Rotating Black Holes and Coriolis Effect
Wu, Xiaoning; Yuan, Pei-Hung; Cho, Chia-Jui
2015-01-01
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the Petrov-like boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
Quantum effects near the black hole singularity
International Nuclear Information System (INIS)
We examine here the evolution of quantum effects near the spacetime singularity for a black hole spacetime. These are governed by a non-linear differential equation which is analysed to show that the quantum effects diverge near the singularity. This allows for the possibility that black holes without singularities might occur in nature. (author)
Effective Potential in Noncommutative BTZ Black Hole
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.
Nonthermal effect of dilatonic black holes
Institute of Scientific and Technical Information of China (English)
Lü Jun-Li
2005-01-01
The quantum nonthermal effect of the spherically symmetric and rotating dilatonic black holes is studied. A crossing of the positive and negative Dirac energy of particles occurs near dilatonic black holes. We find that the dilaton coupling parameter α affects the energy of spontaneous radiant particles. The energy of particles decreases when the coupling parameter α increases.
Minimum length effects in black hole physics
Casadio, Roberto; Nicolini, Piero
2014-01-01
We review the main consequences of the possible existence of a minimum measurable length, of the order of the Planck scale, on quantum effects occurring in black hole physics. In particular, we focus on the ensuing minimum mass for black holes and how modified dispersion relations affect the Hawking decay, both in four space-time dimensions and in models with extra spatial dimensions. In the latter case, we briefly discuss possible phenomenological signatures.
QCD and spin effects in black hole airshowers
Cavaglia, Marco; Roy, Arunava
2007-01-01
In models with large extra dimensions, black holes may be produced in high-energy particle collisions. We revisit the physics of black hole formation in extensive airshowers from ultrahigh-energy cosmic rays, focusing on collisional QCD and black hole emissivity effects. New results for rotating black holes are presented. Monte Carlo simulations show that QCD effects and black hole spin produce no observable signatures in airshowers. These results further confirm that the main characteristics...
Possible Effects of a Cosmological Constant on Black Hole Evolution
Adams, Fred C.; Mbonye, Manasse; Laughlin, Gregory
1999-01-01
We explore possible effects of vacuum energy on the evolution of black holes. If the universe contains a cosmological constant, and if black holes can absorb energy from the vacuum, then black hole evaporation could be greatly suppressed. For the magnitude of the cosmological constant suggested by current observations, black holes larger than $\\sim 4 \\times 10^{24}$ g would accrete energy rather than evaporate. In this scenario, all stellar and supermassive black holes would grow with time un...
Spacetime noncommutative effect on black hole as particle accelerators
Ding, Chikun; Liu, Changqing; Qian GUO
2013-01-01
We study the spacetime noncommutative effect on black hole as particle accelerators and, find that particle falling from infinity with zero velocity cannot collide with unbound energy when the noncommutative Kerr black hole is exactly extremal. Our results also show that the bigger of the spinning black hole's mass is, the higher of center of mass energy that the particles obtain. For small and medium noncommutative Schwarzschild black hole, the collision energy depends on the black holes' mass.
Effective Field Theoretical Approach to Black Hole Production
Bilke, Sven; Lipartia, Edisher; Maul, Martin
2002-01-01
A field theoretical description of mini black hole production at TeV energies is given taking into account the quantization of black holes in discrete resonances. The unknown quantum gravitational effects are absorbed in effective couplings, black hole masses and the Hawking temperature. The evaporation is described in terms of thermal field theory.
Spacetime Noncommutative Effect on Black Hole as Particle Accelerators
Ding, Chikun; Liu, Changqing; Quo, Qian
2013-03-01
We study the spacetime noncommutative effect on black hole as particle accelerators and, find that the particles falling from infinity with zero velocity cannot collide with unbound energy, either near the horizon or on the prograde ISCO when the noncommutative Kerr black hole is exactly extremal. Our results also show that the bigger of the spinning black hole's mass is the higher of center of mass energy that the particles obtain. For small and medium noncommutative Schwarzschild black hole, the collision energy depends on the black hole's mass.
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.
Relativistic quantum measurements, Unruh effect and black holes
International Nuclear Information System (INIS)
It is shown how to use method of limited path integrals or quantum passages for analysis of relativistic measurements. After that this method is used in order to clear physical nature of thermal effects observed by accelerated observer in Minkowski space-time (Unruh effect) and by far observer in black hole field (Hoking effect). Physical nature of thermal atmosphere around observer is analyzed in three cases: a) Unruh effect, b) perpetual (Schwarzschild) black hole and c) black hole, produced in collapse process
Holographic effective actions from black holes
International Nuclear Information System (INIS)
Using the Wald's relation between the Noether charge of diffeomorphisms and the entropy for a generic spacetime possessing a bifurcation surface, we introduce a method to obtain a family of higher order derivatives effective actions from the entropy of black holes. We consider the entropy as the starting point and we analyze the procedure of derivation of the action functional. We specialize to a particular class of theories which simplifies the calculations, f(R) theories. We apply the procedure to loop quantum gravity and to a general class of log-corrected entropy formulas.
Effective Stringy Description of Schwarzschild Black Holes
Krasnov, K V; Krasnov, Kirill; Solodukhin, Sergey N.
2004-01-01
We start by pointing out that certain Riemann surfaces appear rather naturally in the context of wave equations in the black hole background. For a given black hole there are two closely related surfaces. One is the Riemann surface of complexified ``tortoise'' coordinate. The other Riemann surface appears when the radial wave equation is interpreted as the Fuchsian differential equation. We study these surfaces in detail for the BTZ and Schwarzschild black holes in four and higher dimensions. Topologically, in all cases both surfaces are a sphere with a set of marked points; for BTZ and 4D Schwarzschild black holes there is 3 marked points. In certain limits the surfaces can be characterized very explicitly. We then show how properties of the wave equation (quasi-normal modes) in such limits are encoded in the geometry of the corresponding surfaces. In particular, for the Schwarzschild black hole in the high damping limit we describe the Riemann surface in question and use this to derive the quasi-normal mode...
Quantum Gravity Effects in Black Holes at the LHC
Alberghi, Gian Luigi; Casadio, Roberto(Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, Bologna, 40126, Italy); Tronconi, Alessandro
2006-01-01
We study possible back-reaction and quantum gravity effects in the evaporation of black holes which could be produced at the LHC through a modification of the Hawking emission. The corrections are phenomenologically taken into account by employing a modified relation between the black hole mass and temperature. The usual assumption that black holes explode around $1 $TeV is also released, and the evaporation process is extended to (possibly much) smaller final masses. We show that these effec...
Effects of quintessence on thermodynamics of the black holes
Ghaderi, K.; Malakolkalami, B.
2016-05-01
In this letter, we investigate the effects of quintessence on thermodynamics of the Bardeen black hole and compare them with the results of our former paper. Black hole thermodynamic stability can be determined by studying the nature of heat capacity of the system. We use the first-law of thermodynamics to derive the thermodynamic quantities of these black holes and we compare and analyse the results. We plot the variation of mass, temperature and heat capacity as a functions of entropy related to the quintessence. Finally, we study the equation of state of these black holes with quintessence.
Effects of Noncommutativity on the Black Hole Entropy
Gupta, Kumar S; Juric, Tajron; Meljanac, Stjepan; Samsarov, Andjelo
2013-01-01
In this paper the BTZ black hole geometry is probed with a noncommutative scalar field which obeys the $\\kappa$-Minkowski algebra. The entropy of the BTZ black hole is calculated using the brick wall method. The contribution of the noncommutativity to the black hole entropy is explicitly evaluated up to the first order in the deformation parameter. We also argue that such a correction to the black hole entropy can be interpreted as arising from the renormalization of the Newton's constant due to the effects of the noncommutativity.
Effects of Noncommutativity on the Black Hole Entropy
International Nuclear Information System (INIS)
The BTZ black hole geometry is probed with a noncommutative scalar field which obeys the κ-Minkowski algebra. The entropy of the BTZ black hole is calculated using the brick wall method. The contribution of the noncommutativity to the black hole entropy is explicitly evaluated up to the first order in the deformation parameter. We also argue that such a correction to the black hole entropy can be interpreted as arising from the renormalization of the Newton’s constant due to the effects of the noncommutativity
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Mu, Benrong; Yang, Haitang
2015-01-01
In this paper, we investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole's mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Effects of Noncommutativity on the Black Hole Entropy
Directory of Open Access Journals (Sweden)
Kumar S. Gupta
2014-01-01
Full Text Available The BTZ black hole geometry is probed with a noncommutative scalar field which obeys the κ-Minkowski algebra. The entropy of the BTZ black hole is calculated using the brick wall method. The contribution of the noncommutativity to the black hole entropy is explicitly evaluated up to the first order in the deformation parameter. We also argue that such a correction to the black hole entropy can be interpreted as arising from the renormalization of the Newton’s constant due to the effects of the noncommutativity.
Binary black holes' effects on electromagnetic fields.
Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David
2009-08-21
In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves. PMID:19792706
Black holes and the butterfly effect
International Nuclear Information System (INIS)
We use holography to study sensitive dependence on initial conditions in strongly coupled field theories. Specifically, we mildly perturb a thermofield double state by adding a small number of quanta on one side. If these quanta are released a scrambling time in the past, they destroy the local two-sided correlations present in the unperturbed state. The corresponding bulk geometry is a two-sided AdS black hole, and the key effect is the blueshift of the early infalling quanta relative to the t=0 slice, creating a shock wave. We comment on string- and Planck-scale corrections to this setup, and discuss points that may be relevant to the firewall controversy
Black holes and the butterfly effect
Shenker, Stephen H
2013-01-01
We use holography to study sensitive dependence on initial conditions in strongly coupled field theories. Specifically, we mildly perturb a thermofield double state by adding a small number of quanta on one side. If these quanta are released a scrambling time in the past, they destroy the local two-sided correlations present in the unperturbed state. The corresponding bulk geometry is a two-sided AdS black hole, and the key effect is the blueshift of the early infalling quanta relative to the $t = 0$ slice, creating a shock wave. We comment on string- and Planck-scale corrections to this setup, and discuss points that may be relevant to the firewall controversy.
Quantum Gravity Effects On Charged Micro Black Holes Thermodynamics
Abbasvandi, N; Radiman, Shahidan; Abdullah, W A T Wan
2016-01-01
The charged black hole thermodynamics is corrected in terms of the quantum gravity effects. Most of the quantum gravity theories support the idea that near the Planck scale, the standard Heisenberg uncertainty principle should be reformulated by the so-called Generalized Uncertainty Principle (GUP) which provides a perturbation framework to perform required modifications of the black hole quantities. In this paper, we consider the effects of the minimal length and maximal momentum as GUP type I and the minimal length, minimal momentum, and maximal momentum as GUP type II on thermodynamics of the charged TeV-scale black holes. We also generalized our study to the universe with the extra dimensions based on the ADD model. In this framework, the effect of the electrical charge on thermodynamics of the black hole and existence of the charged black hole remnants as a potential candidate for the dark matter particles are discussed.
Quantum gravity effects in black holes at the LHC
International Nuclear Information System (INIS)
We study possible back-reaction and quantum gravity effects in the evaporation of black holes which could be produced at the LHC through a modification of the Hawking emission. The corrections are phenomenologically taken into account by employing a modified relation between the black hole mass and temperature. The usual assumption that black holes explode around 1 TeV is also released, and the evaporation process is extended to (possibly much) smaller final masses. We show that these effects could be observable for black holes produced with a relatively large mass and should therefore be taken into account when simulating micro-black hole events for the experiments planned at the LHC
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Directory of Open Access Journals (Sweden)
Benrong Mu
2015-01-01
Full Text Available We investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole’s mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
International Nuclear Information System (INIS)
We investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole’s mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time
Tunnelling Effect and Hawking Radiation from a Vaidya Black Hole
Institute of Scientific and Technical Information of China (English)
ZHANG Jing-Yi; ZHAO Zheng
2006-01-01
@@ We extend Parikh's study to the non-stationary black hole. As an example of the non-stationary black hole, we investigate the tunnelling effect and Hawking radiation from a Vaidya black hole whose Bondi mass is identical to its mass parameter. The Hawking radiation is considered as a tunnelling process across the event horizon and we calculate the tunnelling probability. It is found that the result is different from Parikh's study because drH/dv is the function of Bondi mass m(v).
Black Hole Remnants in Hayward Solutions and Noncommutative Effects
Mehdipour, S. H.; Ahmadi, M. H.
2016-01-01
In this paper, we explore the final stages of the black hole evaporation for Hayward solutions. Our results show that the behavior of Hawking's radiation changes considerably at the small radii regime such that the black hole does not evaporate completely and a stable remnant is left. We analyse the effect that an inspired model of the noncommutativity of spacetime can have on the thermodynamics of Hayward spacetimes. This has been done by applying the noncommutative effects to the non-rotati...
Quantum Gravity Effects On Charged Micro Black Holes Thermodynamics
Abbasvandi, N.; Soleimani, M. J.; Radiman, Shahidan; Abdullah, W. A. T. Wan
2016-01-01
The charged black hole thermodynamics is corrected in terms of the quantum gravity effects. Most of the quantum gravity theories support the idea that near the Planck scale, the standard Heisenberg uncertainty principle should be reformulated by the so-called Generalized Uncertainty Principle (GUP) which provides a perturbation framework to perform required modifications of the black hole quantities. In this paper, we consider the effects of the minimal length and maximal momentum as GUP type...
Effects of black hole evaporation on the quantum entangled state
International Nuclear Information System (INIS)
We investigate the effect of black hole evaporation on the entangled state in which one party of a pair, Alice, falls into the black hole at formation while the other party, Bob, remains outside the black hole. The final state of a black hole is studied by taking into account a general unitary evolution of a black-hole matter state. The mixedness is found to decrease under a general unitary transformation when the initial matter state is in a mixed state and the mean fidelity at the evaporation is smaller than the fidelity of the quantum teleportation by a factor of the inverse square of the number of states of a black hole. The change in the entanglement of the Alice-Bob pair at evaporation is studied by calculating the entanglement fidelity and eigenvalues of the partial transposed block density matrix. The entanglement fidelity is found to be inversely proportional to the square of the Hilbert space dimension N, and the entanglement could survive the evaporation process.
Effects of black hole evaporation on the quantum entangled state
Energy Technology Data Exchange (ETDEWEB)
Ahn, Doyeol [University of Seoul, Seoul (Korea, Republic of)
2010-10-15
We investigate the effect of black hole evaporation on the entangled state in which one party of a pair, Alice, falls into the black hole at formation while the other party, Bob, remains outside the black hole. The final state of a black hole is studied by taking into account a general unitary evolution of a black-hole matter state. The mixedness is found to decrease under a general unitary transformation when the initial matter state is in a mixed state and the mean fidelity at the evaporation is smaller than the fidelity of the quantum teleportation by a factor of the inverse square of the number of states of a black hole. The change in the entanglement of the Alice-Bob pair at evaporation is studied by calculating the entanglement fidelity and eigenvalues of the partial transposed block density matrix. The entanglement fidelity is found to be inversely proportional to the square of the Hilbert space dimension N, and the entanglement could survive the evaporation process.
Topics in black hole evaporation
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Two major aspects of particle creation by gravitational fields of black holes are studied: the neutrino emission from rotating black holes; and interactions between scalar particles emitted by a black hole. Neutrino emission is investigated under three topics: The asymmetry of the angular dependence of neutrino emission from rotating black holes; the production of a local matter excess by rotating black holes in a baryon symmetric universe; and cosmological magnetic field generation by neutrinos from evaporating black holes. Finally the author studies the effects of interactions on the black hole evaporation process
Effect of vacuum polarization near black holes
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In this paper the authors describe the main of the obtained results. The authors hope that the part of them appears to be new. They use the sign conventions of Misner, Thorne and Wheeler and Planck's units: h-bar = c = G = 1. In the one-loop approximation the contributions of different physical fields to the vacuum polarization are additive. It is convenient to investigate the contributions of massive and massless fields separately using different methods. If the wavelength λ/sub m/ = h-bar/mc of a massive (with mass m) field is much smaller than the characteristic radius L of the spacetime curvature, then the contribution of this field to the vacuum polarization is essentially determined by the local properties of the geometry and it can be expanded in the series with respect to the small parameter E = (λ/sub m//L)/sup 2/. The contribution of massless field to the vacuum polarization is essentially nonlocal and its calculation is much more complicated because of the absence of any small parameters. It is rather surprising that for massless fields one can nevertheless develop rather good approximate analytic methods and obtain exact explicit expressions for quantities describing vacuum polarization near black holes
Gravitational Effects Near the Kerr-Newman Black Hole
Institute of Scientific and Technical Information of China (English)
王永久; 唐智明
2001-01-01
e have reached a solution of the Dirac equation and the energy spectrum of electrons in the gravitational field of the Kerr-Newman black hole. The results are interesting in astrophysics for observations of the black hole.
Effective photon mass from black-hole formation
Emelyanov, Slava
2016-01-01
We compute the value of effective photon mass $m_\\gamma$ at one-loop level in QED due to the formation of small spherically symmetric black hole in asymptotically flat spacetime. This effect is associated with the modification of electron/positron propagator during matter collapse. Physical manifestations of black-hole environment are compared with those of hot neutral plasma. We estimate the distance to the nearest black hole from the upper bound on $m_\\gamma$ obtained in the Coulomb-law test. We also find that corrections to electron mass $m_e$ and fine structure constant $\\alpha$ at one-loop level in QED are negligibly small in the weak gravity regime.
Effective action for the field equations of charged black holes
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We consistently reduce the equations of motion for the bosonic N = 2 supergravity action, using a multi-centered black hole ansatz for the metric. This reduction is done in a general, non-supersymmetric setup, in which we extend concepts of BPS black hole technology. First we obtain a more general form of the black hole potential, as part of an effective action for both the scalars and the vectors in the supergravity theory. Furthermore, we show that there are extra constraints specifying the solution, which we calculate explicitly. In the literature, these constraints have already been studied in the one-center case. We also show that the effective action we obtain for non-static metrics can be linked to the 'entropy function' for the spherically symmetric case, as defined by Sen (2005 J. High Energy Phys. JHEP09(2005)038) and Cardoso et al (2007 J. High Energy Phys. JHEP03(2007)085)
Effects of Noncommutativity on the Black Hole Entropy
Gupta, Kumar S.(Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India); Harikumar, E.; Tajron Jurić; Stjepan Meljanac; Andjelo Samsarov
2013-01-01
In this paper the BTZ black hole geometry is probed with a noncommutative scalar field which obeys the $\\kappa$-Minkowski algebra. The entropy of the BTZ black hole is calculated using the brick wall method. The contribution of the noncommutativity to the black hole entropy is explicitly evaluated up to the first order in the deformation parameter. We also argue that such a correction to the black hole entropy can be interpreted as arising from the renormalization of the Newton's constant due...
Andersson, N
2000-01-01
This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.
Effect of spins on the quantum entropy of black holes
Jing, Jiliang; Yan, Mu-Lin
2000-01-01
By using the Newman-Penrose formalism and 't Hooft brick-wall model, the quantum entropies of the Kerr-Newman black hole due to the Dirac and electromagnetic fields are calculated and the effects of the spins of the photons and Dirac particles on the entropies are investigated. It is shown that the entropies depend only on the square of the spins of the particles and the contribution of the spins is dependent on the rotation of the black hole, except that different fields obey different stati...
Relativistic Effects Around Black Holes: Smearing Absorption Edges
Zhang, X. L.; Feng, Y. X.; Zhang, S. N.; Yao, Y.
2002-01-01
Broad iron absorption structures have been observed in the X-ray spectra of both AGNs and black hole X-ray binaries (BHXBs). A correctly modeled absorption structure can reveal the physical condition of the source, help to determine the continuum spectra and thus help to estimate other spectral lifes more accurately. The absorption structures are usually thought to be caused by the reflection of X-rays by the accretion disks around the central black holes, and the broadening can be a ttributed to the ionization states of the disk and relativistic effects.
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's research councils have yet to put any real money behind these ideas. Black holes are best described by the general theory of relativity. However, general relativity is a classical theory of gravity, and although its predictions have been verified in many experiments, a quantum theory of gravity remains one of the holy grails of physics. One of the first physicists to make real progress in this quest to reconcile general relativity and quantum mechanics was Stephen Hawking. In 1974 Hawking calculated what would happen if a quantum fluctuation occurred near an event horizon. He concluded that the black hole would radiate, and that the amount of radiation would be inversely proportional to the mass of the black hole. However, black holes tend to be very heavy, so their output of Hawking radiation would be too low to detect experimentally. One intriguing exception could be much smaller primordial black holes created in the big bang: these should radiate observable amounts of gamma rays, but they have not been detected yet. This whole body of work - in which thermodynamic concepts such as temperature and entropy are also associated with the black hole - is Hawking's major achievement in physics. The detection of Hawking radiation is the ultimate goal of experiments on artificial black holes, although a lot of theoretical and experimental work has to be done first. The successful experiment is likely to involve a flowing Bose-Einstein condensate or a medium in which the speed of light can be reduced to zero. After years of groundwork, physicists have recently made rapid progress in both these fields. Meanwhile, the recent observation of neutrons in discrete quantum states in a gravitational potential shows that quantum gravity effects can be seen in the laboratory. All that is needed now is an act of faith. (U.K.)
Fluctuating Black Hole Horizons
Mei, Jianwei
2013-01-01
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.
Spin polarization effects in micro black hole evaporation
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We consider the evaporation of rotating micro black holes produced in highly energetic particle collisions, taking into account the polarization due to the coupling between the spin of the emitted particles and the angular momentum of the black hole. The effect of rotation shows up in the helicity dependent angular distribution significantly. By using this effect, there is a possibility to determine the axis of rotation for each black hole formed, suggesting a way to improve the statistics. Deviation from thermal spectrum is also a signature of rotation. This deviation is due to the fact that rapidly rotating holes have an effective temperature Teff significantly higher than the Hawking temperature TH. The deformation of the spectral shape becomes evident only for very rapidly rotating cases. We show that, since the spectrum follows a blackbody profile with an effective temperature, it is difficult to determine both the number of extra-dimensions and the rotation parameter from the energy spectrum alone. We argue that the helicity dependent angular distribution may provide a way to resolve this degeneracy. We illustrate the above results for the case of fermions.
Tunnelling effect of the non-stationary Kerr black hole
Institute of Scientific and Technical Information of China (English)
Yang Shu-Zheng; Chen De-You
2008-01-01
Extending Parikh and Wilezek's work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilton-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein-Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole.
Tunnelling effect of the non-stationary Kerr black hole
Yang, Shu-Zheng; Chen, De-You
2008-03-01
Extending Parikh and Wilczek's work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilton-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein-Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole.
ULTRAMASSIVE BLACK HOLE COALESCENCE
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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
Quantum aspects of black holes
2015-01-01
Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.
Minimal length effects in black hole thermodynamics from tunneling formalism
Gangopadhyay, Sunandan
2016-01-01
The tunneling formalism in the Hamilton-Jacobi approach is adopted to study Hawking radiation of massless Dirac particles from spherically symmetric black hole spacetimes incorporating the effects of the generalized uncertainty principle. The Hawking temperature is found to contain corrections from the generalized uncertainty principle. An alternative derivation of this result is also presented which makes use of the tunneling result for the probability of the outgoing particle in the absence of quantum gravity effects. This approach is then exploited to compute the Hawking temperature for more general forms of the uncertainty principle having infinite number of terms. Choosing the coefficients of the terms in the series in a specific way enables one to sum the infinite series exactly. This leads to a Hawking temperature for the Schwarzschild black hole that agrees with the result which accounts for the one loop back reaction effect. The entropy is finally computed and yields the area theorem upto logarithmic...
Minimal Length Effects in Black Hole Thermodynamics from Tunneling Formalism
Gangopadhyay, Sunandan
2016-01-01
The tunneling formalism in the Hamilton-Jacobi approach is adopted to study Hawking radiation of massless Dirac particles from spherically symmetric black hole spacetimes incorporating the effects of the generalized uncertainty principle. The Hawking temperature is found to contain corrections from the generalized uncertainty principle. Further, we show from this result that the ratio of the GUP corrected energy of the particle to the GUP corrected Hawking temperature is equal to the ratio of the corresponding uncorrected quantities. This result is then exploited to compute the Hawking temperature for more general forms of the uncertainty principle having infinite number of terms. Choosing the coefficients of the terms in the series in a specific way enables one to sum the infinite series exactly. This leads to a Hawking temperature for the Schwarzschild black hole that agrees with the result which accounts for the one loop back reaction effect. The entropy is finally computed and yields the area theorem upto logarithmic corrections.
Black Hole Remnants in Hayward Solutions and Noncommutative Effects
Mehdipour, S H
2016-01-01
In this paper, we explore the final stages of the black hole evaporation for Hayward solutions. Our results show that the behavior of Hawking's radiation changes considerably at the small radii regime such that the black hole do not evaporate completely and a stable remnant is left. We analyse the effect that an inspired model of the noncommutativity of spacetime can have on the thermodynamics of Hayward spacetimes. This has been done by applying the noncommutative effects to the non-rotating and rotating Hayward black holes. In this setup, all point structures get replaced by smeared distributions owing to this inspired approach. The noncommutative effects result in a colder BH in the small radii regime as Hayward's free parameter $g$ increases. As well as the effects of noncommutativity and the rotation factor, the configuration of the remnant can be substantially affected by the parameter $g$. However, in the rotating solution it is not so sensitive to $g$ with respect to the non-rotating case. As a conseq...
International Nuclear Information System (INIS)
We study noncommutative black holes, by using 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 Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole
Quantum effects near a charged black hole singularity
International Nuclear Information System (INIS)
In this paper, the authors present an investigation of the problem of quantum fluctuations near a charged black hole singularity. The authors show that quantum fluctuations do not vanish near the singularity leading to the conclusion that charged black hole singularities are unlikely to occur in nature. This result may be obvious but we derive it here
Spacetime Duality of BTZ Black Hole
Ho, Jeongwon; Kim, Won T.; Park, Young-Jai
1999-01-01
We consider the duality of the quasilocal black hole thermodynamics, explicitly the quasilocal black hole thermodynamic first law, in BTZ black hole solution as a special one of the three-dimensional low energy effective string theory.
Are black holes totally black?
Grib, A A
2014-01-01
Geodesic completeness needs existence near the horizon of the black hole of "white hole" geodesics coming from the region inside of the horizon. Here we give the classification of all such geodesics with the energies $E/m \\le 1$ for the Schwarzschild and Kerr's black hole. The collisions of particles moving along the "white hole" geodesics with those moving along "black hole" geodesics are considered. Formulas for the increase of the energy of collision in the centre of mass frame are obtained and the possibility of observation of high energy particles arriving from the black hole to the Earth is discussed.
Superluminality, Black Holes and Effective Field Theory
Goon, Garrett
2016-01-01
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-per...
Dumb Holes and the Effects of High Frequencies on Black Hole Evaporation
Unruh, W. G.
1994-01-01
The naive calculation of black hole evaporation makes the thermal emission depend on the arbitrary high frequency behaviour of the theory where the theory is certainly wrong. Using the sonic analog to black holes-- dumb holes-- I show numerically that a change in the dispersion relation at high frequencies does not seem to alter the evaporation process, lending weight to the reality of the black hole evaporation process. I also suggest a reason for the insensitivity of the process to high fre...
Effects of cosmic acceleration on black hole thermodynamics
Mandal, Abhijit
2016-07-01
Direct local impacts of cosmic acceleration upon a black hole are matters of interest. Babichev et. al. had published before that the Friedmann equations which are prevailing the part of fluid filled up in the universe to lead (or to be very specific, `dominate') the other constituents of universe and are forcing the universe to undergo present-day accelerating phase (or to lead to violate the strong energy condition and latter the week energy condition), will themselves tell that the rate of change of mass of the central black hole due to such exotic fluid's accretion will essentially shrink the mass of the black hole. But this is a global impact indeed. The local changes in the space time geometry next to the black hole can be analysed from a modified metric governing the surrounding space time of a black hole. A charged deSitter black hole solution encircled by quintessence field is chosen for this purpose. Different thermodynamic parameters are analysed for different values of quintessence equation of state parameter, ω_q. Specific jumps in the nature of the thermodynamic space near to the quintessence or phantom barrier are noted and physically interpreted as far as possible. Nature of phase transitions and the situations at which these transitions are taking place are also explored. It is determined that before quintessence starts to work (ω_q=-0.33>-1/3) it was preferable to have a small unstable black hole followed by a large stable one. But in quintessence (-1/3>ω_q>-1), black holes are destined to be unstable large ones pre-quelled by stable/ unstable small/ intermediate mass black holes.
Effects of nonzero neutrino masses on black hole evaporation
International Nuclear Information System (INIS)
We study the consequences of nonzero neutrino masses for black holes evaporating by the emission of Hawking radiation. We find that the evolution of small, hot, black holes may be unaffected (if neutrinos are Majorana particles) or may show an increase in neutrino luminosity and a decrease in lifetime by up to a factor of 1.85 (if neutrinos are Dirac particles). However, for sufficiently large (e.g., stellar mass) black holes, neutrino emission is largely or entirely suppressed, resulting in a decrease in emitted power and an increase in lifetime by up to a factor of 7.5
Deceleration Effect of Magnetic Field on Black Hole Accretion Disks
Institute of Scientific and Technical Information of China (English)
WANG Ding-Xiong
2000-01-01
The deceleration effect of magnetic field near the horizon of a spinning black hole (BH) of accretion disk is investigated in the Blandford-Znajek (BZ) process. It is shown that rates of change with respect to time for both the angular velocities of BH horizon and accreting particles at the inner edge of an accretion disk are reduced in the BZ process, behaving with non-monotonous evolution characteristics. This result implies that the magnetic field near the BH horizon has & deceleration effect not only on the spinning BH but also on the surrounding accretion disk.
International Nuclear Information System (INIS)
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: ► The information paradox is a serious problem. ► To solve it we need to find ‘hair’ on black holes. ► In string theory we find ‘hair’ by the fuzzball construction. ► Fuzzballs help to resolve many other issues in gravity.
Energy Technology Data Exchange (ETDEWEB)
NONE
2002-02-01
instance, the UK's research councils have yet to put any real money behind these ideas. Black holes are best described by the general theory of relativity. However, general relativity is a classical theory of gravity, and although its predictions have been verified in many experiments, a quantum theory of gravity remains one of the holy grails of physics. One of the first physicists to make real progress in this quest to reconcile general relativity and quantum mechanics was Stephen Hawking. In 1974 Hawking calculated what would happen if a quantum fluctuation occurred near an event horizon. He concluded that the black hole would radiate, and that the amount of radiation would be inversely proportional to the mass of the black hole. However, black holes tend to be very heavy, so their output of Hawking radiation would be too low to detect experimentally. One intriguing exception could be much smaller primordial black holes created in the big bang: these should radiate observable amounts of gamma rays, but they have not been detected yet. This whole body of work - in which thermodynamic concepts such as temperature and entropy are also associated with the black hole - is Hawking's major achievement in physics. The detection of Hawking radiation is the ultimate goal of experiments on artificial black holes, although a lot of theoretical and experimental work has to be done first. The successful experiment is likely to involve a flowing Bose-Einstein condensate or a medium in which the speed of light can be reduced to zero. After years of groundwork, physicists have recently made rapid progress in both these fields. Meanwhile, the recent observation of neutrons in discrete quantum states in a gravitational potential shows that quantum gravity effects can be seen in the laboratory. All that is needed now is an act of faith. (U.K.)
Noncommutative Effects in the Black Hole Evaporation in Two Dimensions
Garcia-Compean, Hugo; Soto-Campos, Carlos
2006-01-01
We discuss some possible implications of a two-dimensional toy model for black hole evaporation in noncommutative field theory. While the noncommutativity we consider does not affect gravity, it can play an important role in the dynamics of massless and Hermitian scalar fields in the event horizon of a Schwarzschild black hole. We find that noncommutativity will affect the flux of outgoing particles and the nature of its UV/IR divergences. Moreover, we show that the noncommutative interaction...
Noncommutative black hole thermodynamics
International Nuclear Information System (INIS)
We give a general derivation, for any static spherically symmetric metric, of the relation Th=(K/2π) connecting the black hole temperature (Th) 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
Nonstationary analogue black holes
International Nuclear Information System (INIS)
We study the existence of analogue nonstationary spherically symmetric black holes. The prime example is the acoustic model see Unruh (1981 Phys. Rev. Lett. 46 1351). We consider also a more general class of metrics that could be useful in other physical models of analogue black and white holes. We give examples of the appearance of black holes and of disappearance of white holes. We also discuss the relation between the apparent and the event horizons for the case of analogue black holes. In the end we study the inverse problem of determination of black or white holes by boundary measurements for the spherically symmetric nonstationary metrics. (paper)
Hayward, Sean A.
2008-01-01
This is a review of current theory of black-hole dynamics, concentrating on the framework in terms of trapping horizons. Summaries are given of the history, the classical theory of black holes, the defining ideas of dynamical black holes, the basic laws, conservation laws for energy and angular momentum, other physical quantities and the limit of local equilibrium. Some new material concerns how processes such as black-hole evaporation and coalescence might be described by a single trapping h...
Energy Technology Data Exchange (ETDEWEB)
Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)
2007-11-15
We study noncommutative black holes, by using 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 Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.
Strominger, Andrew
1993-01-01
The quantum statistics of charged, extremal black holes is investigated beginning with the hypothesis that the quantum state is a functional on the space of closed three-geometries, with each black hole connected to an oppositely charged black hole through a spatial wormhole. From this starting point a simple argument is given that a collection of extremal black holes obeys neither Bose nor Fermi statistics. Rather they obey an exotic variety of particle statistics known as ``infinite statist...
Gao, C. J.; Zhang, S. N.
2006-01-01
The exact solutions of electrically charged phantom black holes with the cosmological constant are constructed. They are labelled by the mass, the electrical charge, the cosmological constant and the coupling constant between the phantom and the Maxwell field. It is found that the phantom has important consequences on the properties of black holes. In particular, the extremal charged phantom black holes can never be achieved and so the third law of thermodynamics for black holes still holds. ...
Testing quantum gravity effects through Dyonic charged AdS black hole
Sadeghi, J.; Pourhassan, B.; Rostami, M.
2016-01-01
In this paper, we consider dyonic charged AdS black hole which is holographic dual of a van der Waals fluid. We use logarithmic corrected entropy and study thermodynamics of the black hole and show that holographic picture is still valid. Critical behaviors and stability also discussed. Logarithmic corrections arises due to thermal fluctuations which are important when size of black hole be small. So, thermal fluctuations interpreted as quantum effect. It means that we can see quantum effect ...
Noncommutative solitonic black hole
International Nuclear Information System (INIS)
We investigate solitonic black hole solutions in three-dimensional noncommutative spacetime. We do this in gravity with a negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value. (paper)
Noncommutative solitonic black hole
Chang-Young, Ee; Kimm, Kyoungtae; Lee, Daeho; Lee, Youngone
2012-05-01
We investigate solitonic black hole solutions in three-dimensional noncommutative spacetime. We do this in gravity with a negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value.
Visser, M
1999-01-01
Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.
Good, Michael R R
2014-01-01
A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. 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.
Dvali, Gia
2013-01-01
According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.
International Nuclear Information System (INIS)
According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers
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.
International Nuclear Information System (INIS)
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∞/(πc(ℎ/2π)), 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.
Tortoise coordinate and Hawking effect in a dynamical Kerr black hole
Yang, Jian; Zhao, Zheng; Liu, Wenbiao
2011-02-01
Hawking effect from a dynamical Kerr black hole is investigated using the improved Damour-Ruffini method with a new tortoise coordinate transformation. Hawking temperature of the black hole can be obtained point by point at the event horizon. It is found that Hawking temperatures of different points on the surface are different. Moreover, the temperature does not turn to zero while the dynamical black hole turns to an extreme one.
Tortoise coordinate and Hawking effect in a dynamical Kerr black hole
Yang, Jian
2010-01-01
Hawking effect from a dynamical Kerr black hole is investigated using the improved Damour-Ruffini method with a new tortoise coordinate transformation. Hawking temperature of the black hole can be obtained point by point at the event horizon. It is found that Hawking temperatures of different points on the surface are different. Moreover, the temperature does not turn to zero while the dynamical black hole turns to an extreme one.
Black Hole Masses are Quantized
Dvali, Gia; Mukhanov, Slava
2011-01-01
We give a simple argument showing that in any sensible quantum field theory the masses of black holes cannot assume continuous values and must be quantized. Our proof solely relies on Poincare-invariance of the asymptotic background, and is insensitive to geometric characteristics of black holes or other peculiarities of the short distance physics. Therefore, our results are equally-applicable to any other localized objects on asymptotically Poincare-invariant space, such as classicalons. By adding a requirement that in large mass limit the quantization must approximately account for classical results, we derive an universal quantization rule applicable to all classicalons (including black holes) in arbitrary number of dimensions. In particular, this implies, that black holes cannot emit/absorb arbitrarily soft quanta. The effect has phenomenological model-independent implications for black holes and other classicalons that may be created at LHC. We predict, that contrary to naive intuition, the black holes a...
Noncommutative effects in the black hole evaporation in two dimensions
International Nuclear Information System (INIS)
We discuss some possible implications of a two-dimensional toy model for black hole evaporation in noncommutative field theory. While the noncommutativity we consider does not affect gravity, it can play an important role in the dynamics of massless and Hermitian scalar fields in the event horizon of a Schwarzschild black hole. We find that noncommutativity will affect the flux of outgoing particles and the nature of its UV/IR divergences. Moreover, we show that the noncommutative interaction does not affect Leahy's and Unruh's interpretation of thermal ingoing and outgoing fluxes in the black hole evaporation process. Thus, the noncommutative interaction still destroys the thermal nature of fluxes. In the process, some nonlocal implications of the noncommutativity are discussed
Casimir Effect in 2D Stringy Black Hole Backgrounds
Christodoulakis, T; Georgalas, B C; Vagenas, E C
2001-01-01
We consider the two-dimensional "Schwarzschild" and "Reissner-Nordstrom" stringy black holes as systems of Casimir type. We explicitly calculate the energy-momentum tensor of a massless scalar field satisfying Dirichlet boundary conditions on two one-dimensional "walls". These results are obtained using the Wald's axioms. Thermodynamical quantities such as pressure, specific heat, isothermal compressibility and entropy of the two-dimensional stringy black holes are calculated. A comparison is made between the obtained results and the laws of thermodynamics. The results obtained for the extremal (Q=M) stringy two-dimensional charged black hole are identical in all three different vacua used; a fact that indicates its quantum stability.
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.
Black holes and the multiverse
Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun
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.
Energy Technology Data Exchange (ETDEWEB)
Bender, P. [Univ. of Colorado, Boulder, CO (United States); Bloom, E. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy] [and others
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.
Quantum Gravity effects near the null black hole singularity
Bonanno, Alfio; Reuter, Martin
1998-01-01
The structure of the Cauchy Horizon singularity of a black hole formed in a generic collapse is studied by means of a renormalization group equation for quantum gravity. It is shown that during the early evolution of the Cauchy Horizon the increase of the mass function is damped when quantum fluctuations of the metric are taken into account.
Stimulated Black Hole Evaporation
Spaans, Marco
2016-01-01
Black holes are extreme expressions of gravity. Their existence is predicted by Einstein's theory of general relativity and is supported by observations. Black holes obey quantum mechanics and evaporate spontaneously. Here it is shown that a mass rate $R_f\\sim 3\\times 10^{-8} (M_0/M)^{1/2}$ $M_0$ yr$^{-1}$ onto the horizon of a black hole with mass $M$ (in units of solar mass $M_0$) stimulates a black hole into rapid evaporation. Specifically, $\\sim 3 M_0$ black holes can emit a large fraction of their mass, and explode, in $M/R_f \\sim 3\\times 10^7 (M/M_0)^{3/2}$ yr. These stimulated black holes radiate a spectral line power $P \\sim 2\\times 10^{39} (M_0/M)^{1/2}$ erg s$^{-1}$, at a wavelength $\\lambda \\sim 3\\times 10^5 (M/M_0)$ cm. This prediction can be observationally verified.
Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica
2016-01-01
Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.
World-volume effective theory for higher-dimensional black holes.
Emparan, Roberto; Harmark, Troels; Niarchos, Vasilis; Obers, Niels A
2009-05-15
We argue that the main feature behind novel properties of higher-dimensional black holes, compared to four-dimensional ones, is that their horizons can have two characteristic lengths of very different size. We develop a long-distance world-volume effective theory that captures the black hole dynamics at scales much larger than the short scale. In this limit the black hole is regarded as a blackfold: a black brane (possibly boosted locally) whose world volume spans a curved submanifold of the spacetime. This approach reveals black objects with novel horizon geometries and topologies more complex than the black ring, but more generally it provides a new organizing framework for the dynamics of higher-dimensional black holes. PMID:19518938
World-Volume Effective Theory for Higher-Dimensional Black Holes
International Nuclear Information System (INIS)
We argue that the main feature behind novel properties of higher-dimensional black holes, compared to four-dimensional ones, is that their horizons can have two characteristic lengths of very different size. We develop a long-distance world-volume effective theory that captures the black hole dynamics at scales much larger than the short scale. In this limit the black hole is regarded as a blackfold: a black brane (possibly boosted locally) whose world volume spans a curved submanifold of the spacetime. This approach reveals black objects with novel horizon geometries and topologies more complex than the black ring, but more generally it provides a new organizing framework for the dynamics of higher-dimensional black holes.
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. PMID:12817138
International Nuclear Information System (INIS)
The quantum statistics of charged, extremal black holes is investigated beginning with the hypothesis that the quantum state is a functional on the space of closed three-geometries, with each black hole connected to an oppositely charged black hole through a spatial wormhole. From this starting point a simple argument is given that a collection of extremal black holes obeys neither Bose nor Fermi statistics. Rather, they obey an exotic variety of particle statistics known as ''infinite statistics'' which resembles that of distinguishable particles and is realized by a q deformation of the quantum commutation relations
Neves, J C S
2015-01-01
In this work, we have deformed regular black holes which possess a general mass term described by a function which generalizes the Bardeen and Hayward mass terms. Using linear constraints in the energy-momentum tensor, the solutions are either regular or singular. That is, with this approach, it is possible to generate singular black holes from regular black holes and vice versa. Moreover, contrary to the Bardeen and Hayward regular solutions, the regular deformed metrics may violate the weak energy condition despite the presence of the spherical symmetry. Some comments on accretion of deformed black holes in cosmological scenarios are made.
White holes and eternal black holes
International Nuclear Information System (INIS)
We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi-thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal. (paper)
White holes and eternal black holes
Stephen D. H. Hsu
2010-01-01
We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi- thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal.
MicroBlack Holes Thermodynamics in the Presence of Quantum Gravity Effects
Directory of Open Access Journals (Sweden)
H. Soltani
2014-01-01
Full Text Available Black hole thermodynamics is corrected in the presence of quantum gravity effects. Some phenomenological aspects of quantum gravity proposal can be addressed through generalized uncertainty principle (GUP which provides a perturbation framework to perform required modifications of the black hole quantities. In this paper, we consider the effects of both a minimal measurable length and a maximal momentum on the thermodynamics of TeV-scale black holes. We then extend our study to the case that there are all natural cutoffs as minimal length, minimal momentum, and maximal momentum simultaneously. We also generalize our study to the model universes with large extra dimensions (LED. In this framework existence of black holes remnants as a possible candidate for dark matter is discussed. We study probability of black hole production in the Large Hadronic Collider (LHC and we show this rate decreasing for sufficiently large values of the GUP parameter.
MicroBlack Holes Thermodynamics in the Presence of Quantum Gravity Effects
International Nuclear Information System (INIS)
Black hole thermodynamics is corrected in the presence of quantum gravity effects. Some phenomenological aspects of quantum gravity proposal can be addressed through generalized uncertainty principle (GUP) which provides a perturbation framework to perform required modifications of the black hole quantities. In this paper, we consider the effects of both a minimal measurable length and a maximal momentum on the thermodynamics of TeV-scale black holes. We then extend our study to the case that there are all natural cutoffs as minimal length, minimal momentum, and maximal momentum simultaneously. We also generalize our study to the model universes with large extra dimensions (LED). In this framework existence of black holes remnants as a possible candidate for dark matter is discussed. We study probability of black hole production in the Large Hadronic Collider (LHC) and we show this rate decreasing for sufficiently large values of the GUP parameter
Effects of critical collapse on primordial black-hole mass spectra
Energy Technology Data Exchange (ETDEWEB)
Kuehnel, Florian [Stockholm University, AlbaNova, Department of Physics, The Oskar Klein Centre for Cosmoparticle Physics, Stockholm (Sweden); Rampf, Cornelius [University of Portsmouth, Institute of Cosmology and Gravitation, Portsmouth (United Kingdom); Sandstad, Marit [Stockholm University, Nordita, KTH Royal Institute of Technology, Stockholm (Sweden)
2016-02-15
Certain inflationary models as well as realisations of phase transitions in the early Universe predict the formation of primordial black holes. For most mass ranges, the fraction of matter in the form of primordial black holes is limited by many different observations on various scales. Primordial black holes are assumed to be formed when overdensities that cross the horizon have Schwarzschild radii larger than the horizon. Traditionally it was therefore assumed that primordial black-hole masses were equal to the horizon mass at their time of formation. However, detailed calculations of their collapse show that primordial black holes formed at each point in time should rather form a spectrum of different masses, obeying critical scaling. Though this has been known for more than 15 years, the effect of this scaling behaviour is largely ignored when considering predictions for primordial black-hole mass spectra. In this paper we consider the critical collapse scaling for a variety of models which produce primordial black holes, and find that it generally leads to a shift, broadening and an overall decrease of the mass contained in primordial black holes. This effect is model and parameter dependent and cannot be contained by a constant rescaling of the spectrum; it can become important and should be taken into account when comparing to observational constraints. (orig.)
Effects of critical collapse on primordial black-hole mass spectra
International Nuclear Information System (INIS)
Certain inflationary models as well as realisations of phase transitions in the early Universe predict the formation of primordial black holes. For most mass ranges, the fraction of matter in the form of primordial black holes is limited by many different observations on various scales. Primordial black holes are assumed to be formed when overdensities that cross the horizon have Schwarzschild radii larger than the horizon. Traditionally it was therefore assumed that primordial black-hole masses were equal to the horizon mass at their time of formation. However, detailed calculations of their collapse show that primordial black holes formed at each point in time should rather form a spectrum of different masses, obeying critical scaling. Though this has been known for more than 15 years, the effect of this scaling behaviour is largely ignored when considering predictions for primordial black-hole mass spectra. In this paper we consider the critical collapse scaling for a variety of models which produce primordial black holes, and find that it generally leads to a shift, broadening and an overall decrease of the mass contained in primordial black holes. This effect is model and parameter dependent and cannot be contained by a constant rescaling of the spectrum; it can become important and should be taken into account when comparing to observational constraints. (orig.)
Taniguchi, Keisuke; Baumgarte, Thomas W.; Faber, Joshua A.; Shapiro, Stuart L.
2007-01-01
We construct new models of black hole-neutron star binaries in quasiequilibrium circular orbits by solving Einstein's constraint equations in the conformal thin-sandwich decomposition together with the relativistic equations of hydrostationary equilibrium. We adopt maximal slicing, assume spatial conformal flatness, and impose equilibrium boundary conditions on an excision surface (i.e., the apparent horizon) to model the black hole. In our previous treatment we adopted a "leading-order" appr...
Black holes and the multiverse
Garriga, Jaume; Zhang, Jun
2015-01-01
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 blac...
Noncommutative Solitonic Black Hole
Chang-Young, Ee; Kimm, Kyoungtae; Lee, Daeho; Lee, Youngone
2011-01-01
We investigate solitonic black hole solutions in three dimensional noncommutative spacetime. We do this in gravity with negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find t...
Noncommutative Singular Black Holes
International Nuclear Information System (INIS)
In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t - r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.
Noncommutative Singular Black Holes
Hamid Mehdipour, S.
2010-11-01
In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t — r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.
DEFF Research Database (Denmark)
Kragh, Helge Stjernholm
2016-01-01
Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....
Bousso, R.; Hawking, S. W.
1997-08-01
We summarise recent work on the quantum production of black holes in the inflationary era. We describe, in simple terms, the Euclidean approach used, and the results obtained both for the pair creation rate and for the evolution of the black holes.
Indian Academy of Sciences (India)
Koustubh Ajit Kabe
2012-09-01
In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of thermodynamics. Nine fundamental black hole dynamical relations have been developed akin to the four fundamental thermodynamic relations of Maxwell. The specific heats , and , have been defined. For a black hole, these quantities are negative. The d equation has been obtained as an application of these fundamental relations. Time reversible processes observing constancy of surface gravity are considered and an equation connecting the internal energy of the black hole , the additional available energy defined as the first free energy function , and the surface gravity , has been obtained. Finally as a further application of the fundamental relations, it has been proved for a homogeneous gravitational field in black hole space times or a de Sitter black hole that $C_{\\Omega,\\Phi}-C_{J,Q}=\\kappa \\left[\\left(\\dfrac{\\partial J}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial \\Omega}{\\partial \\kappa}\\right)_{J,Q}+\\left(\\dfrac{\\partial Q}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial\\Phi}{\\partial \\kappa}\\right)_{J,Q}\\right]$. This is dubbed as the homogeneous fluid approximation in context of the black holes.
An effective search method for gravitational ringing of black holes
International Nuclear Information System (INIS)
We develop a search method for gravitational ringing of black holes. The gravitational ringing is due to complex frequency modes called the quasinormal modes that are excited when a black hole geometry is perturbed. The detection of it will be a direct confirmation of the existence of a black hole. Assuming that the ringdown waves are dominated by the least-damped (fundamental) mode with the least imaginary part, we consider matched filtering and develop an optimal method to search for the ringdown waves that have damped sinusoidal wave forms. When we use the matched filtering method, a data analysis with a lot of templates is required. Here we have to ensure a proper match between the filter as a template and the real wave. It is necessary to keep the detection efficiency as high as possible under limited computational costs. First, we consider the white noise case for which the matched filtering can be studied analytically. We construct an efficient method for tiling the template space. Then, using a fitting curve of the TAMA300 DT7 noise spectrum, we numerically consider the case of colored noise. We find our tiling method developed for the white noise case is still valid even if the noise is colored
An Effective Search Method for Gravitational Ringing of Black Holes
Nakano, H; Tagoshi, H; Sasaki, M; Nakano, Hiroyuki; Sasaki, Misao; Tagoshi, Hideyuki; Takahashi, Hirotaka
2003-01-01
We develop a search method for gravitational ringing of black holes. The gravitational ringing is due to complex frequency modes called the quasi-normal modes that are excited when a black hole geometry is perturbed. The detection of it will be a direct confirmation of the existence of a black hole. Assuming that the ringdown waves are dominated by the fundamental mode with least imaginary part, we consider matched filtering and develop an optimal method to search for the ringdown waves that have damped sinusoidal wave forms. When we use the matched filtering method, the data analysis with a lot of templates required. Here we have to ensure a proper match between the filter as a template and the real wave. It is necessary to keep the detection efficiency as high as possible under limited computational costs. First, we consider the white noise case for which the matched filtering can be studied analytically. We construct an efficient method for tiling the template space. Then, using a fitting curve of the TAMA...
Numerical Study of the Superresonance Effect and Energy Flow in Acoustic Black Holes
Choy, K; Carrington, M E; Fugleberg, T; Zahn, J; Kobes, R; Kunstatter, G; Pickering, D
2005-01-01
We present the results of a numerical study of the superresonance effect of scalar fields incident on an acoustic black hole. We show that the superresonance effect is quite large compared with the analogous effect in a Kerr black hole. We present an explicit analysis of the energy flow from these numerical solutions to determine where the outward flow of energy originates and confirm that the superresonance effect is a real physical effect.
Kuchiev, M Yu
2003-01-01
Black holes are presumed to have an ideal ability to absorb and keep matter. Whatever comes close to the event horizon, a boundary separating the inside region of a black hole from the outside world, inevitably goes in and remains inside forever. This work shows, however, that quantum corrections make possible a surprising process, reflection: a particle can bounce back from the event horizon. For low energy particles this process is efficient, black holes behave not as holes, but as mirrors, which changes our perception of their physical nature. Possible ways for observations of the reflection and its relation to the Hawking radiation process are outlined.
Evolution of massive black holes
Volonteri, Marta
2007-01-01
Supermassive black holes are nowadays believed to reside in most local galaxies. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I'll discuss black hole formation processes that are likely to place at early cosmic epochs, and how massive black hole evolve in a hierarchical Universe...
Hajdukovic, D
2006-01-01
We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.
Lyutikov, Maxim
2011-01-01
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 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 $N_B = e \\Phi_\\infty /(\\pi c \\hbar)$, where $\\Phi_\\infty \\approx 2 \\pi^2 B_{NS} R_{NS}^3 /(P_{\\rm NS} c)$ is the initial magnetic flux through the hemisphere...
Thermal corpuscular black holes
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.
Numerical resolution effects on simulations of massive black hole seeds
Regan, John A; Haehnelt, Martin G
2013-01-01
We have performed high-resolution numerical simulations with the hydrodynamical AMR code Enzo to investigate the formation of massive seed black holes in a sample of six dark matter haloes above the atomic cooling threshold. The aim of this study is to illustrate the effects of varying the maximum refinement level on the final object formed. The virial temperatures of the simulated haloes range from $\\rm{T} \\sim 10000\\ \\rm{K} - 16000\\ \\rm{K}$ and they have virial masses in the range $\\rm{M} \\sim 2 \\times 10^7 \\rm{M_{\\odot}}$ to $\\rm{M} \\sim 7 \\times 10^7 \\rm{M_{\\odot}}$ at $z \\sim 15$. The outcome of our six fiducial simulations is both generic and robust. A rotationally supported, marginally gravitationally stable, disk forms with an exponential profile. The mass and scale length of this disk depends strongly on the maximum refinement level used. Varying the maximum refinement level by factors between 1 / 64 to 256 times the fiducial level illustrates the care that must be taken in interpreting the results. ...
Ahn, Eun-Joo; Cavaglia, Marco
2003-01-01
Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes can be used to probe physical properties of the very early universe which would usually require the knowledge of the theory of quantum gravity. They may be the only tool to explore thermalisation of the early universe. Whereas the creation of cosmic black ...
Effects of Thermal Fluctuations on the Thermodynamics of Modified Hayward Black Hole
Pourhassan, Behnam; Debnath, Ujjal
2016-01-01
In this work, we analyze the effects of thermal fluctuations on the thermodynamics of a modified Hayward black hole. These thermal fluctuations will produce correction terms for various thermodynamic quantities like entropy, pressure, inner energy and specific heats. We also investigate the effect of these correction terms on the first law of thermodynamics. Finally, we study the phase transition for the modified Hayward black hole. It is demonstrated that the modified Hayward black hole is stable even after the thermal fluctuations are taken into account, as long as the event horizon is larger than a certain critical value.
Effects of thermal fluctuations on the thermodynamics of modified Hayward black hole
Energy Technology Data Exchange (ETDEWEB)
Pourhassan, Behnam [Damghan University, School of Physics, Damghan (Iran, Islamic Republic of); Faizal, Mir [University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Debnath, Ujjal [Indian Institute of Engineering Science and Technology, Shibpur, Department of Mathematics, Howrah (India)
2016-03-15
In this work, we analyze the effects of thermal fluctuations on the thermodynamics of a modified Hayward black hole. These thermal fluctuations will produce correction terms for various thermodynamical quantities like entropy, pressure, internal energy, and specific heats. We also investigate the effect of these correction terms on the first law of thermodynamics. Finally, we study the phase transition for the modified Hayward black hole. It is demonstrated that the modified Hayward black hole is stable even after the thermal fluctuations are taken into account, as long as the event horizon is larger than a certain critical value. (orig.)
Effects of thermal fluctuations on the thermodynamics of modified Hayward black hole
International Nuclear Information System (INIS)
In this work, we analyze the effects of thermal fluctuations on the thermodynamics of a modified Hayward black hole. These thermal fluctuations will produce correction terms for various thermodynamical quantities like entropy, pressure, internal energy, and specific heats. We also investigate the effect of these correction terms on the first law of thermodynamics. Finally, we study the phase transition for the modified Hayward black hole. It is demonstrated that the modified Hayward black hole is stable even after the thermal fluctuations are taken into account, as long as the event horizon is larger than a certain critical value. (orig.)
Switching off black hole evaporation
International Nuclear Information System (INIS)
The inclusion of the back-reaction in the Hawking effect leads to the result that, if vector boson fields predominate in nature, then black holes stop evaporating when their mass reaches a non-vanishing limiting value. (author)
Black holes and Higgs stability
Tetradis, Nikolaos
2016-01-01
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.
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. PMID:25768747
Non-existence of New Quantum Ergosphere Effect of a Vaidya-type Black Hole
Wu, S Q
2001-01-01
Hawking evaporation of Dirac particles and scalar fields in a Vaidya-type black hole is investigated by the method of generalized tortoise coordinate transformation. It is shown that Hawking radiation of Dirac particles does not exist for $P_1, Q_2$ components but for $P_2, Q_1$ components in any Vaidya-type black holes. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles. We demonstrates that there is no new quantum ergosphere effect in the thermal radiation of Dirac particles in any spherically symmetry black holes.
Effects of dark energy on P-V criticality of charged AdS black holes
Li, Gu-Qiang
2014-01-01
In this Letter, we investigate the effects of dark energy on $P-V$ criticality of charged AdS black holes by considering the case of the RN-AdS black holes surrounded by quintessence. By treating the cosmological constant as thermodynamic pressure, we study its thermodynamics in the extended phase space. It is shown that quintessence dark energy does not affect the existence of small/large black hole phase transition. For the case $\\omega_q=-2/3$ we derive analytic expressions of critical phy...
EFFECT OF A DARK MATTER HALO ON THE DETERMINATION OF BLACK HOLE MASSES
International Nuclear Information System (INIS)
Stellar dynamical modeling is a powerful method to determine the mass of black holes in quiescent galaxies. However, in previous work the presence of a dark matter halo has been ignored in the modeling. Gebhardt and Thomas in 2009 showed that accounting for a dark matter halo increased the black hole mass of the massive galaxy M87 by a factor of two. We used a sample of 12 galaxies to investigate the effect of accounting for a dark matter halo in the dynamical modeling in more detail, and also updated the masses using improved modeling. The sample of galaxies possesses Hubble Space Telescope and ground-based observations of stellar kinematics. Their black hole masses have been presented before, but without including a dark matter halo in the models. Without a dark halo, we find a mean increase in the estimated mass of 1.5 for the whole sample compared to previous results. We attribute this change to using a more complete orbit library. When we include a dark matter halo, along with the updated models, we find an additional increase in black hole mass by a factor of 1.2 in the mean, much less than for M87. We attribute the smaller discrepancy in black hole mass to using data that better resolve the black hole's sphere of influence. We redetermined the M.-σ* and M.-LV relationships using our updated black hole masses and found a slight increase in both normalization and intrinsic scatter.
Noncommutative Solitonic Black Hole
Chang-Young, Ee; Lee, Daeho; Lee, Youngone
2012-01-01
We investigate solitonic black hole solutions in three dimensional noncommutative spacetime. We do this in gravity with negative cosmological constant coupled to a scalar field using the Moyal product expanded up to first order in the noncommutativity parameter in the two noncommutative spatial directions. By numerical simulation we look for black hole solutions by increasing the non- commutativity parameter value starting from regular solutions with vanishing noncommutativity. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value.
Hayward, Sean Alan
2013-01-01
Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h
International Nuclear Information System (INIS)
In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn
Energy Technology Data Exchange (ETDEWEB)
Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)
2015-05-11
In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.
Kleihaus, Burkhard; Yazadjiev, Stoytcho
2015-01-01
In the presence of a complex scalar field scalar-tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and ordinary hairy black holes. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.
Radiatively Driven Winds from Effective Boundary Layer around Black Holes
Indian Academy of Sciences (India)
Indranil Chattopadhyay; Sandip K. Chakrabarti
2002-03-01
Matter accreting onto black holes suffers a standing or oscillating shock wave in much of the parameter space. The post-shock region is hot, puffed up and reprocesses soft photons from a Keplerian disc to produce the characteristic hard tail of the spectrum of accretion discs. The post-shock torus is also the base of the bipolar jets. We study the interaction of these jets with the hard photons emitted from the disc. We show that radiative force can accelerate outflows but the drag can limit the terminal speed. We introduce an equilibrium speed eq as a function of distance, above which the flow will experience radiative deceleration.
Testing quantum gravity effects through Dyonic charged AdS black hole
Sadeghi, J; Rostami, M
2016-01-01
In this paper, we consider dyonic charged AdS black hole which is holographic dual of a van der Waals fluid. We use logarithmic corrected entropy and study thermodynamics of the black hole and show that holographic picture is still valid. Critical behaviors and stability also discussed. Logarithmic corrections arises due to thermal fluctuations which are important when size of black hole be small. So, thermal fluctuations interpreted as quantum effect. It means that we can see quantum effect of a black hole which is a gravitational system. Hence, one can use result of this paper to compare with that of van der Waals fluid in the lab and see quantum gravity effects.
Energy conservation for dynamical black holes
Hayward, Sean A.
2004-01-01
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. For a growing black hole, this first law of black-hole dynamics is equivalent to an equation of Ashtekar & Krishnan, but the new integral and differential forms are regular in the limit where the black hole ceases to grow. An effective gravitational-radiation energy tensor is obtained, providing measures o...
Stationary Scalar Clouds Around Rotating Black Holes
Hod, Shahar
2012-01-01
Motivated by novel results in the theory of wave dynamics in black-hole spacetimes, we analyze the dynamics of a massive scalar field surrounding a rapidly rotating Kerr black hole. In particular, we report on the existence of stationary (infinitely long-lived) regular field configurations in the background of maximally rotating black holes. The effective height of these scalar "clouds" above the central black hole is determined analytically. Our results support the possible existence of stat...
Black hole thermodynamics from decoherence
Guo, Xiao-Kan
2015-01-01
We present an approach to the four laws of black hole thermodynamics by utilizing the thermodynamics of quantum coherence. Firstly, Hawking effect is attributed to the decoherence of the two-mode squeezed state in a black hole spacetime. Then use is made of the relative entropy between undecohered and decohered squeezed states whose monotonicity gives the zeroth and the second law, while the first law can be obtained either by the vanishing of the first derivative of relative entropy or by studying the effective thermal model generated by the modular Hamiltonian. Futhermore, information-theoretic arguments give a Planck's form of the third law of black hole thermodynamics. With this approach we can understand the laboratory analogues of black holes solely by quantum theory. This approach also opens a way to reconstruct classical geometry from quantum gravity.
Signatures of black holes at the LHC
Cavaglia, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.
2007-01-01
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.
Light geodesics near an evaporating black hole
Guerreiro, Thiago; Monteiro, Fernando
2015-10-01
Quantum effects imply that an infalling observer cannot cross the event horizon of an evaporating black hole, even in her proper time. The Penrose diagram of an evaporating black hole is different from the one usually reported in the literature. We show that before the observer can cross the horizon the black hole disappears. Possible observational consequences are discussed.
On Quantum Contributions to Black Hole Growth
Spaans, M.
2013-01-01
The effects of Wheeler’s quantum foam on black hole growth are explored from an astrophysical per- spective. Quantum fluctuations in the form of mini (10−5 g) black holes can couple to macroscopic black holes and allow the latter to grow exponentially in mass on a time scale of 109 years. Consequent
On Noncommutative Black Holes Thermodynamics
Faizal, Mir; Ulhoa, S C
2015-01-01
In this paper, we will analyze noncommutative deformation of the Schwarzschild black holes and Kerr black holes. We will perform our analysis by relating the commutative and the noncommutative metrics using an Moyal product. We will also analyze the thermodynamics of these noncommutative black hole solutions. We will explicitly derive expression for the corrected entropy and temperature of these black hole solutions.
The Thermodynamics of Black Holes
Directory of Open Access Journals (Sweden)
Wald Robert M.
2001-01-01
Full Text Available We review the present status of black hole thermodynamics. Our review includes discussion of classical black hole thermodynamics, Hawking radiation from black holes, the generalized second law, and the issue of entropy bounds. A brief survey also is given of approaches to the calculation of black hole entropy. We conclude with a discussion of some unresolved open issues.
The Thermodynamics of Black Holes
Wald Robert M.
1999-01-01
We review the present status of black hole thermodynamics. Our review includes discussion of classical black hole thermodynamics, Hawking radiation from black holes, the generalized second law, and the issue of entropy bounds. A brief survey also is given of approaches to the calculation of black hole entropy. We conclude with a discussion of some unresolved open issues.
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)
International Nuclear Information System (INIS)
In this review we shall concentrate on the application of the concept of black hole to different areas in astrophysics. Models in which this idea is involved are connected with basically two areas in astrophysics: a) The death of massive stars due to gravitational collapse. This process would lead to the formation of black holes with stellar masses (10-20 M sun). The detection of these kind of - objects is in principle possible, by means of studying the so-called X-ray binary system. b) Active nuclei of galaxies, including quasars as an extreme case. In this case, the best model available to explain the generation of the enormous amounts of energy observed as well as several other properties, is accretion into a supermassive black hole (106-1010 M sun) in the center. The problem of the origin of such black holes is related to cosmology. (author)
Detection of pulsar beams deflected by the black hole in SGR A*: Effects of black hole spin
International Nuclear Information System (INIS)
Some Galactic models predict a significant population of radio pulsars close to the Galactic center. Beams from these pulsars could be strongly deflected by the supermassive black hole (SMBH) believed to reside at the Galactic center and as a result reach Earth. Earlier work assuming a Schwarzschild SMBH gave marginal chances of observing this exotic phenomenon with current telescopes and good chances with future telescopes. Here we study whether those estimates are significantly affected by SMBH spin. We find that spin effects make a negligible difference in detectability, but the pattern of pulse arrival times is clearly affected. In particular, if strongly deflected beams are detected, the SMBH spin signature could be extracted from pulsar beam times of arrival.
Constraints on Black Hole Remnants
Giddings, S. B.
1993-01-01
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 c...
Black hole thermodynamics from decoherence
Guo, Xiao-Kan
2015-01-01
We present an approach to the four laws of black hole thermodynamics by utilizing the thermodynamics of quantum coherence. Firstly, Hawking effect is attributed to the decoherence of the two-mode squeezed state in a black hole spacetime. Then use is made of the relative entropy between undecohered and decohered squeezed states whose monotonicity gives the zeroth and the second law, while the first law can be obtained either by the vanishing of the first derivative of relative entropy or by st...
Inclination and relativistic effects in the outburst evolution of black hole transients
Munoz-Darias, T.; Coriat, M.; Plant, D. S.; Ponti, G.; Fender, R. P.; Dunn, R. J. H.
2013-01-01
We have systematically studied the effect of the orbital inclination in the outburst evolution of black hole transients. We have included all the systems observed by the Rossi X-ray Timing Explorer in which the thermal, accretion disc component becomes strongly dominant at some point of the outburst. Inclination is found to modify the shape of the tracks that these systems display in the colour/luminosity diagrams traditionally used for their study. Black hole transients seen at low inclinati...
Perturbed disks get shocked. Binary black hole merger effects on accretion disks
Megevand, Miguel; Anderson, Matthew; Frank, Juhan; Hirschmann, Eric W.; Lehner, Luis; Liebling, Steven L.; Motl, Patrick M; Neilsen, David
2009-01-01
The merger process of a binary black hole system can have a strong impact on a circumbinary disk. In the present work we study the effect of both central mass reduction (due to the energy loss through gravitational waves) and a possible black hole recoil (due to asymmetric emission of gravitational radiation). For the mass reduction case and recoil directed along the disk's angular momentum, oscillations are induced in the disk which then modulate the internal energy and bremsstrahlung lumino...
Charged Fermions Tunnel from the Kerr-Newman Black Hole Influenced by Quantum Gravity Effects
Ren, Ruyi; Chen, Deyou; Pu, Jin
2016-03-01
Taking into account quantum gravity effects, we investigate the tunnelling radiation of charged fermions in the Kerr-Newman black hole. The result shows that the corrected Hawking temperature is determined not only by the parameters of the black hole, but also by the energy, angular momentum and mass of the emitted fermion. Meanwhile, an interesting found is that the temperature is affected by the angle 𝜃. The quantum gravity correction slows down the evaporation.
Stornaiolo, Cosimo
2001-01-01
In this paper we propose a model for the formation of the cosmological voids. We show that cosmological voids can form directly after the collapse of extremely large wavelength perturbations into low-density black holes or cosmological black holes (CBH). Consequently the voids are formed by the comoving expansion of the matter that surrounds the collapsed perturbation. It follows that the universe evolves, in first approximation, according to the Einstein-Straus cosmological model. We discuss...
International Nuclear Information System (INIS)
No particle theory can be complete without gravity. Einstein's theory of gravity is of the Euler-Lagrange form, but standard quantization procedure fails. In quantum gravity the higher order interactions have a dimensionality different form the fundamental ones, because Newton's constant G has dimensions and the renormalization procedure fails. Another problem with quantum gravity is even more mysterious. Suppose that we had regularized the gravitational forces at the small distance end in the way that the weak intermediate vector boson regularized the fundamental 4-fermion interaction vertex of the weak interactions. Then what we discover is that the gravitational forces are unstable. Given sufficiently large amount of matter, it can collapse under its own weight. Classical general relativity tells us what will happen: a black hole is formed. But how is this formulated in quantum theory. S. Hawking observed that when a field theory is quantized in the background metric of a black hole, the black hole actually emits particles in a completely random thermal way. Apparently black holes are just another form of matter unstable against Hawking decay. Unfortunately this picture cannot be complete. The problem is that the quantum version of black holes has infinite phase space, and other symptoms of a run-away solution. Black holes are the heaviest and most compact forms of matter that can be imagined. A complete particle theory can have nothing but a spectrum of black-hole like objects at it high-energy end. This is why it is believed that a resolution of the black hole problem will in time disclose the complete small-distance structure of our world. 6 references
Thermal corpuscular black holes
Casadio, Roberto; Giugno, Andrea; Orlandi, Alessio
2015-01-01
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 $\\omega>m$). Each constituent is in a superposition of the ground state and a Planckian distribution at the expected Hawking temp...
Black hole critical phenomena without black holes
Indian Academy of Sciences (India)
Steven L Liebling
2000-10-01
Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I brieﬂy review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.
Black hole evaporation: a paradigm
International Nuclear Information System (INIS)
A paradigm describing black hole evaporation in non-perturbative quantum gravity is developed by combining two sets of detailed results: (i) resolution of the Schwarzschild singularity using quantum geometry methods and (ii) time evolution of black holes in the trapping and dynamical horizon frameworks. Quantum geometry effects introduce a major modification in the traditional spacetime diagram of black hole evaporation, providing a possible mechanism for recovery of information that is classically lost in the process of black hole formation. The paradigm is developed directly in the Lorentzian regime and necessary conditions for its viability are discussed. If these conditions are met, much of the tension between expectations based on spacetime geometry and structure of quantum theory would be resolved
Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar
2015-05-01
We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.
Accurate Waveforms for Non-spinning Binary Black Holes using the Effective-one-body Approach
Buonanno, Alessandra; Pan, Yi; Baker, John G.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; vanMeter, James R.
2007-01-01
Using numerical relativity as guidance and the natural flexibility of the effective-one-body (EOB) model, we extend the latter so that it can successfully match the numerical relativity waveforms of non-spinning binary black holes during the last stages of inspiral, merger and ringdown. Here, by successfully, we mean with phase differences black-hole masses. The final black-hole mass and spin predicted by the numerical simulations are used to determine the ringdown frequency and decay time of three quasi-normal-mode damped sinusoids that are attached to the EOB inspiral-(plunge) waveform at the light-ring. The accurate EOB waveforms may be employed for coherent searches of gravitational waves emitted by non-spinning coalescing binary black holes with ground-based laser-interferometer detectors.
Supermassive binary black holes - possible observational effects in the x-ray emission
Directory of Open Access Journals (Sweden)
Jovanović Predrag
2014-01-01
Full Text Available Here we discuss the possible observational effects in the X-ray emission from two relativistic accretion disks in a supermassive binary black hole system. For that purpose we developed a model and performed numerical simulations of the X-ray radiation from a relativistic accretion disk around a supermassive black hole, based on the ray-tracing method in the Kerr metric, and applied it to the case of the close binary supermassive black holes. Our results indicate that the broad Fe Kα line is a powerful tool for detecting such systems and studying their properties. The most favorable candidates for observational studies are the supermassive binary black holes in the galactic mergers during the phase when the orbital velocities of their components are very large and exceed several thousand kms -1. [Projekat Ministarstva nauke Republike Srbije, br. 176003: Gravitation and the Large Scale Structure of the Universe i br. 176001: Astrophysical Spectroscopy of Extragalactic Objects
Effects of dark energy on P–V criticality of charged AdS black holes
International Nuclear Information System (INIS)
In this Letter, we investigate the effects of dark energy on P–V criticality of charged AdS black holes by considering the case of the RN-AdS black holes surrounded by quintessence. By treating the cosmological constant as thermodynamic pressure, we study its thermodynamics in the extended phase space. It is shown that quintessence dark energy does not affect the existence of small/large black hole phase transition. For the case ωq=−2/3 we derive analytic expressions of critical physical quantities, while for cases ωq≠−2/3 we appeal to numerical method for help. It is shown that quintessence dark energy affects the critical physical quantities near the critical point. Critical exponents are also calculated. They are exactly the same as those obtained before for arbitrary other AdS black holes, which implies that quintessence dark energy does not change the critical exponents
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…
Cosmic censorship inside black holes
Thorlacius, L
2006-01-01
A simple argument is given that a traversable Cauchy horizon inside a black hole is incompatible with unitary black hole evolution. The argument assumes the validity of black hole complementarity and applies to a generic black hole carrying angular momentum and/or charge. In the second part of the paper we review recent work on the semiclassical geometry of two-dimensional charged black holes.
Bekenstein, Jacob D.
1997-01-01
In some respects the black hole plays the same role in gravitation that the atom played in the nascent quantum mechanics. This analogy suggests that black hole mass $M$ might have a discrete spectrum. I review the physical arguments for the expectation that black hole horizon area eigenvalues are uniformly spaced, or equivalently, that the spacing between stationary black hole mass levels behaves like 1/M. This sort of spectrum has also emerged in a variety of formal approaches to black hole ...
STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS
International Nuclear Information System (INIS)
If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.
Strong Field Effects on Emission Line Profiles: Kerr Black Holes and Warped Accretion Disks
Wang, Yan; Li, Xiang-Dong
2012-01-01
If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.
Black holes under external inﬂuence
Indian Academy of Sciences (India)
Jiří Bičák
2000-10-01
The work on black holes immersed in external ﬁelds is reviewed in both test-ﬁeld approximation and within exact solutions. In particular we pay attention to the effect of the expulsion of the ﬂux of external ﬁelds across charged and rotating black holes which are approaching extremal states. Recently this effect has been shown to occur for black hole solutions in string theory. We also discuss black holes surrounded by rings and disks and rotating black holes accelerated by strings.
Directory of Open Access Journals (Sweden)
Roberto Casadio
2015-10-01
Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the 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 = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce
Belloni, T M
2016-01-01
The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...
Black holes: the membrane paradigm
International Nuclear Information System (INIS)
The physics of black holes is explored in terms of a membrane paradigm which treats the event horizon as a two-dimensional membrane embedded in three-dimensional space. A 3+1 formalism is used to split Schwarzschild space-time and the laws of physics outside a nonrotating hole, which permits treatment of the atmosphere in terms of the physical properties of thin slices. The model is applied to perturbed slowly or rapidly rotating and nonrotating holes, and to quantify the electric and magnetic fields and eddy currents passing through a membrane surface which represents a stretched horizon. Features of tidal gravitational fields in the vicinity of the horizon, quasars and active galalctic nuclei, the alignment of jets perpendicular to accretion disks, and the effects of black holes at the center of ellipsoidal star clusters are investigated. Attention is also given to a black hole in a binary system and the interactions of black holes with matter that is either near or very far from the event horizon. Finally, a statistical mechanics treatment is used to derive a second law of thermodynamics for a perfectly thermal atmosphere of a black hole
Charged rotating black holes at large D
Tanabe, Kentaro
2016-01-01
We study odd dimensional charged equally rotating black holes in the Einstein-Maxwell theory with/without a cosmological constant by using the large D expansion method, where D is a spacetime dimension. Solving the Einstein-Maxwell equations in the 1/D expansion we obtain the large D effective equations for charged equally rotating black holes. The effective equations describe the nonlinear dynamics of charged equally rotating black holes. Especially the perturbation analysis of the effective equations gives analytic formula for quasinormal mode frequencies, and we can show charged equally rotating black holes have instabilities. As one interesting feature of instabilities, we observe that the ultraspinning instability of neutral equally rotating black holes in de Sitter is connected with the instability of de Sitter Reissner-Nordstrom black hole in a rotation-charge plane of the solution parameter space. So these instabilities have same origin as dynamical properties of charged rotating black holes. We also ...
Stationary Scalar Clouds Around Rotating Black Holes
Hod, Shahar
2012-01-01
Motivated by novel results in the theory of wave dynamics in black-hole spacetimes, we analyze the dynamics of a massive scalar field surrounding a rapidly rotating Kerr black hole. In particular, we report on the existence of stationary (infinitely long-lived) regular field configurations in the background of maximally rotating black holes. The effective height of these scalar "clouds" above the central black hole is determined analytically. Our results support the possible existence of stationary scalar field dark matter distributions surrounding rapidly rotating black holes.
Thermal corpuscular black holes
Casadio, Roberto; Orlandi, Alessio
2015-01-01
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 $\\omega>m$). 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 preci...
Quantum black hole evaporation
Schoutens, K; Verlinde, Erik; Schoutens, Kareljan; Verlinde, Erik; Verlinde, Herman
1993-01-01
We investigate a recently proposed model for a full quantum description of two-dimensional black hole evaporation, in which a reflecting boundary condition is imposed in the strong coupling region. It is shown that in this model each initial state is mapped to a well-defined asymptotic out-state, provided one performs a certain projection in the gravitational zero mode sector. We find that for an incoming localized energy pulse, the corresponding out-going state contains approximately thermal radiation, in accordance with semi-classical predictions. In addition, our model allows for certain acausal strong coupling effects near the singularity, that give rise to corrections to the Hawking spectrum and restore the coherence of the out-state. To an asymptotic observer these corrections appear to originate from behind the receding apparent horizon and start to influence the out-going state long before the black hole has emitted most of its mass. Finally, by putting the system in a finite box, we are able to deriv...
Hawking, S. W.
1996-03-01
One would expect spacetime to have a foamlike structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the nontrivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of S2×S2 and K3 bubbles. Comparison with the instantons for pair creation of black holes shows that the S2×S2 bubbles can be interpreted as closed loops of virtual black holes. It is shown that scattering in such topological fluctuations leads to loss of quantum coherence, or in other words, to a superscattering matrix S/ that does not factorize into an S matrix and its adjoint. This loss of quantum coherence is very small at low energies for everything except scalar fields, leading to the prediction that we may never observe the Higgs particle. Another possible observational consequence may be that the θ angle of QCD is zero without having to invoke the problematical existence of a light axion. The picture of virtual black holes given here also suggests that macroscopic black holes will evaporate down to the Planck size and then disappear in the sea of virtual black holes.
Babichev, Eugeny; Hassaine, Mokhtar
2015-01-01
We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...
Quantum information erasure inside black holes
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.
Quantum information erasure inside black holes
Lowe, David A
2015-01-01
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.
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. PMID:25768746
International Nuclear Information System (INIS)
General consensus on the nature of the degrees of freedom responsible for the black hole entropy remains elusive despite decades of effort dedicated to the problem. Different approaches to quantum gravity disagree in their description of the microstates and, more significantly, in the statistics used to count them. In some approaches (string theory, AdS/CFT) the elementary degrees of freedom are indistinguishable, whereas they must be treated as distinguishable in other approaches to quantum gravity (eg., LQG) in order to recover the Bekenstein-Hawking area-entropy law. However, different statistics will imply different behaviors of the black hole outside the thermodynamic limit. We illustrate this point by quantizing the Bañados-Teitelboim-Zanelli (BTZ) black hole, for which we argue that Bose condensation will occur leading to a cold, stable remnant
Vaz, Cenalo; Wijewardhana, L. C. R.
2013-12-01
General consensus on the nature of the degrees of freedom responsible for the black hole entropy remains elusive despite decades of effort dedicated to the problem. Different approaches to quantum gravity disagree in their description of the microstates and, more significantly, in the statistics used to count them. In some approaches (string theory, AdS/CFT) the elementary degrees of freedom are indistinguishable, whereas they must be treated as distinguishable in other approaches to quantum gravity (eg., LQG) in order to recover the Bekenstein-Hawking area-entropy law. However, different statistics will imply different behaviors of the black hole outside the thermodynamic limit. We illustrate this point by quantizing the Bañados-Teitelboim-Zanelli (BTZ) black hole, for which we argue that Bose condensation will occur leading to a "cold", stable remnant.
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
Yang, Huan; Lehner, Luis
2014-01-01
We show that rapidly-spinning black holes can display turbulent gravitational behavior which is mediated by a new type of parametric instability. This instability transfers energy from higher temporal and azimuthal spatial frequencies to lower frequencies--- a phenomenon reminiscent of the inverse energy cascade displayed by 2+1-dimensional turbulent fluids. Our finding reveals a path towards gravitational turbulence for perturbations of rapidly-spinning black holes, and provides the first evidence for gravitational turbulence in an asymptotically flat spacetime. Interestingly, this finding predicts observable gravitational wave signatures from such phenomena in black hole binaries with high spins and gives a gravitational description of turbulence relevant to the fluid-gravity duality.
Yang, Huan; Zimmerman, Aaron; Lehner, Luis
2015-02-01
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.
Aykutalp, Aycin; Spaans, Marco; Meijerink, Rowin
2014-01-01
In the last decade, the growth of supermassive black holes (SMBHs) has been intricately linked to galaxy formation and evolution and is a key ingredient in the assembly of galaxies. To investigate the origin of SMBHs, we perform cosmological simulations that target the direct collapse black hole (DCBH) seed formation scenario in the presence of two different strong Lyman-Werner (LW) background fields. These simulations include the X-ray irradiation from a central massive black hole (MBH), $\\rm{H}_2$ self-shielding and stellar feedback from metal-free and metal-enriched stars. We find in both simulations that local X-ray feedback induces metal-free star formation $\\sim 0.5$ Myr after the MBH forms. The MBH accretion rate reaches a maximum of $10^{-3}$ $M_{\\odot}$ yr$^{-1}$ in both simulations. However, the duty cycle differs which is derived to be $6\\%$ and $50\\%$ for high and low LW cases, respectively. The MBH in the high LW case grows only $\\sim 6\\%$ in 100 Myr compared to $16\\%$ in the low LW case. We find...
Black Holes Shed Light on Galaxy Formation
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.
Hennigar, Robie A; Tjoa, Erickson
2016-01-01
We present what we believe is the first example of a "$\\lambda$-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 AdS 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.
Hawking, Stephen W.
1995-01-01
One would expect spacetime to have a foam-like structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the non-trivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of $S^2\\times S^2$ and $K3$ bubbles. Comparison with the instantons for pair creation of black holes shows that the $S^2\\times S^2$ bubbles can be interpreted as closed loops of virtual black holes. It is ...
Aarseth, Sverre J
2007-01-01
We describe efforts over the last six years to implement regularization methods suitable for studying one or more interacting black holes by direct N-body simulations. Three different methods have been adapted to large-N systems: (i) Time-Transformed Leapfrog, (ii) Wheel-Spoke, and (iii) Algorithmic Regularization. These methods have been tried out with some success on GRAPE-type computers. Special emphasis has also been devoted to including post-Newtonian terms, with application to moderately massive black holes in stellar clusters. Some examples of simulations leading to coalescence by gravitational radiation will be presented to illustrate the practical usefulness of such methods.
Characterizing Black Hole Mergers
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.
Energy Technology Data Exchange (ETDEWEB)
Futterman, J.A.H.; Handler, F.A.; Matzner, R.A.
1987-01-01
This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging.
International Nuclear Information System (INIS)
This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging
Horndeski black hole geodesics
Tretyakova, D A
2016-01-01
We examine geodesics for the scalar-tensor black holes in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits may not be present within some model parameters range. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations. We also present a new (although very similar to those previously known) solution, which contains the orbits we expect from a compact object, admits regular scalar field at the horizon and and can fit into the known stability criteria.
Effective first law of thermodynamics of black holes with two horizons
Institute of Scientific and Technical Information of China (English)
Wei Yi-Huan
2009-01-01
For a black hole with two horizons, the effective entropy is assumed to be a linear combination of the two entropies of the outer and inner horizons. In terms of the effective thermodynamic quantities the effective Bekenstein-Smarr formula and the effective first law of thermodynamics are derived.
Schwinger Effect in (A)dS and Charged Black Hole
Kim, Sang Pyo
2015-01-01
In an (Anti-) de Sitter space and a charged black hole the Schwinger effect is either enhanced by the Hawking radiation or suppressed by the negative curvature. We use the contour integral method to calculate the production of charged pairs in the global (A)dS space. The charge emission from near-extremal black hole is found from the AdS geometry near the horizon and interpreted as the Schwinger effect in a Rindler space with the surface gravity for the acceleration as well as the Schwinger effect in AdS space.
Schwinger effect in (A)dS and charged black hole
Kim, Sang Pyo
In an Anti-de Sitter space and a charged black hole the Schwinger effect is either enhanced by the Hawking radiation or suppressed by the negative curvature. We use the contour integral method to calculate the production of charged pairs in the global (A)dS space. The charge emission from near-extremal black hole is found from the AdS geometry near the horizon and interpreted as the Schwinger effect in a Rindler space with the surface gravity for the acceleration as well as the Schwinger effect in AdS space.
Strong field effects on emission line profiles: Kerr black holes and warped accretion disks
Wang, Yan
2011-01-01
If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, ...
Horowitz, Gary T.; Maldacena, Juan
2003-01-01
We propose that in quantum gravity one needs to impose a final state boundary condition at black hole singularities. This resolves the apparent contradiction between string theory and semiclassical arguments over whether black hole evaporation is unitary.
Charged rotating black holes at large D
Tanabe, Kentaro
2016-01-01
We study odd dimensional charged equally rotating black holes in the Einstein-Maxwell theory with/without a cosmological constant by using the large D expansion method, where D is a spacetime dimension. Solving the Einstein-Maxwell equations in the 1/D expansion we obtain the large D effective equations for charged equally rotating black holes. The effective equations describe the nonlinear dynamics of charged equally rotating black holes. Especially the perturbation analysis of the effective...
5D Black Holes and Matrix Strings
Dijkgraaf, R.; Verlinde, E.; Verlinde, H.
1997-01-01
We derive the world-volume theory, the (non)-extremal entropy and background geometry of black holes and black strings constructed out of the NS IIA fivebrane within the framework of matrix theory. The CFT description of strings propagating in the black hole geometry arises as an effective field theory.
Energy Technology Data Exchange (ETDEWEB)
Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)
2011-09-22
A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.
The thermal effect of the Kerr black hole after considering the effect of evaporation
International Nuclear Information System (INIS)
After using the new generalized tortoise coordinate transformation, the Authors obtain the location of horizon and radiation temperature of an axis-symmetric Kerr black hole with coordinate (t, r) as variable, through directly solving the K-G equation near the event horizon. The result of the calculation indicates that on condition that the effect of evaporation is considered, the horizon surface of the Kerr black hole is an elliptic spherical surface which changes with time and the Hawking radiation temperature is not only relative to time but also to the azimuth. Further the results indicate that the Hawking radiation temperature can be regarded as a compensate effect under the time-scale transformation
Exact solutions of higher dimensional black holes
Tomizawa, Shinya
2011-01-01
We review exact solutions of black holes in higher dimensions, focusing on asymptotically flat black hole solutions and Kaluza-Klein type black hole solutions. We also summarize some properties which such black hole solutions reveal.
Directory of Open Access Journals (Sweden)
Arunima Patel
2013-01-01
Full Text Available Mobile Ad-Hoc Network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on continual basis. MANET has potential applications in very unpredictable and dynamic environments. Due to security vulnerabilities of the routing protocols, wireless ad-hoc networks are unprotected to attacks of the malicious nodes. One of these attacks is the Black Hole Attack. In this paper, we focus on analyzing the effect of active Black Hole Attack on one of famous reactive routing protocol AODV. Our aim is to simulate the effect of Black Hole Attack on AODV protocol using various performance metric parameters.
Black Hole Evaporation. A Survey
Benachenhou, Farid
1994-01-01
This thesis is a review of black hole evaporation with emphasis on recent results obtained for two dimensional black holes. First, the geometry of the most general stationary black hole in four dimensions is described and some classical quantities are defined. Then, a derivation of the spectrum of the radiation emitted during the evaporation is presented. In section four, a two dimensional model which has black hole solutions is introduced, the so-called CGHS model. These two dimensional blac...
Towards noncommutative quantum black holes
International Nuclear Information System (INIS)
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
Towards Noncommutative Quantum Black Holes
Lopez-Dominguez, J. C.; Obregon, O.; Ramirez, C.; Sabido, M.
2006-01-01
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.
Black Hole: The Interior Spacetime
Ong, Yen Chin
2016-01-01
The information loss paradox is often discussed from the perspective of the observers who stay outside of a black hole. However, the interior spacetime of a black hole can be rather nontrivial. We discuss the open problems regarding the volume of a black hole, and whether it plays any role in information storage. We also emphasize the importance of resolving the black hole singularity, if one were to resolve the information loss paradox.
Inclination and relativistic effects in the outburst evolution of black hole transients
Muñoz-Darias, T; Plant, D S; Ponti, G; Fender, R P; Dunn, R J H
2013-01-01
We have systematically studied the effect of the orbital inclination in the outburst evolution of black hole transients. We have included all the systems observed by the Rossi X-ray timing explorer in which the thermal, accretion disc component becomes strongly dominant at some point of the outburst. Inclination is found to modify the shape of the tracks that these systems display in the colour/luminosity diagrams traditionally used for their study. Black hole transients seen at low inclination reach softer spectra and their accretion discs look cooler than those observed closer to edge-on. This difference can be naturally explained by considering inclination dependent relativistic effects on accretion discs.
Analysis of Black Hole Effect and Prevention through IDS in MANET
Directory of Open Access Journals (Sweden)
Nisha
2013-10-01
Full Text Available A mobile ad hoc network (MANET is an autonomous network. It is a collection of mobile nodes that communicate with each other over wireless links. From last few years, the interest in the area of Mobile Adhoc Network (MANET is growing due to its practical applications and requirement of communication in mobile devices. In the comparison to wired or infrastructure-based wireless network, MANET is vulnerable to security attacks due to its fundamental characteristics, e.g., the open medium, dynamic network topology, lack of clear lines of defense, autonomous terminal, lack of centralized monitoring and management. There are various types of attacks in MANET which drops the network performance. Black hole attack is one of them. Ad hoc On-demand Distance Vector routing (AODV is a popular routing algorithm MANET. In this paper we investigated the effects of Black Hole attacks on the network performance. In our work we simulated black hole attacks in Network Simulator 2 (ns-2 and measured the throughput, PDF and routing load in the network withand without a black hole. We also proposed a solution against black hole attacks using intrusion detection system (IDS.
International Nuclear Information System (INIS)
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.
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.
Black Holes in Higher Dimensions
International Nuclear Information System (INIS)
In four space-time dimensions black holes of Einstein-Maxwell theory satisfy a number of theorems. In more than four space-time dimensions, however, some of the properties of black holes can change. In particular, uniqueness of black holes no longer holds. In five and more dimensions black rings arise. Thus in a certain region of the phase diagram there are three black objects with the same global charges present. Here we discuss properties of higher-dimensional vacuum and charged black holes, which possess a spherical horizon topology, and of vacuum and charged black rings, which have a ringlike horizon topology
Warped products and black holes
International Nuclear Information System (INIS)
We apply the warped product space-time scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstroem-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes
Warped products and black holes
Hong, S T
2005-01-01
We apply the warped product spacetime scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstr\\"om-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes.
Quantum Evaporation of Liouville Black Holes
Mann, R. B.
1993-01-01
The classical field equations of a Liouville field coupled to gravity in two spacetime dimensions are shown to have black hole solutions. Exact solutions are also obtained when quantum corrections due to back reaction effects are included, modifying both the ADM mass and the black hole entropy. The thermodynamic limit breaks down before evaporation of the black hole is complete, indicating that higher-loop effects must be included for a full description of the process. A scenario for the fina...
Disrupting Entanglement of Black Holes
Leichenauer, Stefan
2014-01-01
We study entanglement in thermofield double states of strongly coupled CFTs by analyzing two-sided Reissner-Nordstrom solutions in AdS. The central object of study is the mutual information between a pair of regions, one on each asymptotic boundary of the black hole. For large regions the mutual information is positive and for small ones it vanishes; we compute the critical length scale, which goes to infinity for extremal black holes, of the transition. We also generalize the butterfly effect of Shenker and Stanford to a wide class of charged black holes, showing that mutual information is disrupted upon perturbing the system and waiting for a time of order $\\log E/\\delta E$ in units of the temperature. We conjecture that the parametric form of this timescale is universal.
International Nuclear Information System (INIS)
In the last decade, the growth of supermassive black holes (SMBHs) has been intricately linked to galaxy formation and evolution and is a key ingredient in the assembly of galaxies. To investigate the origin of SMBHs, we perform cosmological simulations that target the direct collapse black hole seed formation scenario in the presence of two different strong Lyman-Werner (LW) background fields. These simulations include the X-ray irradiation from a central massive black hole (MBH), H2 self-shielding, and stellar feedback from metal-free and metal-enriched stars. We find in both simulations that local X-ray feedback induces metal-free star formation ∼0.5 Myr after the MBH forms. The MBH accretion rate reaches a maximum of 10–3 M ☉ yr–1 in both simulations. However, the duty cycle differs and is derived to be 6% and 50% for the high and low LW cases, respectively. The MBH in the high LW case grows only ∼6% in 100 Myr compared to 16% in the low LW case. We find that the maximum accretion rate is determined by the local gas thermodynamics, whereas the duty cycle is determined by the large-scale gas dynamics and gas reservoir. We conclude that radiative feedback from the central MBH plays an important role in star formation in the nuclear regions and stifling initial MBH growth relative to the typical Eddington rate argument, and that initial MBH growth might be affected by the local LW radiation field
Quantum Gravity Effects on the Tunneling Radiation of the Einstein-Maxwell-Dilaton-Axion Black Hole
Cheng, Tianhu; Ren, Ruyi; Chen, Deyou; Liu, Zixiang; Li, Guopin
2016-07-01
Taking into account effects of quantum gravity, we investigate the evaporation of an Einstein-Maxwell-Dilaton-Axion black hole. The corrected Hawking temperature is gotten respectively by the scalar particle's and the fermion's tunneling across the horizon. This temperature is lower than the original one derived by Hawking, which means quantum gravity effects slow down the rise of the temperature.
Control of black hole evaporation?
International Nuclear Information System (INIS)
Contradiction between Hawking's semi-classical arguments and the string theory on the evaporation of a black hole has been one of the most intriguing problems in fundamental physics. A final-state boundary condition inside the black hole was proposed by Horowitz and Maldacena to resolve this contradiction. We point out that the original Hawking effect can also be regarded as a separate boundary condition at the event horizon for this scenario. Here, we found that the change of the Hawking boundary condition may affect the information transfer from the initial collapsing matter to the outgoing Hawking radiation during the evaporation process and as a result the evaporation process itself, significantly
Black holes and warped spacetime
International Nuclear Information System (INIS)
Black holes (BHs) and their warping effect on spacetime are described, beginning with a discussion on stellar evolution that includes white dwarfs, supernovas and neutron stars. The structure of static, rotating, and electrically charged BHs are considered, as well as the general theory of relativity, quantum mechanics, the Einstein-Rosen bridge, and wormholes in spacetime. Attention is also given to gravitational lenses, various space geometries, quasars, Seyfert galaxies, supermassive black holes, the evaporation and particle emission of BHs, and primordial BHs, including their temperature and lifetime
Introduction to Black Hole Evaporation
Lambert, Pierre-Henry
2013-01-01
These lecture notes are an elementary and pedagogical introduction to the black hole evaporation, based on a lecture given by the author at the Ninth Modave Summer School in Mathematical Physics and are intended for PhD students. First, quantum field theory in curved spacetime is studied and tools needed for the remaining of the course are introduced. Then quantum field theory in Rindler spacetime in 1+1 dimensions and in the spacetime of a spherically collapsing star are considered, leading to Unruh and Hawking effects, respectively. Finally some consequences such as thermodynamics of black holes and information loss paradox are discussed.
Rotating Brane World Black Holes
Modgil, Moninder Singh; Panda, Sukanta; Sengupta, Gautam
2001-01-01
A five dimensional rotating black string in a Randall-Sundrum brane world is considered. The black string intercepts the three brane in a four dimensional rotating black hole. The geodesic equations and the asymptotics in this background are discussed.
Observational Evidence for Black Holes
Narayan, Ramesh; McClintock, Jeffrey E.
2013-01-01
Astronomers have discovered two populations of black holes: (i) stellar-mass black holes with masses in the range 5 to 30 solar masses, millions of which are present in each galaxy in the universe, and (ii) supermassive black holes with masses in the range 10^6 to 10^{10} solar masses, one each in the nucleus of every galaxy. There is strong circumstantial evidence that all these objects are true black holes with event horizons. The measured masses of supermassive black hole are strongly corr...
Statistical mechanics of black holes
International Nuclear Information System (INIS)
We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black-hole decay and of quantum coherence are also addressed
Primordial Black Holes in Phantom Cosmology
Jamil, Mubasher; Qadir, Asghar
2009-01-01
We investigate the effects of accretion of phantom energy onto primordial black holes. Since Hawking radiation and phantom energy accretion contribute to a {\\it decrease} of the mass of the black hole, the primordial black hole that would be expected to decay now due to the Hawking process would decay {\\it earlier} due to the inclusion of the phantom energy. Equivalently, to have the primordial black hole decay now it would have to be more massive initially. We find that the effect of the pha...
Effect of brane thickness on microscopic tidal-charged black holes
International Nuclear Information System (INIS)
We study the phenomenological implications stemming from the dependence of the tidal charge on the brane thickness L for the evaporation and decay of microscopic black holes. In general, the larger L, the longer are the black hole lifetimes and the greater their maximum mass for those cases in which the black hole can grow. In particular, we again find that tidal-charged black holes might live long enough to escape the detectors and even the gravitational field of the Earth, thus resulting in large amounts of missing energy. However, under no circumstances could TeV-scale black holes grow enough to enter the regime of Bondi accretion.
Primordial Structure of Massive Black Hole Clusters
Khlopov, Maxim Yu.; Rubin, Sergei G.; Sakharov, Alexander S.(Department of Physics, CERN, 1211, Geneva 23, Switzerland)
2004-01-01
We describe a mechanism of the primordial black holes formation that can explain the existence of a population of supermassive black holes in galactic bulges. The mechanism is based on the formation of black holes from closed domain walls. The origin of such domain walls could be a result of the evolution of an effectively massless scalar field during inflation. The initial non-equilibrium distribution of the scalar field imposed by background de-Sitter fluctuations gives rise to the spectrum...
Hawking emission from quantum gravity black holes
Nicolini, Piero; Winstanley, Elizabeth(Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom)
2011-01-01
We address the issue of modelling quantum gravity effects in the evaporation of higher dimensional black holes in order to go beyond the usual semi-classical approximation. After reviewing the existing six families of quantum gravity corrected black hole geometries, we focus our work on non-commutative geometry inspired black holes, which encode model independent characteristics, are unaffected by the quantum back reaction and have an analytical form compact enough for numerical simulations. ...
Prisons of light : black holes
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.
Point mass Cosmological Black Holes
Firouzjaee, Javad T
2016-01-01
Real black holes in the universe are located in the expanding accelerating background which are called the cosmological black holes. Hence, it is necessary to model these black holes in the cosmological background where the dark energy is the dominant energy. In this paper, we argue that most of the dynamical cosmological black holes can be modeled by point mass cosmological black holes. Considering the de Sitter background for the accelerating universe, we present the point mass cosmological background in the cosmological de Sitter space time. Our work also includes the point mass black holes which have charge and angular momentum. We study the mass, horizons, redshift structure and geodesics properties for these black holes.
Destroying Kerr-Sen black holes
Siahaan, Haryanto M.
2016-03-01
By neglecting the self-force, self-energy, and radiative effects, it has been shown that an extremal or near-extremal Kerr-Newman black hole can turn into a naked singularity when it captures charged and spinning massive particles. A straightforward question then arises: do charged and rotating black holes in string theory possess the same property? In this paper we apply Wald's gedanken experiment, in his study on the possibility of destroying extremal Kerr-Newman black holes, to the case of (near-)extremal Kerr-Sen black holes. We find that feeding a test particle into a (near-)extremal Kerr-Sen black hole could lead to a violation of the extremal bound for the black hole.
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
Energy Technology Data Exchange (ETDEWEB)
Anacleto, M.A., E-mail: anacleto@df.ufcg.edu.br; Brito, F.A., E-mail: fabrito@df.ufcg.edu.br; Passos, E., E-mail: passos@df.ufcg.edu.br
2015-04-09
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity.
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
Directory of Open Access Journals (Sweden)
M.A. Anacleto
2015-04-01
Full Text Available In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov–Bohm effect due to spacetime noncommutativity.
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
International Nuclear Information System (INIS)
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity
Gravitational Aharonov-Bohm effect due to noncommutative BTZ black hole
Anacleto, M A; Passos, E
2014-01-01
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity
Gravitational Aharonov–Bohm effect due to noncommutative BTZ black hole
M.A. Anacleto; Brito, F. A.; E. Passos
2015-01-01
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov–Bohm effect due to spacetime noncommutativity.
Gravitational Aharonov-Bohm effect due to noncommutative BTZ black hole
Anacleto, M. A.; Brito, F. A.; Passos, E.
2015-04-01
In this paper we consider the scattering of massless planar scalar waves by a noncommutative BTZ black hole. We compute the differential cross section via the partial wave approach, and we mainly show that the scattering of planar waves leads to a modified Aharonov-Bohm effect due to spacetime noncommutativity.
Chamblin, A; Reall, H S
2000-01-01
Gravitational collapse of matter trapped on a brane will produce a black hole on the brane. We discuss such black holes in the models of Randall and Sundrum where our universe is viewed as a domain wall in five dimensional anti-de Sitter space. We present evidence that a non-rotating uncharged black hole on the domain wall is described by a ``black cigar'' solution in five dimensions.
Chamblin, A.; Hawking, S. W.; Reall, H. S.
2000-03-01
Gravitational collapse of matter trapped on a brane will produce a black hole on the brane. We discuss such black holes in the models of Randall and Sundrum where our universe is viewed as a domain wall in five-dimensional anti-de Sitter space. We present evidence that a non-rotating uncharged black hole on the domain wall is described by a ``black cigar'' solution in five dimensions.
Black Holes in Higher Dimensions
Directory of Open Access Journals (Sweden)
Reall Harvey S.
2008-09-01
Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.
Bena, Iosif; Vercnocke, Bert
2012-01-01
We establish the relation between the structure governing supersymmetric and non-supersymmetric four- and five-dimensional black holes and multicenter solutions and Calabi-Yau flux compactifications of M-theory and type IIB string theory. We find that the known BPS and almost-BPS multicenter black hole solutions can be interpreted as GKP compactifications with (2,1) and (0,3) imaginary self-dual flux. We also show that the most general GKP compactification leads to new classes of BPS and non-BPS multicenter solutions. We explore how these solutions fit into N=2 truncations, and elucidate how supersymmetry becomes camouflaged. As a necessary tool in our exploration we show how the fields in the largest N=2 truncation fit inside the six-torus compactification of eleven-dimensional supergravity.
Clement, María E Gabach
2015-01-01
It is well known that celestial bodies tend to be spherical due to gravity and that rotation produces deviations from this sphericity. We discuss what is known and expected about the shape of black holes' horizons from their formation to their final, stationary state. We present some recent results showing that black hole rotation indeed manifests in the widening of their central regions, limits their global shapes and enforces their whole geometry to be close to the extreme Kerr horizon geometry at almost maximal rotation speed. The results depend only on the horizon area and angular momentum. In particular they are entirely independent of the surrounding geometry of the spacetime and of the presence of matter satisfying the strong energy condition. We also discuss the the relation of this result with the Hoop conjecture.
Destroying black holes with test bodies
Energy Technology Data Exchange (ETDEWEB)
Jacobson, Ted [Center for Fundamental Physics, University of Maryland, College Park, MD 20742-4111 (United States); Sotiriou, Thomas P, E-mail: jacobson@umd.ed, E-mail: T.Sotiriou@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2010-04-01
If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.
Destroying black holes with test bodies
International Nuclear Information System (INIS)
If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.
Microscopic theory of black hole superradiance
Óscar J.C. Dias(CAMGSD, Departamento de Matemática and LARSyS, Instituto Superior Técnico, 1049-001 Lisboa, Portugal); Emparan García de Salazar, Roberto A.; Maccarrone, Alessandro
2008-01-01
We study how black hole superradiance appears in string microscopic models of rotating black holes. In order to disentangle superradiance from finite-temperature effects, we consider an extremal, rotating D1-D5-P black hole that has an ergosphere and is not supersymmetric. We explain how the microscopic dual accounts for the superradiant ergosphere of this black hole. The bound 0< omega < m Omega_H on superradiant mode frequencies is argued to be a consequence of Fermi-Dirac statistics for th...
Light geodesics near an evaporating black hole
Energy Technology Data Exchange (ETDEWEB)
Guerreiro, Thiago, E-mail: thiago.barbosa@unige.ch; Monteiro, Fernando, E-mail: fernando.monteiro@unige.ch
2015-10-16
Quantum effects imply that an infalling observer cannot cross the event horizon of an evaporating black hole, even in her proper time. The Penrose diagram of an evaporating black hole is different from the one usually reported in the literature. We show that before the observer can cross the horizon the black hole disappears. Possible observational consequences are discussed. - Highlights: • We calculate the in-falling light geodesics in an evaporating black hole. • For our calculation we use a non-static metric called Vaydia metric. • We show that in-falling light cannot cross the event horizon. • In this case there is no information paradox.
Light geodesics near an evaporating black hole
International Nuclear Information System (INIS)
Quantum effects imply that an infalling observer cannot cross the event horizon of an evaporating black hole, even in her proper time. The Penrose diagram of an evaporating black hole is different from the one usually reported in the literature. We show that before the observer can cross the horizon the black hole disappears. Possible observational consequences are discussed. - Highlights: • We calculate the in-falling light geodesics in an evaporating black hole. • For our calculation we use a non-static metric called Vaydia metric. • We show that in-falling light cannot cross the event horizon. • In this case there is no information paradox
Bastos, C; Dias, N C; Prata, J N
2010-01-01
One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity regime and it is shown that the wave function vanishes in this limit.
Infinitely Coloured Black Holes
Mavromatos, Nick E.; Winstanley, Elizabeth(Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom)
1999-01-01
We formulate the field equations for $SU(\\infty)$ Einstein-Yang-Mills theory, and find spherically symmetric black-hole solutions. This model may be motivated by string theory considerations, given the enormous gauge symmetries which characterize string theory. The solutions simplify considerably in the presence of a negative cosmological constant, particularly for the limiting cases of a very large cosmological constant or very small gauge field. The situation of an arbitrarily small gauge f...
International Nuclear Information System (INIS)
This book is about the life and work of Stephen Hawking. It traces the development of his theories about the universe and particularly black holes, in a biographical context. Hawking's lecture 'Is the end in sight for theoretical physics' is presented as an appendix. In this, he discusses the possibility of achieving a complete, consistent and unified theory of the physical interactions which would describe all possible observations. (U.K.)
Roberto Casadio(INFN, Bologna); Andrea Giugno; Octavian Micu; Alessio Orlandi
2015-01-01
We review some features of Bose–Einstein condensate (BEC) models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractiv...
Helfer, Adam D
2011-01-01
I review elements of the foundations of black-hole theory with attention to problematic issues, and describe some techniques which either seem to help with the difficulties or at least investigate their scope. The definition of black holes via event horizons has been problematic because it depends on knowing the global structure of space-time; often attempts to avoid this (e.g. apparent horizons) require knowledge of the interior geometry. I suggest studying instead the holonomy relating the exterior neighborhood of the incipient horizon to the regime of distant observers; at least in the spherically symmetric case, this holonomy will develop certain universal features, in principle observable from signals emitted from infalling objects. I discuss the theory of quantum fields in curved space-time, and the difficulties with Hawking's prediction of black-hole radiation. I then show that the usual, very natural, theory of quantum fields in curved space-time runs into difficulties when applied to measurement prob...
(Anti-)Evaporation of Schwarzschild-de Sitter Black Holes
Bousso, Raphael; Hawking, Stephen
1997-01-01
We study the quantum evolution of black holes immersed in a de Sitter background space. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. Our model includes the one-loop effective action in the s-wave and large N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, we find that nearly maximal quantum Schwarzschild-de Sitter black holes anti-evapor...
Aharonov-Bohm effect for a fermion field in the acoustic black hole background
Anacleto, M A; Mohammadi, A; Passos, E
2016-01-01
In this paper we consider the dynamics of a massive spinor field in the background of the acoustic black hole spacetime and then compute the differential cross section through the use of the partial wave approach. We show that an effect similar to the gravitational Aharonov-Bohm effect occurs for massive fermion fields moving in this effective metric. We discuss the limiting cases and compare the results with the bosonic case.
Evaporation of charged black holes near extremality
Fabbri, A; Navarro, D. J.; Navarro-Salas, J.
2000-01-01
The AdS_2\\timesS^2 geometry of near-extremal Reissner-Nordstrom black holes can be described by an effective solvable model which allows to follow analytically the evaporation process including the backreaction. We find that an infinite amount of time is required for the black hole to decay to extremality.
Black hole complementarity: The inside view
Energy Technology Data Exchange (ETDEWEB)
Lowe, David A., E-mail: lowe@brown.edu [Department of Physics, Brown University, Providence, RI 02912 (United States); Thorlacius, Larus, E-mail: larus@nordita.org [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden); University of Iceland, Science Institute, Dunhaga 3, IS-107 Reykjavik (Iceland)
2014-10-07
Within the framework of black hole complementarity, a proposal is made for an approximate interior effective field theory description. For generic correlators of local operators on generic black hole states, it agrees with the exact exterior description in a region of overlapping validity, up to corrections that are too small to be measured by typical infalling observers.
Black hole complementarity: The inside view
Directory of Open Access Journals (Sweden)
David A. Lowe
2014-10-01
Full Text Available Within the framework of black hole complementarity, a proposal is made for an approximate interior effective field theory description. For generic correlators of local operators on generic black hole states, it agrees with the exact exterior description in a region of overlapping validity, up to corrections that are too small to be measured by typical infalling observers.
Black Holes as Dark Matter Annihilation Boosters
Mattia FornasaINFN Padova, IAP; Gianfranco Bertone(IAP)
2007-01-01
We review the consequences of the growth and evolution of Black Holes on the distribution of stars and Dark Matter (DM) around them. We focus in particular on Supermassive and Intermediate Mass Black Holes, and discuss under what circumstances they can lead to significant overdensities in the surrounding distribution of DM, thus effectively acting as DM annihilation boosters.
Black hole complementarity: The inside view
International Nuclear Information System (INIS)
Within the framework of black hole complementarity, a proposal is made for an approximate interior effective field theory description. For generic correlators of local operators on generic black hole states, it agrees with the exact exterior description in a region of overlapping validity, up to corrections that are too small to be measured by typical infalling observers
Stimulated emission and black holes
International Nuclear Information System (INIS)
The probability of a black hole emitting m particles when n particles are incident on the black hole was first derived by Bekenstein and Meisels, and later, using a different method, by Panangaden and Wald. In another paper by Bekenstein, it was argued that black holes should have stimulated emission in all modes including the nonsuperradiant ones. In this paper, we use a model based on quantum field theory. We show that Bose-Einstein statistics enhances the probability for particles to scatter in the same direction. We also prove that a black hole is equivalent to a perfect blackbody surrounded by a mirror. In our model, the black hole does not exhibit stimulated emission in nonsuperradiant modes. We also compare the black hole to a gray body
Small black holes on cylinders
International Nuclear Information System (INIS)
We find the metric of small black holes on cylinders, i.e. neutral and static black holes with a small mass in d-dimensional Minkowski space times a circle. The metric is found using an ansatz for black holes on cylinders proposed in J. High Energy Phys. 05, 032 (2002). We use the new metric to compute corrections to the thermodynamics which is seen to deviate from that of the (d+1)-dimensional Schwarzschild black hole. Moreover, we compute the leading correction to the relative binding energy which is found to be non-zero. We discuss the consequences of these results for the general understanding of black holes and we connect the results to the phase structure of black holes and strings on cylinders
Effect of vacuum energy on evolution of primordial black holes in Einstein gravity
International Nuclear Information System (INIS)
We study the evolution of primordial black holes by considering present universe is no more matter dominated rather vacuum energy dominated. We also consider the accretion of radiation, matter and vacuum energy during respective dominance period. In this scenario, we found that radiation accretion efficiency should be less than 0.366 and accretion rate is much larger than previous analysis by Nayak et al. (2009) . Thus here primordial black holes live longer than previous works Nayak and Singh (2011). Again matter accretion slightly increases the mass and lifetime of primordial black holes. However, the vacuum energy accretion is slightly complicated one, where accretion is possible only up to a critical time. If a primordial black hole lives beyond critical time, then its' lifespan increases due to vacuum energy accretion. But for presently evaporating primordial black holes, critical time comes much later than their evaporating time and thus vacuum energy could not affect those primordial black holes.
Information Storage in Black Holes
Maia, M. D.
2005-01-01
The information loss paradox for Schwarzschild black holes is examined, using the ADS/CFT correspondence extended to the $M_6 (4,2)$ bulk. It is found that the only option compatible with the preservation of the quantum unitarity is when a regular remnant region of the black hole survives to the black hole evaporation process, where information can be stored and eventually retrieved.
Origin of supermassive black holes
Dokuchaev, V. I.; Eroshenko, Yu. N.; Rubin, S. G.
2007-01-01
The origin of supermassive black holes in the galactic nuclei is quite uncertain in spite of extensive set of observational data. We review the known scenarios of galactic and cosmological formation of supermassive black holes. The common drawback of galactic scenarios is a lack of time and shortage of matter supply for building the supermassive black holes in all galaxies by means of accretion and merging. The cosmological scenarios are only fragmentarily developed but propose and pretend to...
International Nuclear Information System (INIS)
In this talk, I present and discuss a number of attempts to construct black hole solutions in models with Warped Extra Dimensions. Then, a contact is made with models with Large Extra Dimensions, where black-hole solutions are easily constructed - here the focus will be on the properties of microscopic black holes and the possibility of using phenomena associated with them, such as the emission of Hawking radiation, to discover fundamental properties of our spacetime.
Hod, Shahar
2016-06-01
It has recently been suggested (S.B. Giddings (2016) [2]) that the Hawking black-hole radiation spectrum originates from an effective quantum "atmosphere' which extends well outside the black-hole horizon. In particular, comparing the Hawking radiation power of a (3 + 1)-dimensional Schwarzschild black hole of horizon radius rH with the familiar Stefan-Boltzmann radiation power of a (3 + 1)-dimensional flat space perfect blackbody emitter, Giddings concluded that the source of the Hawking semi-classical black-hole radiation is a quantum region outside the Schwarzschild black-hole horizon whose effective radius rA is characterized by the relation Δr ≡rA -rH ∼rH. It is of considerable physical interest to test the general validity of Giddings's intriguing conclusion. To this end, we study the Hawking radiation of (D + 1)-dimensional Schwarzschild black holes. We find that the dimensionless radii rA /rH which characterize the black-hole quantum atmospheres, as determined from the Hawking black-hole radiation power and the (D + 1)-dimensional Stefan-Boltzmann radiation law, are a decreasing function of the number D + 1 of spacetime dimensions. In particular, it is shown that radiating (D + 1)-dimensional Schwarzschild black holes are characterized by the relation (rA -rH) /rH ≪ 1 in the large D ≫ 1 regime. Our results therefore suggest that, at least in some physical cases, the Hawking emission spectrum originates from quantum excitations very near the black-hole horizon.
The Effect of Gravitational Recoil on Black Holes Forming in a Hierarchical Universe
Libeskind, N. I.; S. Cole; Frenk, C.S.; Helly, J. C.
2005-01-01
Galactic bulges are known to harbour central black holes whose mass is tightly correlated with the stellar mass and velocity dispersion of the bulge. In a hierarchical universe, mergers of subgalactic units are accompanied by the amalgamation of bulges and the likely coalescence of galactocentric black holes. In these mergers, the beaming of gravitational radiation during the plunge phase of the black hole collision can impart a linear momentum kick or ``gravitational recoil'' to the remnant....
Quantum Non-thermal Effect From Kerr-Newman Black Hole
Institute of Scientific and Technical Information of China (English)
HAN Yi-Wen
2009-01-01
We present a short and direct derivation of Hawking radiation by using the Damour-Ruffini method, as taking into account the self-gravitational interaction from the Kerr-Newman black hole, It is found that the radiation is not exactly thermal, and because the derivation obey conservation laws, the non-thermal Hawking radiation can carry information from the black hole. So it can be used to explain the black hole information paradox, and the process satisfies unitary.
Effect of quintessence on the energy of the Reissner-Nordstrom black hole
Hussain, Ibrar; Ali, Sajid
2014-01-01
The energy content of the Reissner-Nordstrom black hole surrounded by quintessence is investigated using approximate Lie symmetry methods. It is mainly done by assuming mass and charge of the black hole as small quantities ($\\epsilon$), and by retaining its second power in the perturbed geodesic equations for such black hole while neglecting its higher powers. Due to the presence of trivial second-order approximate Lie symmetries of these perturbed geodesic equations, a rescaling of the geode...
Casadio, Roberto; Giugno, Andrea; Micu, Octavian; Orlandi, Alessio
2015-10-01
We review some features of BEC models of black holes obtained by means of the HWF formalism. We consider the KG equation for a toy graviton field coupled to a static matter current in spherical symmetry. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. An attractive self-interaction is needed for bound states to form, so that (approximately) one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The HWF is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons), in agreement with semiclassical calculations and different from a single very massive particle. The spectrum contains a discrete ground state of energy $m$ (the bosons forming the black hole), and a continuous spectrum with energy $\\omega > m$ (representing the Hawking radiation and modelled with a Planckian distribution at the expected Hawking temperature). The $N$-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. The partition function is then found to yield the usual area law for the entropy, with a logarithmic correction related with the Hawking component. The backreaction of modes with $\\omega > m$ is also shown to reduce the Hawking flux and the evaporation properly stops for vanishing mass.
Caged black holes: Black holes in compactified spacetimes. I. Theory
International Nuclear Information System (INIS)
In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes
Statistical Hair on Black Holes
International Nuclear Information System (INIS)
The Bekenstein-Hawking entropy for certain BPS-saturated black holes in string theory has recently been derived by counting internal black hole microstates at weak coupling. We argue that the black hole microstate can be measured by interference experiments even in the strong coupling region where there is clearly an event horizon. Extracting information which is naively behind the event horizon is possible due to the existence of statistical quantum hair carried by the black hole. This quantum hair arises from the arbitrarily large number of discrete gauge symmetries present in string theory. copyright 1996 The American Physical Society
How black holes saved relativity
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.
Thermodynamics of Accelerating Black Holes
Appels, Michael; Kubiznak, David
2016-01-01
We address a long-standing problem of describing the thermodynamics of a charged 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.
Directory of Open Access Journals (Sweden)
I. Cabrera-Munguia
2015-04-01
Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.
Directory of Open Access Journals (Sweden)
Armen Yeranyan
2008-10-01
Full Text Available The general solutions of the radial attractor flow equations for extremal black holes, both for non-BPS with non-vanishing central charge Z and for Z = 0, are obtained for the so-called stu model, the minimal rank-3 N = 2 symmetric supergravity in d = 4 space-time dimensions. Comparisons with previous partial results, as well as the fake supergravity (first order formalism and an analysis of the marginal stability of corresponding D-brane configurations, are given.
Bastos, C.; Bertolami, O.; Dias, N. C.; Prata, J. N.
2010-04-01
One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, η. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.
Energy Technology Data Exchange (ETDEWEB)
Bastos, C; Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Dias, N C; Prata, J N, E-mail: cbastos@fisica.ist.utl.p, E-mail: orfeu@cosmos.ist.utl.p, E-mail: ncdias@mail.telepac.p, E-mail: joao.prata@mail.telepac.p [Departamento de Matematica, Universidade Lusofona de Humanidades e Tecnologias, Avenida Campo Grande, 376, 1749-024 Lisboa (Portugal)
2010-04-01
One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, {eta}. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.
International Nuclear Information System (INIS)
One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, η. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.
Holographic Black Hole Chemistry
Karch, Andreas
2015-01-01
Thermodynamic quantities associated with black holes in Anti-de Sitter space obey an interesting identity when the cosmological constant is included as one of the dynamical variables, the generalized Smarr relation. We show that this relation can easily be understood from the point of view of the dual holographic field theory. It amounts to the simple statement that the extensive thermodynamic quantities of a large $N$ gauge theory only depend on the number of colors, $N$, via an overall factor of $N^2$.
Black Hole Thermodynamics Based on Unitary Evolutions
Feng, Yu-Lei
2015-01-01
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 $S_{BH}$ cannot be a Boltzmann or thermal entropy. To confirm this statement, we show that the original black hole's "first law" cannot 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 in a unitary manner effectively, 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 in Asymptotically Safe Gravity
Saueressig, Frank; D'Odorico, Giulio; Vidotto, Francesca
2015-01-01
Black holes are among the most fascinating objects populating our universe. Their characteristic features, encompassing spacetime singularities, event horizons, and black hole thermodynamics, provide a rich testing ground for quantum gravity ideas. In this note we observe that the renormalization group improved Schwarzschild black holes constructed by Bonanno and Reuter within Weinberg's asymptotic safety program constitute a prototypical example of a Hayward geometry used to model non-singular black holes within quantum gravity phenomenology. Moreover, they share many features of a Planck star: their effective geometry naturally incorporates the one-loop corrections found in the effective field theory framework, their Kretschmann scalar is bounded, and the black hole singularity is replaced by a regular de Sitter patch. The role of the cosmological constant in the renormalization group improvement process is briefly discussed.
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
International Nuclear Information System (INIS)
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. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Corda, Christian [Institute for Theoretical Physics and Advanced Mathematics (IFM) Einstein-Galilei, Prato (Italy); Istituto Universitario di Ricerca ' ' Santa Rita' ' , Prato (Italy); International Institute for Applicable Mathematics and Information Sciences (IIAMIS), Hyderabad (India)
2013-12-15
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. (orig.)
Quasinormal modes of extremal black holes
Richartz, Maurício
2016-03-01
The continued fraction method (also known as Leaver's method) is one of the most effective techniques used to determine the quasinormal modes of a black hole. For extremal black holes, however, the method does not work (since, in such a case, the event horizon is an irregular singular point of the associated wave equation). Fortunately, there exists a modified version of the method, devised by Onozawa et al. [Phys. Rev. D 53, 7033 (1996)], which works for neutral massless fields around an extremal Reissner-Nordström black hole. In this paper, we generalize the ideas of Onozawa et al. to charged massless perturbations around an extremal Reissner-Nordström black hole and to neutral massless perturbations around an extremal Kerr black hole. In particular, the existence of damped modes is analyzed in detail. Similarities and differences between the results of the original continued fraction method for near extremal black holes and the results of the new continued fraction method for extremal black holes are discussed. Mode stability of extremal black holes is also investigated.
Measuring the black hole parameters from space
International Nuclear Information System (INIS)
Recently Holz and Wheeler considered a very attracting possibility to detect retro-MACHOs, i.e., retro-images of the Sun by a Schwarzschild black hole. In this paper we discuss glories (mirages) formed near rapidly rotating Kerr black hole horizons and propose a procedure to measure masses and rotation parameters analyzing these forms of mirages. In some sense that is a manifestation of gravitational lens effect in the strong gravitational field near black hole horizon and a generalization of the retro-gravitational lens phenomenon. We analyze the case of a Kerr black hole rotating at arbitrary speed for some selected positions of a distant observer with respect to the equatorial plane of a Kerr black hole. Some time ago suggested to search shadows at the Galactic Center. In this paper we present the boundaries for shadows. We also propose to use future radio interferometer RADIOASTRON facilities to measure shapes of mirages (glories) and to evaluate the black hole spin as a function of the position angle of a distant observer. We propose also a procedure to measure a black hole charge with future space missions. Keywords: black hole physics, gravitational lenses, microlensing. (authors)
Chandra Catches "Piranha" Black Holes
2007-07-01
had good evidence until now," said co-author Paul Martini, also of OSU. "This can help solve a couple of mysteries about galaxy clusters." One mystery is why there are so many blue, star-forming galaxies in young, distant clusters and fewer in nearby, older clusters. AGN are believed to expel or destroy cool gas in their host galaxy through powerful eruptions from the black hole. This may stifle star formation and the blue, massive stars will then gradually die off, leaving behind only the old, redder stars. This process takes about a billion years or more to take place, so a dearth of star-forming galaxies is only noticeable for older clusters. The process that sets the temperature of the hot gas in clusters when they form is also an open question. These new results suggest that even more AGN may have been present when most clusters were forming about ten billion years ago. Early heating of a cluster by large numbers of AGN can have a significant, long-lasting effect on the structure of a cluster by "puffing up" the gas. "In a few nearby clusters we've seen evidence for huge eruptions generated by supermassive black holes. But this is sedate compared to what might be going on in younger clusters," said Eastman. These results appeared in the July 20th issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov
Spin-Spin Effects in Models of Binary Black Hole Systems
Hawley, Scott; Matzner, Richard; Thompson, Lindsey
2012-03-01
We have implemented a parallel multigrid solver, to solve the initial data problem for 3 + 1 General Relativity. This involves solution of elliptic equations derived from the Hamiltonian and the momentum constraints. We use the conformal transverse-traceless method of York and collaborators which consists of a conformal decomposition with a scalar that adjusts the metric, and a vector potential that adjusts the longitudinal components of the extrinsic curvature. The constraint equations are then solved for these quantities such that the complete solution fully satisfies the constraints. We apply this technique to compare with theoretical expectations for the spin-orientation- and separation-dependence in the case of spinning interacting (but not orbiting) black holes. We write out a formula for the effect of the spin-spin interaction which includes a result of Wald as well as additional effect due to the rotation of the mass quadrupole moment of a spinning black hole.
Casadio, Roberto; Micu, Octavian; Orlandi, Alessio
2015-01-01
We review some features of BEC models of black holes obtained by means of the HWF formalism. We consider the KG equation for a toy graviton field coupled to a static matter current in spherical symmetry. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. An attractive self-interaction is needed for bound states to form, so that (approximately) one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The HWF is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons), in agreement with semiclassical calculations and different from a single very massive particle. The spectrum contains a...
Hawking, Stephen William
1996-01-01
One would expect spacetime to have a foam-like structure on the Planck scale with a very high topology. If spacetime is simply connected (which is assumed in this paper), the non-trivial homology occurs in dimension two, and spacetime can be regarded as being essentially the topological sum of S^2\\times S^2 and K3 bubbles. Comparison with the instantons for pair creation of black holes shows that the S^2\\times S^2 bubbles can be interpreted as closed loops of virtual black holes. It is shown that scattering in such topological fluctuations leads to loss of quantum coherence, or in other words, to a superscattering matrix \\ that does not factorise into an S matrix and its adjoint. This loss of quantum coherence is very small at low energies for everything except scalar fields, leading to the prediction that we may never observe the Higgs particle. Another possible observational consequence may be that the \\theta angle of QCD is zero without having to invoke the problematical existence of a light axion. The pic...
Black hole thermodynamical entropy
Energy Technology Data Exchange (ETDEWEB)
Tsallis, Constantino [Centro Brasileiro de Pesquisas Fisicas and National Institute of Science and Technology for Complex Systems, Rio de Janeiro, RJ (Brazil); Santa Fe Institute, Santa Fe, NM (United States); Cirto, Leonardo J.L. [Centro Brasileiro de Pesquisas Fisicas and National Institute of Science and Technology for Complex Systems, Rio de Janeiro, RJ (Brazil)
2013-07-15
As early as 1902, Gibbs pointed out that systems whose partition function diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs (BG) theory. Consistently, since the pioneering Bekenstein-Hawking results, physically meaningful evidence (e.g., the holographic principle) has accumulated that the BG entropy S{sub BG} of a (3+1) black hole is proportional to its area L{sup 2} (L being a characteristic linear length), and not to its volume L{sup 3}. Similarly it exists the area law, so named because, for a wide class of strongly quantum-entangled d-dimensional systems, S{sub BG} is proportional to lnL if d=1, and to L{sup d-1} if d>1, instead of being proportional to L{sup d} (d {>=} 1). These results violate the extensivity of the thermodynamical entropy of a d-dimensional system. This thermodynamical inconsistency disappears if we realize that the thermodynamical entropy of such nonstandard systems is not to be identified with the BG additive entropy but with appropriately generalized nonadditive entropies. Indeed, the celebrated usefulness of the BG entropy is founded on hypothesis such as relatively weak probabilistic correlations (and their connections to ergodicity, which by no means can be assumed as a general rule of nature). Here we introduce a generalized entropy which, for the Schwarzschild black hole and the area law, can solve the thermodynamic puzzle. (orig.)
Kerr black holes are not fragile
Energy Technology Data Exchange (ETDEWEB)
McInnes, Brett, E-mail: matmcinn@nus.edu.sg [Centro de Estudios Cientificos (CECs), Valdivia (Chile); National University of Singapore (Singapore)
2012-04-21
Certain AdS black holes are 'fragile', in the sense that, if they are deformed excessively, they become unstable to a fundamental non-perturbative stringy effect analogous to Schwinger pair-production [of branes]. Near-extremal topologically spherical AdS-Kerr black holes, which are natural candidates for string-theoretic models of the very rapidly rotating black holes that have actually been observed to exist, do represent a very drastic deformation of the AdS-Schwarzschild geometry. One therefore has strong reason to fear that these objects might be 'fragile', which in turn could mean that asymptotically flat rapidly rotating black holes might be fragile in string theory. Here we show that this does not happen: despite the severe deformation implied by near-extremal angular momenta, brane pair-production around topologically spherical AdS-Kerr-Newman black holes is always suppressed.
Black hole relics in large extra dimensions
International Nuclear Information System (INIS)
Recent calculations applying statistical mechanics indicate that in a setting with compactified large extra dimensions a black hole might evolve into a (quasi-)stable state with mass close to the new fundamental scale Mf. Black holes and therefore their relics might be produced at the LHC in the case of extra-dimensional topologies. In this energy regime, Hawking's evaporation scenario is modified due to energy conservation and quantum effects. We reanalyse the evaporation of small black holes including the quantisation of the emitted radiation due to the finite surface of the black hole. It is found that observable stable black hole relics with masses ∼1-3Mf would form which could be identified by a delayed single jet with a corresponding hard momentum kick to the relic and by ionisation, e.g., in a TPC
Black hole thermodynamics in MOdified Gravity (MOG)
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.
Nonthermal correction to black hole spectroscopy
International Nuclear Information System (INIS)
Area spectrum of black holes has been obtained via various methods such as quasinormal modes, adiabatic invariance and angular momentum. Among those methods, calculations were done by assuming black holes in thermal equilibrium. Nevertheless, black holes in the asymptotically flat space usually have a negative specific heat and therefore tend to stay away from thermal equilibrium. Even for black holes with a positive specific heat, the temperature may still not be well defined in the process of radiation, due to the back reaction of a decreasing mass. With respect to these facts, it is very likely that Hawking radiation is nonthermal and the area spectrum is no longer equidistant. In this note, we would like to illustrate how the area spectrum of black holes is corrected by this nonthermal effect. (orig.)
Shuang-Qing, W; Shuang-Qing, Wu; Mu-Lin, Yan
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated by using a method of the generalized tortoise coordinate transformation. Both the location and temperature of the event horizon depend on the time and on the angles. They coincide with previous results, but the thermal radiation spectrum of massless spinor particles displays a kind of spin-acceleration coupling effect.
Institute of Scientific and Technical Information of China (English)
吴双清; 闫沐霖
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated using a method of the generalized tortoise coordinate transformation.Both the location and temperature of the event horizon depend on the time and on the angles.They are in agreement with the previous results,but thethermal radiation spectrum of massless spinor particles displays a type of spin-acceleration coupling effect.
Boundary Effects on the Thermodynamics of Quantum Fields Near a Black Hole
Akant, Levent; Debir, Birses; Ertugrul, Emine
2015-01-01
We study the thermodynamics of a quantum field in a spherical shell around a static black hole. We implement brick wall regularization by imposing Dirichlet boundary conditions on the field at the boundaries and analyze their effects on the free energy and the entropy. We also consider the possibility of using Neumann boundary conditions. We examine both bosonic and fermionic fields in Schwarzschild, Reissner-Nordstr\\"om (RN), extreme RN, and dilatonic backgrounds. We show that the horizon di...
Domination of black hole accretion in brane cosmology
A. S. Majumdar
2002-01-01
We consider the evolution of primordial black holes formed during the high energy phase of the braneworld scenario. We show that the effect of accretion from the surrounding radiation bath is dominant compared to evaporation for such black holes. This feature lasts till the onset of matter (or black hole) domination of the total energy density which could occur either in the high energy phase or later. We find that the black hole evaporation times could be significantly large even for black h...
Primordial braneworld black holes: significant enhancement of lifetimes through accretion
A. S. Majumdar
2003-01-01
The Randall-Sundrum (RS-II) braneworld cosmological model with a fraction of the total energy density in primordial black holes is considered. Due to their 5-d geometry these black holes undergo modified Hawking evaporation. It is shown that during the high energy regime accretion from the surrounding radiation bath is dominant compared to evaporation. This effect increases the mass of the black holes till the onset of matter (or black hole) domination of the total energy density. Thus black ...
Area spectrum of slowly rotating black holes
Myung, Yun Soo
2010-01-01
We investigate the area spectrum for rotating black holes which are Kerr and BTZ black holes. For slowly rotating black holes, we use the Maggiore's idea combined with Kunstatter's method to derive their area spectra, which are equally spaced.
What, no black hole evaporation
International Nuclear Information System (INIS)
Tipler has claimed that the inward flux of negative energy across the horizon which (according to the semi-classical approximation) accompanies the evaporation of a black hole would cause a solar mass black hole to evaporate in less than a second. It is shown that this claim is in error. (orig.)
Nonlinear Electrodynamics and black holes
Breton, N; Breton, Nora; Garcia-Salcedo, Ricardo
2007-01-01
It is addressed the issue of black holes with nonlinear electromagnetic field, focussing mainly in the Born-Infeld case. The main features of these systems are described, for instance, geodesics, energy conditions, thermodynamics and isolated horizon aspects. Also are revised some black hole solutions of alternative nonlinear electrodynamics and its inconveniences.
DEFF Research Database (Denmark)
Vestergaard, Marianne
2004-01-01
The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.......The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized....
The effect of interferon-beta on black holes in patients with multiple sclerosis.
Bagnato, Francesca; Evangelou, Iordanis E; Gallo, Antonio; Gaindh, Deeya; Yao, Karen
2007-07-01
Multiple sclerosis (MS) is an immunological disorder of the CNS. Linked to an initial transient inflammation as the result of blood-brain barrier leakage, the disease progresses into a neurodegenerative phase. MRI is the most powerful paraclinical tool for diagnosing and monitoring MS. Although contrast enhancing lesions are the visible events of blood-brain barrier breakdown, accumulation of hypointense lesions, namely black holes, are recognised as irreversible axonal loss. IFN-beta is administered as a first-line drug in MS patients. However, whether the effect of IFN-beta extends beyond just prevention of blood-brain barrier leakage and further prevents the formation of black holes or promotes their recovery once formed, is not yet understood. PMID:17665995
Perturbed disks get shocked. Binary black hole merger effects on accretion disks
Megevand, Miguel; Frank, Juhan; Hirschmann, Eric W; Lehner, Luis; Liebling, Steven L; Motl, Patrick M; Neilsen, David
2009-01-01
The merger process of a binary black hole system can have a strong impact on a circumbinary disk. In the present work we study the effect of both central mass reduction (due to the energy loss through gravitational waves) and a possible black hole recoil (due to asymmetric emission of gravitational radiation). For the mass reduction case and recoil directed along the disk's angular momentum, oscillations are induced in the disk which then modulate the internal energy and bremsstrahlung luminosities. On the other hand, when the recoil direction has a component orthogonal to the disk's angular momentum, the disk's dynamics are strongly impacted, giving rise to relativistic shocks. The shock heating leaves its signature in our proxies for radiation, the total internal energy and bremsstrahlung luminosity. Interestingly, for cases where the kick velocity is below the smallest orbital velocity in the disk (a likely scenario in real AGN), we observe a common, characteristic pattern in the internal energy of the dis...
Quantum Tunneling in Black Holes
Majhi, Bibhas Ranjan
2011-01-01
This thesis is focussed towards the applications of the quantum tunneling mechanism to study black holes. Here we give a general frame work of the existing tunneling mechanism, both the radial null geodesic and Hamilton Jacobi methods. On the radial null geodesic method side, we study the modifications to the tunneling rate, Hawking temperature and the Bekenstein- Hawking area law by including the back reaction as well as non-commutative effects in the space-time. A reformulation of the Hamilton-Jacobi (HJ) method is first introduced. Based on this, a close connection between the quantum tunneling and the gravitational anomaly mechanisms to discuss Hawking effect, is put forwarded. An interesting advantage of this reformulated HJ method is that one can get directly the emission spectrum from the event horizon of the black hole, which was missing in the earlier literature. Also, the quantization of the entropy and area of a black hole is discussed in this method. Another part of the thesis is the introduction ...
Hod, Shahar
2016-01-01
It has recently been suggested (S.B. Giddings (2016) [2] ) that the Hawking black-hole radiation spectrum originates from an effective quantum “atmosphere' which extends well outside the black-hole horizon. In particular, comparing the Hawking radiation power of a (3+1) -dimensional Schwarzschild black hole of horizon radius rH with the familiar Stefan–Boltzmann radiation power of a (3+1) -dimensional flat space perfect blackbody emitter, Giddings concluded that the source of the Hawking semi...
Effects of Black Hole Spin on the Limit-Cycle Behaviour of Accretion Disks
Indian Academy of Sciences (India)
Li Xue; Ju-Fu Lu
2011-03-01
We present a spatially 1.5-dimensional, time-dependent numerical study of accretion disks around Kerr black holes. Our study focuses on the limit-cycle behavior of thermally unstable accretion disks. We find that maximal luminosity may be a more appropriate probe of black hole spin than the cycle duration and influence radius.
The Effect of Pair-Instability Mass Loss on Black Hole Mergers
Belczynski, K; Gladysz, W; Ruiter, A J; Woosley, S; Wiktorowicz, G; Chen, H -Y; Bulik, T; O'Shaughnesy, R; Holz, D E; Fryer, C L; Berti, E
2016-01-01
Mergers of two stellar origin black holes are a prime source of gravitational waves and are under intensive investigations. One crucial ingredient in their modeling has so far been neglected. Pair-instability pulsation supernovae with associated severe mass loss may suppress formation of massive black holes, decreasing black hole merger rates for the highest black hole masses. The mass loss associated with pair-instability pulsation supernovae limits the Population I/II stellar-origin black hole mass to 50 Msun, in tension with earlier predictions that the maximum black hole mass could be as high as 100 Msun. Suppression of double black hole merger rates by pair-instability pulsation supernovae is negligible for our evolutionary channel. Our standard evolutionary model with inclusion of pair-instability pulsation supernovae and with pair-instability supernovae is fully consistent with the LIGO detections of black hole mergers: GW150914, GW151226 and LVT151012. The LIGO observations seem to exclude high (>400 ...
Can Black Hole Relax Unitarily?
Solodukhin, S N
2004-01-01
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.
Quantum black hole without singularity
Kiefer, Claus
2015-01-01
We discuss the quantization of a spherical dust shell in a rigorous manner. Classically, the shell can collapse to form a black hole with a singularity. In the quantum theory, we construct a well-defined self-adjoint extension for the Hamilton operator. As a result, the evolution is unitary and the singularity is avoided. If we represent the shell initially by a narrow wave packet, it will first contract until it reaches the region where classically a black hole would form, but then re-expands to infinity. In a way, the state can be interpreted as a superposition of a black hole with a white hole.
Effects of a lambdaPhi4 interaction on black-hole evaporation in two dimensions
International Nuclear Information System (INIS)
This paper examines the effects of interactions on particle emission by black holes. The model used is the lambdaPhi4 interaction for a massless scalar field Phi in a two-dimensional model for a black-hole space-time and is compared with the calculation for a flat-space model with spatially varying lambda. Although the models suffer from infrared divergences, a number of features of the effect of the interaction on the particle spectrum are discernible. In the absence of any interactions the state of the field is that of a thermal flux of outgoing particles with temperature T = 1/8πM (the Hawking temperature). If the ingoing state is the vacuum state, the interaction destroys the thermal nature of the outgoing flux. However, if the ingoing flux is thermal with the same temperature as the black hole, detailed balance maintains the thermal character of the outgoing flux. One can regard the ingoing and outgoing fluxes as two separate thermal baths which are coupled by the interaction. If they are at different temperatures, the interaction will destroy the thermal nature of both
Effects of Spin on High-Energy Radiation from Accreting Black Holes
Riordan, Michael O'; McKinney, Jonathan C
2016-01-01
Observations of jets in X-ray binaries show a correlation between radio power and black hole spin. This correlation, if confirmed, points towards the idea that relativistic jets may be powered by the rotational energy of black holes. In order to examine this further, we perform general-relativistic radiative transport calculations on magnetically arrested accretion flows, which are known to produce powerful jets via the Blandford-Znajek (BZ) mechanism. We find that the X-ray and gamma-ray emission strongly depend on spin and inclination angle. Surprisingly, the high-energy power does not show the same dependence on spin as the BZ jet power, but instead can be understood as a redshift effect. In particular, photons observed perpendicular to the spin axis suffer little net redshift until originating from close to the horizon. Such observers see deeper into the hot, dense, highly-magnetized inner disk region. This effect is largest for rapidly rotating black holes due to a combination of frame dragging and decre...
Gravitational amplitudes in black hole evaporation: the effect of non-commutative geometry
International Nuclear Information System (INIS)
Recent work in the literature has studied the quantum-mechanical decay of a Schwarzschild-like black hole, formed by gravitational collapse, into almost-flat spacetime and weak radiation at a very late time. The relevant quantum amplitudes have been evaluated for bosonic and fermionic fields, showing that no information is lost in collapse to a black hole. On the other hand, recent developments in non-commutative geometry have shown that, in general relativity, the effects of non-commutativity can be taken into account by keeping the standard form of the Einstein tensor on the left-hand side of the field equations and introducing a modified energy-momentum tensor as a source on the right-hand side. The present paper, relying on the recently obtained non-commutativity effect on a static, spherically symmetric metric, considers from a new perspective the quantum amplitudes in black hole evaporation. The general relativity analysis of spin-2 amplitudes is shown to be modified by a multiplicative factor F depending on a constant non-commutativity parameter and on the upper limit R of the radial coordinate. Limiting forms of F are derived which are compatible with the adiabatic approximation here exploited. Approximate formulae for the particle emission rate are also obtained within this framework
On the Bardeen-Petterson Effect in black hole accretion discs
Nealon, Rebecca; Nixon, Chris
2015-01-01
We investigate the effect of black hole spin on warped or misaligned accretion discs - in particular i) whether or not the inner disc edge aligns with the black hole spin and ii) whether the disc can maintain a smooth transition between an aligned inner disc and a misaligned outer disc, known as the Bardeen-Petterson effect. We employ high resolution 3D smoothed particle hydrodynamics simulations of $\\alpha$-discs subject to Lense-Thirring precession, focussing on the bending wave regime where the disc viscosity is smaller than the aspect ratio $\\alpha \\lesssim H/R$. We first address the controversy in the literature regarding possible steady-state oscillations of the tilt close to the black hole. We successfully recover such oscillations in 3D at both small and moderate inclinations ($\\lesssim 15^{\\circ}$), provided both Lense-Thirring and Einstein precession are present, sufficient resolution is employed, and provided the disc is not so thick so as to simply accrete misaligned. Second, we find that discs in...
Gravitational amplitudes in black hole evaporation: the effect of non-commutative geometry
Energy Technology Data Exchange (ETDEWEB)
Grezia, Elisabetta Di [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di Monte S Angelo, Via Cintia, Edificio N' , 80126 Naples (Italy); Esposito, Giampiero [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di Monte S Angelo, Via Cintia, Edificio N' , 80126 Naples (Italy); Miele, Gennaro [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di Monte S Angelo, Via Cintia, Edificio N' , 80126 Naples (Italy)
2006-11-21
Recent work in the literature has studied the quantum-mechanical decay of a Schwarzschild-like black hole, formed by gravitational collapse, into almost-flat spacetime and weak radiation at a very late time. The relevant quantum amplitudes have been evaluated for bosonic and fermionic fields, showing that no information is lost in collapse to a black hole. On the other hand, recent developments in non-commutative geometry have shown that, in general relativity, the effects of non-commutativity can be taken into account by keeping the standard form of the Einstein tensor on the left-hand side of the field equations and introducing a modified energy-momentum tensor as a source on the right-hand side. The present paper, relying on the recently obtained non-commutativity effect on a static, spherically symmetric metric, considers from a new perspective the quantum amplitudes in black hole evaporation. The general relativity analysis of spin-2 amplitudes is shown to be modified by a multiplicative factor F depending on a constant non-commutativity parameter and on the upper limit R of the radial coordinate. Limiting forms of F are derived which are compatible with the adiabatic approximation here exploited. Approximate formulae for the particle emission rate are also obtained within this framework.
Supersymmetric black holes in string theory
Mohaupt, T.
2007-01-01
We review recent developments concerning supersymmetric black holes in string theory. After a general introduction to the laws of black hole mechanics and to black hole entropy in string theory, we discuss black hole solutions in N=2 supergravity, special geometry, the black hole attractor equations and the underlying variational principle. Special attention is payed to the crucial role of higher derivative corrections. Finally we discuss black hole partition functions and their relation to t...
Prisons of Light - Black Holes
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.
Black Holes and Galaxy Metamorphosis
Holley-Bockelmann, K
2001-01-01
Supermassive black holes can be seen as an agent of galaxy transformation. In particular, a supermassive black hole can cause a triaxial galaxy to evolve toward axisymmetry by inducing chaos in centrophilic orbit families. This is one way in which a single supermassive black hole can induce large-scale changes in the structure of its host galaxy -- changes on scales far larger than the Schwarzschild radius ($O(10^{-5}) \\rm{pc}$) and the radius of influence of the black hole ($O(1)-O(100) \\rm{pc}$). We will discuss the transformative power of supermassive black holes in light of recent high resolution N-body realizations of cuspy triaxial galaxies.
Quantum strings and black holes
Damour, Thibault Marie Alban Guillaume
2001-01-01
The transition between (non supersymmetric) quantum string states and Schwarzschild black holes is discussed. This transition occurs when the string coupling $g^2$ (which determines Newton's constant) increases beyond a certain critical value $g_c^2$. We review a calculation showing that self-gravity causes a typical string state of mass $M$ to shrink, as the string coupling $g^2$ increases, down to a compact string state whose mass, size, entropy and luminosity match (for the critical value $g_c^2 \\sim (M \\sqrt{\\alpha'})^{-1}$) those of a Schwarzschild black hole. This confirms the idea (proposed by several authors) that the entropy of black holes can be accounted for by counting string states. The level spacing of the quantum states of Schwarzschild black holes is expected to be exponentially smaller than their radiative width. This makes it very difficult to conceive (even Gedanken) experiments probing the discreteness of the quantum energy levels of black holes.
Effect of Vacuum Energy on Evolution of Primordial Black Holes in Einstein Gravity
Nayak, Bibekananda
2011-01-01
We study the evolution of primordail black holes by considering present universe is no more matter dominated rather vacuum energy dominated. We also consider the accretion of radiation, matter and vacuum energy during respective dominance period. In this scenario, we found that radiation accretion efficiency should be less than 0.366 and accretion rate is much larger than previous analysis by B. Nayak et al. \\cite{ns}. Thus here primordial black holes live longer than previous works \\cite{ns}. Again matter accretion slightly increases the mass and lifetime of primordial black holes. However, the vacuum energy accretion is slightly complicated one, where accretion is possible only upto a critical time. This critical time depends on the values of accretion efficiency and formation time. If a primordial black hole lives beyond critical time, then its lifespan increases due to vacuum energy accretion. But for presently evaporating primordial black holes, critical time comes much later than their evaporating time ...
Hawking, Stephen W; Strominger, Andrew
2016-01-01
It has recently been shown that BMS 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 paper 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 ho...
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.
Hair of astrophysical black holes
Lyutikov, Maxim
2012-01-01
The "no hair" theorem is not applicable to black holes formed from 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_B = e \\Phi_\\infty /(\\pi c \\hbar), where \\Phi_\\infty is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. 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...
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. PMID:27341223
Bini, Donato; Bittencourt, Eduardo; Geralico, Andrea; Jantzen, Robert T.
2015-04-01
A general framework is developed to investigate the properties of useful choices of stationary spacelike slicings of stationary spacetimes whose congruences of timelike orthogonal trajectories are interpreted as the world lines of an associated family of observers, the kinematical properties of which in turn may be used to geometrically characterize the original slicings. On the other hand, properties of the slicings themselves can directly characterize their utility motivated instead by other considerations like the initial value and evolution problems in the 3-plus-1 approach to general relativity. An attempt is made to categorize the various slicing conditions or "time gauges" used in the literature for the most familiar stationary spacetimes: black holes and their flat spacetime limit.
Bini, Donato; Geralico, Andrea; Jantzen, Robert T
2015-01-01
A general framework is developed to investigate the properties of useful choices of stationary spacelike slicings of stationary spacetimes whose congruences of timelike orthogonal trajectories are interpreted as the world lines of an associated family of observers, the kinematical properties of which in turn may be used to geometrically characterize the original slicings. On the other hand properties of the slicings themselves can directly characterize their utility motivated instead by other considerations like the initial value and evolution problems in the 3-plus-1 approach to general relativity. An attempt is made to categorize the various slicing conditions or "time gauges" used in the literature for the most familiar stationary spacetimes: black holes and their flat spacetime limit.
QCD Effects in the Decays of TeV Black Holes
Alig, C; Oda, K; Alig, Christian; Drees, Manuel; Oda, Kin-ya
2006-01-01
In models with ``large'' and/or warped extra dimensions, the higher-dimensional Planck scale may be as low as a TeV. In that case black holes with masses of a few TeV are expected to be produced copiously in multi-TeV collisions, in particular at the LHC. These black holes decay through Hawking radiation into typically O(20) Standard Model particles. Most of these particles would be strongly interacting. Naively this would lead to a final state containing 10 or so hadronic jets. However, it has been argued that the density of strongly interacting particles would be so large that they thermalize, forming a ``chromosphere'' rather than well-defined jets. In order to investigate this, we perform a QCD simulation which includes parton-parton scattering in addition to parton showering. We find the effects of parton scattering to remain small for all cases we studied, leading to the conclusion that the decays of black holes with masses within the reach of the LHC will not lead to the formation of chromospheres.
Problem of mathematical deduction of the existence of black holes
Directory of Open Access Journals (Sweden)
Yuan-Shun Chin
1990-01-01
Full Text Available The mathematical proof of existence of Black Hole is based on the assumption of mass being independent of speed. Considering the effect of special relativity of the dependence of mass with speed there is no Black hole.
Stavridis, Adamantios; Will, Clifford M.
2009-01-01
Observations of gravitational waves from massive binary black hole systems at cosmological distances can be used to search for a dependence of the speed of propagation of the waves on wavelength, and thereby to bound the mass of a hypothetical graviton. We study the effects of precessions of the spins of the black holes and of the orbital angular momentum on the process of parameter estimation using matched filtering of gravitational-wave signals vs. theoretical template waveforms. For the pr...
Adler, Stephen L
2016-01-01
A frame dependent effective action motivated by the postulates of three-space general coordinate invariance and Weyl scaling invariance exactly mimics a cosmological constant in Robertson-Walker spacetimes. However, in a static spherically symmetric Schwarzschild-like geometry it modifies the black hole horizon structure within microscopic distances of the nominal horizon, in such a way that $g_{00}$ never vanishes. This could have important implications for the black hole "information paradox".
Gonzalez-Morales, Alma X.; Profumo, Stefano; Queiroz, Farinaldo S.(Department of Physics, Santa Cruz Institute for Particle Physics, University of California, 95064, Santa Cruz, CA, USA)
2014-01-01
Recent discoveries of optical signatures of black holes in dwarf galaxies indicates that low-mass galaxies can indeed host intermediate massive black holes. This motivates the assessment of the resulting effect on the host dark matter density profile, and the consequences for the constraints on the plane of the dark matter annihilation cross section versus mass, stemming from the non-observation of gamma rays from local dwarf spheroidals with the Fermi Large Area Telescope. We compute the den...
Quantum and thermodynamic aspects of Black Holes
International Nuclear Information System (INIS)
The main results originating from the attempts of trying to incorporate quantum and thermodynamic properties and concepts to the gravitational system black hole, essentially the Hawking effect and the four laws of thermodynamics are reviewed. (Author)
Rotating black hole and quintessence
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag 54001, Durban (South Africa)
2016-04-15
We discuss spherically symmetric exact solutions of the Einstein equations for quintessential matter surrounding a black hole, which has an additional parameter (ω) due to the quintessential matter, apart from the mass (M). In turn, we employ the Newman-Janis complex transformation to this spherical quintessence black hole solution and present a rotating counterpart that is identified, for α = -e{sup 2} ≠ 0 and ω = 1/3, exactly as the Kerr-Newman black hole, and as the Kerr black hole when α = 0. Interestingly, for a given value of parameter ω, there exists a critical rotation parameter (a = a{sub E}), which corresponds to an extremal black hole with degenerate horizons, while for a < a{sub E}, it describes a nonextremal black hole with Cauchy and event horizons, and no black hole for a > a{sub E}. We find that the extremal value a{sub E} is also influenced by the parameter ω and so is the ergoregion. (orig.)
Phase transition in black holes
Roychowdhury, Dibakar
2014-01-01
The present thesis is devoted towards the study of various aspects of the phase transition phenomena occurring in black holes defined in an Anti-de-Sitter (AdS) space. Based on the fundamental principles of thermodynamics and considering a grand canonical framework we examine various aspects of the phase transition phenomena occurring in AdS black holes. We analytically check that this phase transition between the smaller and larger mass black holes obey Ehrenfest relations defined at the critical point and hence confirm a second order phase transition. This include both the rotating and charged black holes in Einstein gravity. Apart from studying these issues, based on a canonical framework, we also investigate the critical behavior in charged AdS black holes. The scaling laws for these black holes are found to be compatible with the static scaling hypothesis. Finally, based on the usual framework of AdS/CFT duality, we investigate the phase transition phenomena occurring in charged hairy black holes defined...
A nonsingular rotating black hole
International Nuclear Information System (INIS)
The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)
Acceleration of Black Hole Universe
Zhang, Tianxi
2012-05-01
An alternative cosmological model called black hole universe has been recently proposed by the author. According to this model, the universe originated from a hot star-like black hole, and gradually grew up through a supermassive black hole to the present state by accreting ambient materials and merging with other black holes. The entire space is structured with an infinite number of layers hierarchically. The innermost three layers are the universe that we live, the outside space called mother universe, and the inside star-like and supermassive black holes called child universes. The outermost layer has an infinite radius and limits to zero for both the mass density and absolute temperature. All layers or universes are governed by the same physics, the Einstein general theory of relativity with the Robertson-Walker metric of space-time, and tend to expand outward physically. The evolution of the space structure is iterative. When one universe expands out, a new similar universe grows up from its inside. In this study. we will analyze the acceleration of black hole universe that accretes its ambient matter in an increasing rate. We will also compare the result obtained from the black hole universe model with the measurement of type Ia supernova and the result from the big bang cosmology.
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.
A nonsingular rotating black hole
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Durban (South Africa)
2015-11-15
The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)
Black hole entropy in two dimensions
Myers, R C
1994-01-01
Black hole entropy is studied for an exactly solvable model of two-dimensional gravity\\cite{rst1}, using recently developed Noether charge techniques\\cite{wald1}. This latter approach is extended to accomodate the non-local form of the semiclassical effective action. In the two-dimensional model, the final black hole entropy can be expressed as a local quantity evaluated on the horizon. This entropy is shown to satisfy an increase theorem on either the global or apparent horizon of a two-dimensional black hole.
Black Hole Remnants and the Information Puzzle
Banks, T; Strominger, A
1993-01-01
Magnetically charged dilatonic black holes have a perturbatively infinite ground state degeneracy associated with an infinite volume throat region of the geometry. A simple argument based on causality is given that these states do not have a description as ordinary massive particles in a low-energy effective field theory. Pair production of magnetic black holes in a weak magnetic field is estimated in a weakly-coupled semiclassical expansion about an instanton and found to be finite, despite the infinite degeneracy of states. This suggests that these states may store the information apparently lost in black hole scattering processes.
Quantum chaos and the black hole horizon
CERN. Geneva
2016-01-01
Thanks to AdS/CFT, the analogy between black holes and thermal systems has become a practical tool, shedding light on thermalization, transport, and entanglement dynamics. Continuing in this vein, recent work has shown how chaos in the boundary CFT can be analyzed in terms of high energy scattering right on the horizon of the dual black hole. The analysis revolves around certain out-of-time-order correlation functions, which are simple diagnostics of the butterfly effect. We will review this work, along with a general bound on these functions that implies black holes are the most chaotic systems in quantum mechanics. (NB Room Change to Main Auditorium)
Holographic actions from black hole entropy
Caravelli, Francesco; Modesto, Leonardo
2010-01-01
Using the Wald's relation between the Noether charge of diffeomorphisms and the entropy for a generic spacetime possessing a bifurcation surface, we introduce a method to obtain a family of higher order derivatives effective actions from the entropy of black holes. Our point of view is to consider fundamental the black hole entropy and the action an emerged object. We then specialize to a particular class of effective theories: the f(R) theories. We apply the idea, using a simple mind ansatz,...
Black Hole Bound State Metamorphosis
Chowdhury, Abhishek; Saha, Arunabha; Sen, Ashoke
2012-01-01
N=4 supersymmetric string theories contain negative discriminant states whose numbers are known precisely from microscopic counting formulae. On the macroscopic side, these results can be reproduced by regarding these states as multi-centered black hole configurations provided we make certain identification of apparently distinct multi-centered black hole configurations according to a precise set of rules. In this paper we provide a physical explanation of such identifications, thereby establishing that multi-centered black hole configurations reproduce correctly the microscopic results for the number of negative discriminant states without any ad hoc assumption.
The Black Hole Information Problem
Polchinski, Joseph
2016-01-01
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.
Evaporation of primordial black holes
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 left 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 N approximations.
Thermodynamics of Lifshitz black holes
Devecioǧlu, Deniz Olgu; Sarıoǧlu, Özgür
2011-06-01
We apply the recently extended conserved Killing charge definition of Abbott-Deser-Tekin formalism to compute, for the first time, the energies of analytic Lifshitz black holes in higher dimensions. We then calculate the temperature and the entropy of this large family of solutions, and study and discuss the first law of black hole thermodynamics. Along the way we also identify the possible critical points of the relevant quadratic curvature gravity theories. Separately, we also apply the generalized Killing charge definition to compute the energy and the angular momentum of the warped AdS3 black hole solution of the three-dimensional new massive gravity theory.
Black Holes Have Simple Feeding Habits
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
Black hole evaporation in an expanding universe
International Nuclear Information System (INIS)
We calculate the quantum radiation power of black holes which are asymptotic to the Einstein-de Sitter universe at spatial and null infinities. We consider two limiting mass accretion scenarios, no accretion and significant accretion. We find that the radiation power strongly depends on not only the asymptotic condition but also the mass accretion scenario. For the no accretion case, we consider the Einstein-Straus solution, where a black hole of constant mass resides in the dust Friedmann universe. We find negative cosmological correction besides the expected redshift factor. This is given in terms of the cubic root of ratio in size of the black hole to the cosmological horizon, so that it is currently of order 10-5(M/106Mo-dot)1/3(t/14Gyr)-1/3 but could have been significant at the formation epoch of primordial black holes. Due to the cosmological effects, this black hole has not settled down to an equilibrium state. This cosmological correction may be interpreted in an analogy with the radiation from a moving mirror in a flat spacetime. For the significant accretion case, we consider the Sultana-Dyer solution, where a black hole tends to increase its mass in proportion to the cosmological scale factor. In this model, we find that the radiation power is apparently the same as the Hawking radiation from the Schwarzschild black hole of which mass is that of the growing mass at each moment. Hence, the energy loss rate decreases and tends to vanish as time proceeds. Consequently, the energy loss due to evaporation is insignificant compared to huge mass accretion onto the black hole. Based on this model, we propose a definition of quasi-equilibrium temperature for general conformal stationary black holes
Spin-multipole effects in binary black holes and the test-body limit
Vines, Justin; Steinhoff, Jan
2016-01-01
We discuss the Hamiltonian for the conservative dynamics of generic-orbit arbitrary-mass-ratio spinning binary black holes, at the leading post-Newtonian orders at each order in an expansion in spins, to all orders in the spins. The leading-order couplings can all be obtained from a map to the motion of a test black hole (a test body with the spin-induced multipoles of a Kerr black hole) in the Kerr spacetime, as is confirmed with direct post-Newtonian calculations for arbitrary mass ratios. ...
Spin-multipole effects in binary black holes and the test-body limit
Vines, Justin
2016-01-01
We discuss the Hamiltonian for the conservative dynamics of generic-orbit arbitrary-mass-ratio spinning binary black holes, at the leading post-Newtonian orders at each order in an expansion in spins, to all orders in the spins. The leading-order couplings can all be obtained from a map to the motion of a test black hole (a test body with the spin-induced multipoles of a Kerr black hole) in the Kerr spacetime, as is confirmed with direct post-Newtonian calculations for arbitrary mass ratios. Furthermore, all of the couplings can be "deduced" from those of a pole-dipole test body in Kerr.
Hod, Shahar
2016-01-01
It has recently been suggested [S. B. Giddings, Phys. Lett. B {\\bf 754}, 39 (2016)] that the Hawking black-hole radiation spectrum originates from an effective quantum "atmosphere" which extends well outside the black-hole horizon. In particular, comparing the Hawking radiation power of a $(3+1)$-dimensional Schwarzschild black hole of horizon radius $r_{\\text{H}}$ with the familiar Stefan-Boltzmann radiation power of a $(3+1)$-dimensional flat space perfect blackbody emitter, Giddings concluded that the source of the Hawking semi-classical black-hole radiation is a quantum region outside the Schwarzschild black-hole horizon whose effective radius $r_{\\text{A}}$ is characterized by the relation $\\Delta r\\equiv r_{\\text{A}}-r_{\\text{H}}\\sim r_{\\text{H}}$. It is of considerable physical interest to test the general validity of Giddings's intriguing conclusion. To this end, we study the Hawking radiation of $(D+1)$-dimensional Schwarzschild black holes. We find that the dimensionless radii $r_{\\text{A}}/r_{\\text...
Erratic Black Hole Regulates Itself
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
Particles and scalar waves in noncommutative charged black hole spacetime
Bhar, Piyali; Rahaman, Farook; Biswas, Ritabrata(Indian Institute of Engineering Sceince and Technology Shibpur (Formerly, Bengal Engineering and Science University Shibpur), 711 013, Howrah, West Bengal, India); Mondal, U. F.
2015-01-01
In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately. A comparative study of noncommutative charged black hole and usual Reissner-Nordstrom black hole has been done. The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.
Particles and Scalar Waves in Noncommutative Charged Black Hole Spacetime
Piyali, Bhar; Farook, Rahaman; Ritabrata, Biswas; U. F., Mondal
2015-07-01
In this paper we have discussed geodesics and the motion of test particle in the gravitational field of non-commutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately. A comparative study of noncommutative charged black hole and usual Reissner-Nordström black hole has been done. The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.
Charged dilatonic black holes in gravity's rainbow
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.
Black holes in a cubic Galileon universe
Babichev, E.; Charmousis, C.; Lehébel, A.; Moskalets, T.
2016-09-01
We find and study the properties of black hole solutions for a subclass of Horndeski theory including the cubic Galileon term. The theory under study has shift symmetry but not reflection symmetry for the scalar field. The Galileon is assumed to have linear time dependence characterized by a velocity parameter. We give analytic 3-dimensional solutions that are akin to the BTZ solutions but with a non-trivial scalar field that modifies the effective cosmological constant. We then study the 4-dimensional asymptotically flat and de Sitter solutions. The latter present three different branches according to their effective cosmological constant. For two of these branches, we find families of black hole solutions, parametrized by the velocity of the scalar field. These spherically symmetric solutions, obtained numerically, are different from GR solutions close to the black hole event horizon, while they have the same de-Sitter asymptotic behavior. The velocity parameter represents black hole primary hair.
Black holes in a cubic Galileon universe
Babichev, Eugeny; Lehébel, Antoine; Moskalets, Tetiana
2016-01-01
We find and study the properties of black hole solutions for a subclass of Horndeski theory including the cubic Galileon term. The theory under study has shift symmetry but not reflection symmetry for the scalar field. The Galileon is assumed to have linear time dependence characterized by a velocity parameter. We give analytic 3-dimensional solutions that are akin to the BTZ solutions but with a non-trivial scalar field that modifies the effective cosmological constant. We then study the 4-dimensional asymptotically flat and de Sitter solutions. The latter present three different branches according to their effective cosmological constant. For two of these branches, we find families of black hole solutions, parametrized by the velocity of the scalar field. These spherically symmetric solutions, obtained numerically, are different from GR solutions close to the black hole event horizon, while they have the same de-Sitter asymptotic behavior. The velocity parameter represents black hole primary hair.
(Anti-)Evaporation of Schwarzschild-de Sitter Black Holes
Bousso, R; Bousso, Raphael; Hawking, Stephen
1998-01-01
We study the quantum evolution of black holes immersed in a de Sitter background space. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. Our model includes the one-loop effective action in the s-wave and large N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, we find that nearly maximal quantum Schwarzschild-de Sitter black holes anti-evaporate. However, there is a different perturbative mode that leads to evaporation. We show that this mode will always be excited when a pair of cosmological holes nucleates.
(Anti-)evaporation of Schwarzschild-de Sitter black holes
Bousso, Raphael; Hawking, Stephen W.
1998-02-01
We study the quantum evolution of black holes immersed in a de Sitter background space. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. Our model includes the one-loop effective action in the s-wave and large N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, we find that nearly maximal quantum Schwarzschild-de Sitter black holes anti-evaporate. However, there is a different perturbative mode that leads to evaporation. We show that this mode will always be excited when a pair of cosmological holes nucleates.
On the quantization of the noncommutative geometry inspired black hole
Lee, Jong-Phil
2012-01-01
Black holes in noncommutative geometry background are considered to be quantized in accordance with the holographic principle. Incomplete gamma function involving the effective black hole mass is replaced by a discrete sum. The mass spectrum as well as the temperature of black holes is presented. The spectra are discrete ones but the shapes are very consistent with the known continuous results.
Vasudevan, R. V.; Fabian, A. C.; Reynolds, C. S.; Aird, J.; Dauser, T.; Gallo, L. C.
2016-05-01
The cosmic X-ray background (CXB) is the total emission from past accretion activity on to supermassive black holes in active galactic nuclei (AGN) and peaks in the hard X-ray band (30 keV). In this paper, we identify a significant selection effect operating on the CXB and flux-limited AGN surveys, and outline how they must depend heavily on the spin distribution of black holes. We show that, due to the higher radiative efficiency of rapidly spinning black holes, they will be over-represented in the X-ray background, and therefore could be a dominant contributor to the CXB. Using a simple bimodal spin distribution, we demonstrate that only 15 per cent maximally spinning AGN can produce 50 per cent of the CXB. We also illustrate that invoking a small population of maximally spinning black holes in CXB synthesis models can reproduce the CXB peak without requiring large numbers of Compton-thick AGN. The spin bias is even more pronounced for flux-limited surveys: 7 per cent of sources with maximally spinning black holes can produce half of the source counts. The detectability for maximum spin black holes can be further boosted in hard (>10 keV) X-rays by up to ˜60 per cent due to pronounced ionized reflection, reducing the percentage of maximally spinning black holes required to produce half of the CXB or survey number counts further. A host of observations are consistent with an over-representation of high-spin black holes. Future NuSTAR and ASTRO-H hard X-ray surveys will provide the best constraints on the role of spin within the AGN population.
Canonical Entropy and Phase Transition of Rotating Black Hole
Institute of Scientific and Technical Information of China (English)
ZHAO Ren; WU Yue-Qin; ZHANG Li-Chun
2008-01-01
Recently, the Hawking radiation of a black hole has been studied using the tunnel effect method. The radiation spectrum of a black hole is derived. By discussing the correction to spectrum of the rotating black hole, we obtain the canonical entropy. The derived canonical entropy is equal to the sum of Bekenstein-Hawking entropy and correction term. The correction term near the critical point is different from the one near others. This difference plays an important role in studying the phase transition of the black hole. The black hole thermal capacity diverges at the critical point. However, the canonical entropy is not a complex number at this point. Thus we think that the phase transition created by this critical point is the second order phase transition. The discussed black hole is a five-dimensional Kerr-AdS black hole. We provide a basis for discussing thermodynamic properties of a higher-dimensional rotating black hole.
Quantum tunneling radiation from self-dual black holes
Energy Technology Data Exchange (ETDEWEB)
Silva, C.A.S., E-mail: calex@fisica.ufc.br [Instituto Federal de Educação Ciência e Tecnologia da Paraíba (IFPB), Campus Campina Grande, Rua Tranquilino Coelho Lemos, 671, Jardim Dinamérica I (Brazil); Brito, F.A., E-mail: fabrito@df.ufcg.edu.br [Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraíba (Brazil)
2013-10-01
Black holes are considered as objects that can reveal quantum aspects of spacetime. Loop Quantum Gravity (LQG) is a theory that propose a way to model the quantum spacetime behavior revealed by a black hole. One recent prediction of this theory is the existence of sub-Planckian black holes, which have the interesting property of self-duality. This property removes the black hole singularity and replaces it with another asymptotically flat region. In this work, we obtain the thermodynamical properties of this kind of black holes, called self-dual black holes, using the Hamilton–Jacobi version of the tunneling formalism. Moreover, using the tools of the tunneling approach, we investigate the emission spectrum of self-dual black holes, and investigate if some information about the black hole initial state can be recovered during the evaporation process. Back-reaction effects are included.
Quantum tunneling radiation from self-dual black holes
Silva, C. A. S.; Brito, F. A.
2013-10-01
Black holes are considered as objects that can reveal quantum aspects of spacetime. Loop Quantum Gravity (LQG) is a theory that propose a way to model the quantum spacetime behavior revealed by a black hole. One recent prediction of this theory is the existence of sub-Planckian black holes, which have the interesting property of self-duality. This property removes the black hole singularity and replaces it with another asymptotically flat region. In this work, we obtain the thermodynamical properties of this kind of black holes, called self-dual black holes, using the Hamilton-Jacobi version of the tunneling formalism. Moreover, using the tools of the tunneling approach, we investigate the emission spectrum of self-dual black holes, and investigate if some information about the black hole initial state can be recovered during the evaporation process. Back-reaction effects are included.
Accretion, Primordial Black Holes and Standard Cosmology
Nayak, Bibekananda; Singh, Lambodar Prasad
2009-01-01
Primordial Black Holes evaporate due to Hawking radiation. We find that the evaporation time of primordial black holes increase when accretion of radiation is included.Thus depending on accretion efficiency more and more number of primordial black holes are existing today, which strengthens the idea that the primordial black holes are the proper candidate for dark matter.
Black Hole Complementary Principle and Noncommutative Membrane
International Nuclear Information System (INIS)
In the spirit of black hole complementary principle, we have found the noncommutative membrane of Scharzchild black holes. In this paper we extend our results to Kerr black hole and see the same story. Also we make a conjecture that spacetimes are noncommutative on the stretched membrane of the more general Kerr-Newman black hole.
Accretion, primordial black holes and standard cosmology
Indian Academy of Sciences (India)
B Nayak; P Singh
2011-01-01
Primordial black holes evaporate due to Hawking radiation. We find that the evaporation times of primordial black holes increase when accretion of radiation is included. Thus, depending on accretion efficiency, more primordial black holes are existing today, which strengthens the conjecture that the primordial black holes are the proper candidates for dark matter.
Towards a Theory of Quantum Black Hole
Berezin, V.
2001-01-01
We describe some specific quantum black hole model. It is pointed out that the origin of a black hole entropy is the very process of quantum gravitational collapse. The quantum black hole mass spectrum is extracted from the mass spectrum of the gravitating source. The classical analog of quantum black hole is constructed.
Formation of Supermassive Black Holes
Volonteri, Marta
2010-01-01
Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.
Black hole accretion disc impacts
Pihajoki, P.
2016-04-01
We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength λ = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.
Black hole accretion disc impacts
Pihajoki, Pauli
2015-01-01
We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.
Black hole interior mass formula
International Nuclear Information System (INIS)
We argue by explicit computations that, although the area product, horizon radii product, entropy product, and irreducible mass product of the event horizon and Cauchy horizon are universal, the surface gravity product, the surface temperature product and the Komar energy product of the said horizons do not seem to be universal for Kerr-Newman black hole spacetimes. We show the black hole mass formula on the Cauchy horizon following the seminal work by Smarr [Phys Rev Lett 30:71 (1973), Phys Rev D 7:289 (1973)] for the outer horizon. We also prescribe the four laws of black hole mechanics for the inner horizon. A new definition of the extremal limit of a black hole is discussed. (orig.)
Some Aspects of Intermediate mass black holes
Sivaram, C; Arun, Kenath
2007-01-01
There is a lot of current astrophysical evidence and interest in intermediate mass black holes, ranging from a few hundred to several thousand solar masses. The active galaxy M82 and the globular cluster in M31, for example, are known to host such objects. Here we discuss several aspects of intermediate mass black holes such as their expected luminosity, spectral nature of radiation, associated jets, etc. We also discuss possible scenarios for their formation including the effects of dynamica...
Systematic Errors in Black Hole Mass Measurements
McConnell, Nicholas J.
2014-01-01
Compilations of stellar- and gas-dynamical measurements of supermassive black holes are often assembled without quantifying systematic errors from various assumptions in the dynamical modeling processes. Using a simple Monte-Carlo approach, I will discuss the level to which different systematic effects could bias scaling relations between black holes and their host galaxies. Given that systematic errors will not be eradicated in the near future, how wrong can we afford to be?
Black Hole Entropy and Exclusion Statistics
Kim, Hyeong-Chan; Kim, Yoonbai(Department of Physics, BK21 Physics Research Division, Institute of Basic Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea); Oh, Phillial
1998-01-01
We compute the entropy of systems of quantum particles satisfying the fractional exclusion statistics in the space-time of 2+1 dimensional black hole by using the brick-wall method. We show that the entropy of each effective quantum field theory with a Planck scale ultraviolet cutoff obeys the area law, irrespective of the angular momentum of the black hole and the statistics interpolating between Bose-Einstein and Fermi-Dirac statistics.
Maxi-black holes - real navigation hazards
International Nuclear Information System (INIS)
Some of the physics that would be found outside black holes, if such objects really do exist in the Universe, is described. The subject is considered in relation to teaching and matters considered include the Schwarzsch radius, density problems, and the effect of the local acceleration of gravity due to black hole chasms. The impossibility of flying through the event horizon and coming out in another Universe, as postulated by some authors, is demonstrated. (U.K.)
Charged Dilatonic Black Holes in Gravity's Rainbow
Hendi, S H; Panah, B Eslam; Panahiyan, S
2015-01-01
In this paper, we analyze charged dilatonic black holes in gravity's rainbow. We obtain metric functions and different thermodynamic quantities for these charged black holes in dilatonic gravity's rainbow. We demonstrate that first law of thermodynamics is valid for these solutions. We also investigate thermal stability of these solutions using canonical ensemble. Finally, we analyze the effect that the variation of different parameters has on the stability of these solutions.
Van Herck, Walter
2009-01-01
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, arXiv:0810.4301. 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 hep-th/0702012, 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...
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.
Royzen, Ilya I
2009-01-01
Along with compacting baryon (neutron) spacing, two very important factors come into play at once: the lack of self-stabilization within a compact neutron star (NS) associated with possible black hole (BH) horizon appearance and the phase transition - color deconfinement and QCD-vacuum reconstruction - within the nuclear matter. That is why both phenomena should be taken into account side by side, as the gravitational collapse is considered. Since, under the above transition, the hadronic-phase vacuum (filled up with gluon and chiral $q\\bar q$-condensates) turns into the "empty" (perturbation) subhadronic-phase one and, thus, the corresponding (very high) pressure falls down rather abruptly, the formerly cold (degenerated) nuclear medium starts to implode into the new vacuum. If the mass of a star is sufficiently large, then this implosion produces an enormous heating, which stops only after quark-gluon plasma of a temperature about 100 MeV (or even higher) is formed to withstand the gravitational compression...
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
Overspinning a Kerr black hole: the effect of self-force
Colleoni, Marta
2015-01-01
We study the scenario in which a massive particle is thrown into a rapidly rotating Kerr black hole in an attempt to spin it up beyond its extremal limit, challenging weak cosmic censorship. We work in black-hole perturbation theory, and focus on non-spinning, uncharged particles sent in on equatorial orbits. We first identify the complete parameter-space region in which overspinning occurs when back-reaction effects from the particle's self-gravity are ignored. We find, in particular, that overspinning can be achieved only with particles sent in from infinity. Gravitational self-force effects may prevent overspinning by radiating away a sufficient amount of the particle's angular momentum ("dissipative effect"), and/or by increasing the effective centrifugal repulsion, so that particles with suitable parameters never get captured ("conservative effect"). We analyze the full effect of the self-force, thereby completing previous studies by Jacobson and Sotiriou (who neglected the self-force) and by Barausse, C...
The effect of lensing magnification on the apparent distribution of black hole mergers
Dai, Liang; Sigurdson, Kris
2016-01-01
The recent detection of gravitational waves indicates that stellar-mass black hole binaries are likely to be a key population of sources for forthcoming observations. With future upgrades, ground-based detectors could detect merging black hole binaries out to cosmological distances. Gravitational wave bursts from high redshifts ($z \\gtrsim 1$) can be strongly magnified by gravitational lensing due to intervening galaxies along the line of sight. In the absence of electromagnetic counterparts, the mergers' intrinsic mass scale and redshift are degenerate with the unknown magnification factor $\\mu$. Hence, strongly magnified low-mass mergers from high redshifts appear as higher-mass mergers from lower redshifts. We assess the impact of this degeneracy on the mass-redshift distribution of observable events for generic models of binary black hole formation from normal stellar evolution, Pop III star remnants, or a primordial black hole population. We find that strong magnification ($\\mu \\gtrsim 3$) generally crea...
Quantum Black Holes Effects on the Shape of Extensive Air Showers
Arsene, Nicusor; Denton, Peter B; Micu, Octavian
2013-01-01
We investigate the possibility to find a characteristic TeV scale quantum black holes decay signature in the data recorded by cosmic rays experiments. TeV black holes can be produced via the collisions of ultra high energetic protons (E > $10^18$ eV) with nucleons the from atmosphere. We focus on the case when the black holes decay into two particles moving in the forward direction in the Earth reference frame (back-to-back in the center of mass reference frame) and induce two overlapping showers. When reconstructing both the energy and the shape of the resultant air shower, there is a significant difference between showers induced only via standard model interactions and showers produced via the back-to-back decay of black holes as intermediate states.
Effect of the flow composition on outflow rates from accretion discs around black holes
Kumar, Rajiv; Chattopadhyay, Indranil; Chakrabarti, Sandip K
2013-01-01
We studied the outflow behaviour from accretion discs around black holes taking into account the vertical equilibrium accretion flow model. The outflow rate is found to depend crucially on flow composition. Our approach is to study the outflow behaviour as function of inflow around black holes with an equation of state which allows flow to be thermally relativistic close to black holes and non relativistic far away from black holes. We studied shock ejection model. A pure electron positron pair flow never undergoes shock transition while presence of some baryons (common in outflows and jets) makes it possible to have standing shock waves in the flow. It can be concluded that the presence of protons is necessary for the flow to show the outflow behaviour. The outflow rate is maximum when the flow contains the proton number density which is 27% of the electron number density. We conclude that a pure electron-positron jet is unlikely to form.
Vacuum metastability with black holes.
Burda, Philipp; Gregory, Ruth; Moss, Ian
2015-01-01
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 evapor...
Energy Extraction from Black Holes
Straumann, Norbert
2007-01-01
In this lecture I give an introduction to the rotational energy extraction of black holes by the electromagnetic Blandford-Znajek process and the generation of relativistic jets. After some basic material on the electrodynamics of black hole magnetospheres, we derive the most important results of Blandford and Znajek by making use of Kerr-Schild coordinates, which are regular on the horizon. In a final part we briefly describe results of recent numerical simulations of accretion flows on rota...
Myers, R C
2001-01-01
This is a short summary of my lectures given at the Fourth Mexican School on Gravitation and Mathematical Physics. These lectures gave a brief introduction to black holes in string theory, in which I primarily focussed on describing some of the recent calculations of black hole entropy using the statistical mechanics of D-brane states. The following overview will also provide the interested students with an introduction to the relevant literature.
Charged rotating noncommutative black holes
International Nuclear Information System (INIS)
In this paper we complete the program of the noncomutative geometry inspired black holes, providing the richest possible solution, endowed with mass, charge and angular momentum. After providing a prescription for employing the Newman-Janis algorithm in the case of nonvanishing stress tensors, we find regular axisymmetric charged black holes in the presence of a minimal length. We study also the new thermodynamics and we determine the corresponding higher-dimensional solutions. As a conclusion we make some consideration about possible applications.
Charged rotating noncommutative black holes
Modesto, Leonardo; Nicolini, Piero
2010-11-01
In this paper we complete the program of the noncomutative geometry inspired black holes, providing the richest possible solution, endowed with mass, charge and angular momentum. After providing a prescription for employing the Newman-Janis algorithm in the case of nonvanishing stress tensors, we find regular axisymmetric charged black holes in the presence of a minimal length. We study also the new thermodynamics and we determine the corresponding higher-dimensional solutions. As a conclusion we make some consideration about possible applications.
Charged rotating noncommutative black holes
Modesto, Leonardo
2010-01-01
In this paper we complete the program of the Noncomutative Geometry inspired black holes, providing the richest possible solution, endowed with mass, charge and angular momentum. After providing a prescription for employing the Newmann-Janis algorithm in case of nonvanishing stress tensors, we find regular axisymmetric charged black holes in the presence of a minimal length. We study also the new thermodynamics and we determine the corresponding higher-dimensional solutions. As a conclusion we make some consideration about possible applications.
Geometric inequalities for black holes
Dain, Sergio
2014-01-01
It is well known that the three parameters that characterize the Kerr black hole (mass, angular momentum and horizon area) satisfy several important inequalities. Remarkably, some of these inequalities remain valid also for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this article recent results in this subject are reviewed.
Black holes and cosmic censorship
International Nuclear Information System (INIS)
It is widely accepted that the complete gravitational collapse of a body always yields a black hole, and that naked singularities are never produced (the cosmic censorship hypothesis). The local (or strong) cosmic censorship hypothesis states that singularities which are even locally naked (e.g., to an observer inside a black hole) are never produced. This dissertation studies the validity of these two conjectures. The Kerr-Newman metrics describes the black holes only when M2 greater than or equal to Q2 + P2, where M is the mass of the black hole, a = J/M its specific angular momentum, Q its electric charge, and P its magnetic charge. In the first part of this dissertation, the possibility of converting an extreme Kerr-Newman black hole (M2 = a2 + Q2 + P2) into a naked singularity by the accretion of test particles is considered. The motion of test particles is studied with a large angular momentum to energy ratio, and also test particles with a large charge to energy ratio. The final state is always found to be a black hole if the angular momentum, electric charge, and magnetic charge of the black hole are all much greater than the corresponding angular momentum, electric charge, and magnetic charge of the test particle. In Part II of this dissertation possible black hole interior solutions are studied. The Cauchy horizons and locally naked timelike singularities of the charged (and/or rotating) solutions are contrasted with the spacelike all-encompassing singularity of the Schwarzschild solution. It is determined which portions of the analytic extension of the Reissner-Nordstroem solution are relevant to realistic gravitational collapse
Hayward, Sean A.; Mukohyama, Shinji; Ashworth, M. C.
1998-01-01
We consider two non-statistical definitions of entropy for dynamic (non-stationary) black holes in spherical symmetry. The first is analogous to the original Clausius definition of thermodynamic entropy: there is a first law containing an energy-supply term which equals surface gravity times a total differential. The second is Wald's Noether-charge method, adapted to dynamic black holes by using the Kodama flow. Both definitions give the same answer for Einstein gravity: one-quarter the area ...
Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew
2016-01-01
It has recently been shown that BMS 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 paper gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that com...
Probability for primordial black holes
Bousso, R.; Hawking, S. W.
1995-11-01
We consider two quantum cosmological models with a massive scalar field: an ordinary Friedmann universe and a universe containing primordial black holes. For both models we discuss the complex solutions to the Euclidean Einstein equations. Using the probability measure obtained from the Hartle-Hawking no-boundary proposal we find that the only unsuppressed black holes start at the Planck size but can grow with the horizon scale during the roll down of the scalar field to the minimum.
Information retrieval from black holes
Lochan, Kinjalk; Chakraborty, Sumanta; Padmanabhan, T.
2016-01-01
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 th...
New regular black hole solutions
International Nuclear Information System (INIS)
In the present work we consider general relativity coupled to Maxwell's electromagnetism and charged matter. Under the assumption of spherical symmetry, there is a particular class of solutions that correspond to regular charged black holes whose interior region is de Sitter, the exterior region is Reissner-Nordstroem and there is a charged thin-layer in-between the two. The main physical and geometrical properties of such charged regular black holes are analyzed.
Frampton, Paul H.
2009-01-01
While the energy of the universe has been established to be about 0.04 baryons, 0.24 dark matter and 0.72 dark energy, the cosmological entropy is almost entirely, about $(1 - 10^{-15})$, from black holes and only $10^{-15}$ from everything else. This identification of all dark matter as black holes is natural in statistical mechanics. Cosmological history of dark matter is discussed.
Are Black Holes Elementary Particles?
Ha, Yuan K.
2009-01-01
Quantum black holes are the smallest and heaviest conceivable elementary particles. They have a microscopic size but a macroscopic mass. Several fundamental types have been constructed with some remarkable properties. Quantum black holes in the neighborhood of the Galaxy could resolve the paradox of ultra-high energy cosmic rays detected in Earth's atmosphere. They may also play a role as dark matter in cosmology.
Destruction and recreation of black holes
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
Spinning boson stars and Kerr black holes with scalar hair: the effect of self-interactions
Herdeiro, Carlos A R; Rúnarsson, Helgi F
2016-01-01
Self-interacting boson stars have been shown to alleviate the astrophysically low maximal mass of their non-self-interacting counterparts. We report some physical features of spinning self-interacting boson stars, namely their compactness, the occurence of ergo-regions and the scalar field profiles, for a sample of values of the coupling parameter. The results agree with the general picture that these boson stars are comparatively less compact than the non-self-interacting ones. We also briefly discuss the effect of scalar self-interactions on the properties of Kerr black holes with scalar hair.
Wang, Peng; Ying, Shuxuan
2015-01-01
We compute the black hole horizon entanglement entropy for a massless scalar field in the brick wall model by incorporating the minimal length. Taking the minimal length effects on the occupation number $n(\\omega,l)$ and the Hawking temperature into consideration, we obtain the leading UV divergent term and the subleading logarithmic term in the entropy. The leading divergent term scales with the horizon area. The subleading logarithmic term is the same as that in the usual brick wall model without the minimal length.
Wang, Peng; Yang, Haitang; Ying, Shuxuan
2016-01-01
We compute the black hole horizon entanglement entropy for a massless scalar field in the brick wall model by incorporating the minimal length. Taking the minimal length effects on the occupation number n(ω, l) and the Hawking temperature into consideration, we obtain the leading ultraviolet (UV) divergent term and the subleading logarithmic term in the entropy. The leading divergent term scales with the horizon area. The subleading logarithmic term is the same as that in the usual brick wall model without the minimal length.
Effect of Vacuum Energy on Evolution of Primordial Black Holes in Einstein Gravity
Nayak, Bibekananda; Jamil, Mubasher
2011-01-01
We study the evolution of primordail black holes by considering present universe is no more matter dominated rather vacuum energy dominated. We also consider the accretion of radiation, matter and vacuum energy during respective dominance period. In this scenario, we found that radiation accretion efficiency should be less than 0.366 and accretion rate is much larger than previous analysis by B. Nayak et al. \\cite{ns}. Thus here primordial black holes live longer than previous works \\cite{ns}...
The effect of lensing magnification on the apparent distribution of black hole mergers
Dai, Liang; Venumadhav, Tejaswi; Sigurdson, Kris
2016-01-01
The recent detection of gravitational waves indicates that stellar-mass black hole binaries are likely to be a key population of sources for forthcoming observations. With future upgrades, ground-based detectors could detect merging black hole binaries out to cosmological distances. Gravitational wave bursts from high redshifts ($z \\gtrsim 1$) can be strongly magnified by gravitational lensing due to intervening galaxies along the line of sight. In the absence of electromagnetic counterparts,...
On Thermodynamical Relation Between Rotating Charged BTZ Black Holes and Effective String Theory
Institute of Scientific and Technical Information of China (English)
Alexis Larra(~n)aga
2008-01-01
In this paper we study the first law of thermodynamics for the (2+1)-dimensional rotating charged BTZ black hole considering a pair of thermodynamical systems constructed with the two horizons of this solution. We show that these two systems are similar to the right and left movers of string theory and that the temperature associated with the black hole is the harmonic mean of the temperatures associated with these two systems.
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. PMID:15697889
Shadow of rotating regular black holes
Abdujabbarov, Ahmadjon; Ahmedov, Bobomurat; Ghosh, Sushant G
2016-01-01
We study the shadows cast by the different types of rotating regular black holes viz. Ay\\'on-Beato-Garc\\'ia {(ABG)}, Hayward, and Bardeen. These black holes have in addition to the total mass ($M$) and rotation parameter ($a$), different parameters as electric charge ($Q$), deviation parameter ($g$), and magnetic charge ($g_{*}$), respectively. Interestingly, the size of the shadow is affected by these parameters in addition to the rotation parameter. We found that the radius of the shadow in each case decreases monotonically and the distortion parameter increases when the value of these parameters increase. A comparison with the standard Kerr case is also investigated. We have also studied the influence of the plasma environment around regular black holes to discuss its shadow. The presence of the plasma affects the apparent size of the regular black hole's shadow to be increased due to two effects (i) gravitational redshift of the photons and (ii) radial dependence of plasma density.
Key problems in black hole physics today
Joshi, Pankaj S
2011-01-01
We review here some of the major open issues and challenges in black hole physics today, and the current progress on the same. It is pointed out that to secure a concrete foundation for the basic theory as well as astrophysical applications for black hole physics, it is essential to gain a suitable insight into these questions. In particular, we discuss the recent results investigating the final fate of a massive star within the framework of the Einstein gravity, and the stability and genericity aspects of the gravitational collapse outcomes in terms of black holes and naked singularities. Recent developments such as spinning up a black hole by throwing matter into it, and physical effects near naked singularities are considered. It is pointed out that some of the new results obtained in recent years in the theory of gravitational collapse imply interesting possibilities and understanding for the theoretical advances in gravity as well as towards new astrophysical applications.
Shadow of rotating regular black holes
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 holes and asymptotically safe gravity
Falls, Kevin; Raghuraman, Aarti
2010-01-01
Quantum gravitational corrections to black holes are studied in four and higher dimensions using a renormalisation group improvement of the metric. The quantum effects are worked out in detail for asymptotically safe gravity, where the short distance physics is characterized by a non-trivial fixed point of the gravitational coupling. We find that a weakening of gravity implies a decrease of the event horizon, and the existence of a Planck-size black hole remnant with vanishing temperature and vanishing heat capacity. The absence of curvature singularities is generic and discussed together with the conformal structure and the Penrose diagram of asymptotically safe black holes. The production cross section of mini-black holes in energetic particle collisions, such as those at the Large Hadron Collider, is analysed within low-scale quantum gravity models. Quantum gravity corrections imply that cross sections display a threshold, are suppressed in the Planckian, and reproduce the semi-classical result in the deep...
Massive Black Holes: formation and evolution
Rees, Martin J.; Volonteri, Marta
2007-01-01
Supermassive black holes are nowadays believed to reside in most local galaxies. Observations have revealed us vast information on the population of local and distant black holes, but the detailed physical properties of these dark massive objects are still to be proven. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. We briefly review here the basic properties of the population of supermassive black holes,...
Regular black hole in three dimensions
Myung, Yun Soo; Yoon, Myungseok
2008-01-01
We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.
Regular black hole in three dimensions
International Nuclear Information System (INIS)
We find a new black hole in three-dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare the thermodynamics of this black hole with that of a non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy. (orig.)
Regular black hole in three dimensions
Energy Technology Data Exchange (ETDEWEB)
Myung, Yun Soo [Inje University, Institute of Basic Science and School of Computer Aided Science, Gimhae (Korea); Yoon, Myungseok [Sogang University, Center for Quantum Spacetime, Seoul (Korea)
2009-07-15
We find a new black hole in three-dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare the thermodynamics of this black hole with that of a non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy. (orig.)
Line Emission from an Accretion Disk around a Black hole Effects of Disk Structure
Pariev, V I; Pariev, Vladimir I.; Bromley, Benjamin C.
1998-01-01
The observed iron K-alpha fluorescence lines in Seyfert-1 galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the line emission. These lines serve as powerful probes for examining the structure of inner regions of accretion disks. Previous studies of line emission have considered geometrically thin disks only, where the gas moves along geodesics in the equatorial plane of a black hole. Here we extend this work to consider effects on line profiles from finite disk thickness, radial accretion flow and turbulence. We adopt the Novikov and Thorne (1973) solution, and find that within this framework, turbulent broadening is the dominant new effect. The most prominent change in the skewed, double-horned line profiles is a substantial reduction in the maximum flux at both red and blue peaks. The effect is most pronounced when the inclination angle is large, and when the accretion rate is high. Thus, the effects discussed here may be important for future detailed model...
New Directions in Black Hole Astrophysics
Reynolds, C. S.
2002-12-01
The astrophysics of accreting black holes has been a scientific focus of most major future X-ray missions. In this presentation, I will describe how our science goals and expectations have been effected by new data from Chandra and XMM-Newton as well as new theoretical work. I will argue on the basis of XMM-Newton data that black hole spin does not manifest itself through subtle effects but may have dramatic astrophysical consequences. If this is correct, the exotic astrophysics of black hole spin, including astrophysical realizations of the Penrose and Blandford-Znajek processes, will be a principal focus of Constellation-X, XEUS and MAXIM. On the other hand, data from the late stages of the RXTE/ASCA missions as well as XMM-Newton suggest that the simple technique of relativistic X-ray iron line reverberation mapping, which was originally touted as a good method for studying the inner accretion disk, may be hard to realize. Finally, I will discuss recent theoretical/simulation work on the appearance of a MHD turbulent accretion disk around a black hole. Such simulations may be a good framework to understand future timing observations of Galactic Black Hole Candidates and their quasi-periodic oscillations. They also suggest a quantitative way of measuring the space-time geometry around supermassive black holes in AGN.
Black holes as bubble nucleation sites
International Nuclear Information System (INIS)
We consider the effect of inhomogeneities on the rate of false vacuum decay. Modelling the inhomogeneity by a black hole, we construct explicit Euclidean instantons which describe the nucleation of a bubble of true vacuum centred on the inhomogeneity. We find that inhomogeneity significantly enhances the nucleation rate over that of the Coleman-de Luccia instanton — the black hole acts as a nucleation site for the bubble. The effect is larger than previously believed due to the contributions to the action from conical singularities. For a sufficiently low initial mass, the original black hole is replaced by flat space during this process, as viewed by a single causal patch observer. Increasing the initial mass, we find a critical value above which a black hole remnant survives the process. This resulting black hole can have a higher mass than the original black hole, but always has a lower entropy. We compare the process to bubble-to-bubble transitions, where there is a semi-classical Lorentzian description in the WKB approximation
Reissner-Nordstroem Black Hole Thermodynamics In Noncommutative Spaces
International Nuclear Information System (INIS)
This paper considers the effects of space noncommutativity on the thermodynamics of a Reissner-Nordstroem black hole. In the first step, we extend the ordinary formalism of Bekenstein-Hawking to the case of charged black holes in commutative space. In the second step we investigate the effect of space noncommutativity on the thermodynamics of charged black holes. Finally we compare thermodynamics of charged black holes in commutative space with thermodynamics of Schwarzschild black hole in noncommutative space. In this comparison we explore some conceptual relation between charge and space noncommutativity. (author)
Line emission from an accretion disk around black hole effects of the disk structure
Pariev, V I; Bromley, Benjamin C.; Pariev, Vladimir I.
1998-01-01
The observed iron K-alpha fluorescence lines in Seyfert galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the line emission. Previous studies of line emission have considered only geometrically thin disks, where the gas moves along geodesics in the equatorial plane of a black hole. Here we extend this work to include effects on line profiles from finite disk thickness, radial accretion flow and turbulence. We adopt the Novikov-Thorne solution, and find that within this framework, turbulent broadening is the most significant effect. The most prominent changes in the skewed, double-horned line profiles is a substantial reduction in the maximum flux at both red and blue peaks. We show that at the present level of signal-to-noise in X-ray spectra, proper treatment of the actual structure of the accretion disk can change estimates of the inclination angle of the disk. Thus these effects will be important for future detailed modeling of high quality observational d...
Chandra Data Reveal Rapidly Whirling Black Holes
2008-01-01
A new study using results from NASA's Chandra X-ray Observatory provides one of the best pieces of evidence yet that many supermassive black holes are spinning extremely rapidly. The whirling of these giant black holes drives powerful jets that pump huge amounts of energy into their environment and affects galaxy growth. A team of scientists compared leading theories of jets produced by rotating supermassive black holes with Chandra data. A sampling of nine giant galaxies that exhibit large disturbances in their gaseous atmospheres showed that the central black holes in these galaxies must be spinning at near their maximum rates. People Who Read This Also Read... NASA’s Swift Satellite Catches First Supernova in The Act of Exploding Black Holes Have Simple Feeding Habits Jet Power and Black Hole Assortment Revealed in New Chandra Image Erratic Black Hole Regulates Itself "We think these monster black holes are spinning close to the limit set by Einstein's theory of relativity, which means that they can drag material around them at close to the speed of light," said Rodrigo Nemmen, a visiting graduate student at Penn State University, and lead author of a paper on the new results presented at American Astronomical Society in Austin, Texas. The research reinforces other, less direct methods previously used which have indicated that some stellar and supermassive black holes are spinning rapidly. According to Einstein's theory, a rapidly spinning black hole makes space itself rotate. This effect, coupled with gas spiraling toward the black hole, can produce a rotating, tightly wound vertical tower of magnetic field that flings a large fraction of the inflowing gas away from the vicinity of the black hole in an energetic, high-speed jet. Computer simulations by other authors have suggested that black holes may acquire their rapid spins when galaxies merge, and through the accretion of gas from their surroundings. "Extremely fast spin might be very common for large
Black-Hole Polarization and Cosmic Censorship
Hod, S
1999-01-01
The destruction of the black-hole event horizon is ruled out by both cosmic censorship and the generalized second law of thermodynamics. We test the consistency of this prediction in a (more) `dangerous' version of the gedanken experiment suggested by Bekenstein and Rosenzweig. A $U(1)$-charged particle is lowered {\\it slowly} into a near extremal black hole which is not endowed with a $U(1)$ gauge field. The energy delivered to the black hole can be {\\it red-shifted} by letting the assimilation point approach the black-hole horizon. At first sight, therefore, the particle is not hindered from entering the black hole and removing its horizon. However, we show that this dangerous situation is excluded by a combination of {\\it two} factors not considered in former gedanken experiments: the effect of the spacetime curvature on the electrostatic {\\it self-interaction} of the charged system (the black-hole polarization), and the {\\it finite} size of the charged body.
Detection of black holes from optical phenomena
International Nuclear Information System (INIS)
The way by which the bending of light rays around black holes could give rise to optical phenomena, other than the lens effect, leading to the detection of them, is examined. One such phenomenon is the fact that we will see a ring of brightness around the black hole when we flash light on it. Another phenomenon is the appearance of a nebulosity around the black hole coming from the scattering of light from all discrete sources of the sky when it passes near the black hole. We examine the surface brightness of the phenomena seen and calculate the maximum distance of the black hole in order for the associated phenomena to appear on photographs. We find that primordial black holes of mass M ≅ 1016 Msolarmasses would be detectable by the first phenomenon if they existed within 5 Mpc distance from us, while they would be detectable by the second phenomenon if they existed within 200-300 Mpc distance from us. (author)
International Nuclear Information System (INIS)
We study dissipative test electromagnetic fields in a black-hole background. Quantities such as surface velocity, tangential electric field, normal magnetic induction, total surface current, and conduction surface current are introduced and are shown to satisfy Ohm's law with a surface resistivity of 4π approx. = 377 ohms. Associated with these currents there exists a ''Joule heating''. These currents can exist when the black hole is inserted in an external electric circuit, but they can exist even in the absence of external currents. In particular, we study the eddy currents induced by the rotation of a black hole in an oblique uniform magnetic field, and we show how the computation of the ohmic losses allows a very simple derivation of the torque exerted on the hole
Evaporation of a black hole off of a tense brane
International Nuclear Information System (INIS)
We calculate the greybody factors for scalar, vector and graviton fields in the background of an exact black hole localized on a tensional 3-brane in a world with two large extra dimensions. Finite brane tension modifies the standard results for the case with of a black hole on a brane with negligible tension. For a black hole of a fixed mass, the power carried away into the bulk diminishes as the tension increases, because the effective Planck constant, and therefore entropy of a fixed mass black hole, increase. In this limit, the semiclassical description of black hole decay becomes more reliable
Domination of black hole accretion in brane cosmology.
Majumdar, A S
2003-01-24
We consider the evolution of primordial black holes formed during the high energy phase of the braneworld scenario. We show that the effect of accretion from the surrounding radiation bath is dominant compared to evaporation for such black holes. This feature lasts till the onset of matter (or black hole) domination of the total energy density which could occur either in the high energy phase or later. We find that the black hole evaporation times could be significantly large even for black holes with small initial mass to survive until several cosmologically interesting eras. PMID:12570481
Horizons of Coalescing Black Holes on Eguchi-Hanson Space
Yoo, Chul-Moon; Kimura, Masashi; Matsuno, Ken; Tomizawa, Shinya
2007-01-01
Using the numerical method, we study dynamics of coalescing black holes on the Eguchi-Hanson base space. Effects of a difference in spacetime topology on the black hole dynamics is discussed. We analyze appearance and disappearance process of marginal surfaces. In our calculation, the area of a coverall black hole horizon at the creation time in the coalescing black holes solutions on Eguchi-Hanson space is larger than that in the five-dimensional Kastor-Traschen solutions. This fact suggests that the black hole production on the Eguchi-Hanson space is easier than that on the flat space.
Curiel, Erik
2014-01-01
In the early 1970s it is was realized that there is a striking formal analogy between the Laws of black-hole mechanics and the Laws of classical thermodynamics. Before the discovery of Hawking radiation, however, it was generally thought that the analogy was only formal, and did not reflect a deep connection between gravitational and thermodynamical phenomena. It is still commonly held that the surface gravity of a stationary black hole can be construed as a true physical temperature and its area as a true entropy only when quantum effects are taken into account; in the context of classical general relativity alone, one cannot cogently construe them so. Does the use of quantum field theory in curved spacetime offer the only hope for taking the analogy seriously? I think the answer is `no'. To attempt to justify that answer, I shall begin by arguing that the standard argument to the contrary is not physically well founded, and in any event begs the question. Looking at the various ways that the ideas of "tempe...
Quantum criticality and black holes.
Sachdev, Subir; Müller, Markus
2009-04-22
Many condensed matter experiments explore the finite temperature dynamics of systems near quantum critical points. Often, there are no well-defined quasiparticle excitations, and so quantum kinetic equations do not describe the transport properties completely. The theory shows that the transport coefficients are not proportional to a mean free scattering time (as is the case in the Boltzmann theory of quasiparticles), but are completely determined by the absolute temperature and by equilibrium thermodynamic observables. Recently, explicit solutions of this quantum critical dynamics have become possible via the anti-de Sitter/conformal field theory duality discovered in string theory. This shows that the quantum critical theory provides a holographic description of the quantum theory of black holes in a negatively curved anti-de Sitter space, and relates its transport coefficients to properties of the Hawking radiation from the black hole. We review how insights from this connection have led to new results for experimental systems: (i) the vicinity of the superfluid-insulator transition in the presence of an applied magnetic field, and its possible application to measurements of the Nernst effect in the cuprates, (ii) the magnetohydrodynamics of the plasma of Dirac electrons in graphene and the prediction of a hydrodynamic cyclotron resonance. PMID:21825396
Stavridis, A.; Will, C. M.
2010-05-01
Observations of gravitational waves from massive binary black hole systems at cosmological distances can be used to search for a dependence of the speed of propagation of the waves on wavelength, and thereby to bound the mass of a hypothetical graviton. We study the effects of precession of the spins of the black holes and of the orbital angular momentum on the process of parameter estimation based on the method of matched filtering of gravitational-wave signals vs. theoretical template waveforms. For the proposed space interferometer LISA, we show that precession, and the accompanying modulations of the gravitational waveforms, are effective in breaking degeneracies among the parameters being estimated, and effectively restore the achievable graviton-mass bounds to levels obtainable from binary inspirals without spin. For spinning, precessing binary black hole systems of equal masses 106 Modot at 3 Gpc, the lower bounds on the graviton Compton wavelength achievable are of the order of 5 × 1016 km.
International Nuclear Information System (INIS)
Observations of gravitational waves from massive binary black hole systems at cosmological distances can be used to search for a dependence of the speed of propagation of the waves on wavelength, and thereby to bound the mass of a hypothetical graviton. We study the effects of precession of the spins of the black holes and of the orbital angular momentum on the process of parameter estimation based on the method of matched filtering of gravitational-wave signals vs. theoretical template waveforms. For the proposed space interferometer LISA, we show that precession, and the accompanying modulations of the gravitational waveforms, are effective in breaking degeneracies among the parameters being estimated, and effectively restore the achievable graviton-mass bounds to levels obtainable from binary inspirals without spin. For spinning, precessing binary black hole systems of equal masses 106 Mo-dot at 3 Gpc, the lower bounds on the graviton Compton wavelength achievable are of the order of 5 x 1016 km.
International Nuclear Information System (INIS)
Observations of gravitational waves from massive binary black-hole systems at cosmological distances can be used to search for a dependence of the speed of propagation of the waves on wavelength, and thereby to bound the mass of a hypothetical graviton. We study the effects of precessions of the spins of the black holes and of the orbital angular momentum on the process of parameter estimation based on the method of matched filtering of gravitational-wave signals vs theoretical template waveforms. For the proposed Laser Interferometer Space Antenna, we show that precessions, and the accompanying modulations of the gravitational waveforms, are effective in breaking degeneracies among the parameters being estimated, and effectively restore the achievable graviton-mass bounds to levels obtainable from binary inspirals without spin. For spinning, precessing binary black-hole systems of equal masses 106M· at 3 Gpc, the lower bounds on the graviton Compton wavelength achievable are of the order of 5x1016 km.
Stavridis, Adamantios
2009-01-01
Observations of gravitational waves from massive binary black hole systems at cosmological distances can be used to search for a dependence of the speed of propagation of the waves on wavelength, and thereby to bound the mass of a hypothetical graviton. We study the effects of precessions of the spins of the black holes and of the orbital angular momentum on the process of parameter estimation using matched filtering of gravitational-wave signals vs. theoretical template waveforms. For the proposed space interferometer LISA, we show that precessions, and the accompanying modulations of the gravitational waveforms, are effective in breaking degeneracies among the parameters being estimated, and effectively restore the achievable graviton-mass bounds to levels obtainable from binary inspirals without spin. For spinning, precessing binary black hole systems of equal masses (10^6 solar masses) at 3 Gpc, the bounds on the graviton Compton wavelength achievable are of the order of 5 X 10^{16} km.
Stavridis, Adamantios; Will, Clifford M.
2009-08-01
Observations of gravitational waves from massive binary black-hole systems at cosmological distances can be used to search for a dependence of the speed of propagation of the waves on wavelength, and thereby to bound the mass of a hypothetical graviton. We study the effects of precessions of the spins of the black holes and of the orbital angular momentum on the process of parameter estimation based on the method of matched filtering of gravitational-wave signals vs theoretical template waveforms. For the proposed Laser Interferometer Space Antenna, we show that precessions, and the accompanying modulations of the gravitational waveforms, are effective in breaking degeneracies among the parameters being estimated, and effectively restore the achievable graviton-mass bounds to levels obtainable from binary inspirals without spin. For spinning, precessing binary black-hole systems of equal masses 106M⊙ at 3 Gpc, the lower bounds on the graviton Compton wavelength achievable are of the order of 5×1016km.
Introduction to black hole microscopy
Jacobson, T A
1995-01-01
The aim of these notes is both to review the standard understanding of the Hawking effect, and to discuss the modifications to this understanding that might be required by new physics at short distances. The fundamentals of the Unruh effect are reviewed, and then the Hawking effect is explained as a ``gravitational Unruh effect", with particular attention to the state-dependence of this picture. The order of magnitude of deviations from the thermal spectrum of Hawking radiation is estimated under various hypotheses on physics at short distances. The behavior of black hole radiation in a linear model with altered short distance physics---the Unruh model---is discussed in detail. [Based on lectures given at the First Mexican School on Gravitation and Mathematical Physics, Guanajuato, December 1994.
Resource Letter BH-2: Black Holes
Gallo, Elena
2008-01-01
This resource letter is designed to guide students, educators, and researchers through (some of) the literature on black holes. Both the physics and astrophysics of black holes are discussed. Breadth has been emphasized over depth, and review articles over primary sources. We include resources ranging from non-technical discussions appropriate for broad audiences to technical reviews of current research. Topics addressed include classification of stationary solutions, perturbations and stability of black holes, numerical simulations, collisions, the production of gravity waves, black hole thermodynamics and Hawking radiation, quantum treatments of black holes, black holes in both higher and lower dimensions, and connections to nuclear and condensed matter physics. On the astronomical end, we also cover the physics of gas accretion onto black holes, relativistic jets, gravitationally red-shifted emission lines, evidence for stellar-mass black holes in binary systems and super-massive black holes at the centers...
Black holes and branes in string theory
Skenderis, K
1999-01-01
This is a set of introductory lecture notes on black holes in string theory. After reviewing some aspects of string theory such as dualities, brane solutions, supersymmetric and non-extremal intersection rules, we analyze in detail extremal and non-extremal 5d black holes. We first present the D-brane counting for extremal black holes. Then we show that 4d and 5d non-extremal black holes can be mapped to the BTZ black hole (times a compact manifold) by means of dualities. The validity of these dualities is analyzed in detail. We present an analysis of the same system in the spirit of the adS/CFT correspondence. In the ``near-horizon'' limit (which is actually a near inner-horizon limit for non-extremal black holes) the black hole reduces again to the BTZ black hole. A state counting is presented in terms of the BTZ black hole.
The effect of different eLISA-like configurations on massive black hole parameter estimation
Porter, Edward K
2015-01-01
As the theme for the future L3 Cosmic Vision mission, ESA has recently chosen the `Gravitational Wave Universe'. Within this call, a mission concept called eLISA has been proposed. This observatory has a current initial configuration consisting of 4 laser links between the three satellites, which are separated by a distance of one million kilometers, constructing a single channel Michelson interferometer. However, the final configuration for the observatory will not be fixed until the end of this decade. With this in mind, we investigate the effect of different eLISA-like configurations on massive black hole detections. This work compares the results of a Bayesian inference study of 120 massive black hole binaries out to a redshift of $z\\sim13$ for a $10^6$m arm-length eLISA with four and six links, as well as a $2\\times10^6$m arm-length observatory with four links. We demonstrate that the original eLISA configuration should allow us to recover the luminosity distance of the source with an error of less than ...
EFFECTS OF CIRCUMNUCLEAR DISK GAS EVOLUTION ON THE SPIN OF CENTRAL BLACK HOLES
Energy Technology Data Exchange (ETDEWEB)
Maio, Umberto [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching b. Muenchen (Germany); Dotti, Massimo [Department of Physics of the University of Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Petkova, Margarita [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, D-85741 Garching b. Muenchen (Germany); Perego, Albino [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Volonteri, Marta [Institut d' Astrophysique de Paris, 98bis Boulevard Arago, F-75014 Paris (France)
2013-04-10
Mass and spin are the only two parameters needed to completely characterize black holes (BHs) in general relativity. However, the interaction between BHs and their environment is where complexity lies, as the relevant physical processes occur over a large range of scales. That is particularly relevant in the case of supermassive black holes (SMBHs), hosted in galaxy centers, and surrounded by swirling gas and various generations of stars. These compete with the SMBH for gas consumption and affect both dynamics and thermodynamics of the gas itself. How the behavior of such a fiery environment influences the angular momentum of the gas accreted onto SMBHs, and, hence, BH spins, is uncertain. We explore the interaction between SMBHs and their environment via first three-dimensional sub-parsec resolution simulations (ranging from {approx}0.1 pc to {approx}1 kpc scales) that study the evolution of the SMBH spin by including the effects of star formation, stellar feedback, radiative transfer, and metal pollution according to the proper stellar yields and lifetimes. This approach is crucial in investigating the impact of star formation processes and feedback effects on the angular momentum of the material that could accrete on the central hole. We find that star formation and feedback mechanisms can locally inject significant amounts of entropy in the surrounding medium, and impact the inflow inclination angles and Eddington fractions. As a consequence, the resulting trends show upper-intermediate equilibrium values for the spin parameter of a {approx_equal} 0.6-0.9, corresponding to radiative efficiencies {epsilon} {approx_equal} 9%-15%. These results suggest that star formation feedback taking place in the circumnuclear disk during the infall alone cannot induce very strong chaotic trends in the gas flow, quite independently from the different numerical parameters.
Black holes: a slanted overview
International Nuclear Information System (INIS)
The black hole saga spanning some seventy years may be broadly divided into four phases, namely, (a) the dark ages when little was known about black holes even though they had come into existence quite early through the Schwarzschild solution, (b) the age of enlightenment bringing in deep and prolific discoveries, (c) the age of fantasy that cast black holes in all sorts of extraordinary roles, and (d) the golden age of relativistic astrophysics - to some extent similar to Dirac's characterisation of the development of quantum theory - in which black holes have been extensively used to elucidate a number of astrophysical phenomena. It is impossible to give here even the briefest outline of the major developments in this vast area. We shall only attempt to present a few aspects of black hole physics which have been actively pursued in the recent past. Some details are given in the case of those topics that have not found their way into text books or review articles. (author)
Macroscopic black holes, microscopic black holes and noncommutative membrane
Energy Technology Data Exchange (ETDEWEB)
Li Miao [Institute of Theoretical Physics, Academia Sinica, PO Box 2735, Beijing 100080 (China)
2004-07-21
We study the stretched membrane of a black hole as consisting of a perfect fluid. We find that the pressure of this fluid is negative and the specific heat is also negative. A surprising result is that if we are to assume the fluid to be composed of some quanta, then the dispersion relation of the fundamental quantum is E = m{sup 2}/k, with m at the scale of the Planck mass. There are two possible interpretations of this dispersion relation. One is the noncommutative spacetime on the stretched membrane and the other is that the fundamental quanta are microscopic black holes.
Macroscopic black holes, microscopic black holes and noncommutative membrane
International Nuclear Information System (INIS)
We study the stretched membrane of a black hole as consisting of a perfect fluid. We find that the pressure of this fluid is negative and the specific heat is also negative. A surprising result is that if we are to assume the fluid to be composed of some quanta, then the dispersion relation of the fundamental quantum is E = m2/k, with m at the scale of the Planck mass. There are two possible interpretations of this dispersion relation. One is the noncommutative spacetime on the stretched membrane and the other is that the fundamental quanta are microscopic black holes
Cao, Xinwu
2010-01-01
A power-law time-dependent lightcurve for active galactic nuclei (AGNs) is expected by the self-regulated black hole growth scenario, in which the feedback of AGNs expels gas and shut down accretion. This is also supported by the observed power-law Eddington ratio distribution of AGNs. At high redshifts, the AGN life timescale is comparable with (or even shorter than) the age of the universe, which set a constraint on the minimal Eddington ratio for AGNs on the assumption of a power-law AGN lightcurve. The black hole mass function (BHMF) of AGN relics is calculated by integrating the continuity equation of massive black hole number density on the assumption of the growth of massive black holes being dominated by mass accretion with a power-law Eddington ratio distribution for AGNs. The derived BHMF of AGN relics at z=0 can fit the measured local mass function of the massive black holes in galaxies quite well, provided the radiative efficiency ~0.1 and a suitable power-law index for the Eddington ratio distrib...
What can we learn about black-hole formation from black-hole X-ray binaries?
Nelemans, G.
2004-01-01
I discuss the effect of the formation of a black hole on a (close) binary and show some of the current constraints that the observed properties of black hole X-ray binaries put on the formation of black holes. In particular I discuss the evidence for and against asymmetric kicks imparted on the black hole at formation and find contradicting answers, as there seems to be evidence for kick for individual systems and from the Galactic $z$-distribution of black hole X-ray binaries, but not from t...
Accretion radiation from nearby isolated black holes
International Nuclear Information System (INIS)
Recent work attempting to establish the presence of dark matter in the solar neighbourhood has led to renewed interest in the search for the nature of this matter. Previous authors attempt to exclude large (>=2 solar mass) objects by considering their tidal effect on wide binaries. Here independent constraints on such dark massive objects, if they are black holes, are provided by the requirement that their radiation due to accretion from the ISM should not make the nearest ones directly observable as optical objects. The expected infrared brightness is also predicted. It is shown that halo holes must be less massive than about 103 solar masses, and that the dark matter in the galactic disc cannot be made up of black holes of mass more than 10solar masses. Even if black holes do not make up the dark matter, they are expected to be present in the disc as remnants of massive stars. (author)
Time dependent black holes and scalar hair
International Nuclear Information System (INIS)
We show how to correctly account for scalar accretion onto black holes in scalar field models of dark energy by a consistent expansion in terms of a slow roll parameter. At leading order, we find an analytic solution for the scalar field within our Hubble volume, which is regular on both black hole and cosmological event horizons, and compute the back reaction of the scalar on the black hole, calculating the resulting expansion of the black hole. Our results are independent of the relative size of black hole and cosmological event horizons. We comment on the implications for more general black hole accretion, and the no hair theorems. (paper)
Implementing black hole as efficient power plant
Wei, Shao-Wen; Liu, Yu-Xiao
2016-01-01
Treating the black hole molecules as working substance and considering its phase structure, we study the black hole heat engine by a charged anti-de Sitter black hole. In the reduced temperature-entropy chart, it is found that the work, heat, and efficiency of the engine are independent of the black hole charge. Applying the Rankine cycle with or without a back pressure mechanism to the black hole heat engine, the efficiency is numerically solved. The result shows that the black hole engine w...
Possible suppression of Hawking radiation from microscopic black holes
Ahn, Doyeol
2010-01-01
Microscopic black holes with mass in the TeV range to be produced in the Large Hadron Collider (LHC) should undergo the prompt and quasi-thermal evaporation by emitting Hawking radiation. If this Hawking decay is not universal, some black holes can live long enough to penetrate into the Earth and grow dangerously. At present, the effects of black hole internal quantum state evolution on the evaporation are not well understood. This study shows that Hawking decay could be suppressed when the black hole internal matter state is in the coherent state. In this case, black holes created in the LHC may live long enough to grow catastrophically. The condition to avoid this catastrophic situation is also discussed. Our results demonstrate that the black hole evaporation is strongly dependent on the black hole internal quantum state and its evolution.
Thermodynamic properties of black holes in de Sitter space
Li, Huai-Fan; Ma, Meng-Sen; Ma, Ya-Qin
2016-01-01
We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole in the view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit,...
Improved black hole fireworks: Asymmetric black-hole-to-white-hole tunneling scenario
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.
Energy on black hole spacetimes
Corichi, Alejandro
2012-01-01
We consider the issue of defining energy for test particles on a background black hole spacetime. We revisit the different notions of energy as defined by different observers. The existence of a time-like isometry allows for the notion of a total conserved energy to be well defined, and subsequently the notion of a gravitational potential energy is also meaningful. We then consider the situation in which the test particle is adsorbed by the black hole, and analyze the energetics in detail. In particular, we show that the notion of horizon energy es defined by the isolated horizons formalism provides a satisfactory notion of energy compatible with the particle's conserved energy. As another example, we comment a recent proposal to define energy of the black hole as seen by an observer at rest. This account is intended to be pedagogical and is aimed at the level of and as a complement to the standard textbooks on the subject.
Scrambling with matrix black holes
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.
Liouvillian perturbations of black holes
Couch, W. E.; Holder, C. L.
2007-10-01
We apply the well-known Kovacic algorithm to find closed form, i.e., Liouvillian solutions, to the differential equations governing perturbations of black holes. Our analysis includes the full gravitational perturbations of Schwarzschild and Kerr, the full gravitational and electromagnetic perturbations of Reissner-Nordstrom, and specialized perturbations of the Kerr-Newman geometry. We also include the extreme geometries. We find all frequencies ω, in terms of black hole parameters and an integer n, which allow Liouvillian perturbations. We display many classes of black hole parameter values and their corresponding Liouvillian perturbations, including new closed-form perturbations of Kerr and Reissner-Nordstrom. We also prove that the only type 1 Liouvillian perturbations of Schwarzschild are the known algebraically special ones and that type 2 Liouvillian solutions do not exist for extreme geometries. In cases where we do not prove the existence or nonexistence of Liouvillian perturbations we obtain sequences of Diophantine equations on which decidability rests.
Massive Black Holes and Galaxies
CERN. Geneva
2016-01-01
Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.
Vacuum polarization near black holes
International Nuclear Information System (INIS)
This chapter discusses the properties of the renormalized mean value of the square of the conformal (massless or massive) scalar field in the space-time of a charged rotating black hole. The vacuum polarization effects for the massive scalar fields are examined. With regard to small masses, the vacuum polarization effects do not allow the gravitational field to be strong enough to form an apparent horizon. In the massless case the explicit expression for the renormalized mean value is obtained when the point x is on the event horizon. The expression for the renormalized mean value on the horizon is obtained by using the series representation for the static Green's function in the Kerr background
Black hole evaporation as a Cosmic Censor
Düztaş, Koray
2015-01-01
In a recent work we have shown that it is possible to overspin a nearly extremal Kerr black hole by using integer spin test fields at a frequency slightly above the superradiance limit. In this work we incorporate the quantum effect of evaporation into the problem. We consider a nearly extremal evaporating black hole interacting with challenging test fields. Evaporation refers to either Hawking radiation or the Zeldovich-Unruh effect, which agree in the limit the surface gravity (temperature) tending to zero. We note that evaporation acts as a cosmic censor since it carries away the angular momentum of the black hole, proportionally more than its mass. The relevant amount of angular momentum carried away depends on the initial mass of the black hole and the period of interaction with the test field. We evaluate the efficiency of evaporation to prevent overspinning of black holes of different masses, against the maximum effect due to challenging test fields. We make an order of magnitude estimate to show that ...
The Geometry of Black Hole Singularities
Directory of Open Access Journals (Sweden)
Ovidiu Cristinel Stoica
2014-01-01
Full Text Available Recent results show that important singularities in General Relativity can be naturally described in terms of finite and invariant canonical geometric objects. Consequently, one can write field equations which are equivalent to Einstein's at nonsingular points but, in addition remain well-defined and smooth at singularities. The black hole singularities appear to be less undesirable than it was thought, especially after we remove the part of the singularity due to the coordinate system. Black hole singularities are then compatible with global hyperbolicity and do not make the evolution equations break down, when these are expressed in terms of the appropriate variables. The charged black holes turn out to have smooth potential and electromagnetic fields in the new atlas. Classical charged particles can be modeled, in General Relativity, as charged black hole solutions. Since black hole singularities are accompanied by dimensional reduction, this should affect Feynman's path integrals. Therefore, it is expected that singularities induce dimensional reduction effects in Quantum Gravity. These dimensional reduction effects are very similar to those postulated in some approaches to make Quantum Gravity perturbatively renormalizable. This may provide a way to test indirectly the effects of singularities, otherwise inaccessible.
The Geometry of Black Hole Singularities
International Nuclear Information System (INIS)
Recent results show that important singularities in General Relativity can be naturally described in terms of finite and invariant canonical geometric objects. Consequently, one can write field equations which are equivalent to Einstein's at nonsingular points but, in addition remain well-defined and smooth at singularities. The black hole singularities appear to be less undesirable than it was thought, especially after we remove the part of the singularity due to the coordinate system. Black hole singularities are then compatible with global hyperbolicity and do not make the evolution equations break down, when these are expressed in terms of the appropriate variables. The charged black holes turn out to have smooth potential and electromagnetic fields in the new atlas. Classical charged particles can be modeled, in General Relativity, as charged black hole solutions. Since black hole singularities are accompanied by dimensional reduction, this should affect Feynman's path integrals. Therefore, it is expected that singularities induce dimensional reduction effects in Quantum Gravity. These dimensional reduction effects are very similar to those postulated in some approaches to make Quantum Gravity perturbatively renormalizable. This may provide a way to test indirectly the effects of singularities, otherwise inaccessible
Begelman, Mitchell C
2012-01-01
We propose that the growth of supermassive black holes is associated mainly with brief episodes of highly super-Eddington infall of gas ("hyperaccretion"). 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 per cent of the hole's mass is ejected as a result of the plunge in opacity at temperatures below a few thousand degrees K, 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 empiri...
Asymptotic black hole quasinormal frequencies
Motl, Lubos; Neitzke, Andrew
2003-01-01
We give a new derivation of the quasinormal frequencies of Schwarzschild black holes in d greater than or equal to 4 and Reissner-Nordstrom black holes in d = 4, in the limit of infinite damping. For Schwarzschild in d greater than or equal to 4 we find that the asymptotic real part is THawkinglog(3) for scalar perturbations and for some gravitational perturbations; this confirms a result previously obtained by other means in the case d = 4. For Reissner-Nordstrom in d = 4 w...
Geometric inequalities for black holes
Energy Technology Data Exchange (ETDEWEB)
Dain, Sergio [Universidad Nacional de Cordoba (Argentina)
2013-07-01
Full text: A geometric inequality in General Relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities, which are valid in the dynamical and strong field regime, play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this talk I will review recent results in this subject. (author)
Black Hole Statistics from Holography
Shepard, Peter G.
2005-01-01
We study the microstates of the ``small'' black hole in the $\\half$-BPS sector of AdS$_5\\times S^5$, the superstar of Myers and Tafjord, using the powerful holographic description provided by LLM. The system demonstrates the inherently statistical nature of black holes, with the geometry of Myer and Tafjord emerging only after averaging over an ensemble of geometries. The individual microstate geometries differ in the highly non-trivial topology of a quantum foam at their core, and the entrop...
Information Loss in Black Holes
Hawking, Stephen William
2005-01-01
The question of whether information is lost in black holes is investigated using Euclidean path integrals. The formation and evaporation of black holes is regarded as a scattering problem with all measurements being made at infinity. This seems to be well formulated only in asymptotically AdS spacetimes. The path integral over metrics with trivial topology is unitary and information preserving. On the other hand, the path integral over metrics with non-trivial topologies leads to correlation functions that decay to zero. Thus at late times only the unitary information preserving path integrals over trivial topologies will contribute. Elementary quantum gravity interactions do not lose information or quantum coherence.
Information loss in black holes
Hawking, S. W.
2005-10-01
The question of whether information is lost in black holes is investigated using Euclidean path integrals. The formation and evaporation of black holes is regarded as a scattering problem with all measurements being made at infinity. This seems to be well formulated only in asymptotically AdS spacetimes. The path integral over metrics with trivial topology is unitary and information preserving. On the other hand, the path integral over metrics with nontrivial topologies leads to correlation functions that decay to zero. Thus at late times only the unitary information preserving path integrals over trivial topologies will contribute. Elementary quantum gravity interactions do not lose information or quantum coherence.
Charge and mass effects on the evaporation of higher-dimensional rotating black holes
International Nuclear Information System (INIS)
To study the dynamics of discharge of a brane black hole in TeV gravity scenarios, we obtain the approximate electromagnetic field due to the charged black hole, by solving Maxwell's equations perturbatively on the brane. In addition, arguments are given for brane metric corrections due to backreaction. We couple brane scalar and brane fermion fields with non-zero mass and charge to the background, and study the Hawking radiation process using well known low energy approximations as well as a WKB approximation in the high energy limit. We argue that contrary to common claims, the initial evaporation is not dominated by fast Schwinger discharge.
The effect of the tortoise coordinate on the stable study of the Schwarzschild black hole
Gui-hua, T; Zhong, S; Gui-hua, Tian; Wang, Shi-kun; Zhong, Shuquan
2006-01-01
Carefully analyze influence of the tortoise coordinates r* and t on the stable study of the Schwarzschild black hole. Actually, one should be cautious in using the compact property of the perturbation field: it is true only with respect with the coordinate r and proper time or "good time", not the tortoise coordinates r* and t. Therefore, the mathematical proof used in reference [7] is incorrect because of it relying on the compact property of the perturbation fields. The Schwarzschild black hole might be unstable[1]-[5
International Nuclear Information System (INIS)
In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.
Effect of Spin on Thermodynamical Quantities around Reissner-Nordstrom Black Holes
Institute of Scientific and Technical Information of China (English)
LI Zhong-Heng
2005-01-01
@@ Using the quantization procedure involving in the Boulware vacuum state and Killing time t, we evaluate the entropy density, energy density, pressure and equation of state around the Reissner-Nordstrom black hole by the Wentzel-Kramers-Brillouin approximation on the Teukolsky-type master equation. We find that, near the event horizon, there exist subleading order terms with spin dependence beyond the expected Minkowskian hightemperature contribution. In particular, the terms are important and cannot be neglected for near-extremal black hole cases. At large r, the Boulware state approaches the Minkowski vacuum and the theory agrees with that performed in Minkowski spacetime.
Mo, Jie-Xiong; Li, Gu-Qiang; Xu, Xiao-Bao
2016-04-01
The effects of a power-law Maxwell field on the critical phenomena of higher dimensional dilaton black holes are probed in detail. We successfully derive the analytic solutions of the critical point and carry out some checks to ensure that these critical quantities are positive. It is shown that the constraint on the parameter α describing the strength of the coupling of the electromagnetic field and the scalar field turns out to be 0 affected by the power-law Maxwell field. Moreover, critical exponents are found to coincide with those of other anti-de Sitter black holes, showing the powerful influence of mean field theory.
No new quantum thermal effect of Dirac particles in a charged Vaidya-de Sitter black hole
International Nuclear Information System (INIS)
It is shown that Hawking radiation of Dirac particles does not exist for P1, Q2 components but for P2, Q1, components in a charged Vaidya-de Sitter black hole. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles. The result illustrated in this paper there is no new quantum effect in the thermal radiation of Dirac particles in any spherically symmetric black holes
Jusufi, Kimet
2016-01-01
In this paper we study the quantum tunneling of charged and magnetized particles (magnetic monopoles) from the global monopole black hole by incorporating the quantum gravity effects. Starting from the modified Maxwell's equations and Generalized Uncertainty Relation (GUP), we recover the GUP corrected temperate for the global monopole black hole by solving the modified Dirac equation via Hamilton-Jacobi method. Furthermore, we also include the quantum corrections beyond the semiclassical approximation, in particular, first we find the logarithmic corrections of GUP corrected entropy and finally we calculate the GUP corrected specific heat capacity.
Suppressed black hole production from minimal length
International Nuclear Information System (INIS)
Large extra dimensions lower the Planck scale to values soon accessible. Motivated by string theory, the models of large extra dimensions predict a vast number of new effects in the energy range of the lowered Planck scale, among them the production of TeV-mass black holes. But not only is the Planck scale the energy scale at which effects of modified gravity become important. String theory as well as non-commutative quantum mechanics suggest that the Planck length acts a minimal length in nature, providing a natural ultraviolet cutoff and a limit to the possible resolution of spacetime. The minimal length effects thus become important in the same energy range in which the black holes are expected to form. In this Letter we examine the influence of the minimal length on the expected production rate of the black holes
International Nuclear Information System (INIS)
Anderson and Lemos (1988) noticed that the direction in which viscous torque transports angular momentum changes, close to a black hole, from outwards to inwards. We find here that close to a black hole the centrifugal force attracts particles towards the hole. We argue that these are particular examples of a general reversal in sense of the inward and outward directions for all dynamical effects of rotation close to the hole. Using results from the recent paper by Abramowicz, Carter and Lasota (1988) we explain that the reversal is not connected with dragging of inertial frames or with the difference between the angular velocities of the hole and of the surrounding matter but rather, it is an effect of curvature. For a Schwarzschild black hole the reversal takes place at the circular photon orbit (r=3M-tilde) because the geodesic curvature, R-tilde=r(1-3M-tilde/r), of the circles r = const. changes its sign there. (author). 13 refs, 7 figs, 1 tab
Boundary Effects on the Thermodynamics of Quantum Fields Near a Black Hole
Akant, Levent
2015-01-01
We study the thermodynamics of a quantum field in a spherical shell around a static black hole. We impose Dirichlet boundary conditions on the field and analyze their effects on the free energy and the entropy. We consider both bosonic and fermionic fields in Schwarzschild, Reissner-Nordstrom (RN) and dilatonic backgrounds. We show that the horizon divergencies get contributions from the boundary which, at the Hawking temperature are comparable to the bulk contributions. Moreover it is shown that the leading divergence is the same for all three geometries. Thermodynamics of the quantum fields are studied through the high temperature expansion. We give a derivation of the high temperature expansion in the presence of a chemical potential using Mellin transform and heat kernel methods.
Regular Black Holes with Cosmological Constant
Institute of Scientific and Technical Information of China (English)
MO Wen-Juan; CAI Rong-Gen; SU Ru-Keng
2006-01-01
We present a class of regular black holes with cosmological constant Λ in nonlinear electrodynamics. Instead of usual singularity behind black hole horizon, all fields and curvature invariants are regular everywhere for the regular black holes. Through gauge invariant approach, the linearly dynamical stability of the regular black hole is studied. In odd-parity sector, we find that the Λ term does not appear in the master equations of perturbations, which shows that the regular black hole is stable under odd-parity perturbations. On the other hand, for the even-parity sector, the master equations are more complicated than the case without the cosmological constant. We obtain the sufficient conditions for stability of the regular black hole. We also investigate the thermodynamic properties of the regular black hole, and find that those thermodynamic quantities do not satisfy the differential form of first law of black hole thermodynamics. The reason for violating the first law is revealed.
Implementing black hole as efficient power plant
Wei, Shao-Wen
2016-01-01
Treating the black hole molecules as working substance and considering its phase structure, we study the black hole heat engine by a charged anti-de Sitter black hole. In the reduced temperature-entropy chart, it is found that the work, heat, and efficiency of the engine are independent of the black hole charge. Applying the Rankine cycle with or without a back pressure mechanism to the black hole heat engine, the efficiency is numerically solved. The result shows that the black hole engine working along the Rankine cycle with a back pressure mechanism has a higher efficiency. This provides a novel and efficient mechanism to produce the useful mechanical work with black hole, and such heat engine may act as a possible energy source for the high energy astrophysical phenomena near the black hole.
Holographic actions from black hole entropy
Caravelli, Francesco
2010-01-01
Using the Wald's relation between the Noether charge of diffeomorphisms and the entropy for a generic spacetime possessing a bifurcation surface, we introduce a method to obtain a family of higher order derivatives effective actions from the entropy of black holes. Our point of view is to consider fundamental the black hole entropy and the action an emerged object. We then specialize to a particular class of effective theories: the f(R) theories. We apply the idea, using a simple mind ansatz, to loop quantum gravity and to a general class of log-corrected entropy formulas.
Pair creation of black holes during inflation
Bousso, R; Bousso, Raphael; Hawking, Stephen W
1996-01-01
Black holes came into existence together with the universe through the quantum process of pair creation in the inflationary era. We present the instantons responsible for this process and calculate the pair creation rate from the no boundary proposal for the wave function of the universe. We find that this proposal leads to physically sensible results, which fit in with other descriptions of pair creation, while the tunnelling proposal makes unphysical predictions. We then describe how the pair created black holes evolve during inflation. In the classical solution, they grow with the horizon scale during the slow roll-down of the inflaton field; this is shown to correspond to the flux of field energy across the horizon according to the First Law of black hole mechanics. When quantum effects are taken into account, however, it is found that most black holes evaporate before the end of inflation. Finally, we consider the pair creation of magnetically charged black holes, which cannot evaporate. In standard Eins...
Pair creation of black holes during inflation
Bousso, Raphael; Hawking, Stephen W.
1996-11-01
Black holes came into existence together with the universe through the quantum process of pair creation in the inflationary era. We present the instantons responsible for this process and calculate the pair creation rate from the no boundary proposal for the wave function of the universe. We find that this proposal leads to physically sensible results, which fit in with other descriptions of pair creation, while the tunneling proposal makes unphysical predictions. We then describe how the pair-created black holes evolve during inflation. In the classical solution, they grow with the horizon scale during the slow roll down of the inflaton field; this is shown to correspond to the flux of field energy across the horizon according to the first law of black hole mechanics. When quantum effects are taken into account, however, it is found that most black holes evaporate before the end of inflation. Finally, we consider the pair creation of magnetically charged black holes, which cannot evaporate. In standard Einstein-Maxwell theory we find that their number in the presently observable universe is exponentially small. We speculate how this conclusion may change if dilatonic theories are applied.
Fermionic greybody factors in dilaton black holes
International Nuclear Information System (INIS)
In this paper the question of the emission of fermions in the process of dilaton black hole evolution and its characteristics for different dilaton coupling constants α are studied. The main quantity of interest, the greybody factors, are calculated both numerically and in analytical approximation. The dependence of the rates of evaporation and behaviour on the dilaton coupling constant is analysed. Having calculated the greybody factors, we are able to address the question of the final fate of the dilaton black hole. For that we also need to perform dynamical treatment of the solution by considering the backreaction, which will show a crucial effect on the final result. We find a transition line in the (Q/M,α) plane that separates the two regimes for the fate of the black hole, decay regime and extremal regime. In the decay regime the black hole completely evaporates, while in the extremal regime the black hole approaches the extremal limit by radiation and becomes stable. (paper)
Thermodynamics of horizons: de Sitter black holes
Kubiznak, David
2015-01-01
The thermodynamics of asymptotically de Sitter black holes is more complex than that of their asymptotically anti-de Sitter cousins. The reason is twofold: i) An observer in between the black hole and cosmological horizon finds herself in a two temperature non-equilibrium state. ii) The absence of a Killing vector that is timelike everywhere outside the black hole horizon prevents one from defining a good notion of the asymptotic mass. To overcome these difficulties various approaches exist in the literature, for example the effective temperature approach has recently become popular. In this paper we follow a more straightforward path towards the thermodynamics of de Sitter black holes, an approach that will allow us to study these black holes in a way that is analogous to the anti-de Sitter case. As per usual, we formulate several thermodynamic first laws, one for each horizon present in the spacetime, and study their thermodynamics as if they were independent thermodynamic systems characterized by their own...
Modified dispersion relations and black hole physics
Ling, Yi; Hu, Bo; Li, Xiang
2005-01-01
A modified formulation of energy-momentum relation is proposed in the context of doubly special relativity. We investigate its impact on black hole physics. It turns out that such modification will give corrections to both the temperature and the entropy of black holes. In particular this modified dispersion relation also changes the picture of Hawking radiation greatly when the size of black holes approaching the Planck scale. It can prevent black holes from total evaporation, as a result pr...
Black-hole formation from stellar collapse
International Nuclear Information System (INIS)
I review the end-state of massive stellar evolution, following the evolution of these massive stars from the onset of collapse through the formation of a compact remnant and the possible supernova or hypernova explosion. In particular, I concentrate on the formation of black holes from stellar collapse: the fraction of stars that form black holes, the black-hole mass distribution and the velocities these black-hole remnants may receive during their formation process
Black holes sourced by a massless scalar
Cadoni, Mariano
2015-01-01
We construct asymptotically flat black hole solutions of Einstein-scalar gravity sourced by a nontrivial scalar field with 1/r asymptotic behaviour. Near the singularity the black hole behaves as the Janis-Newmann-Winicour-Wyman solution. The hairy black hole solutions allow for a consistent thermodynamical description. At large mass they have the same thermodynamical behaviour of the Schwarzschild black hole, whereas for small masses they differ substantially from the latter.
Merging galaxies and black hole ejections
Valtonen, M. J.
1990-01-01
In mergers of galaxies their central black holes are accumulated together. Researchers show that few black hole systems arise which decay through black hole collisions and black hole ejections. The ejection statistics are calculated and compared with two observed systems where ejections have been previously suggested: double radio sources and high redshift quasars near low redshift galaxies. In both cases certain aspects of the associations are explained by the merger hypothesis.
Noncommutative geometry inspired Schwarzschild black hole
Nicolini, Piero; Smailagic, Anais; Spallucci, Euro
2005-01-01
We investigate the behavior of a noncommutative radiating Schwarzschild black hole. It is shown that coordinate noncommutativity cures usual problems encountered in the description of the terminal phase of black hole evaporation. More in detail, we find that: the evaporation end-point is a zero temperature extremal black hole even in the case of electrically neutral, non-rotating, objects; there exists a finite maximum temperature that the black hole can reach before cooling down to absolute ...
Supermassive Black Holes and Their Environments
Colberg, Joerg M.; Di Matteo, Tiziana
2008-01-01
We make use of the first high--resolution hydrodynamic simulations of structure formation which self-consistently follows the build up of supermassive black holes introduced in Di Matteo et al. (2007) to investigate the relation between black holes (BH), host halo and large--scale environment. There are well--defined relations between halo and black hole masses and between the activities of galactic nuclei and halo masses at low redshifts. A large fraction of black holes forms anti--hierarchi...
Black hole growth in hierarchical galaxy formation.
Malbon, R. K.; Baugh, C M; Frenk, C. S.; Lacey, C. G.
2007-01-01
We incorporate a model for black hole growth during galaxy mergers into the semi-analytical galaxy formation model based on Lambda-CDM proposed by Baugh et al. (2005). Our black hole model has one free parameter, which we set by matching the observed zeropoint of the local correlation between black hole mass and bulge luminosity. We present predictions for the evolution with redshift of the relationships between black hole mass and bulge properties. Our simulations reproduce the evolution of ...
Will black holes eventually engulf the universe?
Martin-Moruno, Prado; Madrid, Jose A. Jimenez; Gonzalez-Diaz, Pedro F.
2006-01-01
The Babichev-Dokuchaev-Eroshenko model for the accretion of dark energy onto black holes has been extended to deal with black holes with non-static metrics. The possibility that for an asymptotic observer a black hole with large mass will rapidly increase and eventually engulf the Universe at a finite time in the future has been studied by using reasonable values for astronomical parameters. It is concluded that such a phenomenon is forbidden for all black holes in quintessential cosmological...
Quantum Black Holes As Elementary Particles
Ha, Yuan K.
2008-01-01
Are black holes elementary particles? Are they fermions or bosons? We investigate the remarkable possibility that quantum black holes are the smallest and heaviest elementary particles. We are able to construct various fundamental quantum black holes: the spin-0, spin 1/2, spin-1, and the Planck-charge cases, using the results in general relativity. Quantum black holes in the neighborhood of the Galaxy could resolve the paradox posed by the Greisen-Zatsepin-Kuzmin limit on the energy of cosmi...
Volonteri, Marta
2012-01-01
I briefly outline recent theoretical developments on the formation of the first massive black holes (MBHs) that may grow into the population of MBHs powering quasars and inhabiting galactic centers today. I also touch upon possible observational tests that may give insights on what the properties of the first MBHs were.
Close encounters of black holes
Giulini, D
2003-01-01
This is an introduction into the problem of how to set up black hole initial-data for the matter-free field equations of General Relativity. The approach is semi-pedagogical and addresses a more general audience of astrophysicists and students with no specialized training in General Relativity beyond that of an introductory lecture.
Black Holes and Exotic Spinors
Directory of Open Access Journals (Sweden)
J. M. Hoff da Silva
2016-05-01
Full Text Available Exotic spin structures are non-trivial liftings, of the orthogonal bundle to the spin bundle, on orientable manifolds that admit spin structures according to the celebrated Geroch theorem. Exotic spin structures play a role of paramount importance in different areas of physics, from quantum field theory, in particular at Planck length scales, to gravity, and in cosmological scales. Here, we introduce an in-depth panorama in this field, providing black hole physics as the fount of spacetime exoticness. Black holes are then studied as the generators of a non-trivial topology that also can correspond to some inequivalent spin structure. Moreover, we investigate exotic spinor fields in this context and the way exotic spinor fields branch new physics. We also calculate the tunneling probability of exotic fermions across a Kerr-Sen black hole, showing that the exotic term does affect the tunneling probability, altering the black hole evaporation rate. Finally we show that it complies with the Hawking temperature universal law.
Information retrieval from black holes
Lochan, Kinjalk; Padmanabhan, T
2016-01-01
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. Semi-classically, 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 non-thermal. 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 ...
Extremal Higher Spin Black Holes
Bañados, Máximo; Faraggi, Alberto; Jottar, Juan I
2015-01-01
The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require nor implies the existence of supersymmetry, we exemplify its consequences in the context of sl(3|2) + sl(3|2) Chern-Simons theory. Remarkably, while as usual not all extremal solutions preserve supersymmetries, we find that the higher spin setup allows for non-extremal supersymmetric black hole solutio...
Gravitating Disks Around Black Holes
Czech Academy of Sciences Publication Activity Database
Karas, Vladimír; Šubr, Ladislav
Cambridge : Cambridge University Press, 2010 - (Peterson, B.), s. 332-332 ISBN 978-0-521-76502-2. - (IAU Symposium Proceedings Series. 267). [Symposium of the International Astronomical Union /267./. Rio de Janeiro (BR), 10.08.2009-14.08.2009] Institutional research plan: CEZ:AV0Z10030501 Keywords : accretion disks * gravitation * black hole physics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics