Charged black holes on a Kaluza-Klein bubble
Kunz, Jutta; Yazadjiev, Stoytcho
2009-01-15
We construct a solution of two black holes on a Kaluza-Klein bubble in Einstein-Maxwell-dilaton theory. We explore the consequences of the presence of charge for the properties of this solution, and obtain a generalized Smarr relation and first law.
Hawking radiation from squashed Kaluza-Klein black holes: A window to extra dimensions
Ishihara, Hideki; Soda, Jiro
2007-09-15
We explore the observability of extra dimensions through five-dimensional squashed Kaluza-Klein black holes residing in the Kaluza-Klein spacetime. With the expectation that the Hawking radiation reflects the five-dimensional nature of the squashed horizon, we study the Hawking radiation of a scalar field in the squashed black hole background. As a result, we show that the luminosity of Hawking radiation tells us the size of the extra dimension, namely, the squashed Kaluza-Klein black holes open a window to extra dimensions.
Angular Momentum-Free of the Entropy Relations for Rotating Kaluza-Klein Black Holes
NASA Astrophysics Data System (ADS)
Liu, Hang; Meng, Xin-he
2016-11-01
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.
Angular Momentum-Free of the Entropy Relations for Rotating Kaluza-Klein Black Holes
NASA Astrophysics Data System (ADS)
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.
Strong gravitational lensing in a charged squashed Kaluza-Klein Gödel black hole
NASA Astrophysics Data System (ADS)
Sadeghi, J.; Naji, J.; Vaez, H.
2014-01-01
In this Letter we investigate the strong gravitational lansing in a charged squashed Kaluza-Klein Gödel 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 abar and bbar. We suppose that the supermassive black hole in the galaxy center can be considered by a charged squashed Kaluza-Klein black hole in a Gödel background. Then by the relations between lensing parameters and observables, we estimate the observables for different values of charge, extra dimension and Gödel parameters.
Hawking radiation as tunneling from squashed Kaluza-Klein black hole
Matsuno, Ken; Umetsu, Koichiro
2011-03-15
We discuss Hawking radiation from a five-dimensional squashed Kaluza-Klein black hole on the basis of the tunneling mechanism. A simple method, which was recently suggested by Umetsu, may be used to extend the original derivation by Parikh and Wilczek to various black holes. That is, we use the two-dimensional effective metric, which is obtained by the dimensional reduction near the horizon, as the background metric. Using the same method, we derive both the desired result of the Hawking temperature and the effect of the backreaction associated with the radiation in the squashed Kaluza-Klein black hole background.
Hawking radiation in a rotating Kaluza-Klein black hole with squashed horizons
Chen Songbai; Wang Bin; Su Rukeng
2008-01-15
We explore the signature of the extra dimension in the Hawking radiation in a rotating Kaluza-Klein black hole with squashed horizons. Comparing with the spherical case, we find that the rotating parameter brings richer physics. We obtain the appropriate size of the extra dimension which can enhance the Hawking radiation and may open a window to detect the extra dimensions.
Uniqueness theorem for Kaluza-Klein black holes in five-dimensional minimal supergravity
Tomizawa, Shinya
2010-11-15
We show a uniqueness theorem for Kaluza-Klein black holes in the bosonic sector of five-dimensional minimal supergravity. More precisely, under the assumptions of the existence of two commuting axial isometries and a nondegenerate connected event horizon of the cross-section topology S{sup 3}, or lens space, we prove that a stationary charged rotating Kaluza-Klein black hole in five-dimensional minimal supergravity is uniquely characterized by its mass, two independent angular momenta, electric charge, magnetic flux, and nut charge, provided that there exists neither a nut nor a bolt (a bubble) in the domain of outer communication. We also show that under the assumptions of the same symmetry, same asymptotics, and the horizon cross section of S{sup 1}xS{sup 2}, a black ring within the same theory--if it exists--is uniquely determined by its dipole charge and rod intervals besides the charges and magnetic flux.
Hawking Radiation via Damour-Ruffini Method in Squashed Charged Rotating Kaluza-Klein Black Holes
NASA Astrophysics Data System (ADS)
Hu, Ji-Wan; Wu, Jing-He; Liu, Xian-Ming
2016-12-01
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.
Hawking Radiation via Damour-Ruffini Method in Squashed Charged Rotating Kaluza-Klein Black Holes
NASA Astrophysics Data System (ADS)
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.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
NASA Astrophysics Data System (ADS)
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.
Improved generating technique for D=5 supergravities and squashed Kaluza-Klein black holes
Gal'tsov, Dmitri V.; Scherbluk, Nikolai G.
2009-03-15
Recently we suggested a solution-generating technique for five-dimensional supergravity with three Abelian vector fields based on the hidden SO(4,4) symmetry of the three-dimensionally reduced theory. This technique generalizes the G{sub 2(2)} generating technique developed earlier for minimal five-dimensional supergravity (A. Bouchareb, G. Clement, C-M. Chen, D. V. Gal'tsov, N. G. Scherbluk, and Th. Wolf, Phys. Rev. D 76, 104032 (2007)) and provides a new matrix representation for cosets forming the corresponding sigma-models in both cases. Here we further improve these methods introducing a matrix-valued dualization procedure which helps to avoid difficulties associated with solving the dualization equations in the component form. This new approach is used to generate a five-parametric rotating charged Kaluza-Klein black hole with the squashed horizon adding one parameter more to the recent solution by Tomizawa, Yasui, and Morisawa, which was constructed using the previous version of the G{sub 2(2)} generating technique.
Uniqueness theorem for black holes with Kaluza-Klein asymptotic in 5D Einstein-Maxwell gravity
Yazadjiev, Stoytcho
2010-07-15
In the present paper, we prove a uniqueness theorem for stationary multi-black hole configurations with Kaluza-Klein asymptotic in a certain sector of 5D Einstein-Maxwell gravity. As a part of the technical assumptions in the theorem, we assume that the Killing vector associated with the compact dimension is orthogonal to the other Killing vectors and that it is also hypersurface orthogonal. About the Maxwell field, we assume that it is invariant under the Killing symmetries and has a nonzero component only along the Killing vector associated with the compact dimension. We show that such multi-black hole configurations are uniquely specified by the interval structure, angular momenta of the horizons, magnetic charges, and the magnetic flux. A straightforward generalization of the uniqueness theorem for 5D Einstein-Maxwell-dilaton gravity is also given.
Evolution of perturbations of squashed Kaluza-Klein black holes: Escape from instability
Ishihara, Hideki; Kimura, Masashi; Konoplya, Roman A.; Murata, Keiju; Soda, Jiro; Zhidenko, Alexander
2008-04-15
The squashed Kaluza-Klien (KK) black holes differ from the Schwarzschild black holes with asymptotic flatness or the black strings even at energies for which the KK modes are not excited yet, so that squashed KK black holes open a window in higher dimensions. Another important feature is that the squashed KK black holes are apparently stable and, thereby, let us avoid the Gregory-Laflamme instability. In the present paper, the evolution of scalar and gravitational perturbations in time and frequency domains is considered for these squashed KK black holes. The scalar field perturbations are analyzed for general rotating squashed KK black holes. Gravitational perturbations for the so-called zero mode are shown to be decayed for nonrotating black holes, in concordance with the stability of the squashed KK black holes. The correlation of quasinormal frequencies with the size of extra dimension is discussed.
Thermodynamics of rotating Kaluza-Klein black holes in gravity's rainbow
NASA Astrophysics Data System (ADS)
Alsaleh, Salwa
2017-04-01
In this paper, a four-dimensional rotating Kaluza Klien (K-K) black hole was deformed using rainbow functions derived from loop quantum gravity and non-commutative geometry. We studied the thermodynamic properties and critical phenomena of this deformed black hole. The deformed temperature and entropy showed the existence of a Planckian remnant. The calculation of Gibbs free energy G for the ordinary and deformed black holes showed that both share a similar critical behaviour.
Savina, M. V.
2015-06-15
A survey of the results of the Compact Muon Solenoid (CMS) experiment that concern searches for massive Kaluza-Klein graviton excitations and microscopic black holes, quantum black holes, and string balls within models of low-energy multidimensional gravity is presented on behalf of the CMS Collaboration. The analysis in question is performed on the basis of a complete sample of data accumulated for proton-proton collisions at the c.m. energies of 7 and 8 TeV at the Large Hadron Collider (LHC) over the period spanning 2010 and 2012.
NASA Astrophysics Data System (ADS)
Wu, Shuang-Qing; Wang, He
2015-05-01
In a previous paper [S. Q. Wu, Phys. Rev. D 83, 121502(R) (2011)], a new kind of metric ansatz was found to fairly describe all already-known black hole solutions in the ungauged Kaluza-Klein (KK) supergravity theories. That metric ansatz somewhat resembles the famous Kerr-Schild (KS) form, but it is different from the KS one in two distinct aspects. That is, apart from a global conformal factor, the metric ansatz can be written as a vacuum background spacetime plus a "perturbation" modification term, the latter of which is associated with a timelike geodesic vector field rather than a null geodesic congruence in the usual KS ansatz. Replacing the flat vacuum background metric by the (anti-)de Sitter [(A)dS] spacetime, the general rotating charged KK-(A)dS black hole solutions in all higher dimensions have been successfully constructed and put into a unified form. In this paper, we shall study this novel metric ansatz in detail, aiming at achieving some inspiration as to the construction of rotating charged AdS black holes with multiple charges in other gauged supergravity theories. We find that the traditional perturbation expansion method often successfully used in the KS form is no longer useful in our new ansatz, since here no good parameter can be chosen as a suitable perturbation indicator. In order to investigate the metric properties of the general KK-AdS solutions, in this paper we devise a new effective method, dubbed the background metric expansion method, which can be thought of as a generalization of the perturbation expansion method, to deal with the Lagrangian and all equations of motion. In addition to two previously known conditions, namely the timelike and geodesic properties of the vector, we get three additional constraints via contracting the Maxwell and Einstein equations once or twice with this timelike geodesic vector. In particular, we find that these are a simpler set of sufficient conditions to determine the vector and the dilaton scalar
Rotating black ring on Kaluza-Klein bubbles
Nedkova, Petya G.; Yazadjiev, Stoytcho S.
2010-08-15
We construct a new exact solution to the 5D Einstein equations describing a rotating black ring with a single angular momentum surrounded by two Kaluza-Klein bubbles. The solution is generated by two-soliton Baecklund transformation. Its physical properties are computed and analyzed. The corresponding static solution, the rotating black string, and the boosted black string are reproduced as limits.
Harrison transformation and charged black objects in Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
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.
NASA Astrophysics Data System (ADS)
Jana, Sanjib; Krishnan, Chethan
2014-05-01
We generalize the results of arXiv:1212.1875 and arXiv:1212.6919 on attraction basins and their boundaries to the case of a specific class of rotating black holes, namely the ergo-free branch of extremal black holes in Kaluza-Klein theory. We find that exact solutions that span the attraction basin can be found even in the rotating case by appealing to certain symmetries of the equations of motion. They are characterized by two asymptotic parameters that generalize those of the non-rotating case, and the boundaries of the basin are spinning versions of the (generalized) subtractor geometry. We also give examples to illustrate that the shape of the attraction basin can drastically change depending on the theory.
Enhanced line signals from annihilating Kaluza-Klein dark matter
NASA Astrophysics Data System (ADS)
Arina, Chiara; Bringmann, Torsten; Silk, Joseph; Vollmann, Martin
2014-10-01
Monochromatic gamma ray lines have long been known to provide potential smoking-gun signals for annihilating dark matter. Here, we demonstrate that the situation is particularly interesting for Kaluza-Klein dark matter because resonant annihilation is generically expected for small, but not necessarily vanishing relative velocities of the annihilating particles. We calculate the contribution from those hitherto neglected resonances and show that the annihilation rate into monochromatic photons can be significantly enhanced, in a way that is much more pronounced than for the associated production of continuum photons. For favorable astrophysical conditions, this leads to promising prospects for the detection of TeV-scale Kaluza-Klein dark matter. We also point out that the situation may be even more interesting in the vicinity of black holes, like the supermassive black hole at the center of our Galaxy, where in principle center-of-mass energies much larger than the rest mass are available. In this case, annihilating Kaluza-Klein dark matter may show the striking and unique signature of several gamma ray lines, with an equidistant spacing corresponding to twice the compactification radius of the extra dimension.
Hoop conjecture and the horizon formation cross section in Kaluza-Klein spacetimes
Yoo, Chul-Moon; Ishihara, Hideki; Kimura, Masashi; Tanzawa, Sugure
2010-01-15
We analyze momentarily static initial data sets of the gravitational field produced by two-point sources in five-dimensional Kaluza-Klein spacetimes. These initial data sets are characterized by the mass, the separation of sources and the size of an extra dimension. Using these initial data sets, we discuss the condition for black hole formation, and propose a new conjecture which is a hybrid of the four-dimensional hoop conjecture and the five-dimensional hyperhoop conjecture. By using the new conjecture, we estimate the cross section of black hole formation due to collisions of particles in Kaluza-Klein spacetimes. We show that the mass dependence of the cross section gives us information about the size and the number of the compactified extra dimensions.
Black Holes in Higher Dimensions
NASA Astrophysics Data System (ADS)
Horowitz, Gary T.
2012-04-01
List of contributors; Preface; Part I. Introduction: 1. Black holes in four dimensions Gary Horowitz; Part II. Five Dimensional Kaluza-Klein Theory: 2. The Gregory-Laflamme instability Ruth Gregory; 3. Final state of Gregory-Laflamme instability Luis Lehner and Frans Pretorius; 4. General black holes in Kaluza-Klein theory Gary Horowitz and Toby Wiseman; Part III. Higher Dimensional Solutions: 5. Myers-Perry black holes Rob Myers; 6. Black rings Roberto Emparan and Harvey Reall; Part IV. General Properties: 7. Constraints on the topology of higher dimensional black holes Greg Galloway; 8. Blackfolds Roberto Emparan; 9. Algebraically special solutions in higher dimensions Harvey Reall; 10. Numerical construction of static and stationary black holes Toby Wiseman; Part V. Advanced Topics: 11. Black holes and branes in supergravity Don Marolf; 12. The gauge/gravity duality Juan Maldacena; 13. The fluid/gravity correspondence Veronika Hubeny, Mukund Rangamani and Shiraz Minwalla; 14. Horizons, holography and condensed matter Sean Hartnoll; Index.
Acceleration of particles in Einstein-Maxwell-dilaton black holes
NASA Astrophysics Data System (ADS)
Mao, Pu-Jian; Li, Ran; Jia, Lin-Yu; Ren, Ji-Rong
2017-06-01
It has recently been pointed out that, under certain conditions, the energy of particles accelerated by black holes in the center-of-mass frame can become arbitrarily high. In this paper, we study the collision of two particles in the case of four-dimensional charged nonrotating, extremal charged rotating and near-extremal charged rotating Kaluza-Klein black holes as well as the naked singularity case in Einstein-Maxwell-dilaton theory. We find that the center-of-mass energy for a pair of colliding particles is unlimited at the horizon of charged nonrotating Kaluza-Klein black holes, extremal charged rotating Kaluza-Klein black holes and in the naked singularity case. Supported by NSFC (11575202, 11205048), Foundation for Young Key Teacher of Henan Normal University and Cuiying Programme of Lanzhou University (225000-582404) and Fundamental Research Fund for Physics and Mathematic of Lanzhou University (LZULL200911)
Electroweak Kaluza-Klein dark matter
Flacke, Thomas; Kang, Dong Woo; Kong, Kyoungchul; ...
2017-04-07
In models with universal extra dimensions (UED), the lightest Kaluza-Klein excitation of neutral electroweak gauge bosons is a stable, weakly interacting massive particle and thus is a candidate for dark matter thanks to Kaluza-Klein parity. We examine concrete model realizations of such dark matter in the context of non-minimal UED extensions. The boundary localized kinetic terms for the electroweak gauge bosons lead to a non-trivial mixing among the first Kaluza-Klein excitations of themore » $${\\rm SU}(2)_W$$ and $${\\rm U}(1)_Y$$ gauge bosons and the resultant low energy phenomenology is rich. We investigate implications of various experiments including low energy electroweak precision measurements, direct and indirect detection of dark matter particles and direct collider searches at the LHC. Furthermore, we show that the electroweak Kaluza-Klein dark matter can be as heavy as 2.4 TeV, which is significantly higher than $1.3$ TeV as is indicated as an upper bound in the minimal UED model.« less
Electroweak Kaluza-Klein dark matter
NASA Astrophysics Data System (ADS)
Flacke, Thomas; Kang, Dong Woo; Kong, Kyoungchul; Mohlabeng, Gopolang; Park, Seong Chan
2017-04-01
In models with universal extra dimensions (UED), the lightest Kaluza-Klein excitation of neutral electroweak gauge bosons is a stable, weakly interacting massive particle and thus is a candidate for dark matter thanks to Kaluza-Klein parity. We examine concrete model realizations of such dark matter in the context of non-minimal UED extensions. The boundary localized kinetic terms for the electroweak gauge bosons lead to a non-trivial mixing among the first Kaluza-Klein excitations of the SU(2) W and U(1) Y gauge bosons and the resultant low energy phenomenology is rich. We investigate implications of various experiments including low energy electroweak precision measurements, direct and indirect detection of dark matter particles and direct collider searches at the LHC. Notably, we show that the electroweak Kaluza-Klein dark matter can be as heavy as 2.4 TeV, which is significantly higher than 1.3 TeV as is indicated as an upper bound in the minimal UED model.
Phantom black holes and sigma models
Azreg-Aienou, Mustapha; Clement, Gerard; Fabris, Julio C.; Rodrigues, Manuel E.
2011-06-15
We construct static multicenter solutions of phantom Einstein-Maxwell-dilaton theory from null geodesics of the target space, leading to regular black holes without spatial symmetry for certain discrete values of the dilaton coupling constant. We also discuss the three-dimensional gravitating sigma models obtained by reduction of phantom Einstein-Maxwell, phantom Kaluza-Klein and phantom Einstein-Maxwell-dilaton-axion theories. In each case, we generate by group transformations phantom charged black hole solutions from a neutral seed.
Kaluza-Klein Physics at Muon Colliders
Rizzo, Thomas G.
1999-11-04
We discuss the physics of Kaluza-Klein excitations of the Standard Model gauge bosons that can be explored by a high energy muon collider in the era after the LHC and TeV Linear Collider. We demonstrate that the muon collider is a necessary ingredient in the unraveling the properties of such states and, perhaps, proving their existence. The possibility of observing the resonances associated with the excited KK graviton states of the Randall-Sundrum model is also discussed.
Motion in Kaluza-Klein type theories
Kahil, M.E.
2006-05-15
Path and path deviation equations for charged, spinning and spinning charged objects in different versions of Kaluza-Klein (KK) theory using a modified Bazanski Lagrangian have been derived. The significance of motion in five dimensions, especially for a charged spinning object, has been examined. We have also extended the modified Bazanski approach to derive the path and path deviation equations of a test particle in a version of non-symmetric KK theory.
Fermions tunnelling from the charged dilatonic black holes
NASA Astrophysics Data System (ADS)
Chen, De-You; Jiang, Qing-Quan; Zu, Xiao-Tao
2008-10-01
Kerner and Mann's recent work shows that for an uncharged and non-rotating black hole its Hawking temperature can be correctly derived by fermions tunnelling from its horizons. In this paper, our main work is to improve the analysis to deal with charged fermion tunnelling from the general dilatonic black holes, specifically including the charged, spherically symmetric dilatonic black hole, the rotating Einstein Maxwell dilaton axion (EMDA) black hole and the rotating Kaluza Klein (KK) black hole. As a result, the correct Hawking temperatures are well recovered by charged fermions tunnelling from these black holes.
Galactic entropy in extended Kaluza-Klein cosmology
NASA Astrophysics Data System (ADS)
Yanar, Hilmi; Salti, Mustafa; Aydogdu, Oktay; Acikgoz, Irfan; Yasar, Erol
2016-02-01
We use a Kaluza-Klein model with variable cosmological and gravitational terms to discuss the nature of galactic entropy function. For this purpose, we assume a universe filled with dark fluid and consider five-dimensional (5D) field equations using the Gamma law equation. We mainly discuss the validity of the first and generalized second laws of galactic thermodynamics for viable Kaluza-Klein models.
Kaluza-Klein relics from warped reheating
Berndsen, Aaron; Cline, James M.; Stoica, Horace
2008-06-15
It has been suggested that after brane-antibrane inflation in a Klebanov-Strassler (KS) warped throat, metastable Kaluza-Klein excitations can be formed due to nearly-conserved angular momenta along isometric directions in the throat. If sufficiently long lived, these relics could conflict with big bang nucleosynthesis or baryogenesis by dominating the energy density of the Universe. We make a detailed estimate of the decay rate of such relics using the low-energy effective action of type IIB string theory compactified on the throat geometry, with attention to powers of the warp factor. We find that it is necessary to turn on supersymmetry (SUSY)-breaking deformations of the KS background in order to ensure that the most dangerous relics will decay fast enough. The decay rate is found to be much larger than the naive guess based on the dimension of the operators which break the angular isometries of the throat. For an inflationary warp factor of order w{approx}10{sup -4}, we obtain the bound M{sub 3/2} > or approx. 10{sup 9} GeV on the scale of SUSY breaking to avoid cosmological problems from the relics, which is satisfied in the Kachru, Kallosh, Linde, and Trivedi construction assumed to stabilize the compactification. Given the requirement that the relics decay before nucleosynthesis or baryogenesis, we place bounds on the mass of the relic as a function of the warp factor in the throat for more general warped backgrounds.
Kaluza-Klein gravitons at LHC2
NASA Astrophysics Data System (ADS)
Dillon, Barry M.; Sanz, Veronica
2017-08-01
In this work we study constraints from new searches for heavy particles at the LHC on the allowed masses and couplings of a Kaluza-Klein (KK) graviton in a holographic composite Higgs model. Keeping new electroweak states heavy such that electroweak precision tests are satisfied, we control the mass of the lightest KK graviton using a brane kinetic term. With this we study KK graviton masses from 0.5-3 TeV. In our analysis we also employ little Randall-Sundrum (RS) models, characterized by a lower UV scale in the five-dimensional model which in turn implies modified couplings to massless bulk fields. Viewing this scenario as a strongly coupled four-dimensional theory with a composite Higgs boson, the KK graviton is interpreted as a composite spin-2 state and the varying UV scale corresponds to a varying intermediate scale between the cutoff of the low-energy effective theory and the Planck scale. We find that KK gravitons with masses in the range [500, 3000] GeV are compatible with current collider constraints, where the most promising channels for detecting these states are the diphoton and Z Z channels. A detection is more likely in the little RS models, in which the dual gauge theory has a larger number of colors than in traditional RS models.
Entropy of 4D extremal black holes
NASA Astrophysics Data System (ADS)
Johnson, Clifford V.; Khuri, Ramzi R.; Myers, Robert C.
1996-02-01
We derive the Bekenstein-Hawking entropy formula for four-dimensional Reissner-Nordström extremal black holes in type II string theory. The derivation is performed in two separate (T-dual) weak coupling pictures. One uses a type IIB bound state problem of D5- and D1-branes, while the other uses a bound state problem of D0- and D4-branes with macroscopic fundamental type IIA strings. In both cases, the D-brane systems are also bound to a Kaluza-Klein monopole, which then yields the four-dimensional black hole at strong coupling.
Radion clouds around evaporating black holes
Morris, J. R.
2009-08-15
A Kaluza-Klein model, with a matter source associated with Hawking radiation from an evaporating black hole, is used to obtain a simple form for the radion effective potential. The environmental effect generally causes a matter-induced shift of the radion vacuum, resulting in the formation of a radion cloud around the hole. There is an albedo due to the radion cloud, with an energy-dependent reflection coefficient that depends upon the size of the extra dimensions and the temperature of the hole.
NASA Astrophysics Data System (ADS)
Peng, Jun-Jin
2017-05-01
In this paper, we investigate the conserved charges of generally diffeomorphism invariant gravity theories with a wide variety of matter fields, particularly of the theories with multiple scalar fields and p -form potentials, in the context of the off-shell generalized Abbott-Deser-Tekin (ADT) formalism. We first construct a new off-shell ADT current that consists of the terms for the variation of a Killing vector and expressions of the field equations as well as the Lie derivative of a surface term with respect to the Killing vector within the framework of generally diffeomorphism invariant gravity theories involving various matter fields. After deriving the off-shell ADT potential corresponding to this current, we propose a formula of conserved charges for these theories. Next, we derive the off-shell ADT potential associated with the generic Lagrangian that describes a large range of gravity theories with a number of scalar fields and p -form potentials. Finally, the properties of the off-shell generalized ADT charges for the theory of Einstein gravity and the gravity theories with a single p -form potential are investigated by performing Kaluza-Klein dimensional reduction along a compactified direction. The results indicate that the charge contributed by all the fields in the lower-dimensional theory is equal to that of the higher-dimensional one at mathematical level with the hypothesis that the higher-dimensional spacetime allows for the existence of the compactified dimension. In order to illustrate our calculations, the mass and angular momentum for the five-dimensional rotating Kaluza-Klein black holes are explicitly evaluated as an example.
Klein-Gordon oscillator in Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
Carvalho, Josevi; Carvalho, Alexandre M. de M.; Cavalcante, Everton; Furtado, Claudio
2016-07-01
In this contribution we study the Klein-Gordon oscillator on the curved background within the Kaluza-Klein theory. The problem of the interaction between particles coupled harmonically with topological defects in Kaluza-Klein theory is studied. We consider a series of topological defects, then we treat the Klein-Gordon oscillator coupled to this background, and we find the energy levels and corresponding eigenfunctions in these cases. We show that the energy levels depend on the global parameters characterizing these spacetimes. We also investigate a quantum particle described by the Klein-Gordon oscillator interacting with a cosmic dislocation in Som-Raychaudhuri spacetime in the presence of homogeneous magnetic field in a Kaluza-Klein theory. In this case, the energy spectrum is determined, and we observe that these energy levels represent themselves as the sum of the terms related with Aharonov-Bohm flux and of the parameter associated to the rotation of the spacetime.
Neutrinos from Kaluza-Klein dark matter in the Sun
Blennow, Mattias; Melbéus, Henrik; Ohlsson, Tommy E-mail: melbeus@kth.se
2010-01-01
We investigate indirect neutrino signals from annihilations of Kaluza-Klein dark matter in the Sun. Especially, we examine a five- as well as a six-dimensional model, and allow for the possibility that boundary localized terms could affect the spectrum to give different lightest Kaluza-Klein particles, which could constitute the dark matter. The dark matter candidates that are interesting for the purpose of indirect detection of neutrinos are the first Kaluza-Klein mode of the gauge boson and the neutral component of the gauge bosons. Using the DarkSUSY and WimpSim packages, we calculate muon fluxes at an Earth-based neutrino telescope, such as IceCube. For the five-dimensional model, the results that we obtained agree reasonably well with the results that have previously been presented in the literature, whereas for the six-dimensional model, we find that, at tree-level, the results are the same as for the five-dimensional model. Finally, if the first Kaluza-Klein mode of the gauge boson constitutes the dark matter, IceCube can constrain the parameter space. However, in the case that the neutral component of the gauge bosons is the LKP, the signal is too weak to be observed.
Finite temperature effective potential in a Kaluza-Klein universe
Roy, P. )
1990-01-20
The authors evaluate the finite temperature one-loop effective potential for scalar fields in Kaluza-Klein universe consisting of the product of a space with open Robertson-Walker metric and the N sphere S{sup N}. The one-loop effective potential has been computed in both high and low temperature limits.
Cosmological model of the Kaluza-Klein type
Kopczyn-ski, W.
1987-12-15
The theory of a fluid composed of multidimensional objects is joined with the Kaluza-Klein idea with the following aim: an explanation of the distinction between the internal and the external spaces. On the cosmic scale, the internal space contracts and the external space expands. A formula for the rate of decrease of the gravitational constant is discussed.
Residue theorem and summing over Kaluza-Klein excitations
Feng Taifu; Chen Jianbin; Gao Tiejun; Sun Kesheng
2011-11-01
Applying the equations of motion together with corresponding boundary conditions of bulk profiles at infrared and ultraviolet branes, we verify some lemmas on the eigenvalues of Kaluza-Klein modes in extension of the standard model with a warped extra dimension and the custodial symmetry SU(3){sub c}xSU(2){sub L}xSU(2){sub R}xU(1){sub X}xP{sub LR}. Using the lemmas and performing properly analytic extensions of bulk profiles, we present the sufficient condition for a convergent series of Kaluza-Klein excitations and sum over the series through the residue theorem. The method can also be applied to sum over the infinite series of Kaluza-Klein excitations in a universal extra dimension. Furthermore, we analyze the possible connection between the propagators in five-dimensional full theory and the product of bulk profiles with corresponding propagators of exciting Kaluza-Klein modes in four-dimensional effective theory, and recover some relations presented in the literature for warped and universal extra dimensions, respectively. As an example, we present the correction from new physics to the branching ratio of B{yields}X{sub s{gamma}} to the order O({mu}{sub EW}{sup 2}/{Lambda}{sub KK}{sup 2}) in extension of the standard model with a warped extra dimension and the custodial symmetry, where {Lambda}{sub KK} denotes the energy scale of low-lying Kaluza-Klein excitations and {mu}{sub EW} denotes the electroweak energy scale.
State-relevant Maxwell's equation from Kaluza-Klein theory
Luan Jing; Ma Yongge; Ma Boqiang
2007-11-15
We study a five-dimensional perfect fluid coupled with Kaluza-Klein gravity. By dimensional reduction, a modified form of Maxwell's equation is obtained, which is relevant to the equation of state of the source. Since the relativistic magnetohydrodynamics and the three-dimensional formulation are widely used to study space matter, we derive the modified Maxwell's equations and relativistic magnetohydrodynamics in 3+1 form. We then take an ideal Fermi gas as an example to study the modified effect, which can be visible under high-density or high-energy conditions, while the traditional Maxwell's equation can be regarded as a result in the low density and low temperature limit. We also indicate the possibility to test the state-relevant effect of Kaluza-Klein theory in a telluric laboratory.
Static wormholes on the brane inspired by Kaluza-Klein gravity
Leon, J. Ponce de
2009-11-01
We use static solutions of 5-dimensional Kaluza-Klein gravity to generate several classes of static, spherically symmetric spacetimes which are analytic solutions to the equation {sup (4)}R = 0, where {sup (4)}R is the four-dimensional Ricci scalar. In the Randall and Sundrum scenario they can be interpreted as vacuum solutions on the brane. The solutions contain the Schwarzschild black hole, and generate new families of traversable Lorenzian wormholes as well as nakedly singular spacetimes. They generalize a number of previously known solutions in the literature, e.g., the temporal and spatial Schwarzschild solutions of braneworld theory as well as the class of self-dual Lorenzian wormholes. A major departure of our solutions from Lorenzian wormholes a la Morris and Thorne is that, for certain values of the parameters of the solutions, they contain three spherical surfaces (instead of one) which are extremal and have finite area. Two of them have the same size, meet the ''flare-out'' requirements, and show the typical violation of the energy conditions that characterizes a wormhole throat. The other extremal sphere is ''flaring-in'' in the sense that its sectional area is a local maximum and the weak, null and dominant energy conditions are satisfied in its neighborhood. After bouncing back at this second surface a traveler crosses into another space which is the double of the one she/he started in. Another interesting feature is that the size of the throat can be less than the Schwarzschild radius 2M, which no longer defines the horizon, i.e., to a distant observer a particle or light falling down crosses the Schwarzschild radius in a finite time.
Topology change in Kaluza-Klein and superstring theories
NASA Astrophysics Data System (ADS)
Tipler, Frank J.
1985-12-01
It is shown that topology change-for instance, true dynamical compactification - cannot occur in classical Kaluza-Klein and superstring theories without causality violation either in the form of a breakdown in predictability (a failure of global hyperbolicity), or in the form of closed timelike curves. This implies that if causality holds, then any topological distinction between the spacetime and internal dimensions either has to be present ab initio, or else must arise in the quantum gravity regime. Permanent address.
Constraints on cosmic superstrings from Kaluza-Klein emission.
Dufaux, Jean-François
2012-07-06
Cosmic superstrings interact generically with a tower of light and/or strongly coupled Kaluza-Klein (KK) modes associated with the geometry of the internal space. We study the production of KK particles by cosmic superstring loops, and show that it is constrained by big bang nucleosynthesis. We study the resulting constraints in the parameter space of the underlying string theory model and highlight their complementarity with the regions that can be probed by current and upcoming gravitational wave experiments.
Kaluza-Klein mesons in universal extra dimensions
De Pree, Erin; Sher, Marc
2005-11-01
In models with universal extra dimensions, the isosinglet Kaluza-Klein (KK) quarks (q{sup 1}) have very narrow widths, of O(5-10) MeV, and will thus hadronize. Studies of KK quarkonia (q{sup 1}q{sup 1}) show very sharp resonances and dramatic signatures at the linear collider. In this Brief Report, we consider the possibility of detecting KK mesons (q{sup 1}q), and show that detection at a linear collider is unlikely.
Causal Anomalies in Kaluza-Klein Gravity Theories
NASA Astrophysics Data System (ADS)
Rebouças, M. J.; Teixeira, A. F. F.
Causal anomalies in two Kaluza-Klein gravity theories are examined, particularly as to whether these theories permit solutions in which the causality principle is violated. It is found that similarly to general relativity the field equations of the space-time-mass Kaluza-Klein (STM-KK) gravity theory do not exclude violation of causality of Gödel type, whereas the induced matter Kaluza-Klein (IM-KK) gravity rules out noncausal Gödel-type models. The induced matter version of general relativity is shown to be an efficient therapy for causal anomalies that occurs in a wide class of noncausal geometries. Perfect fluid and dust Gödel-type solutions of the STM-KK field equations are studied. It is shown that every Gödel-type perfect fluid solution is isometric to the unique dust solution of the STM-KK field equations. The question as to whether 5D Gödel-type noncausal geometries induce any physically acceptable 4D energy-momentum tensor is also addressed.
Asymptotic safety and Kaluza-Klein gravitons at the LHC
Gerwick, Erik; Litim, Daniel; Plehn, Tilman
2011-04-15
We study Drell-Yan production at the LHC in low-scale quantum gravity models with extra dimensions. Asymptotic safety implies that the ultraviolet behavior of gravity is dictated by a fixed point. We show how the energy dependence of Newton's coupling regularizes the gravitational amplitude using a renormalization group improvement. We study LHC predictions and find that Kaluza-Klein graviton signals are well above standard model backgrounds. This leaves a significant sensitivity to the energy scale {Lambda}{sub T} where the gravitational couplings crossover from classical to fixed point scaling.
Massless fermions and Kaluza--Klein theory with torsion
Wu, Y.; Zee, A.
1984-09-01
A pure Kaluza--Klein theory contains no massless fermion in four-dimensional theory. We investigate the effect of introducing torsion on the internal manifold and find that there are massless fermions. The hope is that given an isometry group the representation to which these fermions belong is fixed, in contrast to the situation in Yang--Mills theory. We show that this is indeed the case, but the representations do not appear to be the ones favored by current theoretical prejudice. The cases with parallelizable torsions on a group manifold as the internal manifold are analyzed in detail.
Wormhole in 5D Kaluza-Klein cosmology
NASA Astrophysics Data System (ADS)
Biswas, Gargi; Modak, B.
2017-03-01
We present wormhole as a solution of Euclidean field equations as well as the solution of the Wheeler-deWitt (WD) equation satisfying Hawking-Page wormhole boundary conditions in (4 + 1)-dimensional Kaluza-Klein cosmology. The wormholes are considered in the cases of pure gravity, minimally coupled scalar (imaginary) field and with a positive cosmological constant assuming dynamical extra-dimensional space. In above cases, wormholes are allowed both from Euclidean field equations and WD equation. The dimensional reduction is possible.
Kaluza-Klein Dark Matter, Electrons and Gamma Ray Telescopes
Baltz, E.
2004-12-01
Kaluza-Klein dark matter particles can annihilate efficiently into electron-positron pairs, providing a discrete feature (a sharp edge) in the cosmic e{sup +} e{sup -} spectrum at an energy equal to the particle's mass (typically several hundred GeV to one TeV). Although this feature is probably beyond the reach of satellite or balloon-based cosmic ray experiments (those that distinguish the charge and mass of the primary particle), gamma ray telescopes may provide an alternative detection method. Designed to observe very high-energy gamma-rays, ACTs also observe the diffuse flux of electron-induced electromagnetic showers. The GLAST satellite, designed for gamma ray astronomy, will also observe any high energy showers (several hundred GeV and above) in its calorimeter. We show that high-significance detections of an electron-positron feature from Kaluza-Klein dark matter annihilations are possible with GLAST, and also with ACTs such as HESS, VERITAS or MAGIC.
The classical tests in Kaluza-Klein gravity
NASA Technical Reports Server (NTRS)
Kalligas, D.; Wesson, P. S.; Everitt, C. W. F.
1995-01-01
The possible existence of extra dimensions to spacetime can be tested astrophysically using Kaluza-Klein theory, which is a natural extension of Einsteins's general relativity. In the simplest version of the theory, there is a standard class of five-dimensional solutions that are analogous to the four-dimensional Schwarzschild solution. However, even a small departure of the extra dimension from flatness affects the first or dominant part of the potential, making it possible to test for the existence of an extra dimension. Data from the solar system indicate that in our region of space the terms due to the fifth dimension are small (less than or equal to 0.1%) compared to those due to the usual for dimensions of spacetime. However, the parameters of Kaluza-Klein theory are not universal constants and can vary from place to place depending on local physics. Hence other astrophysical systems may serve as better laboratories for investigating the possible existence of extra dimensions.
Supersymmetry: Kaluza-Klein theory, anomalies, and superstrings
Aref'eva, I.Y.; Volovich, I.V.
1985-08-01
Progress in the search for a unified theory of elementary particles is reviewed. The supersymmetrical Kaluza-Klein theories are described: 11-, 10-, and 6-dimensional models of supergravity. The methods of spontaneous compactification, with whose help the four-dimensional theories are obtained, are described. The properties of the massless sector: zero modes in the Kaluza-Klein theories: and the question of the stability of vacuum solutions are discussed. An important criterion for the selection of a self-consistent theory is the absence of anomalies. The basic formulas for multidimensional chiral and gravitational anomalies are presented. The mechanism of the cancellation of the anomaly for Green and Schwarz's 10-dimensional effective field theory of superstrings with the gauge groups SO(32) and E/sub 8/ x E/sub 8/ is described. The basic concepts and the results of the theory of superstrings are presented. This theory has no divergences and is at the present time a very attractive candidate for a unified theory of elementary particles.
Vacuum Stability in Kaluza-Klein Geometric Sigma Models
NASA Astrophysics Data System (ADS)
Vasilić, M.
2002-09-01
In Kaluza-Klein geometric sigma models, the scalar fields coupled to higher-dimensional gravity are pure gauge. The gauge fixed theory contains no matter fields, and can consistently be reduced to 4 dimensions, provided the internal space is chosen in the form of a group manifold. The effective 4-dimensional theory includes standard Einstein and Yang-Mills sectors, and is free of the classical cosmological constant problem. In this paper, the stability of the internal excitations is analyzed. It is shown that the initial Lagrangian can be modified to lead to a classically stable effective 4-dimensional theory, independently of the particular group used, and retaining all the basic features of the unmodified theory.
Cosmological and coupling constants in Kaluza-Klein supergravity
NASA Astrophysics Data System (ADS)
Duff, M. J.; Pope, C. N.; Warner, N. P.
1983-10-01
Weinberg's formula, relating the Yang-Mills coupling constant, g, to the size of the extra dimensions in a Kaluza-Klein theory, requires modification when gravity is coupled to antisymmetric tensor gauge fields. In particular, in the spontaneous compactification of d = 11 supergravity on the round S7 of radius m-, the Weinberg formula g2 = 64πGm2 is changed to g2 = 16πGm2 owing to the AMNP field. Combined with the cosmological constant relation Λ = 12m2 one finds 4πGΛ = -3g2, which is precisely the relation in the gauged N = 8 supergravity of de Wit and Nicolai. Present address: Lauritsen Laboratory, Californian Institute of Technology, Pasadena, CA 91125, USA.
The Spacetime Between Einstein and Kaluza-Klein: Further Explorations
NASA Astrophysics Data System (ADS)
Vuille, Chris
2017-01-01
Tensor multinomials can be used to create a generalization of Einstein's general relativity that in a mathematical sense falls between Einstein's original theory in four dimensions and the Kaluza-Klein theory in five dimensions. In the extended theory there are only four physical dimensions, but the tensor multinomials are expanded operators that can accommodate other forces of nature. The equivalent Ricci tensor of this geometry yields vacuum general relativity and electromagnetism, as well as a Klein-Gordon-like quantum scalar field. With a generalization of the stress-energy tensor, an exact solution for a plane-symmetric dust can be found where the scalar portion of the field drives early universe inflation, levels off for a period, then causes a later continued universal acceleration, a possible geometric mechanism for the inflaton or dark energy. Some new explorations of the equations, the problems, and possibilities will be presented and discussed.
Universal extra dimension: Violation of Kaluza-Klein parity
Bhattacherjee, Biplob
2009-01-01
The minimal universal extra dimension (mUED) model respects the Kaluza-Klein (KK) parity (-1){sup n}, where n is the KK number. However, it is possible to have interactions located at only one of the two fixed points of the S{sub 1}/Z{sub 2} orbifold. Such asymmetric interactions violate the KK parity. This kills the cold dark matter component of UED but also removes the upper bound on the inverse compactification radius, and thus nonobservation of the KK excitations even at the Large Hadron Collider does not necessarily invalidate the model. Apart from the decay of the lightest n=1 KK excitation, this leads to collider signals which are markedly different from those in the mUED scenario. The phenomenological consequences of such KK-parity violating terms are explored.
Hawking radiation from dilatonic black holes via anomalies
Jiang Qingquan; Cai Xu; Wu Shuangqing
2007-03-15
Recently, Hawking radiation from a Schwarzschild-type black hole via a gravitational anomaly at the horizon has been derived by Robinson and Wilczek. Their result shows that, in order to demand general coordinate covariance at the quantum level to hold in the effective theory, the flux of the energy-momentum tensor required to cancel the gravitational anomaly at the horizon of the black hole is exactly equal to that of (1+1)-dimensional blackbody radiation at the Hawking temperature. In this paper, we attempt to apply the analysis to derive Hawking radiation from the event horizons of static, spherically symmetric dilatonic black holes with arbitrary coupling constant {alpha}, and that from the rotating Kaluza-Klein ({alpha}={radical}(3)) as well as the Kerr-Sen ({alpha}=1) black holes via an anomalous point of view. Our results support Robinson and Wilczek's opinion. In addition, the properties of the obtained physical quantities near the extreme limit are qualitatively discussed.
An exact conformal symmetry Ansatz on Kaluza-Klein reduced TMG
NASA Astrophysics Data System (ADS)
Moutsopoulos, George; Ritter, Patricia
2011-11-01
Using a Kaluza-Klein dimensional reduction, and further imposing a conformal Killing symmetry on the reduced metric generated by the dilaton, we show an Ansatz that yields many of the known stationary axisymmetric solutions to TMG.
A New Point of View on General Kaluza-Klein Theories
NASA Astrophysics Data System (ADS)
Bejancu, A.
2012-09-01
The general Kaluza-Klein theories are physical theories in which both the ``cylinder condition" and the ``compactification condition" from the classical Kaluza-Klein theory are not necessarily satisfied. Our study is developed on a general Kaluza-Klein space (overline{M} = M × K,bar{g})}, whose tangent bundle T overline{M} splits into horizontal and vertical distributions H overline{M} and V overline{M}, respectively. The main tool in our new point of view is what we call the Riemannian horizontal connection nabla on H overline{M}, which plays in a general Kaluza-Klein theory, the same role as the Levi-Civita connection on the spacetime M in the classical Kaluza-Klein theory. This connection enables us to classify the geodesics of (overline{M},bar{g}), to define the horizontal Einstein gravitational tensor field, and to write down in a covariant form, the field equations on (overline{M},bar{g}) In particular, we apply the study to both the theory of Einstein-Bergmann spaces and the theory of general Kaluza-Klein spaces with bundle-like metric.
Warped Kaluza-Klein reduction from string duality
NASA Astrophysics Data System (ADS)
Schulz, Michael; Tammaro, Elliott
2014-03-01
Virtually all phenomenologically relevant string theory compactifications are of warped type, in which the overall scale factor of 4D spacetime varies over the internal dimensions. However, the procedure for Kaluza-Klein (KK) reduction is more poorly understood for warped compactifications than for standard compactifications. The simplest standard compactifications are compactifications on tori, and the simplest warped compactifications differ from these by the addition of parallel D-branes and O-branes. It is astonishing that a direct derivation of the dimensionally reduced action does not exist even for these simple warped compactifications (which are T-dual to Type I), although the answer is known on supersymmetry grounds. We fill this void. We derive the procedure for the KK reduction of a simple Type IIA warped compactification with D6 branes and O6 planes, via its lift to the standard compactification of M-theory on K3. Our derivation utilizes an approximate K3 metric of Gibbons-Hawking form, which is exactly equivalent to the classical type IIA supergravity description of the warped compactification. This material is based upon work supported by the National Science Foundation under Grant Nos. PHY09-12219 and PHY11-25915.
Teleparallel conformal invariant models induced by Kaluza-Klein reduction
NASA Astrophysics Data System (ADS)
Geng, Chao-Qiang; Luo, Ling-Wei
2017-06-01
We study the extensions of teleparallism in the Kaluza-Klein (KK) scenario by writing the analogous form to the torsion scalar TNGR in terms of the corresponding antisymmetric tensors, given by TNGR = a Tijk Tijk + b Tijk Tkji + c T j{}ji Tk{}k{}i , in the four-dimensional new general relativity (NGR) with arbitrary coefficients a, b and c. After the KK dimensional reduction, the Lagrangian in the Einstein-frame can be realized by taking 2a + b + c = 0 with the ghost-free condition c≤slant0 for the one-parameter family of teleparallelism. We demonstrate that the pure conformal invariant gravity models can be constructed by the requirements of 2a + b = 0 and c = 0. In particular, the torsion vector can be identified as the conformal gauge field, while the conformal gauge theory can be obtained by 2a + b + 4c = 0 or 2a + b = 0, which is described on the Weyl-Cartan geometry Y 4 with the ghost-free conditions 2a + b + c > 0 and c\
Cosmic super-strings and Kaluza-Klein modes
Dufaux, Jean-François
2012-09-01
Cosmic super-strings interact generically with a tower of relatively light and/or strongly coupled Kaluza-Klein (KK) modes associated with the geometry of the internal space. In this paper, we study the production of spin-2 KK particles by cusps on loops of cosmic F- and D-strings. We consider cosmic super-strings localized either at the bottom of a warped throat or in a flat internal space with large volume. The total energy emitted by cusps in KK modes is comparable in both cases, although the number of produced KK modes may differ significantly. We then show that KK emission is constrained by the photo-dissociation of light elements and by observations of the diffuse gamma ray background. We show that this rules out regions of the parameter space of cosmic super-strings that are complementary to the regions that can be probed by current and upcoming gravitational wave experiments. KK modes are also expected to play an important role in the friction-dominated epoch of cosmic super-string evolution.
The abundance of Kaluza-Klein dark matter with coannihilation
Burnell, Fiona; Kribs, Graham D.
2006-01-01
In universal extra dimension models, the lightest Kaluza-Klein (KK) particle is generically the first KK excitation of the photon and can be stable, serving as particle dark matter. We calculate the thermal relic abundance of the KK photon for a general mass spectrum of KK excitations including full coannihilation effects with all (level-one) KK excitations. We find that including coannihilation can significantly change the relic abundance when the coannihilating particles are within about 20% of the mass of the KK photon. Matching the relic abundance with cosmological data, we find the mass range of the KK photon is much wider than previously found, up to about 2 TeV if the masses of the strongly interacting level-one KK particles are within 5% of the mass of the KK photon. We also find cases where several coannihilation channels compete (constructively and destructively) with one another. The lower bound on the KK photon mass, about 540 GeV when just right-handed KK leptons coannihilate with the KK photon, relaxes upward by several hundred GeV when coannihilation with electroweak KK gauge bosons of the same mass is included.
Direct detection of Kaluza-Klein particles in neutrino telescopes
Albuquerque, Ivone F. M.; Burdman, Gustavo; Krenke, Christopher A.; Nosratpour, Baran
2008-07-01
In theories with universal extra dimensions, all standard model fields propagate in the bulk and the lightest state of the first Kaluza-Klein (KK) level can be made stable by imposing a Z{sub 2} parity. We consider a framework where the lightest KK particle (LKP) is a neutral, extremely weakly interacting particle such as the first KK excitation of the graviton, while the next-to-lightest KK particle (NLKP) is the first KK mode of a charged right-handed lepton. In such a scenario, due to its very small couplings to the LKP, the NLKP is long-lived. We investigate the production of these particles from the interaction of high energy neutrinos with nucleons in the Earth and determine the rate of NLKP events in neutrino telescopes. Using the Waxman-Bahcall limit for the neutrino flux, we find that the rate can be as large as a few hundreds of events a year for realistic values of the NLKP mass.
Gravitational tension, spacetime pressure and black hole volume
NASA Astrophysics Data System (ADS)
Armas, Jay; Obers, Niels A.; Sanchioni, Marco
2016-09-01
We study the first law of black hole thermodynamics in the presence of surrounding gravitational fields and argue that variations of these fields are naturally incorporated in the first law by defining gravitational tension or gravitational binding energy. We demonstrate that this notion can also be applied in Anti-de Sitter spacetime, in which the surrounding gravitational field is sourced by a cosmological fluid, therefore showing that spacetime volume and gravitational tension encode the same physics as spacetime pressure and black hole volume. We furthermore show that it is possible to introduce a definition of spacetime pressure and black hole volume for any spacetime with characteristic length scales which does not necessarily require a cosmological constant sourcing Einstein equations. However, we show that black hole volume is non-universal in the flat spacetime limit, questioning its significance. We illustrate these ideas by studying the resulting black hole volume of Kaluza-Klein black holes and of a toy model for a black hole binary system in five spacetime dimensions (the black saturn solution) as well as of several novel perturbative black hole solutions. These include the higher-dimensional Kerr-Newman solution in Anti-de Sitter spacetime as well as other black holes in plane wave and Lifshitz spacetimes.
Spectroscopy of the Rotating Kaluza-Klein Spacetime via Revisited Adiabatic Invariant Quantity
NASA Astrophysics Data System (ADS)
Yu, Li; Qi, De-Jiang
2017-07-01
In this paper, we have investigated the spectroscopy of the rotating Kaluza-Klein spacetime by applying Bohr-Sommerfeld quantization rule and the first law of thermodynamics. we derived the expression of the adiabatic invariant quantity in the dragged-Painlevé coordinate system. Then, via revisited adiabatic invariant quantity, we derive the area and entropy spectra of the spacetime. We obtained the area spectrum of the Kaluza-Klein spacetime is {Δ } A=8π {lP2}, and the entropy spectrum is Δ S = 2 π. This result is consistent with the Bekenstein's original result, which imply the entropy and horizon area are discrete and equidistant for the spacetime.
Bohr-Sommerfeld Quantization of Hydrogen-Like Atoms in Kaluza-Klein Theory
NASA Astrophysics Data System (ADS)
Wilson, Weldon J.
1984-12-01
A low energy phenomenon in quantum theories with extra dimensions is studied. The method of Bohr and Sommerfeld is used to compute the relativistic bound state energy spectrum for hydrogen-like atoms in the flat, five-dimensional Kaluza-Klein model.
Z boson decay to photon plus Kaluza Klein graviton: large extra dimensional bounds
NASA Astrophysics Data System (ADS)
Allanach, B. C.; Skittrall, J. P.
2008-05-01
We consider the phenomenology of the decay of a Z boson into a photon and a Kaluza Klein excitation of the graviton in the ADD model. Using LEP data, we obtain an upper bound on the branching ratio corresponding to this process of ˜10-11. We also investigate energy profiles of the process.
Kaluza-Klein reduction of low-energy effective actions: geometrical approach
NASA Astrophysics Data System (ADS)
Vysoký, Jan
2017-08-01
Equations of motion of low-energy string effective actions can be conveniently described in terms of generalized geometry and Levi-Civita connections on Courant algebroids. This approach is used to propose and prove a suitable version of the Kaluza-Klein-like reduction. Necessary geometrical tools are recalled.
On Pauli's Invention of Non-Abelian Kaluza-Klein Theory in 1953
NASA Astrophysics Data System (ADS)
Straumann, N.
2002-12-01
There are documents which show that Wolfgang Pauli developed in 1953 the first consistent generalization of the five-dimensional theory of Kaluza, Klein, Fock and others to a higher dimensional internal space. Because he saw no way to give masses to the gauge bosons, he refrained from publishing his results formally.
Deformed phase space Kaluza-Klein cosmology and late time acceleration
NASA Astrophysics Data System (ADS)
Sabido, M.; Yee-Romero, C.
2016-06-01
The effects of phase space deformations on Kaluza-Klein cosmology are studied. The deformation is introduced by modifying the symplectic structure of the minisuperspace variables. In the deformed model, we find an accelerating scale factor and therefore infer the existence of an effective cosmological constant from the phase space deformation parameter β.
Quantum (in)stability of 2D charged dilaton black holes and 3D rotating black holes
NASA Astrophysics Data System (ADS)
Nojiri, Shin'ichi; Odintsov, Sergei D.
1999-02-01
The quantum properties of charged black holes (BHs) in two-dimensional (2D) dilaton-Maxwell gravity (spontaneously compactified from heterotic string) with N dilaton coupled scalars are studied. We first investigate 2D BHs found by McGuigan, Nappi, and Yost. Kaluza-Klein reduction of 3D gravity with minimal scalars leads also to 2D dilaton-Maxwell gravity with dilaton coupled scalars and the rotating BH solution found by Bañados, Teitelboim, and Zanelli, which can be also described by 2D charged dilatonic BHs. Evaluating the one-loop effective action for dilaton coupled scalars in large N (and the s-wave approximation for the Bañados-Teitelboim-Zanelli case), we show that quantum-corrected BHs may evaporate or else antievaporate similarly to 4D Nariai BHs as is observed by Bousso and Hawking. Higher modes may cause the disintegration of BHs in accordance with recent observation by Bousso.
Brügmann, B.; Ghez, A. M.; Greiner, J.
2001-01-01
Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries. PMID:11553801
Brügmann, B; Ghez, A M; Greiner, J
2001-09-11
Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.
Model of Decaying Dark Energy Based on the Kaluza-Klein Theory
NASA Astrophysics Data System (ADS)
Zakirov, U. N.
2017-08-01
On the basis of a scalar potential associated with Beltrami's geometry - manifolds of constant negative curvature, the Klein-Gordon problem has been solved, making it possible, under the assumption of a physical structure of the fifth dimension (presumably a rich form of matter), to model on the basis of the Kaluza-Klein theory the hypothesis of decaying dark energy configuring the rates of expansion of the Universe.
Perturbations of near-horizon geometries and instabilities of Myers-Perry black holes
NASA Astrophysics Data System (ADS)
Durkee, Mark N.; Reall, Harvey S.
2011-05-01
It is shown that the equations governing linearized gravitational (or electromagnetic) perturbations of the near-horizon geometry of any known extreme vacuum black hole (allowing for a cosmological constant) can be Kaluza-Klein reduced to give the equation of motion of a charged scalar field in AdS2 with an electric field. One can define an effective Breitenlöhner-Freedman bound for such a field. We conjecture that if a perturbation preserves certain symmetries then a violation of this bound should imply an instability of the full black hole solution. Evidence in favor of this conjecture is provided by the extreme Kerr solution and extreme cohomogeneity-1 Myers-Perry solution. In the latter case, we predict an instability in seven or more dimensions and, in five dimensions, we present results for operator conformal weights assuming the existence of a conformal field theory dual. We sketch a proof of our conjecture for scalar field perturbations.
NASA Astrophysics Data System (ADS)
García-Jiménez, I.; Novales-Sánchez, H.; Toscano, J. J.
2016-05-01
One-loop Standard Model observables produced by virtual heavy Kaluza-Klein fields play a prominent role in the minimal model of universal extra dimensions. Motivated by this aspect, we integrate out all the Kaluza-Klein heavy modes coming from the Yang-Mills theory set on a spacetime with an arbitrary number, n , of compact extra dimensions. After fixing the gauge with respect to the Kaluza-Klein heavy gauge modes in a covariant manner, we calculate a gauge-independent effective Lagrangian expansion containing multiple Kaluza-Klein sums that entail a bad divergent behavior. We use the Epstein-zeta function to regularize and characterize discrete divergences within such multiple sums, and then we discuss the interplay between the number of extra dimensions and the degree of accuracy of effective Lagrangians to generate or not divergent terms of discrete origin. We find that nonrenormalizable terms with mass dimension k are finite as long as k >4 +n . Multiple Kaluza-Klein sums of nondecoupling logarithmic terms, not treatable by Epstein-zeta regularization, are produced by four-dimensional momentum integration. On the grounds of standard renormalization, we argue that such effects are unobservable.
NASA Astrophysics Data System (ADS)
Luminet, Jean-Pierre
1992-09-01
Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.
Einstein-Yang-Mills-Dirac systems from the discretized Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
Wali, Kameshwar; Viet, Nguyen Ali
2017-01-01
A unified theory of the non-Abelian gauge interactions with gravity in the framework of a discretized Kaluza-Klein theory is constructed with a modified Dirac operator and wedge product. All the couplings of chiral spinors to the non-Abelian gauge fields emerge naturally as components of the coupling of the chiral spinors in the generalized gravity together with some new interactions. In particular, the currently prevailing gravity-QCD quark and gravity-electroweak-quark and lepton models are shown to follow as special cases of the general framework.
Kaluza-Klein cosmology from five-dimensional Lovelock-Cartan theory
NASA Astrophysics Data System (ADS)
Castillo-Felisola, Oscar; Corral, Cristóbal; del Pino, Simón; Ramírez, Francisca
2016-12-01
We study the Kaluza-Klein dimensional reduction of the Lovelock-Cartan theory in five-dimensional spacetime, with a compact dimension of S1 topology. We find cosmological solutions of the Friedmann-Robertson-Walker class in the reduced spacetime. The torsion and the fields arising from the dimensional reduction induce a nonvanishing energy-momentum tensor in four dimensions. We find solutions describing expanding, contracting, and bouncing universes. The model shows a dynamical compactification of the extra dimension in some regions of the parameter space.
Non-Abelian gauge fields as components of gravity in the discretized Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
Nguyen, Ai Viet; Pham, Tien Du
2017-06-01
Discretized Kaluza-Klein theory in ℳ2 × Z 2 spacetime can be constructed based on the concepts of noncommutative geometry. In this paper, we show that it is possible to incorporate the non-Abelian gauge fields in this framework. The generalized Hilbert-Einstein action is gauge invariant only in two cases. In the first case, the gauge group must be Abelian on one sheet of spacetime and non-Abelian on the other one. In the second case, the gauge group must be the same on two sheets of spacetime. Actually, the theories of electroweak and strong interactions can fit into these two cases.
New Kaluza-Klein instantons and the decay of AdS vacua
NASA Astrophysics Data System (ADS)
Ooguri, Hirosi; Spodyneiko, Lev
2017-07-01
We construct a generalization of Witten's Kaluza-Klein instanton, where a higher-dimensional sphere (rather than a circle as in Witten's instanton) collapses to zero size and the geometry terminates at a bubble of nothing, in a low energy effective theory of M theory. We use the solution to exhibit the instability of nonsupersymmetric AdS5 vacua in M theory compactified on positive Kähler-Einstein spaces, providing further evidence for the recent conjecture that any nonsupersymmetric anti-de Sitter vacuum supported by fluxes must be unstable.
Graviton Kaluza-Klein modes in nonflat branes with stabilized modulus
NASA Astrophysics Data System (ADS)
Paul, Tanmoy; SenGupta, Soumitra
2016-04-01
We consider a generalized two brane Randall-Sundrum model where the branes are endowed with nonzero cosmological constant. In this scenario, we re-examine the modulus stabilization mechanism and the nature of Kaluza-Klein (KK) graviton modes. Our result reveals that while the KK mode graviton masses may change significantly with the brane cosmological constant, the Goldberger-Wise stabilization mechanism, which assumes a negligible backreaction on the background metric, continues to hold even when the branes have a large cosmological constant. The possibility of having a global minimum for the modulus is also discussed. Our results also include an analysis for the radion mass in this nonflat brane scenario.
Compact hyperbolic extra dimensions: branes, kaluza-klein modes, and cosmology
Kaloper; March-Russell; Starkman; Trodden
2000-07-31
We reconsider theories with low gravitational (or string) scale M(*) where Newton's constant is generated via new large-volume spatial dimensions, while standard model states are localized to a 3-brane. Utilizing compact hyperbolic manifolds we show that the spectrum of Kaluza-Klein modes is radically altered. This allows the early Universe to evolve normally up to substantial temperatures, and completely negates the astrophysical constraints on M(*). Furthermore, an exponential hierarchy between the usual Planck scale and the true fundamental scale of physics can emerge with only O(1) coefficients. The linear size of the internal space remains small. The proposal has striking testable signatures.
Schwinger pair creation of Kaluza-Klein particles: Pair creation without tunneling
Friedmann, Tamar; Verlinde, Herman
2005-03-15
We study Schwinger pair creation of charged Kaluza-Klein (KK) particles from a static KK electric field. We find that the gravitational backreaction of the electric field on the geometry--which is incorporated via the electric KK-Melvin solution--prevents the electrostatic potential from overcoming the rest mass of the KK particles, thus impeding the tunneling mechanism which is often thought of as responsible for the pair creation. However, we find that pair creation still occurs with a finite rate formally similar to the classic Schwinger result, but via an apparently different mechanism, involving a combination of the Unruh effect and vacuum polarization due to the E-field.
Light Kaluza Klein States in Randall-Sundrum Models with Custodial SU(2)
Carena, Marcela; Ponton, Eduardo; Santiago, Jose; Wagner, Carlos E.M.; /Argonne /Chicago U., EFI /KICP, Chicago
2006-07-01
We consider Randall-Sundrum scenarios based on SU(2){sub L} x SU(2){sub R} and a discrete parity exchanging L with R. The custodial and parity symmetries can be used to make the tree level contribution to the T parameter and the anomalous couplings of the bottom quark to the Z very small. We show that the resulting quantum numbers typically induce a negative T parameter at one loop that, together with the positive value of the S parameter, restrict considerably these models. There are nevertheless regions of parameter space that successfully reproduce the fit to electroweak precision observables with light Kaluza-Klein excitations accessible at colliders. We consider models of gauge-Higgs unification that implement the custodial and parity symmetries and find that the electroweak data singles out a very well defined region in parameter space. In this region one typically finds light gauge boson Kaluza-Klein excitations as well as light SU(2){sub L} singlet, and sometimes also doublet, fermionic states, that mix with the top quark, and that may yield interesting signatures at future colliders.
Testing a possible way of geometrization of the strong interaction by a Kaluza-Klein star
NASA Astrophysics Data System (ADS)
Karsai, Szilvia; Pósfay, Péter; Barnaföldi, Gergely Gábor; Lukács, Béla
2016-10-01
Geometrization of the fundamental interactions has been extensively studied during the century. The idea of introducing compactified spatial dimensions originated by Kaluza and Klein. Following their approach, several model were built representing quantum numbers (e.g. charges) as compactified space-time dimensions. Such geometrized theoretical descriptions of the fundamental interactions might lead us to get closer to the unification of the principle theories. Here, we apply a 3 + 1C + 1 dimensional theory, which contains one extra compactified spatial dimension 1C in connection with the flavor quantum number in Quantum Chromodynamics. Within our model the size of the 1C dimension is proportional to the inverse mass-difference of the first low-mass baryon states. We used this phenomena to apply in a compact star model — a natural laboratory for testing the theory of strong interaction and the gravitational theory in parallel. Our aim is to test the modification of the measurable macroscopical parameters of a compact Kaluza-Klein star by varying the size of the compactified extra dimension. Since larger the RC the smaller the mass difference between the first spokes of the Kaluza-Klein ladder resulting smaller-mass stars. Using the Tolman-Oppenheimer-Volkov equation, we investigate the M-R diagram and the dependence of the maximum mass of compact stars. Besides testing the validity of our model we compare our results to the existing observational data of pulsar properties for constraints.
Testing a Possible way of Geometrization of the Strong Interaction by a Kaluza -- Klein Star
NASA Astrophysics Data System (ADS)
Karsai, Szilvia; Pósfay, Péter Barnaföldi, Gergely Gábor Lukács, Béla
Geometrization of the fundamental interactions has been extensively studied during the century. The idea of introducing compactified spatial dimensions originated by Kaluza and Klein. Following their approach, several model were built representing quantum numbers (e.g. charges) as compactified space-time dimensions. Such geometrized theoretical descriptions of the fundamental interactions might lead us to get closer to the unification of the principle theories. Here, we apply a 3 + 1C + 1 dimensional theory, which contains one extra compactified spatial dimension 1C in connection with the flavor quantum number in Quantum Chromodynamics. Within our model the size of the 1C dimension is proportional to the inverse mass-difference of the first low-mass baryon states. We used this phenomena to apply in a compact star model -- a natural laboratory for testing the theory of strong interaction and the gravitational theory in parallel. Our aim is to test the modification of the measurable oscopical parameters of a compact Kaluza -- Klein star by varying the size of the compactified extra dimension. Since larger the RC the smaller the mass difference between the first spokes of the Kaluza -- Klein ladder resulting smaller-mass stars. Using the Tolman -- Oppenheimer -- Volkov equation, we investigate the M-R diagram and the dependence of the maximum mass of compact stars. Besides testing the validity of our model we compare our results to the existing observational data of pulsar properties for constraints.
Cosmological rotating black holes in five-dimensional fake supergravity
Nozawa, Masato; Maeda, Kei-ichi
2011-01-15
In recent series of papers, we found an arbitrary dimensional, time-evolving, and spatially inhomogeneous solution in Einstein-Maxwell-dilaton gravity with particular couplings. Similar to the supersymmetric case, the solution can be arbitrarily superposed in spite of nontrivial time-dependence, since the metric is specified by a set of harmonic functions. When each harmonic has a single point source at the center, the solution describes a spherically symmetric black hole with regular Killing horizons and the spacetime approaches asymptotically to the Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology. We discuss in this paper that in 5 dimensions, this equilibrium condition traces back to the first-order 'Killing spinor' equation in 'fake supergravity' coupled to arbitrary U(1) gauge fields and scalars. We present a five-dimensional, asymptotically FLRW, rotating black-hole solution admitting a nontrivial 'Killing spinor', which is a spinning generalization of our previous solution. We argue that the solution admits nondegenerate and rotating Killing horizons in contrast with the supersymmetric solutions. It is shown that the present pseudo-supersymmetric solution admits closed timelike curves around the central singularities. When only one harmonic is time-dependent, the solution oxidizes to 11 dimensions and realizes the dynamically intersecting M2/M2/M2-branes in a rotating Kasner universe. The Kaluza-Klein-type black holes are also discussed.
Noncommutative D{sub 3}-brane, black holes, and attractor mechanism
Kar, Supriya; Majumdar, Sumit
2006-09-15
We revisit the 4D generalized black hole geometries, obtained by us 14, with a renewed interest, to unfold some aspects of effective gravity in a noncommutative D{sub 3}-brane formalism. In particular, we argue for the existence of extra dimensions in the gravity decoupling limit in the theory. We show that the theory is rather described by an ordinary geometry and is governed by an effective string theory in 5D. The extremal black hole geometry AdS{sub 5} obtained in effective string theory is shown to be in precise agreement with the gravity dual proposed for D{sub 3}-brane in a constant magnetic field. Kaluza-Klein compactification is performed to obtain the corresponding charged black hole geometries in 4D. Interestingly, they are shown to be governed by the extremal black hole geometries known in string theory. The attractor mechanism is exploited in effective string theory underlying a noncommutative D{sub 3}-brane and the macroscopic entropy of a charged black hole is computed. We show that the generalized black hole geometries in a noncommutative D{sub 3}-brane theory are precisely identical to the extremal black holes known in 4D effective string theory.
Born-Infeld action and Chern-Simons term from Kaluza-Klein monopole in M-theory
NASA Astrophysics Data System (ADS)
Imamura, Yosuke
1997-11-01
We investigate the zero modes of the Kaluza-Klein monopole in M-theory and show that the Born-Infeld action and the Chern-Simons term of a D6-brane are reproduced to quadratic order in the field strength of the U(1) field on the brane.
Black hole merger estimates in Einstein-Maxwell and Einstein-Maxwell-dilaton gravity
NASA Astrophysics Data System (ADS)
Jai-akson, Puttarak; Chatrabhuti, Auttakit; Evnin, Oleg; Lehner, Luis
2017-08-01
The recent birth of gravitational wave astronomy invites a new generation of precision tests of general relativity. Signatures of black hole (BH) mergers must be systematically explored in a wide spectrum of modified gravity theories. Here, we turn to one such theory in which the initial value problem for BH mergers is well posed, the Einstein-Maxwell-dilaton system. We present conservative estimates for the merger parameters (final spins, quasinormal modes) based on techniques that have worked well for ordinary gravity mergers and utilize information extracted from test particle motion in the final BH metric. The computation is developed in parallel for the modified gravity BHs (we specifically focus on the Kaluza-Klein value of the dilaton coupling, for which analytic BH solutions are known) and ordinary Kerr-Newman BHs. We comment on the possibility of obtaining final BHs with spins consistent with current observations.
On Hamiltonians with position-dependent mass from Kaluza-Klein compactifications
NASA Astrophysics Data System (ADS)
Ballesteros, Ángel; Gutiérrez-Sagredo, Iván; Naranjo, Pedro
2017-02-01
In a recent paper (Morris (2015) [1]), an inhomogeneous compactification of the extra dimension of a five-dimensional Kaluza-Klein metric has been shown to generate a position-dependent mass (PDM) in the corresponding four-dimensional system. As an application of this dimensional reduction mechanism, a specific static dilatonic scalar field has been connected with a PDM Lagrangian describing a well-known nonlinear PDM oscillator. Here we present more instances of this construction that lead to PDM systems with radial symmetry, and the properties of their corresponding inhomogeneous extra dimensions are compared with the ones in the nonlinear oscillator model. Moreover, it is also shown how the compactification introduced in this type of models can alternatively be interpreted as a novel mechanism for the dynamical generation of curvature.
Supersymmetric and Kaluza-Klein Particles Multiple Scattering in the Earth
Albuquerque, Ivone; Klein, Spencer
2009-05-19
Neutrino telescopes with cubic kilometer volume have the potential to discover new particles. Among them are next to lightest supersymmetric (NLSPs) and next to lightest Kaluza-Klein (NLKPs) particles. Two NLSPs or NLKPs will transverse the detector simultaneously producing parallel charged tracks. The track separation inside the detector can be a few hundred meters. As these particles might propagate a few thousand kilometers before reaching the detector, multiple scattering could enhance the pair separation at the detector. We find that the multiple scattering will alter the separation distribution enough to increase the number of NLKP pairs separated by more than 100 meters (a reasonable experimental cut) by up to 46% depending on the NLKP mass. Vertical upcoming NLSPs will have their separation increased by 24% due to multiple scattering.
Kaluza-Klein masses in nonprime orbifolds: Z{sub 12-I} compactification and threshold correction
Kim, Jihn E.; Kyae, Bumseok
2008-05-15
Analyzing the one-loop partition function, we discuss possible Kaluza-Klein (KK) states in the orbifold compactification of the heterotic string theory, toward the application to the threshold correction. The KK massive states associated with (relatively) large extra dimensions can arise only in nonprime orbifolds. The Gliozzi-Scherk-Olive (GSO) projection condition by a shift vector V{sup I} is somewhat relaxed above the compactification scale 1/R. We also present the other condition on Wilson line W, P{center_dot}W=integer. With the knowledge of the partition function, we obtain the threshold corrections to gauge couplings, which include the Wilson line effects. We point out the differences in string and field theoretic orbifolds.
Next-to-leading order gravitational spin1-spin2 coupling with Kaluza-Klein reduction
Levi, Michele
2010-09-15
We use the recently proposed Kaluza-Klein (KK) reduction over the time dimension, within an effective field theory (EFT) approach, to calculate the next-to-leading order gravitational spin1-spin2 interaction between two spinning compact objects. It is shown here that to next-to-leading order in the spin1-spin2 interaction, the reduced KK action within the stationary approximation is sufficient to describe the gravitational interaction, and that it simplifies calculation substantially. We also find here that the gravitomagnetic vector field defined within the KK decomposition of the metric mostly dominates the mediation of the interaction. Our results coincide with those calculated in the Arnowitt-Deser-Misner Hamiltonian formalism, and we provide another explanation for the discrepancy with the result previously derived within the EFT approach, thus demonstrating clearly the equivalence of the Arnowitt-Deser-Misner Hamiltonian formalism and the EFT action approach.
Kaluza-Klein/Z's Differentiation at the LHC and Linear Collider
Rizzo, Thomas G.
2003-05-06
We explore the capabilities of the LHC and the Linear Collider (LC) to distinguish the production of Kaluza-Klein (KK) excitations from an ordinary Z{prime} within the context of theories with TeV scale extra dimensions. At the LHC, these states are directly produced in the Drell-Yan channel while at the LC the effects of their exchanges are indirectly felt as new contact interactions in processes such as e{sup +}e{sup -} {yields} f{bar f}. While we demonstrate that the LC is somewhat more capable at KK/Z{prime} differentiation than is the LHC, the simplest LC analysis relies upon the LHC data for the resonance mass as an important necessary input.
Constraints on the size of the extra dimension from Kaluza-Klein gravitino decay
Gherson, David
2007-08-15
We study the consequences of the gravitino decay into dark matter. We suppose that the lightest neutralino is the main component of dark matter. In our framework the gravitino is heavy enough to decay before big bang nucleosynthesis starts. We consider a model coming from a five dimensional supergravity compactified on S{sup 1}/Z{sub 2} with gravity in the bulk and matter localized on tensionless branes at the orbifold fixed points. We require that the dark matter, which is produced thermally and in the decay of Kaluza-Klein modes of the gravitino, has an abundance compatible with observation. We deduce from our model that there are curves of constraints between the size of the extra dimension and the reheating temperature of the Universe after inflation.
Das, Prasanta Kumar; Satheeshkumar, V. H.; Suresh, P. K.
2008-09-15
In the large extra dimensional Kaluza-Klein (KK) scenario, where the usual standard model (SM) matter is confined to a 3+1-dimensional hypersurface called the 3-brane and gravity can propagate to the bulk (D=4+d, d being the number of extra spatial dimensions), the light graviton KK modes can be produced inside the supernova core due to the usual nucleon-nucleon bremstrahlung, electron-positron, and photon-photon annihilations. This photon inside the supernova becomes a plasmon due to the plasma effect. In this paper, we study the energy-loss rate of SN 1987A due to the KK gravitons produced from the plasmon-plasmon annihilation. We find that the SN 1987A cooling rate leads to the conservative bound M{sub D}>22.9 TeV and 1.38 TeV for the case of two and three spacelike extra dimensions.
Significant effects of second Kaluza-Klein particles on dark matter physics
Kakizaki, Mitsuru; Senami, Masato; Matsumoto, Shigeki; Sato, Yoshio
2005-06-15
We point out that Kaluza-Klein (KK) dark matter physics is drastically affected by second KK particles. In this work various interesting phenomena caused by the second KK modes are discussed. In particular, we reevaluate the annihilation cross section relevant to the thermal relic density of KK dark matter in universal extra dimension models. In these models, the first KK mode of a B boson is a viable dark matter candidate by virtue of KK parity. We demonstrate that the KK dark matter annihilation cross section can be enhanced, compared with the tree-level cross section mediated only by first KK particles. The mass of the first KK mode of the B boson consistent with the Wilkinson Microwave Anisotropy Probe observation is increased.
New supernova limit on large extra dimensions: bounds on Kaluza-Klein graviton production.
Hannestad, S; Raffelt, G G
2001-07-30
If large extra dimensions exist in nature, supernova (SN) cores will emit large fluxes of Kaluza-Klein gravitons, producing a cosmic background of these particles with energies and masses up to about 100 MeV. Radiative decays then give rise to a diffuse cosmic gamma-ray background with E(gamma) approximately less than 100 MeV which is well in excess of the observations if more than 0.5%-1% of the SN energy is emitted into the new channel. For two extra dimensions we derive a conservative bound on their radius of R approximately less than 0.9 x 10(-4) mm; for three extra dimensions it is R approximately less than 1.9 x 10(-7) mm.
Kaluza-Klein consistency, Killing vectors and Kähler spaces
NASA Astrophysics Data System (ADS)
Hoxha, P.; Martinez-Acosta, R. R.; Pope, C. N.
2000-10-01
We make a detailed investigation of all spaces Qn1...nNq1...qN of the form of U(1) bundles over arbitrary products ∏iCPni of complex projective spaces, with arbitrary winding numbers qi over each factor in the base. Special cases, including Q1111 (sometimes known as T11), Q111111 and Q2132, are relevant for compactifications of type IIB and D = 11 supergravity. Remarkable `conspiracies' allow consistent Kaluza-Klein S5, S4 and S7 sphere reductions of these theories that retain all the Yang-Mills fields of the isometry group in a massless truncation. We prove that such conspiracies do not occur for the reductions on the Qn1...nNq1...qN spaces, and that it is inconsistent to make a massless truncation in which the non-Abelian SU(ni + 1) factors in their isometry groups are retained. In the course of proving this we derive many properties of the spaces Qn1...nNq1...qN of more general utility. In particular, we show that they always admit Einstein metrics, and that the spaces where qi = (ni + 1)/l all admit two Killing spinors. We also obtain an iterative construction for real metrics on CPn, and construct the Killing vectors on Qn1...nNq1...qN in terms of scalar eigenfunctions on CPni. We derive bounds that allow us to prove that certain Killing-vector identities on spheres, necessary for consistent Kaluza-Klein reductions, are never satisfied on Qn1...nNq1...qN.
Kaluza-Klein Effects on Higgs Physics in Universal Extra Dimensions
Petriello, Frank J
2002-04-05
We examine the virtual effects of Kaluza-Klein (KK) states on Higgs physics in universal extra dimension models. We study the partial widths {Lambda}{sub h{yields}gg}, {Lambda}{sub h{yields}{gamma}{gamma}}, and {Lambda}{sub h{yields}{gamma}Z}, which are relevant for Higgs production and detection in future collider experiments. These interactions occur at one loop in the Standard Model, as do the KK contributions. We find that the deviations induced by the KK exchanges can be significant; for one extra dimension, the gg {yields} h production rate is increased by 10% - 85% for the mass of the first KK state in the range 500 {approx}> m{sub 1} {approx}> 1500 GeV, a region untested by current direct search and precision measurement constraints. The h {yields} {gamma}{gamma} decay width is decreased by {approx}< 20% in the same mass range. For two or more universal extra dimensions the results are cutoff dependent, and can only be qualitatively estimated. We comment on the detectability of these shifts at the LHC and at future e{sup +}e{sup -} and {gamma}{gamma} colliders.
Kaluza-Klein gluon + jets associated production at the Large Hadron Collider
NASA Astrophysics Data System (ADS)
Iyer, A. M.; Mahmoudi, F.; Manglani, N.; Sridhar, K.
2016-08-01
The Kaluza-Klein excitations of gluons offer the exciting possibility of probing bulk Randall-Sundrum (RS) models. In these bulk models either a custodial symmetry or a deformation of the metric away from AdS is invoked in order to deal with electroweak precision tests. Addressing both these models, we suggest a new channel in which to study the production of KK-gluons (gKK): one where it is produced in association with one or more hard jets. The cross-section for the gKK + jets channel is significant because of several contributing sub-processes. In particular, the 1-jet and the 2-jet associated processes are important because at these orders in QCD the qg and the gg initial states respectively come into play. We have performed a hadron-level simulation of the signal and present strategies to effectively extract the signal from what could potentially be a huge background. We present results for the kinematic reach of the LHC Run-II for different gKK masses in bulk-RS models.
Observability of gamma-ray spectral feature from Kaluza-Klein dark matter
NASA Astrophysics Data System (ADS)
Tsuchida, Satoshi; Mori, Masaki
2017-01-01
The theory of universal extra dimensions involves Kaluza-Klein (KK) particles. The lightest KK particle (LKP) is one of the good candidates for cold dark matter. Annihilation of LKP dark matter in the Galactic halo produces high-energy gamma-rays. The gamma-ray spectrum shows a characteristic peak structure around the LKP mass. This paper investigates the observability of this peak structure by present and near-future detectors taking account of their energy resolution, and calculates the expected count spectrum of the gamma-ray signal. Then, the maximum likelihood analysis is employed to judge whether the count spectrum contains the LKP signal. In the case where the signal is not detected, we set some constraints on the boost factor which is a product of the annihilation cross section relative to the thermal one and an uncertain factor dependent on the substructure of the LKP distribution in the Galactic halo. The constraints can be regarded as comparable with the results of analysis based on the HESS data. The observational data for the TeV or higher energy region are still limited, and the possible LKP signal is not conclusive. Thus, we expect near-future missions with better sensitivity will clarify whether the LKP dark matter should exist or not.
Kaluza-Klein Dark Matter: Direct Detection vis-a-vis LHC
Arrenberg, Sebastian; Baudis, Laura; Kong, Kyoungchul; Matchev, Konstantin T.; Yoo, Jonghee; /Fermilab
2008-11-01
We explore the phenomenology of Kaluza-Klein (KK) dark matter in very general models with universal extra dimensions (UEDs), emphasizing the complementarity between high-energy colliders and dark matter direct detection experiments. In models with relatively small mass splittings between the dark matter candidate and the rest of the (colored) spectrum, the collider sensitivity is diminished, but direct detection rates are enhanced. UEDs provide a natural framework for such mass degeneracies. We consider both 5-dimensional and 6-dimensional non-minimal UED models, and discuss the detection prospects for various KK dark matter candidates: the KK photon {gamma}{sub 1} (5D) the KK Z-boson Z{sub 1} (5D) and the spinless KK photon {gamma}{sub H} (6D). We combine collider limits such as electroweak precision data and expected LHC reach, with cosmological constraints from WMAP and the sensitivity of current or planned direct detection experiments. Allowing for general mass splittings, we show that neither colliders, nor direct detection experiments by themselves can explore all of the relevant KK dark matter parameter space. Nevertheless, they probe different parameter space regions and the combination of the two types of constraints can be quite powerful. For example, in the case of {gamma}{sub 1} in 5D UEDs the relevant parameter space will be almost completely covered by the combined LHC and direct detection sensitivities expected in the near future.
Search for Kaluza-Klein gravitons in extra dimension models via forward detectors at the LHC
NASA Astrophysics Data System (ADS)
Cho, Gi-Chol; Kono, Takanori; Mawatari, Kentarou; Yamashita, Kimiko
2015-06-01
We investigate contributions of Kaluza-Klein (KK) graviton in extra dimension models to the process p p →p γ p →p γ j X , where a proton emits a quasireal photon and is detected by using the very forward detectors planned at the LHC. In addition to the γ q initial state as in the Compton scattering in the standard model, the γ g scattering contributes through the t -channel exchange of KK gravitons. Taking account of pileup contributions to the background and examining viable kinematical cuts, constraints on the parameter space of both the ADD (Arkani-Hamed, Dimopoulos and Dvali) model and the RS (Randall and Sundrum) model are studied. With 200 fb-1 data at a center-of-mass energy of 14 TeV, the expected lower bound on the cutoff scale for the ADD model is 6.3 TeV at 95% confidence level, while a lower limit of 2.0 (0.5) TeV is set on the mass of the first excited graviton with the coupling parameter k /M¯ Pl=0.1 (0.01 ) for the RS model.
Lightest Kaluza-Klein graviton mode in a back-reacted Randall-Sundrum scenario
NASA Astrophysics Data System (ADS)
Das, Ashmita; SenGupta, Soumitra
2016-08-01
In search of the extra dimensions in the ongoing LHC experiments, the signatures of the Randall-Sundrum (RS) lightest KK graviton have been in the main focus in recent years. The recent data from the dilepton decay channel at the LHC has determined the experimental lower bound on the mass of the RS lightest Kaluza-Klein (KK) graviton for different choices of the underlying parameters of the theory. In this work we explore the effects of the back-reaction of the bulk scalar field, which is employed to stabilise the RS model, in modifying the couplings of the lightest KK graviton with the standard model matter fields located on the visible brane. In such a modified background geometry we show that the coupling of the lightest KK graviton with the SM matter fields gets a significant suppression due to the inclusion of the back-reaction of the bulk stabilising scalar field. This implies that the back-reaction parameter weakens the signals from the RS scenario in collider experiments, which in turn explains the non-visibility of KK graviton in colliders. Thus we show that the modulus stabilisation plays a crucial role in the search of warped extra dimensions in collider experiments.
Gravitational Kaluza-Klein modes in the string-cigar braneworld
NASA Astrophysics Data System (ADS)
Veras, D. F. S.; Silva, J. E. G.; Cruz, W. T.; Almeida, C. A. S.
2015-03-01
In this work we analyze the properties of the gravitational Kaluza-Klein (KK) modes in two stringlike braneworlds, the thin Gherghetta-Shaposhnikov (GS) model and the thick string-cigar model. The string-cigar model is a smooth generalization of the GS model that undergoes a Ricci geometrical flow. We find a new massless mode in both models satisfying the respective Schrödinger equations. By means of a numerical analysis, we obtain the complete graviton spectrum and its respective eigenfunctions. The KK spectrum exhibits the usual linear regime for large discrete index n and we find a new decreasing regime for small n . Moreover, there is an asymmetric mass gap between the massless mode and the massive KK tower. The mass gap in the GS model is bigger than in the string-cigar model. In addition, the mass gap remains invariant upon the geometrical flow. It turns out that in the string-cigar model the brane structure smoothes and amplifies the KK modes near the brane core. The presence of a potential well in the string-cigar scenario allows the existence of resonant massive gravitons for small masses.
Kaluza-Klein dark matter: Direct detection vis-a-vis CERN LHC
Arrenberg, Sebastian; Baudis, Laura; Kong, Kyoungchul; Matchev, Konstantin T.; Yoo, Jonghee
2008-09-01
We explore the phenomenology of Kaluza-Klein (KK) dark matter in very general models with universal extra dimensions (UEDs), emphasizing the complementarity between high-energy colliders and dark matter direct detection experiments. In models with relatively small mass splittings between the dark matter candidate and the rest of the (colored) spectrum, the collider sensitivity is diminished, but direct detection rates are enhanced. UEDs provide a natural framework for such mass degeneracies. We consider both five-dimensional and six-dimensional nonminimal UED models, and discuss the detection prospects for various KK dark matter candidates: the KK photon {gamma}{sub 1}, the KK Z boson Z{sub 1}, the KK Higgs boson H{sub 1}, and the spinless KK photon {gamma}{sub H}. We combine collider limits, such as electroweak precision data and expected LHC reach, with cosmological constraints from WMAP, and the sensitivity of current or planned direct detection experiments. Allowing for general mass splittings, we show that neither colliders nor direct detection experiments by themselves can explore all of the relevant KK dark matter parameter space. Nevertheless, they probe different parameter space regions, and the combination of the two types of constraints can be quite powerful. For example, in the case of {gamma}{sub 1} in 5D UEDs the relevant parameter space will be almost completely covered by the combined CERN LHC and direct detection sensitivities expected in the near future.
Testing extra dimensions below the production threshold of Kaluza-Klein excitations
Boos, Edward E.; Bunichev, Viacheslav E.; Smolyakov, Mikhail N.; Volobuev, Igor P.
2009-05-15
We consider a stabilized Randall Sundrum 1 model in the energy range below the direct production of Kaluza-Klein (KK) states. In this range, we work out the effective Lagrangian due to exchange of heavy KK tensor graviton and scalar radion states and compute explicitly the corresponding effective coupling constants. As an example, the Drell-Yan lepton pair production at the Tevatron and the LHC is analyzed in two situations, when the first KK resonance is too heavy to be directly detected at the colliders, and when the first KK resonance is visible, but other states are still too heavy. It is shown that in both cases the contribution from the KK invisible tower leads to a modification of final particles distributions. In particular, for the second case a nontrivial interference between the first KK mode and the rest KK tower takes place. Expected 95% C.L. limits for model parameters for the Tevatron and the LHC are given. In the Appendix, useful formulas for the cross sections and distributions of various new 2{yields}2 processes via heavy KK tower exchange are presented, the new formulas containing nonzero particle masses for final state fermions and bosons. The formulas and numerical results are obtained by means of the CompHEP code, in which all new effective interactions are implemented providing a tool for simulation of corresponding events and a more detailed analysis.
Kaluza-Klein gravitons are negative energy dust in brane cosmology
Minamitsuji, Masato; Sasaki, Misao; Langlois, David
2005-04-15
We discuss the effect of Kaluza-Klein (KK) modes of bulk metric perturbations on the second Randall-Sundrum (RS II) type brane cosmology, taking the possible backreaction in the bulk and on the brane into account. KK gravitons may be produced via quantum fluctuations during a de Sitter (dS) inflating phase of our brane universe. In an effective 4-dimensional theory in which one integrates out the extra-dimensional dependence in the action, KK gravitons are equivalent to massive gravitons on the brane with masses m>3H/2, where H represents the expansion rate of a dS brane. Thus production of even a tiny amount of KK gravitons may eventually have a significant impact on the late-time brane cosmology. As a first step to quantify the effect of KK gravitons on the brane, we calculate the effective energy density and pressure for a single KK mode. Surprisingly, we find that a KK mode behaves as cosmic dust with a negative energy density on the brane. We note that the bulk energy density of a KK mode is positive definite and there occurs no singular phenomenon in the bulk.
Dangerous angular Kaluza-Klein/glueball relics in string theory cosmology
Dufaux, J. F.; Kofman, L.; Peloso, M.
2008-07-15
The presence of Kaluza-Klein (KK) particles in the universe is a potential manifestation of string theory cosmology. In general, they can be present in the high temperature bath of the early universe. In particular examples, string theory inflation often ends with brane-antibrane annihilation followed by the energy cascading through massive closed string loops to KK modes which then decay into lighter standard model particles. However, massive KK modes in the early universe may become dangerous cosmological relics if the inner manifold contains warped throat(s) with approximate isometries. In the complimentary picture, in the AdS/CFT dual gauge theory with extra isometries, massive glueballs of various spins become the dangerous cosmological relics. The decay of these angular KK modes/glueballs, located around the tip of the throat, is caused by isometry breaking which results from gluing the throat to the compact Calabi-Yau (CY) manifold. We address the problem of these angular KK particles/glueballs, studying their interactions and decay channels, from the theory side, and the resulting cosmological constraints on the warped compactification parameters, from the phenomenology side. The abundance and decay time of the long-lived nonrelativistic angular KK modes depend strongly on the parameters of the warped geometry, so that observational constraints rule out a significant fraction of the parameter space. In particular, the coupling of the angular KK particles can be weaker than gravitational.
PAMELA and Fermi LAT signals from long-lived Kaluza-Klein dark matter
Okada, Nobuchika; Yamada, Toshifumi
2009-10-01
We propose a simple extension of the minimal universal extra dimension model by introducing a small curvature. The model is formulated as a small anti-de Sitter curvature limit of the five-dimensional standard model (SM) in the Randall-Sundrum background geometry. While the lightest Kaluza-Klein (KK) particle can be thermal relic dark matter as usual in the universal extra dimension model, the KK parity is explicitly broken in the presence of the small curvature and the KK dark matter decays into the SM fermions with a long lifetime. Couplings of the KK dark matter with SM fermion pairs in the five-dimensional bulk are controlled by fermion bulk masses. By tuning bulk masses of quarks, we can suppress KK dark matter decay into quarks. With a suitable choice of bulk masses for leptons, KK dark matter decay into leptons can account for the cosmic-ray electron/positron excesses reported by the recent PAMELA and Fermi LAT satellite experiments.
Integration of Kaluza-Klein modes in Yang-Mills theories
Novales-Sanchez, H.; Toscano, J. J.
2011-10-01
A five-dimensional pure Yang-Mills theory, with the fifth coordinate compactified on the orbifold S{sup 1}/Z{sub 2} of radius R, leads to a four-dimensional theory which is governed by two types of infinitesimal gauge transformations, namely, the well-known standard gauge transformations (SGT) dictated by the SU{sub 4}(N) group under which the zero Fourier modes A{sub {mu}}{sup (0)a} transform as gauge fields, and a set of nonstandard gauge transformations (NSGT) determining the gauge nature of the Kaluza-Klein (KK) excitations A{sub {mu}}{sup (m)a}. By using a SGT-covariant gauge-fixing procedure for removing the degeneration associated with the NSGT, we integrate out the KK excitations and obtain a low-energy effective Lagrangian expansion involving all of the independent canonical-dimension-six operators that are invariant under the SGT of the SU{sub 4}(N) group and that are constituted by light gauge fields, A{sub {mu}}{sup (0)a}, exclusively. It is shown that this effective Lagrangian is invariant under the SGT, but it depends on the gauge-fixing of the gauge KK excitations. Our result shows explicitly that the one-loop contributions of the KK excitations to light (standard) Green's functions are renormalizable.
Kaluza-Klein cosmological model in f(R, T) gravity with Λ(T)
NASA Astrophysics Data System (ADS)
Sahoo, P. K.; Mishra, B.; Tripathy, S. K.
2016-04-01
A class of Kaluza-Klein cosmological models in $f(R,T)$ theory of gravity have been investigated. In the work, we have considered the functional $f(R,T)$ to be in the form $f(R,T)=f(R)+f(T)$ with $f(R)=\\lambda R$ and $f(T)=\\lambda T$. Such a choice of the functional $f(R,T)$ leads to an evolving effective cosmological constant $\\Lambda$ which depends on the stress energy tensor. The source of the matter field is taken to be a perfect cosmic fluid. The exact solutions of the field equations are obtained by considering a constant deceleration parameter which leads two different aspects of the volumetric expansion namely a power law and an exponential volumetric expansion. Keeping an eye on the accelerating nature of the universe in the present epoch, the dynamics and physical behaviour of the models have been discussed. From statefinder diagnostic pair we found that the model with exponential volumetric expansion behaves more like a $\\Lambda$CDM model.
Hamiltonian Map to Conformal Modification of Spacetime Metric: Kaluza-Klein and TeVeS
NASA Astrophysics Data System (ADS)
Horwitz, Lawrence; Gershon, Avi; Schiffer, Marcelo
2011-01-01
It has been shown that the orbits of motion for a wide class of non-relativistic Hamiltonian systems can be described as geodesic flows on a manifold and an associated dual by means of a conformal map. This method can be applied to a four dimensional manifold of orbits in spacetime associated with a relativistic system. We show that a relativistic Hamiltonian which generates Einstein geodesics, with the addition of a world scalar field, can be put into correspondence in this way with another Hamiltonian with conformally modified metric. Such a construction could account for part of the requirements of Bekenstein for achieving the MOND theory of Milgrom in the post-Newtonian limit. The constraints on the MOND theory imposed by the galactic rotation curves, through this correspondence, would then imply constraints on the structure of the world scalar field. We then use the fact that a Hamiltonian with vector gauge fields results, through such a conformal map, in a Kaluza-Klein type theory, and indicate how the TeVeS structure of Bekenstein and Saunders can be put into this framework. We exhibit a class of infinitesimal gauge transformations on the gauge fields {mathcal{U}}_{μ}(x) which preserve the Bekenstein-Sanders condition {mathcal{U}}_{μ}{mathcal{U}}^{μ}=-1. The underlying quantum structure giving rise to these gauge fields is a Hilbert bundle, and the gauge transformations induce a non-commutative behavior to the fields, i.e. they become of Yang-Mills type. Working in the infinitesimal gauge neighborhood of the initial Abelian theory we show that in the Abelian limit the Yang-Mills field equations provide residual nonlinear terms which may avoid the caustic singularity found by Contaldi et al.
NASA Astrophysics Data System (ADS)
Qiang, Li-E.; Zhao, Shu Hong; Xu, Peng
2016-12-01
Gravitational waves from coalescing black-hole binaries (BHBs) were recently observed by the advanced LIGO detectors. Based on the perturbation analysis, for general Kaluza-Klein theories with compact extra dimensions, we find a 1st-order post-Newtonian correction to the inspiral gravitational waveforms of black-hole binaries, that comes from the variations of the volume of the extra dimensions in near source zones. Such correction depends on a new parameter χ=\\frac{n}{2+n} with n the dimensionality of the extra space and it is irrelevant to the particular choice of the topology of the extra space. For the ideal case of a black-hole binary system following nearly circular orbital motion with almost equal or intermediate mass ratio, such higher-dimensional corrections to the chirping amplitude are worked out. Giving the power of tracing inspiral waves from coalescing massive BHBs with high signal-to-noise ratios, the planned space-borne antennas such as the eLISA and DECIGO may give us a measurement of the parameter χ in the near future and may serve us as new probes in the searching for the evidence of the hidden compact dimensions.
IceCube Collaboration; Abbasi, R.; al., et
2009-10-23
A search for muon neutrinos from Kaluza-Klein dark matter annihilations in the Sun has been performed with the 22-string configuration of the IceCube neutrino detector using data collected in 104.3 days of live-time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured lightest Kaluza-Klein particle (LKP) WIMPs in the Sun and converted to limits on the LKP-proton cross-sections for LKP masses in the range 250 - 3000 GeV. These results are the most stringent limits to date on LKP annihilation in the Sun.
NASA Astrophysics Data System (ADS)
Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Botner, O.; Bradley, L.; Braun, J.; Breder, D.; Carson, M.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cohen, S.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Day, C. T.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hasegawa, Y.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lucke, A.; Lundberg, J.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; McParland, C. P.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Miyamoto, H.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Patton, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Potthoff, N.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Terranova, C.; Tilav, S.; Toale, P. A.; Tooker, J.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wiedemann, A.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; IceCube Collaboration
2010-03-01
A search for muon neutrinos from Kaluza-Klein dark matter annihilations in the Sun has been performed with the 22-string configuration of the IceCube neutrino detector using data collected in 104.3 days of live time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured lightest Kaluza-Klein particle (LKP) WIMPs in the Sun and converted to limits on the LKP-proton cross sections for LKP masses in the range 250-3000 GeV. These results are the most stringent limits to date on LKP annihilation in the Sun.
Einstein Gravity and Beyond: Aspects of Higher-Curvature Gravity and Black Holes
NASA Astrophysics Data System (ADS)
Chatterjee, Saugata
This thesis explores the different aspects of higher curvature gravity. The "membrane paradigm" of black holes in Einstein gravity is extended to black holes in f(R) gravity and it is shown that the higher curvature effects of f( R) gravity causes the membrane fluid to become non-Newtonian. Next a modification of the null energy condition in gravity is provided. The purpose of the null energy condition is to filter out ill-behaved theories containing ghosts. Conformal transformations, which are simple redefinitions of the spacetime, introduces serious violations of the null energy condition. This violation is shown to be spurious and a prescription for obtaining a modified null energy condition, based on the universality of the second law of thermodynamics, is provided. The thermodynamic properties of the black holes are further explored using merger of extremal black holes whose horizon entropy has topological contributions coming from the higher curvature Gauss-Bonnet term. The analysis refutes the prevalent belief in the literature that the second law of black hole thermodynamics is violated in the presence of the Gauss-Bonnet term in four dimensions. Subsequently a specific class of higher derivative scalar field theories called the galileons are obtained from a Kaluza-Klein reduction of Gauss-Bonnet gravity. Galileons are null energy condition violating theories which lead to violations of the second law of thermodynamics of black holes. These higher derivative scalar field theories which are non-minimally coupled to gravity required the development of a generalized method for obtaining the equations of motion. Utilizing this generalized method, it is shown that the inclusion of the Gauss-Bonnet term made the theory of gravity to become higher derivative, which makes it difficult to make any statements about the connection between the violation of the second law of thermodynamics and the galileon fields.
NASA Astrophysics Data System (ADS)
Charmousis, C.; Goutéraux, B.; Kiritsis, E.
2012-09-01
We consider a general Kaluza-Klein reduction of a truncated Lovelock theory. We find necessary geometric conditions for the reduction to be consistent. The resulting lower-dimensional theory is a higher derivative scalar-tensor theory, depends on a single real parameter and yields second-order field equations. Due to the presence of higher-derivative terms, the theory has multiple applications in modifications of Einstein gravity (Galileon/Horndesky theory) and holography (Einstein-Maxwell-Dilaton theories). We find and analyze charged black hole solutions with planar or curved horizons, both in the `Einstein' and `Galileon' frame, with or without cosmological constant. Naked singularities are dressed by a geometric event horizon originating from the higher-derivative terms. The near-horizon region of the near-extremal black hole is unaffected by the presence of the higher derivatives, whether scale invariant or hyperscaling violating. In the latter case, the area law for the entanglement entropy is violated logarithmically, as expected in the presence of a Fermi surface. For negative cosmological constant and planar horizons, thermodynamics and first-order hydrodynamics are derived: the shear viscosity to entropy density ratio does not depend on temperature, as expected from the higher-dimensional scale invariance.
Microstates of the D1-D5-Kaluza-Klein monopole system
Bena, Iosif; Kraus, Per
2005-07-15
We find supergravity solutions corresponding to all U(1)xU(1) invariant chiral primaries of the D1-D5-KK system. These solutions are 1/8 BPS, carry angular momentum, and are asymptotically flat in the 3+1 dimensional sense. They can be thought of as representing the ground states of the four-dimensional black hole constructed from the D1-D5-KK-P system. Demanding the absence of unphysical singularities in our solutions determines all free parameters, and gives precise agreement with the quantum numbers expected from the CFT point of view. The physical mechanism behind the smoothness of the solutions is that the D1 branes and D5 branes expand into a KK-monopole supertube in the transverse space of the original KK monopole.
In this NASA Now episode, Dr. Daniel Patnaude talks about how his team discovered a baby black hole, why this is important and how black holes create tidal forces. Throughout his discussion, Patnau...
NASA Astrophysics Data System (ADS)
Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke
2009-07-01
Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.
NASA Astrophysics Data System (ADS)
Israel, Werner
This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.
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Chiarelli, G; Chirikov-Zorin, I; Chlachidze, G; Chlebana, F; Christofek, L; Chu, M L; Chung, J Y; Chung, W-H; Chung, Y S; Ciobanu, C I; Clark, A G; Coca, M; Connolly, A; Convery, M; Conway, J; Cordelli, M; Cranshaw, J; Culbertson, R; Dagenhart, D; D'Auria, S; De Cecco, S; DeJongh, F; Dell'Agnello, S; Dell'Orso, M; Demers, S; Demortier, L; Deninno, M; De Pedis, D; Derwent, P F; Devlin, T; Dionisi, C; Dittmann, J R; Dominguez, A; Donati, S; D'Onofrio, M; Dorigo, T; Eddy, N; Einsweiler, K; Engels, E; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fan, Q; Farrington, S; Feild, R G; Fernandez, J P; Ferretti, C; Field, R D; Fiori, I; Flaugher, B; Flores-Castillo, L R; Foster, G W; Franklin, M; Freeman, J; Friedman, J; Fukui, Y; Furic, I; Galeotti, S; Gallas, A; Gallinaro, M; Gao, T; Garcia-Sciveres, M; Garfinkel, A F; Gatti, P; Gay, C; Gerdes, D W; Gerstein, E; Giagu, S; Giannetti, P; Giolo, K; Giordani, M; Giromini, P; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Goncharov, M; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Green, C; Gresele, A; Grim, G; Grosso-Pilcher, C; Guenther, M; Guillian, G; Guimaraes da Costa, J; Haas, R M; Haber, C; Hahn, S R; Halkiadakis, E; Hall, C; Handa, T; Handler, R; Happacher, F; Hara, K; Hardman, A D; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Heinrich, J; Heiss, A; Hennecke, M; Herndon, M; Hill, C; Hocker, A; Hoffman, K D; Hollebeek, R; Holloway, L; Hou, S; Huffman, B T; Hughes, R; Huston, J; Huth, J; Ikeda, H; Issever, C; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iwai, J; Iwata, Y; Iyutin, B; James, E; Jones, M; Joshi, U; Kambara, H; Kamon, T; Kaneko, T; Kang, J; Karagoz Unel, M; Karr, K; Kartal, S; Kasha, H; Kato, Y; Keaffaber, T A; Kelley, K; Kelly, M; Kennedy, R D; Kephart, R; Khazins, D; Kikuchi, T; Kilminster, B; Kim, B J; Kim, D H; Kim, H S; Kim, M J; Kim, S B; Kim, S H; Kim, T H; Kim, Y K; Kirby, M; Kirk, M; Kirsch, L; Klimenko, S; Koehn, P; Kondo, K; Konigsberg, J; Korn, A; Korytov, A; Kotelnikov, K; Kovacs, E; Kroll, J; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kurino, K; Kuwabara, T; Kuznetsova, N; Laasanen, A T; Lai, N; Lami, S; Lammel, S; Lancaster, J; Lannon, K; Lancaster, M; Lander, R; Lath, A; Latino, G; LeCompte, T; Le, Y; Lee, J; Lee, S W; Leonardo, N; Leone, S; Lewis, J D; Li, K; Lin, C S; Lindgren, M; Liss, T M; Liu, J B; Liu, T; Liu, Y C; Litvintsev, D O; Lobban, O; Lockyer, N S; Loginov, A; Loken, J; Loreti, M; Lucchesi, D; Lukens, P; Lusin, S; Lyons, L; Lys, J; Madrak, R; Maeshima, K; Maksimovic, P; Malferrari, L; Mangano, M; Manca, G; Mariotti, M; Martignon, G; Martin, M; Martin, A; Martin, V; Martínez, M; Matthews, J A J; Mazzanti, P; McFarland, K S; McIntyre, P; Menguzzato, M; Menzione, A; Merkel, P; Mesropian, C; Meyer, A; Miao, T; Miller, R; Miller, J S; Minato, H; Miscetti, S; Mishina, M; Mitselmakher, G; Miyazaki, Y; Moggi, N; Moore, E; Moore, R; Morita, Y; Moulik, T; Mulhearn, M; Mukherjee, A; Muller, T; Munar, A; Murat, P; Murgia, S; Nachtman, J; Nagaslaev, V; Nahn, S; Nakada, H; Nakano, I; Napora, R; Niell, F; Nelson, C; Nelson, T; Neu, C; Neubauer, M S; Neuberger, D; Newman-Holmes, C; Ngan, C-Y P; Nigmanov, T; Niu, H; Nodulman, L; Nomerotski, A; Oh, S H; Oh, Y D; Ohmoto, T; Ohsugi, T; Oishi, R; Okusawa, T; Olsen, J; Orejudos, W; Pagliarone, C; Palmonari, F; Paoletti, R; Papadimitriou, V; Partos, D; Patrick, J; Pauletta, G; Paulini, M; Pauly, T; Paus, C; Pellett, D; Penzo, A; Pescara, L; Phillips, T J; Piacentino, G; Piedra, J; Pitts, K T; Pompos, A; Pondrom, L; Pope, G; Pratt, T; Prokoshin, F; Proudfoot, J; Ptohos, F; Pukhov, O; Punzi, G; Rademacker, J; Rakitine, A; Ratnikov, F; Ray, H; Reher, D; Reichold, A; Renton, P; Rescigno, M; Ribon, A; Riegler, W; Rimondi, F; Ristori, L; Riveline, M; Robertson, W J; Rodrigo, T; Rolli, S; Rosenson, L; Roser, R; Rossin, R; Rott, C; Roy, A; Ruiz, A; Ryan, D; Safonov, A; St Denis, R; Sakumoto, W K; Saltzberg, D; Sanchez, C; Sansoni, A; Santi, L; Sarkar, S; Sato, H; Savard, P; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Scodellaro, L; Scott, A; Scribano, A; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Shah, T; Shapiro, M D; Shepard, P F; Shibayama, T; Shimojima, M; Shochet, M; Sidoti, A; Siegrist, J; Sill, A; Sinervo, P; Singh, P; Slaughter, A J; Sliwa, K; Snider, F D; Snihur, R; Solodsky, A; Speer, T; Spezziga, M; Sphicas, P; Spinella, F; Spiropulu, M; Spiegel, L; Steele, J; Stefanini, A; Strologas, J; Strumia, F; Stuart, D; Sukhanov, A; Sumorok, K; Suzuki, T; Takano, T; Takashima, R; Takikawa, K; Tamburello, P; Tanaka, M; Tannenbaum, B; Tecchio, M; Tesarek, R J; Teng, P K; Terashi, K; Tether, S; Thom, J; Thompson, A S; Thomson, E; Thurman-Keup, R; Tipton, P; Tkaczyk, S; Toback, D; Tollefson, K; Tonelli, D; Tonnesmann, M; Toyoda, H; Trischuk, W; de Troconiz, J F; Tseng, J; Tsybychev, D; Turini, N; Ukegawa, F; Unverhau, T; Vaiciulis, T; Varganov, A; Vataga, E; Vejcik, S; Velev, G; Veramendi, G; Vidal, R; Vila, I; Vilar, R; Volobouev, I; von der Mey, M; Vucinic, D; Wagner, R G; Wagner, R L; Wagner, W; Wan, Z; Wang, C; Wang, M J; Wang, S M; Ward, B; Waschke, S; Watanabe, T; Waters, D; Watts, T; Weber, M; Wenzel, H; Wester, W C; Whitehouse, B; Wicklund, A B; Wicklund, E; Wilkes, T; Williams, H H; Wilson, P; Winer, B L; Winn, D; Wolbers, S; Wolinski, D; Wolinski, J; Wolinski, S; Wolter, M; Worm, S; Wu, X; Würthwein, F; Wyss, J; Yang, U K; Yao, W; Yeh, G P; Yeh, P; Yi, K; Yoh, J; Yosef, C; Yoshida, T; Yu, I; Yu, S; Yu, Z; Yun, J C; Zanello, L; Zanetti, A; Zetti, F; Zucchelli, S
2004-03-26
We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb(-1) of ppmacr; collisions at sqrt[s]=1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a (3+1+n)-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for n=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.
NASA Astrophysics Data System (ADS)
Levin, Janna; D'Orazio, Daniel
2016-03-01
Black holes are dark dead stars. Neutron stars are giant magnets. As the neutron star orbits the black hole, an electronic circuit forms that generates a blast of power just before the black hole absorbs the neutron star whole. The black hole battery conceivably would be observable at cosmological distances. Possible channels for luminosity include synchro-curvature radiation, a blazing fireball, or even an unstable, short-lived black hole pulsar. As suggested by Mingarelli, Levin, and Lazio, some fraction of the battery power could also be reprocessed into coherent radio emission to populate a subclass of fast radio bursts.
NASA Astrophysics Data System (ADS)
Gilmore, James Brian
2010-12-01
General Relativity is the standard framework by which all gravitational systems are analyzed in modern research, and it provides the theme for all the investigations in this thesis. Beyond this common platform, very different gravitating problems are examined here, and several analytical approaches are used to investigate these systems. Effective field theory, a methodological approach prominent in quantum field theory, plays an important role in the analysis of two of the problems in this thesis. In the first instance, an effective field theory for bound gravitational states is used to compute the interaction Lagrangian of a binary system at the second post-Newtonian order. A metric parametrization based on a temporal Kaluza-Klein decomposition is also used. In this effective field theory calculation, the post-Newtonian results for the equations of motion are elegantly reproduced. In the next problem considered, effective field theory is used to investigate the thermodynamics of compactified charged black holes. The relevant thermodynamic quantities are all computed to second order in the perturbation parameter and finite size effects are incorporated through higher order worldline operators. Complete agreement is found with an exact extremal black hole solution constructed with traditional General Relativistic methods. The results indicate that the addition of charge to a compactified black hole may delay the phase transition to a black string. Finally, the third problem examined here concerns the evolution of perturbations at the end of early universe inflation. General Relativity enters this problem through cosmological perturbation theory. It is shown that the coherent oscillations in the inflaton break down at the comoving post-inflationary horizon size, about 14 e-folds after the end of inflation. This is many e-folds before any known constraints, leading to possible implications for the matching problem of inflation, and the generation of stochastic
BOOK REVIEW: Black Holes, Cosmology and Extra Dimensions Black Holes, Cosmology and Extra Dimensions
NASA Astrophysics Data System (ADS)
Frolov, Valeri P.
2013-10-01
flatness of the Universe, the horizon problem and isotropy of cosmological microwave background. All this material is covered in chapter seven. Chapter eight contains brief discussion of several popular inflation models. Chapter nine is devoted to the problem of the large-scale structure formation from initial quantum vacuum fluctuation during the inflation and the spectrum of the density fluctuations. It also contains remarks on the baryonic asymmetry of the Universe, baryogenesis and primordial black holes. Part III covers the material on extra dimensions. It describes how Einstein gravity is modified in the presence of one or more additional spatial dimensions and how these extra dimensions are compactified in the Kaluza-Klein scheme. The authors also discuss how extra dimensions may affect low energy physics. They present examples of higher-dimensional generalizations of the gravity with higher-in-curvature corrections and discuss a possible mechanism of self-stabilization of an extra space. A considerable part of the chapter 10 is devoted to cosmological models with extra dimensions. In particular, the authors discuss how extra dimensions can modify 'standard' inflation models. At the end of this chapter they make several remarks on a possible relation of the value of fundamental constants in our universe with the existence of extra dimensions. Finally, in chapter 11 they demonstrate that several observable properties of the Universe are closely related with the special value of the fundamental physical constants and their fine tuning. They give interesting examples of such fine tuning and summarize many other cases. The book ends with discussion of a so-called 'cascade birth of universes in multidimensional spaces' model, proposed by one of the authors. As is evident from this brief summary of topics presented in the book, many interesting areas of modern gravity and cosmology are covered. However, since the subject is so wide, this inevitably implies that the
NASA Astrophysics Data System (ADS)
Novikov, Igor
Astrophysics of Black Holes Introduction The Origin of Stellar Black Holes A Nonrotating Black Hole Introduction Schwarzschild Gravitational Field Motion of Photons Along the Radial Direction Radial Motion of Nonrelativistic Particles The Puzzle of the Gravitational Radius R and T Regions Two Types of T-Regions Gravitational Collapse and White Holes Eternal Black Hole? Black Hole Celestial Mechanics Circular Motion Around a Black Hole Gravitational Capture of Particles by a Black Hole Corrections for Gravitational Radiation A Rotating Black Hole Introduction Gravitational Field of a Rotating Black Hole Specific Reference Frames General Properties of the Spacetime of a Rotating Black Hole; - Spacetime Inside the Horizon Celestial Mechanics of a Rotating Black Hole Motion of Particle in the Equatorial Plane Motion of Particles off the Equatorial Plane Peculiarities of the Gravitational Capture of Bodies by a Rotating - Black Hole Electromagnetic Fields Near a Black Hole Introduction Maxwell's Equations in the Neighborhood of a Rotating Black Hole Stationary Electrodynamics Boundary Conditions at the Event Horizon Electromagnetic Fields in Vacuum Magnetosphere of a Black Hole Some Aspects of Physics of Black Holes, Wormholes, and Time Machines Observational Appearence of the Black Holes in the Universe Black Holes in the Interstellar Medium Disk Accretion Black Holes in Stellar Binary Systems Black Holes in Galactic Centers Dynamical Evidence for Black Holes in Galaxy Nuclei Primordial Black Holes Acknowledgements References
NASA Astrophysics Data System (ADS)
Kubota, Hirohisa; Nojiri, Mihoko
2013-04-01
In this paper we study the Higgs(h)-radion(r) system of the Randall-Sundum model where matter fermions and gauge fields live in the bulk while the Higgs boson resides on the infrared brane. We take into account the Kaluza-Klein loop correction to the hVV and rVV couplings where V=g, γ. Inspired by the LHC data in 2011 in which a hint of the Higgs boson has been seen at 125 GeV, we fix one of the mass eigenstates of the Higgs-radion mixed state at 125 GeV and scan over all the other parameters that have not been excluded by the 2011 Higgs search data. We find the regions of parameter space where the scalar particle at 125 GeV has a signal rate significantly larger or smaller than that of the Standard Model (SM) Higgs boson. The signal ratio Br(ZZ)/Br(γγ) also may deviate from that of the SM Higgs boson.
Matsumoto, Shigeki; Sato, Joe; Yamanaka, Masato; Senami, Masato
2009-09-01
We calculate the production rates of the second Kaluza-Klein (KK) photon {gamma}{sup (2)} and Z boson Z{sup (2)} at the LHC including all significant processes in the minimal universal extra dimension (MUED) model. For discrimination of the MUED model from other TeV scale models at the LHC, {gamma}{sup (2)} and Z{sup (2)} play a crucial role. In order to discuss the discrimination and calculate their production rates, we derive KK number violating operators including the contribution of the top Yukawa coupling. Using these operators, we accurately calculate branching ratios of second KK particles. In addition we find that these KK number violating operators provide new processes for {gamma}{sup (2)} and Z{sup (2)} productions, such as cascade decay from second KK quarks produced through these operators. They have large contributions to their total production rates. In particular, these production processes give the dominant contribution for {gamma}{sup (2)} production for 1/R > or approx. 800 GeV. As a result, with an integrated luminosity of 100 fb{sup -1}, the number of produced {gamma}{sup (2)} and Z{sup (2)} are estimated as 10{sup 6}-10{sup 2} for the compactification scale between 400 and 2000 GeV.
NASA Astrophysics Data System (ADS)
Dienes, Keith R.; Kost, Jeff; Thomas, Brooks
2017-06-01
We study the early-universe cosmology of a Kaluza-Klein (KK) tower of scalar fields in the presence of a mass-generating phase transition, focusing on the time development of the total tower energy density (or relic abundance) as well as its distribution across the different KK modes. We find that both of these features are extremely sensitive to the details of the phase transition and can behave in a variety of ways significant for late-time cosmology. In particular, we find that the interplay between the temporal properties of the phase transition and the mixing it generates are responsible for both enhancements and suppressions in the late-time abundances, sometimes by many orders of magnitude. We map out the complete model parameter space and determine where traditional analytical approximations are valid and where they fail. In the latter cases we also provide new analytical approximations which successfully model our results. Finally, we apply this machinery to the example of an axion-like field in the bulk, mapping these phenomena over an enlarged axion parameter space that extends beyond that accessible to standard treatments. An important by-product of our analysis is the development of an alternate "UV-based" effective truncation of KK theories which has a number of interesting theoretical properties that distinguish it from the more traditional "IR-based" truncation typically used in the extra-dimension literature.
Uniformly accelerated black holes
NASA Astrophysics Data System (ADS)
Letelier, Patricio S.; Oliveira, Samuel R.
2001-09-01
The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.
NASA Astrophysics Data System (ADS)
Chung, Hyeyoun
2015-10-01
This thesis explores the evolution of different types of black holes, and the ways in which black hole dynamics can be used to answer questions about other physical systems. We first investigate the differences in observable gravitational effects between a four-dimensional Randall-Sundrum (RS) braneworld universe compared to a universe without the extra dimension, by considering a black hole solution to the braneworld model that is localized on the brane. When the brane has a negative cosmological constant, then for a certain range of parameters for the black hole, the intersection of the black hole with the brane approximates a Banados-Teitelboim-Zanelli (BTZ) black hole on the brane with corrections that fall off exponentially outside the horizon. We compute the quasinormal modes of the braneworld black hole, and compare them to the known quasinormal modes of the three-dimensional BTZ black hole. We find that there are two distinct regions for the braneworld black hole solutions that are reflected in the dependence of the quasinormal modes on the black hole mass. The imaginary parts of the quasinormal modes display phenomenological similarities to the quasinormal modes of the three-dimensional BTZ black hole, indicating that nonlinear gravitational effects may not be enough to distinguish between a lower-dimensional theory and a theory derived from a higher-dimensional braneworld. Secondly, we consider the evolution of non-extremal black holes in N=4, d=2 supergravity, and investigate how such black holes might evolve over time if perturbed away from extremality. We study this problem in the probe limit by finding tunneling amplitudes for a Dirac field in a single-centered background, which gives the decay rates for the emission of charged probe black holes from the central black hole. We find that there is no minimum to the potential for the probe particles at a finite distance from the central black hole, so any probes that are emitted escape to infinity. If
NASA Astrophysics Data System (ADS)
Loeb, Abraham
2007-04-01
Recent data indicates that almost all galaxies possess a supermassive black hole at their center. When gas accretes onto the black hole it heats-up and shines, resulting in the appearance of a bright quasar. The earliest quasars are found to exist only a billion years after the big-bang. I will describe recent observations of both the nearest and the most distant supermassive black holes in the universe. The formation and evolution of the black hole population can be described in the context of popular models for galaxy formation. I will describe the key questions that drive current research on supermassive black holes and present theoretical work on the radiative and hydrodynamic effects that quasars have on their cosmic habitat. Within the coming decade it would be possible to test general relativity by monitoring over time, and possibly even imaging, the polarized emission from hot spots around the black hole in the center of our Galaxy (SgrA*).
NASA Technical Reports Server (NTRS)
Oliversen, Ronald J. (Technical Monitor); Garcia, M.
2003-01-01
The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies. This program facilitates this study by funding related travel, computer equipment, and partial salary for a post-doc.
NASA Technical Reports Server (NTRS)
Garcia, M.; Oliversen, Ronald J. (Technical Monitor)
2004-01-01
The goal of this program is to study black holes, both in our Galaxy and in nearby galaxies. We aim to study both 'stellar mass' x-ray binaries containing black holes (both in our Galaxy and in nearby galaxies), and super-massive black holes in nearby galaxies. This program facilitate this study by funding related travel, computer equipment, and partial salary for a post-doc.
NASA Astrophysics Data System (ADS)
Ho, Pei-Ming
2017-04-01
Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.
Begelman, Mitchell C
2003-06-20
Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity.
A black hole quartet: New solutions and applications to string theory
NASA Astrophysics Data System (ADS)
Padi, Megha
In this thesis, we study a zoo of black hole solutions which help us connect string theory to the universe we live in. The intuition for how to attack fundamental problems can often be found in a toy model. In Chapter 2, we show that three-dimensional topologically massive gravity with a negative cosmological constant -ℓ -2 and coupling constant has "warped AdS3" solutions with SL(2, R ) x U(1) isometry. For muℓ > 3, we show that certain discrete quotients of warped AdS3 lead to black holes. Their thermodynamics is consistent with the existence of a holographic dual CFT with central charges cR = 15mℓ 2+81Gmm ℓ2+27 and cL = 12mℓ 2Gmm ℓ2+27 . The entropy of many supersymmetric black holes have been accounted for, but more realistic non-supersymmetric black holes have been largely overlooked. In Chapter 3, we derive new single-centered and multi-centered non-BPS black hole solutions for several four dimensional models which, after Kaluza-Klein reduction, admit a description in terms of a sigma model with symmetric target space. In particular, we provide the exact solution with generic charges and asymptotic moduli in N=2 supergravity coupled to one vector multiplet. As it stands, the current formulation of string theory allows for an extremely large number of possible solutions (or vacua). We first analyze this landscape by looking for universal characteristics. In Chapter 4, we provide evidence for the conjecture that gravity is always the weakest force in any string compactification. We show that, in several examples arising in string theory, higher-derivative corrections always make extremal non-supersymmetric black holes lighter than the classical bound M/Q = 1. In Chapter 5, we construct novel black hole bound states, called orientiholes, that are T-dual to IIB orientifold compactifications. The gravitational entropy of such orientiholes provides an "experimental" estimate of the number of vacua in various sectors of the IIB landscape. Furthermore
Kleihaus, B; Kunz, J
2001-04-23
We construct stationary black-hole solutions in SU(2) Einstein-Yang-Mills theory which carry angular momentum and electric charge. Possessing nontrivial non-Abelian magnetic fields outside their regular event horizon, they represent nonperturbative rotating hairy black holes.
NASA Astrophysics Data System (ADS)
Reynolds, Christopher S.
2015-08-01
Black hole spin is important in both the fundamental physics and astrophysics realms. In fundamental terms, many extensions and alternatives to General Relativity (GR) reveal themselves through effects related to (or at least of the same order as) spin. Astrophysically, spin is a fossil record of how black holes have grown and may, in addition, be an important source of energy (e.g., powering relativistic jets from black hole systems). I shall review recent progress on observational studies of black hole spin, especially those made in the X-ray waveband. We now have multiple techniques that can be applied in our search for black hole spin; I shall discuss the concordance (or, sometimes, lack thereof) between these techniques. Finally, I shall discuss what we can expect in the next few years with the launch of new X-ray instrumentation as well as the deployment of the Event Horizon Telescope.
Fluctuating black hole horizons
NASA Astrophysics Data System (ADS)
Mei, Jianwei
2013-10-01
In this paper we treat the black hole horizon as a physical boundary to the spacetime and study its dynamics following from the Gibbons-Hawking-York boundary term. Using the Kerr black hole as an example we derive an effective action that describes, in the large wave number limit, a massless Klein-Gordon field living on the average location of the boundary. Complete solutions can be found in the small rotation limit of the black hole. The formulation suggests that the boundary can be treated in the same way as any other matter contributions. In particular, the angular momentum of the boundary matches exactly with that of the black hole, suggesting an interesting possibility that all charges (including the entropy) of the black hole are carried by the boundary. Using this as input, we derive predictions on the Planck scale properties of the boundary.
Dumb holes: analogues for black holes.
Unruh, W G
2008-08-28
The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.
NASA Astrophysics Data System (ADS)
Hartman, Thomas Edward
The connection between black holes in four dimensions and conformal field theories (CFTs) in two dimensions is explored, focusing on zero temperature (extreme) black holes and their low-temperature cousins. It is shown that extreme black holes in a theory of quantum gravity are holographically dual to field theories living in two dimensions without gravity, and that the field theory reproduces a variety of black hole phenomena in detail. The extreme black hole/CFT correspondence is derived from a symmetry analysis near the horizon of a Kerr black hole with mass M and maximal angular momentum J=M 2. The asymptotic symmetry generators form one copy of the Virasoro algebra with central charge c=12J, which implies that the near-horizon quantum states are identical to those of a two-dimensional CFT. We discuss extensions of this result to near-extreme black holes and cosmological horizons. Astrophysical black holes are never exactly extremal, but the black hole GRS1915+105 observed through X-ray and radio telescopy is likely within 1% of the extremal spin, suggesting that this extraordinary and well studied object is approximately dual to a two-dimensional CFT with c˜1079. As evidence for the correspondence, microstate counting in the CFT is used to derive the Bekenstein-Hawking area law for the Kerr entropy, S=Horizon area/4. Furthermore, the correlators in the dual CFT are shown to reproduce the scattering amplitudes of a charged scalar or spin-½ field by a near-extreme Kerr-Newman black hole, and a neutral spin-1 or spin-2 field by a near-extreme Kerr black hole. Scattering amplitudes probe the vacuum of fields living on the black hole background. For scalars, bound superradiant modes lead to an instability, while for fermions, it is shown that the bound superradiant modes condense and form a Fermi sea which extends well outside the ergosphere. Assuming no further instabilities, the low energy effective theory near the black hole is described by ripples in the
Gauge/Gravity correspondence and black hole attractors in various dimensions
NASA Astrophysics Data System (ADS)
Li, Wei
This thesis investigates several topics on Gauge/Gravity correspondence and black hole attractors in various dimensions. The first chapter contains a brief review and summary of main results. Chapters 2 and 3 aim at a microscopic description of black objects in five dimensions. Chapter 2 studies higher-derivative corrections for 5D black rings and spinning black holes. It shows that certain R 2 terms found in Calabi-Yau compactifications of M-theory yield macroscopic corrections to the entropies that match the microscopic corrections. Chapter 3 constructs probe brane configurations that preserve half of the enhanced near-horizon supersymmetry of 5D spinning black holes, whose near-horizon geometry is squashed AdS2 x S 3. There are supersymmetric zero-brane probes stabilized by orbital angular momentum on S3 and one-brane probes with momentum and winding around a U(1)L x U(1)R torus in S3. Chapter 4 constructs and analyzes generic single-centered and multi-centered black hole attractor solutions in various four-dimensional models which, after Kaluza-Klein reduction, admit a description in terms of 3D gravity coupled to a sigma model whose target space is symmetric coset space. The solutions correspond to certain nilpotent generators of the coset algebra. The non-BPS black hole attractors are found to be drastically different from their BPS counterparts. Chapter 5 examines three-dimensional topologically massive gravity with negative cosmological constant in asymptotically AdS 3 spacetimes. It proves that the theory is unitary and stable only at a special value of Chern-Simons coupling, where the theory becomes chiral. This suggests the existence of a stable, consistent quantum gravity theory at the chiral point which is dual to a holomorphic boundary CFT 2. Finally, Chapter 6 studies the two-dimensional N = 1 critical string theory with a linear dilaton background. It constructs time-dependent boundary state solutions that correspond to D0-branes falling toward the
NASA Technical Reports Server (NTRS)
1999-01-01
This graphic shows the computer simulation of a black hole from start to finish. Plasma is falling slowly toward the black hole in a (at the upper left). The plasma has a magnetic field, shown by the white lines. It picks up speed as it falls toward the hole in b (at the upper right), c (lower left) and d (lower right). However, the rotating black hole twists up space itself (and the magnetic field lines) and ejects electromagnetic power along the north and south poles above the black hole. The red and white color shows the immense electromagnetic power output, which eventually will pick up particles and form squirting jets. This simulation was conducted using supercomputers at Japan's National Institute for Fusion Science.
1999-11-30
This graphic shows the computer simulation of a black hole from start to finish. Plasma is falling slowly toward the black hole in a (at the upper left). The plasma has a magnetic field, shown by the white lines. It picks up speed as it falls toward the hole in b (at the upper right), c (lower left) and d (lower right). However, the rotating black hole twists up space itself (and the magnetic field lines) and ejects electromagnetic power along the north and south poles above the black hole. The red and white color shows the immense electromagnetic power output, which eventually will pick up particles and form squirting jets. This simulation was conducted using supercomputers at Japan's National Institute for Fusion Science. http://photojournal.jpl.nasa.gov/catalog/PIA04206
ULTRAMASSIVE BLACK HOLE COALESCENCE
Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter E-mail: k.holley@vanderbilt.edu
2015-01-10
Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production.
Mathur, Samir D.
2012-11-15
The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: Black-Right-Pointing-Pointer The information paradox is a serious problem. Black-Right-Pointing-Pointer To solve it we need to find 'hair' on black holes. Black-Right-Pointing-Pointer In string theory we find 'hair' by the fuzzball construction. Black-Right-Pointing-Pointer Fuzzballs help to resolve many other issues in gravity.
NASA Astrophysics Data System (ADS)
Garmire, Gordon
1999-09-01
WE PROPOSE TO CARRY OUT A SYSTEMATIC STUDY OF EMISSION AND ABSORPTION SPECTRAL FEATURES THAT ARE OFTEN SEEN IN X-RAY SPECTRA OF BLACK HOLE BINARIES. THE EXCELLENT SENSITIVITY AND ENERGY RESOLUTION OF THE ACIS/HETG COMBINATION WILL NOT ONLY HELP RESOLVE AMBIGUITIES IN INTERPRETING THESE FEATURES, BUT MAY ALLOW MODELLING OF THE EMISSION LINE PROFILES IN DETAIL. THE PROFILES MAY CONTAIN INFORMATION ON SUCH FUNDAMENTAL PROPERTIES AS THE SPIN OF BLACK HOLES. THEREFORE, THIS STUDY COULD LEAD TO A MEASUREMENT OF BLACK HOLE SPIN FOR SELECTED SOURCES. THE RESULT CAN THEN BE DIRECTLY COMPARED WITH THOSE FROM PREVIOUS STUDIES BASED ON INDEPENDENT METHODS.
ERIC Educational Resources Information Center
Ruffini, Remo; Wheeler, John A.
1971-01-01
discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)
NASA Astrophysics Data System (ADS)
Barr, Ian A.; Bull, Anne; O'Brien, Eileen; Drillsma-Milgrom, Katy A.; Milgrom, Lionel R.
2016-07-01
Two-dimensional shadows formed by illuminating vortices are shown to be visually analogous to the gravitational action of black holes on light and surrounding matter. They could be useful teaching aids demonstrating some of the consequences of general relativity.
ERIC Educational Resources Information Center
Ruffini, Remo; Wheeler, John A.
1971-01-01
discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)
2016-07-28
The blue dots in this field of galaxies, known as the COSMOS field, show galaxies that contain supermassive black holes emitting high-energy X-rays. The black holes were detected by NASA's Nuclear Spectroscopic Array, or NuSTAR, which spotted 32 such black holes in this field and has observed hundreds across the whole sky so far. The other colored dots are galaxies that host black holes emitting lower-energy X-rays, and were spotted by NASA's Chandra X-ray Observatory. Chandra data show X-rays with energies between 0.5 to 7 kiloelectron volts, while NuSTAR data show X-rays between 8 to 24 kiloelectron volts. http://photojournal.jpl.nasa.gov/catalog/PIA20865
2007-10-25
NASA Spitzer and Chandra space telescopes have uncovered a long-lost population of active supermassive black holes, or quasars located deep in the bellies of distant, massive galaxies circled in blue.
2013-11-26
The magenta spots in this image from NASA NuSTAR show two black holes in the spiral galaxy called NGC 1313, or the Topsy Turvy galaxy, located about 13 million light-years away in the Reticulum constellation.
Black hole geometrothermodynamics
NASA Astrophysics Data System (ADS)
Quevedo, Hernando
2017-03-01
We review the main aspects of geometrothermodynamics which is a geometric formalism to describe thermodynamic systems, taking into account the invariance of classical thermodynamics with respect to Legendre transformations. We focus on the particular case of black holes, and present a Riemannian metric which describes the corresponding space of equilibrium states. We show that this metric can be used to describe the stability properties and phase transition structure of black holes in different gravity theories.
NASA Technical Reports Server (NTRS)
Garcia, M.
1998-01-01
Our UV/VIS work concentrates on black hole X-ray nova. These objects consist of two stars in close orbit, one of which we believe is a black hole - our goal is to SHOW that one is a black hole. In order to reach this goal we carry out observations in the Optical, UV, IR and X-ray bands, and compare the observations to theoretical models. In the past year, our UV/VIS grant has provided partial support (mainly travel funds and page charges) for work we have done on X-ray nova containing black holes and neutron stars. We have been very successful in obtaining telescope time to support our project - we have completed approximately a dozen separate observing runs averaging 3 days each, using the MMT (5M), Lick 3M, KPNO 2.1M, CTIO 4M, CTIO 1.5M, and the SAO/WO 1.2M telescopes. These observations have allowed the identification of one new black hole (Nova Oph 1977), and allowed the mass of another to be measured (GS2000+25). Perhaps our most exciting new result is the evidence we have gathered for the existence of 'event horizons' in black hole X-ray nova.
Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar E-mail: christos.charmousis@th.u-psud.fr
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.
NASA Astrophysics Data System (ADS)
Lukman, Dragan; Borštnik, Norma Susana Mankoč
2017-04-01
It is shown that in the spin-charge-family theory (Mankoč Borštnik in arXiv:1607.01618v2 Phys Rev D 91:065004 (2016). 1409.7791, Mod Phys 6:2244 (205). 10.4236/jmp.2015.615230 (2015). arxiv.org/abs/1409.4981 (2016), J Mod Phys 4:823. 10.4236/jmp.2013.46113. arxiv:1312.1542 (2013) arxiv:1409.4981 (2014), as well as in all the Kaluza-Klein like theories (Blagojević in Gravitation and gauge symmetries, IoP Publishing, Bristol, 2002, An introduction to Kaluza-Klein theories, World Scientific, Singapore, 1983), vielbeins and spin connections manifest in d=(3+1) space equivalent vector gauge fields, when space with d\\ge 5 has a large enough symmetry. The authors demonstrate this equivalence in spaces with the symmetry of the metric tensor in the space out of d=(3+1)-g^{σ τ } = η ^{σ τ } f2 - for any scalar function f of the coordinates x^{σ }, where x^{σ } denotes the coordinates of space out of d=(3+1). Also the connection between vielbeins and scalar gauge fields in d=(3+1) (offering the explanation for the Higgs scalar) is discussed.
ERIC Educational Resources Information Center
Science Teacher, 2005
2005-01-01
Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…
ERIC Educational Resources Information Center
Science Teacher, 2005
2005-01-01
Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…
NASA Astrophysics Data System (ADS)
Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.
2011-10-01
In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.
NASA Astrophysics Data System (ADS)
Centrella, Joan
2009-05-01
The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.
NASA Technical Reports Server (NTRS)
Centrella, John
2009-01-01
The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.
1999-11-30
This three-dimensional illustration shows how the rotating space around a black hole twists up the magnetic field in the plasma falling toward the black hole. The black sphere at the center of the figure is the black hole itself. http://photojournal.jpl.nasa.gov/catalog/PIA04207
NASA Astrophysics Data System (ADS)
Furmann, John M.
2003-03-01
Black holes are difficult to study because they emit no light. To overcome this obstacle, scientists are trying to recreate a black hole in the laboratory. The article gives an overview of the theories of Einstein and Hawking as they pertain to the construction of the Large Hadron Collider (LHC) near Geneva, Switzerland, scheduled for completion in 2006. The LHC will create two beams of protons traveling in opposing directions that will collide and create a plethora of scattered elementary particles. Protons traveling in opposite directions at very high velocities may create particles that come close enough to each other to feel their compacted higher dimensions and create a mega force of gravity that can create tiny laboratory-sized black holes for fractions of a second. The experiments carried out with LHC will be used to test modern string theory and relativity.
NASA Technical Reports Server (NTRS)
Centrella, Joan
2012-01-01
The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics
Black hole entropy quantization.
Corichi, Alejandro; Díaz-Polo, Jacobo; Fernández-Borja, Enrique
2007-05-04
Ever since the pioneering works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic invariant. This lead to the suggestion that the black hole area should also be quantized in equidistant steps to account for the discrete black hole entropy. Here we shall show that loop quantum gravity, in which area is not quantized in equidistant steps, can nevertheless be consistent with Bekenstein's equidistant entropy proposal in a subtle way. For that we perform a detailed analysis of the number of microstates compatible with a given area and show consistency with the Bekenstein framework when an oscillatory behavior in the entropy-area relation is properly interpreted.
NASA Technical Reports Server (NTRS)
Centrella, Joan
2010-01-01
The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wove detection, testing general relativity, and astrophysics.
Noncommutative black hole thermodynamics
Banerjee, Rabin; Majhi, Bibhas Ranjan; Samanta, Saurav
2008-06-15
We give a general derivation, for any static spherically symmetric metric, of the relation T{sub h}=(K/2{pi}) connecting the black hole temperature (T{sub h}) with the surface gravity (K), following the tunneling interpretation of Hawking radiation. This derivation is valid even beyond the semi-classical regime, i.e. when quantum effects are not negligible. The formalism is then applied to a spherically symmetric, stationary noncommutative Schwarzschild space-time. The effects of backreaction are also included. For such a black hole the Hawking temperature is computed in a closed form. A graphical analysis reveals interesting features regarding the variation of the Hawking temperature (including corrections due to noncommutativity and backreaction) with the small radius of the black hole. The entropy and tunneling rate valid for the leading order in the noncommutative parameter are calculated. We also show that the noncommutative Bekenstein-Hawking area law has the same functional form as the usual one.
NASA Technical Reports Server (NTRS)
Centrella, Joan
2010-01-01
The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wove detection, testing general relativity, and astrophysics.
NASA Technical Reports Server (NTRS)
Centrella, Joan
2010-01-01
The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.
Yang, Huan; Zimmerman, Aaron; Lehner, Luis
2015-02-27
We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.
NASA Astrophysics Data System (ADS)
Joshi, Pankaj S.; Narayan, Ramesh
2016-10-01
We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals.
Lyutikov, Maxim; McKinney, Jonathan C.
2011-10-15
The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N{sub B}=e{Phi}{sub {infinity}}/({pi}c({h_bar}/2{pi})), where {Phi}{sub {infinity}}{approx_equal}2{pi}{sup 2}B{sub NS}R{sub NS}{sup 3}/(P{sub NS}c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.
NASA Astrophysics Data System (ADS)
Dokuchaev, Vyacheslav
2013-11-01
It is considered the test planet and photon orbits of the third kind inside the black hole (BH), which are stable, periodic and neither come out the BH nor terminate at the central singularity. Interiors of the supermassive BHs may be inhabited by advanced civilizations living on the planets with the third kind orbits. In principle, one can get information from the interiors of BHs by observing their white hole counterparts.
NASA Astrophysics Data System (ADS)
Hennigar, Robie A.; Mann, Robert B.; Tjoa, Erickson
2017-01-01
We present what we believe is the first example of a "λ -line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid 4He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.
NASA Technical Reports Server (NTRS)
Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.
2010-01-01
Black-hole mergers take place in regions of very strong and dynamical gravitational fields, and are among the strongest sources of gravitational radiation. Probing these mergers requires solving the full set of Einstein's equations of general relativity numerically. For more than 40 years, progress towards this goal has been very slow, as numerical relativists encountered a host of difficult problems. Recently, several breakthroughs have led to dramatic progress, enabling stable and accurate calculations of black-hole mergers. This article presents an overview of this field, including impacts on astrophysics and applications in gravitational wave data analysis.
Characterizing Black Hole Mergers
NASA Technical Reports Server (NTRS)
Baker, John; Boggs, William Darian; Kelly, Bernard
2010-01-01
Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.
2017-09-28
When two black holes collide, they release massive amounts of energy in the form of gravitational waves that last a fraction of a second and can be "heard" throughout the universe - if you have the right instruments. Today we learned that the #LIGO project heard the telltale chirp of black holes colliding, fulfilling Einstein's General Theory of Relativity. NASA's LISA mission will look for direct evidence of gravitational waves. go.nasa.gov/23ZbqoE This video illustrates what that collision might look like.
Characterizing Black Hole Mergers
NASA Technical Reports Server (NTRS)
Baker, John; Boggs, William Darian; Kelly, Bernard
2010-01-01
Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.
NASA Technical Reports Server (NTRS)
Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.
2010-01-01
Black-hole mergers take place in regions of very strong and dynamical gravitational fields, and are among the strongest sources of gravitational radiation. Probing these mergers requires solving the full set of Einstein's equations of general relativity numerically. For more than 40 years, progress towards this goal has been very slow, as numerical relativists encountered a host of difficult problems. Recently, several breakthroughs have led to dramatic progress, enabling stable and accurate calculations of black-hole mergers. This article presents an overview of this field, including impacts on astrophysics and applications in gravitational wave data analysis.
Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson
2017-01-13
We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.
NASA Astrophysics Data System (ADS)
Good, Michael R. R.; Ong, Yen Chin
2015-02-01
A (3 +1 )-dimensional asymptotically flat Kerr black hole angular speed Ω+ can be used to define an effective spring constant, k =m Ω+2. Its maximum value is the Schwarzschild surface gravity, k =κ , which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: 2 π T =κ -k . Hooke's law, in the extremal limit, provides the force F =1 /4 , which is consistent with the conjecture of maximum force in general relativity.
NASA Technical Reports Server (NTRS)
Dowker, Fay; Gregory, Ruth; Traschen, Jennie
1991-01-01
We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviors, at the horizon and at infinity, of vortex solutions for the gauge and scalar fields in an abelian Higgs model on a Euclidean Schwarzschild background and interpolate between them by integrating the equations numerically. Calculating the backreaction shows that the effect of the vortex is to cut a slice out of the Schwarzschild geometry. Consequences of these solutions for black hole thermodynamics are discussed.
Nonisolated dynamic black holes and white holes
McClure, M. L.; Anderson, Kaem; Bardahl, Kirk
2008-05-15
Modifying the Kerr-Schild transformation used to generate black and white hole spacetimes, new dynamic black and white holes are obtained using a time-dependent Kerr-Schild scalar field. Physical solutions are found for black holes that shrink with time and for white holes that expand with time. The black hole spacetimes are physical only in the vicinity of the black hole, with the physical region increasing in radius with time. The white hole spacetimes are physical throughout. Unlike the standard Schwarzschild solution the singularities are nonisolated, since the time dependence introduces a mass-energy distribution. The surfaces in the metrics where g{sub tt}=g{sup rr}=0 are dynamic, moving inward with time for the black holes and outward for the white holes, which leads to a question of whether these spacetimes truly have event horizons--a problem shared with Vaidya's cosmological black hole spacetimes. By finding a surface that shrinks or expands at the same rate as the null geodesics move, and within which null geodesics move inward or outward faster than the surfaces shrink or expand, respectively, it is verified that these do in fact behave like black and white holes.
NASA Astrophysics Data System (ADS)
Lyutikov, Maxim; McKinney, Jonathan C.
2011-10-01
The “no-hair” theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively “frozen in” the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes NB=eΦ∞/(πcℏ), where Φ∞≈2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole’s magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.
Flaring Black Hole Artist Concept
2011-09-20
This artist concept illustrates what the flaring black hole called GX 339-4 might look like. Infrared observations from NASA WISE reveal the best information yet on the chaotic and extreme environments of this black hole jets.
Different Flavors of Black Holes
2014-01-09
A range of supermassive black holes lights up this new image from NASA NuSTAR. All of the dots are active black holes tucked inside the hearts of galaxies, with colors representing different energies of X-ray light.
Anabalón, Andrés; Astefanesei, Dumitru
2015-03-26
We review the existence of exact hairy black holes in asymptotically flat, anti-de Sitter and de Sitter space-times. We briefly discuss the issue of stability and the charging of the black holes with a Maxwell field.
Growth of Primordial Black Holes
NASA Astrophysics Data System (ADS)
Harada, Tomohiro
Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.
NASA Astrophysics Data System (ADS)
Bossard, Guillaume
2012-05-01
Using algebraic tools inspired by the study of nilpotent orbits in simple Lie algebras, we obtain a large class of solutions describing interacting non-BPS black holes in {N} = 8 supergravity, which depend on 44 harmonic functions. For this purpose, we consider a truncation {E_{{{6}({6})}}}/S{p_{{c}}}( {8,{R}} ) subset {E_{{{8}({8})}}}/{{Spin}}_{{c}}^{ * }( {16} ) of the non-linear sigma model describing stationary solutions of the theory, which permits a reduction of algebraic computations to the multiplication of 27 by 27 matrices. The lift to {N} = 8 supergravity is then carried out without loss of information by using a pertinent representation of the moduli parametrizing E7(7)/SUc (8) in terms of complex valued Hermitian matrices over the split octonions, which generalise the projective coordinates of exceptional special K¨ahler manifolds. We extract the electromagnetic charges, mass and angular momenta of the solutions, and exhibit the duality invariance of the black holes distance separations. We discuss in particular a new type of interaction which appears when interacting non-BPS black holes are not aligned. Finally we will explain the possible generalisations toward the description of the most general stationary black hole solutions of {N} = 8 supergravity.
NASA Astrophysics Data System (ADS)
Gregory, Ruth; Kubizňák, David; Wills, Danielle
2013-06-01
A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that 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 conical with respect to a local co-rotating frame, not with respect to the static frame at infinity.
NASA Technical Reports Server (NTRS)
Baker, John
2010-01-01
Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.
Nathanail, Antonios; Contopoulos, Ioannis
2014-06-20
We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.
NASA Technical Reports Server (NTRS)
Baker, John
2010-01-01
Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.
Gravitation without black holes
Agnese, A.G.; La Camera, M.
1985-03-15
The Schwarzschild, Reissner-Nordstroem, and Kerr exterior solutions in general relativity are reconsidered adding to the vacuum a massless scalar field. The event horizons in the modified solutions all reduce to a point, thus preventing the formation of black holes.
2015-07-09
This cartoon shows how magnetic waves, called Alfvén S-waves, propagate outward from the base of black hole jets. The jet is a flow of charged particles, called a plasma, which is launched by a black hole. The jet has a helical magnetic field (yellow coil) permeating the plasma. The waves then travel along the jet, in the direction of the plasma flow, but at a velocity determined by both the jet's magnetic properties and the plasma flow speed. The BL Lac jet examined in a new study is several light-years long, and the wave speed is about 98 percent the speed of light. Fast-moving magnetic waves emanating from a distant supermassive black hole undulate like a whip whose handle is being shaken by a giant hand, according to a study using data from the National Radio Astronomy Observatory's Very Long Baseline Array. Scientists used this instrument to explore the galaxy/black hole system known as BL Lacertae (BL Lac) in high resolution. http://photojournal.jpl.nasa.gov/catalog/PIA19822
Towards noncommutative quantum black holes
Lopez-Dominguez, J. C.; Obregon, O.; Sabido, M.; Ramirez, C.
2006-10-15
In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.
Bender, P.; Bloom, E.; Cominsky, L.
1995-07-01
Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.
Weighing supermassive black holes
NASA Astrophysics Data System (ADS)
Rafiee, Alireza
We calculate the black hole masses for a sample of 27728 quasars selected from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3). To ensure a high signal-to-noise ratio, we reconstruct quasar spectra for this large sample of quasars using the eigenspectra method (Yip et al., 2004). This method reduces the uncertainty of the measurements for even noisy original spectra, making almost all the SDSS quasar spectra usable for our study. A few applications for black hole mass estimates are presented here. Wang et al. (2006) estimated an average radiative efficiency of 30%-35% for quasars at moderate redshift, which implies that most supermassive black holes are rotating very rapidly. Using our black hole mass estimates, we have found that their method is not independent of quasar lifetimes and thus that quasars do not necessarily have such high efficiencies. As a second application, we have investigated a claim by Steinhardt and Elvis (2009) that there exists a sub-Eddington boundary in the quasar mass-luminosity plane using the Shen et al. (2008) mass estimates. We re-calibrate the mass-scaling relations following Wang et al. (2009) with the most up-to-date reverberation estimates of black hole masses. We compare results from the original data sets with the new re-calibrated estimates of the mass-luminosity plane. We conclude that the presence of the sub-Eddington boundary in the original data of Shen et al. (2008) is likely due to biases in the mass-scaling relation and not to any physical process.
Black holes on gravitational instantons
NASA Astrophysics Data System (ADS)
Chen, Yu; Teo, Edward
2011-09-01
In this paper, we classify and construct five-dimensional black holes on gravitational instantons in vacuum Einstein gravity, with R×U(1)×U(1) isometry. These black holes have spatial backgrounds which are Ricci-flat gravitational instantons with U(1)×U(1) isometry, and are completely regular space-times outside the event horizon. Most of the known exact five-dimensional vacuum black-hole solutions can be classified within this scheme. Amongst the new space-times presented are static black holes on the Euclidean Kerr and Taub-bolt instantons. We also present a rotating black hole on the Eguchi-Hanson instanton.
NASA Astrophysics Data System (ADS)
Bena, Iosif; El-Showk, Sheer; Vercnocke, Bert
These lectures notes provide a fast-track introduction to modern developments in black hole physics within string theory, including microscopic computations of the black hole entropy as well as construction and quantization of microstates using supergravity. These notes are largely self-contained and should be accessible to students at an early PhD or Masters level. Topics covered include the black holes in supergravity, D-branes, Strominger-Vafa's computation of the black hole entropy via D-branes, AdS-CFT and its applications to black hole phyisics, multicenter solutions, and the geometric quantization of the latter.
NASA Astrophysics Data System (ADS)
Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.
2017-02-01
We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.
Roldán-Molina, A; Nunez, Alvaro S; Duine, R A
2017-02-10
We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.
Prisons of light : black holes
NASA Astrophysics Data System (ADS)
Ferguson, Kitty
What is a black hole? Could we survive a visit to one -- perhaps even venture inside? Have we yet discovered any real black holes? And what do black holes teach us about the mysteries of our Universe? These are just a few of the tantalizing questions examined in this tour-de-force, jargon-free review of one of the most fascinating topics in modern science. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light - Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.
NASA Astrophysics Data System (ADS)
Polchinski, Joseph
2015-04-01
Our modern understanding of space, time, matter, and even reality itself arose from the three great revolutions of the early twentieth century: special relativity, general relativity, and quantum mechanics. But a century later, this work is unfinished. Many deep connections have been discovered, but the full form of a unified theory incorporating all three principles is not known. Thought experiments and paradoxes have often played a key role in figuring out how to fit theories together. For the unification of general relativity and quantum mechanics, black holes have been an important arena. I will talk about the quantum mechanics of black holes, the information paradox, and the latest version of this paradox, the firewall. The firewall points to a conflict between our current theories of spacetime and of quantum mechanics. It may lead to a new understanding of how these are connected, perhaps based on quantum entanglement.
NASA Technical Reports Server (NTRS)
Dolan, Joseph F.; Fisher, Richard R. (Technical Monitor)
2001-01-01
When asked to discuss Cyg XR-1, E. E. Salpeter once concluded, 'A black hole in Cyg X(R)-1 is the most conservative hypothesis.' Recent observations now make it likely that a black hole in Cyg XR-1 is the only hypothesis tenable. Chandrasekhar first showed that compact stars - those with the inward force of gravity on their outer layers balanced by the pressure generated by the Pauli exclusion principle acting on its electrons (in white dwarfs) or nucleons (in neutron stars) - have a maximum mass. Equilibrium is achieved at a minimum of the total energy of the star, which is the sum of the positive Fermi energy and the negative gravitational energy. The maximum mass attainable in equilibrium is found by setting E = 0: M(max) = 1.5 M(Sun). If the mass of the star is larger than this, then E can be decreased without bound by decreasing the star's radius and increasing its (negative) gravitational energy. No equilibrium value of the radius exist, and general relativity predicts that gravitational collapse to a point occurs. This point singularity is a black hole.
Thermal corpuscular black holes
NASA Astrophysics Data System (ADS)
Casadio, Roberto; Giugno, Andrea; Orlandi, Alessio
2015-06-01
We study the corpuscular model of an evaporating black hole consisting of a specific quantum state for a large number N of self-confined bosons. The single-particle spectrum contains a discrete ground state of energy m (corresponding to toy gravitons forming the black hole), and a gapless continuous spectrum (to accommodate for the Hawking radiation with energy ω >m ). Each constituent is in a superposition of the ground state and a Planckian distribution at the expected Hawking temperature in the continuum. We first find that, assuming the Hawking radiation is the leading effect of the internal scatterings, the corresponding N -particle state can be collectively described by a single-particle wave function given by a superposition of a total ground state with energy M =N m and a Planckian distribution for E >M at the same Hawking temperature. From this collective state, we compute the partition function and obtain an entropy which reproduces the usual area law with a logarithmic correction precisely related with the Hawking component. By means of the horizon wave function for the system, we finally show the backreaction of modes with ω >m reduces the Hawking flux. Both corrections, to the entropy and to the Hawking flux, suggest the evaporation properly stops for vanishing mass, if the black hole is in this particular quantum state.
NASA Astrophysics Data System (ADS)
Abel, T.
star. Within this wide range of possible initial masses the death of these star will lead very different remnants (Heger and Woosley 2001). In the case of stars with masses larger than 260 solar mass no metals may be released in black holes are the natural outcome. This may be an interesting possibility to form intermediate mass black holes which are attractive seeds to be nurtured to the super-massive black holes observed in the centers of nearby galaxies. However, no metals would be released and it would prove difficult to understand the transition to the formation of low mass metal enriched population II stars. Stars with masses below 140 solar masses would enrich the intergalactic medium as well as form massive black holes. The coincidence of the Kelvin Helmholtz time with our computed accretion times at about 120 solar masses may argue in favor of such smaller masses. These first black holes may well leave the halos in which they formed for even rather modest kick velocities >~ 10 km/s. Nevertheless, up to about one hundred thousand of these first black holes may remain in the Milky Way. The realization that structure formation began within one hundred million years after big bang makes it difficult to study observationally these first crucial steps. Future observatories have hence to focus on larger collecting areas and wavelengths for which the universe is transparent up to redshifts of 30. XEUS offers the chance to open a new window to these so far dark ages. The limiting masses quoted here rely on stellar models of primordial stars that do not include rotation, magnetic fields or mass loss and hence are somewhat uncertain.
Destroying extremal magnetized black holes
NASA Astrophysics Data System (ADS)
Siahaan, Haryanto M.
2017-07-01
The gedanken experiment by Wald to destroy a black hole using a test particle in the equatorial plane is adapted to the case of extremal magnetized black holes. We find that the presence of external magnetic fields resulting from the "Ernst magnetization" permits a test particle to have strong enough energy to destroy the black hole. However, the corresponding effective potentials show that such particles would never reach the horizon.
NASA Astrophysics Data System (ADS)
Kocsis, Bence; Loeb, Abraham
2014-09-01
Black holes are the ultimate prisons of the Universe, regions of spacetime where the enormous gravity prohibits matter or even light to escape to infinity. Yet, matter falling toward the black holes may shine spectacularly, generating the strongest source of radiation. These sources provide us with astrophysical laboratories of extreme physical conditions that cannot be realized on Earth. This chapter offers a review of the basic menus for feeding matter onto black holes and discusses their observational implications.
NASA Astrophysics Data System (ADS)
Su, Daiqin; Ho, C. T. Marco; Mann, Robert B.; Ralph, Timothy C.
2017-09-01
We show that the gravitational quasinormal modes (QNMs) of a Schwarzschild black hole play the role of a multimode squeezer that can generate particles. For a minimally coupled scalar field, the QNMs "squeeze" the initial state of the scalar field (even for the vacuum) and produce scalar particles. The maximal squeezing amplitude is inversely proportional to the cube of the imaginary part of the QNM frequency, implying that the particle generation efficiency is higher for lower decaying QNMs. Our results show that the gravitational perturbations can amplify Hawking radiation.
Automorphic Black Hole Entropy
NASA Astrophysics Data System (ADS)
Schimmrigk, Rolf
2013-09-01
Over the past few years the understanding of the microscopic theory of black hole entropy has made important conceptual progress by recognizing that the degeneracies are encoded in partition functions which are determined by higher rank automorphic representations, in particular in the context of Siegel modular forms of genus two. In this review, some of the elements of this framework are highlighted. One of the surprising aspects is that the Siegel forms that have appeared in the entropic context are geometric in origin, arising from weight two cusp forms, hence from elliptic curves.
How black holes saved relativity
NASA Astrophysics Data System (ADS)
Prescod-Weinstein, Chanda
2016-02-01
While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.
Acceleration of black hole universe
NASA Astrophysics Data System (ADS)
Zhang, T. X.; Frederick, C.
2014-01-01
Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.
NASA Technical Reports Server (NTRS)
Wanjek, Christopher
2003-01-01
Regardless of size, black holes easily acquire accretion disks. Supermassive black holes can feast on the bountiful interstellar gas in galactic nuclei. Small black holes formed from collapsing stars often belong to binary systems in which a bulging companion star can spill some of its gas into the black hole s reach. In the chaotic mess of the accretion disk, atoms collide with one another. Swirling plasma reaches speeds upward of 10% that of light and glows brightly in many wavebands, particularly in X-rays. Gas gets blown back by a wind of radiation from the inner disk. New material enters the disks from different directions.
Black holes and the multiverse
Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun E-mail: vilenkin@cosmos.phy.tufts.edu
2016-02-01
Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.
Thermodynamics of Accelerating Black Holes
NASA Astrophysics Data System (ADS)
Appels, Michael; Gregory, Ruth; KubizÅák, David
2016-09-01
We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon—even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.
Thermodynamics of Accelerating Black Holes.
Appels, Michael; Gregory, Ruth; Kubizňák, David
2016-09-23
We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.
NASA Astrophysics Data System (ADS)
2002-10-01
Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way
NASA Astrophysics Data System (ADS)
Pasqua, Antonio; Chattopadhyay, Surajit; Assaf, Khudhair A.; Salako, Ines G.
2016-06-01
In this paper, we study the properties of the Holographic Dark Energy (HDE) model in the context of Kaluza-Klein (KK) cosmology with infrared cut-off given by the recently proposed by Granda-Oliveros cut-off, which contains a term proportional to the time derivative of the Hubble parameter and one proportional to the Hubble parameter squared. Moreover, this cut-off is characterized by two free parameters which are the proportional constants of the two terms of the cut-off. We derive the expression of the Equation of State (EoS) parameter ωD and of the deceleration parameter q for both non-interacting and interacting Dark Sectors and in the limiting case of a flat Dark Dominated Universe. Moreover, we study the squared speed of the sound vs2 and the statefinder diagnostic \\{r,s\\} in order to understand the cosmological properties of the model considered. We also develop a correspondence between the model considered and three scalar field models: the tachyon, the k-essence and the quintessence ones.
Photo-production of a 750 GeV di-photon resonance mediated by Kaluza-Klein leptons in the loop
NASA Astrophysics Data System (ADS)
Abel, Steven; Khoze, Valentin V.
2016-05-01
We consider the phenomenology of a 750 GeV resonance X which can be produced at the LHC by only photon fusion and subsequently decay into di-photons. We propose that the spin-zero state X is coupled to a heavy lepton that lives in the bulk of a higher-dimensional theory and interacts only with the photons of the Standard Model. We compute the di-photon rate in these models with two and more compact extra dimensions and demonstrate that they allow for a compelling explanation of the di-photon excess recently observed by the ATLAS and CMS collaborations. The central role in our approach is played by the summation over the Kaluza-Klein modes of the new leptons, thus providing a significant enhancement of the X → γγ loops for the production and decay subprocesses. It is expected that the jet activity accompanying these purely electromagnetic (at the partonic level) processes is numerically suppressed by factors such as {α}_{em}^2{{C}}_{qoverline{q}}/{{C}}_{γ γ}˜ 1{0}^{-3}.
Chang, W.-F.; Ng, John N.; Wu, Jackson M. S.
2009-03-01
We continue our previous study on what are the allowed forms of quark mass matrices in the Randall-Sundrum framework that can reproduce the experimentally observed quark mass spectrum and the pattern of Cabibbo-Kobayashi-Maskawa mixing. We study the constraints the {delta}F=2 processes in the neutral meson sector placed on the admissible forms found there, and we found only the asymmetrical type of quark mass matrices arising from anarchical Yukawa structures remain viable at the few TeV scale reachable at the LHC. We study also the decay of the first Kaluza-Klein (KK) excitation of the gluon. We give the decay branching ratios of the first KK gluon into quark pairs, and we point out that measurements of the decay width and just one of the quark spins in the dominant tt decays can be used to extract the effective coupling of the first KK gluon to top quarks for both chiralities. This provides a further probe into the flavor structure of the Randall-Sundrum framework.
Black-Hole Feedback in Quasars
This animation illustrates how black-hole feedback works in quasars. Dense gas and dust in the center simultaneously fuels the black hole and shrouds it from view. The black-hole wind propels large...
Can Black Hole Relax Unitarily?
NASA Astrophysics Data System (ADS)
Solodukhin, S. N.
2005-03-01
We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.
Numerical Simulation of Black Holes
NASA Astrophysics Data System (ADS)
Teukolsky, Saul
2003-04-01
Einstein's equations of general relativity are prime candidates for numerical solution on supercomputers. There is some urgency in being able to carry out such simulations: Large-scale gravitational wave detectors are now coming on line, and the most important expected signals cannot be predicted except numerically. Problems involving black holes are perhaps the most interesting, yet also particularly challenging computationally. One difficulty is that inside a black hole there is a physical singularity that cannot be part of the computational domain. A second difficulty is the disparity in length scales between the size of the black hole and the wavelength of the gravitational radiation emitted. A third difficulty is that all existing methods of evolving black holes in three spatial dimensions are plagued by instabilities that prohibit long-term evolution. I will describe the ideas that are being introduced in numerical relativity to deal with these problems, and discuss the results of recent calculations of black hole collisions.
Black hole final state conspiracies
NASA Astrophysics Data System (ADS)
McInnes, Brett
2009-01-01
The principle that unitarity must be preserved in all processes, no matter how exotic, has led to deep insights into boundary conditions in cosmology and black hole theory. In the case of black hole evaporation, Horowitz and Maldacena were led to propose that unitarity preservation can be understood in terms of a restriction imposed on the wave function at the singularity. Gottesman and Preskill showed that this natural idea only works if one postulates the presence of “conspiracies” between systems just inside the event horizon and states at much later times, near the singularity. We argue that some AdS black holes have unusual internal thermodynamics, and that this may permit the required “conspiracies” if real black holes are described by some kind of sum over all AdS black holes having the same entropy.
When Charged Black Holes Merge
NASA Astrophysics Data System (ADS)
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
Prisons of Light - Black Holes
NASA Astrophysics Data System (ADS)
Ferguson, Kitty
1998-05-01
In this jargon-free review of one of the most fascinating topics in modern science, acclaimed science writer Kitty Ferguson examines the discovery of black holes, their nature, and what they can teach us about the mysteries of the universe. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light--Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.
Hubeny, V.
2005-01-12
We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.
Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund
2005-02-07
We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.
Hidden Structures of Black Holes
NASA Astrophysics Data System (ADS)
Vercnocke, Bert
2010-11-01
This thesis investigates two main topics concerning black holes in extensions of general relativity inspired by string theory. First, the structure of the equations of motion underlying black hole solutions is considered, in theories of D-dimensional gravity coupled to scalars and vectors. For solutions preserving supersymmetry, the equations of motion have a dramatic simplification: they become first-order instead of the second-order equations one would expect. Recently, it was found that this is a feature some non-supersymmetric black hole solutions exhibit as well. We investigate if this holds more generally, by examining what the conditions are to have first-order equations for the scalar fields of non-supersymmetric black holes, that mimic the form of their supersymmetric counterparts. This is illustrated in examples. Second, the structure of black holes themselves is investigated. String theory has been successful in explaining the Bekenstein-Hawking entropy for (mainly supersymmetric) black holes from a microscopic perspective. However, it is not fully established what the interpretation of the corresponding 'microstates' should be in the gravitational description where the black hole picture is valid. There have been recent advances to understand the nature of black hole microstates in the gravity regime, such as the fuzzball proposal. A related idea says that black hole configurations with multiple centers are related to microstates of single-centered black holes. We report on work relating both pictures. As an aside, a relation between violations of causality for certain spacetimes (presence of closed timelike curves in the geometry) and a breakdown of unitarity in the dual conformal field theory is given.
Are LIGO's Black Holes Made From Smaller Black Holes?
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2017-05-01
The recent successes of the Laser Interferometer Gravitational-Wave Observatory (LIGO) has raised hopes that several long-standing questions in black-hole physics will soon be answerable. Besides revealing how the black-hole binary pairs are built, could detections with LIGO also reveal how the black holes themselves form?Isolation or HierarchyThe first detection of gravitational waves, GW150914, was surprising for a number of reasons. One unexpected result was the mass of the two black holes that LIGO saw merging: they were a whopping 29 and 36 solar masses.On the left of this schematic, two first-generation (direct-collapse) black holes form a merging binary. The right illustrates a second-generation hierarchical merger: each black hole in the final merging binary was formed by the merger of two smaller black holes. [Adapted fromGerosa et al., a simultaneously published paper that also explores the problem of hierarchical mergers and reaches similar conclusions]How do black holes of this size form? One possibility is that they form in isolation from the collapse of a single massive star. In an alternative model, they are created through the hierarchical merger of smaller black holes, gradually building up to the size we observed.A team of scientists led by Maya Fishbach (University of Chicago) suggests that we may soon be able to tell whether or not black holes observed by LIGO formed hierarchically. Fishbach and collaborators argue that hierarchical formation leaves a distinctive signature on the spins of the final black holes and that as soon as we have enough merger detections from LIGO, we can use spin measurements to statistically determine if LIGO black holes were formed hierarchically.Spins from Major MergersWhen two black holes merge, both their original spins and the angular momentum of the pair contribute to the spin of the final black hole that results. Fishbach and collaborators calculate the expected distribution of these final spins assuming that
Magnetic fields around black holes
NASA Astrophysics Data System (ADS)
Garofalo, David A. G.
Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our
Bronnikov, K A; Fabris, J C
2006-06-30
We study self-gravitating, static, spherically symmetric phantom scalar fields with arbitrary potentials (favored by cosmological observations) and single out 16 classes of possible regular configurations with flat, de Sitter, and anti-de Sitter asymptotics. Among them are traversable wormholes, bouncing Kantowski-Sachs (KS) cosmologies, and asymptotically flat black holes (BHs). A regular BH has a Schwarzschild-like causal structure, but the singularity is replaced by a de Sitter infinity, giving a hypothetic BH explorer a chance to survive. It also looks possible that our Universe has originated in a phantom-dominated collapse in another universe, with KS expansion and isotropization after crossing the horizon. Explicit examples of regular solutions are built and discussed. Possible generalizations include k-essence type scalar fields (with a potential) and scalar-tensor gravity.
NASA Astrophysics Data System (ADS)
Schilling, Amanda; Carlton, A. K.; Kashkanova, A.; Kennefick, J.; Kennefick, D.; Seigar, M. S.; Lacy, C. H.; Galaxy Evolution Survey, Arkansas
2010-01-01
We have computed the mass of the central black hole in 145 quasars chosen from the SDSS (Sloan Digital Sky Survey) DR3. The objects were chosen to sample the peak in quasar evolution and have redshifts in the range 1.85 < z < 4.26. Masses were computed using standard gas dynamics techniques with the luminosity at 1350Å and the width (FWHM) of the Doppler broadened Carbon IV emission line. Also, we were able to compare masses calculated from the CIV line with those calculated from the MgII line for one third of our data set. We will discuss how the mass of the SMBHs change over the range of redshifts and how this may be correlated with other quasar properties. This project is funded by a grant from NASA.
Kerr black hole thermodynamical fluctuations
NASA Astrophysics Data System (ADS)
Pavon, D.; Rubi, J. M.
1985-04-01
The near-equilibrium thermodynamical (TD) fluctuations of a massive rotating uncharged Kerr black hole immersed in a uniformly corotating radiation bath at its temperature are investigated theoretically, generalizing Schwarzschild-black-hole analysis of Pavon and Rubi(1983), based on Einstein fluctuation theory. The correlations for the energy and angular moment fluctuations and the second moments of the other TD parameters are obtained, and the generalized second law of black-hole TD and the Bekenstein (1975) interpretation of black-hole entropy are seen as functioning well in this case. A local-stability criterion and relation for TD equilibrium between the Kerr hole and its own radiation in the flat-space-time limit are derived, and a restriction between C and Lambda is deduced.
More Hidden Black Hole Dangers
NASA Technical Reports Server (NTRS)
Wanjek, Christopher
2003-01-01
Black holes such as GRO J1655-40 form from collapsed stars. When stars at least eight times more massive than our Sun exhaust their fuel supply, they no longer have the energy to support their tremendous bulk. These stars explode as supernovae, blasting their outer envelopes into space. If the core is more than three times the mass of the Sun, it will collapse into a singularity, a single point of infinite density.Although light cannot escape black holes, astronomers can see black holes by virtue of the hot, glowing gas often stolen from a neighboring star that orbits these objects. From our vantage point, the light seems to flicker. The Rossi Explorer has recorded this flickering (called quasiperiodic oscillations, or QPOs) around many black holes. QPOs are produced by gas very near the innermost stable orbit the closest orbit a blob of gas can maintain before falling pell-mell into the black hole. As gas whips around the black hole at near light speed, gravity pulls the gas in one direction, then another, adding to the flickering. The QPO is related to the speed and size of this orbit and the mass of the black hole.
More Hidden Black Hole Dangers
NASA Technical Reports Server (NTRS)
Wanjek, Christopher
2003-01-01
Black holes such as GRO J1655-40 form from collapsed stars. When stars at least eight times more massive than our Sun exhaust their fuel supply, they no longer have the energy to support their tremendous bulk. These stars explode as supernovae, blasting their outer envelopes into space. If the core is more than three times the mass of the Sun, it will collapse into a singularity, a single point of infinite density.Although light cannot escape black holes, astronomers can see black holes by virtue of the hot, glowing gas often stolen from a neighboring star that orbits these objects. From our vantage point, the light seems to flicker. The Rossi Explorer has recorded this flickering (called quasiperiodic oscillations, or QPOs) around many black holes. QPOs are produced by gas very near the innermost stable orbit the closest orbit a blob of gas can maintain before falling pell-mell into the black hole. As gas whips around the black hole at near light speed, gravity pulls the gas in one direction, then another, adding to the flickering. The QPO is related to the speed and size of this orbit and the mass of the black hole.
NASA Technical Reports Server (NTRS)
2006-01-01
[figure removed for brevity, see original site] Poster Version
This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end.
The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light.
The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.
Rotating regular black hole solution
NASA Astrophysics Data System (ADS)
Abdujabbarov, Ahmadjon
2016-07-01
Based on the Newman-Janis algorithm, the Ayón-Beato-García spacetime metric [Phys. Rev. Lett. 80, 5056 (1998)] of the regular spherically symmetric, static, and charged black hole has been converted into rotational form. It is shown that the derived solution for rotating a regular black hole is regular and the critical value of the electric charge for which two horizons merge into one sufficiently decreases in the presence of the nonvanishing rotation parameter a of the black hole.
Orbital Resonances Around Black Holes
NASA Astrophysics Data System (ADS)
Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja
2015-02-01
We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.
Black holes and Higgs stability
Tetradis, Nikolaos
2016-09-20
We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.
Vacuum metastability with black holes
NASA Astrophysics Data System (ADS)
Burda, Philipp; Gregory, Ruth; Moss, Ian G.
2015-08-01
We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.
Black Holes: A Traveler's Guide
NASA Astrophysics Data System (ADS)
Pickover, Clifford A.
1998-03-01
BLACK HOLES A TRAVELER'S GUIDE Clifford Pickover's inventive and entertaining excursion beyond the curves of space and time. "I've enjoyed Clifford Pickover's earlier books . . . now he has ventured into the exploration of black holes. All would-be tourists are strongly advised to read his traveler's guide." -Arthur C. Clarke. "Many books have been written about black holes, but none surpass this one in arousing emotions of awe and wonder towards the mysterious structure of the universe." -Martin Gardner. "Bucky Fuller thought big. Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." -Wired. "The book is fun, zany, in-your-face, and refreshingly addictive." -Times Higher Education Supplement.
Gravitational polarizability of black holes
Damour, Thibault; Lecian, Orchidea Maria
2009-08-15
The gravitational polarizability properties of black holes are compared and contrasted with their electromagnetic polarizability properties. The 'shape' or 'height' multipolar Love numbers h{sub l} of a black hole are defined and computed. They are then compared to their electromagnetic analogs h{sub l}{sup EM}. The Love numbers h{sub l} give the height of the lth multipolar 'tidal bulge' raised on the horizon of a black hole by faraway masses. We also discuss the shape of the tidal bulge raised by a test-mass m, in the limit where m gets very close to the horizon.
On regular rotating black holes
NASA Astrophysics Data System (ADS)
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.
NASA Astrophysics Data System (ADS)
Mashian, Natalie; Loeb, Abraham
2017-09-01
We predict the number of black holes with stellar companions that are potentially detectable with Gaia astrometry over the course of its 5-yr mission. Our model estimates that nearly 2 × 105 astrometric binaries hosting black holes and stellar companions brighter than Gaia's detection threshold, G ∼ 20, should be discovered with 5σ sensitivity. Among these detectable binaries, systems with longer orbital periods are favoured, and black hole and stellar companion masses in the range MBH ∼ 6-10 M⊙ and M* ∼ 1-2 M⊙, respectively, are expected to dominate.
NASA Astrophysics Data System (ADS)
Cho, Inyong; Kim, Hyeong-Chan
2017-04-01
We investigate black holes formed by static perfect fluid with p =-ρ /3 . These represent the black holes in S3 and H3 spatial geometries. There are three classes of black-hole solutions, two S3 types and one H3 type. The interesting solution is the S3 type one, which possesses two singularities. One is at the north pole behind the horizon, and the other is naked at the south pole. The observers, however, are free from falling to the naked singularity. There are also nonstatic cosmological solutions in S3 and H3 and a singular static solution in H3.
Orbital resonances around black holes.
Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja
2015-02-27
We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.
Quantum mechanics of black holes.
Witten, Edward
2012-08-03
The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.
Erratic Black Hole Regulates Itself
NASA Astrophysics Data System (ADS)
2009-03-01
New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don
NASA Astrophysics Data System (ADS)
van Herck, Walter; Wyder, Thomas
2010-04-01
The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.
Braneworld Black Hole Gravitational Lensing
NASA Astrophysics Data System (ADS)
Liang, Jun
2017-04-01
A class of braneworld black holes, which I called as Bronnikov-Melnikov-Dehen (BMD) black holes, are studied as gravitational lenses. I obtain the deflection angle in the strong deflection limit, and further calculate the angular positions and magnifications of relativistic images as well as the time delay between different relativistic images. I also compare the results with those obtained for Schwarzschild and two braneworld black holes, i.e., the tidal Reissner-Nordström (R-N) and the Casadio-Fabbri-Mazzacurati (CFM) black holes. Supported by Natural Science Foundation of Education Department of Shannxi Provincial Government under Grant No. 15JK1077, and Doctorial Scientific Research Starting Fund of Shannxi University of Science and Technology under Grant No. BJ12-02
The first supermassive black holes
NASA Astrophysics Data System (ADS)
Smith, Aaron; Bromm, Volker; Loeb, Abraham
2017-01-01
We briefly review the historical development of the ideas regarding the first supermassive black hole seeds, the physics of their formation and radiative feedback, recent theoretical and observational progress, and our outlook for the future.
NASA Astrophysics Data System (ADS)
Zhang, Tianxi
2014-06-01
The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin
Analytical Relativity of Black Holes
NASA Astrophysics Data System (ADS)
Damour, Thibault
The successful detection and analysis of gravitational wave (GW) signals from coalescing binary black holes necessitates the accurate prior knowledge of the form of the GW signals. This knowledge can be acquired through a synergy between Analytical Relativity (AR) methods and Numerical Relativity (NR) ones. We describe here the most promising AR formalism for describing the motion and radiation of coalescing binary black holes, the Effective One Body (EOB) method, and discuss its comparison with NR simulations.
Black holes from extended inflation
NASA Astrophysics Data System (ADS)
Hsu, Stephen D. H.
1990-11-01
It is argued that models of extended inflation, in which modified Einstein gravity allows a graceful exit from the false vacuum, lead to copious production of black holes. The critical temperature of the inflationary phase transition must be > 108 GeV in order to avoid severe cosmological problems in a universe dominated by black holes. We speculate on the possibility that the interiors of false vacuum regions evolve into baby universes.
NASA Astrophysics Data System (ADS)
Corda, Christian
2013-12-01
Introducing a black hole (BH) effective temperature, which takes into account both the non-strictly thermal character of Hawking radiation and the countable behavior of emissions of subsequent Hawking quanta, we recently re-analysed BH quasi-normal modes (QNMs) and interpreted them naturally in terms of quantum levels. In this work we improve such an analysis removing some approximations that have been implicitly used in our previous works and obtaining the corrected expressions for the formulas of the horizon's area quantization and the number of quanta of area and hence also for Bekenstein-Hawking entropy, its subleading corrections and the number of micro-states, i.e. quantities which are fundamental to realize the underlying quantum gravity theory, like functions of the QNMs quantum "overtone" number n and, in turn, of the BH quantum excited level. An approximation concerning the maximum value of n is also corrected. On the other hand, our previous results were strictly corrected only for scalar and gravitational perturbations. Here we show that the discussion holds also for vector perturbations. The analysis is totally consistent with the general conviction that BHs result in highly excited states representing both the "hydrogen atom" and the "quasi-thermal emission" in quantum gravity. Our BH model is somewhat similar to the semi-classical Bohr's model of the structure of a hydrogen atom. The thermal approximation of previous results in the literature is consistent with the results in this paper. In principle, such results could also have important implications for the BH information paradox.
Rethinking Black Hole Accretion Discs
NASA Astrophysics Data System (ADS)
Salvesen, Greg
Accretion discs are staples of astrophysics. Tapping into the gravitational potential energy of the accreting material, these discs are highly efficient machines that produce copious radiation and extreme outflows. While interesting in their own right, accretion discs also act as tools to study black holes and directly influence the properties of the Universe. Black hole X-ray binaries are fantastic natural laboratories for studying accretion disc physics and black hole phenomena. Among many of the curious behaviors exhibited by these systems are black hole state transitions -- complicated cycles of dramatic brightening and dimming. Using X-ray observations with high temporal cadence, we show that the evolution of the accretion disc spectrum during black hole state transitions can be described by a variable disc atmospheric structure without invoking a radially truncated disc geometry. The accretion disc spectrum can be a powerful diagnostic for measuring black hole spin if the effects of the disc atmosphere on the emergent spectrum are well-understood; however, properties of the disc atmosphere are largely unconstrained. Using statistical methods, we decompose this black hole spin measurement technique and show that modest uncertainties regarding the disc atmosphere can lead to erroneous spin measurements. The vertical structure of the disc is difficult to constrain due to our ignorance of the contribution to hydrostatic balance by magnetic fields, which are fundamental to the accretion process. Observations of black hole X-ray binaries and the accretion environments near supermassive black holes provide mounting evidence for strong magnetization. Performing numerical simulations of accretion discs in the shearing box approximation, we impose a net vertical magnetic flux that allows us to effectively control the level of disc magnetization. We study how dynamo activity and the properties of turbulence driven by the magnetorotational instability depend on the
Violent flickering in Black Holes
NASA Astrophysics Data System (ADS)
2008-10-01
Unique observations of the flickering light from the surroundings of two black holes provide new insights into the colossal energy that flows at their hearts. By mapping out how well the variations in visible light match those in X-rays on very short timescales, astronomers have shown that magnetic fields must play a crucial role in the way black holes swallow matter. Flickering black hole ESO PR Photo 36/08 Flickering black hole Like the flame from a candle, light coming from the surroundings of a black hole is not constant -- it flares, sputters and sparkles. "The rapid flickering of light from a black hole is most commonly observed at X-ray wavelengths," says Poshak Gandhi, who led the international team that reports these results. "This new study is one of only a handful to date that also explore the fast variations in visible light, and, most importantly how these fluctuations relate to those in X-rays." The observations tracked the shimmering of the black holes simultaneously using two different instruments, one on the ground and one in space. The X-ray data were taken using NASA's Rossi X-ray Timing Explorer satellite. The visible light was collected with the high speed camera ULTRACAM, a visiting instrument at ESO's Very Large Telescope (VLT), recording up to 20 images a second. ULTRACAM was developed by team members Vik Dhillon and Tom Marsh. "These are among the fastest observations of a black hole ever obtained with a large optical telescope," says Dhillon. To their surprise, astronomers discovered that the brightness fluctuations in the visible light were even more rapid than those seen in X-rays. In addition, the visible-light and X-ray variations were found not to be simultaneous, but to follow a repeated and remarkable pattern: just before an X-ray flare the visible light dims, and then surges to a bright flash for a tiny fraction of a second before rapidly decreasing again. None of this radiation emerges directly from the black hole, but from the
NASA Astrophysics Data System (ADS)
Holdom, Bob; Ren, Jing
2017-04-01
Astrophysical black hole candidates, although long thought to have a horizon, could be horizonless ultracompact objects. This intriguing possibility is motivated by the black hole information paradox and a plausible fundamental connection with quantum gravity. Asymptotically free quadratic gravity is considered here as the UV completion of general relativity. A classical theory that captures its main features is used to search for solutions as sourced by matter. We find that sufficiently dense matter produces a novel horizonless configuration, the 2-2-hole, which closely matches the exterior Schwarzschild solution down to about a Planck proper length of the would-be horizon. The 2-2-hole is characterized by an interior with a shrinking volume and a seemingly innocuous timelike curvature singularity. The interior also has a novel scaling behavior with respect to the physical mass of the 2-2-hole. This leads to an extremely deep gravitational potential in which particles get efficiently trapped via collisions. As a generic static solution, the 2-2-hole may then be the nearly black end point of gravitational collapse. There is a considerable time delay for external probes of the 2-2-hole interior, and this determines the spacing of echoes in a postmerger gravitational wave signal.
NASA Astrophysics Data System (ADS)
2010-07-01
Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help
A general glance at theoretical black holes
NASA Astrophysics Data System (ADS)
Chia, Han-Yu
This thesis is a general review based on the materials of black hole physics that ordinary graduate course such as the General Relativity and Cosmology do not cover. The thesis mainly covers the studies of four-dimensional black holes and black hole thermodynamics. Then, a brief discussion on higher dimensional black holes of Kerr-Schwarzschild class follows. Advanced topics in higher dimensional black holes are also discussed in the thesis. Those advanced topics include extra dimension, black hole production in particle accelerators and evaporation in both colliders and atmosphere.
Higher-dimensional lifts of Killing-Yano forms with torsion
NASA Astrophysics Data System (ADS)
Chow, David D. K.
2017-01-01
Using a Kaluza-Klein-type lift, it is shown how Killing-Yano forms with torsion can remain symmetries of a higher-dimensional geometry, subject to an algebraic condition between the Kaluza-Klein field strength and the Killing-Yano form. The lift condition’s significance is highlighted, and is satisfied by examples of black holes in supergravity.
Evaporation of Primordial Black Holes
NASA Astrophysics Data System (ADS)
Hawking, S. W.
The usual explanation of the isotropy of the universe is that inflation would have smoothed out any inhomogeneities. However, if the universe was initially fractal or in a foam like state, an overall inflation would have l it in the same state. I suggest that the universe did indeed begin with a tangled web of wormholes connecting pairs of black holes but that the inflationary expansion was unstable: wormholes that are slightly smaller correspond to black holes that are hotter than the cosmological background and evaporate away. This picture is supported by calculations with Raphael Bousso of the evaporation of primordial black holes in the s-wave and large
NASA Astrophysics Data System (ADS)
Christodoulou, Marios; De Lorenzo, Tommaso
2016-11-01
Black holes that have nearly evaporated are often thought of as small objects, due to their tiny exterior area. However, the horizon bounds large spacelike hypersurfaces. A compelling geometric perspective on the evolution of the interior geometry was recently shown to be provided by a generally covariant definition of the volume inside a black hole using maximal surfaces. In this article, we expand on previous results and show that finding the maximal surfaces in an arbitrary spherically symmetric spacetime is equivalent to a 1 +1 geodesic problem. We then study the effect of Hawking radiation on the volume by computing the volume of maximal surfaces inside the apparent horizon of an evaporating black hole as a function of time at infinity: while the area is shrinking, the volume of these surfaces grows monotonically with advanced time, up to when the horizon has reached Planckian dimensions. The physical relevance of these results for the information paradox and the remnant scenarios are discussed.
Scrambling with matrix black holes
NASA Astrophysics Data System (ADS)
Brady, Lucas; Sahakian, Vatche
2013-08-01
If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.
Quantum Criticality and Black Holes
Sachdev, Subir [Harvard University, Cambridge, Massachusetts, United States
2016-07-12
I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.
Quantum Criticality and Black Holes
Sachdev, Subir
2007-08-22
I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.
NASA Astrophysics Data System (ADS)
Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu
2017-01-01
We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.
The Black Hole Information Problem
NASA Astrophysics Data System (ADS)
Polchinski, Joseph
The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas. Presented at the 2014-15 Jerusalem Winter School and the 2015 TASI.
NASA Astrophysics Data System (ADS)
Fan, Zhong-Ying
2016-09-01
In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.
Begelman, Mitchell C.
2012-04-10
We propose that the growth of supermassive black holes is associated mainly with brief episodes of highly super-Eddington infall of gas ({sup h}yperaccretion{sup )}. This gas is not swallowed in real time, but forms an envelope of matter around the black hole that can be swallowed gradually, over a much longer timescale. However, only a small fraction of the black hole mass can be stored in the envelope at any one time. We argue that any infalling matter above a few percent of the hole's mass is ejected as a result of the plunge in opacity at temperatures below a few thousand degrees kelvin, corresponding to the Hayashi track. The speed of ejection of this matter, compared to the velocity dispersion {sigma} of the host galaxy's core, determines whether the ejected matter is lost forever or returns eventually to rejoin the envelope, from which it can be ultimately accreted. The threshold between matter recycling and permanent loss defines a relationship between the maximum black hole mass and {sigma} that resembles the empirical M{sub BH}-{sigma} relation.
Building black holes: supercomputer cinema.
Shapiro, S L; Teukolsky, S A
1988-07-22
A new computer code can solve Einstein's equations of general relativity for the dynamical evolution of a relativistic star cluster. The cluster may contain a large number of stars that move in a strong gravitational field at speeds approaching the speed of light. Unstable star clusters undergo catastrophic collapse to black holes. The collapse of an unstable cluster to a supermassive black hole at the center of a galaxy may explain the origin of quasars and active galactic nuclei. By means of a supercomputer simulation and color graphics, the whole process can be viewed in real time on a movie screen.
NASA Astrophysics Data System (ADS)
2010-07-01
Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help
Supersymmetric black holes and Freudenthal duality
NASA Astrophysics Data System (ADS)
Marrani, Alessio; Mandal, Taniya; Tripathy, Prasanta K.
2017-07-01
We study the effect of Freudenthal duality on supersymmetric extremal black hole attractors in 𝒩 = 2, D = 4 ungauged supergravity. Freudenthal duality acts on the dyonic black hole charges as an anti-involution which keeps the black hole entropy and the critical points of the effective black hole potential invariant. We analyze its effect on the recently discovered distinct, mutually exclusive phases of axionic supersymmetric black holes, related to the existence of nontrivial involutory constant matrices. In particular, we consider a supersymmetric D0 - D4 - D6 black hole and we explicitly Freudenthal-map it to a supersymmetric D0 - D2 - D4 - D6 black hole. We thus show that the charge representation space of a supersymmetric D0 - D2 - D4 - D6 black hole also contains mutually exclusive domains.
Spin distribution of primordial black holes
NASA Astrophysics Data System (ADS)
Chiba, Takeshi; Yokoyama, Shuichiro
2017-08-01
We estimate the spin distribution of primordial black holes based on the recent study of the critical phenomena in the gravitational collapse of a rotating radiation fluid. We find that primordial black holes are mostly slowly rotating.
Two Monster Black Holes at Work
Zoom into Markarian 739, a nearby galaxy hosting two monster black holes. Using NASA's Swift and Chandra, astronomers have shown that both black holes are producing energy as gas falls into them. T...
Astronomy: Intermediate-mass black hole found
NASA Astrophysics Data System (ADS)
Gültekin, Kayhan
2017-02-01
The existence of medium-sized black holes has long been debated. Such an object has now been discovered in the centre of a dense cluster of stars, potentially enhancing our understanding of all black holes. See Letter p.203
How to Spot a Primitive Black Hole
2010-03-17
These two data plots from NASA Spitzer Space Telescope show a primitive supermassive black hole top compared to a typical one; usually, dust tori are missing and only gas disks are observed in primitive black holes.
Fenimore, Edward E.
2014-10-06
Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.
Black Holes: A Selected Bibliography.
ERIC Educational Resources Information Center
Fraknoi, Andrew
1991-01-01
Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…
Gravitational Collapse and Black Holes
ERIC Educational Resources Information Center
Ryder, Lewis
1973-01-01
The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)
Prisons of Light - Black Holes
NASA Astrophysics Data System (ADS)
Ferguson, Kitty
1998-02-01
Prologue; 1. A cosmic case of burnout; 2. Matters of gravity: Newton and Einstein; 3. The capture of light; 4. Tripping the theoretical fantastic; 5. Crossing the bar; 6. Contemplating an enormous nothing; 7. Evidence in the case; 8. Hearts of darkness; 9. The search goes on; 10. Passages into the labyrinth; 11. Black hole legends and far out ideas; Epilogue.
Gravitational Collapse and Black Holes
ERIC Educational Resources Information Center
Ryder, Lewis
1973-01-01
The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)
Black Holes: A Selected Bibliography.
ERIC Educational Resources Information Center
Fraknoi, Andrew
1991-01-01
Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…
'Black holes': escaping the void.
Waldron, Sharn
2013-02-01
The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche. © 2013, The Society of Analytical Psychology.
NASA Astrophysics Data System (ADS)
Costa, Miguel S.; Greenspan, Lauren; Penedones, João; Santos, Jorge E.
2017-06-01
We numerically construct asymptotically AdS 4 solutions to Einstein-Maxwell-dilaton theory. These have a dipolar electrostatic potential turned on at the conformal boundary {S}^2× {\\mathbb{R}}_t . We find two classes of geometries: AdS soliton solutions that encode the full backreaction of the electric field on the AdS geometry without a horizon, and neutral black holes that are "polarised" by the dipolar potential. For a certain range of the electric field \\mathcal{E} , we find two distinct branches of the AdS soliton that exist for the same value of \\mathcal{E} . For the black hole, we find either two or four branches depending on the value of the electric field and horizon temperature. These branches meet at critical values of the electric field and impose a maximum value of \\mathcal{E} that should be reflected in the dual field theory. For both the soliton and black hole geometries, we study boundary data such as the stress tensor. For the black hole, we also consider horizon observables such as the entropy. At finite temperature, we consider the Gibbs free energy for both phases and determine the phase transition between them. We find that the AdS soliton dominates at low temperature for an electric field up to the maximum value. Using the gauge/gravity duality, we propose that these solutions are dual to deformed ABJM theory and compute the corresponding weak coupling phase diagram.
Resource Letter BH-1: Black Holes.
ERIC Educational Resources Information Center
Detweiler, Steven
1981-01-01
Lists resources on black holes, including: (1) articles of historical interest; (2) books and journal articles on elementary expositions; (3) elementary and advanced textbooks; and (4) research articles on analytic structure of black holes, black hole dynamics, and astrophysical processes. (SK)
Compensating Scientism through "The Black Hole."
ERIC Educational Resources Information Center
Roth, Lane
The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for…
Horndeski scalar-tensor black hole geodesics
NASA Astrophysics Data System (ADS)
Tretyakova, Darya; Melkoserov, Dmitry; Adyev, Timur
2016-10-01
We examine massive particles and null geodesics for the scalar-tensor black hole in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits, corresponding to circular and elliptic orbits, are absent for the black hole solution with the static scalar field. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations.
Gravitational Lensing of STU Black Holes
NASA Astrophysics Data System (ADS)
Saadat, H.
2013-12-01
In this paper we study gravitational lensing by STU black holes. We considered extremal limit of two special cases of zero-charged and one-charged black holes, and obtain the deflection angle. We find that the black hole charge increases the deflection angle.
Resource Letter BH-1: Black Holes.
ERIC Educational Resources Information Center
Detweiler, Steven
1981-01-01
Lists resources on black holes, including: (1) articles of historical interest; (2) books and journal articles on elementary expositions; (3) elementary and advanced textbooks; and (4) research articles on analytic structure of black holes, black hole dynamics, and astrophysical processes. (SK)
Signatures of black holes at the LHC
NASA Astrophysics Data System (ADS)
Cavaglià, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.
2007-06-01
Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.
Compensating Scientism through "The Black Hole."
ERIC Educational Resources Information Center
Roth, Lane
The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for…
Charged black hole horizons and QED effects
NASA Astrophysics Data System (ADS)
Thompson, Johnathon; Muñoz, Gerardo
2017-09-01
It is well known that the presence of quantum fields alters many of the classical properties of black holes. In this paper we consider the lowest-order QED corrections to the location and temperature of the event horizons of charged black holes. We conjecture that QED effects protect realistic charged black holes from the phenomenon of mass inflation.
Information retrieval from black holes
NASA Astrophysics Data System (ADS)
Lochan, Kinjalk; Chakraborty, Sumanta; Padmanabhan, T.
2016-08-01
It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge, and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semiclassically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation nonthermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show how one can decipher the information about the in-state of the field from these distortions. We show that the distortions of a particular kind—which we call nonvacuum distortions—can be used to fully reconstruct the initial data. The asymptotic observer can do this operationally by measuring certain well-defined observables of the quantum field at late times. We demonstrate that a general class of in-states encode all their information content in the correlation of late time out-going modes. Further, using a 1 +1 dimensional dilatonic black hole model to accommodate backreaction self-consistently, we show that observers can also infer and track the information content about the initial data, during the course of evaporation, unambiguously. Implications of such information extraction are discussed.
Black holes as parts of entangled systems
NASA Astrophysics Data System (ADS)
Basini, G.; Capozziello, S.; Longo, G.
A possible link between EPR-type quantum phenomena and astrophysical objects like black holes, under a new general definition of entanglement, is established. A new approach, involving backward time evolution and topology changes, is presented bringing to a definition of the system black hole-worm hole-white hole as an entangled system.
Black hole mimickers: Regular versus singular behavior
Lemos, Jose P. S.; Zaslavskii, Oleg B.
2008-07-15
Black hole mimickers are possible alternatives to black holes; they would look observationally almost like black holes but would have no horizon. The properties in the near-horizon region where gravity is strong can be quite different for both types of objects, but at infinity it could be difficult to discern black holes from their mimickers. To disentangle this possible confusion, we examine the near-horizon properties, and their connection with far away asymptotic properties, of some candidates to black mimickers. We study spherically symmetric uncharged or charged but nonextremal objects, as well as spherically symmetric charged extremal objects. Within the uncharged or charged but nonextremal black hole mimickers, we study nonextremal {epsilon}-wormholes on the threshold of the formation of an event horizon, of which a subclass are called black foils, and gravastars. Within the charged extremal black hole mimickers we study extremal {epsilon}-wormholes on the threshold of the formation of an event horizon, quasi-black holes, and wormholes on the basis of quasi-black holes from Bonnor stars. We elucidate whether or not the objects belonging to these two classes remain regular in the near-horizon limit. The requirement of full regularity, i.e., finite curvature and absence of naked behavior, up to an arbitrary neighborhood of the gravitational radius of the object enables one to rule out potential mimickers in most of the cases. A list ranking the best black hole mimickers up to the worst, both nonextremal and extremal, is as follows: wormholes on the basis of extremal black holes or on the basis of quasi-black holes, quasi-black holes, wormholes on the basis of nonextremal black holes (black foils), and gravastars. Since in observational astrophysics it is difficult to find extremal configurations (the best mimickers in the ranking), whereas nonextremal configurations are really bad mimickers, the task of distinguishing black holes from their mimickers seems to
Gamma ray bursts of black hole universe
NASA Astrophysics Data System (ADS)
Zhang, T. X.
2015-07-01
Slightly modifying the standard big bang theory, Zhang recently developed a new cosmological model called black hole universe, which has only a single postulate but is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain existing observations of the universe. In the previous studies, we have explained the origin, structure, evolution, expansion, cosmic microwave background radiation, quasar, and acceleration of black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates gamma ray bursts of black hole universe and provides an alternative explanation for the energy and spectrum measurements of gamma ray bursts according to the black hole universe model. The results indicate that gamma ray bursts can be understood as emissions of dynamic star-like black holes. A black hole, when it accretes its star or merges with another black hole, becomes dynamic. A dynamic black hole has a broken event horizon and thus cannot hold the inside hot (or high-frequency) blackbody radiation, which flows or leaks out and produces a GRB. A star when it collapses into its core black hole produces a long GRB and releases the gravitational potential energy of the star as gamma rays. A black hole that merges with another black hole produces a short GRB and releases a part of their blackbody radiation as gamma rays. The amount of energy obtained from the emissions of dynamic star-like black holes are consistent with the measurements of energy from GRBs. The GRB energy spectra derived from this new emission mechanism are also consistent with the measurements.
Chandra Catches "Piranha" Black Holes
NASA Astrophysics Data System (ADS)
2007-07-01
Supermassive black holes have been discovered to grow more rapidly in young galaxy clusters, according to new results from NASA's Chandra X-ray Observatory. These "fast-track" supermassive black holes can have a big influence on the galaxies and clusters that they live in. Using Chandra, scientists surveyed a sample of clusters and counted the fraction of galaxies with rapidly growing supermassive black holes, known as active galactic nuclei (or AGN). The data show, for the first time, that younger, more distant galaxy clusters contained far more AGN than older, nearby ones. Galaxy clusters are some of the largest structures in the Universe, consisting of many individual galaxies, a few of which contain AGN. Earlier in the history of the universe, these galaxies contained a lot more gas for star formation and black hole growth than galaxies in clusters do today. This fuel allows the young cluster black holes to grow much more rapidly than their counterparts in nearby clusters. Illustration of Active Galactic Nucleus Illustration of Active Galactic Nucleus "The black holes in these early clusters are like piranha in a very well-fed aquarium," said Jason Eastman of Ohio State University (OSU) and first author of this study. "It's not that they beat out each other for food, rather there was so much that all of the piranha were able to really thrive and grow quickly." The team used Chandra to determine the fraction of AGN in four different galaxy clusters at large distances, when the Universe was about 58% of its current age. Then they compared this value to the fraction found in more nearby clusters, those about 82% of the Universe's current age. The result was the more distant clusters contained about 20 times more AGN than the less distant sample. AGN outside clusters are also more common when the Universe is younger, but only by factors of two or three over the same age span. "It's been predicted that there would be fast-track black holes in clusters, but we never
Black Holes, Thermodynamics, and Quantum Theory
NASA Astrophysics Data System (ADS)
Wald, Robert
2017-01-01
A black hole is a region of ``no escape'' that remains behind after a body has undergone complete gravitational collapse. It is truly remarkable that (i) black holes obey the ordinary laws of thermodynamics, (ii) the entropy of a black hole is given by a simple formula involving geometrical properties of its event horizon, and (iii) quantum theory plays an essential role in the thermodynamic properties of black holes. In this talk, I will review some of the key developments related to these properties of black holes, which fascinated me as a graduate student and continue to fascinate me now.
Noncritical superstring-black hole transition
Parnachev, Andrei; Sahakyan, David A.
2006-04-15
An interesting case of string/black hole transition occurs in two-dimensional noncritical string theory dressed with a compact CFT. In these models the high energy densities of states of perturbative strings and black holes have the same leading behavior when the Hawking temperature of the black hole is equal to the Hagedorn temperature of perturbative strings. We compare the first subleading terms in the black hole and closed string entropies in this setting and argue that the entropy interpolates between these expressions as the energy is varied. We compute the subleading correction to the black hole entropy for a specific simple model.
Black hole Meissner effect and entanglement
NASA Astrophysics Data System (ADS)
Penna, Robert F.
2014-08-01
Extremal black holes tend to expel magnetic and electric fields. Fields are unable to reach the horizon because the length of the black hole throat blows up in the extremal limit. The length of the throat is related to the amount of entanglement between modes on either side of the horizon. So it is natural to try to relate the black hole Meissner effect to entanglement. We derive the black hole Meissner effect directly from the low temperature limit of two-point functions in the Hartle-Hawking vacuum. Then we discuss several new examples of the black hole Meissner effect, its applications to astrophysics, and its relationship to gauge invariance.
Black holes escaping from domain walls
Flachi, Antonino; Sasaki, Misao; Pujolas, Oriol; Tanaka, Takahiro
2006-06-15
Previous studies concerning the interaction of branes and black holes suggested that a small black hole intersecting a brane may escape via a mechanism of reconnection. Here we consider this problem by studying the interaction of a small black hole and a domain wall composed of a scalar field and simulate the evolution of this system when the black hole acquires an initial recoil velocity. We test and confirm previous results, however, unlike the cases previously studied, in the more general set-up considered here, we are able to follow the evolution of the system also during the separation, and completely illustrate how the escape of the black hole takes place.
Black Holes Shed Light on Galaxy Formation
NASA Technical Reports Server (NTRS)
2000-01-01
This videotape is comprised of several segments of animations on black holes and galaxy formation, and several segments of an interview with Dr. John Kormendy. The animation segments are: (1) a super massive black hole, (2) Centarus A active black hole found in a collision, (3) galaxy NGC-4261 (active black hole and jet model), (4) galaxy M-32 (orbits of stars are effected by the gravity of the black hole), (5) galaxy M-37 (motion of stars increases as mass of black hole increases), (6) Birth of active galactic nuclei, (7) the collision of two galaxy leads to merger of the black holes, (8) Centarus A and simulation of the collision of 2 galaxies. There are also several segments of an interview with John Kormendy. In these segments he discusses the two most important aspects of his recent black hole work: (1) the correlations between galaxies speed and the mass of the black holes, and (2) the existence of black holes and galactic formation. He also discusses the importance of the Hubble Space Telescope and the Space Telescope Imaging Spectrograph to the study of black holes. He also shows the methodology of processing images from the spectrograph in his office.
Black Holes Shed Light on Galaxy Formation
NASA Technical Reports Server (NTRS)
2000-01-01
This videotape is comprised of several segments of animations on black holes and galaxy formation, and several segments of an interview with Dr. John Kormendy. The animation segments are: (1) a super massive black hole, (2) Centarus A active black hole found in a collision, (3) galaxy NGC-4261 (active black hole and jet model), (4) galaxy M-32 (orbits of stars are effected by the gravity of the black hole), (5) galaxy M-37 (motion of stars increases as mass of black hole increases), (6) Birth of active galactic nuclei, (7) the collision of two galaxy leads to merger of the black holes, (8) Centarus A and simulation of the collision of 2 galaxies. There are also several segments of an interview with John Kormendy. In these segments he discusses the two most important aspects of his recent black hole work: (1) the correlations between galaxies speed and the mass of the black holes, and (2) the existence of black holes and galactic formation. He also discusses the importance of the Hubble Space Telescope and the Space Telescope Imaging Spectrograph to the study of black holes. He also shows the methodology of processing images from the spectrograph in his office.
Strong gravitational lensing by Kiselev black hole
NASA Astrophysics Data System (ADS)
Younas, Azka; Jamil, Mubasher; Bahamonde, Sebastian; Hussain, Saqib
2015-10-01
We investigate the gravitational lensing scenario due to Schwarzschild-like black hole surrounded by quintessence (Kiselev black hole). We work for the special case of Kiselev black hole where we take the state parameter wq=-2/3 . For the detailed derivation and analysis of the bending angle involved in the deflection of light, we discuss three special cases of Kiselev black hole: nonextreme, extreme, and naked singularity. We also calculate the approximate bending angle and compare it with the exact bending angle. We found the relation of bending angles in the decreasing order as: naked singularity, extreme Kiselev black hole, nonextreme Kiselev black hole, and Schwarzschild black hole. In the weak field approximation, we compute the position and total magnification of relativistic images as well.
Collision of two rotating Hayward black holes
NASA Astrophysics Data System (ADS)
Gwak, Bogeun
2017-07-01
We investigate the spin interaction and the gravitational radiation thermally allowed in a head-on collision of two rotating Hayward black holes. The Hayward black hole is a regular black hole in a modified Einstein equation, and hence it can be an appropriate model to describe the extent to which the regularity effect in the near-horizon region affects the interaction and the radiation. If one black hole is assumed to be considerably smaller than the other, the potential of the spin interaction can be analytically obtained and is dependent on the alignment of angular momenta of the black holes. For the collision of massive black holes, the gravitational radiation is numerically obtained as the upper bound by using the laws of thermodynamics. The effect of the Hayward black hole tends to increase the radiation energy, but we can limit the effect by comparing the radiation energy with the gravitational waves GW150914 and GW151226.
Quantum information erasure inside black holes
NASA Astrophysics Data System (ADS)
Lowe, David A.; Thorlacius, Larus
2015-12-01
An effective field theory for infalling observers in the vicinity of a quasi-static black hole is given in terms of a freely falling lattice discretization. The lattice model successfully reproduces the thermal spectrum of outgoing Hawking radiation, as was shown by Corley and Jacobson, but can also be used to model observations made by a typical low-energy observer who enters the black hole in free fall at a prescribed time. The explicit short distance cutoff ensures that, from the viewpoint of the infalling observer, any quantum information that entered the black hole more than a scrambling time earlier has been erased by the black hole singularity. This property, combined with the requirement that outside observers need at least of order the scrambling time to extract quantum information from the black hole, ensures that a typical infalling observer does not encounter drama upon crossing the black hole horizon in a theory where black hole information is preserved for asymptotic observers.
Some Simple Black Hole Thermodynamics
NASA Astrophysics Data System (ADS)
Lopresto, Michael C.
2003-05-01
In his recent popular book The Universe in a Nutshell, Steven Hawking gives expressions for the entropy1 and temperature (often referred to as the ``Hawking temperature''2 ) of a black hole:3 S = kc34ℏG A T = ℏc38πkGM, where A is the area of the event horizon, M is the mass, k is Boltzmann's constant, ℏ = h2π (h being Planck's constant), c is the speed of light, and G is the universal gravitational constant. These expressions can be used as starting points for some interesting approximations on the thermodynamics of a Schwarzschild black hole, of mass M, which by definition is nonrotating and spherical with an event horizon of radius R = 2GMc2.4,5
Close supermassive binary black holes.
Gaskell, C Martin
2010-01-07
It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive black-hole binary (SMBB). The AGN J1536+0441 ( = SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that J1536+0441 is an example of line emission from a disk. If this is correct, the lack of clear optical spectral evidence for close SMBBs is significant, and argues either that the merging of close SMBBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.
Black holes in magnetic monopoles
NASA Technical Reports Server (NTRS)
Lee, Kimyeong; Nair, V. P.; Weinberg, Erick J.
1991-01-01
We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs field vacuum expectation value v is less than or equal to a critical value v sub cr, which is of the order of the Planck mass. In the limiting case, the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordstrom solution. For v less than v sub cr, we find additional solutions which are singular at f = 0, but which have this singularity hidden within a horizon. These have nontrivial matter fields outside the horizon, and may be interpreted as small black holes lying within a magnetic monopole. The nature of these solutions as a function of v and of the total mass M and their relation to the Reissner-Nordstrom solutions is discussed.
Complexity, action, and black holes
Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying
2016-04-18
In an earlier paper "Complexity Equals Action" we conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.
Complexity, action, and black holes
NASA Astrophysics Data System (ADS)
Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying
2016-04-01
Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the "Wheeler-DeWitt" patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.
NASA Astrophysics Data System (ADS)
Kováčik, Samuel
2017-08-01
We study a black hole with a blurred mass density instead of a singular one, which is caused by the noncommutativity of three-space. Depending on its mass, such object has either none, one or two event horizons. It possesses properties, which become important on a microscopic scale, in particular, the Hawking temperature does not increase indefinitely as the mass goes to zero, but vanishes instead. Such frozen and extremely dense pieces of matter are good dark matter candidates.
Complexity, action, and black holes
Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying
2016-04-18
In an earlier paper "Complexity Equals Action" we conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.
Quantum chaos inside black holes
NASA Astrophysics Data System (ADS)
Addazi, Andrea
2017-06-01
We show how semiclassical black holes can be reinterpreted as an effective geometry, composed of a large ensemble of horizonless naked singularities (eventually smoothed at the Planck scale). We call these new items frizzy-balls, which can be rigorously defined by Euclidean path integral approach. This leads to interesting implications about information paradoxes. We demonstrate that infalling information will chaotically propagate inside this system before going to the full quantum gravity regime (Planck scale).
Kronos: Mapping Black Hole Environments
NASA Astrophysics Data System (ADS)
Peterson, B. M.; Kronos Science Team
2001-12-01
Kronos initiates a new era in astrophysics, fully opening the domain of time to astrophysical study. By using the natural variability of accreting sources, Kronos creates microarcsecond maps of the environments of supermassive black holes in galaxies and stellar-size black holes in binary systems and characterizes accretion processes in Galactic compact binaries. Kronos will obtain broad energy range spectroscopic data with co-aligned X-ray, ultraviolet, and visible spectrometers. The high-Earth orbit of Kronos enables well-sampled high time-resolution observations, critical for the innovative and sophisticated methods that are used to understand the accretion flows, mass outflows, jets, and other phenomena found in accreting sources. By utilizing reverberation mapping analysis techniques, Kronos produces advanced maps of unprecedented resolution of the extreme environment in the inner cores of active galaxies. Similarly, Doppler tomography and eclipse mapping techniques characterize and map Galactic binary systems, revealing the details of the physics of accretion processes in black hole, neutron star, and white dwarf binary systems. The Kronos instrument complement, sensitivity, and orbital environment make it suitable to aggressively address time variable phenomena in a wide range of astronomical objects from nearby flare stars to distant galaxies.
Constraints on black hole remnants
Giddings, S.B. )
1994-01-15
One possible fate of information lost to black holes is its preservation in black hole remnants. It is argued that a type of effective field theory describes such remnants (generically referred to as informons). The general structure of such a theory is investigated and the infinite pair production problem is revisited. A toy model for remnants clarifies some of the basic issues; in particular, infinite remnant production is not suppressed simply by the large internal volumes as proposed in cornucopion scenarios. Criteria for avoiding infinite production are stated in terms of couplings in the effective theory. Such instabilities remain a problem barring what would be described in that theory as a strong coupling conspiracy. The relation to Euclidean calculations of cornucopion production is sketched, and potential flaws in that analysis are outlined. However, it is quite plausible that pair production of ordinary black holes (e.g., Reissner-Noerdstrom or others) is suppressed due to strong effective couplings. It also remains an open possibility that a microsopic dynamics can be found yielding an appropriate strongly coupled effective theory of neutral informons without infinite pair production.
Black hole binaries and microquasars
NASA Astrophysics Data System (ADS)
Zhang, Shuang-Nan
2013-12-01
This is a general review on the observations and physics of black hole X-ray binaries and microquasars, with the emphasize on recent developments in the high energy regime. The focus is put on understanding the accretion flows and measuring the parameters of black holes in them. It includes mainly two parts: i) Brief review of several recent review article on this subject; ii) Further development on several topics, including black hole spin measurements, hot accretion flows, corona formation, state transitions and thermal stability of standard think disk. This is thus not a regular bottom-up approach, which I feel not necessary at this stage. Major effort is made in making and incorporating from many sources useful plots and illustrations, in order to make this article more comprehensible to non-expert readers. In the end I attempt to make a unification scheme on the accretion-outflow (wind/jet) connections of all types of accreting BHs of all accretion rates and all BH mass scales, and finally provide a brief outlook.
NASA Astrophysics Data System (ADS)
Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew
2016-06-01
It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.
Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew
2016-06-10
It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.
Accretion disks around black holes
NASA Technical Reports Server (NTRS)
Abramowicz, M. A.
1994-01-01
The physics of accretion flow very close to a black hole is dominated by several general relativistic effects. It cannot be described by the standard Shakura Sunyaev model or by its relativistic version developed by Novikov and Thome. The most important of these effects is a dynamical mass loss from the inner edge of the disk (Roche lobe overflow). The relativistic Roche lobe overflow induces a strong advective cooling, which is sufficient to stabilize local, axially symmetric thermal and viscous modes. It also stabilizes the non-axially-symmetric global modes discovered by Papaloizou and Pringle. The Roche lobe overflow, however, destabilizes sufficiently self-gravitating accretion disks with respect to a catastrophic runaway of mass due to minute changes of the gravitational field induced by the changes in the mass and angular momentum of the central black hole. One of the two acoustic modes may become trapped near the inner edge of the disk. All these effects, absent in the standard model, have dramatic implications for time-dependent behavior of the accretion disks around black holes.
Black Holes, Worm Holes, and Future Space Propulsion
NASA Technical Reports Server (NTRS)
Barret, Chris
2000-01-01
NASA has begun examining the technologies needed for an Interstellar Mission. In 1998, a NASA Interstellar Mission Workshop was held at the California Institute of Technology to examine the technologies required. Since then, a spectrum of research efforts to support such a mission has been underway, including many advanced and futuristic space propulsion concepts which are being explored. The study of black holes and wormholes may provide some of the breakthrough physics needed to travel to the stars. The first black hole, CYGXI, was discovered in 1972 in the constellation Cygnus X-1. In 1993, a black hole was found in the center of our Milky Way Galaxy. In 1994, the black hole GRO J1655-40 was discovered by the NASA Marshall Space Flight center using the Gamma Ray Observatory. Today, we believe we have found evidence to support the existence of 19 black holes, but our universe may contain several thousands. This paper discusses the dead star states - - both stable and unstable, white dwarfs, neutron stars, pulsars, quasars, the basic features and types of black holes: nonspinning, nonspinning with charge, spinning, and Hawking's mini black holes. The search for black holes, gravitational waves, and Laser Interferometer Gravitational Wave Observatory (LIGO) are reviewed. Finally, concepts of black hole powered space vehicles and wormhole concepts for rapid interstellar travel are discussed in relation to the NASA Interstellar Mission.
Black Holes, Worm Holes, and Future Space Propulsion
NASA Technical Reports Server (NTRS)
Barret, Chris
2000-01-01
NASA has begun examining the technologies needed for an Interstellar Mission. In 1998, a NASA Interstellar Mission Workshop was held at the California Institute of Technology to examine the technologies required. Since then, a spectrum of research efforts to support such a mission has been underway, including many advanced and futuristic space propulsion concepts which are being explored. The study of black holes and wormholes may provide some of the breakthrough physics needed to travel to the stars. The first black hole, CYGXI, was discovered in 1972 in the constellation Cygnus X-1. In 1993, a black hole was found in the center of our Milky Way Galaxy. In 1994, the black hole GRO J1655-40 was discovered by the NASA Marshall Space Flight center using the Gamma Ray Observatory. Today, we believe we have found evidence to support the existence of 19 black holes, but our universe may contain several thousands. This paper discusses the dead star states - - both stable and unstable, white dwarfs, neutron stars, pulsars, quasars, the basic features and types of black holes: nonspinning, nonspinning with charge, spinning, and Hawking's mini black holes. The search for black holes, gravitational waves, and Laser Interferometer Gravitational Wave Observatory (LIGO) are reviewed. Finally, concepts of black hole powered space vehicles and wormhole concepts for rapid interstellar travel are discussed in relation to the NASA Interstellar Mission.
Charged spinning black holes as particle accelerators
Wei Shaowen; Liu Yuxiao; Guo Heng; Fu Chune
2010-11-15
It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy. In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole. The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin a but also on the charge Q of the black hole. We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin a of the extremal black hole satisfies (1/{radical}(3)){<=}(a/M){<=}1, where M is the mass of the Kerr-Newman black hole. The third condition implies that to obtain an arbitrarily high energy, the extremal Kerr-Newman black hole must have a large value of spin, which is a significant difference between the Kerr and Kerr-Newman black holes. Furthermore, we also show that, for a near-extremal black hole, there always exists a finite upper bound for center-of-mass energy, which decreases with the increase of the charge Q.
A Black Hole in Our Galactic Center
ERIC Educational Resources Information Center
Ruiz, Michael J.
2008-01-01
An introductory approach to black holes is presented along with astronomical observational data pertaining to the presence of a supermassive black hole at the center of our galaxy. Concepts of conservation of energy and Kepler's third law are employed so students can apply formulas from their physics class to determine the mass of the black hole…
A Black Hole in Our Galactic Center
ERIC Educational Resources Information Center
Ruiz, Michael J.
2008-01-01
An introductory approach to black holes is presented along with astronomical observational data pertaining to the presence of a supermassive black hole at the center of our galaxy. Concepts of conservation of energy and Kepler's third law are employed so students can apply formulas from their physics class to determine the mass of the black hole…
Stationary black holes: large D analysis
NASA Astrophysics Data System (ADS)
Suzuki, Ryotaku; Tanabe, Kentaro
2015-09-01
We consider the effective theory of large D stationary black holes. By solving the Einstein equations with a cosmological constant using the 1 /D expansion in near zone of the black hole we obtain the effective equation for the stationary black hole. The effective equation describes the Myers-Perry black hole, bumpy black holes and, possibly, the black ring solution as its solutions. In this effective theory the black hole is represented as an embedded membrane in the background, e.g., Minkowski or Anti-de Sitter spacetime and its mean curvature is given by the surface gravity redshifted by the background gravitational field and the local Lorentz boost. The local Lorentz boost property of the effective equation is observed also in the metric itself. In fact we show that the leading order metric of the Einstein equation in the 1 /D expansion is generically regarded as a Lorentz boosted Schwarzschild black hole. We apply this Lorentz boost property of the stationary black hole solution to solve perturbation equations. As a result we obtain an analytic formula for quasinormal modes of the singly rotating Myers-Perry black hole in the 1 /D expansion.
Hawking temperature of constant curvature black holes
Cai Ronggen; Myung, Yun Soo
2011-05-15
The constant curvature (CC) black holes are higher dimensional generalizations of Banados-Teitelboim-Zanelli black holes. It is known that these black holes have the unusual topology of M{sub D-1}xS{sup 1}, where D is the spacetime dimension and M{sub D-1} stands for a conformal Minkowski spacetime in D-1 dimensions. The unusual topology and time-dependence for the exterior of these black holes cause some difficulties to derive their thermodynamic quantities. In this work, by using a globally embedding approach, we obtain the Hawking temperature of the CC black holes. We find that the Hawking temperature takes the same form when using both the static and global coordinates. Also, it is identical to the Gibbons-Hawking temperature of the boundary de Sitter spaces of these CC black holes.
NASA's Chandra Finds Black Holes Are "Green"
NASA Astrophysics Data System (ADS)
2006-04-01
Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. The new Chandra finding shows that most of the energy released by matter falling toward a supermassive black hole is in the form of high-energy jets traveling at near the speed of light away from the black hole. This is an important step in understanding how such jets can be launched from magnetized disks of gas near the event horizon of a black hole. Illustration of Fuel for a Black Hole Engine Illustration of Fuel for a Black Hole Engine "Just as with cars, it's critical to know the fuel efficiency of black holes," said lead author Steve Allen of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, and the Stanford Linear Accelerator Center. "Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do." Allen and his team used Chandra to study nine supermassive black holes at the centers of elliptical galaxies. These black holes are relatively old and generate much less radiation than quasars, rapidly growing supermassive black holes seen in the early Universe. The surprise came when the Chandra results showed that these "quiet" black holes are all producing much more energy in jets of high-energy particles than in visible light or X-rays. These jets create huge bubbles, or cavities, in the hot gas in the galaxies. Animation of Black Hole in Elliptical Galaxy Animation of Black Hole in Elliptical Galaxy The efficiency of the black hole energy-production was calculated in two steps: first Chandra images of the inner regions of the galaxies were used to estimate how much fuel is available for the black hole; then Chandra images were used to estimate the power required to produce
Binary black hole merger dynamics and waveforms
NASA Technical Reports Server (NTRS)
Baker, John G.; Centrella, Joan; Choi, Dae-II; Koppitz, Michael; vanMeter, James
2006-01-01
We apply recently developed techniques for simulations of moving black holes to study dynamics and radiation generation in the last few orbits and merger of a binary black hole system. Our analysis produces a consistent picture from the gravitational wave forms and dynamical black hole trajectories for a set of simulations with black holes beginning on circular-orbit trajectories at a variety of initial separations. We find profound agreement at the level of 1% among the simulations for the last orbit, merger and ringdown, resulting in a final black hole with spin parameter a/m = 0.69. Consequently, we are confident that this part of our waveform result accurately represents the predictions from Einstein's General Relativity for the final burst of gravitational radiation resulting from the merger of an astrophysical system of equal-mass non-spinning black holes. We also find good agreement at a level of roughly 10% for the radiation generated in the preceding few orbits.
Boosting jet power in black hole spacetimes.
Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis
2011-08-02
The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.
Boosting jet power in black hole spacetimes
Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W.; Liebling, Steven L.; Motl, Patrick M.; Garrett, Travis
2011-01-01
The extraction of rotational energy from a spinning black hole via the Blandford–Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux. PMID:21768341
Tapping into the Energy of Black Holes
NASA Astrophysics Data System (ADS)
Motl, Patrick M.; Lenher, L.; Liebling, S.; Palenzuela, C.; Neilsen, D.; Hirschmann, E.
2012-01-01
The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.
Black holes in modified gravity (MOG)
NASA Astrophysics Data System (ADS)
Moffat, J. W.
2015-04-01
The field equations for scalar-tensor-vector gravity (STVG) or modified gravity (MOG) have a static, spherically symmetric black hole solution determined by the mass with two horizons. The strength of the gravitational constant is where is a parameter. A regular singularity-free MOG solution is derived using a nonlinear field dynamics for the repulsive gravitational field component and a reasonable physical energy-momentum tensor. The Kruskal-Szekeres completion of the MOG black hole solution is obtained. The Kerr-MOG black hole solution is determined by the mass , the parameter and the spin angular momentum . The equations of motion and the stability condition of a test particle orbiting the MOG black hole are derived, and the radius of the black hole photosphere and the shadows cast by the Schwarzschild-MOG and Kerr-MOG black holes are calculated. A traversable wormhole solution is constructed with a throat stabilized by the repulsive component of the gravitational field.
Escape of Black Holes from the Brane
NASA Astrophysics Data System (ADS)
Flachi, Antonino; Tanaka, Takahiro
2005-10-01
TeV-scale gravity theories allow the possibility of producing small black holes at energies that soon will be explored at the CERN LHC or at the Auger observatory. One of the expected signatures is the detection of Hawking radiation that might eventually terminate if the black hole, once perturbed, leaves the brane. Here, we study how the “black hole plus brane” system evolves once the black hole is given an initial velocity that mimics, for instance, the recoil due to the emission of a graviton. The results of our dynamical analysis show that the brane bends around the black hole, suggesting that the black hole eventually escapes into the extra dimensions once two portions of the brane come in contact and reconnect. This gives a dynamical mechanism for the creation of baby branes.
Black holes in the milky way galaxy.
Filippenko, A V
1999-08-31
Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4-16 times the mass of the sun, whereas the latter are "supermassive black holes" with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong.
Boson shells harboring charged black holes
Kleihaus, Burkhard; Kunz, Jutta; Laemmerzahl, Claus; List, Meike
2010-11-15
We consider boson shells in scalar electrodynamics coupled to Einstein gravity. The interior of the shells can be empty space, or harbor a black hole or a naked singularity. We analyze the properties of these types of solutions and determine their domains of existence. We investigate the energy conditions and present mass formulae for the composite black hole-boson shell systems. We demonstrate that these types of solutions violate black hole uniqueness.
Black holes and the chocolate cake concept.
Allen, A
1994-10-01
The force of black holes in the universe is compared with the intense gravitational fields that we must navigate in our personal galaxy. Stressed by the many demands of home, work, and community, we are in danger of slipping into the black holes present in every aspect of our lives. The Chocolate Cake Concept is offered as a means of avoiding the black holes by breaking down barriers that influence our attitudes.
Techniques for Binary Black Hole Simulations
NASA Technical Reports Server (NTRS)
Baker, John G.
2006-01-01
Recent advances in techniques for numerical simulation of black hole systems have enabled dramatic progress in astrophysical applications. Our approach to these simulations, which includes new gauge conditions for moving punctures, AMR, and specific tools for analyzing black hole simulations, has been applied to a variety of black hole configurations, typically resulting in simulations lasting several orbits. I will discuss these techniques, what we've learned in applications, and outline some areas for further development.
Spinning black holes as particle accelerators.
Jacobson, Ted; Sotiriou, Thomas P
2010-01-15
It has recently been pointed out that particles falling freely from rest at infinity outside a Kerr black hole can in principle collide with an arbitrarily high center of mass energy in the limiting case of maximal black hole spin. Here we aim to elucidate the mechanism for this fascinating result, and to point out its practical limitations, which imply that ultraenergetic collisions cannot occur near black holes in nature.
Corrected Entropy of BTZ Black Holes
NASA Astrophysics Data System (ADS)
Farahani, Hoda; Sadeghi, Jafar; Saadat, Hassan
2012-12-01
In this paper, corrected entropy of a class of BTZ black holes, include charge and rotation, studied. We obtain corrected Bekenstein-Hawking entropy and find that effect of charge viewed at order A -2, and effect of rotation viewed at order A -6, therefore Q and J don't have contribution in corrected entropy lower than the second order. We also write the first law of black hole thermodynamics for the case of charged rotating BTZ black hole.
Quantum radiation of general nonstationary black holes
NASA Astrophysics Data System (ADS)
Hua, Jia-Chen; Huang, Yong-Chang
2009-02-01
Quantum radiation of general nonstationary black holes is investigated by using the method of generalized tortoise-coordinate transformation (GTT). It is shown in general that the temperature and the shape of the event horizon of this kind of black holes depend on time and angle. Further, we find that the chemical potential in the thermal-radiation spectrum is equal to the highest energy of the negative-energy state of particles in nonthermal radiation for general nonstationary black holes.
Test fields cannot destroy extremal black holes
NASA Astrophysics Data System (ADS)
Natário, José; Queimada, Leonel; Vicente, Rodrigo
2016-09-01
We prove that (possibly charged) test fields satisfying the null energy condition at the event horizon cannot overspin/overcharge extremal Kerr-Newman or Kerr-Newman-anti de Sitter black holes, that is, the weak cosmic censorship conjecture cannot be violated in the test field approximation. The argument relies on black hole thermodynamics (without assuming cosmic censorship), and does not depend on the precise nature of the fields. We also discuss generalizations of this result to other extremal black holes.
Techniques for Binary Black Hole Simulations
NASA Technical Reports Server (NTRS)
Baker, John G.
2006-01-01
Recent advances in techniques for numerical simulation of black hole systems have enabled dramatic progress in astrophysical applications. Our approach to these simulations, which includes new gauge conditions for moving punctures, AMR, and specific tools for analyzing black hole simulations, has been applied to a variety of black hole configurations, typically resulting in simulations lasting several orbits. I will discuss these techniques, what we've learned in applications, and outline some areas for further development.
Causal Structures of Dynamic Black Holes
NASA Astrophysics Data System (ADS)
Brown, Beth A.; Lindesay, James
2010-10-01
Dynamic space-times, especially those manifesting horizons, provide useful laboratories for examining how macroscopic quantum behaviors consistently co-generate gravitational phenomena. For this reason, the behaviors and large-scale causal structures of spatially coherent dynamic black holes will be explored in this presentation. Geodesic motions on an evaporating black hole will also be presented. Research recently completed with Beth Brown, including her final Penrose diagram for an accreting black hole, will be presented.
Low-mass black holes as the remnants of primordial black hole formation.
Greene, Jenny E
2012-01-01
Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.
The Black Hole Formation Probability
NASA Astrophysics Data System (ADS)
Clausen, Drew R.; Piro, Anthony; Ott, Christian D.
2015-01-01
A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. Using the observed BH mass distribution from Galactic X-ray binaries, we investigate the probability that a star will make a BH as a function of its ZAMS mass. Although the shape of the black hole formation probability function is poorly constrained by current measurements, we believe that this framework is an important new step toward better understanding BH formation. We also consider some of the implications of this probability distribution, from its impact on the chemical enrichment from massive stars, to its connection with the structure of the core at the time of collapse, to the birth kicks that black holes receive. A probabilistic description of BH formation will be a useful input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.
Quantum capacity of quantum black holes
NASA Astrophysics Data System (ADS)
Adami, Chris; Bradler, Kamil
2014-03-01
The fate of quantum entanglement interacting with a black hole has been an enduring mystery, not the least because standard curved space field theory does not address the interaction of black holes with matter. We discuss an effective Hamiltonian of matter interacting with a black hole that has a precise analogue in quantum optics and correctly reproduces both spontaneous and stimulated Hawking radiation with grey-body factors. We calculate the quantum capacity of this channel in the limit of perfect absorption, as well as in the limit of a perfectly reflecting black hole (a white hole). We find that the white hole is an optimal quantum cloner, and is isomorphic to the Unruh channel with positive quantum capacity. The complementary channel (across the horizon) is entanglement-breaking with zero capacity, avoiding a violation of the quantum no-cloning theorem. The black hole channel on the contrary has vanishing capacity, while its complement has positive capacity instead. Thus, quantum states can be reconstructed faithfully behind the black hole horizon, but not outside. This work sheds new light on black hole complementarity because it shows that black holes can both reflect and absorb quantum states without violating the no-cloning theorem, and makes quantum firewalls obsolete.
Black Hole Researchers in Schools
NASA Astrophysics Data System (ADS)
Doran, Rosa
2016-07-01
"Black Holes in my School" is a research project that aims to explore the impact of engaging students in real research experiences while learning new skills and topics addressed in the regular school curriculum. The project introduces teachers to innovative tools for science teaching, explore student centered methodologies such as inquiry based learning and provides a setting where students take the role of an astrophysicist researching the field of compact stellar mass objects in binary systems. Students will study already existing data and use the Faulkes Telescopes to acquire new data. In this presentation the main aim is to present the framework being built and the results achieved so far.
Distinguishability of black hole microstates
NASA Astrophysics Data System (ADS)
Bao, Ning; Ooguri, Hirosi
2017-09-01
We use the Holevo information to estimate distinguishability of microstates of a black hole in anti-de Sitter space by measurements one can perform on a subregion of a Cauchy surface of the dual conformal field theory. We find that microstates are not distinguishable at all until the subregion reaches a certain size and that perfect distinguishability can be achieved before the subregion covers the entire Cauchy surface. We will compare our results with expectations from the entanglement wedge reconstruction, tensor network models, and the bit threads interpretation of the Ryu-Takayanagi formula.
Corda, Christian
2015-03-10
The idea that black holes (BHs) result in highly excited states representing both the “hydrogen atom” and the “quasi-thermal emission” in quantum gravity is today an intuitive but general conviction. In this paper it will be shown that such an intuitive picture is more than a picture. In fact, we will discuss a model of quantum BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. The model is completely consistent with existing results in the literature, starting from the celebrated result of Bekenstein on the area quantization.
Comments on black holes in bubbling spacetimes
NASA Astrophysics Data System (ADS)
Horowitz, Gary T.; Kunduri, Hari K.; Lucietti, James
2017-06-01
In five-dimensional minimal supergravity, there are spherical black holes with nontrivial topology outside the horizon which have the same conserved charges at infinity as the BMPV solution. We show that some of these black holes have greater entropy than the BMPV solution. These spacetimes are all asymptotically flat, stationary, and supersymmetric. We also show that there is a limit in which the black hole shrinks to zero size and the solution becomes a nonsingular "bubbling" geometry. Thus, these solutions provide explicit analytic examples of placing black holes inside solitons.
Micro black holes and the democratic transition
NASA Astrophysics Data System (ADS)
Dvali, Gia; Pujolàs, Oriol
2009-03-01
Unitarity implies that the evaporation of microscopic quasiclassical black holes cannot be universal in different particle species. This creates a puzzle, since it conflicts with the thermal nature of quasiclassical black holes, according to which all of the species should see the same horizon and be produced with the same Hawking temperatures. We resolve this puzzle by showing that for the microscopic black holes, on top of the usual quantum evaporation time, there is a new time scale which characterizes a purely classical process during which the black hole loses the ability to differentiate among the species and becomes democratic. We demonstrate this phenomenon in a well-understood framework of large extra dimensions, with a number of parallel branes. An initially nondemocratic black hole is the one localized on one of the branes, with its high-dimensional Schwarzschild radius being much shorter than the interbrane distance. Such a black hole seemingly cannot evaporate into the species localized on the other branes that are beyond its reach. We demonstrate that in reality the system evolves classically in time, in such a way that the black hole accretes the neighboring branes. The end result is a completely democratic static configuration, in which all of the branes share the same black hole and all of the species are produced with the same Hawking temperature. Thus, just like their macroscopic counterparts, the microscopic black holes are universal bridges to the hidden sector physics.
Black hole collapse and democratic models
NASA Astrophysics Data System (ADS)
Jansen, Aron; Magán, Javier M.
2016-11-01
We study the evolution of black hole entropy and temperature in collapse scenarios in asymptotically anti-de Sitter spacetime, finding three generic lessons. First, entropy evolution is extensive. Second, at large times, entropy and temperature ring with twice the frequency of the lowest quasinormal mode. Third, the entropy oscillations saturate black hole area theorems in general relativity. The first two features are characteristic of entanglement dynamics in "democratic" models. Solely based on general relativity and the Bekenstein-Hawking entropy formula, our results point to democratic models as microscopic theories of black holes. The third feature can be taken as a prediction for microscopic models of black hole physics.
Semiclassical geometry of charged black holes
Frolov, Andrei V.; Kristjansson, Kristjan R.; Thorlacius, Larus
2005-07-15
At the classical level, two-dimensional dilaton gravity coupled to an abelian gauge field has charged black hole solutions, which have much in common with four-dimensional Reissner-Nordstroem black holes, including multiple asymptotic regions, timelike curvature singularities, and Cauchy horizons. The black hole spacetime is, however, significantly modified by quantum effects, which can be systematically studied in this two-dimensional context. In particular, the back-reaction on the geometry due to pair-creation of charged fermions destabilizes the inner horizon and replaces it with a spacelike curvature singularity. The semiclassical geometry has the same global topology as an electrically neutral black hole.
Foundations of multiple-black-hole evolutions
Lousto, Carlos O.; Zlochower, Yosef
2008-01-15
We present techniques for long-term, stable, and accurate evolutions of multiple-black-hole spacetimes using the 'moving puncture' approach with fourth- and eighth-order finite-difference stencils. We use these techniques to explore configurations of three black holes in a hierarchical system consisting of a third black hole approaching a quasicircular black-hole binary, and find that, depending on the size of the binary, the resulting encounter may lead to a prompt merger of all three black holes, production of a highly elliptical binary (with the third black hole remaining unbound), or disruption of the binary (leading to three free black holes). We also analyze the classical Burrau three-body problem using full numerical evolutions. In both cases, we find behaviors distinctly different from Newtonian predictions, which has important implications for N-body black-hole simulations. For our simulations we use approximate analytic initial data. We find that the eighth-order stencils significantly reduce the numerical errors for our choice of grid sizes, and that the approximate initial data produces the expected waveforms for black-hole binaries with modest initial separations.
Do black holes really evaporate thermally
NASA Astrophysics Data System (ADS)
Tipler, F. J.
1980-09-01
The Raychaudhuri equation is used to analyze the effect of the Hawking radiation back reaction upon a black-hole event horizon. It is found that if the effective stress-energy tensor of the Hawking radiation has negative energy density as expected, then an evaporating black hole initially a solar mass in size must disappear in less than a second. This implies that either the evaporation process, if it occurs at all, must be quite different from what is commonly supposed, or else black-hole event horizons - and hence black holes - do not exist.
Black holes and local dark matter
NASA Technical Reports Server (NTRS)
Hegyi, D. J.; Kolb, E. W.; Olive, K. A.
1986-01-01
Two independent constraints are placed on the amount of dark matter in black holes contained in the galactic disk. First, gas accretion by black holes leads to X-ray emission which cannot exceed the observed soft X-ray background. Second, metals produced in stellar processes that lead to black hole formation cannot exceed the observed disk metal abundance. Based on these constraints, it appears unlikely that the missing disk mass could be contained in black holes. A consequence of this conclusion is that at least two different types of dark matter are needed to solve the various missing mass problems.
Black hole evaporation in conformal gravity
NASA Astrophysics Data System (ADS)
Bambi, Cosimo; Modesto, Leonardo; Porey, Shiladitya; Rachwał, Lesław
2017-09-01
We study the formation and the evaporation of a spherically symmetric black hole in conformal gravity. From the collapse of a spherically symmetric thin shell of radiation, we find a singularity-free non-rotating black hole. This black hole has the same Hawking temperature as a Schwarzschild black hole with the same mass, and it completely evaporates either in a finite or in an infinite time, depending on the ensemble. We consider the analysis both in the canonical and in the micro-canonical statistical ensembles. Last, we discuss the corresponding Penrose diagram of this physical process.
Black Holes versus Supersymmetry at the LHC
NASA Astrophysics Data System (ADS)
Roy, Arunava; Cavaglia, Marco
2007-11-01
Supersymmetry and extra dimensions are the two most promising candidates for new physics at the TeV scale. Supersymmetric particles or extra-dimensional effects could soon be observed at the Large Hadron Collider. In this paper we assess the distinguishability of supersymmetry and black hole events at the LHC. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET, the latter providing the mass spectrum. Our analysis shows that supersymmetry and black hole events at the Large Hadron Collider can be easily discriminated.
On black hole spectroscopy via adiabatic invariance
NASA Astrophysics Data System (ADS)
Jiang, Qing-Quan; Han, Yan
2012-12-01
In this Letter, we obtain the black hole spectroscopy by combining the black hole property of adiabaticity and the oscillating velocity of the black hole horizon. This velocity is obtained in the tunneling framework. In particular, we declare, if requiring canonical invariance, the adiabatic invariant quantity should be of the covariant form Iadia = ∮pi dqi. Using it, the horizon area of a Schwarzschild black hole is quantized independently of the choice of coordinates, with an equally spaced spectroscopy always given by ΔA = 8 π lp2 in the Schwarzschild and Painlevé coordinates.
Schwarzschild black holes can wear scalar wigs.
Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2012-08-24
We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.
Particle accelerators inside spinning black holes.
Lake, Kayll
2010-05-28
On the basis of the Kerr metric as a model for a spinning black hole accreting test particles from rest at infinity, I show that the center-of-mass energy for a pair of colliding particles is generically divergent at the inner horizon. This shows not only that classical black holes are internally unstable, but also that Planck-scale physics is a characteristic feature within black holes at scales much larger that the Planck length. The novel feature of the divergence discussed here is that the phenomenon is present only for black holes with rotation, and in this sense it is distinct from the well-known Cauchy horizon instability.
Rotating black holes and Coriolis effect
NASA Astrophysics Data System (ADS)
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.
Gamma ray astronomy and black hole astrophysics
NASA Technical Reports Server (NTRS)
Liang, Edison P.
1990-01-01
The study of soft gamma emissions from black-hole candidates is identified as an important element in understanding black-hole phenomena ranging from stellar-mass black holes to AGNs. The spectra of Cyg X-1 and observations of the Galactic Center are emphasized, since thermal origins and MeV gamma-ray bumps are evident and suggest a thermal-pair cloud picture. MeV gamma-ray observations are suggested for studying black hole astrophysics such as the theorized escaping pair wind, the anticorrelation between the MeV gamma bump and the soft continuum, and the relationship between source compactness and temperature.
NASA Observatory Confirms Black Hole Limits
NASA Astrophysics Data System (ADS)
2005-02-01
The very largest black holes reach a certain point and then grow no more, according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists have also discovered many previously hidden black holes that are well below their weight limit. These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the Sun, ate voraciously during the early Universe. Nearly all of them ran out of 'food' billions of years ago and went onto a forced starvation diet. Focus on Black Holes in the Chandra Deep Field North Focus on Black Holes in the Chandra Deep Field North On the other hand, black holes between about 10 and 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing today. "Our data show that some supermassive black holes seem to binge, while others prefer to graze", said Amy Barger of the University of Wisconsin in Madison and the University of Hawaii, lead author of the paper describing the results in the latest issue of The Astronomical Journal (Feb 2005). "We now understand better than ever before how supermassive black holes grow." One revelation is that there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies, but didn't know as much about the black holes at their centers. DSS Optical Image of Lockman Hole DSS Optical Image of Lockman Hole "These galaxies lose material into their central black holes at the same time that they make their stars," said Barger. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers have made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer by. Now, for the first
Primordial black holes in globular clusters
NASA Technical Reports Server (NTRS)
Sigurdsson, Steinn; Hernquist, Lars
1993-01-01
It has recently been recognized that significant numbers of medium-mass back holes (of order 10 solar masses) should form in globular clusters during the early stages of their evolution. Here we explore the dynamical and observational consequences of the presence of such a primordial black-hole population in a globular cluster. The holes initially segregate to the cluster cores, where they form binary and multiple black-hole systems. The subsequent dynamical evolution of the black-hole population ejects most of the holes on a relatively short timescale: a typical cluster will retain between zero and four black holes in its core, and possibly a few black holes in its halo. The presence of binary, triple, and quadruple black-hole systems in cluster cores will disrupt main-sequence and giant stellar binaries; this may account for the observed anomalies in the distribution of binaries in globular clusters. Furthermore, tidal interactions between a multiple black-hole system and a red giant star can remove much of the red giant's stellar envelope, which may explain the puzzling absence of larger red giants in the cores of some very dense clusters.
Primordial black holes in globular clusters
NASA Technical Reports Server (NTRS)
Sigurdsson, Steinn; Hernquist, Lars
1993-01-01
It has recently been recognized that significant numbers of medium-mass back holes (of order 10 solar masses) should form in globular clusters during the early stages of their evolution. Here we explore the dynamical and observational consequences of the presence of such a primordial black-hole population in a globular cluster. The holes initially segregate to the cluster cores, where they form binary and multiple black-hole systems. The subsequent dynamical evolution of the black-hole population ejects most of the holes on a relatively short timescale: a typical cluster will retain between zero and four black holes in its core, and possibly a few black holes in its halo. The presence of binary, triple, and quadruple black-hole systems in cluster cores will disrupt main-sequence and giant stellar binaries; this may account for the observed anomalies in the distribution of binaries in globular clusters. Furthermore, tidal interactions between a multiple black-hole system and a red giant star can remove much of the red giant's stellar envelope, which may explain the puzzling absence of larger red giants in the cores of some very dense clusters.
Entanglement Entropy of Black Holes
NASA Astrophysics Data System (ADS)
Solodukhin, Sergey N.
2011-12-01
The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as ’t Hooft’s brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the blackhole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.
Codimension-2 Brane Black Holes
NASA Astrophysics Data System (ADS)
Zamorano, Nelson; Arias, Cesar; Ordenes, Ariel; Guzman, Francisco
2012-03-01
We analyze the geometry associated to a six dimensional solution of the Einstein's equations. It describes a Schwarzschild de-Sitter black hole on a 3-brane, surrounded by a two dimensional compact bulk. A four dimensional effective cosmological constant and a Planck mass are matched to their six dimensional counterpart. Deviation from Newton's law are computed in both of the solutions found. To learn about the geometry of the bulk, we study the geodesics in this sector. At least, in our opinion, there are some features of these solutions that makes worth to pursue this analysis. The singularity associated to the warped bulk is controlled by the mass M of the black hole. It vanishes if we set M=0. In the same context, it makes an interesting problem to study the Gregory-Laflamme instability in this context [1]. Another feature is the rugby ball type of geometry exhibited by these solutions [2]. They end up in two conical singularities at its respective poles. The branes are located precisely at the poles. Besides, a Wick's rotation generates a connection between different solutions. [4pt] [1] R. Gregory and R. Laflamme, Phys. Rev Lett., 70,2837 (1993)[0pt] [2] S. M. Carroll and M. M. Guica, arXiv:hep-th/0302067
Superluminality, black holes and EFT
NASA Astrophysics Data System (ADS)
Goon, Garrett; Hinterbichler, Kurt
2017-02-01
Under the assumption that a UV theory does not display superluminal behavior, we ask what constraints on superluminality are satisfied in the effective field theory (EFT). We study two examples of effective theories: quantum electrodynamics (QED) coupled to gravity after the electron is integrated out, and the flat-space galileon. The first is realized in nature, the second is more speculative, but they both exhibit apparent superluminality around non-trivial backgrounds. In the QED case, we attempt, and fail, to find backgrounds for which the superluminal signal advance can be made larger than the putative resolving power of the EFT. In contrast, in the galileon case it is easy to find such backgrounds, indicating that if the UV completion of the galileon is (sub)luminal, quantum corrections must become important at distance scales of order the Vainshtein radius of the background configuration, much larger than the naive EFT strong coupling distance scale. Such corrections would be reminiscent of the non-perturbative Schwarzschild scale quantum effects that are expected to resolve the black hole information problem. Finally, a byproduct of our analysis is a calculation of how perturbative quantum effects alter charged Reissner-Nordstrom black holes.
Spacetime and orbits of bumpy black holes
Vigeland, Sarah J.; Hughes, Scott A.
2010-01-15
Our Universe contains a great number of extremely compact and massive objects which are generally accepted to be black holes. Precise observations of orbital motion near candidate black holes have the potential to determine if they have the spacetime structure that general relativity demands. As a means of formulating measurements to test the black hole nature of these objects, Collins and Hughes introduced ''bumpy black holes'': objects that are almost, but not quite, general relativity's black holes. The spacetimes of these objects have multipoles that deviate slightly from the black hole solution, reducing to black holes when the deviation is zero. In this paper, we extend this work in two ways. First, we show how to introduce bumps which are smoother and lead to better behaved orbits than those in the original presentation. Second, we show how to make bumpy Kerr black holes--objects which reduce to the Kerr solution when the deviation goes to zero. This greatly extends the astrophysical applicability of bumpy black holes. Using Hamilton-Jacobi techniques, we show how a spacetime's bumps are imprinted on orbital frequencies, and thus can be determined by measurements which coherently track the orbital phase of a small orbiting body. We find that in the weak field, orbits of bumpy black holes are modified exactly as expected from a Newtonian analysis of a body with a prescribed multipolar structure, reproducing well-known results from the celestial mechanics literature. The impact of bumps on strong-field orbits is many times greater than would be predicted from a Newtonian analysis, suggesting that this framework will allow observations to set robust limits on the extent to which a spacetime's multipoles deviate from the black hole expectation.
Are LIGO's Black Holes Made from Smaller Black Holes?
NASA Astrophysics Data System (ADS)
Fishbach, Maya; Holz, Daniel E.; Farr, Ben
2017-05-01
One proposed formation channel for stellar mass black holes (BHs) is through hierarchical mergers of smaller BHs. Repeated mergers between comparable mass BHs leave an imprint on the spin of the resulting BH since the final BH spin is largely determined by the orbital angular momentum of the binary. We find that for stellar mass BHs forming hierarchically the distribution of spin magnitudes is universal, with a peak at a˜ 0.7 and little support below a˜ 0.5. We show that the spin distribution is robust against changes to the mass ratio of the merging binaries, the initial spin distribution of the first generation of BHs, and the number of merger generations. While we assume an isotropic distribution of initial spin directions, spins that are preferentially aligned or antialigned do not qualitatively change our results. We also consider a “cluster catastrophe” model for BH formation in which we allow for mergers of arbitrary mass ratios and show that this scenario predicts a unique spin distribution that is similar to the universal distribution derived for major majors. We explore the ability of spin measurements from ground-based gravitational-wave (GW) detectors to constrain hierarchical merger scenarios. We apply a hierarchical Bayesian mixture model to mock GW data and argue that the fraction of BHs that formed through hierarchical mergers will be constrained with { O }(100) LIGO binary black hole detections, while with { O }(10) detections we could falsify a model in which all component BHs form hierarchically.
Black Hole Interior in Quantum Gravity.
Nomura, Yasunori; Sanches, Fabio; Weinberg, Sean J
2015-05-22
We discuss the interior of a black hole in quantum gravity, in which black holes form and evaporate unitarily. The interior spacetime appears in the sense of complementarity because of special features revealed by the microscopic degrees of freedom when viewed from a semiclassical standpoint. The relation between quantum mechanics and the equivalence principle is subtle, but they are still consistent.
How to Create Black Holes on Earth
ERIC Educational Resources Information Center
Bleicher, Marcus
2007-01-01
We present a short overview on the ideas of large extra dimensions and their implications for the possible production of micro black holes in the next generation particle accelerator at CERN (Geneva, Switzerland) from this year on. In fact, the possibility of black hole production on Earth is currently one of the most exciting predictions for the…
Physics near Rapidly Spinning Black Holes
NASA Astrophysics Data System (ADS)
Gralla, Samuel; Lupsasca, Alexandru; Hughes, Scott; Porfyriadis, Achilleas; Strominger, Andrew; Warburton, Niels
2016-03-01
The near-horizon region of a near-extreme Kerr black hole possesses additional emergent symmetries and can be thought of as a spacetime in its own right. I will discuss the dynamics of particles and fields in this region, the constraints imposed by symmetry, and observational consequences for astrophysical black holes.
Quantum corrections and extremal black holes
NASA Astrophysics Data System (ADS)
Alejandro, G.; Mazzitelli, F. D.; Núñez, C.
1995-02-01
We consider static solutions of two dimensional dilaton gravity models as toy laboratories to address the question of the final fate of black holes. A nonperturbative correction to the CGHS potential term is shown to lead classically to an extremal black hole geometry, thus providing a plausible solution to the Hawking evaporation paradox. However, the full quantum theory does not admit an extremal solution.
How to Create Black Holes on Earth
ERIC Educational Resources Information Center
Bleicher, Marcus
2007-01-01
We present a short overview on the ideas of large extra dimensions and their implications for the possible production of micro black holes in the next generation particle accelerator at CERN (Geneva, Switzerland) from this year on. In fact, the possibility of black hole production on Earth is currently one of the most exciting predictions for the…
Slender Galaxy with Robust Black Hole
NASA Technical Reports Server (NTRS)
2008-01-01
This plot of data from NASA's Spitzer Space Telescope indicates that a flat, spiral galaxy called NGC 3621 has a feeding, supermassive black hole lurking within it -- a surprise considering that astronomers thought this particular class of super-thin galaxies lacked big black holes.
The data were captured by Spitzer's infrared spectrograph, an instrument that cracks infrared light open to reveal the signatures of elements. In this case, the data, or spectrum, for NGC 3621, shows the signature of highly ionized neon -- a sure sign of an active, supermassive black hole. Only a black hole that is actively consuming gas and stars has enough energy to ionize neon to this state. The other features in this plot are polycyclic aromatic hydrocarbons and chlorine, produced in the gas surrounding stars.
The results challenge current theories, which hold that supermassive black holes require the bulbous central bulges that poke out from many spiral galaxies to form and grow. NGC 3621 is the second disk galaxy without any bulge found to harbor a supermassive black hole; the first, found in 2003, is NGC 4395. Astronomers have also used Spitzer to find six other mega black holes in thin spirals with only minimal bulges. Together, the findings indicate that, for a galaxy, being plump in the middle is not a necessary condition for growing a rotund black hole.
Gravitational Waves From Supermassive Black Holes
NASA Astrophysics Data System (ADS)
di Girolamo, Tristano
2016-10-01
In this talk, I will present the first direct detections of gravitational waves from binary stellar-mass black hole mergers during the first observing run of the two detectors of the Advanced Laser Interferometer Gravitational-wave Observatory, which opened the field of gravitational-wave astronomy, and then discuss prospects for observing gravitational waves from supermassive black holes with future detectors.
Slender Galaxy with Robust Black Hole
NASA Technical Reports Server (NTRS)
2008-01-01
This plot of data from NASA's Spitzer Space Telescope indicates that a flat, spiral galaxy called NGC 3621 has a feeding, supermassive black hole lurking within it -- a surprise considering that astronomers thought this particular class of super-thin galaxies lacked big black holes.
The data were captured by Spitzer's infrared spectrograph, an instrument that cracks infrared light open to reveal the signatures of elements. In this case, the data, or spectrum, for NGC 3621, shows the signature of highly ionized neon -- a sure sign of an active, supermassive black hole. Only a black hole that is actively consuming gas and stars has enough energy to ionize neon to this state. The other features in this plot are polycyclic aromatic hydrocarbons and chlorine, produced in the gas surrounding stars.
The results challenge current theories, which hold that supermassive black holes require the bulbous central bulges that poke out from many spiral galaxies to form and grow. NGC 3621 is the second disk galaxy without any bulge found to harbor a supermassive black hole; the first, found in 2003, is NGC 4395. Astronomers have also used Spitzer to find six other mega black holes in thin spirals with only minimal bulges. Together, the findings indicate that, for a galaxy, being plump in the middle is not a necessary condition for growing a rotund black hole.
Effective Potential in Noncommutative BTZ Black Hole
NASA Astrophysics Data System (ADS)
Sadeghi, Jafar; Shajiee, Vahid Reza
2016-02-01
In this paper, we investigated the noncommutative rotating BTZ black hole and showed that such a space-time is not maximally symmetric. We calculated effective potential for the massive and the massless test particle by geodesic equations, also we showed effect of non-commutativity on the minimum mass of BTZ black hole.
Pregalactic black holes - A new constraint
NASA Technical Reports Server (NTRS)
Barrow, J. D.; Silk, J.
1979-01-01
Pregalactic black holes accrete matter in the early universe and produce copious amounts of X radiation. By using observations of the background radiation in the X and gamma wavebands, a strong constraint is imposed upon their possible abundance. If pregalactic black holes are actually present, several outstanding problems of cosmogony can be resolved with typical pregalactic black hole masses of 100 solar masses. Significantly more massive holes cannot constitute an appreciable mass fraction of the universe and are limited by a specific mass-density bound.
Black holes: Supersymmetry and the information paradox
NASA Astrophysics Data System (ADS)
Peet, Amanda Wensley
1994-01-01
U(1) times U(1) asymptotically flat dilaton black holes are investigated in the context of N = 4, d = 4 supergravity, or dimensionally reduced superstring theory. It is found that extremal (multi-) black holes are supersymmetric, and that the supersymmetric positivity bounds on the black hole mass coincide with the bounds coming from cosmic censorship. Temperature, entropy and horizon properties are discussed in connection with the extremal limit. The on-shell action is given and for extremal black holes is argued to be unaltered by higher-order quantum corrections in the supersymmetric theory. The entropy is related to the Euclidean action via the Gibbons-Hawking method, is found to be one-quarter of the horizon area, and vanishes for maximally supersymmetric black holes. Lastly, the near-horizon behavior of extremal black holes is investigated. N = 1 supersymmetric black holes are found to tend to a Robinson-Bertotti-type geometry with doubling of supersymmetries; no such doubling is found for the N = 2 case. Topics relevant to the Information Paradox of black hole physics are investigated. First, prime-t Hooft's S-matrix approach to the puzzles of black hole evaporation is clarified by considering d = 1 + 1 electrodynamic in a linear dilaton background; analogues of black holes, Hawking evaporation, and an information paradox exist in this system. The paradox is resolved in the full quantum theory where the exact S-matrix is calculated. Secondly, a study of tachyon hair on black holes in two-dimensional string theory is presented. Such black holes if static can have tachyon hair; configurations nonsingular at the horizon have nonvanishing asymptotic energy density. There also exist static solutions with finite total energy and singular horizon. Dynamical arguments suggest that neither type of tachyon hair will be present on a black hole formed in gravitational collapse. Lastly, thermalization of a (fundamental) string falling toward the horizon of a four
FEASTING BLACK HOLE BLOWS BUBBLES
NASA Technical Reports Server (NTRS)
2002-01-01
A monstrous black hole's rude table manners include blowing huge bubbles of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this bubble-blowing phase is a short-lived event. The bubble is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter bubble is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the bubbles. The red regions in the picture denote the hot gas
FEASTING BLACK HOLE BLOWS BUBBLES
NASA Technical Reports Server (NTRS)
2002-01-01
A monstrous black hole's rude table manners include blowing huge bubbles of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this bubble-blowing phase is a short-lived event. The bubble is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter bubble is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the bubbles. The red regions in the picture denote the hot gas
Black hole thermodynamics in MOdified Gravity (MOG)
NASA Astrophysics Data System (ADS)
Mureika, Jonas R.; Moffat, John W.; Faizal, Mir
2016-06-01
We analyze the thermodynamical properties of black holes in a modified theory of gravity, which was initially proposed to obtain correct dynamics of galaxies and galaxy clusters without dark matter. The thermodynamics of non-rotating and rotating black hole solutions resembles similar solutions in Einstein-Maxwell theory with the electric charge being replaced by a new mass dependent gravitational charge Q =√{ αGN } M. This new mass dependent charge modifies the effective Newtonian constant from GN to G =GN (1 + α), and this in turn critically affects the thermodynamics of the black holes. We also investigate the thermodynamics of regular solutions, and explore the limiting case when no horizons forms. So, it is possible that the modified gravity can lead to the absence of black hole horizons in our universe. Finally, we analyze corrections to the thermodynamics of a non-rotating black hole and obtain the usual logarithmic correction term.
Testing conformal gravity with astrophysical black holes
NASA Astrophysics Data System (ADS)
Bambi, Cosimo; Cao, Zheng; Modesto, Leonardo
2017-03-01
Weyl conformal symmetry can solve the problem the spacetime singularities present in Einstein's gravity. In a recent paper, two of us have found a singularity-free rotating black hole solution in conformal gravity. In addition to the mass M and the spin angular momentum J of the black hole, the new solution has a new parameter, L , which here we consider to be proportional to the black hole mass. Since the solution is conformally equivalent to the Kerr metric, photon trajectories are unchanged, while the structure of an accretion disk around a black hole is affected by the value of the parameter L . In this paper, we show that x-ray data of astrophysical black holes require L /M <1.2 .
Renormalized vacuum polarization of rotating black holes
NASA Astrophysics Data System (ADS)
Ferreira, Hugo R. C.
2015-04-01
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, for a given quantum state, on a rotating black hole, such as the physically relevant case of the Kerr black hole in four dimensions.
Central charge for the Schwarzschild black hole
NASA Astrophysics Data System (ADS)
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.
Thermodynamics in Black-Hole Correspondence
NASA Astrophysics Data System (ADS)
Chen, Bin; Zhang, Jia-Ju
2013-09-01
The area law of Bekenstein-Hawking entropy of the black hole suggests that the black hole should have a lower-dimensional holographic description. It has been found recently that a large class of rotating and charged black holes could be holographically described a two-dimensional (2D) conformal field theory (CFT). We show that the universal information of the dual CFT, including the central charges and the temperatures, is fully encoded in the thermodynamics laws of both outer and inner horizons. These laws, characterizing how the black hole responds under the perturbation, allows us to read different dual pictures with respect to different kinds of perturbations. The remarkable effectiveness of this thermodynamics method suggest that the inner horizon could play a key role in the study of holographic description of the black hole.
Unveiling early black holes with JWST
NASA Astrophysics Data System (ADS)
Natarajan, Priyamvada
The formation of direct collapse black hole seeds with masses ~104 - 105 ~M⊙ could help explain the assembly of supermassive black holes powering high redshift quasars. Conditions conducive to the formation of these massive initial seeds exist at high redshift. Halos hosting these massive seeds merge promptly with a nearby galaxy. These early stage mergers at high redshift produce a new class of transient galaxies that contain an accreting black hole that is over-massive compared to the newly acquired stellar component - Obese Black hole Galaxies (OBGs). During this phase, the accretion luminosity of the direct collapse black hole seed exceeds that of the acquired stellar component. Here we calculate the multi-wavelength spectrum of this short-lived OBG stage, and show that there exist unique observational signatures in long wavelengths spanning near, mid to far-infrared that should be detectable by instruments aboard the upcoming James Webb Space Telescope (JWST).
Modeling Flows Around Merging Black Hole Binaries
NASA Technical Reports Server (NTRS)
Centrella, Joan
2008-01-01
Coalescing massive black hole binaries are produced by the merger of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases in which the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a first step towards this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We report on the results of these initial simulations and discuss their likely importance for future hydrodynamical simulations.
No supermassive black hole in M33?
Merritt, D; Ferrarese, L; Joseph, C L
2001-08-10
We observed the nucleus of M33, the third-brightest galaxy in the Local Group, with the Space Telescope Imaging Spectrograph at a resolution at least a factor of 10 higher than previously obtained. Rather than the steep rise expected within the radius of gravitational influence of a supermassive black hole, the random stellar velocities showed a decrease within a parsec of the center of the galaxy. The implied upper limit on the mass of the central black hole is only 3000 solar masses, about three orders of magnitude lower than the dynamically inferred mass of any other supermassive black hole. Detecting black holes of only a few thousand solar masses is observationally challenging, but it is critical to establish how supermassive black holes relate to their host galaxies, and which mechanisms influence the formation and evolution of both.
Supermassive Black Holes and Galaxy Evolution
NASA Technical Reports Server (NTRS)
Merritt, D.
2004-01-01
Supermassive black holes appear to be generic components of galactic nuclei. The formation and growth of black holes is intimately connected with the evolution of galaxies on a wide range of scales. For instance, mergers between galaxies containing nuclear black holes would produce supermassive binaries which eventually coalesce via the emission of gravitational radiation. The formation and decay of these binaries is expected to produce a number of observable signatures in the stellar distribution. Black holes can also affect the large-scale structure of galaxies by perturbing the orbits of stars that pass through the nucleus. Large-scale N-body simulations are beginning to generate testable predictions about these processes which will allow us to draw inferences about the formation history of supermassive black holes.
Shadow of noncommutative geometry inspired black hole
Wei, Shao-Wen; Cheng, Peng; Zhong, Yi; Zhou, Xiang-Nan E-mail: pcheng14@lzu.edu.cn E-mail: zhouxn10@lzu.edu.cn
2015-08-01
In this paper, the shadow casted by the rotating black hole inspired by noncommutative geometry is investigated. In addition to the dimensionless spin parameter a/M{sub 0} with M{sub 0} black hole mass and inclination angle i, the dimensionless noncommutative parameter √θ/M{sub 0} is also found to affect the shape of the black hole shadow. The result shows that the size of the shadow slightly decreases with the parameter √θ/M{sub 0}, while the distortion increases with it. Compared to the Kerr black hole, the parameter √θ/M{sub 0} increases the deformation of the shadow. This may offer a way to distinguish noncommutative geometry inspired black hole from Kerr one via astronomical instruments in the near future.
Binary Black Holes from Dense Star Clusters
NASA Astrophysics Data System (ADS)
Rodriguez, Carl
2017-01-01
The recent detections of gravitational waves from merging binary black holes have the potential to revolutionize our understanding of compact object astrophysics. But to fully utilize this new window into the universe, we must compare these observations to detailed models of binary black hole formation throughout cosmic time. In this talk, I will review our current understanding of cluster dynamics, describing how binary black holes can be formed through gravitational interactions in dense stellar environments, such as globular clusters and galactic nuclei. I will review the properties and merger rates of binary black holes from the dynamical formation channel. Finally, I will describe how the spins of a binary black hole are determined by its formation history, and how we can use this to discriminate between dynamically-formed binaries and those formed from isolated evolution in galactic fields.
Modeling Flows Around Merging Black Hole Binaries
NASA Technical Reports Server (NTRS)
Centrella, Joan
2008-01-01
Coalescing massive black hole binaries are produced by the merger of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases in which the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a first step towards this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We report on the results of these initial simulations and discuss their likely importance for future hydrodynamical simulations.
Magnetized black holes and nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Kruglov, S. I.
2017-08-01
A new model of nonlinear electrodynamics with two parameters is proposed. We study the phenomenon of vacuum birefringence, the causality and unitarity in this model. There is no singularity of the electric field in the center of pointlike charges and the total electrostatic energy is finite. We obtain corrections to the Coulomb law at r →∞. The weak, dominant and strong energy conditions are investigated. Magnetized charged black hole is considered and we evaluate the mass, metric function and their asymptotic at r →∞ and r → 0. The magnetic mass of the black hole is calculated. The thermodynamic properties and thermal stability of regular black holes are discussed. We calculate the Hawking temperature of black holes and show that there are first-order and second-order phase transitions. The parameters of the model when the black hole is stable are found.
Dual jets from binary black holes.
Palenzuela, Carlos; Lehner, Luis; Liebling, Steven L
2010-08-20
The coalescence of supermassive black holes--a natural outcome when galaxies merge--should produce gravitational waves and would likely be associated with energetic electromagnetic events. We have studied the coalescence of such binary black holes within an external magnetic field produced by the expected circumbinary disk surrounding them. Solving the Einstein equations to describe black holes interacting with surrounding plasma, we present numerical evidence for possible jets driven by these systems. Extending the process described by Blandford and Znajek for a single, spinning black hole, the picture that emerges suggests that the electromagnetic field extracts energy from the orbiting black holes, which ultimately merge and settle into the standard Blandford-Znajek scenario. Emissions along these jets could potentially be observable at large distances.
Black hole thermodynamics based on unitary evolutions
NASA Astrophysics Data System (ADS)
Feng, Yu-Lei; Chen, Yi-Xin
2015-10-01
In this paper, we try to construct black hole thermodynamics based on the fact that the formation and evaporation of a black hole can be described by quantum unitary evolutions. First, we show that the Bekenstein-Hawking entropy SBH may not be a Boltzmann or thermal entropy. To confirm this statement, we show that the original black hole's ‘first law’ may not simply be treated as the first law of thermodynamics formally, due to some missing metric perturbations caused by matter. Then, by including those (quantum) metric perturbations, we show that the black hole formation and evaporation can be described effectively in a unitary manner, through a quantum channel between the exterior and interior of the event horizon. In this way, the paradoxes of information loss and firewall can be resolved effectively. Finally, we show that black hole thermodynamics can be constructed in an ordinary way, by constructing statistical mechanics.
Black Holes at the LHC: Progress since 2002
Park, Seong Chan
2008-11-23
We review the recent noticeable progresses in black hole physics focusing on the up-coming super-collider, the LHC. We discuss the classical formation of black holes by particle collision, the greybody factors for higher dimensional rotating black holes, the deep implications of black hole physics to the 'energy-distance' relation, the security issues of the LHC associated with black hole formation and the newly developed Monte-Carlo generators for black hole events.
Hawking temperature of expanding cosmological black holes
Faraoni, Valerio
2007-11-15
In the context of a debate on the correct expression of the Hawking temperature of a cosmological black hole, we show that the correct expression in terms of the Hawking-Hayward quasilocal energy m{sub H} of the hole is T=(8{pi}m{sub H}(t)){sup -1}. This expression holds for comoving black holes and agrees with a recent proposal by Saida, Harada, and Maeda.
Numerical simulations of black-hole spacetimes
NASA Astrophysics Data System (ADS)
Chu, Tony
This thesis covers various aspects of the numerical simulation of black-hole spacetimes according to Einstein's general theory of relativity, using the Spectral Einstein Code developed by the Caltech-Cornell-CITA collaboration. The first topic is improvement of binary-black-hole initial data. One such issue is the construction of binary-black-hole initial data with nearly extremal spins that remain nearly constant during the initial relaxation in an evolution. Another concern is the inclusion of physically realistic tidal deformations of the black holes to reduce the high-frequency components of the spurious gravitational radiation content, and represents a first step in incorporating post-Newtonian results in constraint-satisfying initial data. The next topic is the evolution of black-hole binaries and the gravitational waves they emit. The first spectral simulation of two inspiralling black holes through merger and ringdown is presented, in which the black holes are nonspinning and have equal masses. This work is extended to perform the first spectral simulations of two inspiralling black holes with moderate spins and equal masses, including the merger and ringdown. Two configurations are considered, in which both spins are either anti-aligned or aligned with the orbital angular momentum. Highly accurate gravitational waveforms are computed for all these cases, and are used to calibrate waveforms in the effective-one-body model. The final topic is the behavior of quasilocal black-hole horizons in highly dynamical situations. Simulations of a rotating black hole that is distort ed by a pulse of ingoing gravitational radiation are performed. Multiple marginally outer trapped surfaces are seen to appear and annihilate with each other during the evolution, and the world tubes th ey trace out are all dynamical horizons. The dynamical horizon and angular momentum flux laws are evaluated in this context, and the dynamical horizons are contrasted with the event horizon
Black hole as a wormhole factory
NASA Astrophysics Data System (ADS)
Kim, Sung-Won; Park, Mu-In
2015-12-01
There have been lots of debates about the final fate of an evaporating black hole and the singularity hidden by an event horizon in quantum gravity. However, on general grounds, one may argue that a black hole stops radiation at the Planck mass (ħc / G) 1 / 2 ∼10-5 g, where the radiated energy is comparable to the black hole's mass. And also, it has been argued that there would be a wormhole-like structure, known as "spacetime foam", due to large fluctuations below the Planck length (ħG /c3) 1 / 2 ∼10-33 cm. In this paper, as an explicit example, we consider an exact classical solution which represents nicely those two properties in a recently proposed quantum gravity model based on different scaling dimensions between space and time coordinates. The solution, called "Black Wormhole", consists of two different states, depending on its mass parameter M and an IR parameter ω: For the black hole state (with ωM2 > 1 / 2), a non-traversable wormhole occupies the interior region of the black hole around the singularity at the origin, whereas for the wormhole state (with ωM2 < 1 / 2), the interior wormhole is exposed to an outside observer as the black hole horizon is disappearing from evaporation. The black hole state becomes thermodynamically stable as it approaches the merging point where the interior wormhole throat and the black hole horizon merges, and the Hawking temperature vanishes at the exact merge point (with ωM2 = 1 / 2). This solution suggests the "Generalized Cosmic Censorship" by the existence of a wormhole-like structure which protects the naked singularity even after the black hole evaporation. One could understand the would-be wormhole inside the black hole horizon as the result of microscopic wormholes created by "negative" energy quanta which have entered the black hole horizon in Hawking radiation process; the quantum black hole could be a wormhole factory! It is found that this speculative picture may be consistent with the recent " ER
The Smallest Supermassive Black Holes
NASA Astrophysics Data System (ADS)
Greene, Jenny
2012-03-01
I discuss our ongoing efforts to search for the smallest supermassive black holes (BHs) with masses of 10^4-10^6 Msun. The number density and location of these enigmatic sources provide some of our only observational constraints on the first primordial seed BHs. Merging BHs in this mass range are expected to be strong gravitational wave sources. Finally, since these BHs live in very different environments from their more massive cousins, they allow us to study the interactions between BHs and galaxies in a new way. Unfortunately, low-mass BHs are hard to find. I will discuss the known BHs in this mass regime and the path forward to a definitive understanding of the population.
Black Hole Binaries in Quiescence
NASA Astrophysics Data System (ADS)
Bailyn, Charles D.
I discuss some of what is known and unknown about the behavior of black hole binary systems in the quiescent accretion state. Quiescence is important for several reasons: 1) the dominance of the companion star in optical and IR wavelengths allows the binary parameters to be robustly determined - as an example, we argue that the longer proposed distance to the X-ray source GRO J1655-40 is correct; 2) quiescence represents the limiting case of an extremely low accretion rate, in which both accretion and jets can be observed; 3) understanding the evolution and duration of the quiescent state is a key factor in determining the overall demographics of X-ray binaries, which has taken on a new importance in the era of gravitational wave astronomy.
Making Supermassive Black Holes Spin
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2016-12-01
Where does the angular momentum come from that causes supermassive black holes (SMBHs) to spin on their axes and launch powerful jets? A new study of nearby SMBHs may help to answer this question.High-mass SMBHs are thought to form when two galaxies collide and the SMBHs at their centers merge. [NASA/Hubble Heritage Team (STScI)]High- vs. Low-Mass MonstersObservational evidence suggests a dichotomy between low-mass SMBHs (those with 106-7 M) and high-mass ones (those with 108-10 M). High-mass SMBHs are thought to form via the merger of two smaller black holes, and the final black hole is likely spun up by the rotational dynamics of the merger. But what spins up low-mass SMBHs, which are thought to build up very gradually via accretion?A team of scientists led by Jing Wang (National Astronomical Observatories, Chinese Academy of Sciences) have attempted to address this puzzle by examining the properties of the galaxies hosting low-mass SMBHs.A Sample of Neighboring SMBHsWang and collaborators began by constructing a sample of radio-selected nearby Seyfert 2 galaxies: those galaxies in which the stellar population and morphology of the host galaxy are visible to us, instead of being overwhelmed by continuum emission from the galaxys active nucleus.An example of a galaxy with a concentrated, classical bulge (M87; top) and a one with a disk-like pseudo bulge (Triangulum Galaxy; bottom). The authors find that for galaxies hosting low-mass SMBHs, those with more disk-like bulges appear to have more powerful radio jets. [Top: NASA/Hubble Heritage Team (STScI), Bottom: Hewholooks]From this sample, the authors then selected 31 galaxies that have low-mass SMBHs at their centers, as measured using the surrounding stellar dynamics. Wang and collaborators cataloged radio information revealing properties of the powerful jets launched by the SMBHs, and they analyzed the host galaxies properties by modeling their brightness profiles.Spin-Up From Accreting GasBy examining this
Evolution of Supermassive Black Holes
NASA Astrophysics Data System (ADS)
Filloux, Charline; de Freitas Pacheco, J. A.; Durier, Fabrice; Silk, Joseph
2010-05-01
Cosmological simulations describing both the evolution of supermassive black holes and their host galaxies were performed by using the tree PM-SPH code GADGET-2 (Springel 2005). Physical mechanisms affecting the dynamics and the physical conditions of the gas (ionization and cooling processes, local heating by stars, injection of mechanical energy by supernovae, chemical enrichment) were introduced in the present version of the code (Filloux 2009). Black holes in a state of accretion (AGNs) also inject mechanical energy in the surrounding medium, contributing for quenching the star formation activity. In all simulations a ΛCDM cosmology was adopted (h = 0.7, ΩΛ=0.7, Ωm=0.3, Ωb=0.046 and σ8=0.9). Simulations were performed in a volume with a side of 50h-1 Mpc, starting at z = 50 and through the present time (z = 0). For low and intermediate resolution runs, the initial gas mass particles are respectively 5.35× 108 M⊙ and 3.09×108 M⊙. Black holes (BHs) are represented by collisionless particles and seeds of 100 M⊙ were introduced in density peaks at z = 15, growing either by accretion or coalescence. The accretion rate from the “disk mode” is based on a turbulent viscous thin disk model whereas in the “spherical mode” the rate is given by the Bondi-Hoyle formula. When accreting matter, jets, modeled by conical regions perpendicular to the disk plane, inject kinetic energy into the surrounding medium. Two models were tested: in the first, the injected energy rate is about 10% of the gravitational energy rate released in the accretion process while in the second, the injected energy rate is based on the Blandford & Znajek (1977) mechanism. All simulations give, at z = 0, similar black hole mass function but they overestimate slightly the BH density for masses above ~ 108 M⊙. The resulting BH density in this mass range is affected by feedback processes since they control the amount of gas available for accretion. The present simulations are not
Black holes in massive gravity
NASA Astrophysics Data System (ADS)
Babichev, Eugeny; Brito, Richard
2015-08-01
We review the black hole (BH) solutions of the ghost-free massive gravity theory and its bimetric extension, and outline the main results on the stability of these solutions against small perturbations. Massive (bi)-gravity accommodates exact BH solutions, analogous to those of general relativity (GR). In addition to these solutions, hairy BHs—solutions with no correspondent in GR—have been found numerically, whose existence is a natural consequence of the absence of Birkhoff’s theorem in these theories. The existence of extra propagating degrees of freedom, makes the stability properties of these BHs richer and more complex than those of GR. In particular, the bi-Schwarzschild BH exhibits an unstable spherically symmetric mode, while the bi-Kerr geometry is also generically unstable, both against the spherical mode and against superradiant instabilities. If astrophysical BHs are described by these solutions, the superradiant instability of the Kerr solution imposes stringent bounds on the graviton mass.
Black holes in the Milky Way Galaxy
Filippenko, Alexei V.
1999-01-01
Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4–16 times the mass of the sun, whereas the latter are “supermassive black holes” with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong. PMID:10468548
NASA Astrophysics Data System (ADS)
2001-08-01
ISAAC Finds "Cool" Young Stellar Systems at the Centres of Active Galaxies Summary Supermassive Black Holes are present at the centres of many galaxies, some weighing hundreds of millions times more than the Sun. These extremely dense objects cannot be observed directly, but violently moving gas clouds and stars in their strong gravitational fields are responsible for the emission of energetic radiation from such "active galaxy nuclei" (AGN) . A heavy Black Hole feeds agressively on its surroundings . When the neighbouring gas and stars finally spiral into the Black Hole, a substantial fraction of the infalling mass is transformed into pure energy. However, it is not yet well understood how, long before this dramatic event takes place, all that material is moved from the outer regions of the galaxy towards the central region. So how is the food for the central Black Hole delivered to the table in the first place? To cast more light on this central question, a team of French and Swiss astronomers [1] has carried out a series of trailblazing observations with the VLT Infrared Spectrometer And Array Camera (ISAAC) on the VLT 8.2-m ANTU telescope at the ESO Paranal Observatory. The ISAAC instrument is particularly well suited to this type of observations. Visible light cannot penetrate the thick clouds of dust and gas in the innermost regions of active galaxies, but by recording the infrared light from the stars close to the Black Hole , their motions can be studied. By charting those motions in the central regions of three active galaxies (NGC 1097, NGC 1808 and NGC 5728), the astronomers were able to confirm the presence of "nuclear bars" in all three. These are dynamical structures that "open a road" for the flow of material towards the innermost region. Moreover, the team was surprised to discover signs of a young stellar population near the centres of these galaxies - stars that have apparently formed quite recently in a central gas disk. Such a system is unstable
Revisiting Black Holes as Dark Matter
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2017-02-01
Could dark matter be made of intermediate-mass black holes formed in the beginning of the universe? A recent study takes a renewed look at this question.Galactic LurkersThe nature of dark matter has long been questioned, but the recent discovery of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) has renewed interest in the possibility that dark matter could consist of primordial black holes in the mass range of 101000 solar masses.The relative amounts of the different constituents of the universe. Dark matter makes up roughly 27%. [ESA/Planck]According to this model, the extreme density of matter present during the universes early expansion led to the formation of a large number of intermediate-mass black holes. These black holes now hide in the halos of galaxies, constituting the mass that weve measured dynamically but remains unseen.LIGOs first gravitational-wave detection revealed the merger of two black holes that were both tens of solar masses in size. If primordial black holes are indeed a major constituent of dark matter, then LIGOs detection is consistent with what we would expect to find: occasional mergers of the intermediate-mass black holes that formed in the early universe and now lurk in galactic halos.Quasar MicrolensingTheres a catch, however. If there truly were a large number of intermediate-mass primordial black holes hiding in galactic halos, they wouldnt go completely unnoticed: we would see signs of their presence in the gravitational microlensing of background quasars. Unseen primordial black holes in a foreground galaxy could cause an image of a background quasar to briefly brighten which would provide us with clear evidence of such black holes despite our not being able to detect them directly.A depiction of quasar microlensing (click for a closer look!). The microlensing object in the foreground galaxy could be a star (as depicted), a primordial black hole, or any other compact object. [NASA
Extremal vacuum black holes in higher dimensions
Figueras, Pau; Lucietti, James; Rangamani, Mukund; Kunduri, Hari K.
2008-08-15
We consider extremal black hole solutions to the vacuum Einstein equations in dimensions greater than five. We prove that the near-horizon geometry of any such black hole must possess an SO(2,1) symmetry in a special case where one has an enhanced rotational symmetry group. We construct examples of vacuum near-horizon geometries using the extremal Myers-Perry black holes and boosted Myers-Perry strings. The latter lead to near-horizon geometries of black ring topology, which in odd spacetime dimensions have the correct number of rotational symmetries to describe an asymptotically flat black object. We argue that a subset of these correspond to the near-horizon limit of asymptotically flat extremal black rings. Using this identification we provide a conjecture for the exact 'phase diagram' of extremal vacuum black rings with a connected horizon in odd spacetime dimensions greater than five.
Black hole formation in a contracting universe
NASA Astrophysics Data System (ADS)
Quintin, Jerome; Brandenberger, Robert H.
2016-11-01
We study the evolution of cosmological perturbations in a contracting universe. We aim to determine under which conditions density perturbations grow to form large inhomogeneities and collapse into black holes. Our method consists in solving the cosmological perturbation equations in complete generality for a hydrodynamical fluid. We then describe the evolution of the fluctuations over the different length scales of interest and as a function of the equation of state for the fluid, and we explore two different types of initial conditions: quantum vacuum and thermal fluctuations. We also derive a general requirement for black hole collapse on sub-Hubble scales, and we use the Press-Schechter formalism to describe the black hole formation probability. For a fluid with a small sound speed (e.g., dust), we find that both quantum and thermal initial fluctuations grow in a contracting universe, and the largest inhomogeneities that first collapse into black holes are of Hubble size and the collapse occurs well before reaching the Planck scale. For a radiation-dominated fluid, we find that no black hole can form before reaching the Planck scale. In the context of matter bounce cosmology, it thus appears that only models in which a radiation-dominated era begins early in the cosmological evolution are robust against the formation of black holes. Yet, the formation of black holes might be an interesting feature for other models. We comment on a number of possible alternative early universe scenarios that could take advantage of this feature.
Discrete quantum spectrum of black holes
NASA Astrophysics Data System (ADS)
Lochan, Kinjalk; Chakraborty, Sumanta
2016-04-01
The quantum genesis of Hawking radiation is a long-standing puzzle in black hole physics. Semi-classically one can argue that the spectrum of radiation emitted by a black hole look very much sparse unlike what is expected from a thermal object. It was demonstrated through a simple quantum model that a quantum black hole will retain a discrete profile, at least in the weak energy regime. However, it was suggested that this discreteness might be an artifact of the simplicity of eigen-spectrum of the model considered. Different quantum theories can, in principle, give rise to different complicated spectra and make the radiation from black hole dense enough in transition lines, to make them look continuous in profile. We show that such a hope from a geometry-quantized black hole is not realized as long as large enough black holes are dubbed with a classical mass area relation in any gravity theory ranging from GR, Lanczos-Lovelock to f(R) gravity. We show that the smallest frequency of emission from black hole in any quantum description, is bounded from below, to be of the order of its inverse mass. That leaves the emission with only two possibilities. It can either be non-thermal, or it can be thermal only with the temperature being much larger than 1/M.
Particle creation rate for dynamical black holes
NASA Astrophysics Data System (ADS)
Firouzjaee, Javad T.; Ellis, George F. R.
2016-11-01
We present the particle creation probability rate around a general black hole as an outcome of quantum fluctuations. Using the uncertainty principle for these fluctuation, we derive a new ultraviolet frequency cutoff for the radiation spectrum of a dynamical black hole. Using this frequency cutoff, we define the probability creation rate function for such black holes. We consider a dynamical Vaidya model and calculate the probability creation rate for this case when its horizon is in a slowly evolving phase. Our results show that one can expect the usual Hawking radiation emission process in the case of a dynamical black hole when it has a slowly evolving horizon. Moreover, calculating the probability rate for a dynamical black hole gives a measure of when Hawking radiation can be killed off by an incoming flux of matter or radiation. Our result strictly suggests that we have to revise the Hawking radiation expectation for primordial black holes that have grown substantially since they were created in the early universe. We also infer that this frequency cut off can be a parameter that shows the primordial black hole growth at the emission moment.
Multipole moments of bumpy black holes
Vigeland, Sarah J.
2010-11-15
General relativity predicts the existence of black holes, compact objects whose spacetimes depend only on their mass, spin, and charge in vacuum (the 'no-hair' theorem). As various observations probe deeper into the strong fields of black hole candidates, it is becoming possible to test this prediction. Previous work suggested that such tests can be performed by measuring whether the multipolar structure of black hole candidates has the form that general relativity demands, and introduced a family of 'bumpy black hole' spacetimes to be used for making these measurements. These spacetimes have generalized multipoles, where the deviation from the Kerr metric depends on the spacetime's 'bumpiness'. In this paper, we show how to compute the Geroch-Hansen moments of a bumpy black hole, demonstrating that there is a clean mapping between the deviations used in the bumpy black hole formalism and the Geroch-Hansen moments. We also extend our previous results to define bumpy black holes whose current moments, analogous to magnetic moments of electrodynamics, deviate from the canonical Kerr value.
Black Hole Mergers in the Universe.
Portegies Zwart SF; McMillan
2000-01-01
Mergers of black hole binaries are expected to release large amounts of energy in the form of gravitational radiation. However, binary evolution models predict merger rates that are too low to be of observational interest. In this Letter, we explore the possibility that black holes become members of close binaries via dynamical interactions with other stars in dense stellar systems. In star clusters, black holes become the most massive objects within a few tens of millions of years; dynamical relaxation then causes them to sink to the cluster core, where they form binaries. These black hole binaries become more tightly bound by superelastic encounters with other cluster members and are ultimately ejected from the cluster. The majority of escaping black hole binaries have orbital periods short enough and eccentricities high enough that the emission of gravitational radiation causes them to coalesce within a few billion years. We predict a black hole merger rate of about 1.6x10-7 yr-1 Mpc-3, implying gravity-wave detection rates substantially greater than the corresponding rates from neutron star mergers. For the first-generation Laser Interferometer Gravitational-Wave Observatory (LIGO-I), we expect about one detection during the first 2 years of operation. For its successor LIGO-II, the rate rises to roughly one detection per day. The uncertainties in these numbers are large. Event rates may drop by about an order of magnitude if the most massive clusters eject their black hole binaries early in their evolution.
Black Holes Have Simple Feeding Habits
NASA Astrophysics Data System (ADS)
2008-06-01
The biggest black holes may feed just like the smallest ones, according to data from NASA’s Chandra X-ray Observatory and ground-based telescopes. This discovery supports the implication of Einstein's relativity theory that black holes of all sizes have similar properties, and will be useful for predicting the properties of a conjectured new class of black holes. The conclusion comes from a large observing campaign of the spiral galaxy M81, which is about 12 million light years from Earth. In the center of M81 is a black hole that is about 70 million times more massive than the Sun, and generates energy and radiation as it pulls gas in the central region of the galaxy inwards at high speed. In contrast, so-called stellar mass black holes, which have about 10 times more mass than the Sun, have a different source of food. These smaller black holes acquire new material by pulling gas from an orbiting companion star. Because the bigger and smaller black holes are found in different environments with different sources of material to feed from, a question has remained about whether they feed in the same way. Using these new observations and a detailed theoretical model, a research team compared the properties of M81's black hole with those of stellar mass black holes. The results show that either big or little, black holes indeed appear to eat similarly to each other, and produce a similar distribution of X-rays, optical and radio light. AnimationMulti-wavelength Images of M81 One of the implications of Einstein's theory of General Relativity is that black holes are simple objects and only their masses and spins determine their effect on space-time. The latest research indicates that this simplicity manifests itself in spite of complicated environmental effects. "This confirms that the feeding patterns for black holes of different sizes can be very similar," said Sera Markoff of the Astronomical Institute, University of Amsterdam in the Netherlands, who led the study
The Limits of Black Hole Complementarity
NASA Astrophysics Data System (ADS)
Susskind, Leonard
Black hole complementarity, as originally formulated in the 1990's by Preskill, 't Hooft, and myself is now being challenged by the Almheiri-Marolf-Polchinski-Sully firewall argument. The AMPS argument relies on an implicit assumption—the "proximity" postulate—which says that the interior of a black hole must be constructed from degrees of freedom that are physically near the black hole. The proximity postulate manifestly contradicts the idea that interior information is redundant with information in Hawking radiation, which is very far from the black hole. AMPS argue that a violation of the proximity postulate would lead to a contradiction in a thought-experiment in which Alice distills the Hawking radiation and brings a bit back to the black hole. According to AMPS the only way to protect against the contradiction is for a firewall to form at the Page time. But the measurement that Alice must make, is of such a fine-grained nature that carrying it out before the black hole evaporates may be impossible. Harlow and Hayden have found evidence that the limits of quantum computation do in fact prevent Alice from carrying out her experiment in less than exponential time. If their conjecture is correct then black hole complementarity may be alive and well. My aim here is to give an overview of the firewall argument, and its basis in the proximity postulate; as well as the counterargument based on computational complexity, as conjectured by Harlow and Hayden.
Black hole entanglement and quantum error correction
NASA Astrophysics Data System (ADS)
Verlinde, Erik; Verlinde, Herman
2013-10-01
It was recently argued in [1] that black hole complementarity strains the basic rules of quantum information theory, such as monogamy of entanglement. Motivated by this argument, we develop a practical framework for describing black hole evaporation via unitary time evolution, based on a holographic perspective in which all black hole degrees of freedom live on the stretched horizon. We model the horizon as a unitary quantum system with finite entropy, and do not postulate that the horizon geometry is smooth. We then show that, with mild assumptions, one can reconstruct local effective field theory observables that probe the black hole interior, and relative to which the state near the horizon looks like a local Minkowski vacuum. The reconstruction makes use of the formalism of quantum error correcting codes, and works for black hole states whose entanglement entropy does not yet saturate the Bekenstein-Hawking bound. Our general framework clarifies the black hole final state proposal, and allows a quantitative study of the transition into the "firewall" regime of maximally mixed black hole states.
Early black hole signals at the LHC
Koch, Ben; Bleicher, Marcus; Stoecker, Horst
2007-10-26
The production of mini black holes due to large extra dimensions is a speculative but possible scenario. We survey estimates for di-jet suppression, and multi-mono-jet emission due to black hole production. We further look for a possible sub-scenario which is the formation of a stable or meta-stable black hole remnant (BHR). We show that the beauty of such objects is, that they are relatively easy to observe, even in the early phase of LHC running.
Modeling Black Holes in Globular Clusters
NASA Astrophysics Data System (ADS)
Ivanova, Natalia
2013-04-01
I will review the current theoretical understanding of what is the population of black holes in globular clusters, as well as challenges in their modeling. Black hole binaries are the tip of the iceberg, and our best link to observations. In a dense stellar environment, such binaries are formed via dynamical encounters. The analyses show that the formation path of black hole X-ray binaries is very different from the well-known formation channels for neutron star X-ray binaries, like binary exchanges and physical collisions. This formation path is composed of several distinct formation stages, where the most crucial one is triple-induced mass transfer.
Microscopic Primordial Black Holes and Extra Dimensions
Conley, John A.; Wizansky, Tommer
2006-11-15
We examine the production and evolution of microscopic black holes in the early universe in the large extra dimensions scenario. We demonstrate that, unlike in the standard four-dimensional cosmology, in large extra dimensions absorption of matter from the primordial plasma by the black holes is significant and can lead to rapid growth of the black hole mass density. This effect can be used to constrain the conditions present in the very early universe. We demonstrate that this constraint is applicable in regions of parameter space not excluded by existing bounds.
Microscopic primordial black holes and extra dimensions
Conley, John; Wizansky, Tommer
2007-02-15
We examine the production and evolution of microscopic black holes in the early universe in the large extra dimensions scenario. We demonstrate that, unlike in the standard four-dimensional cosmology, in large extra dimensions absorption of matter from the primordial plasma by the black holes is significant and can lead to rapid growth of the black hole mass density. This effect can be used to constrain the conditions present in the very early universe. We demonstrate that this constraint is applicable in regions of parameter space not excluded by existing bounds.
Stationary Black Holes: Uniqueness and Beyond.
Chruściel, Piotr T; Costa, João Lopes; Heusler, Markus
2012-01-01
The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.
Some aspects of virtual black holes
Faizal, M.
2012-03-15
We first consider consistently third-quantize modified gravity. We then analyze certain aspects of virtual black holes in this third-quantized modified gravity. We see how a statistical mechanical origin for the Bekenstein-Hawking entropy naturally arises in this model. Furthermore, the area and hence the entropy of a real macroscopic black hole is quantized in this model. Virtual black holes cause a loss of quantum coherence, which gives an intrinsic entropy to all physical systems that can be used to define a direction of time and hence provide a solution to the problem of time.
Black hole mining in the RST model
NASA Astrophysics Data System (ADS)
Basavaraju, Rohitvarma; Lowe, David A.
2017-06-01
We consider the possibility of mining black holes in the 1 + 1-dimensional dilaton gravity model of Russo, Susskind and Thorlacius. The model correctly incorporates Hawking radiation and back-reaction in a semiclassical expansion in 1/N, where N is the number of matter species. It is shown that the lifetime of a perturbed black hole is independent of the addition of any extra apparatus when realized by an arbitrary positive energy matter source. We conclude that mining does not occur in the RST model and comment on the implications of this for the black hole information paradox.
Magnetically charged black holes and their stability
Aichelburg, P.C. ); Bizon, P. )
1993-07-15
We study magnetically charged black holes in the Einstein-Yang-Mills-Higgs theory in the limit of infinitely strong coupling of the Higgs field. Using mixed analytical and numerical methods we give a complete description of static spherically symmetric black hole solutions, both Abelian and non-Abelian. In particular, we find a new class of extremal non-Abelian solutions. We show that all non-Abelian solutions are stable against linear radial perturbations. The implications of our results for the semiclassical evolution of magnetically charged black holes are discussed.
The primordial black hole mass range
NASA Astrophysics Data System (ADS)
Frampton, Paul H.
2016-04-01
We investigate Primordial Black Hole (PBH) formation by which we mean black holes produced in the early Universe during radiation domination. After discussing the range of PBH mass permitted in the original mechanism of Carr and Hawking, hybrid inflation with parametric resonance is presented as an existence theorem for PBHs of arbitrary mass. As proposed in arXiv:1510.00400, PBHs with many solar masses can provide a solution to the dark matter problem in galaxies. PBHs can also explain dark matter observed in clusters and suggest a primordial origin for Supermassive Black Holes (SMBHs) in galactic cores.
Entanglement entropy of subtracted geometry black holes
NASA Astrophysics Data System (ADS)
Cvetič, Mirjam; Saleem, Zain H.; Satz, Alejandro
2014-09-01
We compute the entanglement entropy of minimally coupled scalar fields on subtracted geometry black hole backgrounds, focusing on the logarithmic corrections. We notice that matching between the entanglement entropy of original black holes and their subtracted counterparts is only at the order of the area term. The logarithmic correction term is not only different but also, in general, changes sign in the subtracted case. We apply Harrison transformations to the original black holes and find out the choice of the Harrison parameters for which the logarithmic corrections vanish.
Relativistic Magnetic Reconnection around rotating black holes
NASA Astrophysics Data System (ADS)
Asenjo, Felipe; Comisso, Luca
2016-10-01
In recent years, the classical Sweet-Parker and Petschek models have been extended in the special relativistic regime, both for MHD plasmas and two-fluid electron-positron plasmas. Nevertheless, there could be situations, like in the vicinity of black holes, where also general relativistic effects can become important. Here, we calculate analytically the reconnection rate and other relevant quantities in a magnetic reconnection process around a rotating black hole. A striking result is that the black hole rotation is capable to produce an enhancement of the rate at which magnetic reconnection proceeds. This work is supported by Fondecyt-Chile, Grant No. 11140025.
Black hole ringdown echoes and howls
NASA Astrophysics Data System (ADS)
Nakano, Hiroyuki; Sago, Norichika; Tagoshi, Hideyuki; Tanaka, Takahiro
2017-07-01
Recently the possibility of detecting echoes of ringdown gravitational waves from binary black hole mergers was shown. The presence of echoes is expected if the black hole is surrounded by a mirror that reflects gravitational waves near the horizon. Here, we present slightly more sophisticated templates motivated by a waveform which is obtained by solving the linear perturbation equation around a Kerr black hole with a complete reflecting boundary condition in the stationary traveling wave approximation. We estimate that the proposed template can bring about a 10% improvement in the signal-to-noise ratio.
Central black hole masses of galaxies
NASA Astrophysics Data System (ADS)
Fan, Jun-Hui
2003-11-01
In this paper, the stellar velocity dispersions in the host galaxies are used to estimate the central black hole masses for a sample of elliptical galaxies. We find that the central black hole masses are in the range of 10(5.5-9.5)Modot. Based on the estimated masses in this paper and those by Woo & Urry (2002) and the measured host galaxy absolute magnitude, a relation, log (MBH/Modot) = -(0.25±4.3×10-3)MR + (2.98±0.208) is found for central black hole mass and the host galaxy magnitude. Some discussions are presented.
Interacting quantum fields around a black hole
NASA Astrophysics Data System (ADS)
Hawking, S. W.
1981-09-01
If one studies interacting fields on a black hole background using ordinary Feynman diagrams, one is faced with a problem of what to do with lines that cross the horizon. To avoid this difficulty a formulation is developed which can be expressed graphically in terms of a new class of diagram with external lines only at infinity. This formalism is applied to study the question of whether spontaneously broken symmetry would be restored near the black hole. It is also used to show that a black hole can emit more particles than antiparticles even in theories where the particle number is locally conserved by a global U(1) symmetry.
Black Holes and the Information Paradox
NASA Astrophysics Data System (ADS)
't Hooft, Gerard
In electromagnetism, like charges repel, opposite charges attract. A remarkable feature of the gravitational force is that like masses attract. This gives rise to an instability: the more mass you have, the stronger the attractive force, until an inevitable implosion follows, leading to a "black hole". It is in the black hole where an apparent conflict between Einstein's General Relativity and the laws of Quantum Mechanics becomes manifest. Most physicists now agree that a black hole should be described by a Schrödinger equation, with a Hermitean Hamiltonian, but this requires a modification of general relativity. Both General Relativity and Quantum mechanics are shaking on their foundations.
Testing black hole candidates with electromagnetic radiation
NASA Astrophysics Data System (ADS)
Bambi, Cosimo
2017-04-01
Astrophysical black hole candidates are thought to be the Kerr black holes of general relativity, but there is not yet direct observational evidence that the spacetime geometry around these objects is described by the Kerr solution. The study of the properties of the electromagnetic radiation emitted by gas or stars orbiting these objects can potentially test the Kerr black hole hypothesis. This paper reviews the state of the art of this research field, describing the possible approaches to test the Kerr metric with current and future observational facilities and discussing current constraints.
NuSTAR Seeks Hidden Black Holes
2015-07-06
Top: An illustration of NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, in orbit. The unique school bus-long mast allows NuSTAR to focus high energy X-rays. Lower-left: A color image from NASA's Hubble Space Telescope of one of the nine galaxies targeted by NuSTAR in search of hidden black holes. Bottom-right: An artist's illustration of a supermassive black hole, actively feasting on its surroundings. The central black hole is hidden from direct view by a thick layer of encircling gas and dust. http://photojournal.jpl.nasa.gov/catalog/PIA19348
Early black hole signals at the LHC
NASA Astrophysics Data System (ADS)
Koch, Ben; Bleicher, Marcus; Stöcker, Horst
2007-10-01
The production of mini black holes due to large extra dimensions is a speculative but possible scenario. We survey estimates for di-jet suppression, and multi-mono-jet emission due to black hole production. We further look for a possible sub-scenario which is the formation of a stable or meta-stable black hole remnant (BHR). We show that the beauty of such objects is, that they are relatively easy to observe, even in the early phase of LHC running.
Three charge supertubes and black hole hair
NASA Astrophysics Data System (ADS)
Bena, Iosif; Kraus, Per
2004-08-01
We construct finite size, supersymmetric, tubular D-brane configurations with three charges, two angular momenta and several brane dipole moments. In type IIA string theory these are tubular configurations with D0, D4 and F1 charge, as well as D2, D6 and NS5 dipole moments. These multicharge generalizations of supertubes might have interesting consequences for the physics of the D1-D5-P black hole. We study the relation of the tubes to the spinning Breckenridge-Myers-Peet-Vafa black hole, and find that they have properties consistent with describing some of the hair of this black hole.
Entropy Inequality Violations from Ultraspinning Black Holes.
Hennigar, Robie A; Mann, Robert B; Kubizňák, David
2015-07-17
We construct a new class of rotating anti-de Sitter (AdS) black hole solutions with noncompact event horizons of finite area in any dimension and study their thermodynamics. In four dimensions these black holes are solutions to gauged supergravity. We find that their entropy exceeds the maximum implied from the conjectured reverse isoperimetric inequality, which states that for a given thermodynamic volume, the black hole entropy is maximized for Schwarzschild-AdS space. We use this result to suggest more stringent conditions under which this conjecture may hold.
Neutron tori around Kerr black holes
NASA Technical Reports Server (NTRS)
Witt, H. J.; Jaroszynski, M.; Haensel, P.; Paczynski, B.; Wambsganss, J.
1994-01-01
Models of stationary, axisymmetric, non-self-gravitating tori around stellar mass Kerr black holes are calculated. Such objects may form as a result of a merger between two neutron stars, a neutron star and a stellar mass black hole, or a 'failed supernova' collapse of a single rapidly rotating star. We explore a large range of parameters: the black hole mass and angular momentum, the torus mass, angular momentum and entropy. Physical conditions within the tori are similar to those in young and hot neutron stars, but their topology is different, and the range of masses and energies is much larger.
Spectroscopy and Thermodynamics of MSW Black Hole
NASA Astrophysics Data System (ADS)
Sebastian, Saneesh; Kuriakose, V. C.
2013-10-01
We study the thermodynamics and spectroscopy of a (2+1)-dimensional black hole proposed by Mandal et al.1 [Mod. Phys. Lett. A6, 1685 (1991)]. We put the background spacetime in Kruskal like co-ordinate and find period with respect to Euclidean time. Different thermodynamic quantities like entropy, specific heat, temperature etc. are obtained. The adiabatic invariant for the black hole is found and quantized using Bohr-Sommerfeld quantization rule. The study shows that the area spectrum of MSW black hole is equally spaced and the value of spacing is found to be ℏ.
Stellar black holes in globular clusters
NASA Technical Reports Server (NTRS)
Kulkarni, S. R.; Hut, Piet; Mcmillan, Steve
1993-01-01
The recent discovery of large populations of millisec pulsars associated with neutron stars in globular clusters indicates that several hundred stellar black holes of about 10 solar masses each can form within a typical cluster. While, in clusters of high central density, the rapid dynamical evolution of the black-hole population leads to an ejection of nearly all holes on a short timescale, systems of intermediate density may involve a normal star's capture by one of the surviving holes to form a low-mass X-ray binary. One or more such binaries may be found in the globular clusters surrounding our galaxy.
Stellar black holes in globular clusters
NASA Technical Reports Server (NTRS)
Kulkarni, S. R.; Hut, Piet; Mcmillan, Steve
1993-01-01
The recent discovery of large populations of millisec pulsars associated with neutron stars in globular clusters indicates that several hundred stellar black holes of about 10 solar masses each can form within a typical cluster. While, in clusters of high central density, the rapid dynamical evolution of the black-hole population leads to an ejection of nearly all holes on a short timescale, systems of intermediate density may involve a normal star's capture by one of the surviving holes to form a low-mass X-ray binary. One or more such binaries may be found in the globular clusters surrounding our galaxy.
Surprise: Dwarf Galaxy Harbors Supermassive Black Hole
NASA Astrophysics Data System (ADS)
2011-01-01
The surprising discovery of a supermassive black hole in a small nearby galaxy has given astronomers a tantalizing look at how black holes and galaxies may have grown in the early history of the Universe. Finding a black hole a million times more massive than the Sun in a star-forming dwarf galaxy is a strong indication that supermassive black holes formed before the buildup of galaxies, the astronomers said. The galaxy, called Henize 2-10, 30 million light-years from Earth, has been studied for years, and is forming stars very rapidly. Irregularly shaped and about 3,000 light-years across (compared to 100,000 for our own Milky Way), it resembles what scientists think were some of the first galaxies to form in the early Universe. "This galaxy gives us important clues about a very early phase of galaxy evolution that has not been observed before," said Amy Reines, a Ph.D. candidate at the University of Virginia. Supermassive black holes lie at the cores of all "full-sized" galaxies. In the nearby Universe, there is a direct relationship -- a constant ratio -- between the masses of the black holes and that of the central "bulges" of the galaxies, leading them to conclude that the black holes and bulges affected each others' growth. Two years ago, an international team of astronomers found that black holes in young galaxies in the early Universe were more massive than this ratio would indicate. This, they said, was strong evidence that black holes developed before their surrounding galaxies. "Now, we have found a dwarf galaxy with no bulge at all, yet it has a supermassive black hole. This greatly strengthens the case for the black holes developing first, before the galaxy's bulge is formed," Reines said. Reines, along with Gregory Sivakoff and Kelsey Johnson of the University of Virginia and the National Radio Astronomy Observatory (NRAO), and Crystal Brogan of the NRAO, observed Henize 2-10 with the National Science Foundation's Very Large Array radio telescope and
Surprise: Dwarf Galaxy Harbors Supermassive Black Hole
NASA Astrophysics Data System (ADS)
2011-01-01
The surprising discovery of a supermassive black hole in a small nearby galaxy has given astronomers a tantalizing look at how black holes and galaxies may have grown in the early history of the Universe. Finding a black hole a million times more massive than the Sun in a star-forming dwarf galaxy is a strong indication that supermassive black holes formed before the buildup of galaxies, the astronomers said. The galaxy, called Henize 2-10, 30 million light-years from Earth, has been studied for years, and is forming stars very rapidly. Irregularly shaped and about 3,000 light-years across (compared to 100,000 for our own Milky Way), it resembles what scientists think were some of the first galaxies to form in the early Universe. "This galaxy gives us important clues about a very early phase of galaxy evolution that has not been observed before," said Amy Reines, a Ph.D. candidate at the University of Virginia. Supermassive black holes lie at the cores of all "full-sized" galaxies. In the nearby Universe, there is a direct relationship -- a constant ratio -- between the masses of the black holes and that of the central "bulges" of the galaxies, leading them to conclude that the black holes and bulges affected each others' growth. Two years ago, an international team of astronomers found that black holes in young galaxies in the early Universe were more massive than this ratio would indicate. This, they said, was strong evidence that black holes developed before their surrounding galaxies. "Now, we have found a dwarf galaxy with no bulge at all, yet it has a supermassive black hole. This greatly strengthens the case for the black holes developing first, before the galaxy's bulge is formed," Reines said. Reines, along with Gregory Sivakoff and Kelsey Johnson of the University of Virginia and the National Radio Astronomy Observatory (NRAO), and Crystal Brogan of the NRAO, observed Henize 2-10 with the National Science Foundation's Very Large Array radio telescope and
MODELING FLOWS AROUND MERGING BLACK HOLE BINARIES
Van Meter, James R.; Centrella, Joan; Baker, John G.; Boggs, William D.; Kelly, Bernard J.; McWilliams, Sean T.; Wise, John H.; Miller, M. Coleman; Reynolds, Christopher S.
2010-03-10
Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne Laser Interferometer Space Antenna. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step toward solving this problem by mapping the flow of pressureless matter in the dynamic, three-dimensional general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm these differences, it may allow assessment of the properties of the binaries as well as yielding an identifiable electromagnetic counterpart to the attendant gravitational wave signal.
How big can a black hole grow?
NASA Astrophysics Data System (ADS)
King, Andrew
2016-02-01
I show that there is a physical limit to the mass of a black hole, above which it cannot grow through luminous accretion of gas, and so cannot appear as a quasar or active galactic nucleus (AGN). The limit is Mmax ≃ 5 × 1010 M⊙ for typical parameters, but can reach Mmax ≃ 2.7 × 1011 M⊙ in extreme cases (e.g. maximal prograde spin). The largest black hole masses so far found are close to but below the limit. The Eddington luminosity ≃6.5 × 1048 erg s-1 corresponding to Mmax is remarkably close to the largest AGN bolometric luminosity so far observed. The mass and luminosity limits both rely on a reasonable but currently untestable hypothesis about AGN disc formation, so future observations of extreme supermassive black hole masses can therefore probe fundamental disc physics. Black holes can in principle grow their masses above Mmax by non-luminous means such as mergers with other holes, but cannot become luminous accretors again. They might nevertheless be detectable in other ways, for example through gravitational lensing. I show further that black holes with masses ˜Mmax can probably grow above the values specified by the black-hole-host-galaxy scaling relations, in agreement with observation.
NASA Astrophysics Data System (ADS)
Holley-Bockelmann, Kelly
2016-04-01
Astronomers now know that supermassive black holes reside in nearly every galaxy.Though these black holes are an observational certainty, nearly every aspect of their evolution -- from their birth, to their fuel source, to their basic dynamics -- is a matter of lively debate. In principle, gas-rich major galaxy mergers can generate the central stockpile of fuel needed for a low mass central black hole seed to grow quickly into a supermassive one. During a galaxy merger, the black holes in each galaxy meet and form a supermassive binary black hole; as the binary orbit shrinks through its final parsec, it becomes the loudest gravitational wave source in the Universe and a powerful agent to sculpt the galactic center. This talk will touch on some current and ongoing work on refining our theories of how supermassive black hole binaries form, evolve within, and alter their galaxy host.
Destruction and recreation of black holes
NASA Astrophysics Data System (ADS)
Bell, Peter M.
Even though the existence of the gravitationally collapsed concentrations of matter in space known as ‘black holes’ is accepted at all educational levels in our society, the basis for the black hole concept is really only the result of approximate calculations done over 40 years ago. The concept of the black hole is an esoteric subject, and recently the mathematical and physical frailties of the concept have come to light in an interesting round of theoretical shuffling. The recent activity in theorizing about black holes began about 10 years ago, when Cambridge University mathematican Stephen Hawking calculated that black holes could become unstable by losing mass and thus ‘evaporate.’ Hawking's results were surprisingly well received, considering the lack of theoretical understanding of the relations between quantum mechanics and relativity. (There is no quantized theory of gravitation, even today.) Nonetheless, his semiclassical calculations implied that the rate of ‘evaporation’ of a black hole would be slower than the rate of degradation of the universe. In fact, based on these and other calculations, the British regard Hawking as ‘the nearest thing we have to a new Einstein’ [New Scientist, Oct. 9, 1980]. Within the last few months, Frank Tipler, provocative mathematical physicist at the University of Texas, has reexamined Hawking's calculations [Physical Review Letters, 45, 941, 1980], concluding, in simple terms, (1) that because of possible vital difficulties in the assumptions, the very concept of black holes could be wrong; (2) that Hawkings' evaporation hypothesis is so efficient that a black hole once created must disappear in less than a second; or (3) that he, Tipler, may be wrong. The latter possibility has been the conclusion of physicist James Bardeen of the University of Washington, who calculated that black hole masses do evaporate but they do so according to Hawking's predicted rate and that Tipler's findings cause only a second
Self stimulated particles generation by black holes
NASA Astrophysics Data System (ADS)
Gaina, Alex
2005-10-01
The Ideea of Black Holes Bomb was one of the most intriguing in the gravitational physics. Bohr was the first who quantized the levels of an atom. Subsequently his disciple J. A. Wheeler (1971) quantized the mass spin 0 and 1/2 levels near a black hole, described by a Schwarzschild metric. It is strange, but after this work the interest was drawn to Kerr black holes, due to discovery of particles generation by Ya. B. Zel'dovich and Ch. Misner in 1972. As a result, the ideea of a Black Holes bomb was announced by W.H. Press and S. Teukolsky in 1972. L.Ford (1975) observed, that test particles mass plays a role of a mirror, which could develope an instability. That ideea was independently discussed by Deruelle and Ruffini (1974) and Damour, Deruelle and Rufffini (1976), using WKB approach, while the analytic treatment of the bound levels problem in Kerr field for microscopically small black holes and mass particles was given by Ternov, Khalilov, Chizhov and Gaina (1978) and A. Vilenkin (1978) for a Kerr black hole inside a mirror. Once a particle could be localized on a bound level near a non-rotating (Schwarzschild ) black hole, due to stimulation, it will induces generation of another particles with the same quantum numbers (on the same level). This process will be a self-stimulated generation of particles, which was discussed in the literature by R. Wald and J. York, Jr. The accumulatiion of bosons on the bound levels, particularly on the s-bound level, will be exponentially fast for microscopically small black holes and will lead to a true instablity of Schwarzschild black holes. This is valid for bosons only, since the Fermi-Dirac statistics interdicts the accumulation of more than two particles with oposite spin. As a result the Black Holes mass will be limited M>= 8"pi"/5 x (M(pl))^2/m , where m is the scalar particles minimal rest mass, existing in nature, since the maximal growing rate for the instability is occuring for mM=8"pi"/5(M(pl))^2. If photon have a
Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations
NASA Astrophysics Data System (ADS)
Dvali, Gia; Gußmann, Alexander
2016-12-01
We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.
Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole
Myung, Yun Soo
2008-05-15
We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization.
NASA Astrophysics Data System (ADS)
Hurd, Randy; Pan, Zhao; Meritt, Andrew; Belden, Jesse; Truscott, Tadd
2015-11-01
Since the mid-nineteenth century, both enlisted and fashion-conscious owners of khaki trousers have been plagued by undesired speckle patterns resulting from splash-back while urinating. In recent years, industrial designers and hygiene-driven entrepreneurs have sought to limit this splashing by creating urinal inserts, with the effectiveness of their inventions varying drastically. From this large assortment of inserts, designs consisting of macroscopic pillar arrays seem to be the most effective splash suppressers. Interestingly this design partially mimics the geometry of the water capturing moss Syntrichia caninervis, which exhibits a notable ability to suppress splash and quickly absorb water from impacting rain droplets. With this natural splash suppressor in mind, we search for the ideal urine black hole by performing experiments of simulated urine streams (water droplet streams) impacting macroscopic pillar arrays with varying parameters including pillar height and spacing, draining and material properties. We propose improved urinal insert designs based on our experimental data in hopes of reducing potential embarrassment inherent in wearing khakis.
Black holes, bandwidths and Beethoven
NASA Astrophysics Data System (ADS)
Kempf, Achim
2000-04-01
It is usually believed that a function φ(t) whose Fourier spectrum is bounded can vary at most as fast as its highest frequency component ωmax. This is, in fact, not the case, as Aharonov, Berry, and others drastically demonstrated with explicit counterexamples, so-called superoscillations. It has been claimed that even the recording of an entire Beethoven symphony can occur as part of a signal with a 1 Hz bandwidth. Bandlimited functions also occur as ultraviolet regularized fields. Their superoscillations have been suggested, for example, to resolve the trans-Planckian frequencies problem of black hole radiation. Here, we give an exact proof for generic superoscillations. Namely, we show that for every fixed bandwidth there exist functions that pass through any finite number of arbitrarily prespecified points. Further, we show that, in spite of the presence of superoscillations, the behavior of bandlimited functions can be characterized reliably, namely through an uncertainty relation: The standard deviation ΔT of samples φ(tn) taken at the Nyquist rate obeys ΔT>=1/4ωmax. This uncertainty relation generalizes to variable bandwidths. For ultraviolet regularized fields we identify the bandwidth as the in general spatially variable finite local density of degrees of freedom.
Black holes as gravitational atoms
NASA Astrophysics Data System (ADS)
Vaz, Cenalo
2014-06-01
Recently, it was argued [A. Almheiri et al., arXiv: 1207.3123, A. Almheiri et al., arXiv: 1304.6483], via a delicate thought experiment, that it is not consistent to simultaneously require that (a) Hawking radiation is pure, (b) effective field theory is valid outside a stretched horizon and (c) infalling observers encounter nothing unusual as they cross the horizon. These are the three fundamental assumptions underlying Black Hole Complementarity and the authors proposed that the most conservative resolution of the paradox is that (c) is false and the infalling observer burns up at the horizon (the horizon acts as a "firewall"). However, the firewall violates the equivalence principle and breaks the CPT invariance of quantum gravity. This led Hawking to propose recently that gravitational collapse may not end up producing event horizons, although he did not give a mechanism for how this may happen. Here we will support Hawking's conclusion in a quantum gravitational model of dust collapse. We will show that continued collapse to a singularity can only be achieved by combining two independent and entire solutions of the Wheeler-DeWitt equation. We interpret the paradox as simply forbidding such a combination. This leads naturally to a picture in which matter condenses on the apparent horizon during quantum collapse.
Galaxies of all Shapes Host Black Holes
NASA Technical Reports Server (NTRS)
2008-01-01
This artist's concept illustrates the two types of spiral galaxies that populate our universe: those with plump middles, or central bulges (upper left), and those lacking the bulge (foreground).
New observations from NASA's Spitzer Space Telescope provide strong evidence that the slender, bulgeless galaxies can, like their chubbier counterparts, harbor supermassive black holes at their cores. Previously, astronomers thought that a galaxy without a bulge could not have a supermassive black hole. In this illustration, jets shooting away from the black holes are depicted as thin streams.
The findings are reshaping theories of galaxy formation, suggesting that a galaxy's 'waistline' does not determine whether it will be home to a big black hole.
Quasars, pulsars, black holes and HEAO's
NASA Technical Reports Server (NTRS)
Doolitte, R. F.; Moritz, K.; Whilden, R. D. C.
1974-01-01
Astronomical surveys are discussed by large X-ray, gamma ray, and cosmic ray instruments carried onboard high-energy astronomy observatories. Quasars, pulsars, black holes, and the ultimate benefits of the new astronomy are briefly discussed.
Shadow of rotating regular black holes
NASA Astrophysics Data System (ADS)
Abdujabbarov, Ahmadjon; Amir, Muhammed; Ahmedov, Bobomurat; Ghosh, Sushant G.
2016-05-01
We study the shadows cast by the different types of rotating regular black holes viz. Ayón-Beato-García (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*). 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 values 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.
Black Hole Observations - Towards the Event Horizon
NASA Astrophysics Data System (ADS)
Britzen, Silke
Black Holes are probably the most elusive solutions of Einstein's theory of General Relativity. Despite numerous observations of the direct galactic environment and indirect influence of astrophysical black holes (e.g. jets, variable emission across the wavelength spectrum, feedback processes, etc.) -- a direct proof of their existence is still lacking. This article highlights some aspects deduced from many observations and concentrates on the experimental results with regard to black holes with masses from millions to billions of solar masses. The focus will be on the challenges and remaining questions. The Event Horizon Telescopce (EHT) project to image the photon sphere of Sgr A* and its potential is briefly sketched. This instrumental approach shall lead to highest resolution observations of the supermassive black hole at the center of the Milky Way (Sgr A*).
The signature of a black hole transit
NASA Technical Reports Server (NTRS)
Dolan, Joseph F.
1989-01-01
This paper considers the possibility of identifying a black hole on the basis of the detection of some unique effect occurring during the transit of a black hole across the stellar disk of a companion star in a binary system. The results of Monte-Carlo calculations show that the amplitude of the photometric and polarimetric light curves in a typical X-ray binary is too small to be observed with present instrumentation, but that a black hole transit might be detectable in a binary having a large separation of the components. No binary system suggested as containing a stellar-mass-sized black hole is a like candidate to exhibit an observable transit signature, with the possible exception of X Persei/4U0352+30 described by White et al. (1976).
NASA Astrophysics Data System (ADS)
Miller, Jon M.
2017-08-01
Across the mass scale, high-resolution X-ray spectroscopy has transformed our view of accretion onto black holes. The ionized disk winds observed from stellar-mass black holes may sometimes eject more mass than is able to accrete onto the black hole. It is possible that these winds can probe the fundamental physics that drive disk accretion. The most powerful winds from accretion onto massive black holes may play a role in feedback, seeding host bulges with hot gas and halting star formation. The lessons and techniques emerging from these efforts can also reveal the accretion flow geometry in tidal disruption events (TDEs), an especially rich discovery space. This talk will review some recent progress enabled by high-resolution X-ray spectroscopy, and look at the potential of gratings spectrometers and microcalorimeters in the years ahead.
White Dwarfs, Neutron Stars and Black Holes
ERIC Educational Resources Information Center
Szekeres, P.
1977-01-01
The three possible fates of burned-out stars: white dwarfs, neutron stars and black holes, are described in elementary terms. Characteristics of these celestial bodies, as provided by Einstein's work, are described. (CP)
Black Holes: The making of a monster
NASA Astrophysics Data System (ADS)
Mayer, Lucio
2017-04-01
The biggest black holes in the Universe were in place soon after the Big Bang. Explaining how they formed so rapidly is a daunting challenge, but the latest simulations give clues to how this may have occurred.
Black hole evolution by spectral methods
NASA Astrophysics Data System (ADS)
Kidder, Lawrence E.; Scheel, Mark A.; Teukolsky, Saul A.; Carlson, Eric D.; Cook, Gregory B.
2000-10-01
Current methods of evolving a spacetime containing one or more black holes are plagued by instabilities that prohibit long-term evolution. Some of these instabilities may be due to the numerical method used, traditionally finite differencing. In this paper, we explore the use of a pseudospectral collocation (PSC) method for the evolution of a spherically symmetric black hole spacetime in one dimension using a hyperbolic formulation of Einstein's equations. We demonstrate that our PSC method is able to evolve a spherically symmetric black hole spacetime forever without enforcing constraints, even if we add dynamics via a Klein-Gordon scalar field. We find that, in contrast with finite-differencing methods, black hole excision is a trivial operation using PSC applied to a hyperbolic formulation of Einstein's equations. We discuss the extension of this method to three spatial dimensions.
Primordial Black Holes from First Principles (Overview)
NASA Astrophysics Data System (ADS)
Lam, Casey; Bloomfield, Jolyon; Moss, Zander; Russell, Megan; Face, Stephen; Guth, Alan
2017-01-01
Given a power spectrum from inflation, our goal is to calculate, from first principles, the number density and mass spectrum of primordial black holes that form in the early universe. Previously, these have been calculated using the Press- Schechter formalism and some demonstrably dubious rules of thumb regarding predictions of black hole collapse. Instead, we use Monte Carlo integration methods to sample field configurations from a power spectrum combined with numerical relativity simulations to obtain a more accurate picture of primordial black hole formation. We demonstrate how this can be applied for both Gaussian perturbations and the more interesting (for primordial black holes) theory of hybrid inflation. One of the tools that we employ is a variant of the BBKS formalism for computing the statistics of density peaks in the early universe. We discuss the issue of overcounting due to subpeaks that can arise from this approach (the ``cloud-in-cloud'' problem). MIT UROP Office- Paul E. Gray (1954) Endowed Fund.
Forming Binary Black Holes in Galactic Mergers
NASA Astrophysics Data System (ADS)
Quinn, Thomas R.; Roskar, R.; Mayer, L.; Kazantzidis, S.
2010-01-01
As galaxies merge in the standard hierarchical scenario of galaxy formation, their central Black Holes also can merge and grow. The violent dynamics of the galaxy merger will deliver a significant amount of gas and stars to the central regions of the galaxy further growing the central Black Hole and fueling an Active Galactic Nucleus. We perform state-of-art numerical simulations of this merging process using N-body simulations and gas dynamics. These simulations resolved the dynamics in the central kiloparsec of the merging galaxies, and enable us to follow the sinking of the Black Holes to the center via dynamical friction up to the formation of binary Black Holes. Critical to this process is the state of the surrounding gas which we follow with an equation of state that includes star formation and supernova feedback. This work is supported by a grant from NASA.
Energy conservation for dynamical black holes.
Hayward, Sean A
2004-12-17
An energy conservation law is described, expressing the increase in mass-energy of a general black hole in terms of the energy densities of the infalling matter and gravitational radiation. This first law of black-hole dynamics describes how a black hole grows and is regular in the limit where it ceases to grow. An effective gravitational-radiation energy tensor is obtained, providing measures of both ingoing and outgoing, transverse and longitudinal gravitational radiation on and near a black hole. Corresponding energy-tensor forms of the first law involve a preferred time vector which plays the role of a stationary Killing vector. Identifying an energy flux, vanishing if and only if the horizon is null, allows a division into energy supply and work terms. The energy supply can be expressed in terms of area increase and a newly defined surface gravity, yielding a Gibbs-like equation.
Black holes and the positive cosmological constant
NASA Astrophysics Data System (ADS)
Bhattacharya, Sourav
2013-02-01
We address some aspects of black hole spacetimes endowed with a positive cosmological constant, i.e. black holes located inside a cosmological event horizon. First we establish a general criterion for existence of cosmological event horizons. Using the geometrical set up built for this, we study classical black hole no hair theorems for both static and stationary axisymmetric spacetimes. We discuss cosmic Nielsen-Olesen strings as hair in Schwarzschild-de Sitter spacetime. We also give a general calculation for particle creation by a Killing horizon using complex path analysis and using this we study particle creation in Schwarzschild-de Sitter spacetime by both black hole and the cosmological event horizons.
The signature of a black hole transit
NASA Technical Reports Server (NTRS)
Dolan, Joseph F.
1989-01-01
This paper considers the possibility of identifying a black hole on the basis of the detection of some unique effect occurring during the transit of a black hole across the stellar disk of a companion star in a binary system. The results of Monte-Carlo calculations show that the amplitude of the photometric and polarimetric light curves in a typical X-ray binary is too small to be observed with present instrumentation, but that a black hole transit might be detectable in a binary having a large separation of the components. No binary system suggested as containing a stellar-mass-sized black hole is a like candidate to exhibit an observable transit signature, with the possible exception of X Persei/4U0352+30 described by White et al. (1976).
Interior of a charged distorted black hole
Abdolrahimi, Shohreh; Frolov, Valeri P.; Shoom, Andrey A.
2009-07-15
We study the interior of a charged, nonrotating distorted black hole. We consider static and axisymmetric black holes, and focus on a special case when an electrically charged distorted solution is obtained by the Harrison-Ernst transformation from an uncharged one. We demonstrate that the Cauchy horizon of such a black hole remains regular, provided the distortion is regular at the event horizon. The shape and the inner geometry of both the outer and inner (Cauchy) horizons are studied. We demonstrate that there exists a duality between the properties of the horizons. Proper time of a free fall of a test particle moving in the interior of the distorted black hole along the symmetry axis is calculated. We also study the property of the curvature in the inner domain between the horizons. Simple relations between the 4D curvature invariants and the Gaussian curvature of the outer and inner horizon surfaces are found.
Merging Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2009-01-01
This talk will focus on simulations of binary black hole mergers and the gravitational wave signals they produce. Applications to gravitational wave detection with LISA, and electronagnetic counterparts, will be highlighted.
Charged fermions tunneling from regular black holes
Sharif, M. Javed, W.
2012-11-15
We study Hawking radiation of charged fermions as a tunneling process from charged regular black holes, i.e., the Bardeen and ABGB black holes. For this purpose, we apply the semiclassical WKB approximation to the general covariant Dirac equation for charged particles and evaluate the tunneling probabilities. We recover the Hawking temperature corresponding to these charged regular black holes. Further, we consider the back-reaction effects of the emitted spin particles from black holes and calculate their corresponding quantum corrections to the radiation spectrum. We find that this radiation spectrum is not purely thermal due to the energy and charge conservation but has some corrections. In the absence of charge, e = 0, our results are consistent with those already present in the literature.
Black Hole Entropy and the Renormalization Group
NASA Astrophysics Data System (ADS)
Satz, Alejandro; Jacobson, Ted
2015-01-01
Four decades after its first postulation by Bekenstein, black hole entropy remains mysterious. It has long been suggested that the entanglement entropy of quantum fields on the black hole gravitational background should represent at least an important contribution to the total Bekenstein-Hawking entropy, and that the divergences in the entanglement entropy should be absorbed in the renormalization of the gravitational couplings. In this talk, we describe how an improved understanding of black hole entropy is obtained by combining these notions with the renormalization group. By introducing an RG flow scale, we investigate whether the total entropy of the black hole can be partitioned in a "gravitational" part related to the flowing gravitational action, and a "quantum" part related to the unintegrated degrees of freedom. We describe the realization of this idea for free fields, and the complications and qualifications arising for interacting fields.
The 'Heartbeats' of Flaring Black Holes
This animation compares the X-ray 'heartbeats' of GRS 1915 and IGR J17091, two black holes that ingest gas from companion stars. GRS 1915 has nearly five times the mass of IGR J17091, which at thre...
Mass of a black hole firewall.
Abramowicz, M A; Kluźniak, W; Lasota, J-P
2014-03-07
Quantum entanglement of Hawking radiation has been supposed to give rise to a Planck density "firewall" near the event horizon of old black holes. We show that Planck density firewalls are excluded by Einstein's equations for black holes of mass exceeding the Planck mass. We find an upper limit of 1/(8πM) to the surface density of a firewall in a Schwarzschild black hole of mass M, translating for astrophysical black holes into a firewall density smaller than the Planck density by more than 30 orders of magnitude. A strict upper limit on the firewall density is given by the Planck density times the ratio M(Pl)/(8πM).
Black hole evaporation rates without spacetime.
Braunstein, Samuel L; Patra, Manas K
2011-08-12
Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobson's 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem.
Spectral line broadening in magnetized black holes
Frolov, Valeri P.; Shoom, Andrey A.; Tzounis, Christos E-mail: ashoom@ualberta.ca
2014-07-01
We consider weakly magnetized non-rotating black holes. In the presence of a regular magnetic field the motion of charged particles in the vicinity of a black hole is modified. As a result, the position of the innermost stable circular orbit (ISCO) becomes closer to the horizon. When the Lorentz force is repulsive (directed from the black hole) the ISCO radius can reach the gravitational radius. In the process of accretion charged particles (ions) of the accreting matter can be accumulated near their ISCO, while neutral particles fall down to the black hole after they reach 6M radius. The sharp spectral line Fe α, emitted by iron ions at such orbits, is broadened when the emission is registered by a distant observer. In this paper we study this broadening effect and discuss how one can extract information concerning the strength of the magnetic field from the observed spectrum.
CFT duals for accelerating black holes
NASA Astrophysics Data System (ADS)
Astorino, Marco
2016-09-01
The near horizon geometry of the rotating C-metric, describing accelerating Kerr-Newman black holes, is analysed. It is shown that, at extremality, even though it is not isomorphic to the extremal Kerr-Newman, it remains a warped and twisted product of AdS2 ×S2. Therefore the methods of the Kerr/CFT correspondence can successfully be applied to build a CFT dual model, whose entropy reproduces, through the Cardy formula, the Bekenstein-Hawking entropy of the accelerating black hole. The mass of accelerating Kerr-Newman black hole, which fulfils the first law of thermodynamics, is presented. Further generalisation in presence of an external Melvin-like magnetic field, used to regularise the conical singularity characteristic of the C-metrics, shows that the Kerr/CFT correspondence can be applied also for the accelerating and magnetised extremal black holes.
Reversible-process black hole thermodynamics
NASA Astrophysics Data System (ADS)
Chen, Liang-fan; Zhou, Min-yao
1984-03-01
Bekenstein, Hawking, Gibbons and Perry have discussed the case of placing a Schwarzschild black hole inside an ideal, reflecting box, thereby setting up an equilibrium state. In this paper, we discuss more generally the thennodynamical properties of such a system. Starting from adiabatic expansion of the system, we are naturally led to the definition of total entropy and of black hole entropy. We next point out the two conditions for stable equilibrium between the black hole and the radiation, V < VE and Er < M/4 are not equivalent: only the former is necessary and sufficient. Lastly, we examine three quasi-static processes of evaporation of the black hole, expansion at constant energy, energy release at constant volume and adiabatic expansion.
Gravitational radiation from extreme Kerr black hole
NASA Technical Reports Server (NTRS)
Sasaki, Misao; Nakamura, Takashi
1989-01-01
Gravitational radiation induced by a test particle falling into an extreme Kerr black hole was investigated analytically. Assuming the radiation is dominated by the infinite sequence of quasi-normal modes which has the limiting frequency m/(2M), where m is an azimuthal eigenvalue and M is the mass of the black hole, it was found that the radiated energy diverges logarithmically in time. Then the back reaction to the black hole was evaluated by appealing to the energy and angular momentum conservation laws. It was found that the radiation has a tendency to increase the ratio of the angular momentum to mass of the black hole, which is completely different from non-extreme case, while the contribution of the test particle is to decrease it.
Charged dilatonic black holes in gravity's rainbow
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Faizal, Mir; Panah, B. Eslam; Panahiyan, S.
2016-05-01
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.
White Dwarfs, Neutron Stars and Black Holes
ERIC Educational Resources Information Center
Szekeres, P.
1977-01-01
The three possible fates of burned-out stars: white dwarfs, neutron stars and black holes, are described in elementary terms. Characteristics of these celestial bodies, as provided by Einstein's work, are described. (CP)
Merging Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2009-01-01
This talk will focus on simulations of binary black hole mergers and the gravitational wave signals they produce. Applications to gravitational wave detection with LISA, and electronagnetic counterparts, will be highlighted.
Black Hole Spills Kaleidoscope of Color
2006-07-21
This new false-colored image from NASA Hubble, Chandra and Spitzer space telescopes shows a giant jet of particles that has been shot out from the vicinity of a type of supermassive black hole called a quasar.
Spherical boson stars as black hole mimickers
Guzman, F. S.; Rueda-Becerril, J. M.
2009-10-15
We present spherically symmetric boson stars as black hole mimickers based on the power spectrum of a simple accretion disk model. The free parameters of the boson star are the mass of the boson and the fourth-order self-interaction coefficient in the scalar field potential. We show that even if the mass of the boson is the only free parameter, it is possible to find a configuration that mimics the power spectrum of the disk due to a black hole of the same mass. We also show that for each value of the self-interaction a single boson star configuration can mimic a black hole at very different astrophysical scales in terms of the mass of the object and the accretion rate. In order to show that it is possible to distinguish one of our mimickers from a black hole, we also study the deflection of light.
NASA Astrophysics Data System (ADS)
Abramowicz, M. A.; Kluźniak, W.; Lasota, J.-P.
2014-03-01
Quantum entanglement of Hawking radiation has been supposed to give rise to a Planck density "firewall" near the event horizon of old black holes. We show that Planck density firewalls are excluded by Einstein's equations for black holes of mass exceeding the Planck mass. We find an upper limit of 1/(8πM) to the surface density of a firewall in a Schwarzschild black hole of mass M, translating for astrophysical black holes into a firewall density smaller than the Planck density by more than 30 orders of magnitude. A strict upper limit on the firewall density is given by the Planck density times the ratio MPl/(8πM).
Improved black hole fireworks: Asymmetric black-hole-to-white-hole tunneling scenario
NASA Astrophysics Data System (ADS)
De Lorenzo, Tommaso; Perez, Alejandro
2016-06-01
A new scenario for gravitational collapse has been recently proposed by Haggard and Rovelli. Presenting the model under the name of black hole fireworks, they claim that the accumulation of quantum gravitational effects outside the horizon can cause the tunneling of geometry from a black hole to a white hole, allowing a bounce of the collapsing star which can eventually go back to infinity. In this paper, we discuss the instabilities of this model and propose a simple minimal modification which eliminates them, as well as other related instabilities discussed in the literature. The new scenario is a time-asymmetric version of the original model with a time scale for the final explosion that is shorter than m log m in Planck units. Our analysis highlights the importance of irreversibility in gravitational collapse which, in turn, uncovers important issues that cannot be addressed in detail without a full quantum gravity treatment.