves half of the de Sitter supersymmetries. Unlike the flat case, this black ring is not rotating and the stability against gravitational self-attraction is balanced by the cosmological repulsion due to the cosmological constant. The black ring carries a dipole charge and this charge contributes to the first law of thermodynamics. The black ring has an entropy and mass which conform to the entropic N-bound proposal and the maximal mass conjecture.
Directory of Open Access Journals (Sweden)
Amin Dehyadegari
2017-05-01
Full Text Available It has been argued that charged Anti-de Sitter (AdS black holes have similar thermodynamic behavior as the Van der Waals fluid system, provided one treats the cosmological constant as a thermodynamic variable (pressure in an extended phase space. In this paper, we disclose the deep connection between charged AdS black holes and Van der Waals fluid system from an alternative point of view. We consider the mass of an AdS black hole as a function of square of the charge Q2 instead of the standard Q, i.e. M=M(S,Q2,P. We first justify such a change of view mathematically and then ask if a phase transition can occur as a function of Q2 for fixed P. Therefore, we write the equation of state as Q2=Q2(T,Ψ where Ψ (conjugate of Q2 is the inverse of the specific volume, Ψ=1/v. This allows us to complete the analogy of charged AdS black holes with Van der Waals fluid system and derive the phase transition as well as critical exponents of the system. We identify a thermodynamic instability in this new picture with real analogy to Van der Waals fluid with physically relevant Maxwell construction. We therefore study the critical behavior of isotherms in Q2–Ψ diagram and deduce all the critical exponents of the system and determine that the system exhibits a small–large black hole phase transition at the critical point (Tc,Qc2,Ψc. This alternative view is important as one can imagine such a change for a given single black hole i.e. acquiring charge which induces the phase transition. Finally, we disclose the microscopic properties of charged AdS black holes by using thermodynamic geometry. Interestingly, we find that scalar curvature has a gap between small and large black holes, and this gap becomes exceedingly large as one moves away from the critical point along the transition line. Therefore, we are able to attribute the sudden enlargement of the black hole to the strong repulsive nature of the internal constituents at the phase transition.
Zakharov, Alexander F
2014-01-01
Using an algebraic condition of vanishing discriminant for multiple roots of fourth degree polynomials we derive an analytical expression of a shadow size as a function of a charge in the Reissner -- Nordstr\\"om (RN) metric \\cite{Reissner_16,Nordstrom_18}. We consider shadows for negative tidal charges and charges corresponding to naked singularities $q=\\mathcal{Q}^2/M^2 > 1$, where $\\mathcal{Q}$ and $M$ are black hole charge and mass, respectively, with the derived expression. An introduction of a negative tidal charge $q$ can describe black hole solutions in theories with extra dimensions, so following the approach we consider an opportunity to extend RN metric to negative $\\mathcal{Q}^2$, while for the standard RN metric $\\mathcal{Q}^2$ is always non-negative. We found that for $q > 9/8$ black hole shadows disappear. Significant tidal charges $q=-6.4$ (suggested by Bin-Nun (2010)) are not consistent with observations of a minimal spot size at the Galactic Center observed in mm-band, moreover, these observa...
Quasinormal modes of charged dilaton black holes and their entropy spectra
Sakalli, I
2013-01-01
In this study, we employ the scalar perturbations of the charged dilaton black hole (CDBH) found by Chan, Horne and Mann (CHM), and described with an action which emerges in the low-energy limit of the string theory. A CDBH is neither asymptotically flat (AF) nor non-asymptotically flat (NAF) spacetime. Depending on the value of its dilaton parameter "a", it has both Schwarzschild and linear dilaton black hole (LDBH) limits. We compute the complex frequencies of the quasinormal modes (QNM) of the CDBH by considering small perturbations around its horizon. By using the highly damped QNMs in the process prescribed by Maggiore, we obtain the quantum entropy and area spectra of these BHs. Although the QNM frequencies are tuned by "a", we show that the quantum spectra do not depend on "a", and they are equally spaced. On the other hand, the obtained value of undetermined dimensionless constant {\\epsilon} is the double of Bekenstein's result. The possible reason of this discrepancy is also discussed.
Numerical study of the gravitational shock wave inside a spherical charged black hole
Eilon, Ehud
2016-01-01
We numerically investigate the interior of a four-dimensional, asymptotically flat, spherically symmetric charged black hole perturbed by a scalar field $\\Phi$. Previous study by Marolf and Ori indicated that late infalling observers will encounter an effective shock wave as they approach the left portion of the inner horizon. This shock manifests itself as a sudden change in the values of various fields, within a tremendously short interval of proper time $\\tau$ of the infalling observers. We confirm this prediction numerically for both test and self-gravitating scalar field perturbations. In both cases we demonstrate the effective shock in the scalar field by exploring $\\Phi(\\tau)$ along a family of infalling timelike geodesics. In the self-gravitating case we also demonstrate the shock in the area coordinate $r$ by exploring $r(\\tau)$. We confirm the theoretical prediction concerning the shock sharpening rate, which is exponential in the time of infall into the black hole. In addition we numerically probe ...
The self-force on a non-minimally coupled static scalar charge outside a Schwarzschild black hole
Energy Technology Data Exchange (ETDEWEB)
Cho, Demian H J; Tsokaros, Antonios A; Wiseman, Alan G [Department of Physics, University of Wisconsin-Milwaukee, PO Box 413, Milwaukee, WI 53201 (United States)
2007-03-07
The finite part of the self-force on a static, non-minimally coupled scalar test charge outside a Schwarzschild black hole is zero. This result is determined from the work required to slowly raise or lower the charge through an infinitesimal distance. Unlike similar force calculations for minimally-coupled scalar charges or electric charges, we find that we must account for a flux of field energy that passes through the horizon and changes the mass and area of the black hole when the charge is displaced. This occurs even for an arbitrarily slow displacement of the non-minimally coupled scalar charge. For a positive coupling constant, the area of the hole increases when the charge is lowered and decreases when the charge is raised. The fact that the self-force vanishes for a static, non-minimally coupled scalar charge in Schwarzschild spacetime agrees with a simple prediction of the Quinn-Wald axioms. However, Zel'nikov and Frolov computed a non-vanishing self-force for a non-minimally coupled charge. Our method of calculation closely parallels the derivation of Zel'nikov and Frolov, and we show that their omission of this unusual flux is responsible for their (incorrect) result. When the flux is accounted for, the self-force vanishes. This correction eliminates a potential counter example to the Quinn-Wald axioms. The fact that the area of the black hole changes when the charge is displaced brings up two interesting questions that did not arise in similar calculations for static electric charges and minimally coupled scalar charges. (1) How can we reconcile a decrease in the area of the black hole horizon with the area theorem which concludes that {delta}Area{sub horizon} {>=} 0? The key hypothesis of the area theorem is that the stress-energy tensor must satisfy a null-energy condition T{sup {alpha}}{sup {beta}}l{sub {alpha}}l{sub {beta}} {>=} 0 for any null vector l{sub {alpha}}. We explicitly show that the stress-energy associated with a non
Institute of Scientific and Technical Information of China (English)
XU Dian-Yah
2000-01-01
Absorbing charged rotating (ACR) metric in de Sitter space and related energy-momentum tensor are derived.The ACR metric is very simple in advanced time coordinates. The ACR metric involves 8 independent parameters which are divided into two classes: (1) the mass M, charge Q, angular momentum per unit mass a, and cosmological constant A; (2) M/ v, 2M/ v2, Q/ v, and 2Q/ v2. The non-stationary part of the energy-momentum tensor is positive definite everywhere.
Energy Technology Data Exchange (ETDEWEB)
Stettler, R.F.; Hinckley, T.M. [Washington Univ., Seattle, WA (United States). Coll. of Forest Resources; Heilman, P.E. [Washington State Univ., Puyallup, WA (United States). Research and Extension Center; Bradshaw, H.D. Jr. [Washington Univ., Seattle, WA (United States). Dept. of Biochemistry
1993-04-30
This project was initiated in 1978 to serve three objectives: (1) develop genetically improved poplar cultivars offering increased productivity under short-rotation culture; (2) identify the major components of productivity in poplar and determine ways in which they can be manipulated, genetically and culturally; and (3) engage in technology transfer to regional industry and agencies so as to make poplar culture in the Pacific Northwest economically feasible. The project is aimed at capturing natural variation in the native black cottonwood. Populus trichocarpa T & G, and enhancing it through selective breeding. Major emphasis has been placed on hybridization of black cottonwood with P deltoides and P maximowiczii, more recently with p nigra. First-generation (F{sub 1}) hybrids have consistently outperformed black cottonwood by a factor of 1.5.-2. The high yields of woody biomass obtained from these clonally propagated hybrids, in rotations of 4-7 years, have fostered the establishment of large-scale plantations by the pulp and paper industry in the region. Physiological studies have helped to elucidate hybrid superiority and several of the underlying mechanisms.
Veste, M.; Böhm, C.; Quinckenstein, A.; Freese, D.
2012-04-01
The importance of short rotation forests and agroforestry systems for woody biomass production for bioenergy will increase in Central Europe within the next decades. In this context, black locust (Robinia pseudoacacia) has a high growth potential especially at marginal, drought-susceptible sites such as occur in Brandenburg State (Eastern Germany). As a pioneer tree species black locust grows under a wide range of site conditions. The native range of black locust in Northern America is classified by a humid to sub-humid climate with a mean annual precipitation of 1020 to 1830 mm. In Central and Eastern Europe, this species is cultivated in a more continental climate with an annual precipitation often below 600 mm. Therefore, black locust is known to be relatively drought tolerant compared to other temperate, deciduous tree species. Because of its N2-fixation ability black locust plays generally an important role for the improvement of soil fertility. This effect is of particular interest at marginal sites in the post-mining landscapes. In order to estimate the N2-fixation potential of black locust at marginal sites leaf samples were taken from black locust trees in short rotation plantations planted between 1995 and 2007 in post-mining sites south of Cottbus (Brandenburg, NE Germany). The variation of the natural 15N abundance was measured to evaluate the biological nitrogen fixation. The nitrogen derived from the atmosphere can be calculated using a two-pool model from the quotient of the natural 15N abundances of the N2-fixing plant and the plant available soil N. Because representatively determining the plant available soil N is difficult, a non-N2-fixing reference plant growing at the same site with a similar root system and temporal N uptake pattern to the N2-fixing plant is often used. In our case we used red oak (Quercus rubra) as a reference. The average nitrogen content in the leaves of black locust ranged from 3.1% (C/N 14.8) in 15 years old trees to 3
Brown, J D; York, James W.
1993-01-01
The authors have recently proposed a "microcanonical functional integral" representation of the density of quantum states of the gravitational field. The phase of this real-time functional integral is determined by a "microcanonical" or Jacobi action, the extrema of which are classical solutions at fixed total energy, not at fixed total time interval as in Hamilton's action. This approach is fully general but is especially well suited to gravitating systems because for them the total energy can be fixed simply as a boundary condition on the gravitational field. In this paper we describe how to obtain Jacobi's action for general relativity. We evaluate it for a certain complex metric associated with a rotating black hole and discuss the relation of the result to the density of states and to the entropy of the black hole.
Institute of Scientific and Technical Information of China (English)
GONG Xiao-Long; WANG Ding-Xiong
2005-01-01
@@ We discuss jet production from an advection dominated accretion flow (ADAF) around a rotating black hole (BH) in an electromagnetic regime. An analytical expression for the jet power is derived by using an equivalent circuit in the BH magnetosphere. It turns out that a large fraction of jet powers is contributed from the inner region of the ADAF, and the jet power depends sensitively on the degree to which the flow is advection-dominated. In addition, we use our model to fit the strong jet powers of several BL Lac objects, which cannot be explained by virtue of the BZ process.
Energy Technology Data Exchange (ETDEWEB)
Wright, L.L.; Perlack, R.D.; Wenzel, C.R.; Trimble, J.L.; Ranney, J.W.
1985-08-01
This report covers the progress of the Short Rotation Woody Crops Program (SRWCP) during the third quarter of fiscal year 1985. This report summarizes ORNL management activities, technical activities at ORNL and subcontract institutions, and the technology transfer that is occurring as a result of subcontractor and ORNL activities. Third-year results of a nutrient utilization study confirmed that there were no benefits to quarterly fertilization with urea nitrogen. Testing of one prototype short-rotation intensive culture harvester was conducted on a sycamore plantation on Scott Paper Company land in southern Alabama. Coppice yields of European black alder reported by Iowa State University indicate potential productivity of about 7.2 dry Mg . ha/sup -1/ . year/sup -1/ if the best trees are selected. Coppice yields were more than double first-rotation yields. About 31,000 black locust and larch trees were established in 12 genetic tests at 4 sites in Michigan. Seedling rotation productivity rates of 4-year-old hybrid poplar, based on harvest data, were reported by Pennsylvania State University. Rates varied from 4.8 dry Mg . ha/sup -1/ . year/sup -1/ to 10.7 dry Mg . ha/sup -1/ . year/sup -1/, depending on site, management strategy, and planting year. An efficient method for in vitro micropropagation of elite genotypes of fourwing saltbush was developed by Plant Resources Institute. A new study to evaluate yield/density relationships was established by the USDA Forest Service, Pacific Northwest Forest and Range Experiment Station. Dissertation research on the crown geometry of plantation-grown American sycamore was completed.
Jusufi, Kimet
2016-01-01
In this paper we study the quantum tunneling of charged and magnetized particles (magnetic monopoles) from the global monopole black hole by incorporating the quantum gravity effects. Starting from the modified Maxwell's equations and Generalized Uncertainty Relation (GUP), we recover the GUP corrected temperate for the global monopole black hole by solving the modified Dirac equation via Hamilton-Jacobi method. Furthermore, we also include the quantum corrections beyond the semiclassical approximation, in particular, first we find the logarithmic corrections of GUP corrected entropy and finally we calculate the GUP corrected specific heat capacity.
Institute of Scientific and Technical Information of China (English)
ZHANG Hong-Bao; CAO Zhou-Jian; GAO Chong-Shou
2004-01-01
Si-Jie Gao has recently investigated Hawking radiation from spherically symmetrical gravitational collapse to an extremal R-N black hole for a real scalar field. Especially he estimated the upper bound for the expected number of particles in any wave packet belonging to Hout spontaneously produced from the state |0＞in, which confirms the traditional belief that extremal black holes do not radiate particles. Making some modifications, we demonstrate that the analysis can go through for a charged scalar field.
Kuo, C Y; Rao, R; Nakamura, M; Algaba, J C; Liu, H B; Inoue, M; Koch, P M; Ho, P T P; Matsushita, S; Pu, H -Y; Akiyama, K; Nishioka, H; Pradel, N
2014-01-01
We present the first constraint on Faraday rotation measure (RM) at submillimeter wavelengths for the nucleus of M 87. By fitting the polarization position angles ($\\chi$) observed with the SMA at four independent frequencies around $\\sim$230 GHz and interpreting the change in $\\chi$ as a result of \\emph{external} Faraday rotation associated with accretion flow, we determine the rotation measure of the M 87 core to be between $-$7.5$\\times$10$^{5}$ and 3.4$\\times$10$^{5}$ rad/m$^{2}$. Assuming a density profile of the accretion flow that follows a power-law distribution and a magnetic field that is ordered, radial, and has equipartition strength, the limit on the rotation measure constrains the mass accretion rate $\\dot{M}$ to be below 9.2$\\times$10$^{-4}$ M$_{\\odot}$~yr$^{-1}$ at a distance of 21 Schwarzchild radii from the central black hole. This value is at least two orders of magnitude smaller than the Bondi accretion rate, suggesting significant suppression of the accretion rate in the inner region of t...
Directory of Open Access Journals (Sweden)
Shahar Hod
2015-07-01
Full Text Available The quasinormal resonance spectrum {ωn(μ,q,M,Q}n=0n=∞ of charged massive scalar fields in the charged Reissner–Nordström black-hole spacetime is studied analytically in the large-coupling regime qQ≫Mμ (here {μ,q} are respectively the mass and charge coupling constant of the field, and {M,Q} are respectively the mass and electric charge of the black hole. This physical system provides a striking illustration for the validity of the universal relaxation bound τ×T≥ħ/π in black-hole physics (here τ≡1/ℑω0 is the characteristic relaxation time of the composed black-hole-scalar-field system, and T is the Bekenstein–Hawking temperature of the black hole. In particular, it is shown that the relaxation dynamics of charged massive scalar fields in the charged Reissner–Nordström black-hole spacetime may saturate this quantum time-times-temperature inequality. Interestingly, we prove that potential violations of the bound by light scalar fields are excluded by the Schwinger-type pair-production mechanism (a vacuum polarization effect, a quantum phenomenon which restricts the physical parameters of the composed black-hole-charged-field system to the regime qQ≪M2μ2/ħ.
Directory of Open Access Journals (Sweden)
Jie Yang
2014-01-01
Full Text Available We study the effect of ultrahigh energy collisions of two particles with different energies near the horizon of a 2+1 dimensional BTZ black hole (BSW effect. We find that the particle with the critical angular momentum could exist inside the outer horizon of the BTZ black hole regardless of the particle energy. Therefore, for the nonextremal BTZ black hole, the BSW process is possible on the inner horizon with the fine tuning of parameters which are characterized by the motion of particle, while, for the extremal BTZ black hole, the particle with the critical angular momentum could only exist on the degenerated horizon, and the BSW process could also happen there.
A no-short scalar hair theorem for rotating Kerr black holes
Hod, Shahar
2016-06-01
If a black hole has hair, how short can this hair be? A partial answer to this intriguing question was recently provided by the ‘no-short hair’ theorem which asserts that the external fields of a spherically symmetric electrically neutral hairy black-hole configuration must extend beyond the null circular geodesic which characterizes the corresponding black-hole spacetime. One naturally wonders whether the no-short hair inequality {r}{hair}\\gt {r}{null} is a generic property of all electrically neutral hairy black-hole spacetimes. In this paper we provide evidence that the answer to this interesting question may be positive. In particular, we prove that the recently discovered cloudy Kerr black-hole spacetimes—non-spherically symmetric non-static black holes which support linearized massive scalar fields in their exterior regions—also respect this no-short hair lower bound. Specifically, we analytically derive the lower bound {r}{field}/{r}+\\gt {r}+/{r}- on the effective lengths of the external bound-state massive scalar clouds (here {r}{field} is the peak location of the stationary bound-state scalar fields and r ± are the horizon radii of the black hole). Remarkably, this lower bound is universal in the sense that it is independent of the physical parameters (proper mass and angular harmonic indices) of the exterior scalar fields. Our results suggest that the lower bound {r}{hair}\\gt {r}{null} may be a general property of asymptotically flat electrically neutral hairy black-hole configurations.
Ohta, Nobuyoshi
2013-01-01
We study charged black hole solutions in Einstein-Maxwell-Gauss-Bonnet theory with the dilaton field which is the low-energy effective theory of the heterotic string. The spacetime is $D$-dimensional and assumed to be static and plane symmetric with the $(D-2)$-dimensional constant curvature space and asymptotically anti-de Sitter. By imposing the boundary conditions of the existence of the regular black hole horizon and proper behavior at infinity where the Breitenlohner-Freedman bound should be satisfied, we construct black hole solutions numerically. We give the relations among the physical quantities of the black holes such as the horizon radius, the mass, the temperature, and so on. The properties of the black hole do not depend on the dimensions qualitatively, which is different from the spherically symmetric and asymptotically flat case. There is non-zero lower limit for the radius of the event horizon below which no solution exists. The temperature of the black hole becomes smaller as the horizon radi...