Quasinormal modes of test fields around regular black holes
Bobir Toshmatov; Ahmadjon Abdujabbarov; Zden?k Stuchlík; Bobomurat Ahmedov
2015-04-25
We study scalar, electromagnetic and gravitational test fields in the Hayward, Bardeen and Ay\\'on-Beato-Garc\\'ia regular black hole spacetimes and demonstrate that the test fields are stable in all these spacetimes. Using the sixth order WKB approximation of the linear "axial" perturbative scheme, we determine dependence of the quasinormal mode (QNM) frequencies on the characteristic parameters of the test fields and the spacetime charge parameters of the regular black holes. We give also the greybody factors, namely the transmission and reflection coefficients of scattered scalar, electromagnetic and gravitational waves. We show that damping of the QNMs in regular black hole spacetimes is suppressed in comparison to the case of Schwarzschild black holes, and increasing charge parameter of the regular black holes increases reflection and decreases transmission factor of incident waves for each of the test fields.
Strains and Jets in Black Hole Fields
D. Bini; F. de Felice; A. Geralico
2007-12-14
We study the behaviour of an initially spherical bunch of particles emitted along trajectories parallel to the symmetry axis of a Kerr black hole. We show that, under suitable conditions, curvature and inertial strains compete to generate jet-like structures.
Exact black hole solution with a minimally coupled scalar field
Cristian Martinez; Ricardo Troncoso; Jorge Zanelli
2004-06-13
An exact four-dimensional black hole solution of gravity with a minimally coupled self-interacting scalar field is reported. The event horizon is a surface of negative constant curvature enclosing the curvature singularity at the origin, and the scalar field is regular everywhere outside the origin. This solution is an asymptotically locally AdS spacetime. The strong energy condition is satisfied on and outside the event horizon. The thermodynamical analysis shows the existence of a critical temperature, below which a black hole in vacuum undergoes a spontaneous dressing up with a nontrivial scalar field in a process reminiscent of ferromagnetism.
On geodesic dynamics in deformed black-hole fields
Old?ich Semerák; Petra Suková
2015-09-28
"Almost all" seems to be known about isolated stationary black holes in asymptotically flat space-times and about the behaviour of {\\em test} matter and fields in their backgrounds. The black holes likely present in galactic nuclei and in some X-ray binaries are commonly being represented by the Kerr metric, but actually they are not isolated (they are detected only thanks to a strong interaction with the surroundings), they are not stationary (black-hole sources are rather strongly variable) and they also probably do not live in an asymptotically flat universe. Such "perturbations" may query the classical black-hole theorems (how robust are the latter against them?) and certainly affect particles and fields around, which can have observational consequences. In the present contribution we examine how the geodesic structure of the static and axially symmetric black-hole space-time responds to the presence of an additional matter in the form of a thin disc or ring. We use several different methods to show that geodesic motion may become chaotic, to reveal the strength and type of this irregularity and its dependence on parameters. The relevance of such an analysis for galactic nuclei is briefly commented on.
Quasi-black holes: general features and purely field configurations
K. A. Bronnikov; O. B. Zaslavskii
2015-04-27
Objects that are on the threshold of forming the horizon but never collapse are called quasi-black holes (QBHs). We discuss the properties of the general spherically symmetric QBH metric without addressing its material source, including its limiting cases as the corresponding small parameter tends to zero. We then show that QBHs can exist among self-gravitating configurations of electromagnetic and dilatonic scalar fields without matter. These general results are illustrated by explicit examples of exact solutions.
Instability of a four-dimensional de Sitter black hole with a conformally coupled scalar field
Tom J. T. Harper; Paul A. Thomas; Elizabeth Winstanley; Phil M. Young
2004-08-11
We study the stability of new neutral and electrically charged four-dimensional black hole solutions of Einstein's equations with a positive cosmological constant and conformally coupled scalar field. The neutral black holes are always unstable. The charged black holes are also shown analytically to be unstable for the vast majority of the parameter space of solutions, and we argue using numerical techniques that the configurations corresponding to the remainder of the parameter space are also unstable.
Back-Reaction of Classical Fields on Black Hole Area Law
Wung-Hong Huang
2015-08-13
We study the back-reaction of classical Maxwell field and massive scalar field on the BTZ black hole entropy. The exact values of the modification which correct the black hole area law are found. We discuss the similar properties between the scalar and Maxwell field which is investigated in both of Coulomb gauge and Lorentz gauge. The dependences of mass and mode number on the black hole entropy are illustrated. We also study the back-reaction by D branes, which is described by DBI action, and explicitly check that the classical solution which gives the black hole entropy precisely corrects the black hole area law. Our results extend the calculations of the generalized gravitational entropy proposed in recent by Lewkowycz and Maldacena [1].
Back-Reaction of Classical Fields on Black Hole Area Law
Huang, Wung-Hong
2015-01-01
We study the back-reaction of classical Maxwell field and massive scalar field on the BTZ black hole entropy. The exact values of the modification which correct the black hole area law are found. We discuss the similar properties between the scalar and Maxwell field which is investigated in both of Coulomb gauge and Lorentz gauge. The dependences of mass and mode number on the black hole entropy are illustrated. We also study the back-reaction by D branes, which is described by DBI action, and explicitly check that the classical solution which gives the black hole entropy precisely corrects the black hole area law. Our results extend the calculations of the generalized gravitational entropy proposed in recent by Lewkowycz and Maldacena [1].
Back-Reaction of Classical Fields on Black Hole Area Law
Wung-Hong Huang
2015-08-17
We study the back-reaction of classical Maxwell field and massive scalar field on the BTZ black hole entropy. The exact values of the modification which correct the black hole area law are found. We discuss the similar properties between the scalar and Maxwell field which is investigated in both of Coulomb gauge and Lorentz gauge. The dependences of mass and mode number on the black hole entropy are illustrated. We also study the back-reaction by D branes, which are described by DBI action, and explicitly check that the classical solution which gives the black hole entropy precisely corrects the black hole area law. Our results extend the calculations of the generalized gravitational entropy proposed in recent by Lewkowycz and Maldacena [1].
Quantum Effects for the Dirac Field in Reissner-Nordstrom-AdS Black Hole Background
F. Belgiorno; S. L. Cacciatori
2007-10-10
The behavior of a charged massive Dirac field on a Reissner-Nordstrom-AdS black hole background is investigated. The essential self-adjointness of the Dirac Hamiltonian is studied. Then, an analysis of the discharge problem is carried out in analogy with the standard Reissner-Nordstrom black hole case.
Schwarzschild black hole levitating in the hyperextreme Kerr field
V. S. Manko; E. Ruiz
2015-11-05
The equilibrium configurations between a Schwarzschild black hole and a hyperextreme Kerr object are shown to be described by a three-parameter subfamily of the extended double-Kerr solution. For this subfamily, its Ernst potential and corresponding metric functions, we provide a physical representation which employs as arbitrary parameters the individual Komar masses and relative coordinate distance between the sources. The calculation of horizon's local angular velocity induced in the Schwarzschild black hole by the Kerr constituent yields a simple expression inversely proportional to the square of the distance parameter.
Dynamics of Scalar Fields in the Background of Rotating Black Holes
W. Krivan; P. Laguna; P. Papadopoulos
1996-06-04
A numerical study of the evolution of a massless scalar field in the background of rotating black holes is presented. First, solutions to the wave equation are obtained for slowly rotating black holes. In this approximation, the background geometry is treated as a perturbed Schwarzschild spacetime with the angular momentum per unit mass playing the role of a perturbative parameter. To first order in the angular momentum of the black hole, the scalar wave equation yields two coupled one-dimensional evolution equations for a function representing the scalar field in the Schwarzschild background and a second field that accounts for the rotation. Solutions to the wave equation are also obtained for rapidly rotating black holes. In this case, the wave equation does not admit complete separation of variables and yields a two-dimensional evolution equation. The study shows that, for rotating black holes, the late time dynamics of a massless scalar field exhibit the same power-law behavior as in the case of a Schwarzschild background independently of the angular momentum of the black hole.
Stability of black holes in Einstein-charged scalar field theory in a cavity
Dolan, Sam R; Winstanley, Elizabeth
2015-01-01
Can a black hole that suffers a superradiant instability evolve towards a 'hairy' configuration which is stable? We address this question in the context of Einstein-charged scalar field theory. First, we describe a family of static black hole solutions which possess charged scalar-field hair confined within a mirror-like boundary. Next, we derive a set of equations which govern the linear, spherically symmetric perturbations of these hairy solutions. We present numerical evidence which suggests that, unlike the vacuum solutions, the (single-node) hairy solutions are stable under linear perturbations. Thus, it is plausible that stable hairy black holes represent the end-point of the superradiant instability of electrically-charged Reissner-Nordstrom black holes in a cavity; we outline ways to explore this hypothesis.
Back-reaction of a conformal field on a three-dimensional black hole
Cristian Martinez; Jorge Zanelli
1996-10-22
The first order corrections to the geometry of the (2+1)-dimensional black hole due to back-reaction of a massless conformal scalar field are computed. The renormalized stress energy tensor used as the source of Einstein equations is computed with the Green function for the black-hole background with transparent boundary conditions. This tensor has the same functional form as the one found in the nonperturbative case which can be exactly solved. Thus, a static, circularly symmetric and asymptotically anti-de Sitter black hole solution of the semiclassical equations is found. The corrections to the thermodynamic quantities are also computed.
Fermion Fields in BTZ Black Hole Space-Time and Entanglement Entropy
Dharm Veer Singh; Sanjay Siwach
2015-08-07
We study the entanglement entropy of fermion fields in BTZ black hole space-time and calculate pre- factor of the leading and sub-leading terms and logarithmic divergence term of the entropy using the discretized model. The leading term is the standard Bekenstein-Hawking area law and sub-leading term corresponds to first quantum corrections in black hole entropy. We also investigate the corrections to entanglement entropy for massive fermion fields in BTZ space-time. The mass term does not affect the area law.
Bruegger, C.; Kaempfer, F.; Wiese, U.-J.; Hofmann, C. P.; Pepe, M.
2007-01-01
Using the low-energy effective field theory for magnons and holes--the condensed matter analog of baryon chiral perturbation theory for pions and nucleons in QCD--we study different phases of doped antiferromagnets. We systematically investigate configurations of the staggered magnetization that provide a constant background field for doped holes. The most general configuration of this type is either constant itself or represents a spiral in the staggered magnetization. Depending on the values of the low-energy parameters, a homogeneous phase, a spiral phase, or an inhomogeneous phase is energetically favored. The reduction of the staggered magnetization upon doping is also investigated.
Thermodynamics of higher dimensional topological dilaton black holes with power-law Maxwell field
M. Kord Zangeneh; A. Sheykhi; M. H. Dehghani
2015-05-02
In this paper, we extend the study on the nonlinear power-law Maxwell field to dilaton gravity. We introduce the $(n+1)$-dimensional action in which gravity is coupled to a dilaton and power-law nonlinear Maxwell field, and obtain the field equations by varying the action. We construct a new class of higher dimensional topological black hole solutions of Einstein-dilaton theory coupled to a power-law nonlinear Maxwell field and investigate the effects of the nonlinearity of the Maxwell source as well as the dilaton field on the properties of the spacetime. Interestingly enough, we find that the solutions exist provided one assumes three Liouville-type potentials for the dilaton field, and in case of the Maxwell field one of the Liouville potential vanishes. After studying the physical properties of the solutions, we compute the mass, charge, electric potential and temperature of the topological dilaton black holes. We also study thermodynamics and thermal stability of the solutions and disclose the effects of the dilaton field and the power-law Maxwell field on the thermodynamics of these black holes. Finally, we comment on the dynamical stability of the obtained solutions in four-dimensions.
Resonant excitation of black holes by massive bosonic fields and giant ringings
Yves Decanini; Antoine Folacci; Mohamed Ould El Hadj
2014-03-20
We consider the massive scalar field, the Proca field and the Fierz-Pauli field in the Schwarzschild spacetime and we focus more particularly on their long-lived quasinormal modes. We show numerically that the associated excitation factors have a strong resonant behavior and we confirm this result analytically from semiclassical considerations based on the properties of the unstable circular geodesics on which a massive particle can orbit the black hole. The conspiracy of (i) the long-lived behavior of the quasinormal modes and (ii) the resonant behavior of their excitation factors induces intrinsic giant ringings, i.e., ringings of a huge amplitude. Such ringings, which are moreover slowly decaying, are directly constructed from the retarded Green function. If we describe the source of the black hole perturbation by an initial value problem with Gaussian initial data, i.e., if we consider the excitation of the black hole from an extrinsic point of view, we can show that these extraordinary ringings are still present. This suggests that physically realistic sources of perturbations should generate giant and slowly decaying ringings and that their existence could be used to constrain ultralight bosonic field theory interacting with black holes.
Hawking radiation for a scalar field conformally coupled to an AdS black hole
P. Valtancoli
2015-02-05
The decomposition in normal modes of a scalar field conformally coupled to an AdS black hole leads to a Heun equation with simple coefficients thanks to conformal invariance. By applying the Damour-Ruffini method we can relate the critical exponent of the radial part at the horizon surface to the Hawking radiation of scalar particles.
Magnetic and Electric Fields around the Black Hole in Cyg X-1
Yu. N. Gnedin; N. V. Borisov; T. M. Natsvlishvili; M. Yu. Piotrovich; N. A. Silant'ev
2003-04-09
Analysis of polarimetric observations of X-ray binary Cyg X-1/HDE 226868 including the data obtained by BTA-6m allows to estimate the magnetic field magnitude near the inner radius of the accretion disk. The magnetic field magnitude occurred to be $\\sim 10^{8}$ G. For power law of radial dependence of magnetic field into an accretion disk we estimates the value of an index of power law. For the Cyg X-1/HDE 226868 system the value of this index appears non less then two. If one accepts as a characteristic scale of a magnetic field generation region the dyadosphere radius, one can estimate the charge magnitude of a black hole. For Cyg X-1 this magnitude appears to be $\\sim 0.01M\\sqrt{G}$, where M is a black hole mass.
de Sitter black hole with a conformally coupled scalar field in four dimensions
Cristian Martinez; Ricardo Troncoso; Jorge Zanelli
2002-12-19
A four-dimensional black hole solution of the Einstein equations with a positive cosmological constant, coupled to a conformal scalar field, is given. There is a curvature singularity at the origin, and scalar field diverges inside the event horizon. The electrically charged solution, which has a fixed charge-to-mass ratio is also found. The quartic self-interacting coupling becomes bounded in terms of Newton's and the cosmological constants.
Thermodynamics of the Three-dimensional Black Hole with a Coulomb-like Field
Alexis Larranaga; Luz Angela Garcia
2008-11-21
In this paper, we study the thermodynamical properties of the (2+1)dimensional black hole with a Coulomb-like electric field and the differential form of the first law of thermodynamics is derived considering a virtual displacement of its event horizon. This approach shows that it is possible to give a thermodynamical interpretation to the field equations near the horizon. The Lambda=0 solution is studied and its interesting thermodynamical properties are commented.
Quasi-stationary solutions of self-gravitating scalar fields around black holes
Nicolas Sanchis-Gual; Juan Carlos Degollado; Pedro J. Montero; José A. Font
2014-12-29
Recent perturbative studies have shown the existence of long-lived, quasi-stationary configurations of scalar fields around black holes. In particular, such configurations have been found to survive for cosmological timescales, which is a requirement for viable dark matter halo models in galaxies based on such type of structures. In this paper we perform a series of numerical relativity simulations of dynamical non-rotating black holes surrounded by self-gravitating scalar fields. We solve numerically the coupled system of equations formed by the Einstein and the Klein-Gordon equations under the assumption of spherical symmetry using spherical coordinates. Our results confirm the existence of oscillating, long-lived, self-gravitating scalar fields configurations around non-rotating black holes in highly dynamical spacetimes with a rich scalar field environment. Our numerical simulations are long-term stable and allow for the extraction of the resonant frequencies to make a direct comparison with results obtained in the linearized regime. A byproduct of our simulations is the existence of a degeneracy in plausible long-lived solutions of Einstein equations that would induce the same motion of test particles, either with or without the existence of quasi-bound states.
Bruegger, C.; Kaempfer, F.; Moser, M.; Wiese, U.-J.; Pepe, M.
2006-12-01
Identifying the correct low-energy effective theory for magnons and holes in an antiferromagnet has remained an open problem for a long time. In analogy to the effective theory for pions and nucleons in QCD, based on a symmetry analysis of Hubbard and t-J-type models, we construct a systematic low-energy effective field theory for magnons and holes located inside pockets centered at lattice momenta ({+-}({pi}/2a),{+-}({pi}/2a)). The effective theory is based on a nonlinear realization of the spontaneously broken spin symmetry and makes model-independent universal predictions for the entire class of lightly doped antiferromagnetic precursors of high-temperature superconductors. The predictions of the effective theory are exact, order by order in a systematic low-energy expansion. We derive the one-magnon exchange potentials between two holes in an otherwise undoped system. Remarkably, in some cases the corresponding two-hole Schroedinger equations can even be solved analytically. The resulting bound states have d-wave characteristics. The ground state wave function of two holes residing in different hole pockets has a d{sub x{sup 2}-y{sup 2}}-like symmetry, while for two holes in the same pocket the symmetry resembles d{sub xy}.
String loops in the field of braneworld spherically symmetric black holes and naked singularities
Stuchlík, Z.; Kološ, M. E-mail: martin.kolos@fpf.slu.cz
2012-10-01
We study motion of current-carrying string loops in the field of braneworld spherically symmetric black holes and naked singularities. The spacetime is described by the Reissner-Nordström geometry with tidal charge b reflecting the non-local tidal effects coming from the external dimension; both positive and negative values of the spacetime parameter b are considered. We restrict attention to the axisymmetric motion of string loops when the motion can be fully governed by an appropriately defined effective potential related to the energy and angular momentum of the string loops. In dependence on these two constants of the motion, the string loops can be captured, trapped, or can escape to infinity. In close vicinity of stable equilibrium points at the centre of trapped states the motion is regular. We describe how it is transformed to chaotic motion with growing energy of the string loop. In the field of naked singularities the trapped states located off the equatorial plane of the system exist and trajectories unable to cross the equatorial plane occur, contrary to the trajectories in the field of black holes where crossing the equatorial plane is always admitted. We concentrate our attention to the so called transmutation effect when the string loops are accelerated in the deep gravitational field near the black hole or naked singularity by transforming the oscillatory energy to the energy of the transitional motion. We demonstrate that the influence of the tidal charge can be substantial especially in the naked singularity spacetimes with b > 1 where the acceleration to ultrarelativistic velocities with Lorentz factor ? ? 100 can be reached, being more than one order higher in comparison with those obtained in the black hole spacetimes.
Evolution of massive fields around a black hole in Horava gravity
Nijo Varghese; V C Kuriakose
2011-05-23
We study the evolution of massive scalar field in the spacetime geometry of Kehagias-Sfetsos(KS) black hole in deformed Horava-Lifshitz(HL) gravity by numerical analysis. We find that the signature of HL theory is encoded in the quasinormal mode(QNM) phase of the evolution of field. The QNM phase in the evolution process lasts for a longer time in HL theory. QNMs involved in the evolution of massive field are calculated and find that they have a higher oscillation frequency and a lower damping rate than the Schwarzschild spacetime case. We also study the relaxation of field in the intermediate and asymptotic range and verified that behaviors of field in these phases are independent of the HL parameter and is identical to the Schwarzschild case.
Ramon Becar; P. A. Gonzalez; Joel Saavedra; Yerko Vasquez
2014-12-19
We study massive charged fermionic perturbations in the background of a charged two-dimensional dilatonic black hole, and we solve the Dirac equation analytically. Then, we compute the reflection and transmission coefficients and the absorption cross section for massive charged fermionic fields, and we show that the absorption cross section vanishes at the low and high frequency limits. However, there is a range of frequencies where the absorption cross section is not null. Furthermore, we study the effect of the mass and electric charge of the fermionic field over the absorption cross section.
String-theoretic breakdown of effective field theory near black hole horizons
Dodelson, Matthew
2015-01-01
We investigate the validity of the equivalence principle near horizons in string theory, analyzing the breakdown of effective field theory caused by longitudinal string spreading effects. An experiment is set up where a detector is thrown into a black hole a long time after an early infalling string. Light cone gauge calculations, taken at face value, indicate a detectable level of root-mean-square longitudinal spreading of the initial string as measured by the late infaller. This results from the large relative boost between the string and detector in the near horizon region, which develops automatically despite their modest initial energies outside the black hole and the weak curvature in the geometry. We subject this scenario to basic consistency checks, using these to obtain a relatively conservative criterion for its detectability. In a companion paper, we exhibit longitudinal nonlocality in well-defined gauge-invariant S-matrix calculations, obtaining results consistent with the predicted spreading albe...
O. B. Zaslavskii
2015-09-06
We consider the behavior of the innermost stable circular orbit (ISCO) in the magnetic field near "dirty" (surrounded by matter) axially-symmetric black holes. The cases of near-extremal, extremal and nonextremal black holes are analyzed. For nonrotating black holes, in the strong magnetic field ISCO approaches the horizon (when backreaction of the field on geometry is neglected). Rotation destroys this phenomenon. The angular momentum and radius of ISCO look model-independent in the main approximation. We also study the collisions between two particles that results in the ultra-high energy $E_{c.m.}$ in the centre of mass frame. Two scenarios are considered - when one particle moves on the near-horizon ISCO or when collision occurs on the horizon, one particle having the energy and angular momentum typical of ISCO. If the magnetic field is strong enough and a black hole is slow rotating, $E_{c.m.}$ can become arbitrarily large. Kinematics of high-energy collision is discussed. As an example, we consider the magnetized Schwarzschild black hole for an arbitrary strength of the field (the Ernst solution). It is shown that backreaction of the magnetic field on the geometry can bound the growth of $E_{c.m.}$.
Galactic Halos and Black Holes in Non-Canonical Scalar Field Theories
Ratindranath Akhoury; Christopher S. Gauthier
2008-06-03
We consider static spherically symmetric solutions of a general scalar field theory with non-standard kinetic energy coupled to gravity with a view to explain dark matter halos as a coherent state of the scalar field. Consistent solutions are found with a smooth scalar profile which can describe observed rotation curves. Some of the solutions have negative scalar energy density near the origin though the total energy is positive definite. The solutions with positive energy density everywhere have a steeper rotation curve near the origin than those that don't. We also reconsider the no scalar hair theorems for black holes with emphasis on asymptotic boundary conditions and super-luminal propagation. Some modifications and extensions of previous analyses are discussed.
Galactic Halos and Black Holes in Non-Canonical Scalar Field Theories
Akhoury, Ratindranath
2008-01-01
We consider static spherically symmetric solutions of a general scalar field theory with non-standard kinetic energy coupled to gravity with a view to explain dark matter halos as a coherent state of the scalar field. Consistent solutions are found with a smooth scalar profile which can describe observed rotation curves. Some of the solutions have negative scalar energy density near the origin though the total energy is positive definite. The solutions with positive energy density everywhere have a steeper rotation curve near the origin than those that don't. We also reconsider the no scalar hair theorems for black holes with emphasis on asymptotic boundary conditions and super-luminal propagation. Some modifications and extensions of previous analyses are discussed.
Martin Kološ; Zden?k Stuchlík; Arman Tursunov
2015-06-22
In order to test the role of large-scale magnetic fields in quasiperiodic oscillation phenomena observed in microquasars, we study oscillatory motion of charged particles in vicinity of a Schwarzschild black hole immersed into an external asymptotically uniform magnetic field. We determine the fundamental frequencies of small harmonic oscillations of charged test particles around stable circular orbits in the equatorial plane of a magnetized black hole, and discuss the radial profiles of frequencies of the radial and latitudinal harmonic oscillations in dependence on the mass of the black hole and the strength of the magnetic field. We demonstrate that assuming relevance of resonant phenomena of the radial and latitudinal oscillations of charged particles at their frequency ratio $3:2$, the oscillatory frequencies of charged particles can be well related to the frequencies of the twin high-frequency quasi-periodic oscillations observed in the microquasars GRS 1915+105, XTE 1550-564 and GRO 1655-40.
Kološ, Martin; Tursunov, Arman
2015-01-01
In order to test the role of large-scale magnetic fields in quasiperiodic oscillation phenomena observed in microquasars, we study oscillatory motion of charged particles in vicinity of a Schwarzschild black hole immersed into an external asymptotically uniform magnetic field. We determine the fundamental frequencies of small harmonic oscillations of charged test particles around stable circular orbits in the equatorial plane of a magnetized black hole, and discuss the radial profiles of frequencies of the radial and latitudinal harmonic oscillations in dependence on the mass of the black hole and the strength of the magnetic field. We demonstrate that assuming relevance of resonant phenomena of the radial and latitudinal oscillations of charged particles at their frequency ratio $3:2$, the oscillatory frequencies of charged particles can be well related to the frequencies of the twin high-frequency quasi-periodic oscillations observed in the microquasars GRS 1915+105, XTE 1550-564 and GRO 1655-40.
Coiled tubing stimulations eliminate hole failures & condensate losses in Arun field
Bunnell, F.D.; Daud, M.M.
1995-12-31
Stimulation practices have evolved considerably over the life of the Arun Field. From the original HCl matrix treatments in the late 70`s to the organic matrix and acid fracture treatments through the early 90`s these techniques have proven effective. Beginning in recent years however, some problems have been observed. Problems include collapsing shales plugging one well and sharp drops in the condensate/gas ratio following stimulation in others. Open hole completions with a limited casing/cement barrier between the over pressured shale and the depleting Arun reservoir are subject to shale collapse and plugging when directly exposed to acid during conventional stimulations. Most Arun completions are subject to post stimulation condensate losses due to increasingly difficult conditions for effective diversion of acid treatment fluids. Acid stimulation using coiled tubing techniques effectively addresses these problems. In seven stimulations performed to date shale failures and condensate losses have been eliminated. Direct acid washing across deeper intervals helps protect the acid sensitive barrier in open hole completions and effectively treats the lower, condensate rich zones.
Biconformal symmetry and static Maxwell fields near higher-dimensional black holes
Valeri P. Frolov; Andrei Zelnikov
2015-03-30
We study an electric field created by a static electric charge near the higher dimensional Reissner-Nordstrom black hole. The relation between the static Green functions on the D-dimensional Reissner-Nordstrom background and on the (D+2)-dimensional homogeneous Bertotti-Robinson spacetime is found. Using the biconformal symmetry we obtained a simple integral representation for the static Maxwell Green functions in arbitrary dimensions. We show that in a four-dimensional spacetime the static Green function obtained by the biconformal method correctly reproduces known results. We also found a closed form for the exact static Green functions and vector potentials in the five-dimensional Reissner-Nordstrom spacetime.
Do Magnetic Fields Destroy Black Hole Accretion Disk g-Modes?
Ortega-Rodríguez, Manuel; Arguedas-Leiva, J Agustín; Wagoner, Robert V; Levine, Adam
2015-01-01
Diskoseismology, the theoretical study of normal mode oscillations in geometrically thin, optically thick accretion disks, is a strong candidate to explain some QPOs in the power spectra of many black hole X-ray binary systems. The existence of g-modes, presumably the most robust and visible of the modes, depends on general relativistic gravitational trapping in the hottest part of the disk. As the existence of the required cavity in the presence of magnetic fields has been put into doubt by theoretical calculations, we will explore in greater generality what the inclusion of magnetic fields has to say on the existence of g-modes. We use an analytical perturbative approach on the equations of MHD to assess the impact of such effects. Our main conclusion is that there appears to be no compelling reason to discard g-modes. In particular, the inclusion of a non-zero {\\it radial} component of the magnetic field enables a broader scenario for cavity non-destruction, especially taking into account recent simulation...
Probing nanoscale photo-oxidation in organic films using spatial hole burning near-field scanning from a stationary NSOM tip to induce photo-oxidation. The reduction in the fluorescence yield resulting photo-oxidation as a function of time, position, and environment free from the limits of far
Shih-Yuin Lin; B. L. Hu
2008-07-24
We study an exactly solvable model where an uniformly accelerated detector is linearly coupled to a massless scalar field initially in the Minkowski vacuum. Using the exact correlation functions we show that as soon as the coupling is switched on one can see information flowing from the detector to the field and propagating with the radiation into null infinity. By expressing the reduced density matrix of the detector in terms of the two-point functions, we calculate the purity function in the detector and study the evolution of quantum entanglement between the detector and the field. Only in the ultraweak coupling regime could some degree of recoherence in the detector appear at late times, but never in full restoration. We explicitly show that under the most general conditions the detector never recovers its quantum coherence and the entanglement between the detector and the field remains large at late times. To the extent this model can be used as an analog to the system of a black hole interacting with a quantum field, our result seems to suggest in the prevalent non-Markovian regime, assuming unitarity for the combined system, that black hole information is not lost but transferred to the quantum field degrees of freedom. Our combined system will evolve into a highly entangled state between a remnant of large area (in Bekenstein's black hole atom analog) without any information of its initial state, and the quantum field, now imbued with complex information content not-so-easily retrievable by a local observer.
Black Holes in Models with Dilaton Field and Electric or Electric and Magnetic Charges
E. Kyriakopoulos
2006-11-10
Exact static spherically symmetric charged black holes in four dimensions are presented. One of them has only electric charge and another electric and magnetic charges. In these solutions the metric is asymptotically flat, has two horizons, irremovable singularity only at $r=0$, and the dilaton field is singular only at $r=0$. The solution with electric charge only is characterized by three free parameters, the ADM mass, the electric charge and an additional free parameter. It can be considered as a modification of the GHS-GM solution obtained by changing the coupling between dilaton and electromagnetic field. The general dyonic solution is again characterized by three free parameters, the ADM mass, the magnetic charge and an additional free parameter, which is not the electric charge. According to a definition of the no-hair conjecture the solutions are "hairy".A very interesting special case of the dyonic solution is characterized by three free parameters, the ADM mass and the electric and the magnetic charges. The solutions satisfy the dominant as well as the strong energy condition outside and on the external horizon.
Xuefeng Zhang; Xinliang An
2015-10-22
Motivated by cosmic censorship in general relativity and string theory, we extend Christodoulou's celebrated examples of naked singularity formation in the Einstein-massless scalar field system to include a positive or negative scalar potential of exponential forms, i.e., $V(\\phi)=\\pm\\exp(2\\phi/\\kappa)$ with a parameter $\\kappa$. Under spherical symmetry and a self-similar ansatz depending on $\\kappa$, we derive a 3-dimensional autonomous system of first-order ordinary differential equations, which incorporates the equations for massless scalar fields as a special case. Local behavior of the phase space is studied analytically with global solutions constructed numerically. Within the 3-dimensional solution manifold, we observe, for the negative potentials, naked singularity formation from nonsingular initial data for $\\kappa^2naked singularities and black holes are also identified. However, when the potential is taken positive, numerical evolutions result in formation of black holes, but not naked singularities.
Causal extraction of black hole rotational energy by various kinds of electromagnetic fields
Koide, Shinji; Baba, Tamon
2014-09-10
Recent general relativistic magnetohydrodynamics (MHD) simulations have suggested that relativistic jets from active galactic nuclei (AGNs) have been powered by the rotational energy of central black holes. Some mechanisms for extraction of black hole rotational energy have been proposed, like the Penrose process, Blandford-Znajek mechanism, MHD Penrose process, and superradiance. The Blandford-Znajek mechanism is the most promising mechanism for the engines of the relativistic jets from AGNs. However, an intuitive interpretation of this mechanism with causality is not yet clarified, while the Penrose process has a clear interpretation for causal energy extraction from a black hole with negative energy. In this paper, we present a formula to build physical intuition so that in the Blandford-Znajek mechanism, as well as in other electromagnetic processes, negative electromagnetic energy plays an important role in causal extraction of the rotational energy of black holes.
Chen Lijen; Lefebvre, Bertrand; Torbert, Roy B.; Daughton, William S.
2011-01-15
Based on two-dimensional fully kinetic simulations that resolve the electron diffusion layer in undriven collisionless magnetic reconnection with zero guide field, this paper reports the existence and evolution of an inversion layer of bipolar electric fields, its corresponding phase-space structure (an electron-hole layer), and the implication to collisionless dissipation. The inversion electric field layer is embedded in the layer of bipolar Hall electric field and extends throughout the entire length of the electron diffusion layer. The electron phase-space hole structure spontaneously arises during the explosive growth phase when there exist significant inflows into the reconnection layer, and electrons perform meandering orbits across the layer while being cyclotron-turned toward the outflow directions. The cyclotron turning of meandering electrons by the magnetic field normal to the reconnection layer is shown to be a primary factor limiting the current density in the region where the reconnection electric field is balanced by the gradient (along the current sheet normal) of the off-diagonal electron pressure-tensor.
Alekseev, George A
2015-01-01
The exact solution of Einstein - Maxwell equations for a Schwarzschild black hole immersed in the static spatially homogeneous AdS${}^2\\times\\mathbb{S}^2$ space-time of Bertotti-Robinson magnetic universe is presented. In this solution, the black hole possesses a finite initial boost in the direction of the magnetic field and performs a "geodesic" oscillating motion interacting with the background gravitational and electromagnetic fields.
Thermodynamics of topological black holes in Brans-Dicke gravity with a power-law Maxwell field
Zangeneh, M Kord; Sheykhi, A
2015-01-01
In this paper, we present a new class of higher dimensional exact topological black hole solutions of the Brans-Dicke theory in the presence of a power-law Maxwell field as the matter source. For this aim, we introduce a conformal transformation which transforms the Einstein-dilaton-power-law Maxwell gravity Lagrangian to the Brans-Dicke-power-law Maxwell theory one. Then, by using this conformal transformation, we obtain the desired solutions. Next, we study the properties of the solutions and conditions under which we have black holes. Interestingly enough, we show that there is a cosmological horizon in the presence of a negative cosmological constant. Finally, we calculate the temperature and charge and then by calculating the Euclidean action, we obtain the mass, the entropy and the electromagnetic potential energy. We find that the entropy does not respect the area law, and also the conserved and thermodynamic quantities are invariant under conformal transformation. Using these thermodynamic and conserv...
Swensen, James S.; Wang, Liang (Frank) [Frank; Rainbolt, James E.; Koech, Phillip K.; Polikarpov, Evgueni; Gaspar, Daniel J.; Padmaperuma, Asanga B.
2012-12-01
We report a solution-processed approach for a p-type doped hole transport layer in organic light emitting devices (OLEDs). UV-vis-NIR absorption spectra identified the charge transfer between the donor and acceptor in the solution processed doped films. Single carrier device and field-effect transistor were utilized as test vehicles to study the charge transport property and extract important parameters such as bulk mobile carrier concentration and mobility. OLEDs with p-type doped hole transport layer showed significant improvement in power efficiency up to 30% at the optimal doping ratio. This approach has the great potential to reduce the power consumption for OLED solid state lighting while lowering the cost and boosting the throughput of its manufacturing.
Black Holes and Naked Singularities in Low Energy Limit of String Gravity with Modulus Field
S. Alexeyev; S. Mignemi
2001-03-16
We show that the black hole solutions of the effective string theory action, where one-loop effects that couple the moduli to gravity via a Gauss-Bonnet term are taken into account, admit primary scalar hair. The requirement of absence of naked singularities imposes an upper bound on the scalar charges.
Thermodynamics of topological black holes in Brans-Dicke gravity with a power-law Maxwell field
M. Kord Zangeneh; M. H. Dehghani; A. Sheykhi
2015-09-20
In this paper, we present a new class of higher dimensional exact topological black hole solutions of the Brans-Dicke theory in the presence of a power-law Maxwell field as the matter source. For this aim, we introduce a conformal transformation which transforms the Einstein-dilaton-power-law Maxwell gravity Lagrangian to the Brans-Dicke-power-law Maxwell theory one. Then, by using this conformal transformation, we obtain the desired solutions. Next, we study the properties of the solutions and conditions under which we have black holes. Interestingly enough, we show that there is a cosmological horizon in the presence of a negative cosmological constant. Finally, we calculate the temperature and charge and then by calculating the Euclidean action, we obtain the mass, the entropy and the electromagnetic potential energy. We find that the entropy does not respect the area law, and also the conserved and thermodynamic quantities are invariant under conformal transformation. Using these thermodynamic and conserved quantities, we show that the first law of black hole thermodynamics is satisfied on the horizon.
Zhang, Xuefeng
2015-01-01
Motivated by cosmic censorship in general relativity and string theory, we extend Christodoulou's celebrated examples of naked singularity formation in the Einstein-massless scalar field system to include a positive or negative scalar potential of exponential forms, i.e., $V(\\phi)=\\pm\\exp(2\\phi/\\kappa)$ with a parameter $\\kappa$. Under spherical symmetry and a self-similar ansatz depending on $\\kappa$, we derive a 3-dimensional autonomous system of first-order ordinary differential equations, which incorporates the equations for massless scalar fields as a special case. Local behavior of the phase space is studied analytically with global solutions constructed numerically. Within the 3-dimensional solution manifold, we observe, for the negative potentials, naked singularity formation from nonsingular initial data for $\\kappa^2naked singularities and black holes are also identified. However, when the potential is taken positive, numerical evolutions r...
Onken, Christopher A.; Ferrarese, Laura [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Valluri, Monica; Brown, Jonathan S. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); McGregor, Peter J. [Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Peterson, Bradley M.; Pogge, Richard W. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bentz, Misty C. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Office 610, Atlanta, GA 30303 (United States); Vestergaard, Marianne [Dark Cosmology Centre, The Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Storchi-Bergmann, Thaisa [Universidade Federal do Rio Grande do Sul, Instituto de Física, CP 15051, Porto Alegre 91501-970, RS (Brazil); Riffel, Rogemar A., E-mail: christopher.onken@anu.edu.au, E-mail: mvalluri@umich.edu [Departamento de Física, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil)
2014-08-10
We present a revised measurement of the mass of the central black hole (M{sub BH} ) in the Seyfert 1 galaxy NGC 4151. The new stellar dynamical mass measurement is derived by applying an axisymmetric orbit-superposition code to near-infrared integral field data obtained using adaptive optics with the Gemini Near-infrared Integral Field Spectrograph (NIFS). When our models attempt to fit both the NIFS kinematics and additional low spatial resolution kinematics, our results depend sensitively on how ?{sup 2} is computed—probably a consequence of complex bar kinematics that manifest immediately outside the nuclear region. The most robust results are obtained when only the high spatial resolution kinematic constraints in the nuclear region are included in the fit. Our best estimates for the black hole mass and H-band mass-to-light ratio are M{sub BH} ? 3.76 ± 1.15 × 10{sup 7} M{sub ?} (1? error) and Y{sub H} ? 0.34 ± 0.03 M{sub ?}/L{sub ?} (3? error), respectively (the quoted errors reflect the model uncertainties). Our black hole mass measurement is consistent with estimates from both reverberation mapping (3.57{sub ?0.37}{sup +0.45}×10{sup 7} M{sub ?}) and gas kinematics (3.0{sub ?2.2}{sup +0.75}×10{sup 7} M{sub ?}; 1? errors), and our best-fit mass-to-light ratio is consistent with the photometric estimate of Y{sub H} = 0.4 ± 0.2 M{sub ?}/L{sub ?}. The NIFS kinematics give a central bulge velocity dispersion ?{sub c} = 116 ± 3 km s{sup –1}, bringing this object slightly closer to the M{sub BH}-? relation for quiescent galaxies. Although NGC 4151 is one of only a few Seyfert 1 galaxies in which it is possible to obtain a direct dynamical black hole mass measurement—and thus, an independent calibration of the reverberation mapping mass scale—the complex bar kinematics makes it less than ideally suited for this purpose.
Hernan A. Gonzalez; David Tempo; Ricardo Troncoso
2011-07-22
Field theories with anisotropic scaling in 1+1 dimensions are considered. It is shown that the isomorphism between Lifshitz algebras with dynamical exponents z and 1/z naturally leads to a duality between low and high temperature regimes. Assuming the existence of gap in the spectrum, this duality allows to obtain a precise formula for the asymptotic growth of the number of states with a fixed energy which depends on z and the energy of the ground state, and reduces to the Cardy formula for z=1. The holographic realization of the duality can be naturally inferred from the fact that Euclidean Lifshitz spaces in three dimensions with dynamical exponents and characteristic lengths given by z, l, and 1/z, l/z, respectively, are diffeomorphic. The semiclassical entropy of black holes with Lifshitz asymptotics can then be recovered from the generalization of Cardy formula, where the ground state corresponds to a soliton. An explicit example is provided by the existence of a purely gravitational soliton solution for BHT massive gravity, which precisely has the required energy that reproduces the entropy of the analytic asymptotically Lifshitz black hole with z=3. Remarkably, neither the asymptotic symmetries nor central charges were explicitly used in order to obtain these results.
Observation of Rashba zero-field spin splitting in a strained germanium 2D hole gas
Morrison, C., E-mail: c.morrison.2@warwick.ac.uk; Rhead, S. D.; Foronda, J.; Leadley, D. R.; Myronov, M. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Wi?niewski, P. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)
2014-11-03
We report the observation, through Shubnikov-de Haas oscillations in the magnetoresistance, of spin splitting caused by the Rashba spin-orbit interaction in a strained Ge quantum well epitaxially grown on a standard Si(001) substrate. The Shubnikov-de Haas oscillations display a beating pattern due to the spin split Landau levels. The spin-orbit parameter and Rashba spin-splitting energy are found to be 1.0?×?10{sup ?28?}?eVm{sup 3} and 1.4?meV, respectively. This energy is comparable to 2D electron gases in III-V semiconductors, but substantially larger than in Si, and illustrates the suitability of Ge for modulated hole spin transport devices.
Nicholas G Phillips; B. L. Hu
2002-09-17
In Paper II [N. G. Phillips and B. L. Hu, previous abstract] we presented the details for the regularization of the noise kernel of a quantum scalar field in optical spacetimes by the modified point separation scheme, and a Gaussian approximation for the Green function. We worked out the regularized noise kernel for two examples: hot flat space and optical Schwarzschild metric. In this paper we consider noise kernels for a scalar field in the Schwarzschild black hole. Much of the work in the point separation approach is to determine how the divergent piece conformally transforms. For the Schwarzschild metric we find that the fluctuations of the stress tensor of the Hawking flux in the far field region checks with the analytic results given by Campos and Hu earlier [A. Campos and B. L. Hu, Phys. Rev. D {\\bf 58} (1998) 125021; Int. J. Theor. Phys. {\\bf 38} (1999) 1253]. We also verify Page's result [D. N. Page, Phys. Rev. {\\bf D25}, 1499 (1982)] for the stress tensor, which, though used often, still lacks a rigorous proof, as in his original work the direct use of the conformal transformation was circumvented. However, as in the optical case, we show that the Gaussian approximation applied to the Green function produces significant error in the noise kernel on the Schwarzschild horizon. As before we identify the failure as occurring at the fourth covariant derivative order.
Jho, Y. D.; Wang, X.; Reitze, D. H.; Kono, J.; Belyanin, Alexey; Kocharovsky, V. V.; Kocharovsky, Vl V.; Solomon, G. S.
2010-01-01
We present results of detailed investigations of light emission from semiconductor multiple quantum wells at low temperatures and high magnetic fields excited by intense femtosecond laser pulses. The intensity and linewidth ...
Sebastiao Mauro; Roberto Balbinot; Alessandro Fabbri; Ilya L. Shapiro
2015-04-25
We consider an auxiliary fields formulation for the general fourth-order gravity on an arbitrary curved background. The case of a Ricci-flat background is elaborated in full details and it is shown that there is an equivalence with the standard metric formulation. At the same time, using auxiliary fields helps to make perturbations to look simpler and the results more clear. As an application we reconsider the linear perturbations for the classical Schwarzschild solution. We also briefly discuss the relation to the effect of massive unphysical ghosts in the theory.
Two-dimensional inflow-wind solution of black hole accretion with an evenly symmetric magnetic field
Mosallanezhad, Amin; Yuan, Feng
2015-01-01
We solve the two-dimensional magnetohydrodynamic (MHD) equations of black hole accretion with the presence of magnetic field. The field includes a turbulent component, whose role is represented by the viscosity, and a large-scale ordered component. The latter is further assumed to be evenly symmetric with the equatorial plane. The equations are solved in the $r-\\theta$ plane of a spherical coordinate by assuming time-steady and radially self-similar. An inflow-wind solution is found. Around the equatorial plane, the gas is inflowing; while above and below the equatorial plane at a certain critical $\\theta$ angle, $\\theta\\sim 47^{\\circ}$, the inflow changes its direction of radial motion and becomes wind. The driving forces are analyzed and found to be the centrifugal force and the gradient of gas and magnetic pressure. The properties of wind are also calculated. The specific angular momentum of wind is found to be significantly larger than that of inflow, thus wind can transfer angular momentum outward. These...
K. Ghosh
2014-10-14
In this article we will discuss a Lorentzian sector calculation of the entropy of a minimally coupled scalar field in the Schwarzschild and in the Reissner-Nordstrom black hole backgrounds using the brick wall model of t' Hooft. We will use the semiclassical WKB approximation and find the possible states using the WKB quantization rule which is similar to the semiclassical Bohr-Sommerfeld quantization rule. In a previous article we found that the WKB quantization rule together with a proper counting of the states lead to a new expression for the matter field entropy which is not proportional to the area of the horizon. The expression of the entropy is logarithmically divergent in the brick wall cut-off parameter in contrary to an inverse power divergence obtained earlier. In this article we will first show that similar situation remains to be valid for the non-extreme Reissner-Nordstrom black hole background. We will next consider the modes which are not globally stationary and are confined near the horizon. The results indicate the regions in which the WKB approximation holds better and we will consider the entropy for a thin shell of matter field of a given thickness surrounding the black hole horizon. The thickness is chosen to be large compared to the Planck length. We will discuss the corresponding boundary conditions and the appropriateness of the WKB approximation using the Regge-Wheeler tortoise coordinates. When expressed in terms of a covariant cut-off parameter, the entropy of a thin shell of matter field of a given thickness and surrounding the horizon in the Schwarzschild black hole background is given by an expression proportional to the area of the black hole horizon. This leading order divergent term in the cut-off parameter remains to be logarithmically divergent.
Goshen, Utah: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New PagesSustainableGlynn County, Georgia: EnergyGorlitz AG Jump to: navigation,
Goshen, Vermont: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New PagesSustainableGlynn County, Georgia: EnergyGorlitz AG Jump to: navigation,Vermont:
Goshen North Wind Project | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsource History View New Pages RecentPlantMagma EnergyGoogle lends support to
Goshen, California: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsource History View New Pages RecentPlantMagma EnergyGoogle lends support toCalifornia:
Dilaton minimally coupled to 2 + 1 Einstein Maxwell fields; stationary cyclic symmetric black holes
A. A. Garcia-Diaz; G. Gutierrez Cano
2014-12-17
Using the Schwarzschild coordinate frame for a static cyclic symmetric metric in 2 + 1 Einstein gravity coupled to a electric Maxwell field and a dilaton logarithmically depending on the radial coordinate in the presence of an exponential potential the general solution of the Einstein Maxwell dilaton equations is derived and it is identified with the Chan Mann charged dilaton solution. Via a general SL(2;R) transformation, applied on the obtained charged dilaton metric, a family of stationary dilaton solutions has been generated; these solutions possess five parameters: dilaton and cosmological constants , charge, momentum, and mass for some values of them. All the exhibited solutions have been characterized by their quasi-local energy, mass, and momentum through their series expansions at spatial infinity. The structural functions determining these solutions increase as the radial coordinate does, hence they do not exhibit an dS AdS behavior at infinity Moreover, the algebraic structure of the Maxwell field, energy-momentum, and Cotton tensors is given explicitly.
Cranmer, Steven R
2009-01-01
Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations), and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are establish...
B. Kleihaus; J. Kunz
2000-12-20
We construct stationary black holes in SU(2) Einstein-Yang-Mills theory, which carry angular momentum and electric charge. Possessing non-trivial non-abelian magnetic fields outside their regular event horizon, they represent non-perturbative rotating hairy black holes.
Black Holes In Astronomy Black Holes In Astronomy
Wagner, Stephan
Black Hole horizon static limit ergosphere radiation magnetic fields jet jet #12;Black-hole accretion with a central bulge. #12;Click to edit Master text styles Second level Third level Fourth level Fifth level Jets and lobes of Cygnus A Carilli et al. Supermassive black holes are the most powerful engines in the Universe
Renner, Joel Lawrence; Garg, Sabodh K.; Combs, Jim
2002-06-01
Discharge from the Okuaizu boreholes is accompanied by in situ boiling. Analysis of cold-water injection and discharge data from the Okuaizu boreholes indicates that the two-phase productivity index is about an order of magnitude smaller than the injectivity index. The latter conclusion is in agreement with analyses of similar data from Oguni, Sumikawa, and Kirishima geothermal fields. A wellbore simulator was used to examine the effect of borehole diameter on the discharge capacity of geothermal boreholes with two-phase feedzones. Based on these analyses, it appears that it should be possible to deduce the discharge characteristics of largediameter wells using test data from slim holes with two-phase feeds.
Gabriel Torok; Zdenek Stuchlik
2005-02-06
Relativistic Keplerian orbital frequency and related epicyclic frequencies play an important role in physics of accretion discs orbiting Kerr black holes and can by resonant or trapping effects explain quasiperiodic oscillations observed in microquasars. Because of growing theoretical evidence on possible existence of naked singularities, we discuss behaviour of the fundamenal orbital frequencies for Keplerian motion in the field of Kerr naked singularities, primarily in order to find phenomena that could observationally distinguish a hypothetical naked singularity from black holes. Some astrophysically important consequences are sketched, namely the existence of strong resonant frequency for all Kerr naked singularities, with radial and vertical epicyclic frequencies being equal at well defined radius.
G. 't Hooft
2005-04-25
Interactions between outgoing Hawking particles and ingoing matter are determined by gravitational forces and Standard Model interactions. In particular the gravitational interactions are responsible for the unitarity of the scattering against the horizon, as dictated by the holographic principle, but the Standard Model interactions also contribute, and understanding their effects is an important first step towards a complete understanding of the horizon's dynamics. The relation between in- and outgoing states is described in terms of an operator algebra. In this paper, the first of a series, we describe the algebra induced on the horizon by U(1) vector fields and scalar fields, including the case of an Englert-Brout-Higgs mechanism, and a more careful consideration of the transverse vector field components.
M. B. Altaie
2001-05-07
In this paper we follow a new approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the gravitational field red-shifts the frequency modes of the vacuum, a condition on the minimum stregth of the gravitational field required to achieve real particle creation is derived. Application of this requirement on a Schwartzchid black hole resulted in deducing an upper limit on the region, outside the event horizon, where real particles can be created. Using this regional upper limit, and considering particle creation by black holes as a consequence of the Casimir effect, with the assumption that the created quanta are to be added to the initial energy, we deduce a natural power law for the development of the event horizon, and consequently a logarithmic law for the area spectrum of an inflating black hole. Application of the results on a cosmological model shows that if we start with a Planck-dimensional black hole, then through the process of particle creation we end up with a universe having the presently estimated critical density. Such a universe will be in a state of eternal inflation.
Black holes cannot support conformal scalar hair
T. Zannias
1994-09-14
It is shown that the only static asymptotically flat non-extrema black hole solution of the Einstein-conformally invariant scalar field equations having the scalar field bounded on the horizon, is the Schwarzschild one. Thus black holes cannot be endowed with conformal scalar hair of finite length.
Black hole Meissner effect and Blandford-Znajek jets
Penna, Robert
Spinning black holes tend to expel magnetic fields. In this way they are similar to superconductors. It has been a persistent concern that this black hole “Meissner effect” could quench jet power at high spins. This would ...
National Nuclear Security Administration (NNSA)
09%2A en Ten-Year Site Plans (TYSP) http:www.nnsa.energy.govaboutusouroperationsinfopsinfopstysp
An electromagnetic black hole made of metamaterials
Qiang Cheng; Tie Jun Cui; Wei Xiang Jiang; Ben Geng Cai
2010-04-30
Traditionally, a black hole is a region of space with huge gravitational field, which absorbs everything hitting it. In history, the black hole was first discussed by Laplace under the Newton mechanics, whose event horizon radius is the same as the Schwarzschild's solution of the Einstein's vacuum field equations. If all those objects having such an event horizon radius but different gravitational fields are called as black holes, then one can simulate certain properties of the black holes using electromagnetic fields and metamaterials due to the similar propagation behaviours of electromagnetic waves in curved space and in inhomogeneous metamaterials. In a recent theoretical work by Narimanov and Kildishev, an optical black hole has been proposed based on metamaterials, in which the theoretical analysis and numerical simulations showed that all electromagnetic waves hitting it are trapped and absorbed. Here we report the first experimental demonstration of such an electromagnetic black hole in the microwave frequencies. The proposed black hole is composed of non-resonant and resonant metamaterial structures, which can trap and absorb electromagnetic waves coming from all directions spirally inwards without any reflections due to the local control of electromagnetic fields and the event horizon corresponding to the device boundary. It is shown that the absorption rate can reach 99% in the microwave frequencies. We expect that the electromagnetic black hole could be used as the thermal emitting source and to harvest the solar light.
Black Holes and Nuclear Dynamics
David Merritt
2006-02-17
Supermassive black holes inhabit galactic nuclei, and their presence influences in crucial ways the evolution of the stellar distribution. The low-density cores observed in bright galaxies are probably a result of black hole infall, while steep density cusps like those at the Galactic center are a result of energy exchange between stars moving in the gravitational field of the single black hole. Loss-cone dynamics are substantially more complex in galactic nuclei than in collisionally-relaxed systems like globular clusters due to the wider variety of possible geometries and orbital populations. The rate of star-black hole interactions has begun to be constrained through observations of energetic events associated with stellar tidal disruptions.
Goshen County, Wyoming: Energy Resources | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New PagesSustainableGlynn County, Georgia: EnergyGorlitz AG Jump to: navigation, searchCounty,
Introduction to Black Hole Evaporation
Pierre-Henry Lambert
2014-01-16
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.
Black Holes: from Speculations to Observations
Thomas W. Baumgarte
2006-04-13
This paper provides a brief review of the history of our understanding and knowledge of black holes. Starting with early speculations on ``dark stars'' I discuss the Schwarzschild "black hole" solution to Einstein's field equations and the development of its interpretation from "physically meaningless" to describing the perhaps most exotic and yet "most perfect" macroscopic object in the universe. I describe different astrophysical black hole populations and discuss some of their observational evidence. Finally I close by speculating about future observations of black holes with the new generation of gravitational wave detectors.
Holographic Black Hole Chemistry
Andreas Karch; Brandon Robinson
2015-11-02
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 $N^2$.
Ultrafast Core-Hole Induced Dynamics in Water
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
is essential for many diverse fields, from condensed matter physics to medicine to environmental science. An incoming photon with enough energy to produce a core hole in a...
Roberto Casadio; Andrea Giugno; Octavian Micu; Alessio Orlandi
2015-11-04
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.
Zhao, Qian; Zhou, Yun-Song; Wang, Huai-Yu
2011-01-01
We investigate the mechanism of extraordinary optical transmission in subwave-length metal hole arrays. Experimental results for the arrays consisting of square or rectangle holes are well explained about the dependence of transmission strength on the polarization direction of the incident light. This polarization dependence occurs in each single-hole. For a hole array, there is in addition an interplay between the adjacent holes which is caused by the transverse magnetic field of surface plasmon polariton on the metal film surfaces. Based on the detailed study of a single-hole and two-hole structures, a simple method to calculate the total tranmissivity of hole arrays is proposed.
J. Sadeghi; Kh. Jafarzade
2015-06-23
As we know, the cosmological constant in different theories of gravity acts as a thermodynamics variable. The cosmological constant exists in different actions of gravity and also appears in the solution of such theories. These lead to use the black hole as a heat engines. Also, there are two values for the cosmological constant as positive and negative values. The case of negative cosmological constant supplies a natural realization of these engines in terms of the field theory description of the fluids to which they are holographically dual. In this paper, we are going to define heat engines for two different black holes as Dyonic BH and Kerr BH. And also, we calculate maximum efficiency for two black holes.
Spacetime constraints on accreting black holes
Garofalo, David [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California 91109 (United States)
2009-06-15
We study the spin dependence of accretion onto rotating Kerr black holes using analytic techniques. In its linear regime, angular momentum transport in MHD turbulent accretion flow involves the generation of radial magnetic field connecting plasma in a differentially rotating flow. We take a first principles approach, highlighting the constraint that limits the generation and amplification of radial magnetic fields, stemming from the transfer of energy from mechanical to magnetic form. Because the energy transferred in magnetic form is ultimately constrained by gravitational potential energy or Killing energy, the spin dependence of the latter allows us to derive spin-dependent constraints on the success of the accreting plasma to expel its angular momentum. We find an inverse relationship between this ability and black hole spin. If this radial magnetic field generation forms the basis for angular momentum transfer in accretion flows, accretion rates involving Kerr black holes are expected to be lower as the black hole spin increases in the prograde sense.
Magnetized black hole as a gravitational lens
R. A. Konoplya
2006-11-19
We use the Ernst-Schwarzschild solution for a black hole immersed in a uniform magnetic field to estimate corrections to the bending angle and time delay due-to presence of weak magnetic fields in galaxies and between galaxies, and also due-to influence of strong magnetic field near supermassive black holes. The magnetic field creates a kind of confinement in space, that leads to increasing of the bending angle and time delay for a ray of light propagating in the equatorial plane.
Fourier Analysis of the BTZ Black Hole
Ian M. Tolfree
2009-11-11
In this paper we extend our previous work regarding the role of the Fourier transformation in bulk to boundary mappings to include the BTZ black hole. We follow standard procedures for modifying Fourier Transformations to accommodate quotient spaces and arrive at a bulk to boundary mapping in a black hole background. We show that this mapping is consistent with known results and lends a new insight into the AdS/CFT duality. We find that the micro-states corresponding to the entropy of a bulk scalar field are the Fourier coefficients on the boundary, which transform under the principal series representation of $SL(2,R)$. Building upon this we present a toy model to analyze the implications of this for the origin of black hole entropy. We find that the black hole micro-states live on the boundary and correspond to the possible emission modes of the black hole
Electrically charged black hole with scalar hair
Cristian Martinez; Ricardo Troncoso
2006-06-16
An electrically charged black hole solution with scalar hair in four dimensions is presented. The self-interacting scalar field is real and it is minimally coupled to gravity and electromagnetism. The event horizon is a surface of negative constant curvature and the asymptotic region is locally an AdS spacetime. The asymptotic fall-off of the fields is slower than the standard one. The scalar field is regular everywhere except at the origin, and is supported by the presence of electric charge which is bounded from above by the AdS radius. In turn, the presence of the real scalar field smooths the electromagnetic potential everywhere. Regardless the value of the electric charge, the black hole is massless and has a fixed temperature. The entropy follows the usual area law. It is shown that there is a nonvanishing probability for the decay of the hairy black hole into a charged black hole without scalar field. Furthermore, it is found that an extremal black hole without scalar field is likely to undergo a spontaneous dressing up with a nontrivial scalar field, provided the electric charge is below a critical value.
Hickox, Ryan C.; Alexander, David M.; Goulding, Andrew D.; Myers, Adam D.; Brodwin, Mark; Forman, William R.; Jones, Christine; Murray, Stephen S.; Eisenstein, Daniel; Caldwell, Nelson; Brown, Michael J. I.; Cool, Richard J.; Kochanek, Christopher S.; Dey, Arjun; Jannuzi, Buell T.; Assef, Roberto J.; Eisenhardt, Peter R.; Gorjian, Varoujan; Stern, Daniel; Le Floc'h, Emeric
2011-04-20
We present the first measurement of the spatial clustering of mid-infrared-selected obscured and unobscured quasars, using a sample in the redshift range 0.7 < z < 1.8 selected from the 9 deg{sup 2} Booetes multiwavelength survey. Recently, the Spitzer Space Telescope and X-ray observations have revealed large populations of obscured quasars that have been inferred from models of the X-ray background and supermassive black hole evolution. To date, little is known about obscured quasar clustering, which allows us to measure the masses of their host dark matter halos and explore their role in the cosmic evolution of black holes and galaxies. In this study, we use a sample of 806 mid-infrared-selected quasars and {approx}250,000 galaxies to calculate the projected quasar-galaxy cross-correlation function w{sub p} (R). The observed clustering yields characteristic dark matter halo masses of log(M{sub halo} [h {sup -1} M{sub sun}]) = 12.7{sup +0.4}{sub -0.6} and 13.3{sup +0.3}{sub -0.4} for unobscured quasars (QSO-1s) and obscured quasars (Obs-QSOs), respectively. The results for QSO-1s are in excellent agreement with previous measurements for optically selected quasars, while we conclude that the Obs-QSOs are at least as strongly clustered as the QSO-1s. We test for the effects of photometric redshift errors on the optically faint Obs-QSOs, and find that our method yields a robust lower limit on the clustering; photo-z errors may cause us to underestimate the clustering amplitude of the Obs-QSOs by at most {approx}20%. We compare our results to previous studies, and speculate on physical implications of stronger clustering for obscured quasars.
Topological Black Holes -- Outside Looking In
R. B. Mann
1997-09-15
I describe the general mathematical construction and physical picture of topological black holes, which are black holes whose event horizons are surfaces of non-trivial topology. The construction is carried out in an arbitrary number of dimensions, and includes all known special cases which have appeared before in the literature. I describe the basic features of massive charged topological black holes in $(3+1)$ dimensions, from both an exterior and interior point of view. To investigate their interiors, it is necessary to understand the radiative falloff behaviour of a given massless field at late times in the background of a topological black hole. I describe the results of a numerical investigation of such behaviour for a conformally coupled scalar field. Significant differences emerge between spherical and higher genus topologies.
Testing black hole candidates with electromagnetic radiation
Bambi, Cosimo
2015-01-01
Astrophysical black hole candidates are thought to be the Kerr black holes of general relativity, but there is currently no direct observational evidence that the spacetime geometry around these objects is described by the Kerr solution. The study of the properties of the electromagnetic radiation emitted by gas or stars orbiting these objects can potentially test the Kerr black hole hypothesis. In this paper, I review the state of the art of this research field, describing the possible approaches to test the Kerr metric with current and future observational facilities and discussing current constraints.
Testing the Kerr black hole hypothesis
Cosimo Bambi
2011-10-13
It is thought that the final product of the gravitational collapse is a Kerr black hole and astronomers have discovered several good astrophysical candidates. While there is some indirect evidence suggesting that the latter have an event horizon, and therefore that they are black holes, a proof that the space-time around these objects is described by the Kerr geometry is still lacking. Recently, there has been an increasing interest in the possibility of testing the Kerr black hole hypothesis with present and future experiments. In this paper, I briefly review the state of the art of the field, focussing on some recent results and work in progress.
Marcelo Samuel Berman
2008-08-06
Pathria(1972) has shown, for a pressureless closed Universe, that it is inside a black (or white) hole. We show now, that the Universe with a cosmic pressure obeying Einstein's field equations, can be inside a white-hole. In the closed case, a positive cosmological constant does the job; for the flat and open cases, the condition we find is not verified for the very early Universe, but with the growth of the scale-factor, the condition will be certainly fulfilled for a positive cosmological constant, after some time. We associate the absolute temperature of the Universe, with the temperature of the corresponding white-hole.
Laura Ferrarese; David Merritt
2002-06-13
After a brief historical introduction, we summarize current efforts and accomplishments in the study of supermassive black holes.
Core Hole Drilling And Testing At The Lake City, California Geothermal...
Core Hole Drilling And Testing At The Lake City, California Geothermal Field Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Core Hole Drilling...
A Quantum Material Model of Static Schwarzschild Black Holes
S. -T. Sung
1997-03-16
A quantum-mechanical prescription of static Einstein field equation is proposed in order to construct the matter-metric eigen-states in the interior of a static Schwarzschild black hole where the signature of space-time is chosen as (--++). The spectrum of the quantum states is identified to be the integral multiples of the surface gravity. A statistical explanation of black hole entropy is given and a quantisation rule for the masses of Schwarzschild black holes is proposed.
Classical and Quantum Properties of Liouville Black Holes
R. B. Mann
1994-04-25
Black hole spacetimes can arise when a Liouville field is coupled to two- dimensional gravity. Exact solutions are obtained both classically and when quantum corrections due to back reaction effects are included. The black hole temperature depends upon the mass and 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.
Vacuum polarization for lukewarm black holes
Elizabeth Winstanley; Phil M. Young
2007-12-20
We compute the renormalized expectation value of the square of a quantum scalar field on a Reissner-Nordstrom-de Sitter black hole in which the temperatures of the event and cosmological horizons are equal (`lukewarm' black hole). Our numerical calculations for a thermal state at the same temperature as the two horizons indicate that this renormalized expectation value is regular on both the event and cosmological horizons. We are able to show analytically, using an approximation for the field modes near the horizons, that this is indeed the case.
Begelman, Mitchell C
2014-01-01
I outline the theory of accretion onto black holes, and its application to observed phenomena such as X-ray binaries, active galactic nuclei, tidal disruption events, and gamma-ray bursts. The dynamics as well as radiative signatures of black hole accretion depend on interactions between the relatively simple black-hole spacetime and complex radiation, plasma and magnetohydrodynamical processes in the surrounding gas. I will show how transient accretion processes could provide clues to these interactions. Larger global magnetohydrodynamic simulations as well as simulations incorporating plasma microphysics and full radiation hydrodynamics will be needed to unravel some of the current mysteries of black hole accretion.
Brief review on higher spin black holes
Alfredo Perez; David Tempo; Ricardo Troncoso
2014-05-12
We review some relevant results in the context of higher spin black holes in three-dimensional spacetimes, focusing on their asymptotic behaviour and thermodynamic properties. For simplicity, we mainly discuss the case of gravity nonminimally coupled to spin-3 fields, being nonperturbatively described by a Chern-Simons theory of two independent sl(3,R) gauge fields. Since the analysis is particularly transparent in the Hamiltonian formalism, we provide a concise discussion of their basic aspects in this context; and as a warming up exercise, we briefly analyze the asymptotic behaviour of pure gravity, as well as the BTZ black hole and its thermodynamics, exclusively in terms of gauge fields. The discussion is then extended to the case of black holes endowed with higher spin fields, briefly signaling the agreements and discrepancies found through different approaches. We conclude explaining how the puzzles become resolved once the fall off of the fields is precisely specified and extended to include chemical potentials, in a way that it is compatible with the asymptotic symmetries. Hence, the global charges become completely identified in an unambiguous way, so that different sets of asymptotic conditions turn out to contain inequivalent classes of black hole solutions being characterized by a different set of global charges.
Moduli Vacuum Bubbles Produced by Evaporating Black Holes
J. R. Morris
2007-08-14
We consider a model with a toroidally compactified extra dimension giving rise to a temperature-dependent 4d effective potential with one-loop contributions due to the Casimir effect, along with a 5d cosmological constant. The forms of the effective potential at low and high temperatures indicates a possibility for the formation of a domain wall bubble, formed by the modulus scalar field, surrounding an evaporating black hole. This is viewed as an example of a recently proposed black hole vacuum bubble arising from matter-sourced moduli fields in the vicinity of an evaporating black hole [D. Green, E. Silverstein, and D. Starr, Phys. Rev. D74, 024004 (2006), arXiv:hep-th/0605047]. The black hole bubble can be highly opaque to lower energy particles and photons, and thereby entrap them within. For high temperature black holes, there may also be a symmetry-breaking black hole bubble of false vacuum of the type previously conjectured by Moss [I.G. Moss, Phys. Rev. D32,1333 (1985)], tending to reflect low energy particles from its wall. A double bubble composed of these two different types of bubble may form around the black hole, altering the hole's emission spectrum that reaches outside observers. Smaller mass black holes that have already evaporated away could have left vacuum bubbles behind that contribute to the dark matter.
Solar Wind Forecasting with Coronal Holes
S. Robbins; C. J. Henney; J. W. Harvey
2007-01-09
An empirical model for forecasting solar wind speed related geomagnetic events is presented here. The model is based on the estimated location and size of solar coronal holes. This method differs from models that are based on photospheric magnetograms (e.g., Wang-Sheeley model) to estimate the open field line configuration. Rather than requiring the use of a full magnetic synoptic map, the method presented here can be used to forecast solar wind velocities and magnetic polarity from a single coronal hole image, along with a single magnetic full-disk image. The coronal hole parameters used in this study are estimated with Kitt Peak Vacuum Telescope He I 1083 nm spectrograms and photospheric magnetograms. Solar wind and coronal hole data for the period between May 1992 and September 2003 are investigated. The new model is found to be accurate to within 10% of observed solar wind measurements for its best one-month periods, and it has a linear correlation coefficient of ~0.38 for the full 11 years studied. Using a single estimated coronal hole map, the model can forecast the Earth directed solar wind velocity up to 8.5 days in advance. In addition, this method can be used with any source of coronal hole area and location data.
Valeri P. Frolov; Andrei V. Frolov
2014-12-30
We discuss a solution of the Einstein equations, obtained by gluing the external Kerr metric and the internal Weyl metric, describing an axisymmetric static vacuum distorted black hole. These metrics are glued at the null surfaces representing their horizons. For this purpose we use the formalism of massive thin null shells. The corresponding solution is called a "hybrid" black hole. The massive null shell has an angular momentum which is the origin of the rotation of the external Kerr spacetime. At the same time, the shell distorts the geometry inside the horizon. The inner geometry of the "hybrid" black hole coincides with the geometry of the interior of a non-rotating Weyl-distorted black hole. Properties of the "hybrid" black holes are briefly discussed.
Erik Curiel
2014-11-09
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 "temperature" and "entropy" enter classical thermodynamics then will suggest arguments that, I claim, show the analogy between classical black-hole mechanics and classical thermodynamics should be taken more seriously, without the need to rely on or invoke quantum mechanics. In particular, I construct an analogue of a Carnot cycle in which a black hole "couples" with an ordinary thermodynamical system in such a way that its surface gravity plays the role of temperature and its area that of entropy. Thus, the connection between classical general relativity and classical thermodynamics on their own is already deep and physically significant, independent of quantum mechanics.
Electric Charge in Interaction with Magnetically Charged Black Holes
J. H. Kim; Sei-Hoon Moon
2007-10-02
We examine the angular momentum of an electric charge e placed at rest outside a dilaton black hole with magnetic charge Q. The electromagnetic angular momentum which is stored in the electromagnetic field outside the black hole shows several common features regardless of the dilaton coupling strength, though the dilaton black holes are drastically different in their spacetime structure depending on it. First, the electromagnetic angular momentum depends on the separation distance between the two objects and changes monotonically from eQ to 0 as the charge goes down from infinity to the horizon, if rotational effects of the black hole are discarded. Next, as the black hole approaches extremality, however, the electromagnetic angular momentum tends to be independent of the distance between the two objects. It is then precisely $eQ$ as in the electric charge and monopole system in flat spacetime. We discuss why these effects are exhibited and argue that the above features are to hold in widely generic settings including black hole solutions in theories with more complicated field contents, by addressing the no hair theorem for black holes and the phenomenon of field expulsion exhibited by extremal black holes.
Extracting Energy from Black Hole through Transition Region
Li-Xin Li
2000-07-24
A new scenario for extracting energy from a Kerr black hole is proposed. With magnetic field lines connecting plasma particles inside the ergosphere with remote loads, the frame dragging twists the field lines so that energy and angular momentum are extracted from the plasma particles. If the magnetic field is strong enough, the energy extracted from the particles can be so large that the particles have negative energy as they fall into the black hole. So effectively the energy is extracted from the black hole. The particles inside the ergosphere can be continuously replenished with accretion from a disk surrounding the black hole, so a transition region with sufficient amount of plasma is formed between the black hole's horizon and the inner edge of the disk. Thus the energy can be continuously extracted from the black hole through the transition region. This may be the most efficient way for extracting energy from a Kerr black hole: in principle almost all of the rotational energy (up to $\\approx 29%$ of the total energy of the black hole) can be extracted.
Optical orientation of holes in strained nanostructures
Averkiev, N. S.; Sablina, N. I.
2008-03-15
A theory describing the optical orientation and Hanle effect for holes in quantum wells or quantum dots based on cubic semiconductors is developed. It is demonstrated that the presence of internal or external strain in quantum-confinement heterostructures leads to the dependence of the Hanle effect on the orientation of the magnetic field with respect to the heterostructure growth axis.
Black Holes and Galaxy Evolution
David Merritt
1999-10-29
Supermassive binary black holes and their influence on the structure and evolution of galaxies is reviewed.
Schwarzschild black hole in dark energy background
Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh
2014-09-27
In this paper we present an exact solution of Einstein's field equations describing the Schwarzschild black hole in dark energy background. It is also regarded as an embedded solution that the Schwarzschild black hole is embedded into the dark energy space producing Schwarzschild-dark energy black hole. It is found that the space-time geometry of Schwarzschild-dark energy solution is non-vacuum Petrov type $D$ in the classification of space-times. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor of the Schwarzschild-dark energy solution. We also find that the energy-momentum tensor of the Schwarzschild-dark energy solution violates the strong energy condition due to the negative pressure leading to a repulsive gravitational force of the matter field in the space-time. It is shown that the time-like vector field for an observer in the Schwarzschild-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity and the area of the horizons for the Schwarzschild-dark energy black hole.
Hydrodynamic model for electron-hole plasma in graphene
D. Svintsov; V. Vyurkov; S. Yurchenko; T. Otsuji; V. Ryzhii
2012-01-03
We propose a hydrodynamic model describing steady-state and dynamic electron and hole transport properties of graphene structures which accounts for the features of the electron and hole spectra. It is intended for electron-hole plasma in graphene characterized by high rate of intercarrier scattering compared to external scattering (on phonons and impurities), i.e., for intrinsic or optically pumped (bipolar plasma), and gated graphene (virtually monopolar plasma). We demonstrate that the effect of strong interaction of electrons and holes on their transport can be treated as a viscous friction between the electron and hole components. We apply the developed model for the calculations of the graphene dc conductivity, in particular, the effect of mutual drag of electrons and holes is described. The spectra and damping of collective excitations in graphene in the bipolar and monopolar limits are found. It is shown that at high gate voltages and, hence, at high electron and low hole densities (or vice-versa), the excitations are associated with the self-consistent electric field and the hydrodynamic pressure (plasma waves). In intrinsic and optically pumped graphene, the waves constitute quasineutral perturbations of the electron and hole densities (electron-hole sound waves) with the velocity being dependent only on the fundamental graphene constants.
Numerical Analysis of Black Hole Evaporation
Tsvi Piran; Andrew Strominger
1993-04-28
Black hole formation/evaporation in two-dimensional dilaton gravity can be described, in the limit where the number $N$ of matter fields becomes large, by a set of second-order partial differential equations. In this paper we solve these equations numerically. It is shown that, contrary to some previous suggestions, black holes evaporate completely a finite time after formation. A boundary condition is required to evolve the system beyond the naked singularity at the evaporation endpoint. It is argued that this may be naturally chosen so as to restore the system to the vacuum. The analysis also applies to the low-energy scattering of $S$-wave fermions by four-dimensional extremal, magnetic, dilatonic black holes.
The Environmental Impact of Supermassive Black Holes
Abraham Loeb
2004-08-10
The supermassive black holes observed at the centers of almost all present-day galaxies, had a profound impact on their environment. I highlight the principle of self-regulation, by which supermassive black holes grow until they release sufficient energy to unbind the gas that feeds them from their host galaxy. This principle explains several observed facts, including the correlation between the mass of a central black hole and the depth of the gravitational potential well of its host galaxy, and the abundance and clustering properties of bright quasars in the redshift interval of z~2-6. At lower redshifts, quasars might have limited the maximum mass of galaxies through the suppression of cooling flows in X-ray clusters. The seeds of supermassive black holes were likely planted in dwarf galaxies at redshifts z>10, through the collapse of massive or supermassive stars. The minimum seed mass can be identified observationally through the detection of gravitational waves from black hole binaries by Advanced LIGO or LISA. Aside from shaping their host galaxies, quasar outflows filled the intergalactic medium with magnetic fields and heavy elements. Beyond the reach of these outflows, the brightest quasars at z>6 have ionized exceedingly large volumes of gas (tens of comoving Mpc) prior to global reionization, and must have suppressed the faint end of the galaxy luminosity function in these volumes before the same occurred through the rest of the universe.
Weighing Black Holes in high-z SCUBA Galaxies
Alexander, D M
2006-01-01
Deep SCUBA surveys have uncovered a population of dust-enshrouded star-forming galaxies at z~2. Using the ultra-deep 2 Ms Chandra Deep Field-North survey we recently showed that a large fraction of these systems are also undergoing intense black-hole growth. Here we provide further constraints on the properties of the black holes in SCUBA galaxies using the virial black-hole mass estimator. We show that typical SCUBA galaxies are likely to host black holes with M_BH~10^7-10^8 M_solar which are accreting at, or close to, the Eddington limit. These results provide qualitative support for our earlier conclusion that the growth of the black hole lags that of the host galaxy in these massive ultraluminous galaxies.
Lagrangian perfect fluids and black hole mechanics
Vivek Iyer
1996-10-15
The first law of black hole mechanics (in the form derived by Wald), is expressed in terms of integrals over surfaces, at the horizon and spatial infinity, of a stationary, axisymmetric black hole, in a diffeomorphism invariant Lagrangian theory of gravity. The original statement of the first law given by Bardeen, Carter and Hawking for an Einstein-perfect fluid system contained, in addition, volume integrals of the fluid fields, over a spacelike slice stretching between these two surfaces. When applied to the Einstein-perfect fluid system, however, Wald's methods yield restricted results. The reason is that the fluid fields in the Lagrangian of a gravitating perfect fluid are typically nonstationary. We therefore first derive a first law-like relation for an arbitrary Lagrangian metric theory of gravity coupled to arbitrary Lagrangian matter fields, requiring only that the metric field be stationary. This relation includes a volume integral of matter fields over a spacelike slice between the black hole horizon and spatial infinity, and reduces to the first law originally derived by Bardeen, Carter and Hawking when the theory is general relativity coupled to a perfect fluid. We also consider a specific Lagrangian formulation for an isentropic perfect fluid given by Carter, and directly apply Wald's analysis. The resulting first law contains only surface integrals at the black hole horizon and spatial infinity, but this relation is much more restrictive in its allowed fluid configurations and perturbations than that given by Bardeen, Carter and Hawking. In the Appendix, we use the symplectic structure of the Einstein-perfect fluid system to derive a conserved current for perturbations of this system: this current reduces to one derived ab initio for this system by Chandrasekhar and Ferrari.
Interior of Black Holes and Information Recovery
Hikaru Kawai; Yuki Yokokura
2015-09-28
We analyze time evolution of a collapsing matter from a point of view that black holes evaporate by nature. We first consider a spherical thin shell that falls in the metric of an evaporating Schwarzschild black hole whose radius $a(t)$ decreases as $\\frac{da(t)}{dt}=-\\frac{2\\sigma(a(t))}{a(t)^2}$. The shell can never reach $a(t)$, but it approaches $a(t)+\\frac{2\\sigma(a(t))}{a(t)}$ in the time scale $\\sim a(t)$. Then the radiation from the hole is extremely weakened because of the large redshift caused by the shell. This time, however, the shell itself starts to radiate and exhausts energy. After that, the hole starts to radiate again. We can repeat this argument recursively because the motion of a shell in a spherically symmetric system is independent of the outside. In this way we can analyze a spherically symmetric collapsing matter with a general continuous distribution, and find that it evaporates without forming a trapped region. If the theory has considerably more species of matter fields, the trans-Planckian problems are avoided. There is a clear boundary at $r=a+\\frac{2\\sigma}{a}$ as the surface of the object. Although the matter distribution inside the object depends on the initial data, from the outside it looks almost the same as a conventional black hole. A strong angular pressure is induced by the Hawking radiation, because of which the matter loses energy when it collapses. We then discuss how the information of the matter is recovered in this picture. Next we consider a black hole that is adiabatically grown from a small one in the heat bath, and obtain the interior metric. We show that it is the self-consistent solution of $G_{\\mu\
Back reaction on a Reissner-Nordstro''m black hole
Wang, Bobo; Huang, Chao-guang
2001-06-15
The perturbed (''dressed'') metric of the conformally invariant scalar field in a Reissner-Nordstroem (RN) black hole is given by solving the semiclassical Einstein and Maxwell equations according to York's back-reaction approach. Some properties of the ''dressed'' black hole are obtained, such as its ''dressed'' mass, the location of the event horizon, and its surface gravity. It will also be found that the hypersurfaces of r{sub +} and r{sub {minus}} which are the event and Cauchy horizons in the ''naked'' RN black hole, become spacelike in the perturbed geometry.
Static Charged Black Hole Solutions in Horava-Lifshitz Gravity
Jin-Zhang Tang
2010-01-12
In the present work, we search static charged black hole solutions to Ho\\v{r}ava-Lifshitz gravity with or without projectability condition. We consider the most general form of action which electromagnetic field couples with Ho\\v{r}ava-Lifshitz gravity. With the projectability condition, we find dS-Reissner-Nordstrom black hole solution in Painlev\\'e-Gullstrand type coordinates in the IR region and a de-Sitter space-time solution in the UV region. Without the projectability condition, in the IR region, we find an especial static charged black hole solution.
Scalar emission in a rotating Gödel black hole
Songbai Chen; Bin Wang; Jiliang Jing
2008-08-23
We study the absorption probability and Hawking radiation of the scalar field in the rotating G\\"{o}del black hole in minimal five-dimensional gauged supergravity. We find that G\\"{o}del parameter $j$ imprints in the greybody factor and Hawking radiation. It plays a different role from the angular momentum of the black hole in the Hawking radiation and super-radiance. These information can help us know more about rotating G\\"{o}del black holes in minimal five-dimensional gauged supergravity.
Little Black Holes:Dark Matter And Ball Lightning
Mario Rabinowitz
2002-12-11
Small,quiescent black holes can be considered as candidates for the missing dark matter of the universe,and as the core energy source of ball lightning.By means of gravitational tunneling,directed radiation is emitted from black holes in a process much attenuated from that of Hawking radiation,P SH, which has proven elusive to detect.Gravitational tunneling emission is similar to electric field emission of electronsfrom a metal in that a second body is involved which lowers the barrier and gives the barrier a finite rather than infinite width.Hawking deals with a single isolated black hole.
Fontana, Peter R.; Srivastava, Rajendra P.
1973-06-01
at E = 0 is 2le I' Ib/(t)I = @~ R~R~~»nh'(IRlyt)e"'" (13)a ylal 0 5 '7 FIG. 3. Probabilities of photon emission as a function of time. The frequency corresponds to the energy differ- ence between the unperturbed degenerate excited states and the ground... states 6 is 0. 5 ey. For V= 0 the emission line is Lorentzian, but for V0 a "hole" appears at the frequency equal to the frequency difference between the excited nondecay- ing state and the ground state. The position of the "hole" is independent...
Hovering Black Holes from Charged Defects
Gary T. Horowitz; Nabil Iqbal; Jorge E. Santos; Benson Way
2015-05-05
We construct the holographic dual of an electrically charged, localised defect in a conformal field theory at strong coupling, by applying a spatially dependent chemical potential. We find that the IR behaviour of the spacetime depends on the spatial falloff of the potential. Moreover, for sufficiently localized defects with large amplitude, we find that a new gravitational phenomenon occurs: a spherical extremal charged black hole nucleates in the bulk: a hovering black hole. This is a second order quantum phase transition. We construct this new phase with several profiles for the chemical potential and study its properties. We find an apparently universal behaviour for the entropy of the defect as a function of its amplitude. We comment on the possible field theory implications of our results.
Electromagnetic quasinormal modes of D-dimensional black holes
A. López-Ortega
2006-11-02
Using the monodromy method we calculate the asymptotic quasinormal (QN) frequencies of an electromagnetic field moving in D-dimensional Schwarzschild and Schwarzschild de Sitter (SdS) black holes ($D\\geq 4$). For the D-dimensional Schwarzschild anti-de Sitter (SadS) black hole we also compute these frequencies with a similar method. Moreover, we calculate the electromagnetic normal modes of the D-dimensional anti-de Sitter (AdS) spacetime.
Mei, Jianwei
2010-10-12
. . . . . . . . . 21 1. Solutions in Four Dimensions . . . . . . . . . . . . . . 22 2. Solutions in Higher Dimensions . . . . . . . . . . . . . 27 C. Black Hole Solutions in Supergravity Theories . . . . . . . 30 D. Plebanski-Demianski Type Solutions in d = 5... is to discuss the construction of new black hole solutions and the calculation of the black hole entropy. In Chapter II, we shall re- port some new black hole solutions that we have found during the past few years [21, 22, 23] and we will discuss some...
Electromagnetic wave scattering by Schwarzschild black holes
Luís C. B. Crispino; Sam R. Dolan; Ednilton S. Oliveira
2009-05-20
We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section, and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time.
Bryan Webber
2006-04-06
In theories with large extra dimensions and TeV-scale gravity, black holes are copiously produced in particle collisions at energies well above the Planck scale. I briefly review some recent work on the phenomenology of this process, with emphasis on theoretical uncertainties and possible strategies for measuring the number of extra dimensions.
Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O
2014-01-14
There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.
Statistical Mechanics of Black Holes
B. Harms; Y. Leblanc
1992-05-11
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.
Selected stratigraphic data for drill holes located in Frenchman Flat, Nevada Test Site. Rev. 1
Drellack, S.L. Jr.
1997-02-01
Stratigraphic data are presented in tabular form for 72 holes drilled in Frenchman Flat, Nevada Test Site, between 1950 and 1993. Three pairs of data presentations are included for each hole: depth to formation tops, formation thicknesses, and formation elevations are presented in both field (English) and metric units. Also included for each hole, where available, are various construction data (hole depth, hole diameter, surface location coordinates) and certain information of hydrogeologic significance (depth to water level, top of zeolitization). The event name is given for holes associated with a particular nuclear test. An extensive set of footnotes is included, which indicates data sources and provides other information. The body of the report describes the stratigraphic setting of Frenchman Flat, gives drill-hole naming conventions and database terminology, and provides other background and reference material.
Comparing quantum black holes and naked singularities
T. P. Singh
2000-12-21
There are models of gravitational collapse in classical general relativity which admit the formation of naked singularities as well as black holes. These include fluid models as well as models with scalar fields as matter. Even if fluid models were to be regarded as unphysical in their matter content, the remaining class of models (based on scalar fields) generically admit the formation of visible regions of finite but arbitrarily high curvature. Hence it is of interest to ask, from the point of view of astrophysics, as to what a stellar collapse leading to a naked singularity (or to a visible region of very high curvature) will look like, to a far away observer. The emission of energy during such a process may be divided into three phases - (i) the classical phase, during which matter and gravity can both be treated according to the laws of classical physics, (ii) the semiclassical phase, when gravity is treated classically but matter behaves as a quantum field, and (iii) the quantum gravitational phase. In this review, we first give a summary of the status of naked singularities in classical relativity, and then report some recent results comparing the semiclassical phase of black holes with the semiclassical phase of spherical collapse leading to a naked singularity. In particular, we ask how the quantum particle creation during the collapse leading to a naked singularity compares with the Hawking radiation from a star collapsing to form a black hole. It turns out that there is a fundamental difference between the two cases. A spherical naked star emits only about one Planck energy during its semiclassical phase, and the further evolution can only be determined by the laws of quantum gravity. This contrasts with the semiclassical evaporation of a black hole.
Varying fine structure 'constant' and charged black holes
Bekenstein, Jacob D.; Schiffer, Marcelo
2009-12-15
Speculation that the fine-structure constant {alpha} varies in spacetime has a long history. We derive, in 4-D general relativity and in isotropic coordinates, the solution for a charged spherical black hole according to the framework for dynamical {alpha} J. D. Bekenstein, Phys. Rev. D 25, 1527 (1982).. This solution coincides with a previously known one-parameter extension of the dilatonic black hole family. Among the notable properties of varying-{alpha} charged black holes are adherence to a 'no hair' principle, the absence of the inner (Cauchy) horizon of the Reissner-Nordstroem black holes, the nonexistence of precisely extremal black holes, and the appearance of naked singularities in an analytic extension of the relevant metric. The exteriors of almost extremal electrically (magnetically) charged black holes have simple structures which makes their influence on applied magnetic (electric) fields transparent. We rederive the thermodynamic functions of the modified black holes; the otherwise difficult calculation of the electric potential is done by a shortcut. We confirm that variability of {alpha} in the wake of expansion of the universe does not threaten the generalized second law.
The Evolution of Accreting Black Holes in Outburst
John A. Tomsick
2004-01-12
Black hole binaries exhibit dramatic changes in their X-ray spectral and timing properties over time, providing important clues about the physical processes that occur in these systems. Black holes and black hole candidates are prime targets for RXTE with observational goals including the study of extreme gravitational fields and jet formation mechanisms. The great wealth of data from RXTE has helped us to learn about these systems as well as raising new questions about accreting black holes. RXTE observations have allowed us to study a wide range of black hole science topics including the connection between the accretion disk and jets, the geometry of the inner accretion flow, and the physical changes that occur between spectral states. In this presentation, I discuss significant results on these topics that have been obtained for persistent and transient black holes over the past several years, and I present results from our program of X-ray and radio observations during the decays of black hole transient outbursts.
Stability of black holes based on horizon thermodynamics
Meng-Sen Ma; Ren Zhao
2015-11-11
On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss-Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables $E,P,V,T,S$. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, $P=P(V,T)$. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that $P>0$ is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss-Bonnet gravity negative pressure can be feasible, but only local stable black hole exists in this case.
Juan Crisostomo; Ricardo Troncoso; Jorge Zanelli
2000-09-22
Gravitation theories selected by requiring that they have a unique anti-de Sitter vacuum with a fixed cosmological constant are studied. For a given dimension d, the Lagrangians under consideration are labeled by an integer k=1,2,...,[(d-1)/2]. Black holes for each d and k are found and are used to rank these theories. A minimum possible size for a localized electrically charged source is predicted in the whole set of theories, except General Relativity. It is found that the thermodynamic behavior falls into two classes: If d-2k=1, these solutions resemble the three dimensional black hole, otherwise, their behavior is similar to the Schwarzschild-AdS_4 geometry.
Webber, Bryan R
be presented and the effects of some of the uncertainties can be investigated. 3.1. Hawking Spectrum With the above assumptions, the spectrum of particles emitted during black hole decay takes the form dN dE ? ?E2 (eE/TH ? 1) T n+6H (8) where as usual... the trapped surface area [6, 7]. T030 02 4 6 8 10 0 0.2 0.4 0.6 0.8 1 1.2 n=0 n=1 n=2 n=6 E rS ?ˆ (0 ) ab s/ pi r2 S Figure 4: Grey-body factors for scalar emission on the brane from a (4 + n)D black hole. 0 2 4 6 8 10 0 0.2 0.4 0.6 0.8 1 1.2 n=0 n=1 n=2 n=6 E...
Dipole radiation from a cylindrical hole in the earth.
Warne, Larry Kevin; Johnson, William Arthur; Basilio, Lorena I.
2005-08-01
This report examines the problem of an antenna radiating from a cylindrical hole in the earth and the subsequent far-zone field produced in the upper air half space. The approach used for this analysis was to first examine propagation characteristics along the hole for surrounding geologic material properties. Three cases of sand with various levels of moisture content were considered as the surrounding material to the hole. For the hole diameters and sand cases examined, the radiation through the earth medium was found to be the dominant contribution to the radiation transmitted through to the upper half-space. In the analysis presented, the radiation from a vertical and a horizontal dipole source within the hole is used to determine a closed-form expression for the radiation in the earth medium which represents a modified element factor for the source and hole combination. As the final step, the well-known results for a dipole below a half space, in conjunction with the use of Snell's law to transform the modified element factor to the upper half space, determine closed-form expressions for the far-zone radiated fields in the air region above the earth.
Adaptive Finite Elements and Colliding Black Holes
Douglas N. Arnold; Arup Mukherjee; Luc Pouly
1997-09-15
According to the theory of general relativity, the relative acceleration of masses generates gravitational radiation. Although gravitational radiation has not yet been detected, it is believed that extremely violent cosmic events, such as the collision of black holes, should generate gravity waves of sufficient amplitude to detect on earth. The massive Laser Interferometer Gravitational-wave Observatory, or LIGO, is now being constructed to detect gravity waves. Consequently there is great interest in the computer simulation of black hole collisions and similar events, based on the numerical solution of the Einstein field equations. In this note we introduce the scientific, mathematical, and computational problems and discuss the development of a computer code to solve the initial data problem for colliding black holes, a nonlinear elliptic boundary value problem posed in an unbounded three dimensional domain which is a key step in solving the full field equations. The code is based on finite elements, adaptive meshes, and a multigrid solution process. Here we will particularly emphasize the mathematical and algorithmic issues arising in the generation of adaptive tetrahedral meshes.
Laura Ferrarese
2002-03-04
The purpose of this contribution is to review the current status of black hole demographics in light of recent advances in the study of high redshift QSOs (section 2), local AGNs (section 3) and local quiescent galaxies (section 4). I will then outline the prospects for future progress (section 5), and discuss what I believe will be the challenges for the years to come [ABRIDGED].
Astrophysical black holes in screened modified gravity
Davis, Anne-Christine; Jha, Rahul; Muir, Jessica; Gregory, Ruth E-mail: r.a.w.gregory@durham.ac.uk E-mail: jlmuir@umich.edu
2014-08-01
Chameleon, environmentally dependent dilaton, and symmetron gravity are three models of modified gravity in which the effects of the additional scalar degree of freedom are screened in dense environments. They have been extensively studied in laboratory, cosmological, and astrophysical contexts. In this paper, we present a preliminary investigation into whether additional constraints can be provided by studying these scalar fields around black holes. By looking at the properties of a static, spherically symmetric black hole, we find that the presence of a non-uniform matter distribution induces a non-constant scalar profile in chameleon and dilaton, but not necessarily symmetron gravity. An order of magnitude estimate shows that the effects of these profiles on in-falling test particles will be sub-leading compared to gravitational waves and hence observationally challenging to detect.
Laser stabilization using spectral hole burning
L. Rippe; B. Julsgaard; A. Walther; S. Kröll
2006-11-05
We have frequency stabilized a Coherent CR699-21 dye laser to a transient spectral hole on the 606 nm transition in Pr^{+3}:Y_2SiO_5. A frequency stability of 1 kHz has been obtained on the 10 microsecond timescale together with a long-term frequency drift below 1 kHz/s. RF magnetic fields are used to repopulate the hyperfine levels allowing us to control the dynamics of the spectral hole. A detailed theory of the atomic response to laser frequency errors has been developed which allows us to design and optimize the laser stabilization feedback loop, and specifically we give a stability criterion that must be fulfilled in order to obtain very low drift rates. The laser stability is sufficient for performing quantum gate experiments in Pr^{+3}:Y_2SiO_5.
Electromagnetic Jets from Stars and Black Holes
Samuel E. Gralla; Alexandru Lupsasca; Maria J. Rodriguez
2015-04-08
We present analytic force-free solutions modeling rotating stars and black holes immersed in the magnetic field of a thin disk that terminates at an inner radius. The solutions are exact in flat spacetime and approximate in Kerr spacetime. The compact object produces a conical jet whose properties carry information about its nature. For example, the jet from a star is surrounded by a current sheet, while that of a black hole is smooth. We compute an effective resistance in each case and compare to the canonical values used in circuit models of energy extraction. These solutions illustrate all of the basic features of the Blandford-Znajek process for energy extraction and jet formation in a clean setting.
Electromagnetic Jets from Stars and Black Holes
Gralla, Samuel E; Rodriguez, Maria J
2015-01-01
We present analytic force-free solutions modeling rotating stars and black holes immersed in the magnetic field of a thin disk that terminates at an inner radius. The solutions are exact in flat spacetime and approximate in Kerr spacetime. The compact object produces a conical jet whose properties carry information about its nature. For example, the jet from a star is surrounded by a current sheet, while that of a black hole is smooth. We compute an effective resistance in each case and compare to the canonical values used in circuit models of energy extraction. These solutions illustrate all of the basic features of the Blandford-Znajek process for energy extraction and jet formation in a clean setting.
Stable gravastars - an alternative to black holes?
Matt Visser; David L. Wiltshire
2003-12-04
The "gravastar" picture developed by Mazur and Mottola is one of a very small number of serious challenges to our usual conception of a "black hole". In the gravastar picture there is effectively a phase transition at/ near where the event horizon would have been expected to form, and the interior of what would have been the black hole is replaced by a segment of de Sitter space. While Mazur and Mottola were able to argue for the thermodynamic stability of their configuration, the question of dynamic stability against spherically symmetric perturbations of the matter or gravity fields remains somewhat obscure. In this article we construct a model that shares the key features of the Mazur-Mottola scenario, and which is sufficiently simple for a full dynamical analysis. We find that there are some physically reasonable equations of state for the transition layer that lead to stability.
Electromagnetic quasinormal modes of D-dimensional black holes II
A. López-Ortega
2007-06-20
By using the sixth order WKB approximation we calculate for an electromagnetic field propagating in D-dimensional Schwarzschild and Schwarzschild de Sitter black holes its quasinormal frequencies for the fundamental mode and first overtones. We study the dependence of these QN frequencies on the value of the cosmological constant and the spacetime dimension. We also compare with the known results for the gravitational perturbations propagating in the same background. Moreover we exactly compute the QN frequencies of the electromagnetic field propagating in D-dimensional massless topological black hole and for charged D-dimensional Nariai spacetime we exactly calculate the QN frequencies of the coupled electromagnetic and gravitational perturbations.
Anomalies, Chern-Simons Terms and Black Hole Entropy
Tatsuo Azeyanagi; R. Loganayagam; Gim Seng Ng
2015-05-11
Recent derivations of Cardy-like formulae in higher dimensional field theories have opened up a way of computing, via AdS/CFT, universal contributions to black hole entropy from gravitational Chern-Simons terms. Based on the manifestly covariant formulation of the differential Noether charge for Chern-Simons terms proposed in arXiv:1407.6364, we compute the entropy and asymptotic charges for the rotating charged AdS black holes in higher dimensions at leading order of the fluid/gravity derivative expansion in the Einstein-Maxwell-Chern-Simons system. This gives a result that exactly matches the field theory predictions from Cardy-like formulae.
Identification of Astrophysical Black Holes
Sandip K. Chakrabarti
1998-03-19
Black holes are by definition black, and therefore cannot be directly observed by using electromagnetic radiations. Convincing identification of black holes must necessarily depend on the identification of a very specially behaving matter and radiation which surround them. A major problem in this subject of black hole astrophysics is to quantify the behaviour of matter and radiation close to the horizon. In this review, the subject of black hole accretion and outflow is systematically developed. It is shown that both the stationary as well as the non-stationary properties of the observed spectra could be generally understood by these solutions. It is suggested that the solutions of radiative hydrodynamic equations may produce clear spectral signatures of black holes. Other circumstantial evidences of black holes, both in the galactic centers as well as in binary systems, are also presented.
Black holes in general relativity
Visser, Matt
2009-01-01
What is going on (as of August 2008) at the interface between theoretical general relativity, string-inspired models, and observational astrophysics? Quite a lot. In this mini-survey I will make a personal choice and focus on four specific questions: Do black holes "exist"? (For selected values of the word "exist".) Is black hole formation and evaporation unitary? Can one mimic a black hole to arbitrary accuracy? Can one detect the presence of a horizon using local physics?
Quantum Mechanics and Black Holes
Jose N. Pecina-Cruz
2005-11-27
This paper discusses the existence of black holes from the foundations of quantum mechanics. It is found that quantum mechanics rule out a possible gravitational collapse.
Energy distribution of 2+1 dimensional black holes with nonlinear electrodynamics
Leonardo Balart
2009-11-27
The energy distributions for a black hole solution resulting from coupling electrodynamics and gravity in 2+1 dimensions are obtained. This solution considers the correction for a 2+1 static charged black hole from the first contribution of the weak field limit of one loop QED in 2+1 dimensions. The Einstein and Moller energy-momentum prescriptions are used to evaluate the energy distributions associated with the mentioned 2+1 dimensional black hole and other 2+1 black hole solutions coupled with nonlinear electrodynamics. A relation that connects the coefficients of both prescriptions is established.
Zero temperature black holes and the failure of semi-classical analysis
F. G. Alvarenga; A. B. Batista; J. C. Fabris; G. T. Marques
2003-09-03
The extreme Reissner-Nordstr\\"om black holes have zero surface gravity. However, a semi-classical analysis seems to be ill-definite for these objects and apparently no notion of temperature exists for them. It is argued here that these properties are shared for all kind of black holes whose surface gravity is zero. Two examples are worked out explicitely: the scalar-tensor cold black holes and extreme black holes resulting from a gravity system coupled to a generalized Maxwell field in higher dimensions. The reasons for this anomolous behaviour are discussed as well as its thermodynamics implications.
Dilatonic wormholes: construction, operation, maintenance and collapse to black holes
Sean A. Hayward; Sung-Won Kim; Hyunjoo Lee
2001-10-18
The CGHS two-dimensional dilaton gravity model is generalized to include a ghost Klein-Gordon field, i.e. with negative gravitational coupling. This exotic radiation supports the existence of static traversible wormhole solutions, analogous to Morris-Thorne wormholes. Since the field equations are explicitly integrable, concrete examples can be given of various dynamic wormhole processes, as follows. (i) Static wormholes are constructed by irradiating an initially static black hole with the ghost field. (ii) The operation of a wormhole to transport matter or radiation between the two universes is described, including the back-reaction on the wormhole, which is found to exhibit a type of neutral stability. (iii) It is shown how to maintain an operating wormhole in a static state, or return it to its original state, by turning up the ghost field. (iv) If the ghost field is turned off, either instantaneously or gradually, the wormhole collapses into a black hole.
S. N. Dolya
2014-10-18
This article considers an opportunity of disinfecting a part of the Earth surface, occupying a large area of ten thousand square kilometers. The sunlight will cause dissociation of molecular bromine into atoms; each bromine atom kills thirty thousand molecules of ozone. Each bromine plate has a mass of forty milligrams grams and destroys ozone in the area of hundred square meters. Thus, to form the ozone hole over the area of ten thousand square kilometers, it is required to have the total mass of bromine equal to the following four tons.
Thermoelectric DC conductivities and Stokes flows on black hole horizons
Elliot Banks; Aristomenis Donos; Jerome P. Gauntlett
2015-07-15
We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.
Holographic Superconductors with Ho?ava-Lifshitz Black Holes
Rong-Gen Cai; Hai-Qing Zhang
2009-12-03
We discuss the phase transition of planar black holes in Ho\\v{r}ava-Lifshitz gravity by introducing a Maxwell field and a complex scalar field. We calculate the condensates of the charged operators in the dual CFTs when the mass square of the complex scalar filed is $m^2=-2/L^2$ and $m^2=0$, respectively. We compute the electrical conductivity of the \\hl superconductor in the probe approximation. In particular, it is found that there exists a spike in the conductivity for the case of the operator with scaling dimension one. These results are quite similar to those in the case of Schwarzschild-AdS black holes, which demonstrates that the holographic superconductivity is a robust phenomenon associated with asymptotic AdS black holes.
Thermoelectric DC conductivities and Stokes flows on black hole horizons
Banks, Elliot; Gauntlett, Jerome P
2015-01-01
We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.
Thermoelectric DC conductivities and Stokes flows on black hole horizons
Elliot Banks; Aristomenis Donos; Jerome P. Gauntlett
2015-10-11
We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For Q-lattices and one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.
Corrected form of the first law of thermodynamics for regular black holes
Meng-Sen Ma; Ren Zhao
2014-11-04
We show by explicit computations that there is a superficial inconsistency between the conventional first law of black hole thermodynamics and Bekenstein-Hawking area law for three types of regular black holes. The corrected form of the first law for these regular black holes is given. The derivation relies on the general structure of the energy-momentum tensor of the matter fields. When the black hole mass parameter $M$ is included in the energy-momentum tensor, the conventional form of the first law should be modified with an extra factor. In this case, the black hole mass $M$ can no longer be considered as the internal energy of the regular black holes.
Stability of black holes based on horizon thermodynamics
Ma, Meng-Sen
2015-01-01
On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss-Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables $E,P,V,T,S$. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, $P=P(V,T)$. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that $P>0$ is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss-Bonnet gravity negative pressure can be feasible, but only local stab...
R. B. Mann
1997-05-06
I demonstrate that, under certain circumstances, regions of negative energy density can undergo gravitational collapse into a black hole. The resultant exterior black hole spacetimes necessarily have negative mass and non-trivial topology. A full theory of quantum gravity, in which topology-changing processes take place, could give rise to such spacetimes.
The Ozone Hole Some perspective
Toohey, Darin W.
The Ozone Hole · Some perspective · The British Antarctic Survey · The "Ozone Hole" · International of the predicted ozone losses! This was quite a controversy. Ultimately, ozone losses started appearing in the late 1980s (see Figure below), but by then, there was already a credibility issue for ozone scientists. #12
A Unitary Model of The Black Hole Evaporation
Yu-Lei Feng; Yi-Xin Chen
2014-12-16
A unitary effective field model of the black hole evaporation is proposed to satisfy almost the four postulates of the black hole complementarity (BHC). In this model, we enlarge a black hole-scalar field system by adding an extra radiation detector that couples with the scalar field. After performing a partial trace over the scalar field space, we obtain an effective entanglement between the black hole and the detector (or radiation in it). As the whole system evolves, the S-matrix formula can be constructed formally step by step. Without local quantum measurements, the paradoxes of the information loss and AMPS's firewall can be resolved. However, the information can be lost due to quantum decoherence, as long as some local measurement has been performed on the detector to acquire the information of the radiation in it. But unlike Hawking's completely thermal spectrum, some residual correlations can be found in the radiations. All these considerations can be simplified in a qubit model that provides a \\emph{modified quantum teleportation} to transfer the information via an EPR pairs.
Reissner-Nordstrom black hole in dark energy background
Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh
2014-11-29
In this paper we propose a stationary solution of Einstein's field equations describing Reissner-Nordstrom black hole in dark energy background. It is to be regarded as the Reissner-Nordstrom black hole is embedded into the dark energy solution producing Reissner-Nordstrom-dark energy black hole. We find that the space-time geometry of Reissner-Nordstrom-dark energy solution is Petrov type $D$ in the classification of space-times. It is also shown that the embedded space-time possesses an energy-momentum tensor of the electromagnetic field interacting with the dark energy having negative pressure. We find the energy-momentum tensor for dark energy violates the the strong energy condition due to the negative pressure, whereas that of the electromagnetic field obeys the strong energy condition. It is shown that the time-like vector field for an observer in the Reissner-Nordstrom-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity of the horizons for the embedded dark energy black hole. The characteristic properties of relativistic dark energy based on the de Sitter solution is discussed in an appendix.
Can gravitational collapse and black-hole evaporation be a unitary process after all?
Emelyanov, Slava
2015-01-01
This paper shows a way of how one may resolve the non-unitarity problem in black-hole physics without modifications of the basic principles of local quantum field theory.
Vacuum polarisation on the brane for a higher dimensional black hole spacetime
Matthew Hewitt; Elizabeth Winstanley
2013-03-13
We present the vacuum polarisation of a massless, conformally coupled scalar field on the brane for a Schwarzschild-Tangherlini black hole in a bulk of zero to seven additional dimensions.
A scale-free analysis of magnetic holes in the solar wind
Stevens, M. L. (Michael Louis)
2006-01-01
Magnetic holes are isolated intervals of depleted interplanetary magnetic field (IMF) strength on timescales of several seconds to several hours. These intervals have been seen as often as several times per day in the ...
Asymptotically flat black holes with scalar hair: a review
Herdeiro, Carlos A R
2015-01-01
We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the spacetime symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Asymptotically flat black holes with scalar hair: a review
Carlos A. R. Herdeiro; Eugen Radu
2015-04-30
We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the spacetime symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Electromagnetic partner of the gravitational signal during accretion onto black holes
Juan Carlos Degollado; Victor Gualajara; Claudia Moreno; Darío Núñez
2014-10-21
We investigate the generation of electromagnetic and gravitational radiation in the vicinity of a perturbed Schwarzschild black hole. The gravitational perturbations and the electromagnetic field are studied by solving the Teukolsky master equation with sources, which we take to be locally charged, radially infalling, matter. Our results show that, in addition to the gravitational wave generated as the matter falls into the black hole, there is also a burst of electromagnetic radiation. This electromagnetic field has a characteristic set of quasinormal frequencies, and the gravitational radiation has the quasinormal frequencies of a Schwarzschild black hole. This scenario allows us to compare the gravitational and electromagnetic signals that are generated by a common source.
Exploring higher dimensional black holes at the large hadron collider.
Harris, Chris M.; Palmer, M. J.; Parker, Michael A.; Richardson, P.
Preprint typeset in JHEP style - HYPER VERSION Cavendish-HEP-04/29 ATL-COM-PHYS-2004-067 Exploring Higher Dimensional Black Holes at the Large Hadron Collider C.M. Harris†, M.J. Palmer†, M.A. Parker†, P. Richardson‡, A. Sabetfakhri† and B.R. Webber... the Standard Model matter and gauge fields are confined to the physical three-branes in a higher dimensional space, it has been shown that most of the black hole decay products are Standard Model quanta emitted on the brane [7] and are therefore visible...
Low energy 2+1 string gravity; black hole solutions
A. A. Garcia Diaz; G. Gutierrez Cano
2014-12-17
In this report a detailed derivation of the dynamical equations for an n dimensional heterotic string theory of the Horowitz type is carried out in the string frame and in the Einstein frame too. In particular, the dynamical equations of the three dimensional string theory are explicitly given. The relation of the Horowitz Welch and Horne Horowitz string black hole solution is exhibited. The Chan Mann charged dilaton solution is derived and the subclass of string solutions field is explicitly identified. The stationary generalization, via SL(2;R) transformations, of the static (2+1) Horne Horowitz string black hole solution is given.
Energy distribution in the dyadosphere of a charged black hole
S. S. Xulu
2003-04-22
The event horizon of a charged black hole is, according to Ruffini\\cite{Ruffini} and Preparata \\emph{et al.}\\cite{PreparataEtAl}, surrounded by a special region called the \\emph{dyadosphere} where the electromagnetic field exceeds the Euler-Heisenberg critical value for electron-positron pair production. We obtain the energy distribution in the dyadosphere region for a Reissner-Nordstr\\"{o}m black hole. We find that the energy-momentum prescriptions of Einstein, Landau-Lifshitz, Papapetrou, and Weinberg give the same and acceptable energy distribution.
Role of Disk models in Indentifying Astrophysical Black Holes
Sandip K. Chakrabarti
2005-01-14
We discuss how disk models may limit the scope of identifying astrophysical black holes. We show that the standard Keplerian thin disk model, the thick disk model, slim disks, ADAFs etc. are fundamentally limited. We present the most complete solution to date called the advective accretion disk and discuss how it has the scope to address every observational aspects of a black hole. Though the magnetic field is not fully self-consistently taken care of yet, the details with which the present model can handle various issues successfully are astounding. We present some of the examples.
Greybody factors for Myers–Perry black holes
Boonserm, Petarpa; Chatrabhuti, Auttakit Ngampitipan, Tritos; Visser, Matt
2014-11-15
The Myers–Perry black holes are higher-dimensional generalizations of the usual (3+1)-dimensional rotating Kerr black hole. They are of considerable interest in Kaluza–Klein models, specifically within the context of brane-world versions thereof. In the present article, we shall consider the greybody factors associated with scalar field excitations of the Myers–Perry spacetimes, and develop some rigorous bounds on these greybody factors. These bounds are of relevance for characterizing both the higher-dimensional Hawking radiation, and the super-radiance, that is expected for these spacetimes.
Greybody factors for Myers-Perry black holes
Boonserm, Petarpa; Ngampitipan, Tritos; Visser, Matt
2014-01-01
The Myers-Perry black holes are higher-dimensional generalizations of the usual (3+1)-dimensional rotating Kerr black hole. They are of considerable interest in Kaluza-Klein models, specifically within the context of brane-world versions thereof. In the present article we shall consider the greybody factors associated with scalar field excitations of the Myers-Perry spacetimes, and develop some rigorous bounds on these greybody factors. These bounds are of relevance for characterizing both the higher-dimensional Hawking radiation, and the super-radiance, that is expected for these spacetimes.
Strings, higher curvature corrections, and black holes
Thomas Mohaupt
2005-12-05
We review old and recent results on subleading contributions to black hole entropy in string theory.
The Woods Hole Laboratory, 1885-1985
The Woods Hole Laboratory, 1885-1985: A Century of Service Woods Hole Laboratory Northeast, Lectures, and Rededication of the Woods Hole Laboratory Contents Foreword and Acknowledgments Committees and Contributions of the Woods Hole Fisheries Laboratory Centennial Lecture II: The MBL and the Fisheries-A Century
Strong Gravitational Lensing in a Brane-World Black Hole
GuoPing Li; Biao Cao; Zhongwen Feng; Xiaotao Zu
2015-06-28
Adopting the strong field limit approach, we investigated the strong gravitational lensing in a Brane-World black hole, which means that the strong field limit coefficients and the deflection angle in this gravitational field are obtained. With this result, it can be said with certainly that the strong gravitational lensing is related to the metric of gravitational fields closely, the cosmology parameter {\\alpha} and the dark matter parameter \\b{eta} come from the Brane-World black hole exerts a great influence on it. Comparing with the Schwarzschild-AdS spacetime and the Schwarzschild-XCMD spacetime, the parameters {\\alpha}, \\b{eta} of black holes have the similar effects on the gravitational lensing. In some way, we infer that the real gravitational fields in our universe can be described by this metric, so the results of the strong gravitational lensing in this spacetime will be more reasonable for us to observe. Finally, it has to be noticed that the influence which the parameters {\\alpha}, \\b{eta} exerted on the main observable quantities of this gravitational field is discussed.
Extremal Limits of Rotating Black Holes
Laura Andrianopoli; Riccardo D'Auria; Antonio Gallerati; Mario Trigiante
2013-05-30
We consider non-extremal, stationary, axion-dilaton solutions to ungauged symmetric supergravity models, obtained by Harrison transformations of the non-extremal Kerr solution. We define a general algebraic procedure, which can be viewed as an Inonu-Wigner contraction of the Noether charge matrix associated with the effective D=3 sigma-model description of the solution, yielding, through different singular limits, the known BPS and non-BPS extremal black holes (which include the under-rotating non-BPS one). The non-extremal black hole can thus be thought of as "interpolating" among these limit-solutions. The algebraic procedure that we define generalizes the known Rasheed-Larsen limit which yielded, in the Kaluza-Klein theory, the first instance of under-rotating extremal solution. As an example of our general result, we discuss in detail the non-extremal solution in the T^3-model, with either (q_0, p^1) or (p^0, q_1) charges switched on, and its singular limits. Such solutions, computed in D=3 through the solution-generating technique, is completely described in terms of D=4 fields, which include the fully integrated vector fields.
The Behavior of a Spherical Hole in an Infinite Uniform Universe
Gilbert N. Lewis
1994-05-31
In this paper, the behavior of a spherical hole in an otherwise infinite and uniform universe is investigated. First, the Newtonian theory is developed. The concept of negative gravity, an outward gravitational force acting away from the center of the spherical hole, is presented, and the resulting expansion of the hole is investigated. Then, the same result is derived using the techniques of Einstein's theory of general relativity. The field equations are solved for an infinite uniform universe and then for an infinite universe in which matter is uniformly distributed except for a spherical hole. Negative pressure caused by negative gravity is utilized. The physical significance of the cosmological constant is explained, and a new physical concept, that of the gravitational potential of a hole, is discussed. The relationship between the Newtonian potential for a hole and the Schwarzschild solution of the field equations is explored. Finally, the geodesic equations are considered. It is shown that photons and particles are deflected away from the hole. An application of this idea is pursued, in which a new cosmology based upon expanding holes in a uniform universe is developed. The microwave background radiation and Hubble's Law, among others, are explained. Finally, current astronomical data are used to compute a remarkably accurate value of Hubble's constant, as well as estimates of the average mass density of the universe and the cosmological constant.
Black hole horizons Eric Gourgoulhon
Gourgoulhon, Eric
on a black hole: up to 42% of the mass-energy mc2 of accreted matter ! NB: thermonuclear reactions release: a very deep gravitational potential well Release of potential gravitational energy by accretion
Thermodynamics of regular black hole
Yun Soo Myung; Yong-Wan Kim; Young-Jai Park
2008-09-21
We investigate thermodynamics for a magnetically charged regular black hole (MCRBH), which comes from the action of general relativity and nonlinear electromagnetics, comparing with the Reissner-Norstr\\"om (RN) black hole in both four and two dimensions after dimensional reduction. We find that there is no thermodynamic difference between the regular and RN black holes for a fixed charge $Q$ in both dimensions. This means that the condition for either singularity or regularity at the origin of coordinate does not affect the thermodynamics of black hole. Furthermore, we describe the near-horizon AdS$_2$ thermodynamics of the MCRBH with the connection of the Jackiw-Teitelboim theory. We also identify the near-horizon entropy as the statistical entropy by using the AdS$_2$/CFT$_1$ correspondence.
You Cannot Press Out the Black Hole
Daisuke Ida; Takahiro Okamoto
2012-01-03
It is shown that a ball-shaped black hole region homeomorphic with D**n cannot be pressed out, along whichever axis penetrating the black hole region, into a black ring with a doughnut-shaped black hole region homeomorphic with S**1 x D**(n-1). A more general prohibition law for the change of the topology of black holes, including a version of no-bifurcation theorems for black holes, is given.
Distorted black holes from a vacuum 5-d spherical solution
Capistrano, Abraão J S; Ulhoa, Sergio C; Amorim, Ronni G G
2015-01-01
We study the deformation caused by the influence of extrinsic curvature on a vacuum spherically symmetric metric embedded in a 5-d bulk. In this sense, we investigate the produced stationary black-holes and derive general properties such as its mass and horizons. As an application, a test moving particle near such black-holes is also shown as well the distortion caused by extrinsic curvature on its movement. Accordingly, using asymptotically conformal flat condition on the extrinsic curvature and an analytical expansion of a set of \\emph{n}-scalar fields, we show that the resulting black holes must be large and constrained in the range $-1/2 \\leq n \\leq 1.8$ that are locally thermodynamically stable, but not globally preferred.
Black hole energy extraction via stationary scalar clouds
Wilson-Gerow, Jordan
2015-01-01
We study scalar field configurations around Kerr black holes with a time-independent energy-momentum tensor. These stationary `scalar clouds', confined near the black hole (BH) by their own mass or a mirror at fixed radius, exist at the threshold for energy extraction via superradiance. Motivated by the electromagnetic Blandford-Znajek (BZ) mechanism, we explore whether scalar clouds could serve as a proxy for the force-free magnetosphere in the BZ process. We find that a stationary energy-extracting scalar cloud solution exists when the reflecting mirror is replaced by a semi-permeable surface which allows the cloud to radiate some energy to infinity while maintaining self-sustained superradiance. The radial energy flux displays the same behaviour for rapidly rotating holes as magnetohydrodynamic simulations predict for the BZ mechanism.
Black hole energy extraction via stationary scalar clouds
Jordan Wilson-Gerow; Adam Ritz
2015-09-22
We study scalar field configurations around Kerr black holes with a time-independent energy-momentum tensor. These stationary `scalar clouds', confined near the black hole (BH) by their own mass or a mirror at fixed radius, exist at the threshold for energy extraction via superradiance. Motivated by the electromagnetic Blandford-Znajek (BZ) mechanism, we explore whether scalar clouds could serve as a proxy for the force-free magnetosphere in the BZ process. We find that a stationary energy-extracting scalar cloud solution exists when the reflecting mirror is replaced by a semi-permeable surface which allows the cloud to radiate some energy to infinity while maintaining self-sustained superradiance. The radial energy flux displays the same behaviour for rapidly rotating holes as magnetohydrodynamic simulations predict for the BZ mechanism.
Liquid Hole Multipliers: bubble-assisted electroluminescence in liquid xenon
Arazi, L; Coimbra, A E C; Rappaport, M L; Vartsky, D; Chepel, V; Breskin, A
2015-01-01
In this work we discuss the mechanism behind the large electroluminescence signals observed at relatively low electric fields in the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon. We present strong evidence that the scintillation light is generated in xenon bubbles trapped below the THGEM holes. The process is shown to be remarkably stable over months of operation, providing - under specific thermodynamic conditions - energy resolution similar to that of present dual-phase liquid xenon experiments. The observed mechanism may serve as the basis for the development of Liquid Hole Multipliers (LHMs), capable of producing local charge-induced electroluminescence signals in large-volume single-phase noble-liquid detectors for dark matter and neutrino physics experiments.
Liquid Hole Multipliers: bubble-assisted electroluminescence in liquid xenon
L. Arazi; E. Erdal; A. E. C. Coimbra; M. L. Rappaport; D. Vartsky; V. Chepel; A. Breskin
2015-05-13
In this work we discuss the mechanism behind the large electroluminescence signals observed at relatively low electric fields in the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon. We present strong evidence that the scintillation light is generated in xenon bubbles trapped below the THGEM holes. The process is shown to be remarkably stable over months of operation, providing - under specific thermodynamic conditions - energy resolution similar to that of present dual-phase liquid xenon experiments. The observed mechanism may serve as the basis for the development of Liquid Hole Multipliers (LHMs), capable of producing local charge-induced electroluminescence signals in large-volume single-phase noble-liquid detectors for dark matter and neutrino physics experiments.
Construction and physical properties of Kerr black holes with scalar hair
Carlos Herdeiro; Eugen Radu
2015-05-04
Kerr black holes with scalar hair are solutions of the Einstein-Klein-Gordon field equations describing regular (on and outside an event horizon), asymptotically flat black holes with scalar hair (arXiv:1403.2757). These black holes interpolate continuously between the Kerr solution and rotating boson stars in D=4 spacetime dimensions. Here we provide details on their construction, discussing properties of the ansatz, the field equations, the boundary conditions and the numerical strategy. Then, we present an overview of the parameter space of the solutions, and describe in detail the space-time structure of the black holes exterior geometry and of the scalar field for a sample of reference solutions. Phenomenological properties of potential astrophysical interest are also discussed, and the stability properties and possible generalizations are commented on. As supplementary material to this paper we make available numerical data files for the sample of reference solutions discussed, for public use.
Magnetically charged regular black hole in a model of nonlinear electrodynamics
Meng-Sen Ma
2015-09-18
We obtain a magnetically charged regular black hole in general relativity. The source to the Einstein field equations is nonlinear electrodynamic field in a physically reasonable model of nonlinear electrodynamics (NED). "Physically" here means the NED model is constructed on the basis of three conditions: the Maxwell asymptotic in the weak electromagnetic field limit; the presence of vacuum birefringence phenomenon; and satisfying the weak energy condition (WEC). In addition, we analyze the thermodynamic properties of the regular black hole in two ways. According to the usual black hole thermodynamics, we calculate the heat capacity at constant charge, from which we know the smaller black hole is more stable. We also employ the horizon thermodynamics to discuss the thermodynamic quantities, especially the heat capacity at constant pressure.
Magnetically charged regular black hole in a model of nonlinear electrodynamics
Ma, Meng-Sen
2015-01-01
We obtain a magnetically charged regular black hole in general relativity. The source to the Einstein field equations is nonlinear electrodynamic field in a physically reasonable model of nonlinear electrodynamics (NED). "Physically" here means the NED model is constructed on the basis of three conditions: the Maxwell asymptotic in the weak electromagnetic field limit; the presence of vacuum birefringence phenomenon; and satisfying the weak energy condition (WEC). In addition, we analyze the thermodynamic properties of the regular black hole in two ways. According to the usual black hole thermodynamics, we calculate the heat capacity at constant charge, from which we know the smaller black hole is more stable. We also employ the horizon thermodynamics to discuss the thermodynamic quantities, especially the heat capacity at constant pressure.
Cormac Breen; Adrian C. Ottewill
2011-12-13
We consider a quantum field which is in a Hartle-Hawking state propagating in a spherically symmetric black hole space-time. We calculate the components of the stress tensor, renormalized using the Hadamard form of the Green's function, in the exterior region of this space-time. We then specialize these results to the case of the `lukewarm' Riessner-Nordstrom-de Sitter black hole.
Colliding Axion-Dilaton Plane Waves from Black Holes
Patricia Schwarz
1997-08-01
The colliding plane wave metric discovered by Ferrari and Iba\\~{n}ez to be locally isometric to the interior of a Schwarzschild black hole is extended to the case of general axion-dilaton black holes. Because the transformation maps either black hole horizon to the focal plane of the colliding waves, this entire class of colliding plane wave spacetimes only suffers from the formation of spacetime singularities in the limits where the inner horizon itself is singular, which occur in the Schwarzschild and dilaton black hole limits. The supersymmetric limit corresponding to the extreme axion-dilaton black hole yields the Bertotti-Robinson metric with the axion and dilaton fields flowing to fixed constant values. The maximal analytic extension of this metric across the Cauchy horizon yields a spacetime in which two sandwich waves in a cylindrical universe collide to produce a semi-infinite chain of Reissner-Nordstrom-like wormholes. The focussing of particle and string geodesics in this spacetime is explored.
Powering AGNs with super-critical black holes
A. Avgoustidis; R. Jimenez; L. Alvarez-Gaume; M. A. Vazquez-Mozo
2009-05-13
We propose a novel mechanism for powering the central engines of Active Galactic Nuclei through super-critical (type II) black hole collapse. In this picture, ~$10^3 M_\\odot$ of material collapsing at relativistic speeds can trigger a gravitational shock, which can eject a large percentage of the collapsing matter at relativistic speeds, leaving behind a "light" black hole. In the presence of a poloidal magnetic field, the plasma collimates along two jets, and the associated electron synchrotron radiation can easily account for the observed radio luminosities, sizes and durations of AGN jets. For Lorentz factors of order 100 and magnetic fields of a few hundred $\\mu G$, synchrotron electrons can shine for $10^6$ yrs, producing jets of sizes of order 100 kpc. This mechanism may also be relevant for Gamma Ray Bursts and, in the absence of magnetic field, supernova explosions.
A. Brotas
2006-09-01
The coordinate system $(\\bar{x},\\bar{t})$ defined by $r = 2m + K\\bar{x}- c K \\bar{t}$ and $t=\\bar{x}/cK - 1 /cK \\int_{r_a}^r (1- 2m/r + K^2)^{1/2} (1 - 2m/r)^{-1}dr$ allow us to write the Schwarzschild metric in the form: \\[ds^2=c^2 d\\bar{t}^2 + (W^2/K^2 - 2W/K) d\\bar{x}^2 + 2c (1 + W/K) d\\bar{x}d\\bar{t} - r^2 (d\\theta^2 + cos^2\\theta d\\phi^2)\\] with $W=(1 - 2m/r + K^2)^{1/2}$, in which the coefficients' pathologies are moved to $r_K = 2m/(1+K^2)$. This new coordinate system is used to study the entrance into a black hole of a rigid line (a line in which the shock waves propagate with velocity c).
"Meissner effect" and Blandford-Znajek mechanism in conductive black hole magnetospheres
S. S. Komissarov; J. C. McKinney
2007-02-14
The expulsion of axisymmetric magnetic field from the event horizons of rapidly rotating black holes has been seen as an astrophysically important effect that may significantly reduce or even nullify the efficiency of the Blandford-Znajek mechanism of powering the relativistic jets in Active Galactic Nuclei and Gamma Ray Bursts. However, this Meissner-like effect is seen in vacuum solutions of black hole electrodynamics whereas the Blandford-Znajek mechanism is concerned with plasma-filled magnetospheres. In this paper we argue that conductivity dramatically changes the properties of axisymmetric electromagnetic solutions -- even for a maximally rotating Kerr black hole the magnetic field is pulled inside the event horizon. Moreover, the conditions resulting in outgoing Poynting flux in the Blandford-Znajek mechanism exist not on the event horizon but everywhere within the black hole ergosphere. Thus, the Meissner effect is unlikely to be of interest in astrophysics of black holes, at least not in the way this has been suggested so far. These conclusions are supported by the results of time-dependent numerical simulations with three different computer codes. The test problems involve black holes with the rotation parameter ranging from $a=0.999$ to $a=1$. The pure electrodynamic simulations deal with the structure of conductive magnetospheres of black holes placed in a uniform-at-infinity magnetic field (Wald's problem) and the magnetohydrodynamic simulations are used to study the magnetospheres arising in the problem of disk accretion.
SEA MUSSELS AND DOGFISH .AS FOOD By Irving A. Field
to waste. With our rapidly increasing population the capacity of the soil to produce enough foodSEA MUSSELS AND DOGFISH .AS FOOD J1. By Irving A. Field U. S. Fisheries Laboratory, Woods Hole AS FOOD. .Jl By IRVING A. FIELD, U. S. Fisheries Laboratory, Woods Hole, Mass. ~ Of the two sources
LOW-LATITUDE CORONAL HOLES, DECAYING ACTIVE REGIONS, AND GLOBAL CORONAL MAGNETIC STRUCTURE
Petrie, G. J. D. [National Solar Observatory, Tucson, AZ 85719 (United States); Haislmaier, K. J. [George Mason University, Fairfax, VA 22030 (United States)
2013-10-01
We study the relationship between decaying active-region magnetic fields, coronal holes, and the global coronal magnetic structure using Global Oscillations Network Group synoptic magnetograms, Solar TErrestrial RElations Observatory extreme-ultraviolet synoptic maps, and coronal potential-field source-surface models. We analyze 14 decaying regions and associated coronal holes occurring between early 2007 and late 2010, 4 from cycle 23 and 10 from cycle 24. We investigate the relationship between asymmetries in active regions' positive and negative magnetic intensities, asymmetric magnetic decay rates, flux imbalances, global field structure, and coronal hole formation. Whereas new emerging active regions caused changes in the large-scale coronal field, the coronal fields of the 14 decaying active regions only opened under the condition that the global coronal structure remained almost unchanged. This was because the dominant slowly varying, low-order multipoles prevented opposing-polarity fields from opening and the remnant active-region flux preserved the regions' low-order multipole moments long after the regions had decayed. Thus, the polarity of each coronal hole necessarily matched the polar field on the side of the streamer belt where the corresponding active region decayed. For magnetically isolated active regions initially located within the streamer belt, the more intense polarity generally survived to form the hole. For non-isolated regions, flux imbalance and topological asymmetry prompted the opposite to occur in some cases.
Low-latitude coronal holes, decaying active regions and global coronal magnetic structure
Petrie, Gordon
2013-01-01
We study the relationship between decaying active region magnetic fields, coronal holes and the global coronal magnetic structure using Global Oscillations Network Group (GONG) synoptic magnetograms, Solar Terrestrial RElations Observatory (STEREO) extreme ultra-violet (EUV) synoptic maps and coronal potential-field source-surface (PFSS) models. We analyze 14 decaying regions and associated coronal holes occurring between early 2007 and late 2010, four from cycle 23 and 10 from cycle 24. We investigate the relationship between asymmetries in active regions' positive and negative magnetic intensities, asymmetric magnetic decay rates, flux imbalances, global field structure and coronal hole formation. Whereas new emerging active regions caused changes in the large-scale coronal field, the coronal fields of the 14 decaying active regions only opened under the condition that the global coronal structure remained almost unchanged. This was because the dominant slowly-varying, low-order multipoles prevented opposin...
Topological black holes in Lovelock-Born-Infeld gravity
Dehghani, M. H.; Alinejadi, N.; Hendi, S. H.
2008-05-15
In this paper, we present topological black holes of third order Lovelock gravity in the presence of cosmological constant and nonlinear electromagnetic Born-Infeld field. Depending on the metric parameters, these solutions may be interpreted as black hole solutions with inner and outer event horizons, an extreme black hole or naked singularity. We investigate the thermodynamics of asymptotically flat solutions and show that the thermodynamic and conserved quantities of these black holes satisfy the first law of thermodynamic. We also endow the Ricci flat solutions with a global rotation and calculate the finite action and conserved quantities of these class of solutions by using the counterterm method. We compute the entropy through the use of the Gibbs-Duhem relation and find that the entropy obeys the area law. We obtain a Smarr-type formula for the mass as a function of the entropy, the angular momenta, and the charge, and compute temperature, angular velocities, and electric potential and show that these thermodynamic quantities coincide with their values which are computed through the use of geometry. Finally, we perform a stability analysis for this class of solutions in both the canonical and the grand-canonical ensemble and show that the presence of a nonlinear electromagnetic field and higher curvature terms has no effect on the stability of the black branes, and they are stable in the whole phase space.
Bulk emission of scalars by a rotating black hole
M. Casals; S. R. Dolan; P. Kanti; E. Winstanley
2008-07-17
We study in detail the scalar-field Hawking radiation emitted into the bulk by a higher-dimensional, rotating black hole. We numerically compute the angular eigenvalues, and solve the radial equation of motion in order to find transmission factors. The latter are found to be enhanced by the angular momentum of the black hole, and to exhibit the well-known effect of superradiance. The corresponding power spectra for scalar fields show an enhancement with the number of dimensions, as in the non-rotating case. We compute the total mass loss rate of the black hole for a variety of black-hole angular momenta and bulk dimensions, and find that, in all cases, the bulk emission remains significantly smaller than the brane emission. The angular-momentum loss rate is also computed and found to have a smaller value in the bulk than on the brane. We present accurate bulk-to-brane emission ratios for a range of scenarios.
Hadrons As Kerr-Newman Black Holes
R. L. Oldershaw
2010-03-15
The scale invariance of the source-free Einstein field equations suggests that one might be able to model hadrons as "strong gravity" black holes, if one uses an appropriate rescaling of units or a revised gravitational coupling factor. The inner consistency of this hypothesis is tested by retrodicting a close approximation to the mass of the proton from an equation that relates the angular momentum and mass of a Kerr black hole. More accurate mass and radius values for the proton are then retrodicted using the geometrodynamics form of the full Kerr-Newman solution of the Einstein-Maxwell equations. The radius of an alpha particle is calculated as an additional retrodictive test. In a third retrodictive test of the "strong gravity" hypothesis, the subatomic particle mass spectrum in the 100 MeV to 7,000 MeV range is retrodicted to a first approximation using the Kerr solution of General Relativity. The particle masses appear to form a restricted set of quantized values of the Kerr solution: n^1/2 M, where values of n are a set of discrete integers and M is the revised Planck mass. The accuracy of the 27 retrodicted masses averages 98.4%. Finally, the new atomic scale gravitational coupling constant suggests a radical revision of the assumptions governing the Planck scale, and leads to a natural explanation for the fine structure constant.
Probing the puncture for black hole simulations
J. David Brown
2009-10-23
With the puncture method for black hole simulations, the second infinity of a wormhole geometry is compactified to a single "puncture point" on the computational grid. The region surrounding the puncture quickly evolves to a trumpet geometry. The computational grid covers only a portion of the trumpet throat. It ends at a boundary whose location depends on resolution. This raises the possibility that perturbations in the trumpet geometry could propagate down the trumpet throat, reflect from the puncture boundary, and return to the black hole exterior with a resolution--dependent time delay. Such pathological behavior is not observed. This is explained by the observation that some perturbative modes propagate in the conformal geometry, others propagate in the physical geometry. The puncture boundary exists only in the physical geometry. The modes that propagate in the physical geometry are always directed away from the computational domain at the puncture boundary. The finite difference stencils ensure that these modes are advected through the boundary with no coupling to the modes that propagate in the conformal geometry. These results are supported by numerical experiments with a code that evolves spherically symmetric gravitational fields with standard Cartesian finite difference stencils. The code uses the Baumgarte--Shapiro--Shibata--Nakamura formulation of Einstein's equations with 1+log slicing and gamma--driver shift conditions.
AdS and Lifshitz Black Holes in Conformal and Einstein-Weyl Gravities
H. Lu; Y. Pang; C. N. Pope; J. Vazquez-Poritz
2012-04-14
We study black hole solutions in extended gravities with higher-order curvature terms, including conformal and Einstein-Weyl gravities. In addition to the usual AdS vacuum, the theories admit Lifshitz and Schr\\"odinger vacua. The AdS black hole in conformal gravity contains an additional parameter over and above the mass, which may be interpreted as a massive spin-2 hair. By considering the first law of thermodynamics, we find that it is necessary to introduce an associated additional intensive/extensive pair of thermodynamic quantities. We also obtain new Liftshitz black holes in conformal gravity and study their thermodynamics. We use a numerical approach to demonstrate that AdS black holes beyond the Schwarzschild-AdS solution exist in Einstein-Weyl gravity. We also demonstrate the existence of asymptotically Lifshitz black holes in Einstein-Weyl gravity. The Lifshitz black holes arise at the boundary of the parameter ranges for the AdS black holes. Outside the range, the solutions develop naked singularities. The asymptotically AdS and Lifshitz black holes provide an interesting phase transition, in the corresponding boundary field theory, from a relativistic Lorentzian system to a non-relativistic Lifshitz system.
Strings on AdS Wormholes and Nonsingular Black Holes
H. Lu; Justin F. Vazquez-Poritz; Zhibai Zhang
2014-10-22
Certain AdS black holes in the STU model can be conformally scaled to wormhole and black hole solutions of an f(R) type theory which have two asymptotically AdS regions and are completely free of curvature singularities. While there is a delta-function source for the dilaton, classical string probes are not sensitive to this singularity. If the AdS/CFT correspondence can be applied in this context, then the wormhole background describes a phase in which two copies of a conformal field theory interact with each other, whereas the nonsingular black hole describes entangled states. By studying the behavior of open strings on these backgrounds, we extract a number of features of the quarks and anti-quarks that live in the field theories. In the interacting phase, we find that there is a maximum speed with which the quarks can move without losing energy, beyond which energy is transferred from a quark in one field theory to a quark in the other. We also compute the rate at which moving quarks within entangled states lose energy to the two surrounding plasmas. While a quark-antiquark pair within a single field theory exhibits Coulomb interaction for small separation, a quark in one field theory exhibits spring-like confinement with an anti-quark in the other field theory. For the entangled states, we study how the quark-antiquark screening length depends on temperature and chemical potential. In the interacting phase of the two field theories, a quadruplet made up of one quark-antiquark pair in each field theory can undergo transitions involving how the quarks and antiquarks are paired in terms of the screening.
Energy on black hole spacetimes
Alejandro Corichi
2012-07-18
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.
Quantum Criticality and Black Holes
Sachdev, Subir [Harvard University, Cambridge, Massachusetts, United States
2009-09-01
I will describe the behavior of a variety of condensed matter systems in the vicinity of zero temperature quantum phase transitions. There is a remarkable analogy between the hydrodynamics of such systems and the quantum theory of black holes. I will show how insights from this analogy have shed light on recent experiments on the cuprate high temperature superconductors. Studies of new materials and trapped ultracold atoms are yielding new quantum phases, with novel forms of quantum entanglement. Some materials are of technological importance: e.g. high temperature superconductors. Exact solutions via black hole mapping have yielded first exact results for transport coefficients in interacting many-body systems, and were valuable in determining general structure of hydrodynamics. Theory of VBS order and Nernst effect in cuprates. Tabletop 'laboratories for the entire universe': quantum mechanics of black holes, quark-gluon plasma, neutrons stars, and big-bang physics.
Dark Matter Hawking Radiation? Dark Spinors Tunnelling in String Theory Black Holes
Cavalcanti, R T
2015-01-01
The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, that are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.
Dark Matter Hawking Radiation? Dark Spinors Tunnelling in String Theory Black Holes
R. T. Cavalcanti; Roldao da Rocha
2015-07-14
The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, that are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.
Black Holes and Galaxy Dynamics
David Merritt
1999-06-02
The consequences of nuclear black holes for the structure and dynamics of stellar spheroids are reviewed. Slow growth of a black hole in a pre-existing core produces a steep power-law density profile similar to the cusps seen in faint elliptical galaxies. The weaker cusps in bright ellipticals may result from ejection of stars by a coalescing black-hole binary; there is marginal kinematical evidence for such a process having occurred in M87. Stellar orbits in a triaxial nucleus are mostly regular at radii where the gravitational force is dominated by the black hole; however the orbital shapes are not conducive to reinforcing the triaxial figure, hence nuclei are likely to be approximately axisymmetric. In triaxial potentials, a ``zone of chaos'' extends outward to a radius where the enclosed stellar mass is roughly 100 times the mass of the black hole; in this chaotic zone, no regular, box-like orbits exist. At larger radii, the phase space in triaxial potentials is complex, consisting of stochastic orbits as well as regular orbits associated with stable resonances. Figure rotation tends to increase the degree of stochasticity. Both test-particle integrations and N-body simulations suggest that a triaxial galaxy responds globally to the presence of a central mass concentration by evolving toward more axisymmetric shapes; the evolution occurs rapidly when the mass of the central object exceeds roughly 2% of the mass in stars. The lack of significant triaxiality in most early-type galaxies may be a consequence of orbital evolution induced by nuclear black holes.
Higher dimensional dilaton black holes in the presence of exponential nonlinear electrodynamics
A. Sheykhi; A. Kazemi
2015-06-05
We examine the higher dimensional action in which gravity is coupled to the exponential nonlinear electrodynamic and a scalar dilaton field. We construct a new class of $n$-dimensional static and spherically symmetric black hole solutions of this theory in the presence of the dilaton potential with two Liouville-type terms. In the presence of two Liouville-type dilaton potential, the asymptotic behavior of the obtained black holes are neither flat nor (A)dS. Due to the nonlinear nature of electrodynamic field, the electric field has finite value near the origin where $r\\rightarrow0$ and goes to zero as $r\\rightarrow\\infty$. Interestingly enough, we find that in the absence of the dilaton field, the electric field has a finite value at $r=0$, while as soon as the dilaton field is taken into account, the electric field diverges as $r\\rightarrow 0$. This implies that the presence of the dilaton field changes the behaviour of the electric field near the origin. In the limiting case where the nonlinear parameter $\\beta$ goes to infinity, our solutions reduce to dilaton black holes of Einstein-Maxwell-dilaton gravity in higher dimensions. We compute the conserved and thermodynamic quantities of the solutions and show that these quantities satisfy the first law of black holes thermodynamics on the horizon.
A possible explanation of the clash for black hole entropy in the extremal limit
Ru-Keng Su; Bin Wang; P. K. N. Yu; E. C. M. Young
1997-11-24
It is shown that the classical entropy of the extremal black hole depends on two different limits procedures. If we first take the extremal limit and then the boundary limit, the entropy is zero; if we do it the other way round, we get the Bekenstein-Hawking entropy. By means of the brick wall model, the quantum entropy of scalar field in the extremal black hole background has been calculated for the above two different limits procedures. A possible explanation which considers the quantum effect for the clash of black hole entropy in the extremal limit is given.
Using radio emission to detect isolated and quiescent accreting black holes
Thomas J. Maccarone
2005-03-05
We discuss the implications of new relations between black holes' masses, X-ray luminosities and radio luminosities, as well as the properties of the next generation of radio telescopes, for the goal of finding isolated accreting black holes. Because accreting black holes have radio-to-X-ray flux ratios that increase with decreasing luminosity in Eddington units, and because deep surveys over large fields of view should be possible with planned instrumentation such as LOFAR, radio surveys should be significantly more efficient than X-ray surveys for finding these objects.
Scalar filed evolution and area spectrum for Lovelock-AdS black holes
C. B. Prasobh; V. C. Kuriakose
2013-10-04
We study the modes of evolution of massless scalar fields in the asymptotically AdS spacetime surrounding maximally symmetric black holes of large and intermediate size in the Lovelock model. It is observed that all modes are purely damped at higher orders. Also, the rate of damping is seen to be independent of order at higher dimensions. The asymptotic form of these frequencies for the case of large black holes is found analytically. Finally, the area spectrum for such black holes is found from these asymptotic modes.
Thermodynamics of a charged hairy black hole in (2+1) dimensions
J. Sadeghi; H. Farahani
2013-08-07
In this paper we study thermodynamics, statistics and spectroscopic aspects of a charged black hole with a scalar hair coupled to the gravity in (2+1) dimensions. We obtained effects of the black hole charge and scalar field on the thermodynamical and statistical quantities. We find that scalar charge may increase entropy, temperature and probability, while may decrease black hole mass, free and internal energy. Also electric charge increases probability and decreases temperature and internal energy. Also we investigate stability of the system and find that the thermodynamical stability exists.
Does phantom energy produce black hole?
F. Rahaman; A. Ghosh; M. Kalam
2006-12-23
We have found an exact solution of spherically symmetrical Einstein equations describing a black hole with a special type phantom energy source. It is surprising to note that our solution is analogous to Reissner-Nordstr\\"{o}m black hole.
Massive vector particles tunneling from Kerr and Kerr-Newman black holes
Li, Xiang-Qian
2015-01-01
In this paper, we investigate the Hawking radiation of massive spin-1 particles from 4-dimensional Kerr and Kerr-Newman black holes. By applying the Hamilton-Jacobi ansatz and the WKB approximation to the field equations of the massive bosons in Kerr and Kerr-Newman space-time, the quantum tunneling method is successfully implemented. As a result, we obtain the tunneling rate of the emitted vector particles and recover the standard Hawking temperature of both the two black holes.
Massive vector particles tunneling from Kerr and Kerr-Newman black holes
Xiang-Qian Li; Ge-Rui Chen
2015-07-13
In this paper, we investigate the Hawking radiation of massive spin-1 particles from 4-dimensional Kerr and Kerr-Newman black holes. By applying the Hamilton-Jacobi ansatz and the WKB approximation to the field equations of the massive bosons in Kerr and Kerr-Newman space-time, the quantum tunneling method is successfully implemented. As a result, we obtain the tunneling rate of the emitted vector particles and recover the standard Hawking temperature of both the two black holes.
Classical and thermodynamic stability of black holes
Ricardo Monteiro
2010-06-28
We consider the stability of black holes within both classical general relativity and the semiclassical thermodynamic description. In particular, we study linearised perturbations and their contribution to the gravitational partition function, addressing technical issues for charged (Reissner-Nordstrom) and rotating (Kerr-AdS) black holes. Exploring the connection between classical and thermodynamic stability, we find classical instabilities of Myers-Perry black holes and bifurcations to new black hole families.
Will black holes eventually engulf the universe?
Prado Martin-Moruno; Jose A. Jimenez Madrid; Pedro F. Gonzalez-Diaz
2006-03-28
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 models.
Hawking Emission and Black Hole Thermodynamics
Don N. Page
2006-12-18
A brief review of Hawking radiation and black hole thermodynamics is given, based largely upon hep-th/0409024.
Outgoing electromagnetic power induced from pair plasma falling into a rotating black hole
Kojima, Yasufumi
2015-01-01
We examine energy conversion from accreting pair plasma to outgoing Poynting flux by black hole rotation. Our approach is based on a two-fluid model consisting of collisionless pair plasma. The electric potential is not constant along magnetic field lines, unlike an ideal magnetohydrodynamics approximation. We show how and where longitudinal electric fields and toroidal magnetic fields are generated by the rotation, whereas they vanish everywhere for radial flow in a split monopole magnetic field in a Schwarzschild black hole. Outgoing electromagnetic power in a steady state is calculated by applying the WKB method to the perturbation equations for a small spin parameter. In our model, the luminosity has a peak in the vicinity of the black hole, but is damped toward the event horizon and infinity. The power at the peak is of the same order as that in the Blandford--Znajek process, although the physical mechanism is different.
Power Law Corrections to BTZ Black Hole Entropy
Dharm Veer Singh
2014-11-14
We study the quantum scalar field in the background of BTZ black hole and evaluate the entanglement entropy of the non-vacuum states. The entropy is proportional to the area of event horizon for the ground state, but the area law is violated in the case of non-vacuum states (first excited state and mixed states) and the corrections scale as power law.
Scattering by regular black holes: Planar massless scalar waves impinging upon a Bardeen black hole
Macedo, Caio F B; Crispino, Luís C B
2015-01-01
Singularities are common features of general relativity black holes. However, within general relativity, one can construct black holes that present no singularities. These regular black hole solutions can be achieved by, for instance, relaxing one of the energy conditions on the stress energy tensor sourcing the black hole. Some regular black hole solutions were found in the context of non-linear electrodynamics, the Bardeen black hole being the first one proposed. In this paper, we consider a planar massless scalar wave scattered by a Bardeen black hole. We compare the scattering cross section computed using a partial-wave description with the classical geodesic scattering of a stream of null geodesics, as well as with the semi-classical glory approximation. We obtain that, for some values of the corresponding black hole charge, the scattering cross section of a Bardeen black hole has a similar interference pattern of a Reissner-Nordstr\\"om black hole.
Scattering by regular black holes: Planar massless scalar waves impinging upon a Bardeen black hole
Caio F. B. Macedo; Ednilton S. de Oliveira; Luís C. B. Crispino
2015-06-26
Singularities are common features of general relativity black holes. However, within general relativity, one can construct black holes that present no singularities. These regular black hole solutions can be achieved by, for instance, relaxing one of the energy conditions on the stress energy tensor sourcing the black hole. Some regular black hole solutions were found in the context of non-linear electrodynamics, the Bardeen black hole being the first one proposed. In this paper, we consider a planar massless scalar wave scattered by a Bardeen black hole. We compare the scattering cross section computed using a partial-wave description with the classical geodesic scattering of a stream of null geodesics, as well as with the semi-classical glory approximation. We obtain that, for some values of the corresponding black hole charge, the scattering cross section of a Bardeen black hole has a similar interference pattern of a Reissner-Nordstr\\"om black hole.
New approaches to black holes Eric Gourgoulhon
Gourgoulhon, Eric
References Eric Gourgoulhon (LUTH) New approaches to black holes Okinawa Nat. Col. Tech., 17 Aug 2008 2 / 36 Gourgoulhon (LUTH) New approaches to black holes Okinawa Nat. Col. Tech., 17 Aug 2008 3 / 36 #12;Local (2006)] Eric Gourgoulhon (LUTH) New approaches to black holes Okinawa Nat. Col. Tech., 17 Aug 2008 4
High precision, rapid laser hole drilling
Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.
2013-04-02
A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.
High precision, rapid laser hole drilling
Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.
2005-03-08
A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.
High precision, rapid laser hole drilling
Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.
2007-03-20
A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.
Fenimore, Edward E.
2014-10-06
Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.
Extraordinary Transmission of Three-Dimensional Crescent-like Holes Arrays
an extraordinary optical transmission in this non-planar perforated periodic array of 3DCLH when the electric fieldExtraordinary Transmission of Three-Dimensional Crescent-like Holes Arrays Yang Shen & Mingkai Liu peak is insensitive with the incident angles and sensitive with the angle between the electric field
Phase-field modeling of switchable diode-like current-voltage ...
2014-10-12
May 7, 2014 ... concentrations of oxygen vacancies, holes, electrons, and ionized acceptors, respectively. The electric field is related to the potential through E.
Extremal Higher Spin Black Holes
Máximo Bañados; Alejandra Castro; Alberto Faraggi; Juan I. Jottar
2015-11-30
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 solutions as well. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2) + sl(3|2) Chern-Simons theory and two-dimensional CFTs with W_{(3|2)} symmetry, the simplest higher spin extension of the N=2 super-Virasoro algebra. In particular, we compute W_{(3|2)} BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N=2 two-dimensional CFTs with extended symmetry algebras.
Black hole free energy during charged collapse: a numerical study
Hugues Beauchesne; Ariel Edery
2012-05-19
We perform a numerical investigation of the thermodynamics during the collapse of a charged (complex) scalar field to a Reissner-Nordstr\\"om (RN) black hole in isotropic coordinates. Numerical work on gravitational collapse in isotropic coordinates has recently shown that the negative of the total Lagrangian approaches the Helmholtz free energy F= E-TS of a Schwarzschild black hole at late times of the collapse (where E is the black hole mass, T the temperature and S the entropy). The relevant thermodynamic potential for the RN black hole is the Gibbs free energy G=E-TS-$\\Phi_H$ Q where Q is the charge and $\\Phi_H$ the electrostatic potential at the outer horizon. In charged collapse, there is a large outgoing matter wave which prevents the exterior from settling quickly to a static state. However, the interior region is not affected significantly by the wave. We find numerically that the interior contribution to the Gibbs free energy is entirely gravitational and accumulates in a thin shell just inside the horizon. The entropy is gravitational in origin and one observes dynamically that it resides on the horizon. We also compare the numerical value of the interior Lagrangian to the expected analytical value of the interior Gibbs free energy for different initial states and we find that they agree to within 10-13%. The two values are approaching each other so that their difference decreases with more evolution time.
Sensitivity of HAWC to Primordial Black Hole Bursts
Ukwatta, T N; MacGibbon, D Stump J H; Marinelli, S S; Yapici, T; Tollefson, K
2015-01-01
Primordial Black Holes (PBHs) are black holes that may have been created in the early Universe and could be as large as supermassive black holes or as small as the Planck scale. It is believed that a black hole has a temperature inversely proportional to its mass and will thermally emit all species of fundamental particles. PBHs with initial masses of 5.0 x 10^14 g should be expiring today with bursts of high-energy gamma radiation in the GeV/TeV energy range. The High Altitude Water Cherenkov (HAWC) observatory is sensitive to the high end of the PBH gamma-ray burst spectrum. Due to its large field of view, duty cycle above 90% and sensitivity up to 100 TeV, the HAWC observatory is well suited to perform a search for PBH bursts. We report that if the PBH explodes within 0.25 light years from Earth and within 26 degrees of zenith, HAWC will have a 95% probability of detecting the PBH burst at the 5 sigma level. Conversely, a null detection from a 2 year or longer HAWC search will set PBH upper limits which ar...
On coupling impedances of pumping holes
Kurennoy, S.
1993-04-01
Coupling impedances of a single small hole in vacuum-chamber walls have been calculated at low frequencies. To generalize these results for higher frequencies and/or larger holes one needs to solve coupled integral equations for the effective currents. These equations are solved for two specific hole shapes. The effects of many holes at high frequencies where the impedances are not additive are studied using a perturbation-theory method. The periodic versus random distributions of the pumping holes in the Superconducting Super Collider liner are compared.
Black hole mimickers: Regular versus singular behavior
Lemos, Jose P. S.; Zaslavskii, Oleg B.
2008-07-15
Black hole mimickers are possible alternatives to black holes; they would look observationally almost like black holes but would have no horizon. The properties in the near-horizon region where gravity is strong can be quite different for both types of objects, but at infinity it could be difficult to discern black holes from their mimickers. To disentangle this possible confusion, we examine the near-horizon properties, and their connection with far away asymptotic properties, of some candidates to black mimickers. We study spherically symmetric uncharged or charged but nonextremal objects, as well as spherically symmetric charged extremal objects. Within the uncharged or charged but nonextremal black hole mimickers, we study nonextremal {epsilon}-wormholes on the threshold of the formation of an event horizon, of which a subclass are called black foils, and gravastars. Within the charged extremal black hole mimickers we study extremal {epsilon}-wormholes on the threshold of the formation of an event horizon, quasi-black holes, and wormholes on the basis of quasi-black holes from Bonnor stars. We elucidate whether or not the objects belonging to these two classes remain regular in the near-horizon limit. The requirement of full regularity, i.e., finite curvature and absence of naked behavior, up to an arbitrary neighborhood of the gravitational radius of the object enables one to rule out potential mimickers in most of the cases. A list ranking the best black hole mimickers up to the worst, both nonextremal and extremal, is as follows: wormholes on the basis of extremal black holes or on the basis of quasi-black holes, quasi-black holes, wormholes on the basis of nonextremal black holes (black foils), and gravastars. Since in observational astrophysics it is difficult to find extremal configurations (the best mimickers in the ranking), whereas nonextremal configurations are really bad mimickers, the task of distinguishing black holes from their mimickers seems to be less difficult than one could think of it.
Probing attosecond pulse structures by XUV-induced hole dynamics
You, Jhih-An; Dahlström, Jan Marcus
2015-01-01
We investigate a two-photon ionization process in neon by an isolated attosecond pump pulse and two coherent extreme ultraviolet probe fields. The probe fields, tuned to the 2s-2p transition in the residual ion, allow for coherent control of the photoelectron via indirect interactions with the hole. We show that the photoelectron-ion coincidence signal contains an interference pattern that can be used to reconstruct the temporal structure of attosecond pump pulses. Our results are supported by simulations based on time-dependent configuration-interaction singles and lowest-order perturbation theory within second quantization.
Temperature, Energy, and Heat Capacity of Asymptotically Anti-De Sitter Black Holes
J. D. Brown; J. Creighton; R. B. Mann
1994-05-03
We investigate the thermodynamical properties of black holes in (3+1) and (2+1) dimensional Einstein gravity with a negative cosmological constant. In each case, the thermodynamic internal energy is computed for a finite spatial region that contains the black hole. The temperature at the boundary of this region is defined by differentiating the energy with respect to entropy, and is equal to the product of the surface gravity (divided by~$2\\pi$) and the Tolman redshift factor for temperature in a stationary gravitational field. We also compute the thermodynamic surface pressure and, in the case of the (2+1) black hole, show that the chemical potential conjugate to angular momentum is equal to the proper angular velocity of the black hole with respect to observers who are at rest in the stationary time slices. In (3+1) dimensions, a calculation of the heat capacity reveals the existence of a thermodynamically stable black hole solution and a negative heat capacity instanton. This result holds in the limit that the spatial boundary tends to infinity only if the comological constant is negative; if the cosmological constant vanishes, the stable black hole solution is lost. In (2+1) dimensions, a calculation of the heat capacity reveals the existence of a thermodynamically stable black hole solution, but no negative heat capacity instanton.
N = 4 Super-Yang-Mills on Conic Space as Hologram of STU Topological Black Hole
Xing Huang; Yang Zhou
2014-09-05
We construct four-dimensional N=4 super-Yang-Mills theories on a conic sphere with various background R-symmetry gauge fields. We study free energy and supersymmetric Renyi entropy using heat kernel method as well as localization technique. We find that the universal contribution to the partition function in the free field limit is the same as that in the strong coupling limit, which implies that it may be protected by supersymmetry. Based on the fact that, the conic sphere can be conformally mapped to $S^1\\times H^3$ and the R-symmetry background fields can be supported by the R-charges of black hole, we propose that the holographic dual of these theories are five-dimensional, supersymmetric STU topological black holes. We demonstrate perfect agreement between N=4 super-Yang-Mills theories in the planar limit and the STU topological black holes.
Detecting small holes in packages
Kronberg, James W. (Aiken, SC); Cadieux, James R. (Aiken, SC)
1996-01-01
A package containing a tracer gas, and a method for determining the presence of a hole in the package by sensing the presence of the gas outside the package. The preferred tracer gas, especially for food packaging, is sulfur hexafluoride. A quantity of the gas is added to the package and the package is closed. The concentration of the gas in the atmosphere outside the package is measured and compared to a predetermined value of the concentration of the gas in the absence of the package. A measured concentration greater than the predetermined value indicates the presence of a hole in the package. Measuring may be done in a chamber having a lower pressure than that in the package.
Detecting small holes in packages
Kronberg, J.W.; Cadieux, J.R.
1996-03-19
A package containing a tracer gas, and a method for determining the presence of a hole in the package by sensing the presence of the gas outside the package are disclosed. The preferred tracer gas, especially for food packaging, is sulfur hexafluoride. A quantity of the gas is added to the package and the package is closed. The concentration of the gas in the atmosphere outside the package is measured and compared to a predetermined value of the concentration of the gas in the absence of the package. A measured concentration greater than the predetermined value indicates the presence of a hole in the package. Measuring may be done in a chamber having a lower pressure than that in the package. 3 figs.
Black Hole Thermodynamics and Electromagnetism
Burra G. Sidharth
2005-07-15
We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.
Quantum chaos inside Black Holes
Addazi, Andrea
2015-01-01
We show how semiclassical black holes can be reinterpreted as an effective geometry, composed of a large ensamble of horizonless naked singularities (eventually smoothed at the Planck scale). We call this new items {\\it frizzyballs}, which can be rigorously defined by euclidean path integral approach. This has interesting implications regarding information paradoxes. We demonstrate that infalling information will chaotically propagate inside this system before going to the full quantum gravity regime (Planck scale).
Quantum chaos inside Black Holes
Andrea Addazi
2015-08-30
We show how semiclassical black holes can be reinterpreted as an effective geometry, composed of a large ensamble of horizonless naked singularities (eventually smoothed at the Planck scale). We call this new items {\\it frizzyballs}, which can be rigorously defined by euclidean path integral approach. This has interesting implications regarding information paradoxes. We demonstrate that infalling information will chaotically propagate inside this system before going to the full quantum gravity regime (Planck scale).
Down hole periodic seismic generator
Hardee, Harry C. (Albuquerque, NM); Hills, Richard G. (Las Cruces, NM); Striker, Richard P. (Albuquerque, NM)
1989-01-01
A down hole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.
Making Clean Energy with a Kerr Black Hole: a Tokamak Model for Gamma-Ray Bursts
Li-Xin Li
2000-08-02
In this paper we present a model for making clean energy with a Kerr black hole. Consider a Kerr black hole with a dense plasma torus spinning around it. A toroidal electric current flows on the surface of the torus, which generates a poloidal magnetic field outside the torus. On the surface of the tours the magnetic field is parallel to the surface. The closed magnetic field lines winding around the torus compress and confine the plasma in the torus, as in the case of tokamaks. Though it is unclear if such a model is stable, we look into the consequences if the model is stable. If the magnetic field is strong enough, the baryonic contamination from the plasma in the torus is greatly suppressed by the magnetic confinement and a clean magnetosphere of electron-positron pairs is built up around the black hole. Since there are no open magnetic field lines threading the torus and no accretion, the power of the torus is zero. If some magnetic field lines threading the black hole are open and connect with loads, clean energy can be extracted from the Kerr black hole by the Blandford-Znajek mechanism. The model may be relevant to gamma-ray bursts. The energy in the Poynting flux produced by the Blandford-Znajek mechanism is converted into the kinetic energy of the electron-positron pairs in the magnetosphere around the black hole, which generates two oppositely directed jets of electron-positron pairs with super-high bulk Lorentz factors. The jets collide and interact with the interstellar medium, which may produce gamma-ray bursts and the afterglows.
Thermodynamics of black holes in (n+1)-dimensional Einstein-Born-Infeld-dilaton gravity
Sheykhi, A.; Riazi, N.
2007-01-15
We construct a new class of (n+1)-dimensional (n{>=}3) black hole solutions in Einstein-Born-Infeld-dilaton gravity with Liouville-type potential for the dilaton field and investigate their properties. These solutions are neither asymptotically flat nor (anti)-de Sitter. We find that these solutions can represent black holes, with inner and outer event horizons, an extreme black hole, or a naked singularity provided the parameters of the solutions are chosen suitably. We compute the thermodynamic quantities of the black hole solutions and find that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis and investigate the effect of dilaton on the stability of the solutions.
Rotating black holes in a draining bathtub: superradiant scattering of gravity waves
Mauricio Richartz; Angus Prain; Stefano Liberati; Silke Weinfurtner
2015-06-05
In a draining rotating fluid flow background, surface perturbations behave as a scalar field on a rotating effective black hole spacetime. We propose a new model for the background flow which takes into account the varying depth of the water. Numerical integration of the associated Klein-Gordon equation using accessible experimental parameters shows that gravity waves in an appropriate frequency range are amplified through the mechanism of superradiance. Our numerical results suggest that the observation of this phenomenon in a common fluid mechanical system is within experimental reach. Unlike the case of wave scattering around Kerr black holes, which depends only on one dimensionless background parameter (the ratio $a/M$ between the specific angular momentum and the mass of the black hole), our system depends on two dimensionless background parameters, namely the normalized angular velocity and surface gravity at the effective black hole horizon.
An introduction to local Black Hole horizons in the 3+1 approach to General Relativity
José Luis Jaramillo
2011-08-11
We present an introduction to dynamical trapping horizons as quasi-local models for black hole horizons, from the perspective of an Initial Value Problem approach to the construction of generic black hole spacetimes. We focus on the geometric and structural properties of these horizons aiming, as a main application, at the numerical evolution and analysis of black hole spacetimes in astrophysical scenarios. In this setting, we discuss their dual role as an "a priori" ingredient in certain formulations of Einstein equations and as an "a posteriori" tool for the diagnosis of dynamical black hole spacetimes. Complementary to the first-principles discussion of quasi-local horizon physics, we place an emphasis on the "rigidity" properties of these hypersurfaces and their role as privileged geometric probes into near-horizon strong-field spacetime dynamics.
Submicron patterned metal hole etching
McCarthy, Anthony M. (Menlo Park, CA); Contolini, Robert J. (Lake Oswego, OR); Liberman, Vladimir (Needham, MA); Morse, Jeffrey (Martinez, CA)
2000-01-01
A wet chemical process for etching submicron patterned holes in thin metal layers using electrochemical etching with the aid of a wetting agent. In this process, the processed wafer to be etched is immersed in a wetting agent, such as methanol, for a few seconds prior to inserting the processed wafer into an electrochemical etching setup, with the wafer maintained horizontal during transfer to maintain a film of methanol covering the patterned areas. The electrochemical etching setup includes a tube which seals the edges of the wafer preventing loss of the methanol. An electrolyte composed of 4:1 water: sulfuric is poured into the tube and the electrolyte replaces the wetting agent in the patterned holes. A working electrode is attached to a metal layer of the wafer, with reference and counter electrodes inserted in the electrolyte with all electrodes connected to a potentiostat. A single pulse on the counter electrode, such as a 100 ms pulse at +10.2 volts, is used to excite the electrochemical circuit and perform the etch. The process produces uniform etching of the patterned holes in the metal layers, such as chromium and molybdenum of the wafer without adversely effecting the patterned mask.
Dyonic AdS_4 black hole entropy and attractors via entropy function
Goulart, Prieslei
2015-01-01
Using the Sen's entropy function formalism, we compute the entropy for the extremal dyonic black hole solutions of theories in the presence of dilaton field coupled to the field strength and a dilaton potential. We solve the attractor equations analytically and determine the near horizon metric, the value of the scalar fields and the electric field on the horizon, and consequently the entropy of these black holes. The attractor mechanism plays a very important role for these systems, and after studying the simplest systems involving dilaton fields, we propose a general ansatz for the value of the scalar field on the horizon, which allows us to solve the attractor equations for gauged supergravity theories in AdS_4 spaces.
Are black holes in an ekpyrotic phase possible?
J. C. S. Neves
2015-09-10
The ekpyrotic phase (a slow contraction cosmic phase before the current expansion phase) manages to solve the main problems of the standard cosmology by means of a scalar field interpreted as an isotropic cosmic fluid in the Friedmann equation. Moreover, this phase generates a nearly scale-invariant spectrum of perturbations in agreement with the latest data. Then, the ekpyrotic mechanism is a serious possibility to the inflationary model. In this work, we point out that it is impossible to generate a black hole with spherical symmetry supported by an isotropic fluid in this scenario. Using the approach of deforming metrics to obtain solutions with an isotropic energy-momentum tensor, we show that the stiff fluid, dominant in the ekpyrotic phase, does not support these black holes.
Black hole lightning due to particle acceleration at subhorizon scales
Aleksi?, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Godinovi?, N; Muñoz, A González; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzi?, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J
2014-01-01
Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here, we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20\\% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.
CP Violation and Baryogenesis in the Presence of Black Holes
Tom Banks; Willy Fischler
2015-05-16
In a recent paper[1] Kundu and one of the present authors showed that there were transient but observable CP violating effects in the decay of classical currents on the horizon of a black hole, if the Lagrangian of the Maxwell field contained a CP violating angle {\\theta}. In this paper we demonstrate that a similar effect can be seen in the quantum mechanics of QED: a non-trivial Berry phase in the QED wave function is produced by in-falling electric charges. We also investigate whether CP violation, of this or any other type, might be used to produce the baryon asymmetry of the universe, in models where primordial black hole decay contributes to the matter content of the present universe. This can happen both in a variety of hybrid inflation models, and in the Holographic Space-time (HST) model of inflation[2].
Can accretion disk properties observationally distinguish black holes from naked singularities?
Z. Kovacs; T. Harko
2010-12-06
Naked singularities are hypothetical astrophysical objects, characterized by a gravitational singularity without an event horizon. Penrose has proposed a conjecture, according to which there exists a cosmic censor who forbids the occurrence of naked singularities. Distinguishing between astrophysical black holes and naked singularities is a major challenge for present day observational astronomy. A possibility of differentiating naked singularities from black holes is through the comparative study of thin accretion disks properties around rotating naked singularities and Kerr-type black holes, respectively. In the present paper, we consider accretion disks around rotating naked singularities, obtained as solutions of the field equations in the Einstein-massless scalar field theory. A first major difference between rotating naked singularities and Kerr black holes is in the frame dragging effect, the angular velocity of a rotating naked singularity being inversely proportional to its spin parameter. Due to the differences in the exterior geometry, the thermodynamic and electromagnetic properties of the disks are different for these two classes of compact objects, consequently giving clear observational signatures that could discriminate between black holes and naked singularities. For specific values of the spin parameter and of the scalar charge, the energy flux from the disk around a rotating naked singularity can exceed by several orders of magnitude the flux from the disk of a Kerr black hole. The conversion efficiency of the accreting mass into radiation by rotating naked singularities is always higher than the conversion efficiency for black holes. Thus, these observational signatures may provide the necessary tools from clearly distinguishing rotating naked singularities from Kerr-type black holes.
An Exact Hairy Black Hole Solution for AdS/CFT Superconductors
Ding-fang Zeng
2009-08-30
We provide an exact hairy black hole solution to an $n+1$ dimensional complex scalar field model coupled with gravity. The model is characterized by a potential with one parameter. Depending on the magnitude of this parameter, the effective mass square of the scalar field can be both positive and negative. No matter what case it is, there are temperature ranges in which the hairy black hole is thermodynamically stable against decaying into its no-hair counterpart. We use this solution as an AdS/CFT superconductor model and study its conductivity-frequency relation and find typical features observed in other AdS/CFT superconductor models.
Relationship of Black Holes to Bulges
David Merritt; Laura Ferrarese
2001-07-08
Supermassive black holes appear to be uniquely associated with galactic bulges. The mean ratio of black hole mass to bulge mass was until recently very uncertain, with ground based, stellar kinematical data giving a value roughly an order of magnitude larger than other techniques. The discrepancy was resolved with the discovery of the M-sigma relation, which simultaneously established a tight corrrelation between black hole mass and bulge velocity dispersion, and confirmed that the stellar kinematical mass estimates were systematically too large due to failure to resolve the black hole's sphere of influence. There is now excellent agreement between the various techniques for estimating the mean black hole mass, including dynamical mass estimation in quiescent galaxies; reverberation mapping in active galaxies and quasars; and computation of the mean density of compact objects based on integrated quasar light. Implications of the M-sigma relation for the formation of black holes are discussed.
Boson shells harboring charged black holes
Kleihaus, Burkhard; Kunz, Jutta; Laemmerzahl, Claus; List, Meike
2010-11-15
We consider boson shells in scalar electrodynamics coupled to Einstein gravity. The interior of the shells can be empty space, or harbor a black hole or a naked singularity. We analyze the properties of these types of solutions and determine their domains of existence. We investigate the energy conditions and present mass formulae for the composite black hole-boson shell systems. We demonstrate that these types of solutions violate black hole uniqueness.
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Free-fall Frame
Peng Wang; Haitang Yang; Shuxuan Ying
2015-05-18
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass $m_{p}$. The corrections to the Hawking temperature are calculated for massive and charged particles to $\\mathcal{O}\\left( m_{p}^{-2}\\right) $ and neutral and massless particles with $\\lambda=0$ to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation.
Lower Dimensional Black Holes: Inside and Out
R. B. Mann
1995-01-27
I survey the physics of black holes in two and three spacetime dimensions, with special attention given to an understanding of their exterior and interior properties.
Rotating Black Holes and Coriolis Effect
Wu, Xiaoning; Yuan, Pei-Hung; Cho, Chia-Jui
2015-01-01
In this work, we consider the fluid/gravity correspondence for general rotating black holes. By using the Petrov-like boundary condition in near horizon limit, we study the correspondence between gravitational perturbation and fluid equation. We find that the dual fluid equation for rotating black holes contains a Coriolis force term, which is closely related to the angular velocity of the black hole horizon. This can be seen as a dual effect for the frame-dragging effect of rotating black hole under the holographic picture.
Rotating Black Holes and Coriolis Effect
Xiaoning Wu; Yi Yang; Pei-Hung Yuan; Chia-Jui Cho
2015-11-27
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.
Port hole perturbations to the magnetic field in MST
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access|Post-Polymerization Modifications - EnergyPolyether-Polyol-2 (2010)
Core Holes | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, Alabama (Utility Company)| Open(Evans,Oregon: EnergyInformationOpen1988)|Holes Jump
Advanced MHD models of anisotropy, flow and chaotic fields
Hudson, Stuart
Advanced MHD models of anisotropy, flow and chaotic fields M. J. Hole1, M. Fitzgerald1, G. Dennis1, pressure" #12;Expected impact of anisotropy · If p > p||, an increase will occur in centrifugal shift : [R
Sotani, Hajime
2015-01-01
We systematically examine the properties of null geodesics around an electrically charged, asymptotically flat black hole in Eddington-inspired Born-Infeld gravity, varying the electric charge of black hole and the coupling constant in the theory. We find that the radius of the unstable circular orbit for massless particle decreases with the coupling constant, if the value of the electrical charge is fixed. Additionally, we consider the strong gravitational lensing around such a black hole. We show that the deflection angle, the position angle of the relativistic images, and the magnification due to the light bending in strong gravitational field are quite sensitive to the parameters determining the black hole solution. Thus, through the accurate observations associated with the strong gravitational lensing, it might be possible to reveal the gravitational theory in a strong field regime.
Dyer, Bill
and demand in the U.S., with only part of the demand being met by U.S. production. Canola oil has achieved1 1 June 2011 A-1280 Canola Production Field Guide Canola Production Field Guide 2 2 Edited.....................................101 · Contributors to Canola Production Field Guide........102 · Resource Contact Information
The scattering matrix approach for the quantum black hole, an overview
G. 't Hooft
1996-07-09
If one assumes the validity of conventional quantum field theory in the vicinity of the horizon of a black hole, one does not find a quantum mechanical description of the entire black hole that even remotely resembles that of conventional forms of matter; in contrast with matter made out of ordinary particles one finds that, even if embedded in a finite volume, a black hole would be predicted to have a strictly continuous spectrum. Dissatisfied with such a result, which indeed hinges on assumptions concerning the horizon that may well be wrong, various investigators have now tried to formulate alternative approaches to the problem of ``quantizing" the black hole. We here review the approach based on the assumption of quantum mechanical purity and unitarity as a starting point, as has been advocated by the present author for some time, concentrating on the physics of the states that should live on a black hole horizon. The approach is shown to be powerful in not only producing promising models for the quantum black hole, but also new insights concerning the dynamics of physical degrees of freedom in ordinary flat space-time.
Can black holes and naked singularities be detected in accelerators?
R. Casadio; B. Harms
2002-01-07
We study the conditions for the existence of black holes that can be produced in colliders at TeV-scale if the space-time is higher dimensional. On employing the microcanonical picture, we find that their life-times strongly depend on the details of the model. If the extra dimensions are compact (ADD model), microcanonical deviations from thermality are in general significant near the fundamental TeV mass and tiny black holes decay more slowly than predicted by the canonical expression, but still fast enough to disappear almost instantaneously. However, with one warped extra dimension (RS model), microcanonical corrections are much larger and tiny black holes appear to be (meta)stable. Further, if the total charge is not zero, we argue that naked singularities do not occur provided the electromagnetic field is strictly confined on an infinitely thin brane. However, they might be produced in colliders if the effective thickness of the brane is of the order of the fundamental length scale (~1/TeV).
Supersymmetric black holes and attractors in gauged supergravity with hypermultiplets
Samuele Chimento; Dietmar Klemm; Nicolò Petri
2015-04-13
We consider four-dimensional $N=2$ supergravity coupled to vector- and hypermultiplets, where abelian isometries of the quaternionic K\\"ahler hypermultiplet scalar manifold are gauged. Using the recipe given by Meessen and Ort\\'{\\i}n in arXiv:1204.0493, we analytically construct a supersymmetric black hole solution for the case of just one vector multiplet with prepotential ${\\cal F}=-i\\chi^0\\chi^1$, and the universal hypermultiplet. This solution has a running dilaton, and it interpolates between $\\text{AdS}_2\\times\\text{H}^2$ at the horizon and a hyperscaling-violating type geometry at infinity, conformal to $\\text{AdS}_2\\times\\text{H}^2$. It carries two magnetic charges that are completely fixed in terms of the parameters that appear in the Killing vector used for the gauging. In the second part of the paper, we extend the work of Bellucci et al. on black hole attractors in gauged supergravity to the case where also hypermultiplets are present. The attractors are shown to be governed by an effective potential $V_{\\text{eff}}$, which is extremized on the horizon by all the scalar fields of the theory. Moreover, the entropy is given by the critical value of $V_{\\text{eff}}$. In the limit of vanishing scalar potential, $V_{\\text{eff}}$ reduces (up to a prefactor) to the usual black hole potential.
$P-V$ criticality of AdS black hole in the Einstein-Maxwell-power-Yang-Mills gravity
Ming Zhang; Zhan-Ying Yang; De-Cheng Zou; Wei Xu; Rui-Hong Yue
2014-12-03
We study the $P-V$ critical behaivor of N-dimensional AdS black holes in Einstein-Maxwell-power-Yang-Mills gravity. Our results show the existence of the Van der Waals like small-large black hole phase transitions when taking some special values of charges of the Maxwell and Yang-Mills (YM) fields. Further to calculate the critical exponents of the black holes at the critical point, we find that they are the same as those in the Van der Waals liquid-gas system.
Class Transitions in Black Holes
Sandip K. Chakrabarti
2005-01-14
A black hole spectrum is known to change from the hard state to the soft state when the energy spectral index $\\alpha$ ($F_E \\propto E^{-\\alpha}$) in, say, 2-20 keV range changes from $\\alpha \\sim 0.5$ to $\\sim 1.5$. However, this `classical' definition which characterizes black holes like Cyg X-1, becomes less useful for many objects such as GRS 1915+105 in which the spectral slope is seen to vary from one to the other in a matter of seconds and depending on whether or not winds form, the spectral slope also changes. The light curves and the colour-colour diagrams may look completely different on different days depending on the frequency and mode of switching from one spectral state to the other. Though RXTE observations have yielded wealth of information on such `variability classes' in GRS 1915+105, very rarely one has been able to observe how the object goes from one class to the other. In the present review, we discuss possible origins of the class transition and present several examples of such transitions. In this context, we use mostly the results of the Indian X-ray Astronomy Experiment (IXAE) which observed GRS 1915+105 more regularly.
Mandel, Ilya
2005-10-15
The most promising way to compute the gravitational waves emitted by binary black holes (BBHs) in their last dozen orbits, where post-Newtonian techniques fail, is a quasistationary approximation introduced by Detweiler and being pursued by Price and others. In this approximation the outgoing gravitational waves at infinity and downgoing gravitational waves at the holes' horizons are replaced by standing waves so as to guarantee that the spacetime has a helical Killing vector field. Because the horizon generators will not, in general, be tidally locked to the holes' orbital motion, the standing waves will destroy the horizons, converting the black holes into naked singularities that resemble black holes down to near the horizon radius. This paper uses a spherically symmetric, scalar-field model problem to explore in detail the following BBH issues: (i) The destruction of a horizon by the standing waves. (ii) The accuracy with which the resulting naked singularity resembles a black hole. (iii) The conversion of the standing-wave spacetime (with a destroyed horizon) into a spacetime with downgoing waves by the addition of a 'radiation-reaction field'. (iv) The accuracy with which the resulting downgoing waves agree with the downgoing waves of a true black-hole spacetime (with horizon). The model problem used to study these issues consists of a Schwarzschild black hole endowed with spherical standing waves of a scalar field, whose wave frequency and near-horizon energy density are chosen to match those of the standing gravitational waves of the BBH quasistationary approximation. It is found that the spacetime metric of the singular, standing-wave spacetime, and its radiation-reaction-field-constructed downgoing waves are quite close to those for a Schwarzschild black hole with downgoing waves--sufficiently close to make the BBH quasistationary approximation look promising for non-tidally-locked black holes.
Quantum Entropy of Charged Rotating Black Holes
R. B. Mann
1996-07-10
I discuss a method for obtaining the one-loop quantum corrections to the tree-level entropy for a charged Kerr black hole. Divergences which appear can be removed by renormalization of couplings in the tree-level gravitational action in a manner similar to that for a static black hole.
Topological Black Holes in Quantum Gravity
J. Kowalski-Glikman; D. Nowak-Szczepaniak
2000-07-31
We derive the black hole solutions with horizons of non-trivial topology and investigate their properties in the framework of an approach to quantum gravity being an extension of Bohm's formulation of quantum mechanics. The solutions we found tend asymptotically (for large $r$) to topological black holes. We also analyze the thermodynamics of these space-times.
Primordial black holes and asteroid danger
Alexander Shatskiy
2008-02-21
Probability for a primordial black hole to invade the Kuiper belt was calculated. We showed that primordial black holes of certain masses can significantly change asteroids' orbits. These events may result in disasters, local for our solar system and global for the Earth (like the Tunguska meteorite). We also estimated how often such events occur.
Canonical structure of 2D black holes
Navarro-Salas, J; Talavera, C F
1994-01-01
We determine the canonical structure of two-dimensional black-hole solutions arising in $2D$ dilaton gravity. By choosing the Cauchy surface appropriately we find that the canonically conjugate variable to the black hole mass is given by the difference of local (Schwarzschild) time translations at right and left spatial infinities. This can be regarded as a generalization of Birkhoff's theorem.
Fractal Statistics and Quantum Black Hole Entropy
Wellington da Cruz
2000-11-18
Simple considerations about the fractal characteristic of the quantum-mechanical path give us the opportunity to derive the quantum black hole entropy in connection with the concept of fractal statistics. We show the geometrical origin of the numerical factor of four of the quantum black hole entropy expression and the statistics weight appears as a counting of the quanta of geometry.
Thermal Gradient Holes At Northern Basin & Range Region (Pritchett...
Thermal Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes...
Slim Holes At Blue Mountain Geothermal Area (Fairbank Engineering...
Slim Holes At Blue Mountain Geothermal Area (Fairbank Engineering Ltd, 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Slim Holes At Blue...
Effective theories and black hole production in warped compactificatio...
Office of Scientific and Technical Information (OSTI)
Effective theories and black hole production in warped compactifications Citation Details In-Document Search Title: Effective theories and black hole production in warped...
Thermal Gradient Holes At Upper Hot Creek Ranch Area (Benoit...
gradient holes up to 500' deep were initially planned but higher than anticipated drilling and permitting costs within a fixed budget reduced the number of holes to five....
Brookhaven National Laboratory - Sr90 - Chemical Holes | Department...
Office of Environmental Management (EM)
- Chemical Holes Brookhaven National Laboratory - Sr90 - Chemical Holes January 1, 2014 - 12:00pm Addthis US Department of Energy Groundwater Database Groundwater Master Report...
Lake, Matthew J
2015-01-01
The discovery of a large number of supermassive black holes at redshifts $z> 6$, when the Universe was only nine hundred million years old, has raised the fundamental question of how such massive compact objects could form in a (cosmologically) short time interval. Each of the proposed standard scenarios for black hole formation, involving rapid accretion of seed black holes, or black hole mergers, faces severe theoretical difficulties in explaining the short time formation of supermassive objects. In the present Letter, we propose an alternative scenario for the formation of supermassive black holes in the early Universe in which energy transfer from superconducting cosmic strings, piercing small seed black holes, is the main physical process leading to rapid mass increase. The increase in mass of a primordial seed black hole pierced by two antipodal strings is estimated and it is shown that this increases linearly in time. Due to the high energy transfer rate from the cosmic strings, we find that supermassi...
Method of determining interwell oil field fluid saturation distribution
Donaldson, Erle C. (Bartlesville, OK); Sutterfield, F. Dexter (Bartlesville, OK)
1981-01-01
A method of determining the oil and brine saturation distribution in an oil field by taking electrical current and potential measurements among a plurality of open-hole wells geometrically distributed throughout the oil field. Poisson's equation is utilized to develop fluid saturation distributions from the electrical current and potential measurement. Both signal generating equipment and chemical means are used to develop current flow among the several open-hole wells.
Higher spin black hole entropy in three dimensions
Alfredo Perez; David Tempo; Ricardo Troncoso
2013-09-05
A generic formula for the entropy of three-dimensional black holes endowed with a spin-3 field is found, which depends on the horizon area A and its spin-3 analogue, given by the reparametrization invariant integral of the induced spin-3 field at the spacelike section of the horizon. From this result it can be shown that the absolute value of the spin-3 analogue of the area has to be bounded from above by A/3^(1/2). The entropy formula is constructed by requiring the first law of thermodynamics to be fulfilled in terms of the global charges obtained through the canonical formalism. For the static case, in the weak spin-3 field limit, our expression for the entropy reduces to the result found by Campoleoni, Fredenhagen, Pfenninger and Theisen, which has been recently obtained through a different approach.
Nonthermal correction to black hole spectroscopy
Wen-Yu Wen
2014-11-14
Area spectrum of black holes have 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 negative specific heat and therefore tend to stay away from thermal equilibrium. Even for those black holes with positive specific heat, temperature may still not be well defined in the process of radiation, due to the back reaction of decreasing mass. 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.
Evidence for the Black Hole Event Horizon
Ramesh Narayan
2003-10-23
Astronomers have discovered many candidate black holes in X-ray binaries and in the nuclei of galaxies. The candidate objects are too massive to be neutron stars, and for this reason they are considered to be black holes. While the evidence based on mass is certainly strong, there is no proof yet that any of the objects possesses the defining characteristic of a black hole, namely an event horizon. Type I X-ray bursts, which are the result of thermonuclear explosions when gas accretes onto the surface of a compact star, may provide important evidence in this regard. Type I bursts are commonly observed in accreting neutron stars, which have surfaces, but have never been seen in accreting black hole candidates. It is argued that the lack of bursts in black hole candidates is compelling evidence that these objects do not have surfaces. The objects must therefore possess event horizons.
How fast can a black hole rotate?
Herdeiro, Carlos A R
2015-01-01
Kerr black holes have their angular momentum, $J$, bounded by their mass, $M$: $Jc\\leqslant GM^2$. There are, however, known black hole solutions violating this Kerr bound. We propose a very simple universal bound on the rotation, rather than on the angular momentum, of four-dimensional, stationary and axisymmetric, asymptotically flat black holes, given in terms of an appropriately defined horizon linear velocity, $v_H$. The $v_H$ bound is simply that $v_H$ cannot exceed the velocity of light. We verify the $v_H$ bound for known black hole solutions, including some that violate the Kerr bound, and conjecture that only extremal Kerr black holes saturate the $v_H$ bound.
Landau-Lifshitz and Weinberg Energy-Momentum Complexes for 2+1 Dimensional Black Hole Solutions
I. Radinschi; I-Ching Yang
2007-02-19
The aim of this paper is to evaluate the energy distribution of some 2+1 black hole solutions applying the Landau-Lifshitz and Weinberg definitions. The metrics under consideration describe the charged black hole, the solution coupling to a static scalar field and the static and circularly symmetric exact solution of the Einstein-massless scalar equation. Further, we compare the expressions for energy with those obtained using the Einstein and Moller prescriptions and give a discussion of the results.
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Static Frame
Peng Wang; Haitang Yang
2015-05-12
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appears that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study possible deviations from the Hawking's prediction, the dispersive field theory models have been proposed, following the Unruh's hydrodynamic analogue of a black hole radiation. In the dispersive field theory models, the dispersion relations of matter fields are modified at high energies, which leads to modifications of equations of motion. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass $m_{p}$. We calculate the corrections to the Hawking temperature for massive and charged particles to $\\mathcal{O}\\left(m_{p}^{-2}\\right) $ and massless and neutral particles to all orders. Our results suggest that the thermal spectrum of radiations near horizon is robust, e.g. corrections to the Hawking temperature are suppressed by $m_{p}$. After the spectrum of radiations near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole. We find that the leading term of the entropy depends on how the dispersion relations of matter fields are modified, while the subleading logarithmic term does not. Finally, the luminosities of black holes are computed by using the geometric optics approximation.
Jets from Tidal Disruptions of Stars by Black Holes
Julian H. Krolik; Tsvi Piran
2012-02-07
Tidal disruption of main sequence stars by black holes has generally been thought to lead to a signal dominated by UV emission. If, however, the black hole spins rapidly and the poloidal magnetic field intensity on the black hole horizon is comparable to the inner accretion disk pressure, a powerful jet may form whose luminosity can easily exceed the thermal UV luminosity. When the jet beam points at Earth, its non-thermal luminosity can dominate the emitted spectrum. The thermal and non-thermal components decay differently with time. In particular, the thermal emission should remain roughly constant for a significant time after the period of maximum accretion, beginning to diminish only after a delay, whereas after the peak accretion rate, the non-thermal jet emission decays, but then reaches a plateau. Both transitions are tied to a characteristic timescale $t_{\\rm Edd}$ at which the accretion rate falls below Eddington. Making use of this timescale in a new parameter-inference formalism for tidal disruption events with significant emission from a jet, we analyze the recent flare source Swift J2058. It is consistent with an event in which a main sequence solar-type staris disrupted by a black hole of mass $\\sim 4 \\times 10^7 M_{\\odot}$. The beginning of the flat phase in the non-thermal emission from this source can possibly be seen in the late-time lightcurve. Optical photometry over the first $\\simeq 40$ d of this flare is also consistent with this picture, but is only weakly constraining because the bolometric correction is very uncertain. We suggest that future searches for main sequence tidal disruptions use methods sensitive to jet radiation as well as to thermal UV radiation.
Interacting spins and holes in zigzag edge nanographene
Dutta, Sudipta; Wakabayashi, Katsunori
2013-12-04
We have investigated charge and spin gap properties of zigzag edge graphene nanoribbons (ZGNRs) modeled within Hubbard Hamiltonian with onsite electron-electron interaction using semi-empirical many-body configuration interaction (CI) method. The charge gap behavior resembles the mean-field results, showing minima near Dirac point. We have observed unprecedented gap-less spin excitations over the flat band region. Moreover, doping the ZGNRs with holes reduces both the charge and spin gaps, inducing metallic and magnetic behavior, which can be exploited to fabricate spintronic devices.
Black hole temperature: Minimal coupling vs conformal coupling
Fazel, Mohamadreza; Mirza, Behrouz; Mansoori, Seyed Ali Hosseini
2014-05-15
In this article, we discuss the propagation of scalar fields in conformally transformed spacetimes with either minimal or conformal coupling. The conformally coupled equation of motion is transformed into a one-dimensional Schrödinger-like equation with an invariant potential under conformal transformation. In a second stage, we argue that calculations based on conformal coupling yield the same Hawking temperature as those based on minimal coupling. Finally, it is conjectured that the quasi normal modes of black holes are invariant under conformal transformation.
Ultrafast Core-Hole Induced Dynamics in Water
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafast Core-Hole Induced Dynamics
Ultrafast Core-Hole Induced Dynamics in Water
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafast Core-Hole Induced
Ultrafast Core-Hole Induced Dynamics in Water
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafast Core-Hole InducedUltrafast
Two Electron Holes in Hematite Facilitate Water Splitting
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPP UPDATE: April 15, 2014Two Electron Holes in Hematite
Two Electron Holes in Hematite Facilitate Water Splitting
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPP UPDATE: April 15, 2014Two Electron Holes in HematiteTwo
Two Electron Holes in Hematite Facilitate Water Splitting
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPP UPDATE: April 15, 2014Two Electron Holes in HematiteTwoTwo
Two Electron Holes in Hematite Facilitate Water Splitting
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPP UPDATE: April 15, 2014Two Electron Holes in
Two Electron Holes in Hematite Facilitate Water Splitting
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPP UPDATE: April 15, 2014Two Electron Holes inTwo Electron
Generalised Smarr Formula and the Viscosity Bound for Einstein-Maxwell-Dilaton Black Holes
Liu, Hai-Shan; Pope, C N
2015-01-01
We study the shear viscosity to entropy ratio $\\eta/S$ in the boundary field theories dual to black hole backgrounds in theories of gravity coupled to a scalar field, and generalisations including a Maxwell field and non-minimal scalar couplings. Motivated by the observation in simple examples that the saturation of the $\\eta/S\\ge 1/(4\\pi)$ bound is correlated with the existence of a generalised Smarr relation for the planar black-hole solutions, we investigate this in detail for the general black-hole solutions in these theories, focusing especially on the cases where the scalar field plays a non-trivial role and gives rise to an additional parameter in the space of solutions. We find that a generalised Smarr relation holds in all cases, and in fact it can be viewed as the bulk gravity dual of the statement of the saturation of the viscosity to entropy bound. We obtain the generalised Smarr relation, whose existence depends upon a scaling symmetry of the planar black-hole solutions, by two different but rela...
Solar cycle changes in coronal holes and space weather cycles J. G. Luhmann,1
California at Berkeley, University of
Solar cycle changes in coronal holes and space weather cycles J. G. Luhmann,1 Y. Li,1 C. N. Arge,2-heliolatitude solar wind over approximately the last three solar cycles. Related key parameters like interplanetary explain solar magnetic field control of long-term interplanetary variations. In particular, the enduring
Radion clouds around evaporating black holes
J. R. Morris
2009-09-03
A Kaluza-Klein model, with a matter source associated with Hawking radiation from an evaporating black hole, is used to obtain a simple form for the radion effective potential. The environmental effect generally causes a matter-induced shift of the radion vacuum, resulting in the formation of a radion cloud around the hole. There is an albedo due to the radion cloud, with an energy dependent reflection coefficient that depends upon the size of the extra dimensions and the temperature of the hole.
Quasinormal Modes of Dirty Black Holes
P. T. Leung; Y. T. Liu; W. -M. Suen; C. Y. Tam; K. Young
1999-03-08
Quasinormal mode (QNM) gravitational radiation from black holes is expected to be observed in a few years. A perturbative formula is derived for the shifts in both the real and the imaginary part of the QNM frequencies away from those of an idealized isolated black hole. The formulation provides a tool for understanding how the astrophysical environment surrounding a black hole, e.g., a massive accretion disk, affects the QNM spectrum of gravitational waves. We show, in a simple model, that the perturbed QNM spectrum can have interesting features.
Shaghoulian, Edgar
2015-01-01
We extend a recently derived higher-dimensional Cardy formula to include angular momenta, which we use to obtain the Bekensten-Hawking entropy of AdS black branes, compactified rotating branes, and large Schwarzschild/Kerr black holes. This is the natural generalization of Strominger's microscopic derivation of the BTZ black hole entropy to higher dimensions. We propose an extension to include $U(1)$ charge, which agrees with the Bekenstein-Hawking entropy of large Reissner-Nordstrom/Kerr-Newman black holes at high temperature. We extend the results to arbitrary hyperscaling violation exponent (this captures the case of black D$p$-branes as a subclass) and reproduce logarithmic corrections.
Some remarks on black hole thermodynamics
R. Y. Chiao
2011-02-04
Two thermodynamic "paradoxes" of black hole physics are re-examined. The first is that there is a thermal instability involving two coupled blackbody cavities containing two black holes, and second is that a classical black hole can swallow up entropy in the form of ambient blackbody photons without increasing its mass. The resolution of the second paradox by Bekenstein and by Hawking is re-visited. The link between Hawking radiation and Wigner's superluminal tunneling time is discussed using two equivalent Feynman diagrams, and Feynman's re-interpretation principle.
Thermodynamics of Dyonic Lifshitz Black Holes
Tobias Zingg
2011-07-15
Black holes with asymptotic anisotropic scaling are conjectured to be gravity duals of condensed matter system close to quantum critical points with non-trivial dynamical exponent z at finite temperature. A holographic renormalization procedure is presented that allows thermodynamic potentials to be defined for objects with both electric and magnetic charge in such a way that standard thermodynamic relations hold. Black holes in asymptotic Lifshitz spacetimes can exhibit paramagnetic behavior at low temperature limit for certain values of the critical exponent z, whereas the behavior of AdS black holes is always diamagnetic.
Scalar Perturbations of Charged Dilaton Black Holes
Sharmanthie Fernando; Keith Arnold
2015-08-01
We have studied the scalar perturbation of static charged dilaton black holes in 3+1 dimensions. The black hole considered here is a solution to the low-energy string theory in 3+1 dimensions. The quasinormal modes for the scalar perturbations are calculated using the third order WKB method. The dilaton coupling constant has a considerable effect on the values of quasi normal modes. It is also observed that there is a linear relation between the quasi normal modes and the temperature for large black holes.
Black Holes with Scalar Hairs in Einstein-Gauss-Bonnet Gravity
Y. Brihaye; L. Ducobu
2015-11-21
The Einstein-Gauss-Bonnet gravity in five dimensions is extended by scalar fields and the corresponding equations are reduced to a system of non-linear differential equations. A large family of regular solutions of these equations is shown to exist. Generically, these solutions are spinning black holes with scalar hairs. They can be characterized (but not uniquely) by an horizon and an angular velocity on this horizon. Taking particular limits the black holes approach boson star or become extremal, in any case the limiting configurations remain hairy.
Black Holes with Scalar Hairs in Einstein-Gauss-Bonnet Gravity
Brihaye, Y
2015-01-01
The Einstein-Gauss-Bonnet gravity in five dimensions is extended by scalar fields and the corresponding equations are reduced to a system of non-linear differential equations. A large family of regular solutions of these equations is shown to exist. Generically, these solutions are spinning black holes with scalar hairs. They can be characterized (but not uniquely) by an horizon and an angular velocity on this horizon. Taking particular limits the black holes approach boson star or become extremal, in any case the limiting configurations remain hairy.
Hypersymmetry bounds and three-dimensional higher-spin black holes
Marc Henneaux; Alfredo Perez; David Tempo; Ricardo Troncoso
2015-06-05
We investigate the hypersymmetry bounds on the higher spin black hole parameters that follow from the asymptotic symmetry superalgebra in higher-spin anti-de Sitter gravity in three spacetime dimensions. We consider anti-de Sitter hypergravity for which the analysis is most transparent. This is a $osp(1\\vert 4) \\oplus osp(1\\vert 4)$ Chern-Simons theory which contains, besides a spin-$2$ field, a spin-$4$ field and a spin-$5/2$ field. The asymptotic symmetry superalgebra is then the direct sum of two-copies of the hypersymmetric extension $W_{(2,\\frac52,4)}$ of $W_{(2,4)}$, which contains fermionic generators of conformal weight $5/2$ and bosonic generators of conformal weight $4$ in addition to the Virasoro generators. Following standard methods, we derive bounds on the conserved charges from the anticommutator of the hypersymmetry generators. The hypersymmetry bounds are nonlinear and are saturated by the hypersymmetric black holes, which turn out to possess $1/4$-hypersymmetry and to be "extreme", where extremality can be defined in terms of the entropy: extreme black holes are those that fulfill the extremality bounds beyond which the entropy ceases to be a real function of the black hole parameters. We also extend the analysis to other $sp(4)$-solitonic solutions which are maximally (hyper)symmetric.
Bright Transients from Black Hole - Neutron Star Mergers
D'Orazio, Daniel J; Murray, Norman W; Price, Larry
2016-01-01
Direct detection of black hole-neutron star (BHNS) pairs is anticipated with the advent of aLIGO. Electromagnetic counterparts may be crucial for a confident gravitational-wave detection as well as for extraction of astronomical information. Yet BHNS star pairs are notoriously dark and so inaccessible to telescopes. Contrary to this expectation, a bright electromagnetic transient can occur in the final moments before merger as long as the neutron star is highly magnetized. The orbital motion of the neutron star magnet creates a Faraday flux and corresponding power available for luminosity. A spectrum of curvature radiation ramps up until the rapid injection of energy ignites a fireball, which would appear as an energetic blackbody peaking in the X-ray to gamma-rays for neutron star field strengths ranging from $10^{12}$G to $10^{16}$G respectively and a $10M_{\\odot}$ black hole. The fireball event may last from a few milliseconds to a few seconds depending on the NS magnetic field strength, and may be observa...
A 5x10^9 Solar Mass Black Hole in NGC 1277 from Adaptive Optics Spectroscopy
Walsh, Jonelle L; Gebhardt, Karl; Y?ld?r?m, Ak?n; Richstone, Douglas O; Gültekin, Kayhan; Husemann, Bernd
2015-01-01
The nearby lenticular galaxy NGC 1277 is thought to host one of the largest black holes known, however the black hole mass measurement is based on low spatial resolution spectroscopy. In this paper, we present Gemini Near-infrared Integral Field Spectrometer observations assisted by adaptive optics. We map out the galaxy's stellar kinematics within ~440 pc of the nucleus with an angular resolution that allows us to probe well within the region where the potential from the black hole dominates. We find that the stellar velocity dispersion rises dramatically, reaching ~550 km/s at the center. Through orbit-based, stellar-dynamical models we obtain a black hole mass of (4.9 \\pm 1.6) x 10^9 Msun (1-sigma uncertainties). Although the black hole mass measurement is smaller by a factor of ~3 compared to previous claims based on large-scale kinematics, NGC 1277 does indeed contain one of the most massive black holes detected to date, and the black hole mass is an order of magnitude larger than expectations from the e...
Energy of 4-Dimensional Black Hole, etc
Dmitriy Palatnik
2011-07-18
In this letter I suggest possible redefinition of mass density, not depending on speed of the mass element, which leads to a more simple stress-energy for an object. I calculate energy of black hole.
Horizon Operator Approach to Black Hole Quantization
G. 't Hooft
1994-02-21
The $S$-matrix Ansatz for the construction of a quantum theory of black holes is further exploited. We first note that treating the metric tensor $g_{\\m\
Radiation transport around Kerr black holes
Schnittman, Jeremy David
2005-01-01
This Thesis describes the basic framework of a relativistic ray-tracing code for analyzing accretion processes around Kerr black holes. We begin in Chapter 1 with a brief historical summary of the major advances in black ...
Time-bin entangled photon holes
J. Liang; J. D. Franson; T. B. Pittman
2012-08-23
The general concept of entangled photon holes is based on a correlated absence of photon pairs in an otherwise constant optical background. Here we consider the specialized case when this background is confined to two well-defined time bins, which allows the formation of time-bin entangled photon holes. We show that when the typical coherent state background is replaced by a true single-photon (Fock state) background, the basic time-bin entangled photon-hole state becomes equivalent to one of the time-bin entangled photon-pair states. We experimentally demonstrate these ideas using a parametric down-conversion photon-pair source, linear optics, and post-selection to violate a Bell inequality with time-bin entangled photon holes.
Evidence for the Black Hole Event Horizon
Ramesh Narayan; Jeremy S. Heyl
2002-04-26
Roughly a dozen X-ray binaries are presently known in which the compact accreting primary stars are too massive to be neutron stars. These primaries are identified as black holes, though there is as yet no definite proof that any of the candidate black holes actually possesses an event horizon. We discuss how Type I X-ray bursts may be used to verify the presence of the event horizon in these objects. Type I bursts are caused by thermonuclear explosions when gas accretes onto a compact star. The bursts are commonly seen in many neutron star X-ray binaries, but they have never been seen in any black hole X-ray binary. Our model calculations indicate that black hole candidates ought to burst frequently if they have surfaces. Based on this, we argue that the lack of bursts constitutes strong evidence for the presence of event horizons in these objects.
Black Hole Thermodynamics in Modified Gravity
Jonas R. Mureika; John W. Moffat; Mir Faizal
2015-03-03
We analyze the thermodynamics of a non-rotating and rotating black hole in a modified theory of gravity that includes scalar and vector modifications to general relativity, which results in a modified gravitational constant $G = G_N(1+\\alpha)$ and a new gravitational charge $Q = \\sqrt{\\alpha G_N}M$. The influence of the parameter $\\alpha$ alters the non-rotating black hole's lifetime, temperature and entropy profiles from the standard Schwarzschild case. The thermodynamics of a rotating black hole is analyzed and it is shown to possess stable, cold remnants. The thermodynamic properties of a vacuum solution regular at $r=0$ are investigated and the solution without a horizon called a "gray hole" is not expected to possess an information loss problem.
CHARYBDIS: A Black hole event generator.
Harris, Chris M.; Richardson, P.; Webber, Bryan R.
CHARYBDIS is an event generator which simulates the production and decay of miniature black holes at hadronic colliders as might be possible in certain extra dimension models. It interfaces via the Les Houches accord to general purpose Monte...
Thermodynamics and evaporation of the noncommutative black hole
Yun Soo Myung; Yong-Wan Kim; Young-Jai Park
2007-01-21
We investigate the thermodynamics of the noncommutative black hole whose static picture is similar to that of the nonsingular black hole known as the de Sitter-Schwarzschild black hole. It turns out that the final remnant of extremal black hole is a thermodynamically stable object. We describe the evaporation process of this black hole by using the noncommutativity-corrected Vaidya metric. It is found that there exists a close relationship between thermodynamic approach and evaporation process.
Black Holes and Thunderbolt Singularities with Lifshitz Scaling Terms
Misonoh, Yosuke
2015-01-01
We study a static, spherically symmetric and asymptotic flat spacetime, assuming the hypersurface orthogonal Einstein-aether theory with an ultraviolet modification motivated by the Horava-Lifshitz theory, which is composed of the $z=2$ Lifshitz scaling terms such as scalar combinations of a three-Ricci curvature and the acceleration of the aether field. For the case with the quartic term of the acceleration of the aether field, we obtain a two-parameter family of black hole solutions, which possess a regular universal horizon. While, if three-Ricci curvature squared term is joined in ultraviolet modification, we find a solution with a thunderbolt singularity such that the universal horizon turns to be a spacelike singularity.
Gödel black hole, closed timelike horizon, and the study of particle emissions
Sourav Bhattacharya; Anirban Saha
2010-07-22
We show that a particle, with positive orbital angular momentum, following an outgoing null/timelike geodesic, shall never reach the closed timelike horizon (CTH) present in the $(4+1)$-dimensional rotating G\\"{o}del black hole space-time. Therefore a large part of this space-time remains inaccessible to a large class of geodesic observers, depending on the conserved quantities associated with them. We discuss how this fact and the existence of the closed timelike curves present in the asymptotic region make the quantum field theoretic study of the Hawking radiation, where the asymptotic observer states are a pre-requisite, unclear. However, the semiclassical approach provides an alternative to verify the Smarr formula derived recently for the rotating G\\"{o}del black hole. We present a systematic analysis of particle emissions, specifically for scalars, charged Dirac spinors and vectors, from this black hole via the semiclassical complex path method.
The different phases of hairy black holes in AdS5 space
Gaston Giribet; Andres Goya; Julio Oliva
2014-12-31
We investigate the thermodynamics of hairy black holes in asymptotically Anti-de Sitter (AdS) space, including backreaction. Resorting to the Euclidean path integral approach, we show that matter conformally coupled to Einstein gravity in five dimensions may exhibit a phase transition whose endpoint turns out to be a hairy black hole in AdS5 space. The scalar field configuration happens to be regular everywhere outside and on the horizon, and behaves asymptotically in such a way that respects the AdS boundary conditions that are relevant for AdS/CFT. The theory presents other peculiar features in the ultraviolet, like the existence of black holes with arbitrarily low temperature in AdS5. This provides a simple setup in which the fully backreacting problem of a hair forming in AdS at certain critical temperature can be solved analytically.
The different phases of hairy black holes in AdS5 space
Giribet, Gaston; Oliva, Julio
2015-01-01
We investigate the thermodynamics of hairy black holes in asymptotically Anti-de Sitter (AdS) space, including backreaction. Resorting to the Euclidean path integral approach, we show that matter conformally coupled to Einstein gravity in five dimensions may exhibit a phase transition whose endpoint turns out to be a hairy black hole in AdS5 space. The scalar field configuration happens to be regular everywhere outside and on the horizon, and behaves asymptotically in such a way that respects the AdS boundary conditions that are relevant for AdS/CFT. The theory presents other peculiar features in the ultraviolet, like the existence of black holes with arbitrarily low temperature in AdS5. This provides a simple setup in which the fully backreacting problem of a hair forming in AdS at certain critical temperature can be solved analytically.
Classical and thermodynamic stability of black holes
Monteiro, Ricardo
2010-07-06
Perturbations of the asymptotic charges . . . . . . . . . . . . . . . . 169 IV Conclusion 171 9 Conclusion and outlook 173 A Spectral numerical method 177 2 CONTENTS Part I Introduction 3 Chapter 1 Black holes Black holes are arguably the most interesting... to Newto- nian dynamics in the Solar system, and the indirect detection of gravitational waves from binary pulsars [1]. A crucial distinction from Newtonian gravity is that the “action-at-a-distance” is substituted by a built-in causality structure...
Fractionated Branes and Black Hole Interiors
Emil J. Martinec
2015-05-20
Combining a variety of results in string theory and general relativity, a picture of the black hole interior is developed wherein spacetime caps off at an inner horizon, and the inter-horizon region is occupied by a Hagedorn gas of a very low tension state of fractionated branes. This picture leads to natural resolutions of a variety of puzzles concerning quantum black holes. Gravity Research Foundation 2015 Fourth Prize Award for Essays on Gravitation.
Symmetry and the arrow of time in theoretical black hole astrophysics
David Garofalo
2015-07-27
While the basic laws of physics seem time-reversal invariant, our understanding of the apparent irreversibility of the macroscopic world is well grounded in the notion of entropy. Because astrophysics deals with the largest structures in the Universe, one expects evidence there for the most pronounced entropic arrow of time. However, in recent theoretical astrophysics work it appears possible to identify constructs with time-reversal symmetry, which is puzzling in the large-scale realm especially because it involves the engines of powerful outflows in active galactic nuclei which deal with macroscopic constituents such as accretion disks, magnetic fields, and black holes. Nonetheless, the underlying theoretical structure from which this accreting black hole framework emerges displays a time-symmetric harmonic behavior, a feature reminiscent of basic and simple laws of physics. While we may expect such behavior for classical black holes due to their simplicity, manifestations of such symmetry on the scale of galaxies, instead, surprise. In fact, we identify a parallel between the astrophysical tug-of-war between accretion disks and jets in this model and the time symmetry-breaking of a simple overdamped harmonic oscillator. The validity of these theoretical ideas in combination with this unexpected parallel suggests that black holes are more influential in astrophysics than currently recognized and that black hole astrophysics is a more fundamental discipline.
Kerr black holes and time profiles of gamma-ray bursts
S. McBreen; B. McBreen; L. Hanlon; F. Quilligan
2002-08-19
The cumulative light curves of gamma-ray bursts (GRBs) smooth the spiky nature of the running light curve. The cumulative count increases in an approximately linear way with time t for most bursts. In 19 out of 398 GRBs with T90 > 2s, the cumulative light curve was found to increase with time as \\~t^2 implying a linear increase in the running light curve. The non-linear sections last for a substantial fraction of the GRB duration, have a large proportion of the cumulative count and many resolved pulses that usually end with the highest pulse in the burst. The reverse behaviour was found in 11 GRBs where the running light curve decreased with time and some bursts are good mirror images of the increases. These GRBs are among the spectrally hardest bursts observed by BATSE. The most likely interpretation is that these effects are signatures of black holes that are either being spun up or down in the accretion process. In the spin up case, the increasing Kerr parameter of the black hole allows additional rotational and accretion energy to become available for extraction. The process is reversed if the black hole is spun down by magnetic field torques. The luminosity changes in GRBs are consistent with the predictions of the BZ process and neutrino annihilation and thus provide the link to spinning black holes. GRBs provide a new window for studying the general relativistic effects of Kerr black holes.
Jin Li; Kai Lin; Nan Yang
2015-03-24
Based on a regular exact black hole (BH) from nonlinear electrodynamics (NED) coupled to General Relativity, we investigate its stability of such BH through the Quasinormal Modes (QNMs) of electromagnetic (EM) field perturbation and its thermodynamics through Hawking radiation. In perturbation theory, we can deduce the effective potential from nonlinear EM field. The comparison of potential function between regular and RN BHs could predict their similar QNMs. The QNMs frequencies tell us the effect of magnetic charge $q$, overtone $n$, angular momentum number $l$ on the dynamic evolution of NLED EM field. Furthermore we also discuss the cases near extreme condition of such magnetically charged regular BH. The corresponding QNMs spectrum illuminates some special properties in the near-extreme cases. For the thermodynamics, we employ Hamilton-Jacobi method to calculate the near-horizon Hawking temperature of the regular BH and reveal the relationship between classical parameters of black hole and its quantum effect.
Quantum modes around a scalar-tensor black hole: breakdown of the normalization conditions
F. G. Alvarenga; A. B. Batista; J. C. Fabris; G. T. Marques
2004-04-12
Black holes arising in the context of scalar-tensor gravity theories, where the scalar field is non-minimally coupled to the curvature term, have zero surface gravity. Hence, it is generally stated that their Hawking temperature is zero, irrespectivelly of their gravitational and scalar charges. The proper analysis of the Hawking temperature requires to study the propagation of quantum fields in the space-time determined by these objects. We study scalar fields in the vicinity of the horizon of these black holes. It is shown that the scalar modes do not form an orthonormal set. Hence, the Hilbert space is ill-definite in this case, and no notion of temperature can be extracted for such objects.
Brick Walls for Black Holes in AdS/CFT
Norihiro Iizuka; Seiji Terashima
2015-01-01
We study the 't Hooft's brick wall model for black holes in a holographic context. The brick wall model suggests that without an appropriate near horizon IR cut-off, the free energy of the probe fields show the divergence due to the large degenerate states near the horizons. After studying the universal nature of the divergence in various holographic setting in various dimensions, we interpret the nature of the divergence in a holographic context. The free energy divergence is due to the large degeneracy and continuity of the low energy spectrum in the boundary theory at the deconfinement phase. These divergence and continuity should be removed by finite N effects, which make the spectrum discrete even at the deconfinement phase. On the other hand, in the bulk, these degenerate states are localized near the horizon, and the universal divergence of these degenerate states implies that the naive counting of the degrees of freedom in bulk should be modified once we take into account the non-perturbative quantum gravity effects near the horizon. Depending on the microscopic degrees of freedom, the position, where the effective field theory description to count the states breaks down, has different Planck scale dependence. It also implies the difficulty to have an electron like gauge-singlet elementary field in the boundary theory Lagrangian. These singlet fields are at most composite fields, because they show divergent free energy, suggesting a positive power of N at the deconfinement phase.
Improving hole injection efficiency by manipulating the hole transport mechanism through
Demir, Hilmi Volkan
-emitting diodes (LEDs) for elec- tron overflow suppression. However, a typical EBL also reduces the hole injection to be the key to enhancing the hole injection efficiency. InGaN/ GaN LEDs with the proposed p-type AlGaN/GaN/AlGaN EBL have demonstrated substantially higher optical output power and external quantum efficiency
Rotating black hole thermodynamics with a particle probe
Gwak, Bogeun; Lee, Bum-Hoon
2011-10-15
The thermodynamics of Myers-Perry black holes in general dimensions are studied using a particle probe. When undergoing particle absorption, the changes of the entropy and irreducible mass are shown to be dependent on the particle radial momentum. The black hole thermodynamic behaviors are dependent on dimensionality for specific rotations. For a 4-dimensional Kerr black hole, its black hole properties are maintained for any particle absorption. 5-dimensional black holes can avoid a naked ring singularity by absorbing a particle in specific momenta ranges. Black holes over 6 dimensions become ultraspinning black holes through a specific form of particle absorption. The microscopical changes are interpreted in limited cases of Myers-Perry black holes using Kerr/CFT correspondence. We systematically describe the black hole properties changed by particle absorption in all dimensions.
The Revival of White Holes as Small Bangs
Alon Retter; Shlomo Heller
2011-07-17
Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact time reversal of black holes, therefore they should continuously throw away material. It is accepted, however, that a persistent ejection of mass leads to gravitational pressure, the formation of a black hole and thus to the "death of while holes". So far, no astronomical source has been successfully tagged a white hole. The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting. We thus suggest that the emergence of a white hole, which we name a 'Small Bang', is spontaneous - all the matter is ejected at a single pulse. Unlike black holes, white holes cannot be continuously observed rather their effect can only be detected around the event itself. Gamma ray bursts are the most energetic explosions in the universe. Long gamma-ray bursts were connected with supernova eruptions. There is a new group of gamma-ray bursts, which are relatively close to Earth, but surprisingly lack any supernova emission. We propose identifying these bursts with white holes. White holes seem like the best explanation of gamma-ray bursts that appear in voids. We also predict the detection of rare gigantic gamma-ray bursts with energies much higher than typically observed.
K. S. Virbhadra; C. R. Keeton
2007-10-11
We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for the Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due the Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, the strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image on the same side as the source) due to strongly naked singularity lensing always has negative time delay. We also found that the scalar field decreases the time delay and increases the magnitude of magnifications of images; this result could have important implications for cosmology. As the Janis-Newman-Winicour metric also describes the exterior gravitational field of a scalar star, naked singularities as well as scalar star lenses, if these exist in nature, will serve as more efficient cosmic telescopes than regular gravitational lenses.
Virbhadra, K. S.; Keeton, C. R.
2008-06-15
We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due to Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image on the same side as the source) due to strongly naked singularity lensing always has a negative time delay. We also found that the scalar field decreases the time delay and increases the total magnification of images; this result could have important implications for cosmology. As the Janis-Newman-Winicour metric also describes the exterior gravitational field of a scalar star, naked singularities as well as scalar star lenses, if these exist in nature, will serve as more efficient cosmic telescopes than regular gravitational lenses.
of the harmonic power spectrum of the solar magnetic field demonstrates a greater prevalence of multiLOW-LATITUDE CORONAL HOLES AT THE MINIMUM OF THE 23rd SOLAR CYCLE This article has been downloaded reserved. Printed in the U.S.A. LOW-LATITUDE CORONAL HOLES AT THE MINIMUM OF THE 23rd SOLAR CYCLE Valentyna
Holographic superconductor in the exact hairy black hole
Yun Soo Myung; Chanyong Park
2011-09-13
We study the charged black hole of hyperbolic horizon with scalar hair (charged Martinez-Troncoso-Zanelli: CMTZ black hole) as a model of analytic hairy black hole for holographic superconductor. For this purpose, we investigate the second order phase transition between CMTZ and hyperbolic Reissner-Nordstr\\"om-AdS (HRNAdS) black holes. However, this transition unlikely occur. As an analytic treatment for holographic superconductor, we develop superconductor in the bulk and superfluidity on the boundary using the CMTZ black hole below the critical temperature. The presence of charge destroys the condensates around the zero temperature, which is in accord with the thermodynamic analysis of the CMTZ black hole.
Naked Singularity formation in scalar field collapse
Rituparno Goswami; Pankaj S Joshi
2004-10-28
We construct here a class of collapsing scalar field models with a non-zero potential, which result in a naked singularity as collapse end state. The weak energy condition is satisfied by the collapsing configuration. It is shown that physically it is the rate of collapse that governs either the black hole or naked singularity formation as the final state for the dynamical evolution. It is seen that the cosmic censorship is violated in dynamical scalar field collapse.
BLACK HOLE FORAGING: FEEDBACK DRIVES FEEDING
Dehnen, Walter; King, Andrew, E-mail: wd11@leicester.ac.uk, E-mail: ark@astro.le.ac.uk [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)] [Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH (United Kingdom)
2013-11-10
We suggest a new picture of supermassive black hole (SMBH) growth in galaxy centers. Momentum-driven feedback from an accreting hole gives significant orbital energy, but little angular momentum to the surrounding gas. Once central accretion drops, the feedback weakens and swept-up gas falls back toward the SMBH on near-parabolic orbits. These intersect near the black hole with partially opposed specific angular momenta, causing further infall and ultimately the formation of a small-scale accretion disk. The feeding rates into the disk typically exceed Eddington by factors of a few, growing the hole on the Salpeter timescale and stimulating further feedback. Natural consequences of this picture include (1) the formation and maintenance of a roughly toroidal distribution of obscuring matter near the hole; (2) random orientations of successive accretion disk episodes; (3) the possibility of rapid SMBH growth; (4) tidal disruption of stars and close binaries formed from infalling gas, resulting in visible flares and ejection of hypervelocity stars; (5) super-solar abundances of the matter accreting on to the SMBH; and (6) a lower central dark-matter density, and hence annihilation signal, than adiabatic SMBH growth implies. We also suggest a simple subgrid recipe for implementing this process in numerical simulations.
Perturbative String Thermodynamics near Black Hole Horizons
Thomas G. Mertens; Henri Verschelde; Valentin I. Zakharov
2015-07-01
We provide further computations and ideas to the problem of near-Hagedorn string thermodynamics near (uncharged) black hole horizons, building upon our earlier work JHEP 1403 (2014) 086. The relevance of long strings to one-loop black hole thermodynamics is emphasized. We then provide an argument in favor of the absence of $\\alpha'$-corrections for the (quadratic) heterotic thermal scalar action in Rindler space. We also compute the large $k$ limit of the cigar orbifold partition functions (for both bosonic and type II superstrings) which allows a better comparison between the flat cones and the cigar cones. A discussion is made on the general McClain-Roth-O'Brien-Tan theorem and on the fact that different torus embeddings lead to different aspects of string thermodynamics. The black hole/string correspondence principle for the 2d black hole is discussed in terms of the thermal scalar. Finally, we present an argument to deal with arbitrary higher genus partition functions, suggesting the breakdown of string perturbation theory (in $g_s$) to compute thermodynamical quantities in black hole spacetimes.
Black Hole Spin in AGN and GBHCs
Christopher S. Reynolds; Laura W. Brenneman; David Garofalo
2004-10-05
We discuss constraints on black hole spin and spin-related astrophysics as derived from X-ray spectroscopy. After a brief discussion about the robustness with which X-ray spectroscopy can be used to probe strong gravity, we summarize how these techniques can constrain black hole spin. In particular, we highlight XMM-Newton studies of the Seyfert galaxy MCG-6-30-15 and the stellar-mass black hole GX339-4. The broad X-ray iron line profile, together with reasonable and general astrophysical assumptions, allow a non-rotating black hole to be rejected in both of these sources. If we make the stronger assertion of no emission from within the innermost stable circular orbit, the MCG-6-30-15 data constrain the dimensionless spin parameter to be a>0.93. Furthermore, these XMM-Newton data are already providing evidence for exotic spin-related astrophysics in the central regions of this object. We conclude with a discussion of the impact that Constellation-X will have on the study of strong gravity and black hole spin.
Investigating Dark Energy with Black Hole Binaries
Laura Mersini-Houghton; Adam Kelleher
2009-06-08
The accelerated expansion of the universe is ascribed to the existence of dark energy. Black holes accretion of dark energy induces a mass change proportional to the energy density and pressure of the background dark energy fluid. The time scale during which the mass of black holes changes considerably is too long relative to the age of the universe, thus beyond detection possibilities. We propose to take advantage of the modified black hole masses for exploring the equation of state $w[z]$ of dark energy, by investigating the evolution of supermassive black hole binaries on a dark energy background. Deriving the signatures of dark energy accretion on the evolution of binaries, we find that dark energy imprints on the emitted gravitational radiation and on the changes in the orbital radius of the binary can be within detection limits for certain supermassive black hole binaries. In this talk I describe how binaries can provide a useful tool in obtaining complementary information on the nature of dark energy, based on the work done with A.Kelleher.
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Static Frame
Wang, Peng
2015-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appears that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study possible deviations from the Hawking's prediction, the dispersive field theory models have been proposed, following the Unruh's hydrodynamic analogue of a black hole radiation. In the dispersive field theory models, the dispersion relations of matter fields are modified at high energies, which leads to modifications of equations of motion. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the static frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energies but is modified near the Planck mass $m_{p}$. We calculate the corrections to the Hawking temperature for massive and charged particles to $\\mathcal{O}\\left(m_{p}^{-2}\\right) $ and massless and neutral particles to all orders. Our res...
Universality of critical magnetic field in holographic superconductor
D. Momeni; R. Myrzakulov
2015-02-11
In this letter we study aspects of the holographic superconductors analytically in the presence of a constant external magnetic field. We show that the critical temperature and critical magnetic field can be calculated at nonzero temperature. We detect the Meissner effect in such superconductors. A universal relation between black hole mass $ M$ and critical magnetic field $H_c$ is proposed as $\\frac{H_c}{M^{2/3}}\\leq 0.687365$. We discuss some aspects of phase transition in terms of black hole entropy and the Bekenstein's entropy to energy upper bound.
Mesolensing Explorations of Nearby Masses: From Planets to Black Holes
R. Di Stefano
2007-12-20
Nearby masses can have a high probability of lensing stars in a distant background field. High-probability lensing, or mesolensing, can therefore be used to dramatically increase our knowledge of dark and dim objects in the solar neighborhood, where it can discover and study members of the local dark population (free-floating planets, low-mass dwarfs, white dwarfs, neutron stars, and stellar mass black holes). We can measure the mass and transverse velocity of those objects discovered (or already known), and determine whether or not they are in binaries with dim companions. We explore these and other applications of mesolensing, including the study of forms of matter that have been hypothesized but not discovered, such as intermediate-mass black holes, dark matter objects free-streaming through the Galactic disk, and planets in the outermost regions of the solar system. In each case we discuss the feasibility of deriving results based on present-day monitoring systems, and also consider the vistas that will open with the advent of all-sky monitoring in the era of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), and the Large Synoptic Survey Telescope (LSST).
Ultrahard fluid and scalar field in the Kerr-Newman metric
Babichev, E.; Chernov, S.; Dokuchaev, V.; Eroshenko, Yu.
2008-11-15
An analytic solution for the accretion of ultrahard perfect fluid onto a moving Kerr-Newman black hole is found. This solution is a generalization of the previously known solution by Petrich, Shapiro, and Teukolsky for a Kerr black hole. We show that the found solution is applicable for the case of a nonextreme black hole, however it cannot describe the accretion onto an extreme black hole due to violation of the test fluid approximation. We also present a stationary solution for a massless scalar field in the metric of a Kerr-Newman naked singularity.
Fast Radio Bursts and Radio Transients from Black Hole Batteries
Chiara M. F. Mingarelli; Janna Levin; T. Joseph W. Lazio
2015-11-09
Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS--BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is $20\\%-80\\%$ as luminous, given 0.5~ms timing resolution. The main burst is from the peak luminosity before merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS--BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with electromagnetic counterparts greatly augmenting the scientific leverage beyond the GW signal. Valuably, the electromagnetic signal can break degeneracies in the parameters encoded in the GW as well as probe the NS magnetic field strength, yielding insights into open problems in NS magnetic field decay.
Primordial Black Holes Formation from Particle Production during Inflation
Erfani, Encieh
2015-01-01
We study the possibility that particle production during inflation can source the required power spectrum for dark matter (DM) primordial black holes (PBH) formation. We consider the scalar and the gauge quanta production in inflation models, where in the latter case, we focus in two sectors: inflaton coupled i) directly and ii) gravitationally to a $U(1)$ gauge field. We do not assume any specific potential for the inflaton field. Hence, in the gauge production case, in a model independent way we show that the non-production of DM PBHs puts stronger upper bound on the particle production parameter. Our analysis show that this bound is more stringent than the bounds from the bispectrum and the tensor-to-scalar ratio derived by gauge production in these models. In the scenario where the inflaton field coupled to a scalar field, we put an upper bound on the amplitude of the generated scalar power spectrum by non-production of PBHs. As a by-product we also show that the required scalar power spectrum for PBHs fo...
Neutrino Majorana Mass from Black Hole
Yosuke Uehara
2002-05-25
We propose a new mechanism to generate the neutrino Majorana mass in TeV-scale gravity models. The black hole violates all non-gauged symmetries and can become the origin of lepton number violating processes. The fluctuation of higher-dimensional spacetime can result in the production of a black hole, which emits 2 neutrinos. If neutrinos are Majorana particles, this process is equivalent to the free propagation of a neutrino with the insertion of the black hole. From this fact, we derive the neutrino Majorana mass. The result is completely consistent with the recently observed evidence of neutrinoless double beta decay. And the obtained neutrino Majorana mass satisfies the constraint from the density of the neutrino dark matter, which affects the cosmic structure formation. Furthermore, we can explain the ultrahigh energy cosmic rays by the Z-burst scenario with it.
No Supermassive Black Hole in M33?
David Merritt; Laura Ferrarese; Charles L. Joseph
2001-07-20
We analyze optical long-slit spectroscopy of the nucleus of M33 obtained from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Rather than the steep rise expected within the radius of influence of a supermassive black hole, the velocity dispersion drops significantly within the inner parsec. Dynamical modelling yields an estimated upper limit of 3000 solar masses for the mass of a central compact object. This upper limit is however consistent within the uncertainties with the mass predicted by the M-sigma relation, which is between 2000 and 20,000 solar masses. We therefore can not conclude that the presence of a massive black hole in the nucleus of M33 would require a different formation mechanism from that of the black holes detected in galaxies with more luminous bulges.
DIVERSION OF ADULT SALMON BY AN ELECTRICAL FIELD
DIVERSION OF ADULT SALMON BY AN ELECTRICAL FIELD Marine Biological Laboratory : -1958 WOODS HOLE OF ADULT SALMON BY AN ELECTRICAL FIELD By Roger E. Burrows Fishery Research Biologist Entiat, Wash. Bureau 1957 #12;ABSTRACT An electrical weir consisting of a line of hanging electrodes and a submerged ground
Edwin Barnes; Diana Vaman; Chaolun Wu
2009-10-26
We derive the dual CFT Virasoro algebras from the algebra of conserved diffeomorphism charges, for a large class of abelian Kaluza-Klein black holes. Under certain conditions, such as non-vanishing electric and magnetic monopole charges, the Kaluza-Klein black holes have a Reissner-Nordstrom space-time structure. For the non-extremal charged Kaluza-Klein black holes, we use the uplifted 6d pure gravity solutions to construct a set of Killing horizon preserving diffeomorphisms. For the (non-supersymmetric) extremal black holes, we take the NENH limit, and construct a one-parameter family of diffeomorphisms which preserve the Hamiltonian constraints at spatial infinity. In each case we evaluate the algebra of conserved diffeomorphism charges following Barnich, Brandt and Compere, who used a cohomological approach, and Silva, who employed a covariant-Lagrangian formalism. At the Killing horizon, it is only Silva's algebra which acquires a central charge extension, and which enables us to recover the Bekenstein-Hawking black hole entropy from the Cardy formula. For the NENH geometry, the extremal black hole entropy is obtained only when the free parameter of the diffeomorphism generating vector fields is chosen such that the central terms of the two algebras are in agreement.
CHARYBDIS: A Black Hole Event Generator
C. M. Harris; P. Richardson; B. R. Webber
2003-07-29
CHARYBDIS is an event generator which simulates the production and decay of miniature black holes at hadronic colliders as might be possible in certain extra dimension models. It interfaces via the Les Houches accord to general purpose Monte Carlo programs like HERWIG and PYTHIA which then perform the parton evolution and hadronization. The event generator includes the extra-dimensional `grey-body' effects as well as the change in the temperature of the black hole as the decay progresses. Various options for modelling the Planck-scale terminal decay are provided.
Virtual Black Holes in Hyperbolic Metamaterials
Igor I. Smolyaninov
2011-01-24
Optical space in electromagnetic metamaterials may be engineered to emulate various exotic space-time geometries. However, these metamaterial models are limited in many respects. It is believed that real physical space-time strongly fluctuates on the Planck scale. These fluctuations are usually described as virtual black holes. Static metamaterial models introduced so far do not exhibit similar behavior. Here we demonstrate that thermal fluctuations of optical space in hyperbolic metamaterials lead to creation of virtual electromagnetic black holes. This effect is very large if the dielectric component of the metamaterial exhibits critical opalescence.
Thermal Gravitational Waves from Primordial Black Holes
C. Sivaram; Kenath Arun
2010-05-19
Thermal gravitational waves can be generated in various sources such as, in the cores of stars, white dwarfs and neutron stars due to the fermion collisions in the dense degenerate Fermi gas. Such high frequency thermal gravitational waves can also be produced during the collisions in a gamma ray burst or during the final stages of the evaporation of primordial black holes. Here we estimate the thermal gravitational waves from primordial black holes and estimate the integrated energy of the gravitational wave emission over the entire volume of the universe and over Hubble time. We also estimate the gravitational wave flux from gamma ray bursts and jets.
Thermal stability of radiant black holes
Parthasarathi Majumdar
2006-04-06
Beginning with a brief sketch of the derivation of Hawking's theorem of horizon area increase, based on the Raychaudhuri equation, we go on to discuss the issue as to whether generic black holes, undergoing Hawking radiation, can ever remain in stable thermal equilibrium with that radiation. We derive a universal criterion for such a stability, which relates the black hole mass and microcanonical entropy, both of which are well-defined within the context of the Isolated Horizon, and in principle calculable within Loop Quantum Gravity. The criterion is argued to hold even when thermal fluctuations of electric charge are considered, within a {\\it grand} canonical ensemble.
Black Hole Thermodynamics and Statistical Mechanics
Steven Carlip
2008-07-28
We have known for more than thirty years that black holes behave as thermodynamic systems, radiating as black bodies with characteristic temperatures and entropies. This behavior is not only interesting in its own right; it could also, through a statistical mechanical description, cast light on some of the deep problems of quantizing gravity. In these lectures, I review what we currently know about black hole thermodynamics and statistical mechanics, suggest a rather speculative "universal" characterization of the underlying states, and describe some key open questions.
Dynamics of galaxy cores and supermassive black holes
David Merritt
2006-05-02
Recent work on the dynamical evolution of galactic nuclei containing supermassive black holes is reviewed. Topics include galaxy structural properties; collisionless and collisional equilibria; loss-cone dynamics; and dynamics of binary and multiple supermassive black holes.
Evolution of Accretion Discs around a Kerr Black Hole using Extended Magnetohydrodynamics
Foucart, Francois; Gammie, Charles F; Quataert, Eliot
2015-01-01
Black holes accreting well below the Eddington rate are believed to have geometrically thick, optically thin, rotationally supported accretion discs in which the Coulomb mean free path is large compared to $GM/c^2$. In such an environment, the disc evolution may differ significantly from ideal magnetohydrodynamic predictions. We present non-ideal global axisymmetric simulations of geometrically thick discs around a rotating black hole. The simulations are carried out using a new code ${\\rm\\it grim}$, which evolves a covariant extended magnetohydrodynamics model derived by treating non-ideal effects as a perturbation of ideal magnetohydrodynamics. Non-ideal effects are modeled through heat conduction along magnetic field lines, and a difference between the pressure parallel and perpendicular to the field lines. The model relies on an effective collisionality in the disc from wave-particle scattering and velocity-space (mirror and firehose) instabilities. We find that the pressure anisotropy grows to match the ...
Graphene and the Zermelo Optical Metric of the BTZ Black Hole
M. Cvetic; G. W. Gibbons
2012-05-23
It is well known that the low energy electron excitations of the curved graphene sheet $\\Sigma$ are solutions of the massless Dirac equation on a 2+1 dimensional ultra-static metric on ${\\Bbb R} \\times \\Sigma$. An externally applied electric field on the graphene sheet induces a gauge potential which could be mimicked by considering a stationary optical metric of the Zermelo form, which is conformal to the BTZ black hole when the sheet has a constant negative curvature. The Randers form of the metric can model a magnetic field, which is related by a boost to an electric one in the Zermelo frame. We also show that there is fundamental geometric obstacle to obtaining a model that extends all the way to the black hole horizon.
Entropy and Area of Black Holes in Loop Quantum Gravity
I. B. Khriplovich
2002-03-31
Simple arguments related to the entropy of black holes strongly constrain the spectrum of the area operator for a Schwarzschild black hole in loop quantum gravity. In particular, this spectrum is fixed completely by the assumption that the black hole entropy is maximum. Within the approach discussed, one arrives in loop quantum gravity at a quantization rule with integer quantum numbers $n$ for the entropy and area of a black hole.
SEARCH FOR SUPERMASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL...
Office of Scientific and Technical Information (OSTI)
ASTROPHYSICS; BLACK HOLES; COMPARATIVE EVALUATIONS; CORRELATIONS; COSMOLOGY; GALAXIES; GALAXY NUCLEI; NONLUMINOUS MATTER; OSCILLATIONS; QUASARS; VELOCITY Word Cloud More Like This...
Black holes: interfacing the classical and the quantum
B. P. Kosyakov
2007-07-18
The central idea advocated in this paper is that {forming the black hole horizon is attended with transition from the classical regime of evolution to the quantum one}. We justify the following criterion for discriminating between the classical and the quantum: {spontaneous creations and annihilations of particle-antiparticle pairs are impossible in the classical world but possible in the quantum world}. We show that it is sufficient to {change the overall sign of the spacetime signature in the classical picture of field propagation for it to be treated as its associated quantum picture}. To describe a self-gravitating object at the last stage of its classical evolution, we propose to use the Foldy--Wouthuysen representation of the Dirac equation in curved spacetimes, and the Gozzi classical path integral. In both approaches, maintaining the dynamics in the classical regime is controlled by supersymmetry.
Null trajectories and bending of light in charged black holes with quintessence
Sharmanthie Fernando; Scott Meadows; Kevon Reis
2015-06-15
We have studied null geodesics of the charged black hole surrounded by quintessence. Quintessence is a candidate for dark energy and is represented by a scalar field. Here, we have done a detailed study of the photon trajectories. The exact solutions for the trajectories are obtained in terms of the Jacobi-elliptic integrals for all possible energy and angular momentum of the photons. We have also studied the bending angle using the Rindler and Ishak method.
Yves Decanini; Antoine Folacci; Mohamed Ould El Hadj
2015-06-30
With in mind the possibility to test massive gravity in the context of black hole physics, we consider the radiation produced by a particle plunging from slightly below the innermost stable circular orbit into a Schwarzschild black hole. In order to circumvent the difficulties associated with black hole perturbation theory in massive gravity, we use a toy model where we replace the graviton field by a massive scalar field and consider a linear coupling between the particle and this field. We compute the waveform generated by the plunging particle and study its spectral content. This permits us to highlight and interpret some important effects occurring in the plunge regime which are not present for massless fields such as (i) the decreasing and vanishing, as the mass parameter increases, of the signal amplitude generated when the particle moves on quasicircular orbits near the innermost stable circular orbit and (ii) in addition to the excitation of the quasinormal modes, the excitation of the quasibound states of the black hole.
MOTION OF ELECTRON-HOLE DROPS IN Ge
Westervelt, R.M.
2011-01-01
MOTION OF ELECTRON-HOLE DROPS IN Ge R. M. Westervelt, J. C.MOTION OF ELECTRON-HOLE DROPS IN Ge R. M. Westervelt, J. C.OF ELECTRON-HOLE DROPS IN Ge R M Westervelt, J C Culbertson
ANCHIALINE ECOSYSTEMS Microbial hotspots in anchialine blue holes
Macalady, Jenn
ANCHIALINE ECOSYSTEMS Microbial hotspots in anchialine blue holes: initial discoveries from+Business Media B.V. 2011 Abstract Inland blue holes of the Bahamas are anchialine ecosystems with distinct fresh and geomicrobiology exploration of blue holes are providing a first glimpse of the geochemistry and microbial life
Light in tiny holes & T. W. Ebbesen1
Turro, Nicholas J.
REVIEWS Light in tiny holes C. Genet1 & T. W. Ebbesen1 The presence of tiny holes in an opaque metal film, with sizes smaller than the wavelength of incident light, leads to a wide variety of unexpected optical properties such as strongly enhanced transmission of light through the holes
The Role of Primordial Kicks on Black Hole Merger Rates
Miroslav Micic; Tom Abel; Steinn Sigurdsson
2006-09-06
Primordial stars are likely to be very massive $\\geq30\\Msun$, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos in the mass range $10^{6}-10^{10}\\Ms$. Such early black holes, at redshifts z$\\gtsim10$, could be the seed black holes for the many supermassive black holes found in galaxies in the local universe. If they exist, their mergers with nearby supermassive black holes may be a prime signal for long wavelength gravitational wave detectors. We simulate formation of black holes in the center of high redshift dark matter halos and explore implications of initial natal kick velocities conjectured by some formation models. The central concentration of early black holes in present day galaxies is reduced if they are born even with moderate kicks of tens of km/s. The modest kicks allow the black holes to leave their parent halo, which consequently leads to dynamical friction being less effective on the lower mass black holes as compared to those still embedded in their parent halos. Therefore, merger rates may be reduced by more than an order of magnitude. Using analytical and illustrative cosmological N--body simulations we quantify the role of natal kicks of black holes formed from massive metal free stars on their merger rates with supermassive black holes in present day galaxies. Our results also apply to black holes ejected by the gravitational slingshot mechanism.
Charged fermions tunneling from accelerating and rotating black holes
Rehman, Mudassar; Saifullah, K., E-mail: mudassir051@yahoo.com, E-mail: saifullah@qau.edu.pk [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan)
2011-03-01
We study Hawking radiation of charged fermions from accelerating and rotating black holes with electric and magnetic charges. We calculate the tunneling probabilities of incoming and outgoing fermionic particles and find the Hawking temperature of these black holes. We also provide an explicit expression of the classical action for the massive and massless particles in the background of these black holes.
Electric field induced spin-polarized current
Murakami, Shuichi; Nagaosa, Naoto; Zhang, Shoucheng
2006-05-02
A device and a method for generating an electric-field-induced spin current are disclosed. A highly spin-polarized electric current is generated using a semiconductor structure and an applied electric field across the semiconductor structure. The semiconductor structure can be a hole-doped semiconductor having finite or zero bandgap or an undoped semiconductor of zero bandgap. In one embodiment, a device for injecting spin-polarized current into a current output terminal includes a semiconductor structure including first and second electrodes, along a first axis, receiving an applied electric field and a third electrode, along a direction perpendicular to the first axis, providing the spin-polarized current. The semiconductor structure includes a semiconductor material whose spin orbit coupling energy is greater than room temperature (300 Kelvin) times the Boltzmann constant. In one embodiment, the semiconductor structure is a hole-doped semiconductor structure, such as a p-type GaAs semiconductor layer.
Global Warming Hole 31 March 2015
Hansen, James E.
Global Warming Hole 31 March 2015 James Hansen Sorry to have disappeared for two months. I-thirds of North America know that global warming is really happening. In fact, 2015 should be the year that stifles discussion of a warming hiatus. A substantial developing El Nino will add to the global warming
Flip-flopping binary black holes
Carlos O. Lousto; James Healy
2015-03-14
We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of $d\\approx25M$ between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for $t=20000M$ and displays a total change in the orientation of the spin of one of the black holes from initially aligned with the orbital angular momentum to a complete anti-alignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 Post-Newtonian equations of motion and spin evolution to show that this process continuously flip-flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes.
Scalar Hairy Black Holes in General Dimensions
Xing-Hui Feng; H. Lu; Qiang Wen
2014-01-13
We obtain a class of asymptotic flat or (A)dS hairy black holes in D-dimensional Einstein gravity coupled to a scalar with certain scalar potential. For a given mass, the theory admits both the Schwarzschild-Tangherlini and the hairy black holes with different temperature and entropy, but satisfying the same first law of thermodynamics. For some appropriate choice of parameters, the scalar potential can be expressed in terms of a super-potential and it can arise in gauged supergravities. In this case, the solutions develop a naked curvature singularity and become the spherical domain walls. Uplifting the solutions to D=11 or 10, we obtain solutions that can be viewed as spherical M-branes or D3-branes. We also add electric charges to these hairy black holes. All these solutions contain no scalar charges in that the first law of thermodynamics are unmodified. We also try to construct new AdS black holes carrying scalar charges, with some moderate success in that the charges are pre-fixed in the theory instead of being some continuous integration constants.
Scalar Hairy Black Holes in General Dimensions
Feng, Xing-Hui; Wen, Qiang
2013-01-01
We obtain a class of asymptotic flat or (A)dS hairy black holes in D-dimensional Einstein gravity coupled to a scalar with certain scalar potential. For a given mass, the theory admits both the Schwarzschild-Tangherlini and the hairy black holes with different temperature and entropy, but satisfying the same first law of thermodynamics. For some appropriate choice of parameters, the scalar potential can be expressed in terms of a super-potential and it can arise in gauged supergravities. In this case, the solutions develop a naked curvature singularity and become the spherical domain walls. Uplifting the solutions to D=11 or 10, we obtain solutions that can be viewed as spherical M-branes or D3-branes. We also add electric charges to these hairy black holes. All these solutions contain no scalar charges in that the first law of thermodynamics are unmodified. We also try to construct new AdS black holes carrying scalar charges, with some moderate success in that the charges are pre-fixed in the theory instead ...
Remote down-hole well telemetry
Briles, Scott D. (Los Alamos, NM); Neagley, Daniel L. (Albuquerque, NM); Coates, Don M. (Santa Fe, NM); Freund, Samuel M. (Los Alamos, NM)
2004-07-20
The present invention includes an apparatus and method for telemetry communication with oil-well monitoring and recording instruments located in the vicinity of the bottom of gas or oil recovery pipes. Such instruments are currently monitored using electrical cabling that is inserted into the pipes; cabling has a short life in this environment, and requires periodic replacement with the concomitant, costly shutdown of the well. Modulated reflectance, a wireless communication method that does not require signal transmission power from the telemetry package will provide a long-lived and reliable way to monitor down-hole conditions. Normal wireless technology is not practical since batteries and capacitors have to frequently be replaced or recharged, again with the well being removed from service. RF energy generated above ground can also be received, converted and stored down-hole without the use of wires, for actuating down-hole valves, as one example. Although modulated reflectance reduces or eliminates the loss of energy at the sensor package because energy is not consumed, during the transmission process, additional stored extra energy down-hole is needed.
Lower-Dimensional Black Hole Chemistry
Antonia M. Frassino; Robert B. Mann; Jonas R. Mureika
2015-09-18
The connection between black hole thermodynamics and chemistry is extended to the lower-dimensional regime by considering the rotating and charged BTZ metric in the $(2+1)$-D and a $(1+1)$-D limits of Einstein gravity. The Smarr relation is naturally upheld in both BTZ cases, where those with $Q \
Area products for black hole horizons
Visser, Matt
2013-01-01
Area products for multi-horizon black holes often have intriguing properties, and are often independent of the mass of the black hole (depending only on various charges, angular momenta, and moduli). Such products are often formulated in terms of the areas of inner (Cauchy) horizons and event horizons, and often include the effects of unphysical "virtual'" horizons. For the Schwarzschild-de Sitter [Kottler] black hole in (3+1) dimensions it is shown by explicit exact calculation that the product of event horizon area and cosmological horizon area is not mass independent. (Including the effect of the third "virtual" horizon does not improve the situation.) Similarly, in the Reissner-Nordstrom-anti-de Sitter black hole in (3+1) dimensions the product of inner (Cauchy) horizon area and event horizon area is calculated (perturbatively), and is shown to be not mass independent. That is, the mass-independence of the product of physical horizon areas is not generic. In the generic situation, whenever the quasi-local...
Marek Rogatko
1998-07-09
Using the ADM formulation of the Einstein-Maxwell axion-dilaton gravity we derived the formulas for the variation of mass and other asymptotic conserved quantities in the theory under consideration. Generalizing this kind of reasoning to the initial dota for the manifold with an interior boundary we got the generalized first law of black hole mechanics. We consider an asymptotically flat solution to the Einstein-Maxwell axion-dilaton gravity describing a black hole with a Killing vector field timelike at infinity, the horizon of which comprises a bifurcate Killing horizon with a bifurcate surface. Supposing that the Killing vector field is asymptotically orthogonal to the static hypersurface with boundary S and compact interior, we find that the solution is static in the exterior world, when the timelike vector field is normal to the horizon and has vanishing electric and axion- electric fields on static slices.
Entropy of near-extremal black holes in AdS5
Simon, Joan; Balasubramanian, Vijay; de Boer, Jan; Jejjala, Vishnu; Simon, Joan
2007-07-24
We construct the microstates of near-extremal black holes in AdS_5 x S5 as gases of defects distributed in heavy BPS operators in the dual SU(N) Yang-Mills theory. These defects describe open strings on spherical D3-branes in the S5, and we show that they dominate the entropy by directly enumerating them and comparing the results with a partition sum calculation. We display new decoupling limits in which the field theory of the lightest open strings on the D-branes becomes dual to a near-horizon region of the black hole geometry. In the single-charge black hole we find evidence for an infrared duality between SU(N) Yang-Mills theories that exchanges the rank of the gauge group with an R-charge. In the two-charge case (where pairs of branes intersect on a line), the decoupled geometry includes an AdS_3 factor with a two-dimensional CFT dual. The degeneracy in this CFT accounts for the black hole entropy. In the three-charge case (where triples of branes intersect at a point), the decoupled geometry contains an AdS_2 factor. Below a certain critical mass, the two-charge system displays solutions with naked timelike singularities even though they do not violate a BPS bound. We suggest a string theoretic resolution of these singularities.
Sarica, C.; Demir, H.M.; Brill, J.P.
1996-09-01
Weep holes have been used widely to detect the presence of Liquefied Petroleum Gases (LPG) in brine for underground compensated storage systems. When the brine level drops below the weep hole, LPG product enters the brine production system causing an increase in both tubing head pressure and flow rate. To prevent cavern overfill, a cavern shutdown is initiated upon detection of LPG in the surface brine system by pressure or flow instruments at the tubing head. In this study, we have investigated the multiphase flow characteristics of weep hole LPG detection systems to correctly estimate the operating limits. A simple and easy to use model has been developed to predict the tubing head pressure and flow rate increases. The model can be used to implement safer and more efficient operation procedures for underground compensated LPG storage systems. The model predictions for a typical field case are presented. An analysis of weep holes as product detection devices for LPG storage reservoirs has been carried out. It was found that the increases in pressure and flow rates at the tubing head change as a function of injection flow rate of the product. Therefore, a thorough consideration of cavern operating parameters is necessary to evaluate the use constant pressure and flow rate values to initiate emergency shut down of the cavern.
Trumpet-puncture initial data for black holes
Immerman, Jason D.; Baumgarte, Thomas W.
2009-09-15
We propose a new approach, based on the puncture method, to construct black hole initial data in the so-called trumpet geometry, i.e. on slices that asymptote to a limiting surface of nonzero areal radius. Our approach is easy to implement numerically and, at least for nonspinning black holes, does not require any internal boundary conditions. We present numerical results, obtained with a uniform-grid finite-difference code, for boosted black holes and binary black holes. We also comment on generalizations of this method for spinning black holes.
Cormac Breen; Adrian C. Ottewill
2012-01-11
We consider a quantum field which is in a Hartle-Hawking state propagating in a general spherically symmetric black hole space-time. We make use of uniform approximations to the radial equation to calculate the components of the stress tensor, renormalized using the Hadamard form of the Green's function, on the horizons of this space-time. We then specialize these results to the case of the `lukewarm' Reissner-Nordstrom-de Sitter black hole and derive some conditions on the stress tensor for the regularity of the Hartle-Hawking state.
Acoustic clouds: standing sound waves around a black hole analogue
Carolina L. Benone; Luis C. B. Crispino; Carlos Herdeiro; Eugen Radu
2015-01-28
Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic black holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models.
Thermodynamic Relations for Kiselev and Dilaton Black Hole
Bushra Majeed; Mubasher Jamil; Parthapratim Pradhan
2015-08-24
We investigate the thermodynamics and phase transition for Kiselev black hole and dilaton black hole. Speci?cally we consider Reissner Nordstrom black hole surrounded by radiation and dust, and Schwarzschild black hole surrounded by quintessence, as special cases of Kiselev solution. We have calculated the products relating the surface gravities, surface temperatures, Komar energies, areas, entropies, horizon radii and the irreducible masses at the Cauchy and the event horizons. It is observed that the product of surface gravities, surface temperature product and product of Komar energies at the horizons are not universal quantities for the Kiselev solutions while products of areas and entropies at both the horizons are independent of mass of the above mentioned black holes (except for Schwarzschild black hole surrounded by quintessence). For charged dilaton black hole, all the products vanish. First law of thermodynamics is also veri?ed for Kiselev solutions. Heat capacities are calculated and phase transitions are observed, under certain conditions.
Quantization of black holes by analogy with hydrogen atoms
Chang Liu; Yan-Gang Miao; Yu-Mei Wu; Yu-Hao Zhang
2015-11-16
We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Quantization of black holes by analogy with hydrogen atoms
Liu, Chang; Wu, Yu-Mei; Zhang, Yu-Hao
2015-01-01
We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Quantization of black holes by analogy with hydrogen atoms
Chang Liu; Yan-Gang Miao; Yu-Mei Wu; Yu-Hao Zhang
2015-11-23
We suggest a proposal of quantization for black holes that is based on an analogy between a black hole and a hydrogen atom. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of non-extreme black holes are chosen to be the probability densities of excited states with no angular momenta. Consequently, it is logical to accept quantization of mean radii of hydrogen atoms as that of black hole horizons. In this way, quantization of total black hole masses is deduced. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.
Energy Extraction from Spinning Black Holes via Relativistic Jets
Ramesh Narayan; Jeffrey E. McClintock; Alexander Tchekhovskoy
2013-03-12
It has for long been an article of faith among astrophysicists that black hole spin energy is responsible for powering the relativistic jets seen in accreting black holes. Two recent advances have strengthened the case. First, numerical general relativistic magnetohydrodynamic simulations of accreting spinning black holes show that relativistic jets form spontaneously. In at least some cases, there is unambiguous evidence that much of the jet energy comes from the black hole, not the disk. Second, spin parameters of a number of accreting stellar-mass black holes have been measured. For ballistic jets from these systems, it is found that the radio luminosity of the jet correlates with the spin of the black hole. This suggests a causal relationship between black hole spin and jet power, presumably due to a generalized Penrose process.
The Role of Primordial Kicks on Black Hole Merger Rates
Miroslav Micic; Tom Abel; Steinn Sigurdsson
2006-09-15
Primordial stars are likely to be very massive >30 Msun, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos. We expect primordial stars to form in halos in the mass range 10^6-10^10 Msun. Some of these early black holes, formed at redshifts z>10, could be the seed black hole for a significant fraction of the supermassive black holes found in galaxies in the local universe. If the black hole descendants of the primordial stars exist, their mergers with nearby supermassive black holes may be a prime candidate for long wavelength gravitational wave detectors. We simulate formation and evolution of dark matter halos in LambdaCDM universe. We seed high-redshift dark matter halos with early black holes, and explore the merger history of the host halos and the implications of black hole's kick velocities arising from their coalescence. The central concentration of low mass early black holes in present day galaxies is reduced if they experience even moderate kicks of tens of km/s. Even such modest kicks allow the black holes to leave their parent halo, which consequently leads to dynamical friction being less effective on the low mass black holes that were ejected, compared to those still embedded in their parent halos. Therefore, merger rates with central supermassive black holes in the largest halos may be reduced by more than an order of magnitude. Using analytical and illustrative cosmological N-body simulations, we quantify the role of kicks on the merger rates of black holes formed from massive metal free stars with supermassive black holes in present day galaxies.
Absorption probability of neutrino fields and Hawking radiation
Koray Düzta?
2015-05-14
We analyse the scattering of neutrino fields (massless spin 1/2 fields) from Kerr black holes. Adopting the notation of Teukolsky and Press, we derive the connection relation between the normalizations of ingoing and outgoing waves at the horizon and at infinity. It turns out that the connection relation for neutrino waves neither depends on the frequency $\\omega$ and angular momentum quantum numbers $l,m$ of the wave, nor on the black hole parameters $M,a$. As a result of that the absorption probability of neutrino fields $\\Gamma_{lm}(\\omega)$ which determines the average number of neutrinos emitted in the mode $(\\omega,l,m)$ in Hawking radiation, does not explicitly depend on the frequency $\\omega$ and angular momentum quantum numbers $l,m$. The form of $\\Gamma$ only in terms of Teukolsky's normalizations at infinity and at the horizon is derived. This is another aspect in which neutrino fields are essentially different than bosonic fields. The independence of the absorption probability of all parameters, also implies a violation of cosmic censorship since an extremal Kerr black hole can absorb modes carrying less energy than angular momentum. This is in accord with a recent work of the author evaluating the classical interaction of Kerr black holes with neutrino fields.
José P. S. Lemos
2013-12-27
The analogy between sound wave propagation and light waves led to the study of acoustic holes, the acoustic analogues of black holes. Many black hole features have their counterparts in acoustic holes. The Kerr metric, the rotating metric for black holes in general relativity, has as analogue the draining bathtub metric, a metric for a rotating acoustic hole. Here we report on the progress that has been made in the understanding of features, such as quasinormal modes and tails, superresonance, and instabilities when the hole is surrounded by a reflected mirror, in the draining bathtub metric. Given then the right settings one can build up from these instabilities an apparatus that stores energy in the form of amplified sound waves. This can be put to wicked purposes as in a bomb, or to good profit as in a sonic plant.
Band, Yehuda B.
T-shaped quantum wires in magnetic fields: Weakly confined magnetoexcitons beyond the diamagnetic at vanishing magnetic field26 to B 0. Exciton states for interacting electron-hole pairs confined to a T-particle states confined to the T intersection in a magnetic field and then using these single- particle states
Black Hole Portal into Hidden Valleys
Sergei Dubovsky; Victor Gorbenko
2010-12-13
Superradiant instability turns rotating astrophysical black holes into unique probes of light axions. We consider what happens when a light axion is coupled to a strongly coupled hidden gauge sector. In this case superradiance results in an adiabatic increase of a hidden sector CP-violating $\\theta$-parameter in a near horizon region. This may trigger a first order phase transition in the gauge sector. As a result a significant fraction of a black hole mass is released as a cloud of hidden mesons and can be later converted into electromagnetic radiation. This results in a violent electromagnetic burst. The characteristic frequency of such bursts may range approximately from 100 eV to 100 MeV.
Puncture Evolution of Schwarzschild Black Holes
J. David Brown
2008-01-15
The moving puncture method is analyzed for a single, non-spinning black hole. It is shown that the puncture region is not resolved by current numerical codes. As a result, the geometry near the puncture appears to evolve to an infinitely long cylinder of finite areal radius. The puncture itself actually remains at spacelike infinity throughout the evolution. In the limit of infinite resolution the data never become stationary. However, at any reasonable finite resolution the grid points closest to the puncture are rapidly drawn into the black hole interior by the Gamma-driver shift condition. The data can then evolve to a stationary state. These results suggest that the moving puncture technique should be viewed as a type of "natural excision".
The hydraulic jump as a white hole
G. E. Volovik
2005-10-21
In the geometry of the circular hydraulic jump, the velocity of the liquid in the interior region exceeds the speed of capillary-gravity waves (ripplons), whose spectrum is `relativistic' in the shallow water limit. The velocity flow is radial and outward, and thus the relativistic ripplons cannot propagating into the interior region. In terms of the effective 2+1 dimensional Painleve-Gullstrand metric appropriate for the propagating ripplons, the interior region imitates the white hole. The hydraulic jump represents the physical singularity at the white-hole horizon. The instability of the vacuum in the ergoregion inside the circular hydraulic jump and its observation in recent experiments on superfluid 4He by E. Rolley, C. Guthmann, M.S. Pettersen and C. Chevallier in physics/0508200 are discussed.
Hybrid black-hole binary initial data
Bruno C. Mundim; Bernard J. Kelly; Yosef Zlochower; Hiroyuki Nakano; Manuela Campanelli
2010-12-04
Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class.Quant.Grav.27:114005,2010], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculation was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features.
Slant hole completion test. Final report
Mann, R.L.
1993-07-01
One of the Department of Energy`s (DOE) Strategies and Objectives in the Natural Gas Program is to conduct activities to transfer technology from R&D programs to potential users. The Slant Hole Completion Test has achieved exactly this objective. The Slant Hole site is essentially the same as the Multiwell site and is located in the southeastern portion of the Piceance Basin near Rifle, Colorado. The Piceance Basin is typical of the Western low permeability basins that contain thick sequences of sands, silts and coals deposited during the Cretaceous period. These sequences contain vast amounts of natural gas but have proven to be resistant to commercial production because of the low permeability of the host rocks. Using the knowledge gained from the DOE`s earlier Multiwell experiment, the SHCT-1 was drilled to demonstrate that by intersecting the natural fractures found in these ``tight rocks,`` commercial gas production can be obtained.
Phase Structure of Higher Spin Black Holes
Abhishek Chowdhury; Arunabha Saha
2015-02-12
We revisit the study of the phase structure of higher spin black holes carried out in arXiv$:1210.0284$ using the "canonical formalism". In particular we study the low as well as high temperature regimes. We show that the Hawking-Page transition takes place in the low temperature regime. The thermodynamically favoured phase changes from conical surplus to black holes and then again to conical surplus as we increase temperature. We then show that in the high temperature regime the diagonal embedding gives the appropriate description. We also give a map between the parameters of the theory near the IR and UV fixed points. This makes the "good" solutions near one end map to the "bad" solutions near the other end and vice versa.
Janossy,A.; Nagy, K.; Feher, T.; Mihaly, L.; Erb, A.
2007-01-01
We present a series of electron spin resonance (ESR) and infrared transmission experiments in antiferromagnetic (AF), lightly hole-doped YBa{sub 2}Cu{sub 3}O{sub 6} in search for the effect of a spatially inhomogeneous ground state on the magnetic and electric properties. Crystal compositions were Ca{sub x}Gd{sub y}Y{sub 1-x-y}Ba{sub 2}Cu{sub 3}O{sub 6} with x=0 , 0.008, 0.02, and 0.03 and y{approx}0.01 . Gd{sup 3+} ESR satellites from sites with first-neighbor Ca atoms show that holes are not preferentially localized at low temperatures in the vicinity of Ca dopants. We mapped by multifrequency Gd{sup 3+} ESR the AF domain structure as a function of hole concentration, temperature, and magnetic fields up to 8T . We attribute the hole-doping-induced rotation of the magnetic easy axis from collateral to diagonal (with respect to the tetragonal CuO{sub 2} lattice) to the pinning of the AF magnetization to a static modulation or a phase-separated network of the hole density. The dominantly fourfold symmetry of pinning suggests that the hole density network has this symmetry also and is not an array of stripes. At higher temperatures the pinning to the diagonal direction becomes weak and the possibility of domain wall fluctuations is discussed. There is no magnetic field dependence and no in-plane anisotropy of the infrared transmission polarized in the CuO{sub 2} planes in an x=0.02 crystal placed in magnetic fields up to 12T . Thus, the network of holes is rigid and is not affected by magnetic fields that are, however, strong enough to rotate the AF magnetization into a single domain.
Hairy black hole entropy and the role of solitons in three dimensions
Francisco Correa; Cristian Martinez; Ricardo Troncoso
2012-02-13
Scalar fields minimally coupled to General Relativity in three dimensions are considered. For certain families of self-interaction potentials, new exact solutions describing solitons and hairy black holes are found. It is shown that they fit within a relaxed set of asymptotically AdS boundary conditions, whose asymptotic symmetry group coincides with the one for pure gravity and its canonical realization possesses the standard central extension. Solitons are devoid of integration constants and their (negative) mass, fixed and determined by nontrivial functions of the self-interaction couplings, is shown to be bounded from below by the mass of AdS spacetime. Remarkably, assuming that a soliton corresponds to the ground state of the sector of the theory for which the scalar field is switched on, the semiclassical entropy of the corresponding hairy black hole is exactly reproduced from Cardy formula once nonvanishing lowest eigenvalues of the Virasoro operators are taking into account, being precisely given by the ones associated to the soliton. This provides further evidence about the robustness of previous results, for which the ground state energy instead of the central charge appears to play the leading role in order to reproduce the hairy black hole entropy from a microscopic counting.
Are Ultra Long Gamma Ray Bursts powered by a black hole spinning down?
Nathanail, Antonios
2015-01-01
Gamma-ray bursts (GRBs) are violent explosions, coming from cosmological distances. They are detected in gamma-rays (also X-rays, UV, optical, radio) almost every day, and have typical durations of a few seconds to a few minutes. Some GRBs have been reported with extraordinary duration of 10^4 sec. These are called Ultra Long GRBs. It has been debated whether these form a new distinct class of events or whether they are similar to long GRBs. According to Blandford & Znajek (1977), the spin energy of a rotating black hole can be extracted electromagnetically, should the hole be endowed with a magnetic field supported by electric currents in a surrounding disk. We argue that this can be the case for the central engines of GRBs and we show that the duration of the burst depends on the magnetic flux accumulated on the event horizon of the black hole. We thus estimate the surface magnetic field of a possible progenitor star, and we conclude that an Ultra Long GRB may originate from a progenitor star with a rel...
Adams, A.I.; Chipera, S.; Counce, D.; Gardner, J.; Goff, S.; Goff, F.; Heiken, G.; Laughlin, A.W.; Musgrave, J.; Trujillo, P.E. Jr. (Los Alamos National Lab., NM (United States)); Aycinena, S.; Martinelli, L. (Swissboring Overseas Corp. Ltd., Guatemala City (Guatemala)); Castaneda, O.; Revolorio, M.; Roldan, A. (Unidad de Desarrollo Geotermico, Guatemala City (Guatemala). Inst. Nacional de Electrificacion); D
1992-02-01
Results of geological, volcanological, hydrogeochemical, and geophysical field studies conducted in 1988 and 1989 at the Tecuamburro volcano geothermal site in Guatemala indicated that there is a substantial shallow heat source beneath the area of youngest volcanism. To obtain information on subsurface temperatures and temperature gradients, stratigraphy, hydrothermal alteration, fracturing, and possible inflows of hydrothermal fluids, a geothermal gradient core hole (TCB-1) was drilled to 808 m low on the northern flank of the Tecuamburro volcano Complex, 300 km south of a 300-m-diameter phreatic crater, Laguna Ixpaco, dated at 2,910 years. Gases from acid-sulfate springs near Laguna Ixpaco consistently yield maximum estimated subsurface temperatures of 250--300{degrees}C. The temperature versus depth curve from TCB-1 does not show isothermal conditions and the calculated thermal gradients from 500--800 m is 230{degrees}C/km. Bottom hole temperature is 238{degrees}C. Calculated heat flow values are nearly 9 heat flow units (HFU). The integration of results from the TCB-1 gradient core hole with results from field studies provides strong evidence that the Tecuamburro area holds great promise for containing a commercial geothermal resource.
Myers-Perry black holes with scalar hair and a mass gap: unequal spins
Carlos Herdeiro; Jutta Kunz; Eugen Radu; Bintoro Subagyo
2015-05-10
We construct rotating boson stars and Myers-Perry black holes with scalar hair (MPBHsSH) as fully non-linear solutions of five dimensional Einstein gravity minimally coupled to a complex, massive scalar field. The MPBHsSH are, in general, regular on and outside the horizon, asymptotically flat, and possess angular momentum in a single rotation plane. They are supported by rotation and have no static limit. Such hairy BHs may be thought of as bound states of boson stars and singly spinning, vacuum MPBHs and inherit properties of both these building blocks. When the horizon area shrinks to zero, the solutions reduce to (in a single plane) rotating boson stars; but the extremal limit also yields a zero area horizon, as for singly spinning MPBHs. Similarly to the case of equal angular momenta, and in contrast to Kerr black holes with scalar hair, singly spinning MPBHsSH are disconnected from the vacuum black holes, due to a mass gap. We observe that for the general case, with two unequal angular momenta, the equilibrium condition for the existence of MPBHsSH is $w=m_1\\Omega_1+m_2\\Omega_2$, where $\\Omega_i$ are the horizon angular velocities in the two independent rotation planes and $w,m_i$, $i=1,2$, are the scalar field's frequency and azimuthal harmonic indices.
The Black Hole in the Compact, High-dispersion Galaxy NGC 1271
Walsh, Jonelle L; Gebhardt, Karl; Y?ld?r?m, Ak?n; Gültekin, Kayhan; Husemann, Bernd; Richstone, Douglas O
2015-01-01
Located in the Perseus cluster, NGC 1271 is an early-type galaxy with a small effective radius of 2.2 kpc and a large stellar velocity dispersion of 276 km/s for its K-band luminosity of 8.9x10^{10} L_sun. We present a mass measurement for the black hole in this compact, high-dispersion galaxy using observations from the integral field spectrograph NIFS on the Gemini North telescope assisted by laser guide star adaptive optics, large-scale integral field unit observations with PPAK at the Calar Alto Observatory, and Hubble Space Telescope WFC3 imaging observations. We are able to map out the stellar kinematics on small spatial scales, within the black hole sphere of influence, and on large scales that extend out to four times the galaxy's effective radius. We find that the galaxy is rapidly rotating and exhibits a sharp rise in the velocity dispersion. Through the use of orbit-based stellar dynamical models, we determine that the black hole has a mass of (3.0^{+1.0}_{-1.1}) x 10^9 M_sun and the H-band stellar...
Black Hole Radiation with Modified Dispersion Relation in Tunneling Paradigm: Free-fall Frame
Wang, Peng; Ying, Shuxuan
2015-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass $m_{p}$. The corrections to the Hawking temperature are calculated for massive and charged particles to $\\mathcal{O}\\left( m_{p}^{-2}\\right) $ and neutral and massless particles with $\\lambda=0$ to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is...
Charged Cylindrical Black Holes in Conformal Gravity
Jackson Levi Said; Joseph Sultana; Kristian Zarb Adami
2013-01-04
Considering cylindrical topology we present the static solution for a charged black hole in conformal gravity. We show that unlike the general relativistic case there are two different solutions, both including a factor that when set to zero recovers the familiar static charged black string solution in Einstein's theory. This factor gives rise to a linear term in the potential that also features in the neutral case and may have significant ramifications for particle trajectories.
Big Bang Nucleosynthesis and Primordial Black Holes
C. Sivaram; Kenath Arun
2010-06-28
There are ongoing efforts in detecting Hawking radiation from primordial black holes (PBH) formed during the early universe. Here we put an upper limit on the PBH number density that could have been formed prior to the big bang nucleosynthesis era, based on the constraint that the PBH evaporation energy consisting of high energy radiation not affect the observed abundances' of elements, by disintegrating the nuclei.
Thermodynamics and Luminosities of Rainbow Black Holes
Benrong Mu; Peng Wang; Haitang Yang
2015-07-14
Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As a result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is \\textquotedblleft Gravity's rainbow", where the spacetime background felt by a test particle would depend on its energy. Focusing on the \\textquotedblleft Amelino-Camelia dispersion relation" which is $E^{2}=m^{2}+p^{2}\\left[ 1-\\eta\\left( E/m_{p}\\right) ^{n}\\right] $ with $n>0$, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of $\\eta$ and $n$ in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with $\\eta<0$ and $n\\geq2$. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute luminosities of a 2D black hole, a Schwarzschild one and a static uncharged black string. It is found that the luminosities can be significantly suppressed or boosted depending on the values of $\\eta$ and $n$.
Rotating black hole solutions with quintessential energy
Toshmatov, Bobir; Ahmedov, Bobomurat
2015-01-01
Quintessential dark energy with density $\\rho$ and pressure $p$ is governed by an equation of state of the form $p=-\\omega_{q}\\rho$ with the quintessential parameter $\\omega_q\\in(-1;-1/3)$. We derive the geometry of quintessential rotating black holes, generalizing thus the Kerr spacetimes. Then we study the quintessential rotating black hole spacetimes with the special value of $\\omega_q = -2/3$ when the resulting formulae are simple and easily tractable. We show that such special spacetimes can exist for dimensionless quintessential parameter $c<1/6$ and determine the critical rotational parameter $a_0$ separating the black hole and naked singularity spacetime in dependence on the quintessential parameter $c$. For the spacetimes with $\\omega_q = 2/3$ we present the integrated geodesic equations in separated form and study in details the circular geodetical orbits. We give radii and parameters of the photon circular orbits, marginally bound and marginally stable orbits. We stress that the outer boundary o...
Probing Dark Energy with Black Hole Binaries
Laura Mersini-Houghton; Adam Kelleher
2008-08-25
The equation of state (EoS) of dark energy $w$ remains elusive despite enormous experimental efforts to pin down its value and its time variation. Yet it is the single most important handle we have in our understanding of one of the most mysterious puzzle in nature, dark energy. This letter proposes a new method for measuring the EoS of dark energy by using the gravitational waves (GW) of black hole binaries. The method described here offers an alternative to the standard way of large scale surveys. It is well known that the mass of a black hole changes due to the accretion of dark energy but at an extremely slow rate. However, a binary of supermassive black holes (SBH) radiates gravitational waves with a power proportional to the masses of these accreting stars and thereby carries information on dark energy. These waves can propagate through the vastness of structure in the universe unimpeded. The orbital changes of the binary, induced by the energy loss from gravitational radiation, receive a large contribution from dark energy accretion. This contribution is directly proportional to $(1+w)$ and is dominant for SBH binaries with separation $R \\ge 1000$ parsec, thereby accelerating the merging process for $w > -1$ or ripping the stars apart for phantom dark energy with $w < -1$. Such orbital changes, therefore $w$, can be detected with LIGO and LISA near merging time, or with X-ray and radio measurements of Chandra and VLBA experiments.
Sayan K. Chakrabarti
2007-02-01
We obtain the quasinormal modes for tensor perturbations of Gauss-Bonnet (GB) black holes in $d=5, 7, 8$ dimensions and vector perturbations in $d = 5, 6, 7$ and 8 dimensions using third order WKB formalism. The tensor perturbation for black holes in $d=6$ is not considered because of the fact that it is unstable to tensor mode perturbations. In the case of uncharged GB black hole, for both tensor and vector perturbations, the real part of the QN frequency increases as the Gauss-Bonnet coupling ($\\alpha'$) increases. The imaginary part first decreases upto a certain value of $\\alpha'$ and then increases with $\\alpha'$ for both tensor and vector perturbations. For larger values of $\\alpha'$, the QN frequencies for vector perturbation differs slightly from the QN frequencies for tensorial one. It has also been shown that as $\\alpha' \\to 0$, the quasinormal mode frequency for tensor and vector perturbation of the Schwarzschild black hole can be obtained. We have also calculated the quasinormal spectrum of the charged GB black hole for tensor perturbations. Here we have found that the real oscillation frequency increases, while the imaginary part of the frequency falls with the increase of the charge. We also show that the quasinormal frequencies for scalar field perturbations and the tensor gravitational perturbations do not match as was claimed in the literature. The difference in the result increases if we increase the GB coupling.
Non-linear Plasma Wake Growth of Electron Holes
Hutchinson, I H; Zhou, C
2015-01-01
An object's wake in a plasma with small Debye length that drifts \\emph{across} the magnetic field is subject to electrostatic electron instabilities. Such situations include, for example, the moon in the solar wind wake and probes in magnetized laboratory plasmas. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the plasma wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of electron to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that electron holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable...
Jones, N.O.
1983-03-01
Geothermal resource investigation field efforts in the Beowawe Geysers Area, Eureka County, Nevada are described. The objectives included acquisition of geotechnical data for understanding the nature and extent of the geothermal resource boundaries south of the known resource area. Fourteen shallow (<500 feet) temperature-gradient holes plus geophysics were used to select the site for a deep exploratory well, the Collins 76-17, which was completed to a total depth of 9005 feet. Maximum downhole recorded temperature was 311/sup 0/F, but no flow could be induced.
Higher spin gravity in 3D: black holes, global charges and thermodynamics
Alfredo Perez; David Tempo; Ricardo Troncoso
2013-09-05
Global charges and thermodynamic properties of three-dimensional higher spin black holes that have been recently found in the literature are revisited. Since these solutions possess a relaxed asymptotically AdS behavior, following the canonical approach, it is shown that the global charges, and in particular the mass, acquire explicit nontrivial contributions given by nonlinear terms in the deviations with respect to the reference background. It is also found that there are cases for which the first law of thermodynamics is fulfilled in the canonical ensemble, i.e., without work terms associated to the presence of higher spin fields, and remarkably, the semiclassical higher spin black hole entropy is exactly reproduced from Cardy formula.
Null geodesics and shadow of a rotating black hole in extended Chern-Simons modified gravity
Amarilla, Leonardo; Eiroa, Ernesto F.; Giribet, Gaston
2010-06-15
The Chern-Simons modification to general relativity in four dimensions consists of adding to the Einstein-Hilbert term a scalar field that couples to the first-class Pontryagin density. In this theory, which has attracted considerable attention recently, the Schwarzschild metric persists as an exact solution, and this is why this model resists several observational constraints. In contrast, the spinning black hole solution of the theory is not given by the Kerr metric but by a modification of it, so far only known for slow rotation and small coupling constant. In the present paper, we show that, in this approximation, the null geodesic equation can be integrated, and this allows us to investigate the shadow cast by a black hole. We discuss how, in addition to the angular momentum of the solution, the coupling to the Chern-Simons term deforms the shape of the shadow.
Comment on "Cyclotron resonance study of the electron and hole velocity in graphene monolayers"
S. C. Tiwari
2007-05-26
In this comment it is pointed out that the electron velocity of the same order as observed in graphene had been measured in GaAs submicron devices long ago. Particle- antiparticle asymmetry related with electron and hole effective masses in graphene seems puzzling as hole in a condensed matter system cannot be treated as anti-electron. It is argued that there should be a universal electrodynamics for QHE and superconductivity. In this context attention is drawn to the new approach based on massless electron and the interpretation that magnetic field represents angular momentum of the photon fluid. Measurement of electron velocity in graphene and GaAs in parallel is suggested for testing the massless electrodynamics.
Charged annular disks and Reissner-Nordstroem type black holes from extremal dust
Lora-Clavijo, F. D.; Ospina-Henao, P. A.; Pedraza, J. F.
2010-10-15
We present the first analytical superposition of a charged black hole with an annular disk of extremal dust. In order to obtain the solutions, we first solve the Einstein-Maxwell field equations for sources that represent disklike configurations of matter in confomastatic spacetimes by assuming a functional dependence among the metric function, the electric potential, and an auxiliary function, which is taken as a solution of the Laplace equation. We then employ the Lord Kelvin inversion method applied to models of finite extension in order to obtain annular disks. The structures obtained extend to infinity, but their total masses are finite and all the energy conditions are satisfied. Finally, we observe that the extremal Reissner-Nordstroem black hole can be embedded into the center of the disks by adding a boundary term in the inversion.
Reyes-Vera, Erick Gómez-Cardona, Nelson D.; Chesini, Giancarlo; Cordeiro, Cristiano M. B.; Torres, Pedro
2014-11-17
We report on the temperature sensitivity of the birefringence properties of a special kind of photonic crystal fiber containing two side holes filled with Indium metal. The modulation of the fiber birefringence is accomplished through the stress field induced by the expansion of the metal. Although the fiber was made at low gas pressures during the indium infiltration process, the birefringence showed anomalous property at a relatively low temperature value, which is completely different from those reported in conventional-like fibers with two holes filled with metal. By modeling the anisotropic changes induced by the metal expansion to the refractive index within the fiber, we are able to reproduce the experimental results. Our results have practical relevance for the design of devices based on this technology.
CFT dual of charged AdS black hole in the large dimension limit
Er-Dong Guo; Miao Li; Jia-Rui Sun
2015-12-28
We study the dual CFT description of the $d+1$-dimensional Reissner-Nordstr\\"om-Anti de Sitter (RN-AdS$_{d+1}$) black hole in the large dimension (large $d$) limit, both for the extremal and nonextremal cases. The central charge of the dual CFT$_2$ (or chiral CFT$_1$) is calculated for the near horizon near extremal geometry which possess an AdS$_2$ structure. Besides, the $Q$-picture hidden conformal symmetry in the nonextremal background can be naturally obtained by a probe charged scalar field in the large $d$ limit, without the need to input the usual limits to probe the hidden conformal symmetry. Furthermore, an new dual CFT description of the nonextremal RN-AdS$_{d+1}$ black hole is found in the large $d$ limit and the duality is analyzed by comparing the entropies, the absorption cross sections and the retarded Green's functions obtained both from the gravity and the dual CFT sides.
Quantum Black Holes and their Lepton Signatures at the LHC with CalCHEP
Alexander Belyaev; Xavier Calmet
2014-12-08
We discuss a field theoretical framework to describe the interactions of non-thermal quantum black holes (QBHs) with particles of the Standard Model. We propose a non-local Lagrangian to describe the production of these QBHs which is designed to reproduce the geometrical cross section for black hole production. This model is implemented into CalcHEP package and is publicly available at the High Energy Model Database (HEPMDB) for simulation of QBH events at the LHC and future colliders. We present the first phenomenological application of the QBH@HEPMDB model with spin-0 neutral QBH giving rise the $e^+e^-$ and $e\\mu$ signatures at the LHC@8TeV and LHC@13TeV and produce the respective projections for the LHC in terms of limits on the reduced Planck mass and the number of the extra-dimensions.
Universality of high-energy absorption cross sections for black holes
Decanini, Yves [Equipe Physique Theorique, SPE, UMR 6134 du CNRS et de l'Universite de Corse, Universite de Corse, Faculte des Sciences, B.P. 52, F-20250 Corte (France); Esposito-Farese, Gilles [GReCO, Institut d'Astrophysique de Paris, UMR 7095 du CNRS et de l'Universite Pierre et Marie Curie-Paris 6, 98bis boulevard Arago, F-75014 Paris (France); Folacci, Antoine [Equipe Physique Theorique, SPE, UMR 6134 du CNRS et de l'Universite de Corse, Universite de Corse, Faculte des Sciences, B.P. 52, F-20250 Corte (France); Centre de Physique Theorique, UMR 6207 du CNRS et des Universites Aix-Marseille 1 et 2 et de l'Universite du Sud Toulon-Var, CNRS-Luminy Case 907, F-13288 Marseille (France)
2011-02-15
We consider the absorption problem for a massless scalar field propagating in static and spherically symmetric black holes of arbitrary dimension endowed with a photon sphere. For this wide class of black holes, we show that the fluctuations of the high-energy absorption cross section are totally and very simply described from the properties (dispersion relation and damping) of the waves trapped near the photon sphere and therefore, in the eikonal regime, from the characteristics (orbital period and Lyapunov exponent) of the null unstable geodesics lying on the photon sphere. This is achieved by using Regge pole techniques. They permit us to make an elegant and powerful resummation of the absorption cross section and to extract then all the physical information encoded in the sum over the partial wave contributions. Our analysis induces moreover some consequences concerning Hawking radiation which we briefly report.
Quasi-hole solutions in finite noncommutative Maxwell-Chern-Simons theory
Jules Lambert; M. B. Paranjape
2007-05-15
We study Maxwell-Chern-Simons theory in 2 noncommutative spatial dimensions and 1 temporal dimension. We consider a finite matrix model obtained by adding a linear boundary field which takes into account boundary fluctuations. The pure Chern-Simons has been previously shown to be equivalent to the Laughlin description of the quantum Hall effect. With the addition of the Maxwell term, we find that there exists a rich spectrum of excitations including solitons with nontrivial "magnetic flux" and quasi-holes with nontrivial "charges", which we describe in this article. The magnetic flux corresponds to vorticity in the fluid fluctuations while the charges correspond to sources of fluid fluctuations. We find that the quasi-hole solutions exhibit a gap in the spectrum of allowed charge.
Accretion Processes On a Black Hole
Sandip K. Chakrabarti
1996-05-03
We describe astrophysical processes around a black hole keeping primarily the physics of accretion in mind. In Section 1, we briefly discuss the formation, evolution and detection of black holes. We also discuss the difference of flow properties around a black hole and a Newtonian star. In Section 2, we present past and present developments in the study of spherically accreting flows. We study the properties of Bondi flow with and without radiative transfer. In the presence of significant angular momentum, which is especially true in a binary system, matter will be accreted as a thin Keplerian disk. In Section 3, we discuss a large number of models of these disks including the more popular standard disk model. We present magnetized disk models as well. Since the angular momentum is high in these systems, rotational motion is the most dominant component compared to the radial or the vertical velocity components. In Section 4, we study thick disk models which are of low angular momentum but still have no significant radial motion. The accretion rates could be very high causing the flow to become radiation dominated and the disk to be geometrically thick. For low accretion rates, ion pressure supported disks are formed. In Section 5, we extensively discuss the properties of transonic flows which has with sub-Keplerian angular momentum. In the absence of shock discontinuities, these sub-Keplerian flows are basically advecting, similar to Bondi flows, close to the black holes, though far away they match Keplerian or sub-Keplerian disks. In presence of shocks, the post-shock flow becomes rotation dominated similar to thick disks. In Section 6, we present results of important numerical simulations of accretion flows. Significant results from the studies of evolution of viscous transonic flows are reported. In Section 7, we discuss some observational evidences of the black hole accretion. We also present a detailed model of a generalized accretion disk and present its spectra and compare with observations. In Section 8, we summarize the review and make concluding remarks.
Thermodynamic Product Formula for Taub-NUT Black Hole
Parthapratim Pradhan
2015-08-20
We derive various important thermodynamic relations of the inner and outer horizon in the background of Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \\emph{Lorentzian geometry}. We compare these properties with the properties of Reissner Nordstr{\\o}m black hole. We compute \\emph{area product, area sum, area minus and area division} of black hole horizons. We show that they all are not universal quantities. Based on these relations, we compute the area bound of all horizons. From area bound, we derive entropy bound and irreducible mass bound for both the horizons. We further study the stability of such black hole by computing the specific heat for both the horizons. It is shown that due to negative specific heat the black hole is thermodynamically unstable. All these calculations might be helpful to understanding the nature of black hole entropy both \\emph{interior} and exterior at the microscopic level.
Thermodynamic Product Formula for Taub-NUT Black Hole
Pradhan, Parthapratim
2015-01-01
We derive various important thermodynamic relations of the inner and outer horizon in the background of Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \\emph{Lorentzian geometry}. We compare these properties with the properties of Reissner Nordstr{\\o}m black hole. We compute \\emph{area product, area sum, area minus and area division} of black hole horizons. We show that they all are not universal quantities. Based on these relations, we compute the area bound of all horizons. From area bound, we derive entropy bound and irreducible mass bound for both the horizons. We further study the stability of such black hole by computing the specific heat for both the horizons. It is shown that due to negative specific heat the black hole is thermodynamically unstable. All these calculations might be helpful to understanding the nature of black hole entropy both \\emph{interior} and exterior at the microscopic level.
Destroying Kerr-Sen black holes with test particles
Haryanto M. Siahaan
2015-12-05
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 to a naked singularity when it captures charged massive test particles with angular momentum. A straightforward question then arises, do charged and rotating black holes in string theory possess the same property? In this paper we adopt the Wald's gedanken experiment in an effort to destroy a Kerr-Newman black hole's horizon 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 such black hole.
Articles which include chevron film cooling holes, and related processes
Bunker, Ronald Scott; Lacy, Benjamin Paul
2014-12-09
An article is described, including an inner surface which can be exposed to a first fluid; an inlet; and an outer surface spaced from the inner surface, which can be exposed to a hotter second fluid. The article further includes at least one row or other pattern of passage holes. Each passage hole includes an inlet bore extending through the substrate from the inlet at the inner surface to a passage hole-exit proximate to the outer surface, with the inlet bore terminating in a chevron outlet adjacent the hole-exit. The chevron outlet includes a pair of wing troughs having a common surface region between them. The common surface region includes a valley which is adjacent the hole-exit; and a plateau adjacent the valley. The article can be an airfoil. Related methods for preparing the passage holes are also described.
Thermodynamics of Charged Lovelock - AdS Black Holes
Prasobh C. B.; Jishnu Suresh; V. C. Kuriakose
2015-10-16
We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime.
Galaxy bulges and their massive black holes: a review
Alister W. Graham
2015-02-17
With references to both key and oft-forgotten pioneering works, this article starts by presenting a review into how we came to believe in the existence of massive black holes at the centres of galaxies. It then presents the historical development of the near-linear (black hole)-(host spheroid) mass relation, before explaining why this has recently been dramatically revised. Past disagreement over the slope of the (black hole)-(velocity dispersion) relation is also explained, and the discovery of sub-structure within the (black hole)-(velocity dispersion) diagram is discussed. As the search for the fundamental connection between massive black holes and their host galaxies continues, the competing array of additional black hole mass scaling relations for samples of predominantly inactive galaxies are presented.
Method and apparatus of assessing down-hole drilling conditions
Hall, David R. (Provo, UT); Pixton, David S. (Lehl, UT); Johnson, Monte L. (Orem, UT); Bartholomew, David B. (Springville, UT); Fox, Joe (Spanish Fork, UT)
2007-04-24
A method and apparatus for use in assessing down-hole drilling conditions are disclosed. The apparatus includes a drill string, a plurality of sensors, a computing device, and a down-hole network. The sensors are distributed along the length of the drill string and are capable of sensing localized down-hole conditions while drilling. The computing device is coupled to at least one sensor of the plurality of sensors. The data is transmitted from the sensors to the computing device over the down-hole network. The computing device analyzes data output by the sensors and representative of the sensed localized conditions to assess the down-hole drilling conditions. The method includes sensing localized drilling conditions at a plurality of points distributed along the length of a drill string during drilling operations; transmitting data representative of the sensed localized conditions to a predetermined location; and analyzing the transmitted data to assess the down-hole drilling conditions.
A Variational Principle for Asymptotically Randall-Sundrum Black Holes
Scott Fraser; Douglas M. Eardley
2015-07-28
We prove the following variational principle for asymptotically Randall-Sundrum (RS) black holes, based on the first law of black hole mechanics: Instantaneously static initial data that extremizes the mass yields a static black hole, for variations at fixed apparent horizon area, AdS curvature length, cosmological constant, brane tensions, and RS brane warp factors. This variational principle is valid with either two branes (RS1) or one brane (RS2), and is applicable to variational trial solutions.
Optoelectronic device with nanoparticle embedded hole injection/transport layer
Wang, Qingwu; Li, Wenguang; Jiang, Hua
2012-01-03
An optoelectronic device is disclosed that can function as an emitter of optical radiation, such as a light-emitting diode (LED), or as a photovoltaic (PV) device that can be used to convert optical radiation into electrical current, such as a photovoltaic solar cell. The optoelectronic device comprises an anode, a hole injection/transport layer, an active layer, and a cathode, where the hole injection/transport layer includes transparent conductive nanoparticles in a hole transport material.
Wang, Huan; He, X T
2015-01-01
An improved acceleration scheme to produce protons with controlled divergence and concentrated energy density is studied using ultrashort ultraintense (USUI) laser pulse interaction with a tailored hole-target in target normal sheath acceleration (TNSA) regime. Two-dimension-in-space and three-dimension-in-velocity (2D3V) particle-in-cell (PIC) simulations show that the tailored hole-target helps to reshape the sheath electric field and generate a transverse quasistatic electric field of $TV/m$ along the inner wall of the hole. The transverse electric field suppresses the transverse expansion of the proton beam effectively, as it tends to force the produced protons to focus inwards to the central axis, resulting in controlled divergence and concentrated energy density compared with that of a single plain target. The dependence of proton beam divergence and energy feature on depth of the hole is investigated in detail. A rough estimation of the hole depth ranges depending on $a_{0}$ of the incident laser is al...
Scalar solitons and the microscopic entropy of hairy black holes in three dimensions
Francisco Correa; Cristian Martinez; Ricardo Troncoso
2010-10-06
General Relativity coupled to a self-interacting scalar field in three dimensions is shown to admit exact analytic soliton solutions, such that the metric and the scalar field are regular everywhere. Since the scalar field acquires slow fall-off at infinity, the soliton describes an asymptotically AdS spacetime in a relaxed sense as compared with the one of Brown and Henneaux. Nevertheless, the asymptotic symmetry group remains to be the conformal group, and the algebra of the canonical generators possesses the standard central extension. For this class of asymptotic behavior, the theory also admits hairy black holes which raises some puzzles concerning an holographic derivation of their entropy \\`a la Strominger. Since the soliton is devoid of integration constants, it has a fixed (negative) mass, and it can be naturally regarded as the ground state of the "hairy sector", for which the scalar field is switched on. This assumption allows to exactly reproduce the semiclassical hairy black hole entropy from the asymptotic growth of the number of states by means of Cardy formula. Particularly useful is expressing the asymptotic growth of the number of states only in terms of the spectrum of the Virasoro operators without making any explicit reference to the central charges.
p-wave Holographic Superconductors from Born-Infeld Black Holes
Pankaj Chaturvedi; Gautam Sengupta
2015-01-28
We obtain (2+1) dimensional p-wave holographic superconductors from charged Born-Infeld black holes in the presence of massive charged vector fields in a bulk $AdS_4$ Einstein-Born-Infeld theory through the $AdS_4$-$CFT_3$ correspondence. Below a certain critical transition temperature the charged black hole develops vector hair that corresponds to charged vector condensate in the strongly coupled (2+1) dimensional boundary field theory that breaks both the $U(1)$ symmetry as well as the rotational invariance. The holographic free energy is computed for the boundary field theory which shows that the vector order parameter exhibits a rich phase structure involving zeroth order, first order, second order and retrograde phase transitions for different values of the backreaction and the Born-Infeld parameters. We numerically compute the ac conductivity for the p-wave superconducting phase of the strongly coupled (2+1) dimensional boundary field theory which also depends on the relative values of the parameters in the theory.
Thermal Fluctuations in a Charged AdS Black Hole
Pourhassan, B
2015-01-01
In this paper, we will analyze the effects of thermal fluctuations on a charged AdS black hole. This will be done by analyzing the corrections to black hole thermodynamics due to these thermal fluctuations. We will demonstrate that the entropy of this black hole get corrected by logarithmic term. We will also calculate other corrections to other important thermodynamic quantities for this black hole. Finally, we will use the corrected value of the specific heat to analyze the phase transition in this system.
Thermal Fluctuations in a Charged AdS Black Hole
B. Pourhassan; Mir Faizal
2015-08-12
In this paper, we will analyze the effects of thermal fluctuations on a charged AdS black hole. This will be done by analyzing the corrections to black hole thermodynamics due to these thermal fluctuations. We will demonstrate that the entropy of this black hole get corrected by logarithmic term. We will also calculate other corrections to other important thermodynamic quantities for this black hole. Finally, we will use the corrected value of the specific heat to analyze the phase transition in this system.
Thermal Gradient Holes At Breitenbush Hot Springs Area (Ingebritsen...
Thermal Gradient Holes At Breitenbush Hot Springs Area (Ingebritsen, Et Al., 1993) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal...
Thermal Gradient Holes At Neal Hot Springs Geothermal Area (U...
Thermal Gradient Holes At Neal Hot Springs Geothermal Area (U.S. Geothermal Inc., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal...
Thermal Gradient Holes At Lightning Dock Geothermal Area (Cunniff...
Thermal Gradient Holes At Lightning Dock Geothermal Area (Cunniff & Bowers, 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal...
Thermal Gradient Holes At Long Valley Caldera Geothermal Area...
Thermal Gradient Holes At Long Valley Caldera Geothermal Area (Sorey, Et Al., 1978) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal...
Compound and Elemental Analysis At Seven Mile Hole Area (Larson...
Of Older Hot Spring Alteration In Sevenmile Hole, Grand Canyon Of The Yellowstone River, Yellowstone Caldera, Wyoming Additional References Retrieved from "http:en.openei.orgw...
Thermal Gradient Holes At Long Valley Caldera Geothermal Area...
Thermal Gradient Holes At Long Valley Caldera Geothermal Area (Conservation, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal...
Thermal Gradient Holes At Long Valley Caldera Geothermal Area...
Area (Farrar, Et Al., 2003) Exploration Activity Details Location Long Valley Caldera Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 1998 - 2002...
Lovelock black hole thermodynamics in a string cloud model
Lee, Tae-Hun; Maharaj, Sunil D; Baboolal, Dharmanand
2015-01-01
The Lovelock theory is an extension of general relativity to higher dimensions. We study the Lovelock black hole for a string cloud model in arbitrary dimensional spacetime, and in turn also analyze its thermodynamical properties. Indeed, we compute the mass, temperature and entropy of the black hole and also perform a thermodynamical stability analysis. The phase structure suggests that the Hawking-Page phase transition is achievable. It turns out that the presence of the Lovelock terms and/or background string cloud completely changes the black hole thermodynamics. Interestingly, the entropy of a black hole is unaffected due to a background string cloud, but has a correction term due to Lovelock gravity.
Thermodynamics of rotating black holes in conformal gravity
Kamvar, Negin; Soroushfar, Saheb
2015-01-01
In this paper we consider a metric of a rotating black hole in conformal gravity. We calculate the thermodynamical quantities for this rotating black hole including Hawking temperature and entropy in four dimensional space-time, as we obtain the effective value of Komar angular momentum. The result is valid on the event horizon of the black hole, and at any radial distance out of it. Also we verify that the first law of thermodynamics will be held for this type of black hole.
Particle-Hole Optical Model: Fantasy or Reality?
M. H. Urin
2010-05-13
An attempt to formulate the optical model of particle-hole-type excitations (including giant resonances) is undertaken. The model is based on the Bethe--Goldstone equation for the particle-hole Green function. This equation involves a specific energy-dependent particle-hole interaction that is due to virtual excitation of many-quasiparticle configurations and responsible for the spreading effect. After energy averaging, this interaction involves an imaginary part. The analogy between the single-quasiparticle and particle-hole optical models is outlined.
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Benrong Mu; Peng Wang; Haitang Yang
2015-01-24
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.
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.
Energy Distribution of a Charged Regular Black Hole
Irina Radinschi
2000-11-20
We calculate the energy distribution of a charged regular black hole by using the energy-momentum complexes of Einstein and M{\\o}ller.
Thermal Gradient Holes At Blue Mountain Geothermal Area (Fairbank...
Thermal Gradient Holes At Blue Mountain Geothermal Area (Fairbank & Niggemann, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal...
Thermal Gradient Holes At Blue Mountain Geothermal Area (Fairbank...
Thermal Gradient Holes At Blue Mountain Geothermal Area (Fairbank & Ross, 1999) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient...
Thermal Gradient Holes At Lightning Dock Geothermal Area (Cunniff...
holes drilled References R.A. Cunniff, R.L. Bowers (2003) Final Report: Enhanced Geothermal Systems Technology Phase II: Animas Valley, New Mexico Additional References...
Thermal Gradient Holes At Walker-Lane Transitional Zone Region...
Zone Region (Pritchett, 2004) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date...
Free fall onto evaporating black holes at the quantum limit
Maurice H. P. M. van Putten
2015-11-11
Black hole space times evaporate in discrete steps due to remarkably slow Hawking radiation. We here identify evaporation with essentially extremal states at the limit of quantum computation, performing $2.7\\times 10^{79}$ bit calculations per photon emission in a one solar mass black hole. During evaporation, particles in free fall co-evolve satisfying $EM=$constant, where $E$ and $M$ denote the total mass energy-at-infinity of the particle and, respectively, black hole. Particles are hereby increasingly entangled with the black hole space-time over the course of its evaporation.
Thermal Gradient Holes At Central Nevada Seismic Zone Region...
Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient...
Ibar, Eduardo
2009-01-01
The two SCUBA HAlf-Degree Extragalactic Survey (SHADES) fields are amongst the richest places in the sky in terms of multi-wavelength coverage. They comprise an eastern section of the Lockman Hole (LH) and the central ...
The effects of fastener hole defects
Andrews, Scot D.
1991-01-01
) August 1991 ABSTRACT The Effects of Fastener Hole Defects. (August 1991) Scot D. Andrews, B. S. , Texas A8rM University Chair of Advisory Committee: Dr. Orden O. Ochoa The influence of drilling-induced defects, such as delamination, on the fatigue... ambient and elevated temperature wet conditions. Specimens were tested in a bearing tension frame to static failure in order to measure the failure load and to calculate pin bearing stress. From static test results, a fatigue load was selected as 66...
Collective Excitations in Electron-Hole Bilayers
Kalman, G. J. [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Hartmann, P.; Donko, Z. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Golden, K. I. [Department of Mathematics and Statistics and Department of Physics, University of Vermont, Burlington, Vermont 05401 (United States)
2007-06-08
We report a combined analytic and molecular dynamics analysis of the collective mode spectrum of a bipolar (electron-hole) bilayer in the strong coupling classical limit. A robust, isotropic energy gap is identified in the out-of-phase spectra, generated by the combined effect of correlations and of the excitation of the bound dipoles. In the in-phase spectra we identify longitudinal and transverse acoustic modes wholly maintained by correlations. Strong nonlinear generation of higher harmonics of the fundamental dipole oscillation frequency and the transfer of harmonics between different modes is observed.
Bindal, P. K.; Youngblood, David H.; Kozub, R. L.; Hoffmannpinther, P. H.
1975-01-01
V; measured o(0), 99Mo levels, deduced l, S; calculated J, 7(, 8, particle-core-coupling model. I. INTRODUCTION II. EXPERIMENTAL PROCEDURE AND RESULTS Recent studies of proton and neutron configura- tions of odd-A nuclei in the mass region of 90?100 have... of "'"'"Nb was obtained' ' using a quasiparticle core coupling model. Also, study of the ~'Mo(P, d)~Mo reaction' revealed three distinct groups of weakly excited neutron hole states, one corresponding to an l = 4 transf er and two corresponding...
Down-hole periodic seismic generator
Hardee, H.C.; Hills, R.G.; Striker, R.P.
1982-10-28
A down hole periodic seismic generator system is disclosed for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.
The static and dynamic characteristics of divergent tapered-bore hole-pattern gas seals
Carter, Jeremy John
2001-01-01
Experimental data is presented for three hole-pattern annular gas seals with differing diverging tapers machined in them. The holes are approximately 3.12 mm (.123 in) deep on average with a hole area to surface area ratio ...
Complementary junction heterostructure field-effect transistor
Baca, A.G.; Drummond, T.J.; Robertson, P.J.; Zipperian, T.E.
1995-12-26
A complimentary pair of compound semiconductor junction heterostructure field-effect transistors and a method for their manufacture are disclosed. The p-channel junction heterostructure field-effect transistor uses a strained layer to split the degeneracy of the valence band for a greatly improved hole mobility and speed. The n-channel device is formed by a compatible process after removing the strained layer. In this manner, both types of transistors may be independently optimized. Ion implantation is used to form the transistor active and isolation regions for both types of complimentary devices. The invention has uses for the development of low power, high-speed digital integrated circuits. 10 figs.
Complementary junction heterostructure field-effect transistor
Baca, Albert G. (Albuquerque, NM); Drummond, Timothy J. (Albuquerque, NM); Robertson, Perry J. (Albuquerque, NM); Zipperian, Thomas E. (Albuquerque, NM)
1995-01-01
A complimentary pair of compound semiconductor junction heterostructure field-effect transistors and a method for their manufacture are disclosed. The p-channel junction heterostructure field-effect transistor uses a strained layer to split the degeneracy of the valence band for a greatly improved hole mobility and speed. The n-channel device is formed by a compatible process after removing the strained layer. In this manner, both types of transistors may be independently optimized. Ion implantation is used to form the transistor active and isolation regions for both types of complimentary devices. The invention has uses for the development of low power, high-speed digital integrated circuits.
Paul M. Alsing
2015-02-04
In this paper we extend the investigation of Adami and Ver Steeg [Class. Quantum Grav. \\textbf{31}, 075015 (2014)] to treat the process of black hole particle emission effectively as the analogous quantum optical process of parametric down conversion (PDC) with a dynamical (depleted vs. non-depleted) `pump' source mode which models the evaporating black hole (BH) energy degree of freedom. We investigate both the short time (non-depleted pump) and long time (depleted pump) regimes of the quantum state and its impact on the Holevo channel capacity for communicating information from the far past to the far future in the presence of Hawking radiation. The new feature introduced in this work is the coupling of the emitted Hawking radiation modes through the common black hole `source pump' mode which phenomenologically represents a quantized energy degree of freedom of the gravitational field. This (zero-dimensional) model serves as a simplified arena to explore BH particle production/evaporation and back-action effects under an explicitly unitary evolution which enforces quantized energy/particle conservation. Within our analogous quantum optical model we examine the entanglement between two emitted particle/anti-particle and anti-particle/particle pairs coupled via the black hole (BH) evaporating `pump' source. We also analytically and dynamically verify the `Page information time' for our model which refers to the conventionally held belief that the information in the BH radiation becomes significant after the black hole has evaporated half its initial energy into the outgoing radiation. Lastly, we investigate the effect of BH particle production/evaporation on two modes in the exterior region of the BH event horizon that are initially maximally entangled, when one mode falls inward and interacts with the black hole, and the other remains forever outside and non-interacting.
Analysis of higher spin black holes with spin-4 chemical potential
Matteo Beccaria; Guido Macorini
2014-01-13
We consider the $AdS_{3}/CFT_{2}$ duality between certain coset WZW theories at large central charge and Vasiliev 3D higher spin gravity with a single complex field. On the gravity side, we discuss a higher spin black hole solution with chemical potential coupled to the spin-4 charge. We compute the perturbative expansion of the higher spin charges and of the partition function at high order in the chemical potential. The result is obtained with its exact dependence on the parameter $\\lambda$ characterising the symmetry algebra $\\mbox{hs}[\\lambda]$. The cases of $\\lambda=0,1$ are successfully compared with a CFT calculation. The special point $\\lambda=\\infty$, the Bergshoeff-Blencowe-Stelle limit, is also solved in terms of the exact generating function for the partition function. The thermodynamics of both the spin-4 and the usual spin-3 black holes is studied in order to discuss the $\\lambda$ dependence of the BTZ critical temperature $T_{\\rm BTZ}(\\lambda)$. In the spin-3 case, it is shown that $T_{\\rm BTZ}(\\lambda)$ converges for large $\\lambda$ to the critical point of the $\\lambda=\\infty$ known partition function previously found by the authors. In the spin-4 black hole, the picture is qualitatively similar and $T_{\\rm BTZ}(\\infty)$ is accurately determined by various numerical methods.
Graviton Emission in the Bulk by a Simply Rotating Black Hole
P. Kanti; Hideo Kodama; R. A. Konoplya; N. Pappas; A. Zhidenko
2010-06-07
In this work, we study the emission of tensor-type gravitational degrees of freedom from a higher-dimensional, simply rotating black hole in the bulk. The decoupled radial part of the corresponding field equation is first solved analytically in the limit of low-energy emitted particles and low-angular momentum of the black hole in order to derive the absorption probability. Both the angular and radial equations are then solved numerically, and the comparison of the analytical and numerical results show a very good agreement in the low and intermediate energy regimes. By using our exact, numerical results we compute the energy and angular momentum emission rates and their dependence on the spacetime parameters such as the number of additional spacelike dimensions and the angular momentum of the black hole. Particular care is given to the convergence of our results in terms of the number of modes taken into account in the calculation, and the multiplicity of graviton tensor modes that correspond to the same angular-momentum numbers.
Thermodynamics and Luminosities of Rainbow Black Holes
Mu, Benrong; Yang, Haitang
2015-01-01
Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As a result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is \\textquotedblleft Gravity's rainbow", where the spacetime background felt by a test particle would depend on its energy. Focusing on the \\textquotedblleft Amelino-Camelia dispersion relation" which is $E^{2}=m^{2}+p^{2}\\left[ 1-\\eta\\left( E/m_{p}\\right) ^{n}\\right] $ with $n>0$, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of $\\eta$ and $n$ in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with $\\eta<0$ and $n\\geq2$. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute lum...
Exact quasinormal modes for a special class of black holes
Julio Oliva; Ricardo Troncoso
2010-03-11
Analytic exact expressions for the quasinormal modes of scalar and electromagnetic perturbations around a special class of black holes are found in d\\ge3 dimensions. It is shown that, the size of the black hole provides a bound for the angular momentum of the perturbation. Quasinormal modes appear when this bound is fulfilled, otherwise the excitations become purely damped.
Modified Black Hole with Polar Jet and Vortex
T. Tmmalm
2001-12-06
There are many models relating an accretion disk of Black Hole to jet outflow. The herein heuristic model describes the continuation of an external accretion disk to an internal accretion disk for less than Black Hole horizon, and subsequent polar jet outflow along polar axis out of polar vortex wherein the event horizon is no longer descriptive.
Pair Production of Topological anti de Sitter Black Holes
R. B. Mann
1996-07-28
The pair creation of black holes with event horizons of non-trivial topology is described. The spacetimes are all limiting cases of the cosmological $C$ metric. They are generalizations of the $(2+1)$ dimensional black hole and have asymptotically anti de Sitter behaviour. Domain walls instantons can mediate their pair creation for a wide range of mass and charge.
Analysis of spherically symmetric black holes in Braneworld models
A. B. Pavan
2010-05-25
Research on black holes and their physical proprieties has been active on last 90 years. With the appearance of the String Theory and the Braneworld models as alternative descriptions of our Universe, the interest on black holes, in these context, increased. In this work we studied black holes in Braneworld models. A class of spherically symmetric black holes is investigaded as well its stability under general perturbations. Thermodynamic proprieties and quasi-normal modes are discussed. The black holes studied are the SM (zero mass) and CFM solutions, obtained by Casadio {\\it et al.} and Bronnikov {\\it et al.}. The geometry of bulk is unknown. However the Campbell-Magaard Theorem guarantees the existence of a 5-dimensional solution in the bulk whose projection on the brane is the class of black holes considered. They are stable under scalar perturbations. Quasi-normal modes were observed in both models. The tail behavior of the perturbations is the same. The entropy upper bound of a body absorved by the black holes studied was calculated. This limit turned out to be independent of the black hole parameters.
Perturbative Approach to the Quasinormal Modes of Dirty Black Holes
P. T. Leung; Y. T. Liu; W. -M. Suen; C. Y. Tam; K. Young
1999-03-08
Using a recently developed perturbation theory for uasinormal modes (QNM's), we evaluate the shifts in the real and imaginary parts of the QNM frequencies due to a quasi-static perturbation of the black hole spacetime. We show the perturbed QNM spectrum of a black hole can have interesting features using a simple model based on the scalar wave equation.
Accretion onto the First Stellar Mass Black Holes
Marcelo A. Alvarez; John H. Wise; Tom Abel
2008-11-07
The first stars in the universe, forming at redshifts z>15 in minihalos with masses of order 10^6 Msun, may leave behind black holes as their remnants. These objects could conceivably serve as "seeds" for much larger black holes observed at redshifts z~6. We study the growth of the remnant black holes through accretion including for the first time the emitted accretion radiation with adaptive mesh refinement cosmological radiation-hydrodynamical simulations. The effects of photo-ionization and heating dramatically affect the accretion flow from large scales, resulting in negligible mass growth of the black hole. We compare cases with the accretion luminosity included and neglected to show that the accretion radiation drastically changes the environment within 100 pc of the black hole, where gas temperatures are increased by an order of magnitude. The gas densities are reduced and further star formation in the same minihalo prevented for the two hundred million years of evolution we followed. These calculations show that even without the radiative feedback included most seed black holes do not gain mass as efficiently as has been hoped for in previous theories, implying that black hole remnants of Pop III stars that formed in minihalos are not likely to be the origin of miniquasars. Most importantly, however, these calculations demonstrate that if early stellar mass black holes are indeed accreting close to the Bondi-Hoyle rate with ten percent efficiency they have a dramatic local effect in regulating star formation in the first galaxies.
Filing Holes in Complex Surfaces Using Volumetric Diffusion
Kazhdan, Michael
components (red) Accurate filling requires knowledge of surface topology #12;Complications of Hole Filling components Complex hole geometry Construction of an arbitrary mesh can result in non-manifold surface Results of subsequent iterations are combined using a variation of alpha blending d0, v0=ds ,[ws0] di
Large rotating AdS black holes from fluid mechanics
Sayantani Bhattacharyya; Subhaneil Lahiri; R. Loganayagam; Shiraz Minwalla
2008-07-25
We use the AdS/CFT correspondence to argue that large rotating black holes in global AdS(D) spaces are dual to stationary solutions of the relativistic Navier-Stokes equations on S**(D-2). Reading off the equation of state of this fluid from the thermodynamics of non-rotating black holes, we proceed to construct the nonlinear spinning solutions of fluid mechanics that are dual to rotating black holes. In all known examples, the thermodynamics and the local stress tensor of our solutions are in precise agreement with the thermodynamics and boundary stress tensor of the spinning black holes. Our fluid dynamical description applies to large non-extremal black holes as well as a class of large non-supersymmetric extremal black holes, but is never valid for supersymmetric black holes. Our results yield predictions for the thermodynamics of all large black holes in all theories of gravity on AdS spaces, for example, string theory on AdS(5) x S**5 and M theory on AdS(4) x S**7 and AdS(7) x S**4.
A note on regular black holes in a brane world
Neves, J C S
2015-01-01
In this work, we show that regular black holes in a Randall-Sundrum-type brane world model are generated by the non-local bulk influence, expressed by a constant parameter in the brane metric, only in the spherical case. In the axial case (black holes with rotation), this influence forbids them.
Accretion Disks Around Black Holes: Twenty Five Years Later
Sandip K. Chakrabarti
1998-07-10
We study the progress of the theory of accretion disks around black holes in last twenty five years and explain why advective disks are the best bet in explaining varied stationary and non-stationary observations from black hole candidates. We show also that the recently proposed advection dominated flows are incorrect.
Electromagnetic Excitation of Rotating Black Holes and Relativistic Jets
A. Burinskii; E. Elizalde; S. R. Hildebrandt; G. Magli
2006-10-02
We show that electromagnetic excitations of rotating black holes can lead to the appearance of narrow singular beams which break up the black hole horizon forming a tube-like region which connects the interior and exterior. It is argued that this effect may be at the origin of jet formation.
Is the Universe the only existing Black Hole?
Andrea Gregori
2010-06-30
We investigate the physics of black holes in the light of the quantum theoretical framework proposed in [1]. It is argued that black holes are completely non-local objects, and that the only one which really exists is the universe itself.
Fuel injector Holes (Fabrication of Micro-Orifices for Fuel Injectors...
Office of Environmental Management (EM)
injector Holes (Fabrication of Micro-Orifices for Fuel Injectors) Fuel injector Holes (Fabrication of Micro-Orifices for Fuel Injectors) 2009 DOE Hydrogen Program and Vehicle...
Zhang, Sijie; Gillin, W. P., E-mail: w.gillin@qmul.ac.uk [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Willis, M. [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Gotto, R.; Roy, K. A.; Kreouzis, T. [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Rolfe, N. J. [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); University of Surrey, Guildford, Surrey GU2 5XH (United Kingdom)
2014-01-27
The change in current through an organic light emitting diode (OLED) when it is placed in a magnetic field has been dubbed organic magnetoresistance and provides a means to understand the spin interactions that are occurring in working devices. Whilst there are a wide range of interactions that have been proposed to be the cause of the measured effects, there is still a need to identify their individual roles and in particular how they respond to an applied magnetic field. In this work, we investigate the effect of changing the balance of electron and hole injection in a simple aluminium tris(8-hydroxyqinoline) based OLED and demonstrate that the triplet polaron interaction appears to be much stronger for electrons than for holes in this material.
Owen Pavel Fernández Piedra; Fidel Sosa; José L. Bernal-Castillo; Yulier Jimenez
2012-06-09
The aim of the present report is to study massless fermion perturbations outside five-dimensional stringy black holes with U(1) charges. The Dirac equation was numerically solved to obtain the time profiles for the evolving fermion fields, and the quasinormal frequencies at intermediate times are computed by numerical Prony fitting and semianalytical WKB expansion at sixth order. We also computed numerically the late-time power law decay factors, showing that there are in correspondence with previously reported results for the case of boson fields in higher dimensional odd space-times. The dependence of quasinormal frequencies with U(1) compactification charges are studied, and the stability of this class of higher dimensional black holes under fermion perturbations is established.
Fast Radio Bursts and Radio Transients from Black Hole Batteries
Mingarelli, Chiara M F; Lazio, T Joseph W
2015-01-01
Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS--BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is $20\\%-80\\%$ as luminous, given 0.5~ms timing resolution. The main burst is from the peak luminosity before merger. The post-merger burst follows from the NS magnetic ...
Rotating black holes, global symmetry and first order formalism
Laura Andrianopoli; Riccardo D'Auria; Paolo Giaccone; Mario Trigiante
2012-10-15
In this paper we consider axisymmetric black holes in supergravity and address the general issue of defining a first order description for them. The natural setting where to formulate the problem is the De Donder-Weyl-Hamilton-Jacobi theory associated with the effective two-dimensional sigma-model action describing the axisymmetric solutions. We write the general form of the two functions S_m defining the first-order equations for the fields. It is invariant under the global symmetry group G_(3) of the sigma-model. We also discuss the general properties of the solutions with respect to these global symmetries, showing that they can be encoded in two constant matrices belonging to the Lie algebra of G_(3), one being the Noether matrix of the sigma model, while the other is non-zero only for rotating solutions. These two matrices allow a G_(3)-invariant characterization of the rotational properties of the solution and of the extremality condition. We also comment on extremal, under-rotating solutions from this point of view.
Adaptive computation of gravitational waves from black hole interactions
Philippos Papadopoulos; Edward Seidel; Lee Wild
1998-02-27
We construct a class of linear partial differential equations describing general perturbations of non-rotating black holes in 3D Cartesian coordinates. In contrast to the usual approach, a single equation treats all radiative $\\ell -m$ modes simultaneously, allowing the study of wave perturbations of black holes with arbitrary 3D structure, as would be present when studying the full set of nonlinear Einstein equations describing a perturbed black hole. This class of equations forms an excellent testbed to explore the computational issues of simulating black spacetimes using a three dimensional adaptive mesh refinement code. Using this code, we present results from the first fully resolved 3D solution of the equations describing perturbed black holes. We discuss both fixed and adaptive mesh refinement, refinement criteria, and the computational savings provided by adaptive techniques in 3D for such model problems of distorted black holes.
Hypervelocity binary stars: smoking gun of massive binary black holes
Youjun Lu; Qingjuan Yu; D. N. C. Lin
2007-07-22
The hypervelocity stars recently found in the Galactic halo are expelled from the Galactic center through interactions between binary stars and the central massive black hole or between single stars and a hypothetical massive binary black hole. In this paper, we demonstrate that binary stars can be ejected out of the Galactic center with velocities up to 10^3 km/s, while preserving their integrity, through interactions with a massive binary black hole. Binary stars are unlikely to attain such high velocities via scattering by a single massive black hole or through any other mechanisms. Based on the above theoretical prediction, we propose a search for binary systems among the hypervelocity stars. Discovery of hypervelocity binary stars, even one, is a definitive evidence of the existence of a massive binary black hole in the Galactic center.
Gravitational Waves from Quasi-Circular Black Hole Binaries in Dynamical Chern-Simons Gravity
Kent Yagi; Nicolas Yunes; Takahiro Tanaka
2013-02-07
Dynamical Chern-Simons gravity cannot be strongly constrained with current experiments because it reduces to General Relativity in the weak-field limit. This theory, however, introduces modifications in the non-linear, dynamical regime, and thus, it could be greatly constrained with gravitational waves from the late inspiral of black hole binaries. We complete the first self-consistent calculation of such gravitational waves in this theory. For favorable spin-orientations, advanced ground-based detectors may improve existing solar-system constraints by 6 orders of magnitude.
Unconstrained hyperboloidal evolution of black holes in spherical symmetry with GBSSN and Z4c
Alex Vañó-Viñuales; Sascha Husa
2014-12-15
We consider unconstrained evolution schemes for the hyperboloidal initial value problem in numerical relativity as a promising candidate for the optimally efficient numerical treatment of radiating compact objects. Here, spherical symmetry already poses nontrivial problems and constitutes an important first step to regularize the resulting singular PDEs. We evolve the Einstein equations in their generalized BSSN and Z4 formulations coupled to a massless self-gravitating scalar field. Stable numerical evolutions are achieved for black hole initial data, and critically rely on the construction of appropriate gauge conditions.
Nucleon-nucleus optical potential in the particle-hole approach
C. Barbieri; B. K. Jennings
2005-01-27
Feshbach's projection formalism in the particle-hole model space leads to a microscopic description of scattering in terms of the many-body self-energy. To investigate the feasibility of this approach, an optical potential for O-16 is constructed starting from two previous calculations of the self-energy for this nucleus. The results reproduce the background phase shifts for positive parity waves and the resonances beyond the mean field. The latter can be computed microscopically for energies of astrophysical interest using Green's function theory.
Emanuele Berti; Vitor Cardoso; Jose A. Gonzalez; Ulrich Sperhake
2007-06-17
The ringdown phase following a binary black hole merger is usually assumed to be well described by a linear superposition of complex exponentials (quasinormal modes). In the strong-field conditions typical of a binary black hole merger, non-linear effects may produce mode coupling. Artificial mode coupling can also be induced by the black hole's rotation, if the radiation field is expanded in terms of spin-weighted spherical (rather than spheroidal) harmonics. Observing deviations from linear black hole perturbation theory requires optimal fitting techniques to extract ringdown parameters from numerical waveforms, which are inevitably affected by errors. So far, non-linear least-squares fitting methods have been used as the standard workhorse to extract frequencies from ringdown waveforms. These methods are known not to be optimal for estimating parameters of complex exponentials. Furthermore, different fitting methods have different performance in the presence of noise. The main purpose of this paper is to introduce the gravitational wave community to modern variations of a linear parameter estimation technique first devised in 1795 by Prony: the Kumaresan-Tufts and matrix pencil methods. Using "test" damped sinusoidal signals in Gaussian white noise we illustrate the advantages of these methods, showing that they have variance and bias at least comparable to standard non-linear least-squares techniques. Then we compare the performance of different methods on unequal-mass binary black hole merger waveforms. The methods we discuss should be useful both theoretically (to monitor errors and search for non-linearities in numerical relativity simulations) and experimentally (for parameter estimation from ringdown signals after a gravitational wave detection).
In what sense a neutron star-black hole binary is the holy grail for testing gravity?
Manjari Bagchi; Diego F. Torres
2014-07-29
Pulsars in binary systems have been very successful to test the validity of general relativity in the strong field regime. So far, such binaries include neutron star-white dwarf (NS-WD) and neutron star-neutron star (NS-NS) systems. It is commonly believed that a neutron star-black hole (NS-BH) binary will be much superior for this purpose. But in what sense is this true? Does it apply to all possible deviations?
In what sense a neutron star-black hole binary is the holy grail for testing gravity?
Bagchi, Manjari
2014-01-01
Pulsars in binary systems have been very successful to test the validity of general relativity in the strong field regime. So far, such binaries include neutron star-white dwarf (NS-WD) and neutron star-neutron star (NS-NS) systems. It is commonly believed that a neutron star-black hole (NS-BH) binary will be much superior for this purpose. But in what sense is this true? Does it apply to all possible deviations?
AdS-CFT Correspondence, Non-commutative Geometry and Holographic Superconductor in Magnetic Field
Souvik Pramanik; Subir Ghosh
2015-09-25
In this work, the effects of magnetic field on a Holographic Superconductor have been studied in non-commutative background through the AdS-CFT correspondence. The non-commutative correction has been incorporated here is the generalization of the Schwarzschild black hole metric in AdS. It has been found that the non-commutative effects tend to work against the black hole hair formation. This in turn shows negative effect on holographic superconductors. Indeed, it reduces the value of the critical magnetic field and furthermore the critical magnetic field vanishes before the temperature reaches to its critical value.
AdS-CFT Correspondence, Non-commutative Geometry and Holographic Superconductor in Magnetic Field
Souvik Pramanik; Subir Ghosh
2015-10-08
In this work, the effects of magnetic field on a Holographic Superconductor have been studied in non-commutative background through the AdS-CFT correspondence. The non-commutative correction has been incorporated here is the generalization of the Schwarzschild black hole metric in AdS. It has been found that the non-commutative effects tend to work against the black hole hair formation. This in turn shows negative effect on holographic superconductors. Indeed, it reduces the value of the critical magnetic field and furthermore the critical magnetic field vanishes before the temperature reaches to its critical value.
AdS-CFT Correspondence, Non-commutative Geometry and Holographic Superconductor in Magnetic Field
Pramanik, Souvik
2015-01-01
In this work, the effects of magnetic field on a Holographic Superconductor have been studied in non-commutative background through the AdS-CFT correspondence. The non-commutative correction has been incorporated here is the generalization of the Schwarzschild black hole metric in AdS. It has been found that the non-commutative effects tend to work against the black hole hair formation. This in turn shows negative effect on holographic superconductors. Indeed, it reduces the value of the critical magnetic field and furthermore the critical magnetic field vanishes before the temperature reaches to its critical value.
Coiled tubing sidetrack: Slaughter Field case history
Hightower, C.M.; Blount, C.G.; Ward, S.L.; Martin, R.F.; Cantwell, D.L.; Ackers, M.J.
1995-03-01
The paper describes the successful sidetrack of an oil well in the Slaughter Field in West Texas using coiled tubing (CT). Several first-time CT operations performed during this workover include: setting a whipstock in casing on CT; cutting a window with CT; using mud pulse measurement-while-drilling (MWD) with CT in a real well; use of a fluid-operated orientation tool for in-hole toolface changes; successful use of an autodriller to maintain weight on bit while drilling. Directional control of the sidetracked hole proved to be ineffective due to a surface software problem. The resultant wellbore was not horizontal as planned, but instead closely paralleled the original well for much of its length. However, the previously non-productive well flowed 1,000 barrels of fluid per day (BFPD) from the sidetrack following the workover.
Tachyonic field interacting with Scalar (Phantom) Field
Surajit Chattopadhyay; Ujjal Debnath
2009-01-29
In this letter, we have considered the universe is filled with the mixture of tachyonic field and scalar or phantom field. If the tachyonic field interacts with scalar or phantom field, the interaction term decays with time and the energy for scalar field is transferred to tachyonic field or the energy for phantom field is transferred to tachyonic field. The tachyonic field and scalar field potentials always decrease, but phantom field potential always increases.
Interface-induced heavy-hole/light-hole splitting of acceptors in silicon
Mol, J. A.; Salfi, J.; Simmons, M. Y.; Rogge, S.; Rahman, R.; Hsueh, Y.; Klimeck, G.; Miwa, J. A.
2015-05-18
The energy spectrum of spin-orbit coupled states of individual sub-surface boron acceptor dopants in silicon have been investigated using scanning tunneling spectroscopy at cryogenic temperatures. The spatially resolved tunnel spectra show two resonances, which we ascribe to the heavy- and light-hole Kramers doublets. This type of broken degeneracy has recently been argued to be advantageous for the lifetime of acceptor-based qubits [R. Ruskov and C. Tahan, Phys. Rev. B 88, 064308 (2013)]. The depth dependent energy splitting between the heavy- and light-hole Kramers doublets is consistent with tight binding calculations, and is in excess of 1?meV for all acceptors within the experimentally accessible depth range (<2?nm from the surface). These results will aid the development of tunable acceptor-based qubits in silicon with long coherence times and the possibility for electrical manipulation.