While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

1

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

area. The line extends 52 miles from the Palisades Dam in eastern Idaho to BPA's Goshen Substation south of Idaho Falls, Idaho. BPA began construction in 2008, replacing the...

2

Goshen North Wind Project | Open Energy Information

Goshen North Wind Project Goshen North Wind Project Jump to: navigation, search Name Goshen North Wind Project Facility Goshen North Wind Project Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner BP Wind Energy/Ridgeline Energy Developer BP Wind Energy/Ridgeline Energy Energy Purchaser Southern California Edison Co Location Bonneville County ID Coordinates 43.511043Â°, -111.886067Â° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":43.511043,"lon":-111.886067,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

3

Goshen County, Wyoming: Energy Resources | Open Energy Information

Goshen County, Wyoming: Energy Resources Goshen County, Wyoming: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 42.0334428Â°, -104.3791912Â° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.0334428,"lon":-104.3791912,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

4

Microsoft Word - CX-SwanValley-Goshen_GraniteCreekBoxCulvert_WEB.doc

Broader source: Energy.gov (indexed) [DOE]

4 4 SUBJECT: Environmental Clearance Memorandum Joe Johnson Natural Resource Specialist - TFBV-Kalispell Proposed Action: Replace existing bridge with a concrete box culvert at Granite Creek along Bonneville Power Administration's (BPA) Swan Valley-Goshen 161-kV transmission line. Budget Information: Work Order # 189268-01 PP&A Project No.: PP&A 2047 Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.3, Routine maintenance activities for structures, rights-of-way, and infrastructures, (such as roads), that are required to maintain infrastructures in a condition suitable for a facility to be used for its designated purpose. Location: The proposed project is located on Granite Creek along BPA's Swan Valley-Goshen

5

Black Holes as Conformal Field Theories on Horizons

We show that any nonextreme black hole can be described by a state with $L_0=E_R$ in a $D=2$ chiral conformal field theory with central charge $c=12E_R$ where $E_R$ is the dimensionless Rindler energy of the black hole. The theory lives in the very near horizon region, i.e. around the origin of Rindler space. Black hole hair is the momentum along the Euclidean dimensionless Rindler time direction. As evidence, we show that $D$--dimensional Schwarzschild black holes and $D=2$ dilatonic ones that are obtained from them by spherical reduction are described by the same conformal field theory states.

Halyo, Edi

2015-01-01T23:59:59.000Z

6

Port hole perturbations to the magnetic field in MST

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

095002 (17pp) doi:10.10880741-3335529095002 Port hole perturbations to the magnetic field in MST P J Fimognari 1 , A F Almagri 1 , J K Anderson 1 , D R Demers 2 , J S Sarff 1 ,...

7

Weak field limit of Reissner-Nordström black hole lensing

Science Journals Connector (OSTI)

We study gravitational lensing by a Reissner-Nordström black hole in the weak field limit. We obtain the basic equations for the deflection angle and time delay and find analytical expressions for the positions and amplifications of the primary and secondary images. Because of a net positive charge, the separation between images increases, but no change in the total magnification occurs.

Mauro Sereno

2004-01-13T23:59:59.000Z

8

Viscosity, Black Holes, and Quantum Field Theory

We review recent progress in applying the AdS/CFT correspondence to finite-temperature field theory. In particular, we show how the hydrodynamic behavior of field theory is reflected in the low-momentum limit of correlation functions computed through a real-time AdS/CFT prescription, which we formulate. We also show how the hydrodynamic modes in field theory correspond to the low-lying quasinormal modes of the AdS black p-brane metric. We provide a proof of the universality of the viscosity/entropy ratio within a class of theories with gravity duals and formulate a viscosity bound conjecture. Possible implications for real systems are mentioned.

D. T. Son; A. O. Starinets

2007-04-02T23:59:59.000Z

9

Characterizing asymptotically anti-de Sitter black holes with abundant stable gauge field hair

In the light of the "no-hair" conjecture, we revisit stable black holes in su(N) Einstein-Yang-Mills theory with a negative cosmological constant. These black holes are endowed with copious amounts of gauge field hair, and we address the question of whether these black holes can be uniquely characterized by their mass and a set of global non-Abelian charges defined far from the black hole. For the su(3) case, we present numerical evidence that stable black hole configurations are fixed by their mass and two non-Abelian charges. For general N, we argue that the mass and N-1 non-Abelian charges are sufficient to characterize large stable black holes, in keeping with the spirit of the "no-hair" conjecture, at least in the limit of very large magnitude cosmological constant and for a subspace containing stable black holes (and possibly some unstable ones as well).

Ben L. Shepherd; Elizabeth Winstanley

2012-02-07T23:59:59.000Z

10

Field Mapping At Seven Mile Hole Area (Larson, Et Al., 2009) | Open Energy

Seven Mile Hole Area (Larson, Et Al., 2009) Seven Mile Hole Area (Larson, Et Al., 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Field Mapping At Seven Mile Hole Area (Larson, Et Al., 2009) Exploration Activity Details Location Seven Mile Hole Area Exploration Technique Field Mapping Activity Date Usefulness not indicated DOE-funding Unknown Notes The distribution of hydrothermally altered rocks was mapped over about 1 km2 in the Sevenmile Hole area. Two to four kilogram hand samples located by a handheld GPS were collected from many outcrops K735for laboratory analyses References Peter B. Larson, Allison Phillips, David John, Michael Cosca, Chad Pritchard, Allen Andersen, Jennifer Manion (2009) A Preliminary Study Of Older Hot Spring Alteration In Sevenmile Hole, Grand Canyon Of The

11

Effective potential of a black hole in thermal equilibrium with quantum fields

Science Journals Connector (OSTI)

Expectation values of one-loop renormalized thermal equilibrium stress-energy tensors of free conformal scalars, spin-1/2 fermions, and U(1) gauge fields on a Schwarzschild black hole background are used as sources in the semiclassical Einstein equation. The back reaction and new equilibrium metric have been found at O(?) for each spin field in previous work. In this paper, the nature of the modified black hole spacetime is explored through calculations of the effective potential for null and timelike orbits. Significant novel features affecting the motions of both massive and massless test particles show up at lowest order in ?=(MPl/M)2<1, where M is the black hole mass, and MPl is the Planck mass. Specifically, we find an increase in the black hole capture cross sections, and the existence of a region near the black hole with a repulsive contribution, generated by the U(1) back reaction, to the gravitational force. There is no such effect for other spins. Extrapolating our results suggests a tendency towards the formation of stable circular orbits, but the result cannot be established in O(?): the change in the metric becomes large and it changes its signature. We also consider the back reaction arising from multiple fields, which ultimately should be useful for treating a black hole in equilibrium with field ensembles belonging to gauge theories. In certain circumstances, however, reliable results will require calculations beyond O(?).

David Hochberg; Thomas W. Kephart; James W. York; Jr.

1994-05-15T23:59:59.000Z

12

Spherical non-linear absorption of cosmological scalar fields onto a black hole

In this paper we track the non-linear spherical evolution of a massless scalar field onto a Schwarzschild black hole space-time as a first approximation to the accretion of cosmologically motivated classical scalar fields. We perform an analysis related to wave packets described by wave number and width. We study various values of the wave number k, and found that for k = 0 and width packets bigger than the Schwarzschild radius, the absorption is not total. In the cases we studied for k > 0, the black hole absorbs the total amount of energy density of the scalar field moving toward the horizon. Our results indicate that assuming spherical symmetry, in the non-linear regime, there are cases for which scalar fields are allowed to survive outside black holes and may eventually have life-times consistent with cosmological time scales.

F. S. Guzman; F. D. Lora-Clavijo

2012-01-17T23:59:59.000Z

13

Tidal coupling between members of a compact binary system can have an interesting and important influence on that binary's dynamical inspiral. Tidal coupling also distorts the binary's members, changing them (at lowest order) from spheres to ellipsoids. At least in the limit of fluid bodies and Newtonian gravity, there are simple connections between the geometry of the distorted ellipsoid and the impact of tides on the orbit's evolution. In this paper, we develop tools for investigating tidal distortions of rapidly rotating black holes using techniques that are good for strong-field, fast-motion binary orbits. We use black hole perturbation theory, so our results assume extreme mass ratios. We develop tools to compute the distortion to a black hole's curvature for any spin parameter, and for tidal fields arising from any bound orbit, in the frequency domain. We also develop tools to visualize the horizon's distortion for black hole spin $a/M \\le \\sqrt{3}/2$ (leaving the more complicated $a/M > \\sqrt{3}/2$ case to a future analysis). We then study how a Kerr black hole's event horizon is distorted by a small body in a circular, equatorial orbit. We find that the connection between the geometry of tidal distortion and the orbit's evolution is not as simple as in the Newtonian limit.

Stephen O'Sullivan; Scott A. Hughes

2014-07-25T23:59:59.000Z

14

Thermodynamics of the Three-dimensional Black Hole with a Coulomb-like Field

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.

Alexis Larranaga; Luz Angela Garcia

2008-11-20T23:59:59.000Z

15

We have investigated the dynamics of a neutral and a charged particle around a static and spherically symmetric black hole in the presence of quintessence matter and external magnetic field. We explore the conditions under which the particle moving around the black hole could escape to infinity after colliding with another particle. The innermost stable circular orbit (ISCO) for the particles are studied in detail. Mainly the dependence of ISCO on dark energy and on the presence of external magnetic field in the vicinity of black hole is discussed. By using the Lyapunov exponent, we compare the stabilities of the orbits of the particles in the presence and absence of dark energy and magnetic field. The expressions for the center of mass energies of the colliding particles near the horizon of the black hole are derived. The effective force on the particle due to dark energy and magnetic field in the vicinity of black hole is also discussed.

Mubasher Jamil; Saqib Hussain; Bushra Majeed

2014-04-28T23:59:59.000Z

16

Quasinormal frequencies of the Dirac field in a D-dimensional Lifshitz black hole

In a D-dimensional Lifshitz black hole we calculate exactly the quasinormal frequencies of a test Dirac field in the massless and zero angular eigenvalue limits. These results are an extension of the previous calculations in which the quasinormal frequencies of the Dirac field are determined, but in four dimensions. We discuss the four-dimensional limit of our expressions for the quasinormal frequencies and compare with the previous results. We also determine whether the Dirac field has unstable modes in the D-dimensional Lifshitz spacetime.

A. Lopez-Ortega

2014-07-03T23:59:59.000Z

17

String loops in the field of braneworld spherically symmetric black holes and naked singularities

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.

Stuchlík, Z.; Kološ, M., E-mail: zdenek.stuchlik@fpf.slu.cz, E-mail: martin.kolos@fpf.slu.cz [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezru?ovo nám.13, CZ-74601 Opava (Czech Republic)

2012-10-01T23:59:59.000Z

18

Absorption of a massive scalar field by a charged black hole

We calculate the absorption cross section of a massive neutral scalar field impinging upon a Reissner-Nordstr\\"om black hole. First, we derive key approximations in the high- and low-frequency regimes. Next, we develop a numerical method to compute the cross section at intermediate frequencies, and present a selection of results. Finally, we draw together our complementary approaches to give a quantitative full-spectrum description of absorption.

Carolina L. Benone; Ednilton S. de Oliveira; Sam R. Dolan; Luís C. B. Crispino

2014-04-02T23:59:59.000Z

19

Black hole in thermal equilibrium with a scalar field: The back-reaction

Science Journals Connector (OSTI)

The accurate approximation found by Page for the expectation value of the renormalized thermal equilibrium stress-energy tensor of a free conformal scalar field in a Schwarzschild black-hole background is used as the source in the semiclassical Einstein equation. The back-reaction and new equilibrium metric are found perturbatively in order ?. The new metric is not asymptotically flat unless the system is enclosed by a reflecting wall. Solutions are obtained for systems of finite radius using microcanonical (fixed energy) and canonical (fixed temperature) boundary conditions. Explicit effects of the back-reaction on the equilibrium temperature distribution inside the cavity are given. With microcanonical boundary conditions there is an asymptotically flat region where the temperature at infinity is defined. It is shown that this temperature does not have the Schwarzschild value ?(8?M)-1 for a black hole of mass M. Curvature invariants are computed and the order-?2 correction to the conformal scalar-field trace anomaly originating from the back-reaction that this field produces is found. The principal qualitative features of the results should be valid for any quantum field at one loop in the Schwarzschild geometry.

James W. York; Jr.

1985-02-15T23:59:59.000Z

20

Science Journals Connector (OSTI)

The properties of the electric field of a two-body system consisting of a Reissner-Nordström black hole and a charged massive particle at rest have recently been analyzed in the framework of first order perturbation theory following the standard approach of Regge, Wheeler, and Zerilli. In the present paper we complete this analysis by numerically constructing and discussing the lines of force of the “effective” electric field of the sole particle with the subtraction of the dominant contribution of the black hole. We also give the total field due to the black hole and the particle. As the black hole becomes extreme an effect analogous to the Meissner effect arises for the electric field, with the “effective field” lines of the point charge being expelled by the outer horizon of the black hole. This effect existing at the level of test field approximation, i.e. by neglecting the backreaction on the background metric and electromagnetic field due to the particle’s mass and charge, is here found also at the complete perturbative level. We point out analogies with similar considerations for magnetic fields by Bi?ák and Dvo?ák. We also explicitly show that the linearization of the recently obtained Belinski-Alekseev exact solution coincides with our solution in the Regge-Wheeler gauge. Our solution thus represents a bridge between the test field solution, which neglects all the feedback terms, and the exact two-body solution, which takes into account all the nonlinearity of the interaction.

D. Bini; A. Geralico; R. Ruffini

2008-03-17T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

21

Black hole with a Dirac field in 3+1 dimensions

We study a complex Dirac field in the quiral representation minimally coupled to gravity in 3+1 dimensions in the context of Einstein-Cartan theory. Generically the matter content gravitates in two different ways: On the one hand, the energy-momentum induces spacetime curvature; on the other hand, the presence of spin acts as a source for the spacetime torsion, which does not propagate. In this setup we consider the most general static spherically symmetric solution and we find an analytic black hole solution that supports a nontrivial spinor configuration. The sprinor field affects the geometry by inducing spacetime torsion, though, remarkably, it does not alter the black hole metric, which retains its Schwarzschild form. We find solutions both in asymptotically flat and asymptotically (Anti) de Sitter spaces. Additionally, we consider how the solution gets deformed when the so-called Holst term is included in the gravity action. We discuss possible observational effects due to the coupling of fermions in th...

Toloza, Adolfo

2014-01-01T23:59:59.000Z

22

Particle Dynamics around Riessner-Nordstr\\"om Black Hole with Magnetic Field

We investigate the dynamics of a neutral and a charged particle around the Reissner-Nordstr\\"om (RN) black hole immersed in magnetic field. We are interested to explore the conditions under which the moving charged particle can escape to infinity after collision with another neutral particle or a photon in the vicinity of the BH. We have calculated the expressions of the escape velocity. Further we have studied that how does the presence of magnetic field in the vicinity of BH, effect the motion of the orbiting particle. There are more than one stable regions if we consider the magnetic field in the accretion disk of BH so the stability of ISCO increases in the presence of magnetic field. We have also discussed the Lyapunov exponent in detail. Time-like geodesics of the moving particle are also studied. It is observed that the particle goes closer to the extremal RN-BH as compared to the case when it is moving around RN-BH.

Majeed, Bushra; Jamil, Mubasher

2014-01-01T23:59:59.000Z

23

Particle Dynamics around Riessner-Nordström Black Hole with Magnetic Field

We investigate the dynamics of a neutral and a charged particle around the Reissner-Nordstr\\"om (RN) black hole immersed in magnetic field. We are interested to explore the conditions under which the moving charged particle can escape to infinity after collision with another neutral particle or a photon in the vicinity of the BH. We have calculated the expressions of the escape velocity. Further we have studied that how does the presence of magnetic field in the vicinity of BH, effect the motion of the orbiting particle. There are more than one stable regions if we consider the magnetic field in the accretion disk of BH so the stability of ISCO increases in the presence of magnetic field. We have also discussed the Lyapunov exponent in detail. Time-like geodesics of the moving particle are also studied. It is observed that the particle goes closer to the extremal RN-BH as compared to the case when it is moving around RN-BH.

Bushra Majeed; Saqib Hussain; Mubasher Jamil

2014-11-18T23:59:59.000Z

24

The properties of the electric field of a two-body system consisting of a Reissner-Nordstr\\"om black hole and a charged massive particle at rest have recently been analyzed in the framework of first order perturbation theory following the standard approach of Regge, Wheeler and Zerilli. In the present paper we complete this analysis by numerically constructing and discussing the lines of force of the "effective" electric field of the sole particle with the subtraction of the dominant contribution of the black hole. We also give the total field due to the black hole and the particle. As the black hole becomes extreme an effect analogous to the Meissner effect arises for the electric field, with the "effective field" lines of the point charge being expelled by the outer horizon of the black hole. This effect existing at the level of test field approximation, i.e. by neglecting the backreaction on the background metric and electromagnetic field due to the particle's mass and charge, is here found also at the complete perturbative level. We point out analogies with similar considerations for magnetic fields by Bi{\\v c}\\'ak and Dvo{\\v r}\\'ak. We also explicitly show that the linearization of the recently obtained Belinski-Alekseev exact solution coincides with our solution in the Regge-Wheeler gauge. Our solution thus represents a "bridge" between the test field solution, which neglects all the feedback terms, and the exact two-body solution, which takes into account all the non-linearity of the interaction.

Donato Bini; Andrea Geralico; Remo Ruffini

2014-08-20T23:59:59.000Z

25

Greybody factors for brane scalar fields in a rotating black hole background

Science Journals Connector (OSTI)

We study the evaporation of (4+n)-dimensional rotating black holes into scalar degrees of freedom on the brane. We calculate the corresponding absorption probabilities and cross sections obtaining analytic solutions in the low-energy regime and compare the derived analytic expressions to numerical results, with very good agreement. We then consider the high-energy regime, construct an analytic high-energy solution to the scalar-field equation by employing a new method, and calculate the absorption probability and cross section for this energy regime, finding again a very good agreement with the exact numerical results. We also determine the high-energy asymptotic value of the total cross section and compare it to the analytic results derived from the application of the geometrical optics limit.

S. Creek, O. Efthimiou, P. Kanti, and K. Tamvakis

2007-04-30T23:59:59.000Z

26

Asymptotically locally AdS and asymptotically flat black hole solutions are found for a particular case of the Horndeski action. The action contains the Einstein-Hilbert term with a cosmological constant, a real scalar field with a non minimal kinetic coupling given by the Einstein tensor, the minimal kinetic coupling and the Maxwell term. There is no scalar potential. The solution has two integration constants related with the mass and the electric charge. The solution is given for all dimensions. A new class of asymptotically locally flat spherically symmetric black holes is found when the minimal kinetic coupling vanishes and the cosmological constant is present. In this case we get a solution which represents an electric Universe. The electric field at infinity is only supported by $\\Lambda$. When the cosmological constant vanishes the black hole is asymptotically flat.

Adolfo Cisterna; Cristián Erices

2014-03-03T23:59:59.000Z

27

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

Buratto, Steve

28

CONSTRAINTS ON THE VISCOSITY AND MAGNETIC FIELD IN HOT ACCRETION FLOWS AROUND BLACK HOLES

The magnitude of the viscosity and magnetic field parameters in hot accretion flows is investigated in low luminosity active galactic nuclei (LLAGNs). Theoretical studies show that a geometrically thin, optically thick disk is truncated at mass accretion rates less than a critical value by mass evaporated vertically from the disk to the corona, with the truncated region replaced by an advection dominated accretion flow (ADAF). The critical accretion rate for such a truncation is a function of the viscosity and magnetic field. Observations of X-ray photon indices and spectral fits of a number of LLAGNs published in the literature provide an estimate of the critical rate of mass accretion and the truncation radius, respectively. By comparing the observational results with theoretical predictions, the viscosity and magnetic field parameters in the hot accretion flow region are estimated. Specifically, the mass accretion rates inferred in different sources constrain the viscosity parameter, whereas the truncation radii of the disk, as inferred from spectral fits, further constrain the magnetic field parameter. It is found that the value of the viscosity parameter in the corona/ADAF ranges from 0.17 to 0.5, with values clustered about 0.2-0.3. Magnetic pressure is required by the relatively small truncation radii for some LLAGNs and is found to be as high as its equipartition value with the gas pressure. The inferred values of the viscosity parameter are in agreement with those obtained from the observations of non-stationary accretion in stellar mass black hole X-ray transients. This consistency provides support for the paradigm that a geometrically thin disk is truncated by means of a mass evaporation process from the disk to the corona at low mass accretion rates.

Liu, B. F. [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Taam, Ronald E., E-mail: bfliu@nao.cas.cn, E-mail: r-taam@northwestern.edu [Academia Sinica Institute of Astronomy and Astrophysics-TIARA, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2013-07-15T23:59:59.000Z

29

We study the acceleration of an electric current-carrying and axially-symmetric string loop initially oscillating in the vicinity of a Schwarzschild black hole embedded in an external asymptotically uniform magnetic field. The plane of the string loop is orthogonal to the magnetic field lines and the acceleration of the string loop occurs due to the transmutation effect turning in the deep gravitational field the internal energy of the oscillating strings to the energy of their translational motion along the axis given by the symmetry of the black hole spacetime and the magnetic field. We restrict our attention to the motion of string loop with energy high enough, when it can overcome the gravitational attraction and escape to infinity. We demonstrate that for the current-carrying string loop the transmutation effect is enhanced by the contribution of the interaction between the electric current of the string loop and the external magnetic field and we give conditions that have to be fulfilled for an efficient acceleration. The Schwarzschild black hole combined with the strong external magnetic field can accelerate the current-carrying string loop up to the velocities close to the speed of light $v \\sim c$. Therefore, the string loop transmutation effect can potentially well serve as an explanation for acceleration of highly relativistic jets observed in microquasars and active galactic nuclei.

Arman Tursunov; Martin Kološ; Zden?k Stuchlík; Bobomurat Ahmedov

2014-09-16T23:59:59.000Z

30

The Role of Magnetic Field Dissipation in the Black Hole Candidate Sgr A*

The compact, nonthermal radio source Sgr A* at the Galactic Center appears to be coincident with a 2.6 million solar mass point-like object. Its energy source may be the release of gravitational energy as gas from the interstellar medium descends into its potential well. Simple attempts at calculating the spectrum and flux based on this picture have come close to the observations, yet have had difficulty in accounting for the low efficiency in this source. There now appear to be two reasons for this low conversion rate: (1) the plasma separates into two temperatures, with the protons attaining a significantly higher temperature than that of the radiating electrons, and (2) the magnetic field, B, is sub-equipartition, which reduces the magnetic bremsstrahlung emissivity, and therefore the overall power of Sgr A*. We investigate the latter with improvement over what has been attempted before: rather than calculating B based on a presumed model, we instead infer its distribution with radius empirically with the requirement that the resulting spectrum matches the observations. Our ansatz for B(r) is motivated in part by earlier calculations of the expected magnetic dissipation rate due to reconnection in a compressed flow. We find reasonable agreement with the observed spectrum of Sgr A* as long as its distribution consists of 3 primary components: an outer equipartition field, a roughly constant field at intermediate radii (~1000 Schwarzschild radii), and an inner dynamo (more or less within the last stable orbit for a non-rotating black hole) which increases B to about 100 Gauss. The latter component accounts for the observed sub-millimiter hump in this source.

Robert F. Coker; Fulvio Melia

1999-09-24T23:59:59.000Z

31

General relativistic magnetohydrodynamic (GRMHD) flows along magnetic fields threading a black hole can be divided into inflow and outflow part, according to the result of the competition between the black hole gravity and magneto-centrifugal forces along the field line. Here we present the first self-consistent, semi-analytical solution for a cold, Poynting flux-dominated (PFD) GRMHD flow, which pass all four critical (inner and outer, Alfv\\'en and fast-magnetosonic) points along a parabolic streamline. By assuming that the dominating (electromagnetic) component of the energy flux per flux tube is conserved at the surface where the inflow and outflow are separated, the outflow part of the solution can be constraint by the inflow part of the solution.The semi-analytical method can provide fiducial and complementary solutions for GRMHD simulations around the rotating black hole, given that the black hole spin, global streamline, and magnetizaion (i.e., a mass-loading at the inflow/outflow separation) are presc...

Pu, Hung-Yi; Hirotani, Kouichi; Mizuno, Yosuke; Wu, Kinwah; Asada, Keiichi

2015-01-01T23:59:59.000Z

32

of high Al-content AlGaN quantum well lasers Jing Zhang, Hongping Zhao, and Nelson Tansu Citation: Appl of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content Al characteristics of high Al-content AlGaN quantum wells QWs are analyzed for deep UV lasers. The effect of crystal

Gilchrist, James F.

33

We study the acceleration of an electric current-carrying and axially-symmetric string loop initially oscillating in the vicinity of a Schwarzschild black hole embedded in an external asymptotically uniform magnetic field. The plane of the string loop is orthogonal to the magnetic field lines and the acceleration of the string loop occurs due to the transmutation effect turning in the deep gravitational field the internal energy of the oscillating strings to the energy of their translational motion along the axis given by the symmetry of the black hole spacetime and the magnetic field. We restrict our attention to the motion of string loop with energy high enough, when it can overcome the gravitational attraction and escape to infinity. We demonstrate that for the current-carrying string loop the transmutation effect is enhanced by the contribution of the interaction between the electric current of the string loop and the external magnetic field and we give conditions that have to be fulfilled for an efficien...

Tursunov, Arman; Stuchlík, Zden?k; Ahmedov, Bobomurat

2014-01-01T23:59:59.000Z

34

Solitons and black holes in a generalized Skyrme model with dilaton-quarkonium field

Skyrme theory is among the viable effective theories which emerge from the low-energy limit of quantum chromodynamics. Many of its generalizations include also a dilaton. Here we find new self-gravitating solutions, both solitons and black holes, in a generalized Skyrme model in which a dilaton is present. The investigation of the properties of the solutions is done numerically. We find that the introduction of the dilaton in the theory does not change the picture qualitatively, only quantitatively. The model considered here has one free parameter more than the Einstein-Skyrme model which comes from the potential of the dilaton. We have applied also the turning point method to establish that one of the black-hole branches of solutions is unstable. The turning point method here is based on the first law of black-hole thermodynamics a detailed derivation of which is given in the Appendix of the paper.

Doneva, Daniela D. [Deptartment of Astronomy, Faculty of Physics, St. Kliment Ohridski University of Sofia, 5, James Bourchier Blvd., 1164 Sofia (Bulgaria); Theoretical Astrophysics, Eberhard-Karls University of Tuebingen, Tuebingen 72076 (Germany); Stefanov, Ivan Zh. [Department of Applied Physics, Technical University of Sofia, 8, Kliment Ohridski Blvd., 1000 Sofia (Bulgaria); Yazadjiev, Stoytcho S. [Department of Theoretical Physics, Faculty of Physics, St. Kliment Ohridski University of Sofia, 5, James Bourchier Blvd., 1164 Sofia (Bulgaria)

2011-06-15T23:59:59.000Z

35

Thermodynamics of dual conformal field theories for Kerr-AdS black holes

Recently Gibbons et al. in [G. W. Gibbons et al. Class. Quant. Grav. 22, 1503 (2005)] defined a set of conserved quantities for Kerr-AdS black holes with the maximal number of rotation parameters in arbitrary dimension. This set of conserved quantities is defined with respect to a frame which is nonrotating at infinity. On the other hand, there is another set of conserved quantities for Kerr-AdS black holes, defined by Hawking et al. in [Hawking et al. Phys. Rev. D 59, 064005 (1999)], which is measured relative to a frame rotating at infinity. Gibbons et al. explicitly showed that the quantities defined by them satisfy the first law of black hole thermodynamics, while those quantities defined by Hawking et al. do not obey the first law. In this paper we discuss thermodynamics of dual CFTs to the Kerr-AdS black holes by mapping the bulk thermodynamic quantities to the boundary of the AdS space. We find that thermodynamic quantities of dual CFTs satisfy the first law of thermodynamics and Cardy-Verlinde formula only when these thermodynamic quantities result from the set of bulk quantities given by Hawking et al.. We discuss the implication of our results.

Cai Ronggen; Cao Liming; Pang Dawei [Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080 (China); Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)

2005-08-15T23:59:59.000Z

36

Probing strong-field gravity and black holes with gravitational waves

Gravitational wave observations will be excellent tools for making precise measurements of processes that occur in very strong- field regions of space time. Extreme mass

Hughes, Scott A.

37

Production and injection data from nine slim holes and sixteen large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan were analyzed in order to establish relationships (1) between injectivity and productivity indices, (2) between productivity/injectivity index and borehole diameter, and (3) between discharge capacity of slim holes and large-diameter wells. Results are compared with those from the Oguni and Sumikawa fields. A numerical simulator (WELBOR) was used to model the available discharge rate from Takigami boreholes. The results of numerical modeling indicate that the flow rate of large-diameter geothermal production wells with liquid feedzones can be predicted using data from slim holes. These results also indicate the importance of proper well design.

Garg, S.K. [Maxwell Federal Div., Inc., San Diego, CA (United States)] [Maxwell Federal Div., Inc., San Diego, CA (United States); Combs, J. [Geo-Hills Associates, Los Altos Hills, CA (United States)] [Geo-Hills Associates, Los Altos Hills, CA (United States); Azawa, Fumio [Idemitsu Kosan Co. Ltd., Tokyo (Japan)] [Idemitsu Kosan Co. Ltd., Tokyo (Japan); Gotoh, Hiroki [Idemitsu Oita Geothermal Co. Ltd., Oita (Japan)] [Idemitsu Oita Geothermal Co. Ltd., Oita (Japan)

1996-11-01T23:59:59.000Z

38

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.

Nicholas G Phillips; B. L. Hu

2002-09-17T23:59:59.000Z

39

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Black Holes at RHIC? Black Holes at RHIC? Further discussion by Physicist Dmitri Kharzeev on why RHIC cannot produce a real gravitational black hole Black holes are among the most mysterious objects in the universe. The gravitational field of a black hole is so strong that Einstein's general relativity tells us that nothing, not even light, can escape from the black hole's interior. However, in 1974 physicist Stephen Hawking demonstrated that black holes must emit radiation once the quantum effects are included. According to quantum mechanics, the physical vacuum is bubbling with short-lived virtual particle-antiparticle pairs. Creation of a particle-antiparticle pair from the vacuum conflicts with energy conservation, but energy need not be conserved at short times in quantum mechanics, according to Heisenberg's

40

Goshen, Utah: Energy Resources | Open Energy Information

9.9530088Â°, -111.9007716Â° 9.9530088Â°, -111.9007716Â° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":39.9530088,"lon":-111.9007716,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

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41

Goshen, Vermont: Energy Resources | Open Energy Information

495084Â°, -73.0220563Â° 495084Â°, -73.0220563Â° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":43.8495084,"lon":-73.0220563,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

42

Black hole Meissner effect and entanglement

Extremal black holes tend to expel magnetic and electric fields. Fields are unable to reach the horizon because the length of the black hole throat blows up in the extremal limit. The length of the throat is related to the ...

Penna, Robert

43

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A comparative study of the upper critical field Hc2 and second magnetization peak Hsp was performed using high-quality single crystals of hole-doped Ba0.68K0.32Fe2As2 and electron-doped BaFe1.85Co0.15As2 and BaFe1.91Ni0.09As2. The Hc2 was extracted from both resistivity and magnetization measurements using varying magnetic fields on H?c and H?c orientations. The anisotropic ratio, ?=Hc2?c/Hc2?c, was observed to decrease to ?2.5 for the hole-doped and ?3.0 for both electron-doped samples as the magnetic fields were increased up to 9 T. It demonstrates that the anisotropic properties only show slight change by doping aliovalent ions either in or out-of the basal plane of FeAs. For the hole-doped Ba0.68K0.32Fe2As2 the Hc2 and Hsp shift toward the higher temperature and higher field regime in the temperature-normalized (T/Tc) vortex phase diagram, suggesting a stronger vortex pinning by the comparison with the electron-doped BaFe1.85Co0.15As2 and BaFe1.91Ni0.09As2. In contrast to the As-deficiency or inhomogeneous doping distribution of K, Co, and Ni, the dense pinning centers in Ba0.68K0.32Fe2As2 may be attributed to the disordered structural domains and suggested to be responsible for the intrinsic disorder and anisotropy of iron arsenides.

D. L. Sun; Y. Liu; C. T. Lin

2009-10-12T23:59:59.000Z

44

Two techniques for computing black hole entropy in generally covariant gravity theories including arbitrary higher derivative interactions are studied. The techniques are Wald's Noether charge approach introduced recently, and a field redefinition method developed in this paper. Wald's results are extended by establishing that his local geometric expression for the black hole entropy gives the same result when evaluated on an arbitrary cross-section of a Killing horizon (rather than just the bifurcation surface). Further, we show that his expression for the entropy is not affected by ambiguities which arise in the Noether construction. Using the Noether charge expression, the entropy is evaluated explicitly for black holes in a wide class of generally covariant theories. Further, it is shown that the Killing horizon and surface gravity of a stationary black hole metric are invariant under field redefinitions of the metric of the form $\\bar{g}_{ab}\\equiv g_{ab} + \\Delta_{ab}$, where $\\Delta_{ab}$ is a tensor field constructed out of stationary fields. Using this result, a technique is developed for evaluating the black hole entropy in a given theory in terms of that of another theory related by field redefinitions. Remarkably, it is established that certain perturbative, first order, results obtained with this method are in fact {\\it exact}. The possible significance of these results for the problem of finding the statistical origin of black hole entropy is discussed.}

Ted Jacobson; Gungwon Kang; Robert C. Myers

1994-01-03T23:59:59.000Z

45

Science Journals Connector (OSTI)

Massive bosonic fields of arbitrary spin are predicted by general extensions of the standard model. It has been recently shown that there exists a family of bimetric theories of gravity—including massive gravity—which are free of Boulware-Deser ghosts at the nonlinear level. This opens up the possibility to describe consistently the dynamics of massive spin-2 particles in a gravitational field. Within this context, we develop the study of massive spin-2 fluctuations—including massive gravitons—around Schwarzschild and slowly rotating Kerr black holes. Our work has two important outcomes. First, we show that the Schwarzschild geometry is linearly unstable for small tensor masses, against a spherically symmetric mode. Second, we provide solid evidence that the Kerr geometry is also generically unstable, both against the spherical mode and against long-lived superradiant modes. In the absence of nonlinear effects, the observation of spinning black holes bounds the graviton mass ? to be ??5×10-23??eV.

Richard Brito; Vitor Cardoso; Paolo Pani

2013-07-10T23:59:59.000Z

46

Science Journals Connector (OSTI)

An analytical solution is presented for linear force fields within a spherical shell, representing the solar corona. Allowing for a global magnetic helicity, we find magnetic fields over the entire corona with...

J. R. Clegg; B. J. I. Bromage; P. K. Browning

47

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.

Renner, Joel Lawrence; Garg, Sabodh K.; Combs, Jim

2002-06-01T23:59:59.000Z

48

Optical black holes and solitons

We exhibit a static, cylindrically symmetric, exact solution to the Euler-Heisenberg field equations (EHFE) and prove that its effective geometry contains (optical) black holes. It is conjectured that there are also soliton solutions to the EHFE which contain black hole geometries.

Shawn Westmoreland

2010-12-21T23:59:59.000Z

49

Observations of gravitational systems agree well with the predictions of general relativity (GR); however, to date we have only tested gravity in the weak-field limit. In the next few years, observational advances may make ...

Vigeland, Sarah Jane

2012-01-01T23:59:59.000Z

50

Science Journals Connector (OSTI)

Energy spectra and spectrally resolved one-dimensional fluence images of self-emitted charged-fusion products (14.7 MeV D3He protons) are routinely measured from indirectly driven inertial-confinement fusion (ICF) experiments utilizing ignition-scaled hohlraums at the National Ignition Facility (NIF). A striking and consistent feature of these images is that the fluence of protons leaving the ICF target in the direction of the hohlraum's laser entrance holes (LEHs) is very nonuniform spatially, in contrast to the very uniform fluence of protons leaving through the hohlraum equator. In addition, the measured nonuniformities are unpredictable, and vary greatly from shot to shot. These observations were made separately at the times of shock flash and of compression burn, indicating that the asymmetry persists even at ~0.5–2.5 ns after the laser has turned off. These phenomena have also been observed in experiments on the OMEGA laser facility with energy-scaled hohlraums, suggesting that the underlying physics is similar. Comprehensive data sets provide compelling evidence that the nonuniformities result from proton deflections due to strong spontaneous electromagnetic fields around the hohlraum LEHs. Although it has not yet been possible to uniquely determine whether the fields are magnetic (B) or electric (E), preliminary analysis indicates that the strength is ~1 MG if B fields or ~109 V cm?1 if E fields. These measurements provide important physics insight into the ongoing ignition experiments at the NIF. Understanding the generation, evolution, interaction and dissipation of the self-generated fields may help to answer many physics questions, such as why the electron temperatures measured in the LEH region are anomalously large, and may help to validate hydrodynamic models of plasma dynamics prior to plasma stagnation in the center of the hohlraum.

C K Li; A B Zylstra; J A Frenje; F H Séguin; N Sinenian; R D Petrasso; P A Amendt; R Bionta; S Friedrich; G W Collins; E Dewald; T Döppner; S H Glenzer; D G Hicks; O L Landen; J D Kilkenny; A J Mackinnon; N Meezan; J Ralph; J R Rygg; J Kline; G Kyrala

2013-01-01T23:59:59.000Z

51

Signatures of black holes at the LHC

Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

Marco Cavaglia; Romulus Godang; Lucien M. Cremaldi; Donald J. Summers

2007-07-02T23:59:59.000Z

52

Small oscillations of current-carrying string loops around stable equilibrium positions corresponding to minima of the effective potential in the equatorial plane of the Kerr black holes are studied using the perturbation method. In the lowest approximation, two uncoupled harmonic oscillators are obtained that govern the radial and vertical oscillations; the higher-order terms determine non-linear phenomena and transition to chaotic motion through quasi-periodic stages of the oscillatory motion. The radial profiles of frequencies of the radial and vertical harmonic oscillations that are relevant also in the quasi-periodic stages of the oscillatory motion are given, and their properties in dependence on the spin of the black holes and the angular momentum and tension of the string loops are determined. It is shown that the radial profiles differ substantially from those corresponding to the radial and vertical frequencies of the geodetical epicyclic motion; however, they have the same mass-scaling and their magnitude is of the same order. Therefore, we are able to demonstrate that assuming relevance of resonant phenomena of the radial and vertical string-loop oscillations at their frequency ratio 3:2, the oscillatory frequencies of string loops can be well related to the frequencies of the twin high-frequency quasi-periodic oscillations (HF QPOs) observed in the microquasars GRS 1915+105, XTE 1550-564, GRO 1655-40. We can conclude that oscillating current-carrying string loops have to be considered as one of the possible explanations of the HF QPOs occurring in the field of compact objects.

Zden?k Stuchlík; Martin Kološ

2014-03-11T23:59:59.000Z

53

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.

G. 't Hooft

2005-04-25T23:59:59.000Z

54

White holes and eternal black holes

We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi- thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal.

Stephen D. H. Hsu

2011-11-16T23:59:59.000Z

55

Absorption cross section of RN black hole

The behavior of a charged scalar field in the RN black hole space time is studied using WKB approximation. In the present work it is assumed that matter waves can get reflected from the event horizon. Using this effect, the Hawking temperature and the absorption cross section for RN black hole placed in a charged scalar field are calculated. The absorption cross section $\\sigma _{abs}$ is found to be inversely proportional to square of the Hawking temperature of the black hole.

Sini R.; V. C. Kuriakose

2007-08-23T23:59:59.000Z

56

Black holes cannot support conformal scalar hair

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.

T. Zannias

1994-09-14T23:59:59.000Z

57

Science Journals Connector (OSTI)

High frequency dispersion does not alter the low frequency spectrum of Hawking radiation from a single black hole horizon, whether the dispersion entails subluminal or superluminal group velocities. We show here that in the presence of an inner horizon as well as an outer horizon the superluminal case differs dramatically however. The negative energy partners of Hawking quanta return to the outer horizon and stimulate more Hawking radiation if the field is bosonic or suppress it if the field is fermionic. This process leads to exponential growth or damping of the radiated flux and correlations among the quanta emitted at different times, unlike in the usual Hawking effect. These phenomena may be observable in condensed matter black hole analogues that exhibit “superluminal” dispersion.

Steven Corley and Ted Jacobson

1999-05-17T23:59:59.000Z

58

National Nuclear Security Administration (NNSA)

9%2A en Ten-Year Site Plans (TYSP) http:nnsa.energy.govaboutusouroperationsinfopsinfopstysp

field field-type-text field-field-page-name">

59

Thermodynamics of dilaton-axion black holes

Considering a generalized action for the Einstein-Maxwell theory in four dimensions coupled to scalar and pseudoscalar fields, the thermodynamic properties of asymptotically flat black hole solutions in such a background are investigated. Bekenstein-Hawking area-entropy law is verified for these class of black holes. From the property of specific heat, it is shown that such black holes can be stable for a certain choice of the parameters like charge, mass, and the scalar vacuum expectation value. The possibility of a black hole phase transition is discussed in this context.

Ghosh, Tanwi; SenGupta, Soumitra [Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Calcutta-700 032 (India)

2008-12-15T23:59:59.000Z

60

Black Holes: from Speculations to Observations

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.

Thomas W. Baumgarte

2006-04-13T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

61

Colorful quantum black holes at the LHC

We examine the LHC phenomenology of quantum black holes in models of TeV gravity. By quantum black holes we mean black holes of the smallest masses and entropies, far from the semiclassical regime. These black holes are formed and decay over short distances, and typically carry SU(3) color charges inherited from their parton progenitors. Based on a few minimal assumptions, such as gauge invariance, we identify interesting signatures for quantum black hole decay such as 2 jets, jet + hard photon, jet + missing energy and jet + charged lepton, which should be readily visible above background. The detailed phenomenology depends heavily on whether one requires a Lorentz invariant, low-energy effective field theory description of black hole processes.

Xavier Calmet; Wei Gong; Stephen D. H. Hsu

2008-06-27T23:59:59.000Z

62

Small oscillations of current-carrying string loops around stable equilibrium positions corresponding to minima of the effective potential in the equatorial plane of the Kerr black holes are studied using the perturbation method. In the lowest approximation, two uncoupled harmonic oscillators are obtained that govern the radial and vertical oscillations; the higher-order terms determine non-linear phenomena and transition to chaotic motion through quasi-periodic stages of the oscillatory motion. The radial profiles of frequencies of the radial and vertical harmonic oscillations that are relevant also in the quasi-periodic stages of the oscillatory motion are given, and their properties in dependence on the spin of the black holes and the angular momentum and tension of the string loops are determined. It is shown that the radial profiles differ substantially from those corresponding to the radial and vertical frequencies of the geodetical epicyclic motion; however, they have the same mass-scaling and their ma...

Stuchlík, Zden?k

2014-01-01T23:59:59.000Z

63

Particles and scalar waves in noncommutative charged black hole spacetime

In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately. A comparative study of noncommutative charged black hole and usual Reissner-Nordstrom black hole has been done. The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.

Bhar, Piyali; Biswas, Ritabrata; Mondal, U F

2015-01-01T23:59:59.000Z

64

Science Journals Connector (OSTI)

We studied the evolution of the photoluminescence (PL) spectra in modulation-doped GaAs-based heterostructures (single quantum wells and heterojunctions) at TL=1.2K under a high magnetic field B (up to 33T), which was applied parallel to the two-dimensional electron gas (2DEG) layer. Under low in-plane fields, B?<7T, the radiative recombination of the photoexcited hole with the 2DEG gives rise to a broad PL band that shifts quadratically with B?. This band transforms into a narrow PL line whose peak energy E shifts linearly with B? in the range of 10–33T. The slope of the linear E(B) dependence was measured as ?ex=0.77±0.02meV?T in all the studied structures. The same linear slope is also measured in the PL spectra of bulk, undoped GaAs under high B. We thus attribute the sharp PL line observed in the doped heterostructures to magnetoexcitons that are photogenerated outside the 2DEG layer by a geminate formation process. The slope of the magnetoexciton energy dependence on B? is compared with that measured for unbound-electron–hole Landau level transitions under a perpendicular B?. The ratio of the measured slopes, ?ex??0?0.8, is found to be equal to the ratio of the reduced excitonic mass to the reduced cyclotron mass of GaAs.

B. M. Ashkinadze, E. Cohen, V. V. Rudenkov, P. C. M. Christianen, J. C. Maan, and L. N. Pfeiffer

2007-08-27T23:59:59.000Z

65

Black Hole Horizons and Black Hole Thermodynamics.

??This work investigates how black holes can be described in terms of different definitions of horizons. Global definitions in terms of event horizons and Killing… (more)

Nielsen, Alex

2007-01-01T23:59:59.000Z

66

Black Hole Superradiance in Dynamical Spacetime

We study the superradiant scattering of gravitational waves by a nearly extremal black hole (dimensionless spin $a=0.99$) by numerically solving the full Einstein field equations, thus including backreaction effects. This allows us to study the dynamics of the black hole as it loses energy and angular momentum during the scattering process. To explore the nonlinear phase of the interaction, we consider gravitational wave packets with initial energies up to $10%$ of the mass of the black hole. We find that as the incident wave energy increases, the amplification of the scattered waves, as well as the energy extraction efficiency from the black hole, is reduced. During the interaction the apparent horizon geometry undergoes sizable nonaxisymmetric oscillations. The largest amplitude excitations occur when the peak frequency of the incident wave packet is above where superradiance occurs, but close to the dominant quasinormal mode frequency of the black hole.

William E. East; Fethi M. Ramazano?lu; Frans Pretorius

2014-03-14T23:59:59.000Z

67

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.

Hickox, Ryan C.; Alexander, David M.; Goulding, Andrew D. [Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom); Myers, Adam D. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Brodwin, Mark; Forman, William R.; Jones, Christine; Murray, Stephen S.; Eisenstein, Daniel; Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Brown, Michael J. I. [School of Physics, Monash University, Clayton 3800, Victoria (Australia); Cool, Richard J. [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States); Kochanek, Christopher S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Dey, Arjun; Jannuzi, Buell T. [National Optical Astronomy Observatory, Tucson, AZ 85726 (United States); Assef, Roberto J.; Eisenhardt, Peter R.; Gorjian, Varoujan; Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Le Floc'h, Emeric, E-mail: ryan.hickox@durham.ac.uk. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Universite Paris Diderot, CE-Saclay, pt courrier 131, 91191 Gif-sur-Yvette (France)

2011-04-20T23:59:59.000Z

68

Light-harvesting (LH) complexes of cyclic (C{sub n}) symmetry from photosynthetic bacteria are studied using absorption and high pressure- and Stark-hole burning spectroscopies. The B800 absorption band of LH2 is inhomogeneously broadened while the B850 band of LH2 and the B875 band of the LH1 complex exhibit significant homogeneous broadening due to ultra-fast inter-exciton level relaxation. The B800{r_arrow}B850 energy transfer rate of ({approximately}2 ps){sup {minus}1} as determined by hole burning and femtosecond pump-probe spectroscopies, is weakly dependent on pressure and temperature, both of which significantly affect the B800-B850 energy gap. The resilience is theoretically explained in terms of a modified Foerster theory with the spectral overlap provided by the B800 fluorescence origin band and weak vibronic absorption bands of B850. Possible explanations for the additional sub-picosecond relaxation channel of B800 observed with excitation on the blue side of B800 are given. Data from pressure and temperature dependent studies show that the B800 and B850 bacteriochlorophyll a (BChl a) molecules are weakly and strongly excitonically coupled, respectively, which is consistent with the X-ray structure of LH2. The B875 BChl a molecules are also strongly coupled. It is concluded that electron-exchange, in addition to electrostatic interactions, is important for understanding the strong coupling of the B850 and B875 rings. The large linear pressure shifts of {approximately}{minus}0.6 cm{sup {minus}1}/MPa associated with B850 and B875 can serve as important benchmarks for electronic structure calculations.

Wu, H.M.

1999-02-12T23:59:59.000Z

69

Geodesics and Geodesic Deviation in static Charged Black Holes

The radial motion along null geodesics in static charged black hole space-times, in particular, the Reissner-Nordstr\\"om and stringy charged black holes are studied. We analyzed the properties of the effective potential. The circular photon orbits in these space-times are investigated. We found that the radius of circular photon orbits in both charged black holes are different and differ from that given in Schwarzschild space-time. We studied the physical effects of the gravitational field between two test particles in stringy charged black hole and compared the results with that given in Schwarzschild and Reissner-Nordstr\\"om black holes.

Ragab M. Gad

2010-03-03T23:59:59.000Z

70

Spectral line broadening in magnetized black holes

We consider weakly magnetized non-rotating black holes. In the presence of a regular magnetic field the motion of charged particles in the vicinity of a black hole is modified. As a result, the position of the innermost stable circular orbit (ISCO) becomes closer to the horizon. When the Lorentz force is repulsive (directed from the black hole) the ISCO radius can reach the gravitational radius. In the process of accretion charged particles (ions) of the accreting matter can be accumulated near their ISCO, while neutral particles fall down to the black hole after they reach $6M$ radius. The sharp spectral line Fe K$\\alpha$, emitted by iron ions at such orbits, is broadened when the emission is registered by a distant observer. In this paper we study this broadening effect and discuss how one can extract information concerning the strength of the magnetic field from the observed spectrum.

Valeri P. Frolov; Andrey A. Shoom; Christos Tzounis

2014-05-02T23:59:59.000Z

71

Chaotic string-capture by black hole

Science Journals Connector (OSTI)

We consider a macroscopic charge-current carrying (cosmic) string in the background of a Schwarzschild black hole. The string is taken to be circular and is allowed to oscillate and to propagate in the direction perpendicular to its plane (that is parallel to the equatorial plane of the black hole). Numerical investigations indicate that the system is non-integrable, but the interaction with the gravitational field of the black hole still gives rise to various qualitatively simple processes like `adiabatic capture' and `string transmutation'.

A L Larsen

1994-01-01T23:59:59.000Z

72

The mass of a black hole has traditionally been identified with its energy. We describe a new perspective on black hole thermodynamics, one that identifies the mass of a black hole with chemical enthalpy, and the cosmological constant as thermodynamic pressure. This leads to an understanding of black holes from the viewpoint of chemistry, in terms of concepts such as Van der Waals fluids, reentrant phase transitions, and triple points. Both charged and rotating black holes exhibit novel chemical-type phase behaviour, hitherto unseen.

David Kubiznak; Robert B. Mann

2014-04-08T23:59:59.000Z

73

Black holes and thermodynamics

Science Journals Connector (OSTI)

A black hole of given mass, angular momentum, and charge can have a large number of different unobservable internal configurations which reflect the possible different initial configurations of the matter which collapsed to produce the hole. The logarithm of this number can be regarded as the entropy of the black hole and is a measure of the amount of information about the initial state which was lost in the formation of the black hole. If one makes the hypothesis that the entropy is finite, one can deduce that the black holes must emit thermal radiation at some nonzero temperature. Conversely, the recently derived quantum-mechanical result that black holes do emit thermal radiation at temperature ??2? k c, where ? is the surface gravity, enables one to prove that the entropy is finite and is equal to c3A4 G?, where A is the surface area of the event horizon or boundary of the black hole. Because black holes have negative specific heat, they cannot be in stable thermal equilibrium except when the additional energy available is less than 1/4 the mass of the black hole. This means that the standard statistical-mechanical canonical ensemble cannot be applied when gravitational interactions are important. Black holes behave in a completely random and time-symmetric way and are indistinguishable, for an external observer, from white holes. The irreversibility that appears in the classical limit is merely a statistical effect.

S. W. Hawking

1976-01-15T23:59:59.000Z

74

A toroidal black hole for the AGN phenomenon

A new approach to the study of the AGN phenomenon is proposed, in which the nucleus activity is related to the metric of the inner massive black hole. The possibility of a Toroidal Black Hole (TBH), in contrast to the usual Spherical Black Hole (SBH), is discussed as a powerful tool in understanding AGN related phenomena, such as the energetics, the production of jets and the acceleration of particles, the shape of the magnetic field and the lifetime of nucleus activity.

Fulvio Pompilio; S. M. Harun-or-Rashid; Matts Roos

2000-08-30T23:59:59.000Z

75

A Quantum Material Model of Static Schwarzschild Black Holes

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.

S. -T. Sung

1997-03-16T23:59:59.000Z

76

Uniformly accelerated black holes

Science Journals Connector (OSTI)

The static and stationary C metric are examined in a generic framework and their interpretations studied in some detail, especially those with two event horizons, one for the black hole and another for the acceleration. We find that (i) the spacetime of an accelerated static black hole is plagued by either conical singularities or a lack of smoothness and compactness of the black hole horizon, (ii) by using standard black hole thermodynamics we show that accelerated black holes have a higher Hawking temperature than Unruh temperature of the accelerated frame, and (iii) the usual upper bound on the product of the mass and acceleration parameters (<1/27) is just a coordinate artifact. The main results are extended to accelerated rotating black holes with no significant changes.

Patricio S. Letelier and Samuel R. Oliveira

2001-08-24T23:59:59.000Z

77

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.

Begelman, Mitchell C

2014-01-01T23:59:59.000Z

78

Primordial Black Hole Evolution in Tensor-Scalar Cosmology

Science Journals Connector (OSTI)

A perturbative analysis shows that black holes do not remember the value of the scalar field ? at the time they formed if ? changes in tensor-scalar cosmology. Moreover, even when the black hole mass in the Einstein frame is approximately unaffected by the changing of ?, in the Jordan-Fierz frame the mass increases. This mass increase requires a reanalysis of the evaporation of primordial black holes in tensor-scalar cosmology. It also implies that there could have been a significant magnification of the (Jordan-Fierz frame) mass of primordial black holes.

Ted Jacobson

1999-10-04T23:59:59.000Z

79

Absorption of scalars by extremal black holes in string theory

We show that the low frequency absorption cross section of minimally coupled massless scalar fields by extremal spherically symmetric black holes in d dimensions in the presence of string-theoretical alpha' corrections is equal to the horizon area. Classically one has the relation sigma=4GS between the absorption cross section and the black hole entropy. We discuss the validity of such relation in the presence of alpha' corrections for extremal black holes, both nonsupersymmetric and supersymmetric. The examples we consider seem to indicate that this relation is verified in the presence of alpha' corrections for supersymmetric black holes, but not for nonsupersymmetric ones.

Filipe Moura

2014-06-13T23:59:59.000Z

80

Entanglement entropy of black holes

The entanglement entropy is a fundamental quantity which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff which regulates the short-distance correlations. The geometrical nature of the entanglement entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in 4 and 6 dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as 't Hooft's brick wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields which non-minimally couple to gravity is emphasized. The holographic description of the entanglement entropy of the black hole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

Sergey N. Solodukhin

2011-04-19T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

81

Solar Wind Forecasting with Coronal Holes

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.

S. Robbins; C. J. Henney; J. W. Harvey

2007-01-09T23:59:59.000Z

82

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.

Valeri P. Frolov; Andrei V. Frolov

2014-12-30T23:59:59.000Z

83

We study the Hawking process on lattices falling into static black holes. The motivation is to understand how the outgoing modes and Hawking radiation can arise in a setting with a strict short distance cutoff in the free-fall frame. We employ two-dimensional free scalar field theory. For a falling lattice with a discrete time-translation symmetry we use analytical methods to establish that, for Killing frequency $\\omega$ and surface gravity $\\kappa$ satisfying $\\kappa\\ll\\omega^{1/3}\\ll 1$ in lattice units, the continuum Hawking spectrum is recovered. The low frequency outgoing modes arise from exotic ingoing modes with large proper wavevectors that "refract" off the horizon. In this model with time translation symmetry the proper lattice spacing goes to zero at spatial infinity. We also consider instead falling lattices whose proper lattice spacing is constant at infinity and therefore grows with time at any finite radius. This violation of time translation symmetry is visible only at wavelengths comparable to the lattice spacing, and it is responsible for transmuting ingoing high Killing frequency modes into low frequency outgoing modes.

Steven Corley; Ted Jacobson

1998-03-26T23:59:59.000Z

84

Absorption of planar massless scalar waves by Bardeen regular black holes

Accretion of fields by black holes is a subject of great interest in physics. It is known that accretion plays a fundamental role in active galactic nuclei and in the evolution of black holes. Accretion of fundamental fields is often related to the study of absorption cross section. Basically all black holes for which absorption of fields has been studied so far present singularities. However, even within general relativity, it is possible to construct regular black holes: objects with event horizons but without singularities. Many physically motivated regular black hole solutions have been proposed in the past years, demanding the understanding of their absorption properties. We study the absorption of planar massless scalar waves by Bardeen regular black holes. We compare the absorption cross section of Bardeen and Reissner--Nordstr\\"om black holes, showing that the former always have a bigger absorption cross section for fixed values of the field frequency and of the normalized black hole charge. We also show that it is possible for a Bardeen black hole to have the same high-frequency absorption cross section of a Reissner--Nordstr\\"om black hole. Our results suggest that, in mid-to-high-frequency regimes, regular black holes can have compatible properties with black holes with singularities, as far as absorption is concerned.

Caio F. B. Macedo; Luís C. B. Crispino

2014-08-08T23:59:59.000Z

85

Optical transitions of holes in uniaxially compressed germanium

Spontaneous emission and photoconductivity of germanium with gallium impurity are studied for determining the energy spectrum of hole states in this material in which radiation can be induced as a result of transitions of holes between these states. Holes were excited by electric field pulses with a strength up to 12 kV/cm at T = 4.2 K under uniaxial compression of samples up to 12 kbar. It has been found that hole emission spectra for transitions between resonant and local states of the impurity have a structure identical to the photoconductivity and absorption spectra. Transitions from resonance states, which are associated with the heavy hole subband, have not been detected. It has been found that in an electric field lower than 100 V/cm, a compressed crystal emits as a result of transitions of heavy holes. In a strong electric field (1-3 kV/cm), emission is observed in the energy range up to 140 meV, and transitions with emission of TA and LO phonons appear in such a field. The emission spectra under pressures of 0 and 12 kbar differ insignificantly. Hence, it follows that the contributions from heavy and light holes in a strong electric field are indistinguishable.

Pokrovskii, Ya. E., E-mail: yaep@cplire.ru; Khvalkovskii, N. A. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)] [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)

2013-10-15T23:59:59.000Z

86

As of October 2001, approximately 7,000 yd{sup 3} of stockpiled soil remained at Brookhaven National Laboratory (BNL) after the remediation of the BNL Chemical/Animal/Glass Pits disposal area. The soils were originally contaminated with radioactive materials and heavy metals, depending on what materials had been interred in the pits, and how the pits were excavated. During the 1997 removal action, the more hazardous/radioactive materials were segregated, along with, chemical liquids and solids, animal carcasses, intact gas cylinders, and a large quantity of metal and glass debris. Nearly all of these materials have been disposed of. In order to ensure that all debris was removed and to characterize the large quantity of heterogeneous soil, BNL initiated an extended sorting, segregation, and characterization project directed at the remaining soil stockpiles. The project was co-funded by the Department of Energy Environmental Management Office (DOE EM) through the BNL Environmental Restoration program and through the DOE EM Office of Science and Technology Accelerated Site Technology Deployment (ASTD) program. The focus was to remove any non-conforming items, and to assure that mercury and radioactive contaminant levels were within acceptable limits for disposal as low-level radioactive waste. Soils with mercury concentrations above allowable levels would be separated for disposal as mixed waste. Sorting and segregation were conducted simultaneously. Large stockpiles (ranging from 150 to 1,200 yd{sup 3}) were subdivided into manageable 20 yd{sup 3} units after powered vibratory screening. The 1/2-inch screen removed almost all non-conforming items (plus some gravel). Non-conforming items were separated for further characterization. Soil that passed through the screen was also visually inspected before being moved to a 20 yd{sup 3} ''subpile.'' Eight samples from each subpile were collected after establishing a grid of four quadrants: north, east, south and west, and two layers: top and bottom. Field personnel collected eight 100-gram samples, plus quality assurance (QA) duplicates for chemical analysis, and a 1-liter jar of material for gamma spectroscopy. After analyses were completed and reviewed, the stockpiles were reconstructed for later disposal as discrete entities within a disposal site profile. A field lab was set up in a trailer close to the stockpile site, equipped with instrumentation to test for mercury, RCRA metals, and gamma spectroscopy, and a tumbler for carrying out a modified Toxicity Characteristic Leaching Procedure (TCLP) protocol. Chemical analysis included X-ray fluorescence (XRF) to screen for high (>260 ppm) total mercury concentrations, and modified TCLP tests to verify that the soils were not RCRA hazardous. The modified TCLP tests were 1/10th scale, to minimize secondary (leachate) waste and maximize tumbler capacity and sampler throughput. TCLP leachate analysis was accomplished using a Milestone Direct Mercury Analyzer (DMA80). Gamma spectroscopy provided added assurance of previously measured Am-241, Cs-137, and Co-60 contamination levels.

BOWERMAN,B.S.; ADAMS,J.W.; HEISER,J.; KALB,P.D.; LOCKWOOD,A.

2003-04-01T23:59:59.000Z

87

We trace the origin of the black hole entropy S, replacing a black hole by a quasiblack hole. Let the boundary of a static body approach its own gravitational radius, in such a way that a quasihorizon forms. We show that if the body is thermal with the temperature taking the Hawking value at the quasihorizon limit, it follows, in the nonextremal case, from the first law of thermodynamics that the entropy approaches the Bekenstein-Hawking value S=A/4. In this setup, the key role is played by the surface stresses on the quasihorizon and one finds that the entropy comes from the quasihorizon surface. Any distribution of matter inside the surface leads to the same universal value for the entropy in the quasihorizon limit. This can be of some help in the understanding of black hole entropy. Other similarities between black holes and quasiblack holes such as the mass formulas for both objects had been found previously. We also discuss the entropy for extremal quasiblack holes, a more subtle issue.

Lemos, Jose P. S.; Zaslavskii, Oleg B. [Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico-IST, Universidade Tecnica de Lisboa-UTL, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Astronomical Institute of Kharkov, V. N. Karazin National University, 35 Sumskaya Street, Kharkov, 61022 (Ukraine)

2010-03-15T23:59:59.000Z

88

Applying multiwell normalization in open hole log analysis

A major problem when analyzing open hole well logging data in large fields is the fact that the logs were run using different logging service companies, using different logging tools over a long time span. To obtain correct log interpretations...

Sinanan, Haydn Brent

2012-06-07T23:59:59.000Z

89

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Black Holes at RHIC? Black Holes at RHIC? Before RHIC began operations in 2000, some were concerned that it would produce black holes that would threaten the earth. Here's why those concerns were unfounded. Committee Review of Speculative "Disaster Scenarios" at RHIC In July 1999, Brookhaven Lab Director John Marburger convened a committee of distinguished physicists to write a comprehensive report on the arguments that address the safety of speculative disaster scenarios at RHIC. The scenarios are: Creation of a black hole that would "eat" ordinary matter. Initiation of a transition to a new, more stable universe. Formation of a "strangelet" that would convert ordinary matter to a new form. jaffee "We conclude that there are no credible mechanisms for catastrophic

90

Charged Schrodinger black holes

We construct charged and rotating asymptotically Schrödinger black hole solutions of type IIB supergravity. We begin by obtaining a closed-form expression for the null Melvin twist of a broad class of type IIB backgrounds, ...

Adams, Allan

91

The decay of an atom in the presence of a static perturbation is investigated. The perturbation couples a decaying state with a nondecaying state. A "hole" appears in the emission line at a frequency equal to the frequency ...

Fontana, Peter R.; Srivastava, Rajendra P.

1973-06-01T23:59:59.000Z

92

Schwarzschild black hole in dark energy background

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.

Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh

2014-09-27T23:59:59.000Z

93

Hydrodynamic model for electron-hole plasma in graphene

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.

D. Svintsov; V. Vyurkov; S. Yurchenko; T. Otsuji; V. Ryzhii

2012-01-03T23:59:59.000Z

94

Thermal Gradient Holes | Open Energy Information

Thermal Gradient Holes Thermal Gradient Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Thermal Gradient Holes Details Activities (50) Areas (39) Regions (4) NEPA(29) Exploration Technique Information Exploration Group: Drilling Techniques Exploration Sub Group: Exploration Drilling Parent Exploration Technique: Exploration Drilling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Field wide fluid flow characteristics if an array of wells are drilled Thermal: Mapping and projecting thermal anomalies Cost Information Low-End Estimate (USD): 5.00500 centUSD 0.005 kUSD 5.0e-6 MUSD 5.0e-9 TUSD / foot Median Estimate (USD): 16.501,650 centUSD 0.0165 kUSD 1.65e-5 MUSD 1.65e-8 TUSD / foot High-End Estimate (USD): 50.005,000 centUSD

95

Core Holes | Open Energy Information

Core Holes Core Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Core Holes Details Activities (8) Areas (7) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Drilling Techniques Exploration Sub Group: Exploration Drilling Parent Exploration Technique: Exploration Drilling Information Provided by Technique Lithology: Core holes are drilled to identify lithology and mineralization Stratigraphic/Structural: Retrieved samples can be used to identify fracture networks or faults Hydrological: Thermal: Thermal conductivity measurements can be done on retrieved samples. Dictionary.png Core Holes: A core hole is a well that is drilled using a hallow drill bit coated with synthetic diamonds for the purposes of extracting whole rock samples from

96

ar X iv :h ep -p h/ 05 11 12 8v 3 6 A pr 2 00 6 Black Holes at Accelerators Bryan Webber Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK In theories with large extra dimensions and TeV-scale gravity, black holes... 2000 3000 Missing ET (GeV) Ar bi tra ry S ca le p p ? QCD SUSY 5 TeV BH (n=6) 5 TeV BH (n=2) (PT > 600 GeV) (SUGRA point 5) Figure 10: Missing transverse energy for various processes at the LHC. 4.2. Event Characteristics Turning from single...

Webber, Bryan R

97

Scalar emission in a rotating Gödel black hole

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.

Songbai Chen; Bin Wang; Jiliang Jing

2008-08-23T23:59:59.000Z

98

Science Journals Connector (OSTI)

... interior. These models reveal several significantly different behaviours. The simplest model, of a 'Schwarzschild' black hole, which possesses mass but no charge or angular momentum, has an ... into account, seal off the 'tunnel', and yield an interior similar to the Schwarzschild model, with an all-encompassing crushing singularity. More recently, there have been attempts6- ...

William A. Hiscock

1991-10-24T23:59:59.000Z

99

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.

Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

2014-01-14T23:59:59.000Z

100

Black holes and structure in an oscillating universe

Science Journals Connector (OSTI)

... a = 27 irG2 M2 / c4 is the radiation capture cross-section for a Schwarzschild black hole. This assumes that black holes accrete independently in a uniform radiation field ... cm and rA = (81/64)c?1r0>Sch s where rOSch is the initial Schwarzschild radius (c.g.s. units). Thus A?1016cm, corresponding to rA?10? ...

William C. Saslaw

1991-03-07T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

101

Electromagnetic wave scattering by Schwarzschild black holes

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.

Luís C. B. Crispino; Sam R. Dolan; Ednilton S. Oliveira

2009-05-20T23:59:59.000Z

102

Black hole entanglement entropy and the renormalization group

Science Journals Connector (OSTI)

We investigate the contributions of quantum fields to black hole entropy by using a cutoff scale at which the theory is described with a Wilsonian effective action. For both free and interacting fields, the total black hole entropy can be partitioned into a contribution derived from the gravitational effective action and a contribution from quantum fluctuations below the cutoff scale. In general, the latter includes a quantum contribution to the Noether charge. We analyze whether it is appropriate to identify the rest with horizon entanglement entropy, and find several complications for this interpretation, which are especially problematic for interacting fields.

Ted Jacobson and Alejandro Satz

2013-04-18T23:59:59.000Z

103

Black hole entanglement entropy and the renormalization group

We investigate the contributions of quantum fields to black hole entropy by using a cutoff scale at which the theory is described with a Wilsonian effective action. For both free and interacting fields, the total black hole entropy can be partitioned into a contribution derived from the gravitational effective action and a contribution from quantum fluctuations below the cutoff scale. In general the latter includes a quantum contribution to the Noether charge. We analyze whether it is appropriate to identify the rest with horizon entanglement entropy, and find several complications for this interpretation, which are especially problematic for interacting fields.

Ted Jacobson; Alejandro Satz

2013-03-21T23:59:59.000Z

104

Comparing quantum black holes and naked singularities

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.

T. P. Singh

2000-12-21T23:59:59.000Z

105

Supermassive black holes have generally been recognized as the most destructive force in nature. But in recent years, they have undergone a dramatic shift in paradigm. These objects may have been critical to the formation of structure in the early universe, spawning bursts of star formation and nucleating proto-galactic condensations. Possibly half of all the radiation produced after the Big Bang may be attributed to them, whose number is now known to exceed 300 million. The most accessible among them is situated at the Center of Our Galaxy. In the following pages, we will examine the evidence that has brought us to this point, and we will understand why many expect to actually image the event horizon of the Galaxy's central black hole within this decade.

Fulvio Melia

2007-05-10T23:59:59.000Z

106

Gauss-Bonnet black holes in dS spaces

Science Journals Connector (OSTI)

We study the thermodynamic properties associated with the black hole horizon and cosmological horizon for the Gauss-Bonnet solution in de Sitter space. When the Gauss-Bonnet coefficient is positive, a locally stable small black hole appears in the case of spacetime dimension d=5, the stable small black hole disappears, and the Gauss-Bonnet black hole is always unstable quantum mechanically when d>~6. On the other hand, the cosmological horizon is found to be always locally stable independent of the spacetime dimension. But the solution is not globally preferred; instead, the pure de Sitter space is globally preferred. When the Gauss-Bonnet coefficient is negative, there is a constraint on the value of the coefficient, beyond which the gravity theory is not well defined. As a result, there is not only an upper bound on the size of black hole horizon radius at which the black hole horizon and cosmological horizon coincide with each other, but also a lower bound depending on the Gauss-Bonnet coefficient and spacetime dimension. Within the physical phase space, the black hole horizon is always thermodynamically unstable and the cosmological horizon is always stable; furthermore, as in the case of the positive coefficient, the pure de Sitter space is still globally preferred. This result is consistent with the argument that the pure de Sitter space corresponds to an UV fixed point of dual field theory.

Rong-Gen Cai and Qi Guo

2004-05-26T23:59:59.000Z

107

Acoustic white holes in flowing atomic Bose-Einstein condensates

We study acoustic white holes in a steadily flowing atomic Bose-Einstein condensate. A white hole configuration is obtained when the flow velocity goes from a super-sonic value in the upstream region to a sub-sonic one in the downstream region. The scattering of phonon wavepackets on a white hole horizon is numerically studied in terms of the Gross-Pitaevskii equation of mean-field theory: dynamical stability of the acoustic white hole is found, as well as a signature of a nonlinear back-action of the incident phonon wavepacket onto the horizon. The correlation pattern of density fluctuations is numerically studied by means of the truncated-Wigner method which includes quantum fluctuations. Signatures of the white hole radiation of correlated phonon pairs by the horizon are characterized; analogies and differences with Hawking radiation from acoustic black holes are discussed. In particular, a short wavelength feature is identified in the density correlation function, whose amplitude steadily grows in time since the formation of the horizon. The numerical observations are quantitatively interpreted by means of an analytical Bogoliubov theory of quantum fluctuations for a white hole configuration within the step-like horizon approximation.

Carlos Mayoral; Alessio Recati; Alessandro Fabbri; Renaud Parentani; Roberto Balbinot; Iacopo Carusotto

2010-09-30T23:59:59.000Z

108

Thermodynamic Geometry of Reissener-Nordström-de Sitter black hole and its extremal case

We study the thermodynamics and the different thermodynamic geometric methods of Reissener-Nordstr\\"{o}m-de Sitter black hole and its extremal case, which is similar to the de Sitter black hole coupled to a scalar field, rather called an MTZ black hole. While studying the thermodynamics of the systems, we could find some abnormalities. In both cases, the thermodynamic geometric methods could give the correct explanation for the all abnormal thermodynamic behaviors in the system.

R. Tharanath; Jishnu Suresh; Nijo Varghese; V. C. Kuriakose

2014-04-27T23:59:59.000Z

109

Extremal Black Holes and First Law of Thermodynamics

We study the low temperature expansion of the first law of thermodynamics for near-extremal black holes. We show that for extremal black holes with non-vanishing entropy, the leading order contribution yields an expression for their extremal entropy in agreement with the entropy function result and the Cardy formula for the entropy of a two dimensional chiral conformal field theory (CFT). When their entropy vanishes due to the vanishing of a one-cycle on the horizon, such leading contribution is always compatible with the first law satisfied by a BTZ black hole. These results are universal and consistent both with the presence of local AdS2 and AdS3 near horizon throats for extremal black holes and with the suggested quantum microscopic descriptions (AdS2/CFT1, Kerr/CFT and EVH/CFT).

Maria Johnstone; M. M. Sheikh-Jabbari; Joan Simon; Hossein Yavartanoo

2013-05-14T23:59:59.000Z

110

Laser stabilization using spectral hole burning

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.

L. Rippe; B. Julsgaard; A. Walther; S. Kröll

2006-11-05T23:59:59.000Z

111

Geometric description of BTZ black holes thermodynamics

We study the properties of the space of thermodynamic equilibrium states of the Ba\\~nados-Teitelboim-Zanelli (BTZ) black hole in (2+1)-gravity. We use the formalism of geometrothermodynamics to introduce in the space of equilibrium states a $2-$dimensional thermodynamic metric whose curvature is non-vanishing, indicating the presence of thermodynamic interaction, and free of singularities, indicating the absence of phase transitions. Similar results are obtained for generalizations of the BTZ black hole which include a Chern-Simons term and a dilatonic field. Small logarithmic corrections of the entropy turn out to be represented by small corrections of the thermodynamic curvature, reinforcing the idea that thermodynamic curvature is a measure of thermodynamic interaction.

Hernando Quevedo; Alberto Sanchez

2008-11-15T23:59:59.000Z

112

Conformal Symmetry of a Black Hole as a Scaling Limit: A Black Hole in an Asymptotically Conical Box

We show that the previously obtained subtracted geometry of four-dimensional asymptotically flat multi-charged rotating black holes, whose massless wave equation exhibit $SL(2,\\R) \\times SL(2,\\R) \\times SO(3)$ symmetry may be obtained by a suitable scaling limit of certain asymptotically flat multi-charged rotating black holes, which is reminiscent of near-extreme black holes in the dilute gas approximation. The co-homogeneity-two geometry is supported by a dilation field and two (electric) gauge-field strengths. We also point out that these subtracted geometries can be obtained as a particular Harrison transformation of the original black holes. Furthermore the subtracted metrics are asymptotically conical (AC), like global monopoles, thus describing "a black hole in an AC box". Finally we account for the the emergence of the $SL(2,\\R) \\times SL(2,\\R) \\times SO(3)$ symmetry as a consequence of the subtracted metrics being Kaluza-Klein type quotients of $ AdS_3\\times 4 S^3$. We demonstrate that similar properties hold for five-dimensional black holes.

M. Cvetic; G. W. Gibbons

2012-01-03T23:59:59.000Z

113

Core Hole Drilling And Testing At The Lake City, California Geothermal

Hole Drilling And Testing At The Lake City, California Geothermal Hole Drilling And Testing At The Lake City, California Geothermal Field Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Core Hole Drilling And Testing At The Lake City, California Geothermal Field Details Activities (4) Areas (1) Regions (0) Abstract: Unavailable Author(s): Dick Benoit, Joe Moore, Colin Goranson, David Blackwell Published: GRC, 2005 Document Number: Unavailable DOI: Unavailable Core Analysis At Lake City Hot Springs Area (Benoit Et Al., 2005) Core Holes At Lake City Hot Springs Area (Benoit Et Al., 2005) Flow Test At Lake City Hot Springs Area (Benoit Et Al., 2005) Static Temperature Survey At Lake City Hot Springs Area (Benoit Et Al., 2005) Lake City Hot Springs Geothermal Area Retrieved from "http://en.openei.org/w/index.php?title=Core_Hole_Drilling_And_Testing_At_The_Lake_City,_California_Geothermal_Field&oldid=389996

114

Electromagnetic field and cosmic censorship

We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.

Koray Düzta?

2014-04-09T23:59:59.000Z

115

Unified First Law and Thermodynamics of Dynamical Black Hole in n-dimensional Vaidya Spacetime

As a simple but important example of dynamical black hole, we analysis the dynamical black hole in $n$-dimensional Vaidya spacetime in detail. We investigated the thermodynamics of field equation in $n$-dimensional Vaidya spacetime. The unified first law was derived in terms of the methods proposed by Sean A Hayward. The first law of dynamical black hole was obtained by projecting the unified first law along the trapping horizon. At last, the second law of dynamical black hole is also discussed.

Ji-Rong Ren; Ran Li

2007-05-30T23:59:59.000Z

116

Black Holes, Entropies, and Semiclassical Spacetime in Quantum Gravity

We present a coherent picture of the quantum mechanics of black holes. The picture does not require the introduction of any drastically new physical effect beyond what is already known; it arises mostly from synthesizing and (re)interpreting existing results in appropriate manners. We identify the Bekenstein-Hawking entropy as the entropy associated with coarse-graining performed to obtain semiclassical field theory from a fundamental microscopic theory of quantum gravity. This clarifies the issues around the unitary evolution, the existence of the interior spacetime, and the thermodynamic nature in black hole physics--any result in semiclassical field theory is a statement about the maximally mixed ensemble of microscopic quantum states consistent with the specified background, within the precision allowed by quantum mechanics. We present a detailed analysis of information transfer in Hawking emission and black hole mining processes, clarifying what aspects of the underlying dynamics are (not) visible in sem...

Nomura, Yasunori

2014-01-01T23:59:59.000Z

117

This dissertation covers two di erent but related topics: the construction of new black hole solutions and the study of the microscopic origin of black hole entropy. In the solution part, two di erent sets of new solutions are found. The rst...

Mei, Jianwei

2010-10-12T23:59:59.000Z

118

Black Hole Energy Extraction Problems

Science Journals Connector (OSTI)

... non-rotating black hole the particle can be lowered to no closer than 1.14 Schwarzschild radii, and the energy extracted can be no more than 63.2 per cent ... gram of matter-and the rope could be lowered no closer than 5 x 1011 Schwarzschild radii. This seems to rule out black holes as practical sources of energy. ...

1972-11-24T23:59:59.000Z

119

Entropy of Lovelock Black Holes

A general formula for the entropy of stationary black holes in Lovelock gravity theories is obtained by integrating the first law of black hole mechanics, which is derived by Hamiltonian methods. The entropy is not simply one quarter of the surface area of the horizon, but also includes a sum of intrinsic curvature invariants integrated over a cross section of the horizon.

Ted Jacobson; Robert C. Myers

1993-05-06T23:59:59.000Z

120

We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.

Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

2005-02-07T23:59:59.000Z

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they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

121

Corrected form of the first law of thermodynamics for regular black holes

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.

Meng-Sen Ma; Ren Zhao

2014-11-04T23:59:59.000Z

122

Corrected form of the first law of thermodynamics for regular black holes

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.

Ma, Meng-Sen

2014-01-01T23:59:59.000Z

123

Curing black hole singularities with local scale invariance

We show that Weyl-invariant dilaton gravity provides a description of black holes without classical spacetime singularities. Singularities appear due to ill-behavior of gauge fixing conditions, one example being the gauge in which theory is classically equivalent to standard General Relativity. The main conclusions of our analysis are: (1) singularities signal a phase transition from broken to unbroken phase of Weyl symmetry, (2) instead of a singularity there is a "baby-universe" inside a black hole, (3) there is a critical mass after which reducing mass makes black hole larger as viewed by outside observers, (4) if a black hole could be connected with white hole through the "singularity", this would require breakdown of (classical) geometric description. The singularity of Schwarzschild BH solution is non-generic and so it it dangerous to rely on it in deriving general results. Our results may have important consequences for resolving issues related to information-loss puzzle. The theory we use is basically a completion of General Relativity, containing neither additional physical excitations nor higher-derivative terms, but requires physical scalar field such as Higgs field of Standard Model. Though quantum effects are still crucial and may change the proposed classical picture, a position of building quantum theory around regular classical solutions (without singularities) normally provides a much better starting point.

Predrag Dominis Prester

2014-02-27T23:59:59.000Z

124

Reissner-Nordstrom black hole in dark energy background

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.

Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh

2014-11-29T23:59:59.000Z

125

The Inside Story: Quasilocal Tachyons and Black Holes

We analyze the fate of excitations in regions of closed string tachyon condensate, a question crucial for understanding unitarity in a class of black holes in string theory. First we introduce a simple new example of quasilocal tachyon condensation in a globally stable AdS/CFT background, and review tachyons' appearance in black hole physics. Then we calculate forces on particles and fields in a tachyon phase using a field theoretic model with spatially localized exponentially growing time dependent masses. This model reveals two features, both supporting unitary evolution in the bulk of spacetime. First, the growing energy of fields sourced by sets of (real and virtual) particles in the tachyon phase yields outward forces on them, leaving behind only combinations which do not source any fields. Secondly, requiring the consistency of perturbative string theory imposes cancellation of a BRST anomaly, which also yields a restricted set of states. Each of these effects supports the notion of a black hole final state arising from string-theoretic dynamics replacing the black hole singularity.

Horowitz, Gary T.; /UC, Santa Barbara; Silverstein, Eva; /SLAC /Stanford U., Phys. Dept.

2006-01-13T23:59:59.000Z

126

A scale-free analysis of magnetic holes in the solar wind

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 ...

Stevens, M. L. (Michael Louis)

2006-01-01T23:59:59.000Z

127

The structure of black hole magnetospheres — I. Schwarzschild black holes

Science Journals Connector (OSTI)

......2000 RAS, MNRAS 315, 89 97 force-free black hole magnetosphere...However, there is nothing fundamental about the paraboloidal shape...in stationary axisymmetric force-free magnetospheres. Therefore...Stegun I. A., 1972, Handbook of Mathematical Functions......

Pranab Ghosh

2000-06-11T23:59:59.000Z

128

Black Holes in Active Galaxies

Recent years have seen tremendous progress in the quest to detect supermassive black holes in the centers of nearby galaxies, and gas-dynamical measurements of the central masses of active galaxies have been valuable contributions to the local black hole census. This review summarizes measurement techniques and results from observations of spatially resolved gas disks in active galaxies, and reverberation mapping of the broad-line regions of Seyfert galaxies and quasars. Future prospects for the study of black hole masses in active galaxies, both locally and at high redshift, are discussed.

A. J. Barth

2003-10-15T23:59:59.000Z

129

Thermodynamics of Lifshitz black holes

Science Journals Connector (OSTI)

We apply the recently extended conserved Killing charge definition of Abbott-Deser-Tekin formalism to compute, for the first time, the energies of analytic Lifshitz black holes in higher dimensions. We then calculate the temperature and the entropy of this large family of solutions, and study and discuss the first law of black hole thermodynamics. Along the way we also identify the possible critical points of the relevant quadratic curvature gravity theories. Separately, we also apply the generalized Killing charge definition to compute the energy and the angular momentum of the warped AdS3 black hole solution of the three-dimensional new massive gravity theory.

Deniz Olgu Devecio?lu and Özgür Sar?o?lu

2011-06-23T23:59:59.000Z

130

Semiclassical decay of near-extremal black holes

Science Journals Connector (OSTI)

The decay of a near-extremal black hole down to the extremal state is studied in the background field approximation to determine the fate of injected matter and Hawking pairs. By examining the behavior of light rays and solutions to the wave equation it is concluded that the singularity at the origin is irrelevant. Furthermore, there is most likely an instability of the event horizon arising from the accumulation of injected matter and Hawking partners there. The possible role of this instability in reconciling the D-brane and black hole pictures of the decay process is discussed.

Ted Jacobson

1998-04-15T23:59:59.000Z

131

Dirac monopoles on Kerr black holes: comparing gauges

We update our previous work on the description of twisted configurations for complex massless scalar field on the Kerr black holes as the sections of complex line bundles over the Kerr black hole topology. From physical point of view the appearance of twisted configurations is linked with the natural presence of Dirac monopoles that arise as connections in the above line bundles. We consider their description in the gauge inequivalent to the one studied previously and discuss a row of new features appearing in this gauge.

Yu. P. Goncharov

1998-11-17T23:59:59.000Z

132

Electromagnetic partner of the gravitational signal during accretion onto black holes

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.

Juan Carlos Degollado; Victor Gualajara; Claudia Moreno; Darío Núñez

2014-10-21T23:59:59.000Z

133

Slim Holes | Open Energy Information

Slim Holes Slim Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Slim Holes Details Activities (30) Areas (24) Regions (1) NEPA(6) Exploration Technique Information Exploration Group: Drilling Techniques Exploration Sub Group: Exploration Drilling Parent Exploration Technique: Exploration Drilling Information Provided by Technique Lithology: If core is collected Stratigraphic/Structural: If core is collected Hydrological: Fluid flow and water chemistry Thermal: Thermal gradient or bottom hole temperature Cost Information Low-End Estimate (USD): 100.0010,000 centUSD 0.1 kUSD 1.0e-4 MUSD 1.0e-7 TUSD / foot Median Estimate (USD): 169.8916,989 centUSD 0.17 kUSD 1.6989e-4 MUSD 1.6989e-7 TUSD / foot High-End Estimate (USD): 200.0020,000 centUSD

134

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Tree Hole Tree Hole Nature Bulletin No. 581 November 21, 1959 Forest Preserve District of Cook County Daniel Ryan, President Roberts Mann, Conservation Editor David H Thompson, Senior Naturalist LIFE IN A TREE HOLE A forest is much more than just trees. It includes all of the underbrush, wildflowers and other vegetation that grow beneath these trees; as well as all of its animal life, both large and small. Sunshine, rain, wind, soil, and the leaf litter on the ground are part of it, too. A forest is a community -- a fabric in which the lives of its inhabitants are woven together and into their surroundings by a complex web of interrelations. Tree holes -- together with the birds, mammals and small life which they shelter -- furnish an important binding force in this forest community.

135

Thermodynamics of regular black hole

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.

Yun Soo Myung; Yong-Wan Kim; Young-Jai Park

2007-08-23T23:59:59.000Z

136

Primordial black holes from temporally enhanced curvature perturbation

Scalar field with generalized kinetic interactions metamorphoses depending on its field value, ranging from cosmological constant to stiff matter. We show that such a scalar field can give rise to temporal enhancement of the curvature perturbation in the primordial Universe, leading to efficient production of primordial black holes while the enhancement persists. If the inflation energy scale is high, those mini-black holes evaporate by the Hawking radiation much before Big Bang nucleosynthesis and the effective reheating of the Universe is achieved by the black hole evaporation. Dominance of PBHs and the reheating by their evaporation modify the expansion history of the primordial Universe. This results in a characteristic feature of the spectrum of primordial tensor modes in the DECIGO frequency band, opening an interesting possibility of testing PBH reheating scenario by measuring the primordial tensor modes. If the inflation energy scale is low, the PBH mass can be much larger than the solar mass. In this case, PBH is an interesting candidate for seeds for supermassive black holes residing in present galaxies.

Teruaki Suyama; Yi-Peng Wu; Jun'ichi Yokoyama

2014-06-02T23:59:59.000Z

137

Of the Black Hole Thermodynamics

About thirty years ago, Bekenstein and Hawking introduced three basic concepts relating to black hole, namely, the "area entropy", "gravitation temperature" and "thermal radiation". The author analyzes these concepts systematically and concludes that they are mostly inadequate or wrong. He points out that a black hole's taking in thermal radiation from the space is an energy-gathering process. It is special, even extraordinary. It reduces entropy, violating Clausius' second law.

Xinyong Fu

2005-01-11T23:59:59.000Z

138

Seven Mile Hole Geothermal Area | Open Energy Information

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon Â» Seven Mile Hole Geothermal Area (Redirected from Seven Mile Hole Area) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermal Resource Area: Seven Mile Hole Geothermal Area Contents 1 Area Overview 2 History and Infrastructure 3 Regulatory and Environmental Issues 4 Exploration History 5 Well Field Description 6 Geology of the Area 7 Geofluid Geochemistry 8 NEPA-Related Analyses (0) 9 Exploration Activities (4) 10 References Area Overview Geothermal Area Profile Location: Wyoming Exploration Region: Yellowstone Caldera Geothermal Region GEA Development Phase:

139

Massive Black Hole Science with eLISA

The evolving Laser Interferometer Space Antenna (eLISA) will revolutionize our understanding of the formation and evolution of massive black holes along cosmic history by probing massive black hole binaries in the $10^3-10^7$ solar mass range out to redshift $z\\gtrsim 10$. High signal-to-noise ratio detections of $\\sim 10-100$ binary coalescences per year will allow accurate measurements of the parameters of individual binaries (such as their masses, spins and luminosity distance), and a deep understanding of the underlying cosmic massive black hole parent population. This wealth of unprecedented information can lead to breakthroughs in many areas of physics, including astrophysics, cosmology and fundamental physics. We review the current status of the field, recent progress and future challenges.

Enrico Barausse; Jillian Bellovary; Emanuele Berti; Kelly Holley-Bockelmann; Brian Farris; Bangalore Sathyaprakash; Alberto Sesana

2015-01-09T23:59:59.000Z

140

Black/White hole radiation from dispersive theories

We study the fluxes emitted by black holes when using dispersive field theories. We work with stationary one dimensional backgrounds which are asymptotically flat on both sides of the horizon. The asymptotic fluxes are governed by a 3x3 Bogoliubov transformation. The fluxes emitted by the corresponding white holes are regular and governed by the inverse transformation. We numerically compute the spectral properties of these fluxes for both sub- and superluminal quartic dispersion. The leading deviations with respect to the dispersionless flux are computed and shown to be governed by a critical frequency above which there is no radiation. Unlike the UV scale governing dispersion, its value critically depends on the asymptotic properties of the background. We also study the flux outside the robust regime. In particular we show that its low frequency part remains almost thermal but with a temperature which significantly differs from the standard one. Application to four dimensional black holes and Bose-Einstein condensates are in preparation.

Jean Macher; Renaud Parentani

2009-06-02T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

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141

The Schwarzschild black hole as a gravitational mirror

Science Journals Connector (OSTI)

The gravitational field outside of a nonrotating black hole is described using the Schwarzschild metric. The geodesic equations of the Schwarzschild metric are derived and those describing null and circular timelike orbits are discussed. Some numerical solutions of the null geodesic equations are shown. These depict photon trajectories which circle the black hole one or two times and then terminate at their emission points. Thus a sequence of ring?shaped mirror images is produced. An equation which gives the angle between the photon’s trajectory and the radial direction at the emitter is derived and applied to the numerical solutions. These results serve to illustrate how an observer ‘‘passes through’’ his or her mirror image at r=3 MG/c 2 as he or she moves toward a Schwarzschild black hole.

W. M. Stuckey

1993-01-01T23:59:59.000Z

142

Thermal stress on bottom hole rock of gas drilling

Science Journals Connector (OSTI)

Gas drilling has higher penetration than mud drilling. The greatest reason for this phenomenon with gas is that the gas is greatly cooled by expansion as it passes through the bit and thereby cools the bottom of the hole. The thermal stress at bottom-hole occurs during this process. The concept of thermal crushing of rocks is analysed in this study. The theoretical methods are developed to analyse thermal stresses and fragmentation induced by cooling of rock. Then, the numerical computation is conducted for the thermal stress equations with the numerical result simulated for the temperature field at the bottom hole to explain the reason of high drilling rates in gas drilling. Furthermore, an experiment was conducted to verify the theory. Therefore, the theories and simulated results in this paper have a guiding signification for best understand the technique and possibly to extend its economic advantage still further. [Received: September 23, 2011; Accepted: November 20, 2011

Shunji Yang; Gonghui Liu; Jun Li

2012-01-01T23:59:59.000Z

143

Seven Mile Hole Geothermal Area | Open Energy Information

Seven Mile Hole Geothermal Area Seven Mile Hole Geothermal Area Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermal Resource Area: Seven Mile Hole Geothermal Area Contents 1 Area Overview 2 History and Infrastructure 3 Regulatory and Environmental Issues 4 Exploration History 5 Well Field Description 6 Geology of the Area 7 Geofluid Geochemistry 8 NEPA-Related Analyses (0) 9 Exploration Activities (4) 10 References Area Overview Geothermal Area Profile Location: Wyoming Exploration Region: Yellowstone Caldera Geothermal Region GEA Development Phase: 2008 USGS Resource Estimate Mean Reservoir Temp: Estimated Reservoir Volume: Mean Capacity: Click "Edit With Form" above to add content History and Infrastructure Operating Power Plants: 0 No geothermal plants listed. Add a new Operating Power Plant

144

Stellar black holes and the origin of cosmic acceleration

Science Journals Connector (OSTI)

The discovery of cosmic acceleration has presented a unique challenge for cosmologists. As observational cosmology forges ahead, theorists have struggled to make sense of a standard model that requires extreme fine-tuning. This challenge is known as the cosmological constant problem. The theory of gravitational aether is an alternative to general relativity that does not suffer from this fine-tuning problem, as it decouples the quantum field theory vacuum from geometry, while remaining consistent with other tests of gravity. In this paper, we study static black hole solutions in this theory and show that it manifests a UV-IR coupling: Aether couples the space-time metric close to the black hole horizon, to metric at infinity. We then show that using the trans-Planckian ansatz (as a quantum gravity effect) close to the black hole horizon, leads to an accelerating cosmological solution, far from the horizon. Interestingly, this acceleration matches current observations for stellar-mass black holes. Based on our current understanding of the black hole accretion history in the Universe, we then make a prediction for how the effective dark energy density should evolve with redshift, which can be tested with future dark energy probes.

Chanda Prescod-Weinstein; Niayesh Afshordi; Michael L. Balogh

2009-08-18T23:59:59.000Z

145

Black Hole Motion as Catalyst of Orbital Resonances

The motion of a black hole about the centre of gravity of its host galaxy induces a strong response from the surrounding stellar population. We treat the case of a harmonic potential analytically and show that half of the stars on circular orbits in that potential shift to an orbit of lower energy, while the other half receive a positive boost and recede to a larger radius. The black hole itself remains on an orbit of fixed amplitude and merely acts as a catalyst for the evolution of the stellar energy distribution function f(E). We show that this effect is operative out to a radius of approx 3 to 4 times the hole's influence radius, R_bh. We use numerical integration to explore more fully the response of a stellar distribution to black hole motion. We consider orbits in a logarithmic potential and compare the response of stars on circular orbits, to the situation of a `warm' and `hot' (isotropic) stellar velocity field. While features seen in density maps are now wiped out, the kinematic signature of black hole motion still imprints the stellar line-of-sight mean velocity to a magnitude ~18% the local root mean-square velocity dispersion sigma.

C. M. Boily; T. Padmanabhan; A. Paiement

2007-05-18T23:59:59.000Z

146

Geothermal slim holes for small off-grid power projects

Science Journals Connector (OSTI)

Economically viable, small (100 kWe to 1000 kWe), geothermal power generation units using slim holes are available for the production of electrical power in remote areas and for rural electrification in developing countries. Based on borehole data from geothermal fields in the United States and Japan, slim holes have been proven as adequate fuel sources for small-scale geothermal power plants (SSGPPs) and can deliver enough geothermal fluid to the wellhead in a baseload mode to be of practical interest for off-grid electrification projects. The electrical generating capacity of geothermal fluids which can be produced from typical slim holes (150-mm diameter or less), both by conventional, self-discharge, flash-steam methods for hotter geothermal reservoirs, and by binary-cycle technology with downhole pumps for low- to moderate-temperature reservoirs are estimated using a simplified theoretical approach. Depending mainly on reservoir temperature, the numerical simulations indicate that electrical capacities from a few hundred kilowatts to over one megawatt per slim hole are possible. In addition to the advantage of price per kilowatt-hour in off-grid applications, \\{SSGPPs\\} fueled by slim holes are far more environmentally benign than fossil-burning power plants, which is crucial in view of current worldwide climate-change concerns and burgeoning electricity demand in the less-developed and developing countries.

Jim Combs; Sabodh K Garg; John W Pritchett

1997-01-01T23:59:59.000Z

147

Black hole quantum tunnelling and black hole entropy correction

Parikh-Wilczek tunnelling framework, which treats Hawking radiation as a tunnelling process, is investigated again. As the first order correction, the log-corrected entropy-area relation naturally emerges in the tunnelling picture if we consider the emission of a spherical shell. The second order correction of the emission rate for the Schwarzschild black hole is calculated too. In this level, the result is still in agreement with the unitary theory, however, the entropy of the black hole will contain three parts: the usual Bekenstein-Hawking entropy, the logarithmic term and the inverse area term. In our results the coefficient of the logarithmic term is -1. Apart from a coefficient, Our correction to the black hole entropy is consistent with that of loop quantum gravity.

Jingyi Zhang

2008-06-15T23:59:59.000Z

148

Core Holes At Lake City Hot Springs Area (Benoit Et Al., 2005) | Open

Holes At Lake City Hot Springs Area (Benoit Et Holes At Lake City Hot Springs Area (Benoit Et Al., 2005) Exploration Activity Details Location Lake City Hot Springs Area Exploration Technique Core Holes Activity Date Usefulness useful DOE-funding Unknown Notes Three core holes drilled between 2002 and 2005. Depths: 1,728; 3,435; 4,727 ft. Two deeper wells encountered temps of 327 and 329 oF and permable fractures in sedimentary and volcanic rocks; enabled injection and flow testing up to 70 gpm. Quartz fluid inclusions give temps of 264 and 316 oF. Core drillling allowed an understanding of geology and geothermal system that could never have been obtained from cuttings in this particular geologic setting. References Dick Benoit, Joe Moore, Colin Goranson, David Blackwell (2005) Core Hole Drilling And Testing At The Lake City, California Geothermal Field

149

Hole depletion of ladders in Sr14Cu24O41 induced by correlation effects

Science Journals Connector (OSTI)

The hole distribution in Sr14Cu24O41 is studied by low-temperature polarization-dependent O K near-edge x-ray absorption fine-structure measurements and state-of-the-art electronic structure calculations that include core-hole and correlation effects in a mean-field approach. Contrary to all previous analysis, based on semiempirical models, we show that correlations and antiferromagnetic ordering favor the strong chain-hole attraction. For the remaining small number of holes accommodated on ladders, leg sites are preferred to rung sites. The small hole affinity of rung sites explains naturally the one-dimensional to two-dimensional crossover in the phase diagram of (La,Y,Sr,Ca)14Cu24O41.

V. Ilakovac; C. Gougoussis; M. Calandra; N. B. Brookes; V. Bisogni; S. G. Chiuzbaian; J. Akimitsu; O. Milat; S. Tomi?; C. F. Hague

2012-02-07T23:59:59.000Z

150

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hole in the ozone layer? Hole in the ozone layer? Name: Kelley Location: N/A Country: N/A Date: N/A Question: Is there really a hole in the ozone layer? Replies: That depends on what one means by a "hole". There is a thinning of the layer that is particularly severe during certain seasons at the poles. But the ozone layer is thinning most everywhere. The thinning around the south pole of earth is particularly stunning, and has been referred to as a hole even though some ozone still exists there, it is much less concentrated. As you may know, this ozone destruction is probably due to human release of pollutants such as clorofluorocarbons (CFCs) an due to natural sources such as chemicals from volcanic eruptions. CFCs are used is cooling systems such as refrigerators and air conditioning. There is an international agreement to phase out the use of these destructive chemicals but they won't be banned entirely for years for fears of losing money. Meanwhile the ozone layer thins and we are exposed to increasingly higher doses of cancer causing radiation

151

LOW-LATITUDE CORONAL HOLES, DECAYING ACTIVE REGIONS, AND GLOBAL CORONAL MAGNETIC STRUCTURE

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.

Petrie, G. J. D. [National Solar Observatory, Tucson, AZ 85719 (United States); Haislmaier, K. J. [George Mason University, Fairfax, VA 22030 (United States)

2013-10-01T23:59:59.000Z

152

Bulk emission of scalars by a rotating black hole

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.

M. Casals; S. R. Dolan; P. Kanti; E. Winstanley

2008-07-17T23:59:59.000Z

153

Probing the puncture for black hole simulations

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.

Brown, J. David [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2009-10-15T23:59:59.000Z

154

Energy on black hole spacetimes

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.

Alejandro Corichi

2012-07-18T23:59:59.000Z

155

Coherence effects in hole superconductivity

Science Journals Connector (OSTI)

We discuss the behavior of various observables that depend on matrix elements of operators in the superconducting state within the model of hole superconductivity. In this model, the gap exhibits a linear dependence on the band energy, and the bandwidth depends on the carrier concentration and can become very small for low hole density. We study, in particular, the behavior of ultrasonic attenuation, NMR relaxation rate, and electromagnetic absorption, and present results for parameters expected to be in the range that describes the high-Tc oxides. It is found that the energy dependence of the gap does not give rise to qualitatively different behavior, but significant differences from weak-coupling BCS behavior occur at low hole concentration due to the extreme narrowness of the band.

F. Marsiglio and J. E. Hirsch

1991-12-01T23:59:59.000Z

156

Information loss in black holes

Science Journals Connector (OSTI)

The question of whether information is lost in black holes is investigated using Euclidean path integrals. The formation and evaporation of black holes is regarded as a scattering problem with all measurements being made at infinity. This seems to be well formulated only in asymptotically AdS spacetimes. The path integral over metrics with trivial topology is unitary and information preserving. On the other hand, the path integral over metrics with nontrivial topologies leads to correlation functions that decay to zero. Thus at late times only the unitary information preserving path integrals over trivial topologies will contribute. Elementary quantum gravity interactions do not lose information or quantum coherence.

S. W. Hawking

2005-10-18T23:59:59.000Z

157

Black hole binary inspiral and trajectory dominance

Gravitational waves emitted during the inspiral, plunge and merger of a black hole binary carry linear momentum. This results in an astrophysically important recoil to the final merged black hole, a “kick” that can eject ...

Price, Richard H.

158

Influence of the back reaction of the Hawking radiation upon black hole quasinormal modes

Science Journals Connector (OSTI)

We consider the BTZ black hole surrounded by the conformal scalar field. Within general relativity, the resonant quasinormal (QN) modes dominate in the response of a black hole to external perturbations. At the same time, the metric of an evaporating black hole is affected by the Hawking radiation. We estimate the shift in the quasinormal spectrum of the BTZ black hole stipulated by the back reaction of the Hawking radiation. For the case of the (2+1)-dimensional black hole the corrected (by ??) metric is an exact solution [C. Martines and J. Zanelli, Phys. Rev. D 55, 3642 (1997)]. In addition, in this case quantum corrections come only from matter fields and not from graviton loops, that is, one can solve the problem of influence of the back reaction upon the QN ringing self-consistently. The dominant contribution to the corrections to the QNMs is simply a shift of ?2 proportional to -(?/M)3/2(4L2+M)?. It is negligible for large black holes but essential for small ones, giving rise to considerable increasing of the quality factor. Thus, the small evaporating black hole is expected to be a much better oscillator than a large one.

R. A. Konoplya

2004-08-18T23:59:59.000Z

159

Hawking Emission and Black Hole Thermodynamics

A brief review of Hawking radiation and black hole thermodynamics is given, based largely upon hep-th/0409024.

Don N. Page

2006-12-18T23:59:59.000Z

160

Ion Feedback Suppression Using Inclined MCP Holes in a _Single-MCP+Micromegas+Pads_ Detector

We show that the ion backflow to photocathode can be completely suppressed if one uses inclined MCP holes in a presence of magnetic field. The inclined hole angles are chosen to be aligned with the Lorentz electron angle allowing the electron transmission and amplification, while positive ions, traveling along a different angle, are caught on the MCP hole walls. The detector under investigation is a new gaseous detector structure based on a tandem of two parts, a single MCP (Microchannel) plate, a Micromegas with pad readout. We are aiming to develop a gaseous photon detector with the Bialkali photocathode, however, one could use some ideas in the paper for other types of detectors.

Va'vra, J.; /SLAC; Sumiyoshi, T.; /Tokyo Metropolitan U.

2005-09-30T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

161

Using radio emission to detect isolated and quiescent accreting black holes

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.

Thomas J. Maccarone

2005-03-05T23:59:59.000Z

162

The Matter Plus Black Hole Problem in Axisymmetry

We present preliminary results in our long-term project of studying the evolution of matter in a dynamical spacetime. To achieve this, we have developed a new code to evolve axisymmetric initial data sets corresponding to a black hole surrounded by matter fields. The code is based on the coupling of two previously existing codes. The matter fields are evolved with a 2D shock-capturing method which uses the characteristic information of the GR hydro equations to build up a linearized Riemann solver. The spacetime is evolved with a 2D ADM code designed to evolve a wormhole in full general relativity. An example of the kind of problems we are currently investigating is the on axis collision of a star with a black hole.

S. R. Brandt; J. A. Font

1997-11-06T23:59:59.000Z

163

High precision, rapid laser hole drilling

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.

Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

2013-04-02T23:59:59.000Z

164

Time (hole?) machines John Byron Manchak

Time (hole?) machines John Byron Manchak Department of Philosophy, University of Washington, Box machines Hole machines Time travel General relativity a b s t r a c t Within the context of general relativity, we consider a type of "time machine" and introduce the related "hole machine". We review what

Manchak, John

165

Absorption cross section in Lifshitz black hole

We derive the absorption cross section of a minimally coupled scalar in the Lifshitz black hole obtained from the new massive gravity. The absorption cross section reduces to the horizon area in the low energy and massless limit of s-wave mode propagation, indicating that the Lifshitz black hole also satisfies the universality of low energy absorption cross section for black holes.

Taeyoon Moon; Yun Soo Myung

2012-05-10T23:59:59.000Z

166

The problem of physical process version of the first law of black hole thermodynamics for charged rotating black hole in n-dimensional gravity is elaborated. The formulas for the first order variations of mass, angular momentum and canonical energy in Einstein (n-2)-gauge form field theory are derived. These variations are expressed by means of the perturbed matter energy momentum tensor and charge matter current density.

Rogatko, Marek [Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, pl.Marii Curie-Sklodowskiej 1 (Poland)

2005-05-15T23:59:59.000Z

167

Absorption cross section of RN and SdS extremal black hole

The nature of scalar wave functions near the horizon of Reissner Nordstrom (RN) extremal and Schwarzschild-de Sitter (SdS) extremal black holes are found using WKB approximation and the effect of reflection of waves from the horizon. The absorption cross section $\\sigma_{abs}$ when RN extremal and SdS extremal black holes placed in a Klein-Gordon field is calculated.

Sini R; Nijo Varghese; V C Kuriakose

2008-02-29T23:59:59.000Z

168

TESTING COWLING'S ANTIDYNAMO THEOREM NEAR A ROTATING BLACK HOLE AXEL BRANDENBURG1

hole. In the cases investigated it is found that a magnetic field cannot be sustained against ohmic-excited axisymmetric solutions. In practice, therefore, Cowling's antidynamo theorem may still hold in Kerr geometry of processes depicted above, only changes in the azimuthal electric and magnetic fields by stretching

Brandenburg, Axel

169

Ultrafast Core-Hole Induced Dynamics in Water

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ultrafast Core-Hole Induced Ultrafast Core-Hole Induced Dynamics in Water Ultrafast Core-Hole Induced Dynamics in Water Print Wednesday, 22 February 2006 00:00 A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems 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 water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

170

Supermassive black holes from supermassive stars

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Supermassive black holes from supermassive stars Supermassive black holes from supermassive stars 1663 Los Alamos science and technology magazine Latest Issue:November 2013 All Issues Â» submit Supermassive black holes from supermassive stars Supermassive stars in the early universe gave supermassive black holes a head start March 25, 2013 simulations suggest that star formation conditions back then allowed the first stars to become supermassive themselves In this simulation, a black hole that was just formed by the collapse of a supermassive star is surrounded by a distribution of gas (color indicates density). Because the black hole (located at the center but too small to see) grows by consuming the available gas, simulations like this one help determine how quickly the black hole can grow. The progenitor of this black

171

Accelerating and rotating black holes

An exact solution of Einstein's equations which represents a pair of accelerating and rotating black holes (a generalised form of the spinning C-metric) is presented. The starting point is a form of the Plebanski-Demianski metric which, in addition to the usual parameters, explicitly includes parameters which describe the acceleration and angular velocity of the sources. This is transformed to a form which explicitly contains the known special cases for either rotating or accelerating black holes. Electromagnetic charges and a NUT parameter are included, the relation between the NUT parameter $l$ and the Plebanski-Demianski parameter $n$ is given, and the physical meaning of all parameters is clarified. The possibility of finding an accelerating NUT solution is also discussed.

J. B. Griffiths; J. Podolsky

2005-07-06T23:59:59.000Z

172

In these two lectures, we will address the topic of the creation of small black holes during particle collisions in a ground-based accelerator, such as LHC, in the context of a higher-dimensional theory. We will cover the main assumptions, criteria and estimates for their creation, and we will discuss their properties after their formation. The most important observable effect associated with their creation is likely to be the emission of Hawking radiation during their evaporation process. After presenting the mathematical formalism for its study, we will review the current results for the emission of particles both on the brane and in the bulk. We will finish with a discussion of the methodology that will be used to study these spectra, and the observable signatures that will help us identify the black-hole events.

Panagiota Kanti

2008-02-15T23:59:59.000Z

173

Down hole periodic seismic generator

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.

Hardee, Harry C. (Albuquerque, NM); Hills, Richard G. (Las Cruces, NM); Striker, Richard P. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

174

Primordial black hole minimum mass

In this paper we revisit thermodynamic constraints on primordial black hole (PBH) formation in the early universe. Under the assumption that PBH mass is equal to the cosmological horizon mass, one can use the 2nd Law of Thermodynamics to put a lower limit on the PBH mass. In models of PBH formation, however, PBHs are created at some fraction of the horizon mass. We show that this thermodynamic constraint still holds for subhorizon PBH formation.

Chisholm, James R. [Institute for Fundamental Theory, University of Florida, Gainesville, Florida 32611-8440 (United States)

2006-08-15T23:59:59.000Z

175

Black Hole Thermodynamics and Electromagnetism

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.

Burra G. Sidharth

2005-07-15T23:59:59.000Z

176

Temperature, Energy, and Heat Capacity of Asymptotically Anti-De Sitter Black Holes

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.

J. D. Brown; J. Creighton; R. B. Mann

1994-05-03T23:59:59.000Z

177

Quantum Geometry and Black Holes

We present an overall picture of the advances in the description of black hole physics from the perspective of loop quantum gravity. After an introduction that discusses the main conceptual issues we present some details about the classical and quantum geometry of isolated horizons and their quantum geometry and then use this scheme to give a natural definition of the entropy of black holes. The entropy computations can be neatly expressed in the form of combinatorial problems solvable with the help of methods based on number theory and the use of generating functions. The recovery of the Bekenstein-Hawking law and corrections to it is explained in some detail. After this, due attention is paid to the discussion of semiclassical issues. An important point in this respect is the proper interpretation of the horizon area as the energy that should appear in the statistical-mechanical treatment of the black hole model presented here. The chapter ends with a comparison between the microscopic and semiclassical app...

G., J Fernando Barbero

2015-01-01T23:59:59.000Z

178

Moduli, Scalar Charges, and the First Law of Black Hole Thermodynamics

Science Journals Connector (OSTI)

We show that under variation of moduli fields ? the first law of black hole thermodynamics becomes dM=?dA8?+?dJ+?dq+?dp-?d?, where ? are the scalar charges. Also the Arnowitt-Desner-Misner mass is extremized at fixed A, J, (p,q) when the moduli fields take the fixed value ?fix(p,q) which depend only on electric and magnetic charges. Thus the double-extreme black hole minimizes the mass for fixed conserved charges. We can now explain the fact that extreme black holes fix the moduli fields at the horizon ?=?fix(p,q): ?fix is such that the scalar charges vanish: ?(?fix,(p,q))=0.

Gary Gibbons; Renata Kallosh; Barak Kol

1996-12-16T23:59:59.000Z

179

Science Journals Connector (OSTI)

The momentum distribution and the quasi-hole strength in symmetric nuclear matter have been calculated for two densities in the framework of the Brueckner-Bethe-Goldstone theory. A separable version of the Argonne v14 has been used as realistic NN interaction in the self-consistent procedure to determine the g-matrix and the corresponding mean field. The results for quasi-hole strength have been compared with other calculations and also with the hole-state spectroscopic factor extracted from recent (e,e?p) knock-out reactions on 90Zr and 208Pb. On the basis of the hole-line expansion higher-order contributions to the momentum distribution have been included in the calculations resulting in a better fulfillment of the Migdal-Luttinger theorem.

M. Baldo; I. Bombaci; G. Giansiracusa; U. Lombardo

1991-01-01T23:59:59.000Z

180

Quasinormal modes for the SdS black hole : an analytical approximation scheme

Quasinormal modes for scalar field perturbations of a Schwarzschild-de Sitter (SdS) black hole are investigated. An analytical approximation is proposed for the problem. The quasinormal modes are evaluated for this approximate model in the limit when black hole mass is much smaller than the radius of curvature of the spacetime. The model mirrors some striking features observed in numerical studies of time behaviour of scalar perturbations of the SdS black hole. In particular, it shows the presence of two sets of modes relevant at two different time scales, proportional to the surface gravities of the black hole and cosmological horizons respectively. These quasinormal modes are not complete - another feature observed in numerical studies. Refinements of this model to yield more accurate quantitative agreement with numerical studies are discussed. Further investigations of this model are outlined, which would provide a valuable insight into time behaviour of perturbations in the SdS spacetime.

V. Suneeta

2003-03-31T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

181

On the temperature dependence of the absorption cross section for charged black holes

We analyze the the low frequency absorption cross section of minimally coupled massless scalar fields by different kinds of charged static black holes, namely the d-dimensional Reissner-Nordstrom solution, the D1-D5 system in d=5 and a four dimensional dyonic four-charged black hole. In each case we show that this cross section is inversely proportional to the black hole Hawking temperature. This inverse proportionality also arises in the same cross section for black holes with string $alpha' corrections, as we have shown in a previous work: string corrections induce such temperature dependence. In each case we also carefully analyze the extremal limit and show that the cross section is well defined in it.

Filipe Moura

2014-06-08T23:59:59.000Z

182

Singularities, geodesics and Green functions in the BTZ black hole

In the context of studying black hole singularities by the AdS/CFT correspondence, we study the BTZ black hole by a scalar field propagating on it and the corresponding two-point Green functions. We explore how positions inside the horizon are encoded in the boundary theory. The main idea is to relate two different semi-classical approximations of the Green function and see how this indicates the bulk-boundary correspondence. From a key observation of Festucia and Liu, which is a frequency-geodesic identification, we deduce a geodesic approximation from the saddle point approximation. As an application, we find saddles of the Green function and hence their corresponding geodesics. The conclusion is that some of these geodesics do go inside the horizon. This gives the possibility of resolving the singularity from the boundary theory.

Chen Yang

2006-11-04T23:59:59.000Z

183

Spinning Black Holes as Particle Accelerators

Science Journals Connector (OSTI)

It has recently been pointed out that particles falling freely from rest at infinity outside a Kerr black hole can in principle collide with an arbitrarily high center of mass energy in the limiting case of maximal black hole spin. Here we aim to elucidate the mechanism for this fascinating result, and to point out its practical limitations, which imply that ultraenergetic collisions cannot occur near black holes in nature.

Ted Jacobson and Thomas P. Sotiriou

2010-01-14T23:59:59.000Z

184

Black hole entropy: inside or out?

A trialogue. Ted, Don, and Carlo consider the nature of black hole entropy. Ted and Carlo support the idea that this entropy measures in some sense ``the number of black hole microstates that can communicate with the outside world.'' Don is critical of this approach, and discussion ensues, focusing on the question of whether the first law of black hole thermodynamics can be understood from a statistical mechanics point of view.

Ted Jacobson; Donald Marolf; Carlo Rovelli

2005-01-14T23:59:59.000Z

185

Interaction of fermions with black holes

Bekenstein and Meisels used statistical thermodynamic arguments to obtain the probability distribution of fermions emitted by a black hole when a fermion is incident. In contrast with Bekenstein and Meisels, we model the black hole as a perfect blackbody surrounded by a mirror. Our probability distribution for emitted fermions agrees with the probability distribution of Bekenstein and Meisels, but the interpretation of how fermions interact with the black hole is different from the interpreteation given by Bekenstein and Meisels.

Jones T.O. III

1986-04-15T23:59:59.000Z

186

Electromagnetic Beams Overpass the Black Hole Horizon

We show that the electromagnetic excitations of the Kerr black hole have very strong back reaction on metric. In particular, the electromagnetic excitations aligned with the Kerr congruence form the light-like beams which overcome horizon, forming the holes in it, which allows matter to escape interior. So, there is no information lost inside the black hole. This effect is based exclusively on the analyticity of the algebraically special solutions.

Alexander Burinskii

2008-06-16T23:59:59.000Z

187

Radiation from an emitter revolving around a magnetized non-rotating black hole

One of the methods of study of black holes in astrophysics is based on broadening of the spectrum of radiation of ionized Iron atoms. The line K$\\alpha$ associated with Iron emission at 6.4 keV is very narrow. If such an ion is revolving around a black hole, this line is effectively broadened as a result of the Doppler and gravitational redshift effects. The profile of the broaden spectrum contains information about the gravitational field of the black hole. In the presence of a regular magnetic field in the vicinity of a black holes the characteristics of the motion of charged ions are modified. In particular, their innermost stable circular orbits become closer to the horizon. The purpose of this work is to study how this effect modifies the spectrum broadening of lines emitted by such an ion. Our final goal is to analyze whether the change of the spectrum profiles can give us information about the magnetic field in the black hole vicinity.

Valeri P. Frolov; Andrey A. Shoom; Christos Tzounis

2014-05-19T23:59:59.000Z

188

Locking Information in Black Holes

Science Journals Connector (OSTI)

We show that a central presumption in the debate over black-hole information loss is incorrect. Ensuring that information not escape during evaporation does not require that it all remain trapped until the final stage of the process. Using the recent quantum information-theoretic result of locking, we show that the amount of information that must remain can be very small, even as the amount already radiated is negligible. Information need not be additive: A small system can lock a large amount of information, making it inaccessible. Only if the set of initial states is restricted can information leak.

John A. Smolin and Jonathan Oppenheim

2006-02-28T23:59:59.000Z

189

Dynamics of oscillating relativistic tori around Kerr black holes

Science Journals Connector (OSTI)

......angular momentum discs around Schwarzschild black holes, namely that...transmission of the signal recycling mirror (Shoemaker 2004)]. This...angular momentum discs around Schwarzschild black holes were considered...accretion solution on to a Schwarzschild black hole (Michel 1972......

Olindo Zanotti; José A. Font; Luciano Rezzolla; Pedro J. Montero

2005-02-01T23:59:59.000Z

190

Maximal spin and energy conversion efficiency in a symbiotic system of black hole, disk and jet

We study a combined model of black hole - accretion disk - magnetosphere - jet symbiosis, applicable for supermassive black holes. We quantify the mass and spin evolution and we analyze how the limiting value of the spin parameter and the conversion efficiency of accreted mass into radiation depend on the interplay of electromagnetic radiation reaction, magnetosphere characteristics and truncation radius of radiation. The dominant effect comes from the closed magnetic field line region, which reduces the spin limit to values ~0.89 (instead ~0.99 in its absence). Therefore observations on black hole spins could favour or disfavour the existence of the closed magnetic field line region (or its coupling to the disk). We also find that the suppression of radiation from the innermost part of the accretion disk, inferred from observations, and a collimated jet both increase the spin limit and the energy conversion efficiency.

Zoltán Kovács; László Á. Gergely; Peter L. Biermann

2010-07-24T23:59:59.000Z

191

Particle-hole symmetry broken pseudogap in high temperature superconductors

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Particle-hole symmetry broken pseudogap in Particle-hole symmetry broken pseudogap in high temperature superconductors High-temperature (Tc) superconductivity is one of the most important topics in condensed matter physics. Despite extensive studies over more than two decades, the microscopic mechanism of high temperature superconductivity still remains elusive due to many unconventional properties that are not well understood. Among them, the most mysterious behavior of high-Tc superconductor is the nature of so called "pseudogap", which has been a focus of the field for many years. In conventional superconductors, a gap exists in the energy absorption spectrum only below Tc, corresponding to the energy price to pay for breaking a Cooper pair of electrons. In high-Tc cuprate superconductors, an energy gap called the pseudogap exists above Tc but below T*, and is controversially attributed either to pre-formed superconducting pairs or to competing phases. Recently, by carefully studying the "symmetry" of the gap, researchers Makoto Hashimoto and Rui-Hua He, along with their co-workers in Prof. Zhi-Xun Shen's group at Stanford University, have found crucial evidence suggesting that the particle-hole symmetry required by superconductivity is broken in the pseudogap state.

192

Ultrafast Core-Hole Induced Dynamics in Water

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ultrafast Core-Hole Induced Dynamics in Water Print Ultrafast Core-Hole Induced Dynamics in Water Print A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems 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 water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

193

Ultrafast Core-Hole Induced Dynamics in Water

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ultrafast Core-Hole Induced Dynamics in Water Print Ultrafast Core-Hole Induced Dynamics in Water Print A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems 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 water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

194

Ultrafast Core-Hole Induced Dynamics in Water

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ultrafast Core-Hole Induced Dynamics in Water Print Ultrafast Core-Hole Induced Dynamics in Water Print A thorough understanding of the chemical processes that are initiated when radiation interacts with aqueous systems 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 water molecule sets off motions that can affect bonding configurations, which in turn affect subsequent chemical-reaction pathways. However, it is a fundamental challenge for the radiation chemistry community to unravel the early time dynamics of electronically excited states in water because their short (femtosecond) time scales are difficult to access directly with pump-probe measurements. Using a combination of isotope substitution experiments and molecular dynamics simulations, researchers from Sweden, Germany, and the U.S. have shown that the ultrafast (0- to 10-fs) dissociation dynamics of liquid water can be successfully probed with x-ray emission spectroscopy.

195

Backdraft: String Creation in an Old Schwarzschild Black Hole

We analyze string production in the background of a Schwarzschild black hole, after developing first quantized methods which capture string-theoretic nonadiabatic effects which can exceed naive extrapolations of effective field theory. Late-time infalling observers are strongly boosted in the near horizon region relative to early observers and formation matter. In the presence of large boosts in flat spacetime, known string and D-brane scattering processes exhibit enhanced string production, even for large impact parameter. This suggests the possibility that the nonadiabatic dynamics required to realize the firewall proposal of AMPS occurs for old black holes, with the late-time observer catalyzing the effect. After setting up this dynamical thought experiment, we focus on a specific case: the production of open strings stretched D-particles, at least one of which falls in late (playing the role of a late time observer). For relatively boosted D-branes, we precisely recover earlier results of Bachas, McAllister and Mitra which we generalize to brane trajectories in the black hole geometry. For two classes of late-time probes, we find a regime of significant non-adiabaticity by horizon crossing, assessing its dependence on the boost in each case. Closed string probes, as well as additional effects in D-brane scattering, may produce other significant non-adiabatic effects depending on the boost, something we leave for further work.

Eva Silverstein

2014-02-21T23:59:59.000Z

196

The scattering matrix approach for the quantum black hole, an overview

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.

G. 't Hooft

1996-07-09T23:59:59.000Z

197

Category:Thermal Gradient Holes | Open Energy Information

in category "Thermal Gradient Holes" This category contains only the following page. T Thermal Gradient Holes Retrieved from "http:en.openei.orgwindex.php?titleCategory:T...

198

T-623: HP Business Availability Center Input Validation Hole...

Broader source: Energy.gov (indexed) [DOE]

Business Availability Center Input Validation Hole Permits Cross-Site Scripting Attacks T-623: HP Business Availability Center Input Validation Hole Permits Cross-Site Scripting...

199

Three Hydrogen Bond Donor Catalysts: Oxyanion Hole Mimics and...

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hydrogen Bond Donor Catalysts: Oxyanion Hole Mimics and Transition State Analogues. Three Hydrogen Bond Donor Catalysts: Oxyanion Hole Mimics and Transition State Analogues....

200

Black hole foraging: feedback drives feeding

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 towards 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 (i) the formation and maintenance of a roughly toroidal distribution of obscuring matter near the hole; (ii) random orientations of successive accretion disk episodes; (iii) the possibility of rapid SMBH growth; (iv) tidal disruption of stars and close binaries formed from infalling gas, resulting in visible fl...

Dehnen, Walter

2013-01-01T23:59:59.000Z

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We encourage you to perform a real-time search of NLE

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201

Magnetic field outflows from active galactic nuclei

Science Journals Connector (OSTI)

We examine several models of injecting magnetic fields into clusters of galaxies from active galactic nuclei, which are the powerful outflows associated with supermassive black holes in the centers of clusters. Shown are magnetic field lines after six ... Keywords: scientific visualization

David Pugmire; Paul Sutter; Paul Ricker; Hsiang-Yi (Karen) Yang; George Foreman

2011-11-01T23:59:59.000Z

202

$P-V$ criticality of AdS black hole in the Einstein-Maxwell-power-Yang-Mills gravity

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.

Ming Zhang; Zhan-Ying Yang; De-Cheng Zou; Wei Xu; Rui-Hong Yue

2014-12-03T23:59:59.000Z

203

Use of Slim Holes for Geothermal Reservoir Assessment: An Update

Production and injection data from slim holes and large-diameter wells in three (3) geothermal fields (Oguni, Sumikawa, Steamboat Hills) were examined to determine the effect of borehole diameter (1) on the discharge rate and (2) on the productivity/injectivity indices. For boreholes with liquid feedzones, maximum discharge rates scale with diameter according to a relationship previously derived by Pritchett. The latter scaling rule does not apply to discharge data for boreholes with two-phase feedzones. Data from Oguni and Sumikawa geothermal fields indicate that the productivity (for boreholes with liquid feeds) and injectivity indices are more or less equal. The injectivity indices for Sumikawa boreholes are essentially independent of borehole diameter. The latter result is at variance with Oguni data; both the productivity and injectivity indices for Oguni boreholes display a strong variation with borehole diameter. Based on the discharge and injection data from these three geothermal fields, the flow rate of large-diameter production wells with liquid feedzones can be predicted using data from slim holes.

Garg, S.K.; Combs, J.; Goranson, C.

1995-01-01T23:59:59.000Z

204

Interacting spins and holes in zigzag edge nanographene

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.

Dutta, Sudipta; Wakabayashi, Katsunori [International Center for Materials Nanoarchitechtonics (WPI-MANA) National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki - 305-0044 (Japan)

2013-12-04T23:59:59.000Z

205

Kappa - Poincare dispersion relations and the black hole radiation

Following the methods developed by Corley and Jacobson, we consider qualitatively the issue of Hawking radiation in the case when the dispersion relation is dictated by quantum kappa-Poincare algebra. This relation corresponds to field equations that are non-local in time, and, depending on the sign of the parameter kappa, to sub- or superluminal signal propagation. We also derive the conserved inner product, that can be used to count modes, and therefore to obtain the spectrum of black hole radiation in this case.

A. Blaut; J. Kowalski-Glikman; D. Nowak-Szczepaniak

2001-08-28T23:59:59.000Z

206

Black Hole Formation and Classicalization in Ultra-Planckian 2 -> N Scattering

We establish a connection between the ultra-Planckian scattering amplitudes in field and string theory and unitarization by black hole formation in these scattering processes. Using as a guideline an explicit microscopic theory in which the black hole represents a bound-state of many soft gravitons at the quantum critical point, we were able to identify and compute a set of perturbative amplitudes relevant for black hole formation. These are the tree-level N-graviton scattering S-matrix elements in a kinematical regime (called classicalization limit) where the two incoming ultra-Planckian gravitons produce a large number N of soft gravitons. We compute these amplitudes by using the Kawai-Lewellen-Tye relations, as well as scattering equations and string theory techniques. We discover that this limit reveals the key features of the microscopic corpuscular black hole N-portrait. In particular, the perturbative suppression factor of a N-graviton final state, derived from the amplitude, matches the non-perturbative black hole entropy when N reaches the quantum criticality value, whereas final states with different value of N are either suppressed or excluded by non-perturbative corpuscular physics. Thus we identify the microscopic reason behind the black hole dominance over other final states including non-black hole classical object. In the parameterization of the classicalization limit the scattering equations can be solved exactly allowing us to obtain closed expressions for the high-energy limit of the open and closed superstring tree-level scattering amplitudes for a generic number N of external legs. We demonstrate matching and complementarity between the string theory and field theory in different large-s and large-N regimes.

G. Dvali; C. Gomez; R. S. Isermann; D. Lust; S. Stieberger

2015-02-07T23:59:59.000Z

207

A Dialogue of Multipoles: Matched Asymptotic Expansion for Caged Black Holes

No analytic solution is known to date for a black hole in a compact dimension. We develop an analytic perturbation theory where the small parameter is the size of the black hole relative to the size of the compact dimension. We set up a general procedure for an arbitrary order in the perturbation series based on an asymptotic matched expansion between two coordinate patches: the near horizon zone and the asymptotic zone. The procedure is ordinary perturbation expansion in each zone, where additionally some boundary data comes from the other zone, and so the procedure alternates between the zones. It can be viewed as a dialogue of multipoles where the black hole changes its shape (mass multipoles) in response to the field (multipoles) created by its periodic "mirrors", and that in turn changes its field and so on. We present the leading correction to the full metric including the first correction to the area-temperature relation, the leading term for black hole eccentricity and the "Archimedes effect". The next order corrections will appear in a sequel. On the way we determine independently the static perturbations of the Schwarzschild black hole in dimension d>=5, where the system of equations can be reduced to "a master equation" - a single ordinary differential equation. The solutions are hypergeometric functions which in some cases reduce to polynomials.

Dan Gorbonos; Barak Kol

2004-06-01T23:59:59.000Z

208

Solar cycle changes in coronal holes and space weather cycles J. G. Luhmann,1

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

California at Berkeley, University of

209

Kerr-AdS Black Holes and Force-Free Magnetospheres

We obtain analogs of the Blandford-Znajek split monopole solution for force-free magnetospheres around a slowly rotating Kerr-AdS black hole. For small black holes, we find an analytic solution to first order in the ratio of horizon radius to AdS scale, $r_H/l$, which exhibits a radial Poynting flux and for $r_H/l \\rightarrow 0$ smoothly approaches the Blandford-Znajek configuration in an asymptotically flat Kerr background. However, for large Kerr-AdS black holes with $r_H/l > 1$, namely those for which the bulk black hole holographically describes the thermodynamics of a strongly-interacting boundary field theory, the existence of a globally well-defined timelike Killing vector external to the horizon suggests the absence of energy extraction through the Blandford-Znajek process. In this regime, we find that at least for slow rotation the force-free solution still exists but exhibits a range of angular velocities for the field lines, corresponding to the freedom in the dual field theory to rotate a magnetic field through a neutral plasma. As a byproduct of this work, we also obtain an analytic solution for a rotating monopole magnetosphere in pure AdS, analogous to the Michel solution in flat space.

Xun Wang; Adam Ritz

2014-02-06T23:59:59.000Z

210

Black holes in the tensor-vector-scalar theory of gravity and their thermodynamics

Tensor-vector-scalar (TeVeS) theory, a relativistic theory of gravity, was designed to provide a basis for the modified Newtonian dynamics. Since TeVeS differs from general relativity (e.g., it has two metrics, an Einstein metric and a physical metric), black hole solutions of it would be valuable for a number of endeavors ranging from astrophysical modeling to investigations into the interrelation between gravity and thermodynamics. Giannios has recently found a TeVeS analogue of the Schwarzschild black hole solution. We proceed further with the program by analytically solving the TeVeS equations for a static spherically symmetric and asymptotically flat system of electromagnetic and gravity fields. We show that one solution is provided by the Reissner-Nordstroem metric as physical metric, the TeVeS vector field pointing in the time direction, and a TeVeS scalar field positive everywhere (the last feature protects from superluminal propagation of disturbances in the fields). We work out black hole thermodynamics in TeVeS using the physical metric; black hole entropy, temperature, and electric potential turn out to be identical to those in general relativity. We find it inconsistent to base thermodynamics on the Einstein metric. In light of this, we reconsider the Dubovsky-Sibiryakov scenario for violating the second law of thermodynamics in theories with Lorentz symmetry violation.

Sagi, Eva; Bekenstein, Jacob D. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2008-01-15T23:59:59.000Z

211

Black Hole Evaporation in an Expanding Universe

We calculate the quantum radiation power of black holes which are asymptotic to the Einstein-de Sitter universe at spatial and null infinities. We consider two limiting mass accretion scenarios, no accretion and significant accretion. We find that the radiation power strongly depends on not only the asymptotic condition but also the mass accretion scenario. For the no accretion case, we consider the Einstein-Straus solution, where a black hole of constant mass resides in the dust Friedmann universe. We find negative cosmological correction besides the expected redshift factor. This is given in terms of the cubic root of ratio in size of the black hole to the cosmological horizon, so that it is currently of order $10^{-5} (M/10^{6}M_{\\odot})^{1/3} (t/14 {Gyr})^{-1/3}$ but could have been significant at the formation epoch of primordial black holes. Due to the cosmological effects, this black hole has not settled down to an equilibrium state. This cosmological correction may be interpreted in an analogy with the radiation from a moving mirror in a flat spacetime. For the significant accretion case, we consider the Sultana-Dyer solution, where a black hole tends to increase its mass in proportion to the cosmological scale factor. In this model, we find that the radiation power is apparently the same as the Hawking radiation from the Schwarzschild black hole of which mass is that of the growing mass at each moment. Hence, the energy loss rate decreases and tends to vanish as time proceeds. Consequently, the energy loss due to evaporation is insignificant compared to huge mass accretion onto the black hole. Based on this model, we propose a definition of quasi-equilibrium temperature for general conformal stationary black holes.

Hiromi Saida; Tomohiro Harada; Hideki Maeda

2007-05-28T23:59:59.000Z

212

Slim Holes for Small Power Plants

Geothermal research study at Sandia National Laboratories has conducted a program in slimhole drilling research since 1992. Although our original interest focused on slim holes as an exploration method, it has also become apparent that they have substantial potential for driving small-scale, off-grid power plants. This paper summarizes Sandia's slim-hole research program, describes technology used in a ''typical'' slimhole drilling project, presents an evaluation of using slim holes for small power plants, and lists some of the research topics that deserve further investigation.

Finger, John T.

1999-08-06T23:59:59.000Z

213

Some remarks on black hole thermodynamics

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.

R. Y. Chiao

2010-12-27T23:59:59.000Z

214

Method of determining interwell oil field fluid saturation distribution

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.

Donaldson, Erle C. (Bartlesville, OK); Sutterfield, F. Dexter (Bartlesville, OK)

1981-01-01T23:59:59.000Z

215

The black hole challenge in Randall-Sundrum II model

Models postulating the existence of additional spacelike dimensions of macroscopic or even infinite size, while viewing our observable universe as merely a 3-brane living in a higher-dimensional bulk were a major breakthrough when proposed some 15 years ago. The most interesting among them both in terms of elegance of the setup and of the richness of the emerging phenomenology is the Randall-Sundrum II model where one infinite extra spacelike dimension is considered with an AdS topology, characterized by the warping effect caused by the presence of a negative cosmological constant in the bulk. A major drawback of this model is that despite numerous efforts no line element has ever been found that could describe a stable, regular, realistic black hole. Finding a smoothly behaved such solution supported by the presence of some more or less conventional fields either in the bulk and/or on the brane is the core of the black hole challenge. After a comprehensive presentation of the details of the model and the analysis of the significance and the utility of getting a specific analytic black hole solution, several (unsuccessful) analytic and numerical approaches to the problem developed over the years are presented with some discussion about their results. The chapter closes with the latest numerical results that actually consists a major advancement in the effort to address the challenge, the presentation of the most recent analytic work trying (and unfortunately failing) to build a solution assuming the existence of unconventional scalar fields and some ideas about the routes the forthcoming analytic approaches should explore.

Nikolaos D. Pappas

2014-09-02T23:59:59.000Z

216

Binary Black Hole Accretion Flows From a Misaligned Circumbinary Disk

Science Journals Connector (OSTI)

......mass-accretion-rate variation per binary...because each black hole passes across the circumbinary...mass-accretion-rate variation per binary...holes|black hole physics|Galaxies: nuclei...because each black hole passes across the circumbinary...the mass accretion rates is also independent......

Kimitake Hayasaki; Hideki Saito; Shin Mineshige

2013-08-25T23:59:59.000Z

217

(1) Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA(1) Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA (2) Harvard Medical School, Boston, MA 02114 USA(2) Harvard Medical School, Boston, MA 02114 USA (3) Section on Auditory Mechanics, NIDCD

218

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ports have the shape of elliptical cones and are cut via wire Electro-Discharge Machining (EDM). Narrow cooling holes are needed parallel to the axis of the coil and...

219

Observation of the Kondo effect in a spin-3/2 hole quantum dot

We report the observation of the Kondo effect in a spin-3/2 hole quantum dot formed near pinch-off in a GaAs quantum wire. We clearly observe two distinctive hallmarks of quantum dot Kondo physics. First, the zero-bias peak in the differential conductance splits an in-plane magnetic field and the splitting is independent of gate voltage. Second, the splitting rate is twice as large as that for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.

Klochan, O.; Micolich, A. P.; Hamilton, A. R. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Trunov, K.; Reuter, D.; Wieck, A. D. [Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

2013-12-04T23:59:59.000Z

220

Klein-Gordon equation and Hawking radiation in the dyon black hole with a cosmic string

Charged massive scalar particles are considered in the gravitational and electromagnetic field produced by a dyonic black hole with a cosmic string along the axis of symmetry. Exact solutions of both angular and radial parts of the covariant Klein-Gordon equation in this background are obtained, and are given in terms of the confluent Heun functions. We emphasize the role of the presence of the cosmic string in these solutions. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation spectrum and the energy flux.

Vieira, H S; Silva, G V

2015-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

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We encourage you to perform a real-time search of NLE

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221

Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole

We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization.

Myung, Yun Soo [Institute of Basic Science and School of Computer Aided Science Inje University, Gimhae 621-749 (Korea, Republic of)

2008-05-15T23:59:59.000Z

222

Thermodynamics of Schwarzschild-de Sitter black hole: thermal stability of Nariai black hole

We study thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization, and does not favor the Bousso-Hawking normalization.

Yun Soo Myung

2007-12-20T23:59:59.000Z

223

Phase transitions and Geometrothermodynamics of Regular black holes

In this paper we study the thermodynamics and state space geometry of regular black hole solutions such as Bardeen black hole, Ay\\'{o}n-Beato and Garc\\'{i}a black hole, Hayward black hole and Berej-Matyjasek-Trynieki-Wornowicz black hole. We find that all these black holes show second order thermodynamic phase transitions(SOTPT) by observing discontinuities in heat capacity-entropy graphs as well as the cusp type double point in free energy-temperature graph. Using the formulation of geometrothermodynamics we again find the singularities in the heat capacity of the black holes by calculating the curvature scalar of the Legendre invariant metric.

R. Tharanath; Jishnu Suresh; V. C. Kuriakose

2014-06-16T23:59:59.000Z

224

Observing another universe through ringholes and Klein-bottle holes

Science Journals Connector (OSTI)

It is argued that whereas the Shatskiy single rings produced by the gravitational inner field of a spherically symmetric wormhole and the concentric double Einstein rings generated by a toroidal ringhole could not be used without some uncertainty to identify the presence of such tunnelings in the universe or the existence of a parallel universe, the image which the inner gravitational field of a nonorientable Klein-bottle hole tunneling would leave by lensing a single luminous source is that of a truncated double spiral, which is a signature that cannot be attributed to any other single or composite astronomical object in whichever universe it may be placed. In this report we argue some more reasons to predict that such a signature would imply the discovery of one such nonorientable tunneling in our or other universe. After all, a nonorientable Klein-bottle hole is also a perfectly valid solution to the Einstein equations, and the stuff which would make it feasible is becoming more and more familiar in cosmology.

Pedro F. González-Díaz and Ana Alonso-Serrano

2011-07-20T23:59:59.000Z

225

Conserved quantities in a black hole collision

The Newman-Penrose constants of the spacetime corresponding to the development of the Brill-Lindquist initial data are calculated by making use of a particular representation of spatial infinity due to H. Friedrich. The Brill-Lindquist initial data set represents the head-on collision of two non-rotating black holes. In this case one non-zero constant is obtained. Its value is given in terms of the product of the individual masses of the black holes and the square of a distance parameter separating the two black holes. This constant retains its value all along null infinity, and therefore it provides information about the late time evolution of the collision process. In particular, it is argued that the magnitude of the constants provides information about the amount of residual radiation contained in the spacetime after the collision of the black holes.

S. Dain; J. A. Valiente-Kroon

2001-05-28T23:59:59.000Z

226

Energy of 4-Dimensional Black Hole, etc

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.

Dmitriy Palatnik

2011-07-18T23:59:59.000Z

227

Horizon Operator Approach to Black Hole Quantization

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\

G. 't Hooft

1994-02-21T23:59:59.000Z

228

Stimulated Raman scattering from free holes in p-type indium antimonide

Science Journals Connector (OSTI)

Stimulated Raman scattering from photoexcited holes at magnetic fields up to 68 kG in p-InSb is described. Experiments varying excitation wavelength, magnetic field, polarization, and sample orientation are discussed. A comparison of the experimental results with the latest valence-band calculations allows the identification of the energy levels involved in the scattering process. For sample orientation H???100?, the initial state is the valence-band Landau level ALH 101+31 and the final state is BHH 313-31. ALH, BLH are the "light hole" ladders (approximate spin M=+32 and M=-32, respectively). AHH, BHH are the "heavy hole" ladders (approximate spin M=-12 and M=+12, respectively). For the orientation H???111? initial state and final state are BLH 000+ and AHH 32O+, respectively. The holes involved in this Raman scattering process always have a nonzero momentum along the direction of the magnetic field (kH?0). The largest Raman shift we measured was about 2.7 cm-1.

R. Ebert, H. Pascher, and H. G. Häfele

1981-06-15T23:59:59.000Z

229

Jordan Algebras and Extremal Black Holes

We review various properties of the exceptional Euclidean Jordan algebra of degree three. Euclidean Jordan algebras of degree three and their corresponding Freudenthal triple systems were recently shown to be intimately related to extremal black holes in N=2, d=4 homogeneous supergravities. Using a novel type of eigenvalue problem with eigenmatrix solutions, we elucidate the rich matrix geometry underlying the exceptional N=2, d=4 homogeneous supergravity and explore the relations to extremal black holes.

Michael Rios

2007-03-27T23:59:59.000Z

230

Black hole entropy and higher curvature interactions

Science Journals Connector (OSTI)

A general formula for the entropy of stationary black holes in Lovelock higher-curvature gravity theories is obtained by integrating the first law of black hole mechanics, which is derived by Hamiltonian methods. The entropy is not simply one quarter of the surface area of the horizon, but also includes a sum of intrinsic curvature invariants integrated over a cross section of the horizon.

Ted Jacobson and Robert C. Myers

1993-06-14T23:59:59.000Z

231

Mutiny at the white-hole district

The white-hole sector of Kruskal's solution is almost never used in physical applications. However, it might contain the solution to many of the problems associated with gravitational collapse and evaporation. This essay tries to draw attention to some bouncing geometries that make a democratic use of the black- and white-hole sectors. We will argue that these types of behaviour could be perfectly natural in some approaches to the next physical level beyond classical general relativity.

Carlos Barceló; Raúl Carballo-Rubio; Luis J. Garay

2014-07-05T23:59:59.000Z

232

Thermodynamics and evaporation of the noncommutative black hole

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.

Yun Soo Myung; Yong-Wan Kim; Young-Jai Park

2006-11-24T23:59:59.000Z

233

Moving Mirrors, Black Holes, Hawking Radiation and All That

In this talk I show how to canonically quantize a massless scalar field in the background of a Schwarzschild black hole in Lema\\^itre coordinates and then present a simplified derivation of Hawking radiation based upon this procedure. The key result of quantization procedure is that the Hamiltonian of the system is explicitly time dependent and so problem is intrinsically non-static. From this it follows that, although a unitary time-development operator exists, it is not useful to talk about vacuum states; rather, one should focus attention on steady state phenomena such as the Hawking radiation. In order to clarify the approximations used to study this problem I begin by discussing the related problem of the massless scalar field theory calculated in the presence of a moving mirror.

Marvin Weinstein

2001-11-09T23:59:59.000Z

234

Moving Mirrors, Black Holes, Hawking Radiation and All That

In this talk I show how to canonically quantize a massless scalar field in the background of a Schwarzschild black hole in Lema\\^itre coordinates and then present a simplified derivation of Hawking radiation based upon this procedure. The key result of quantization procedure is that the Hamiltonian of the system is explicitly time dependent and so problem is intrinsically non-static. From this it follows that, although a unitary time-development operator exists, it is not useful to talk about vacuum states; rather, one should focus attention on steady state phenomena such as the Hawking radiation. In order to clarify the approximations used to study this problem I begin by discussing the related problem of the massless scalar field theory calculated in the presence of a moving mirror.

Weinstein, M A

2002-01-01T23:59:59.000Z

235

Moving Mirrors, Black Holes, Hawking Radiation and All That

In this talk I show how, in Lemaitre coordinates, one can canonically quantize a massless scalar field in the background of a Schwarzschild black hole and then show how this leads to a simplified derivation of Hawking radiation. The key result of the canonical quantization procedure is that the Hamiltonian of the system is explicitly time dependent, which immediately shows that the problem is intrinsically non-static and that, although a unitary time-development operator exists, it is not useful to talk about eigenstates. Rather, one should deal with the Heisenberg equations of motion and focus attention on steady state phenomena, such as the Hawking radiation. In order to clarify the procedure used to solve the Heisenberg equations I first discuss the related problem of the massless scalar field theory calculated in the presence of a moving mirror.

Weinstein, Marvin

2001-11-08T23:59:59.000Z

236

Electrical resistance of metallized via?holes

Science Journals Connector (OSTI)

The resistance of a via?hole laser?drilled through an alumina substrate depends on the hole geometry the type of probe the deposition technique and the properties of the film. If the walls of the hole constitute a truncated cone the resistance is R s/?[ln(d 2/d 1)]{1/4 + [h/(d 2 ? d 1)]2}1/2 where R s is the sheet resistance h is the substrate thickness and d 1 and d 2 are the diameters. Increasing the larger diameter helps by (a) reducing the rim?to?rim resistance (b) reducing the ’’spreading’’ resistance and (c) making the walls more accessible for metallization. A four?point probe on the other hand measures the rim?to?rim resistance as approximately (R s/?) ln cosh (h/d) where d is an average diameter. If the hole is partially bare the four?point reading will depend on probe orientation. A comparison of calculation and measurement indicates R s in the hole to be between two and forty times R s outside depending on the thickness. Electrical probing of broken?open holes showed this to be due to thickness differences not roughness or ledge resistance.

Peter M. Hall

1975-01-01T23:59:59.000Z

237

Initial data for black hole evolutions

We discuss the initial value problem of general relativity in its recently unified Lagrangian and Hamiltonian pictures and present a multi-domain pseudo-spectral collocation method to solve the resulting coupled nonlinear partial differential equations. Using this code, we explore several approaches to construct initial data sets containing one or two black holes: We compute quasi-circular orbits for spinning equal mass black holes and unequal mass (nonspinning) black holes using the effective potential method with Bowen-York extrinsic curvature. We compare initial data sets resulting from different decompositions, and from different choices of the conformal metric with each other. Furthermore, we use the quasi-equilibrium method to construct initial data for single black holes and for binary black holes in quasi-circular orbits. We investigate these binary black hole data sets and examine the limits of large mass-ratio and wide separation. Finally, we propose a new method for constructing spacetimes with superposed gravitational waves of possibly very large amplitude.

Harald P. Pfeiffer

2005-10-04T23:59:59.000Z

238

Do black holes really explode?

Science Journals Connector (OSTI)

... implies that emission of massless particles continues to occur when the static limit of a Schwarzschild field is an exceedingly good approximation. It is not therefore clear what mechanism could ...

P. C. W. DAVIES; J. G. TAYLOR

1974-07-05T23:59:59.000Z

239

Gödel black hole, closed timelike horizon, and the study of particle emissions

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.

Sourav Bhattacharya; Anirban Saha

2010-07-22T23:59:59.000Z

240

Critical behaviors of black holes in the Einstein-Maxwell gravity with conformal anomaly

We study $P-V$ critical behavior of 4-dimensional AdS black hole in the Einstein-Maxwell gravity with conformal anomaly by treating the cosmological constant as a variable related to the thermodynamic pressure. It shows that there is no phase transition if taking $k=0$ or -1. When the charge $q_1$ of conformal field and the coefficient $\\alpha$ satisfy a certain relation, the Van der Waal like phase transition for the spherical black hole can occur in case of the temperature is lower than the small critical temperature or higher than the large one. We also evaluate the critical exponents of the phase transitions and find that the thermodynamic exponents associated with this 4-dimensional AdS black hole coincide with those of the van der Waals fluid.

Zhang, Ming; Yang, Zhan-Ying

2014-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

241

Slim Holes At International Geothermal Area, Japan (Combs, Et Al., 1999) |

Japan (Combs, Et Al., 1999) Japan (Combs, Et Al., 1999) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Slim Holes At International Geothermal Area, Japan (Combs, Et Al., 1999) Exploration Activity Details Location International Geothermal Area Japan Exploration Technique Slim Holes Activity Date Usefulness useful DOE-funding Unknown Notes Based on personal relationships between Maxwell scientists and Japanese geothermal developers, production and injection data from 64 slim holes and 79 large-diameter wells (see table below) at four Japanese geothermal fields (Oguni, Sumikaw~ Takigarni, and Kirishirna) have been obtained. References Jim Combs, John T. Finger, Colin Goranson, Charles E. Hockox Jr., Ronald D. Jacobsen, Gene Polik (1999) Slimhole Handbook- Procedures And

242

Kerr black holes and time profiles of gamma-ray bursts

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.

S. McBreen; B. McBreen; L. Hanlon; F. Quilligan

2002-08-19T23:59:59.000Z

243

Microsoft Word - DOE-ID-13-053 Woods Hole EC B3-16.doc

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3 3 SECTION A. Project Title: Advances in the Recovery of Uranium from Seawater: Studies under Real Ocean Conditions - Woods Hole Oceanographic Institution SECTION B. Project Description Woods Hole Oceanographic Institution proposes to study the effectiveness of uranium adsorbents using different field testing designs. Objectives include: 1) To test the extraction efficiency of the uranium adsorbents under changing environmental conditions in a controlled laboratory setting and then in the field. 2) To collect and measure radium extracted onto manganese oxide coated fibers to quantify the volume of water passing through the uranium adsorbents. 3) To determine by field-tests the most efficient methods for collecting and the best platform to expose, in high current regimes,

244

We show that there is a classical metric satisfying the Einstein equations outside a finite spacetime region where matter collapses into a black hole and then emerges from a white hole. We compute this metric explicitly. We show how quantum theory determines the (long) time for the process to happen. A black hole can thus quantum-tunnel into a white hole. For this to happen, quantum gravity should affect the metric also in a small region outside the horizon: we show that contrary to what is commonly assumed, this is not forbidden by causality or by the semiclassical approximation, because quantum effects can pile up over a long time. This scenario alters radically the discussion on the black hole information puzzle.

Hal M. Haggard; Carlo Rovelli

2014-07-06T23:59:59.000Z

245

Black Holes and Relativistic Jets

Science Journals Connector (OSTI)

......negligible internal resistance and can drive current...that the effective resistance of the horizon is effectively...angular velocity and resistance of the load and the...radiation. Given the large electric fields present in the...describe it in terms of elementary principles. Simulations......

R. D. Blandford

2001-05-01T23:59:59.000Z

246

Black Hole Evaporation in an Expanding Universe

We calculate the quantum radiation power of black holes which are asymptotic to the Einstein-de Sitter universe at spatial and null infinities. We consider two limiting mass accretion scenarios, no accretion and significant accretion. We find that the radiation power strongly depends on not only the asymptotic condition but also the mass accretion scenario. For the no accretion case, we consider the Einstein-Straus solution, where a black hole of constant mass resides in the dust Friedmann universe. We find negative cosmological correction besides the expected redshift factor. This is given in terms of the cubic root of ratio in size of the black hole to the cosmological horizon, so that it is currently of order $10^{-5} (M/10^{6}M_{\\odot})^{1/3} (t/14 {Gyr})^{-1/3}$ but could have been significant at the formation epoch of primordial black holes. Due to the cosmological effects, this black hole has not settled down to an equilibrium state. This cosmological correction may be interpreted in an analogy with th...

Saida, Hiromi; Maeda, Hideki

2007-01-01T23:59:59.000Z

247

Is the firewall consistent? Gedanken experiments on black hole complementarity and firewall proposal

In this paper, we discuss the black hole complementarity and the firewall proposal at length. Black hole complementarity is inevitable if we assume the following five things: unitarity, entropy-area formula, existence of an information observer, semi-classical quantum field theory for an asymptotic observer, and the general relativity for an in-falling observer. However, large N rescaling and the AMPS argument show that black hole complementarity is inconsistent. To salvage the basic philosophy of the black hole complementarity, AMPS introduced a firewall around the horizon. According to large N rescaling, the firewall should be located close to the apparent horizon. We investigate the consistency of the firewall with the two critical conditions: the firewall should be near the time-like apparent horizon and it should not affect the future infinity. Concerning this, we have introduced a gravitational collapse with a false vacuum lump which can generate a spacetime structure with disconnected apparent horizons. This reveals a situation that there is a firewall outside of the event horizon, while the apparent horizon is absent. Therefore, the firewall, if it exists, not only does modify the general relativity for an in-falling observer, but also modify the semi-classical quantum field theory for an asymptotic observer.

Hwang, Dong-il; Lee, Bum-Hoon; Yeom, Dong-han, E-mail: dongil.j.hwang@gmail.com, E-mail: bhl@sogang.ac.kr, E-mail: innocent.yeom@gmail.com [Center for Quantum Spacetime, Sogang University, Seoul 121-742 (Korea, Republic of)

2013-01-01T23:59:59.000Z

248

A Dialogue of Multipoles: Matched Asymptotic Expansion for Caged Black Holes

No analytic solution is known to date for a black hole in a compact dimension. We develop an analytic perturbation theory where the small parameter is the size of the black hole relative to the size of the compact dimension. We set up a general procedure for an arbitrary order in the perturbation series based on an asymptotic matched expansion between two coordinate patches: the near horizon zone and the asymptotic zone. The procedure is ordinary perturbation expansion in each zone, where additionally some boundary data comes from the other zone, and so the procedure alternates between the zones. It can be viewed as a dialogue of multipoles where the black hole changes its shape (mass multipoles) in response to the field (multipoles) created by its periodic "mirrors", and that in turn changes its field and so on. We present the leading correction to the full metric including the first correction to the area-temperature relation, the leading term for black hole eccentricity and the "Archimedes effect". The nex...

Gorbonos, Dan; Gorbonos, Dan; Kol, Barak

2004-01-01T23:59:59.000Z

249

Injection of Electrons and Holes into Nanostructures

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Injection of Electrons and Holes into Nanostructures Injection of Electrons and Holes into Nanostructures This program targets fundamental understanding of nanoscale charge transfer processes. The proposed work draws on the strengths of the Brookhaven Chemistry Department in the areas of electron transfer experiment and theory, and extends the area of inquiry to nanoscale processes. Electron/hole injection into a wire, a nanocrystal, a nanotube or other nanostructure in solution may be brought about by light absorption, by an electron pulse (pulse radiolysis, LEAF), by a chemical reagent, or through an electrode. These processes are being studied by transient methods by following conductivity, current, but most generally, spectroscopic changes in the solutions to determine the dynamics of charge injection. The observed transient spectra can also provide values for electron-transfer coupling elements and energetics. Theoretical/computational studies can help in materials design and in the interpretation of the experimental results. The experimental systems being examined include molecular wires and metal nanoclusters.

250

Probing black holes with constellation-X

Science Journals Connector (OSTI)

Constellation-X is a premiere X-ray spectroscopy mission due to launch within the next decade. With a factor of 100 increase in sensitivity over current X-ray spectroscopy missions and an excellent energy resolution of 2 eV at 6 keV one of the prime science goals of the mission will be to observe activity near the black hole event horizon by measuring changes in the Fe K? fluorescence emission line profile and time-linked intensity changes between the line and the continuum. Detailed variability studies with Constellation-X will allow us to reconstruct “images” of the accretion disk probe the effects of strong gravity in the vicinity of black holes and measure black hole mass and spin via deconvolution of the line profile.

Kimberly A. Weaver

2001-01-01T23:59:59.000Z

251

Black Hole Complementarity in Gravity's Rainbow

We calculate the required energy for duplication of information in the context of black hole complementarity in the rainbow Schwarzschild black hole. The resultant energy can be written as the well-defined limit given by the conventional result for the vanishing rainbow parameter which characterizes the deformation of the relativistic dispersion relation in the freely falling frame. It shows that the duplication of information in quantum mechanics could be not allowed below a certain critical value of the rainbow parameter; however, it could be possible above the critical value of the rainbow parameter, so that the consistent formulation in the rainbow Schwarzschild black hole requires additional constraints or any other resolutions for the latter case.

Gim, Yongwan

2015-01-01T23:59:59.000Z

252

Nonperturbative black hole entropy and Kloosterman sums

Non-perturbative quantum corrections to supersymmetric black hole entropy often involve nontrivial number-theoretic phases called Kloosterman sums. We show how these sums can be obtained naturally from the functional integral of supergravity in asymptotically AdS_2 space for a class of black holes. They are essentially topological in origin and correspond to charge-dependent phases arising from the various gauge and gravitational Chern-Simons terms and boundary Wilson lines evaluated on Dehn-filled solid 2-torus. These corrections are essential to obtain an integer from supergravity in agreement with the quantum degeneracies, and reveal an intriguing connection between topology, number theory, and quantum gravity. We give an assessment of the current understanding of quantum entropy of black holes.

Dabholkar, Atish; Murthy, Sameer

2014-01-01T23:59:59.000Z

253

The AGN Black Hole Mass Database

The AGN Black Hole Mass Database is a compilation of all published spectroscopic reverberation-mapping studies of active galaxies. We have created a public web interface, where users may get the most up-to-date black hole masses from reverberation mapping for any particular active galactic nucleus (AGN), as well as obtain the individual measurements upon which the masses are based and the appropriate references. While the database currently focuses on the measurements necessary for black hole mass determinations, we also plan to expand it in the future to include additional useful information, such as host-galaxy characteristics. New reverberation mapping results will also be incorporated into the database as they are published in peer-refereed journals.

Bentz, Misty C

2014-01-01T23:59:59.000Z

254

Black hole chromosphere at the CERN LHC

Science Journals Connector (OSTI)

If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the CERN LHC. In this work we study the main properties of the light descendants of these black holes. We show that the emitted partons are closely spaced outside the horizon, and hence they do not fragment into hadrons in vacuum but more likely into a kind of quark-gluon plasma. Consequently, the thermal emission occurs far from the horizon, at a temperature characteristic of the QCD scale. We analyze the energy spectrum of the particles emerging from the “chromosphere,” and find that the hard hadronic jets are almost entirely suppressed. They are replaced by an isotropic distribution of soft photons and hadrons, with hundreds of particles in the GeV range. This provides a new distinctive signature for black hole events at LHC.

Luis Anchordoqui and Haim Goldberg

2003-03-26T23:59:59.000Z

255

Extremal limits and black hole entropy

Taking the extremal limit of a non-extremal Reissner-Nordstr\\"om black hole (by externally varying the mass or charge), the region between the inner and outer event horizons experiences an interesting fate -- while this region is absent in the extremal case, it does not disappear in the extremal limit but rather approaches a patch of $AdS_2\\times S^2$. In other words, the approach to extremality is not continuous, as the non-extremal Reissner-Nordstr\\"om solution splits into two spacetimes at extremality: an extremal black hole and a disconnected $AdS$ space. We suggest that the unusual nature of this limit may help in understanding the entropy of extremal black holes.

Sean M. Carroll; Matthew C. Johnson; Lisa Randall

2009-01-08T23:59:59.000Z

256

Strings as solitons & black holes as strings

Science Journals Connector (OSTI)

Supersymmetric closed string theories contain an infinite tower of BPS-saturated, oscillating, macroscopic strings in the perturbative spectrum. When these theories have dual formulations, this tower of states must exist nonperturbatively as solitons in the dual theories. We present a general class of exact solutions of low-energy supergravity that corresponds to all these states. After dimensional reduction they can be interpreted as supersymmetric black holes with a degeneracy related to the degeneracy of the string states. For example, in four dimensions we obtain a point-like solution which is asymptotic to a stationary, rotating, electrically-charged black hole with Regge-bounded angular momentum and with the usual ring-singularity replaced by a string source. This further supports the idea that the entropy of supersymmetric black holes can be understood in terms of counting of string states. We also discuss some applications of these solutions to string duality.

Atish Dabholkar; Jerome P. Gauntlett; Jeffrey A. Harvey; Daniel Waldram

1996-01-01T23:59:59.000Z

257

A Comparison of Intermediate Mass Black Hole Candidate ULXs and Stellar-Mass Black Holes

Cool thermal emission components have recently been revealed in the X-ray spectra of a small number of ultra-luminous X-ray (ULX) sources with L_X > 1 E+40 erg/s in nearby galaxies. These components can be well fitted with accretion disk models, with temperatures approximately 5-10 times lower than disk temperatures measured in stellar-mass Galactic black holes when observed in their brightest states. Because disk temperature is expected to fall with increasing black hole mass, and because the X-ray luminosity of these sources exceeds the Eddington limit for 10 Msun black holes (L_Edd = 1.3 E+39 erg/s), these sources are extremely promising intermediate-mass black hole candidates (IMBHCs). In this Letter, we directly compare the inferred disk temperatures and luminosities of these ULXs, with the disk temperatures and luminosities of a number of Galactic black holes. The sample of stellar-mass black holes was selected to include different orbital periods, companion types, inclinations, and column densities. These ULXs and stellar-mass black holes occupy distinct regions of a L_X -- kT diagram, suggesting these ULXs may harbor IMBHs. We briefly discuss the important strengths and weaknesses of this interpretation.

J. M. Miller; A. C. Fabian; M. C. Miller

2004-06-29T23:59:59.000Z

258

How red is a quantum black hole?

Radiating black holes pose a number of puzzles for semiclassical and quantum gravity. These include the transplanckian problem -- the nearly infinite energies of Hawking particles created near the horizon, and the final state of evaporation. A definitive resolution of these questions likely requires robust inputs from quantum gravity. We argue that one such input is a quantum bound on curvature. We show how this leads to an upper limit on the redshift of a Hawking emitted particle, to a maximum temperature for a black hole, and to the prediction of a Planck scale remnant.

Viqar Husain; Oliver Winkler

2005-05-30T23:59:59.000Z

259

The effects of fastener hole defects

) 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... Of Delaminated Zone Elements . . Figure 34. Enlarged View Of Area Near Hole 58 59 61 Page Figure 35. Example Finite Element Mesh Figure 36. Selected Elements For Stress Distribution Graphs . . Figure 37. Example Of o? Stress Distribution For 18 Ply Tape...

Andrews, Scot D.

2012-06-07T23:59:59.000Z

260

CHARYBDIS: A Black Hole Event Generator

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.

C. M. Harris; P. Richardson; B. R. Webber

2003-07-24T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

261

BLACK HOLE ENTROPY IN HIGHER CURVATURE GRAVITY

We discuss some recent results on black hole thermodynamics within the context of effective gravitational actions including higher-curvature interactions. Wald's derivation of the First Law demonstrates that black hole entropy can always be expressed as a local geometric density integrated over a space-like cross-section of the horizon. In certain cases, it can also be shown that these entropy expressions satisfy a Second Law. One such simple example is considered from the class of higher curvature theories where the Lagrangian consists of a polynomial in the Ricci scalar.

TED JACOBSON; GUNGWON KANG; ROBERT C. MYERS

1995-02-27T23:59:59.000Z

262

Quasilocal first law for black hole thermodynamics

Science Journals Connector (OSTI)

We first show that stationary black holes satisfy an extremely simple quasilocal form of the first law, ?E=?¯8??A, where the (quasilocal) energy E=A/(8??) and (local) surface gravity ?¯=1/?, with A the horizon area and ? is a proper length characterizing the distance to the horizon of a preferred family of quasilocal observers suitable for thermodynamical considerations. Our construction is extended to the more general framework of isolated horizons. The local surface gravity is universal. This has important implications for semiclassical considerations of black hole physics as well as for the fundamental quantum description arising in the context of loop quantum gravity.

Ernesto Frodden; Amit Ghosh; Alejandro Perez

2013-06-24T23:59:59.000Z

263

Horizon thermodynamics and gravitational field equations in Horava-Lifshitz gravity

We explore the relationship between the first law of thermodynamics and gravitational field equation at a static, spherically symmetric black hole horizon in Horava-Lifshitz theory with/without detailed balance. It turns out that as in the cases of Einstein gravity and Lovelock gravity, the gravitational field equation can be cast to a form of the first law of thermodynamics at the black hole horizon. This way we obtain the expressions for entropy and mass in terms of black hole horizon, consistent with those from other approaches. We also define a generalized Misner-Sharp energy for static, spherically symmetric spacetimes in Horava-Lifshitz theory. The generalized Misner-Sharp energy is conserved in the case without matter field, and its variation gives the first law of black hole thermodynamics at the black hole horizon.

Cai Ronggen [Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Department of Physics, Kinki University, Higashi-Osaka, Osaka 577-8502 (Japan); Ohta, Nobuyoshi [Department of Physics, Kinki University, Higashi-Osaka, Osaka 577-8502 (Japan)

2010-04-15T23:59:59.000Z

264

Steady and unsteady calibration of multi-hole probes

This thesis presents the development of a data crographics. reduction algorithm for multi-hole pressure probes. The algorithm has been developed for the reduction of calibration data from miniature non-nulling multi-hole probes in compressible...

Johansen, Espen S

1998-01-01T23:59:59.000Z

265

What is the topology of a Schwarzschild black hole?

We investigate the topology of Schwarzschild's black hole through the immersion of this space-time in spaces of higher dimension. Through the immersions of Kasner and Fronsdal we calculate the extension of the Schwarzschild's black hole.

Edmundo M. Monte

2011-11-24T23:59:59.000Z

266

Chapter 3 Topology and Uniqueness of Higher Dimensional Black Holes

Science Journals Connector (OSTI)

......of Particle and Nuclear Studies, High Energy Accelerator Research Organization...asymptotically flat vacuum black holes in...of Particle and Nuclear Studies, High Energy Accelerator Research Organization...asymptotically flat vacuum black holes in......

Daisuke Ida; Akihiro Ishibashi; Tetsuya Shiromizu

2011-06-01T23:59:59.000Z

267

Thought Experiment to resolve the Black Hole Information Paradox

We propose a combination of two mechanisms that can resolve the black hole information paradox. The first process is that the black hole shrinks by a first order transition, since we assume the entropy is discontinuous. The black hole disappears. The second type of processes conserves unitarity. We assume that within the black hole micro-reversible quantum mechanical processes take place. These are ordinary particle processes, e.g. the decay of an electron and a positron into two photons.

Kay zum Felde

2014-07-22T23:59:59.000Z

268

Dyons with potentials: Duality and black hole thermodynamics

A modified version of the double potential formalism for the electrodynamics of dyons is constructed. Besides the two vector potentials, this manifestly duality invariant formulation involves four additional potentials, scalar potentials which appear as Lagrange multipliers for the electric and magnetic Gauss constraints and potentials for the longitudinal electric and magnetic fields. In this framework, a static dyon appears as a Coulomb-like solution without string singularities. Dirac strings are needed only for the Lorentz force law, not for Maxwell's equations. The magnetic charge no longer appears as a topological conservation law but as a surface integral on a par with electric charge. The theory is generalized to curved space. As in flat space, the string singularities of dyonic black holes are resolved. As a consequence all singularities are protected by the horizon and the thermodynamics is shown to follow from standard arguments in the grand canonical ensemble.

Barnich, Glenn; Gomberoff, Andres [Physique Theorique et Mathematique, Universite Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Universidad Nacional Andres Bello, Av. Republica 239, Santiago (Chile)

2008-07-15T23:59:59.000Z

269

Graphene and the Zermelo Optical Metric of the BTZ Black Hole

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.

M. Cvetic; G. W. Gibbons

2012-02-14T23:59:59.000Z

270

The third law of thermodynamics for Kerr black holes

Science Journals Connector (OSTI)

......research-article Articles The third law of thermodynamics for Kerr black holes Isao...condition under which the third law of black-hole thermodynamics for Kerr holes is not violated...diverge to infinity as a power law for , and therefore no Kerr......

Isao Okamoto; Osamu Kaburaki

1991-05-15T23:59:59.000Z

271

Density waves in a transverse electric field

Science Journals Connector (OSTI)

In a quasi-one-dimensional conductor with an open Fermi surface, a charge- or a spin-density-wave phase can be destroyed by an electric field perpendicular to the direction of high conductivity. This mechanism, due to the breakdown of electron-hole symmetry, is very similar to the orbital destruction of superconductivity by a magnetic field, due to time-reversal symmetry.

Gilles Montambaux

1996-12-15T23:59:59.000Z

272

Geodesic study of a charged black hole

The behavior of the timelike and null geodesics of charged E. Ay$\\acute{o}$n-Beato and A. Garcia (ABG) black hole are investigated. For circular and radial geodesics, we investigate all the possible motions by plotting the effective potentials for different parameters. In conclusion, we have shown that there is no phenomenon of \\textit{superradiance} in this case.

Mehedi Kalam; Nur Farhad; Sk. Monowar Hossein

2013-03-17T23:59:59.000Z

273

Black Holes and Sub-millimeter Dimensions

Recently, a new framework for solving the hierarchy problem was proposed which does not rely on low energy supersymmetry or technicolor. The fundamental Planck mass is at a TeV and the observed weakness of gravity at long distances is due the existence of new sub-millimeter spatial dimensions. In this letter, we study how the properties of black holes are altered in these theories. Small black holes---with Schwarzschild radii smaller than the size of the new spatial dimensions---are quite different. They are bigger, colder, and longer-lived than a usual $(3+1)$-dimensional black hole of the same mass. Furthermore, they primarily decay into harmless bulk graviton modes rather than standard-model degrees of freedom. We discuss the interplay of our scenario with the holographic principle. Our results also have implications for the bounds on the spectrum of primordial black holes (PBHs) derived from the photo-dissociation of primordial nucleosynthesis products, distortion of the diffuse gamma-ray spectrum, overcl...

Argyres, Philip C; March-Russell, John David; Argyres, Philip C.; Dimopoulos, Savas; March-Russell, John

1998-01-01T23:59:59.000Z

274

Retarded cores, black holes and galaxy formation

Science Journals Connector (OSTI)

... It seems likely that elliptical galaxies contain massive 'black holes'?objects collapsed within their Schwarzschild radii?in their nuclei (see, for example, Wolfe and Burbidge2). The principal ... seems to be required to power the observed phenomena. For such a mass, the Schwarzschild radius (R s) is about 10?4 pc; for a mass of 1011 ...

John Gribbin

1974-12-06T23:59:59.000Z

275

Supermassive Black Hole Binaries: The Search Continues

Gravitationally bound supermassive black hole binaries (SBHBs) are thought to be a natural product of galactic mergers and growth of the large scale structure in the universe. They however remain observationally elusive, thus raising a question about characteristic observational signatures associated with these systems. In this conference proceeding I discuss current theoretical understanding and latest advances and prospects in observational searches for SBHBs.

Tamara Bogdanovic

2014-06-19T23:59:59.000Z

276

Chapter 8 Black Holes in Braneworld Models

Science Journals Connector (OSTI)

......to the four-dimensional Schwarzschild solution, there is no room...deformed from an ordinary Schwarzschild black hole and the radiation...gravitational attraction from its mirror image on the other side of...The attraction from the mirror image will not be larger than......

Norihiro Tanahashi; Takahiro Tanaka

2011-06-01T23:59:59.000Z

277

Science Journals Connector (OSTI)

... thin ring in a circular orbit at radius R = r GM/c2 around a Schwarzschild black hole of mass M, the two emission peaks will be at wavelengths given ... we would expect the profiles of the emission peaks at any given time to be mirror images of each other (at least on timescales longer than the orbital time). ...

R. J. TERLEVICH; J. E. PRINGLE

1979-04-19T23:59:59.000Z

278

Black Holes in 4 Nearby Radio Galaxies

We study the velocity dispersion profiles of the nuclei of NGC 1326, 2685, 5273 and 5838 in the CO first overtone band. There is evidence for a black hole (BH) in NGC 1326 and 5838. Gas is seen flowing out of the nuclear region of NGC 5273. We put upper limits on the nuclear BHs responsible for its activity and that of NGC 2685.

Mould, Jeremy; Cotter, Garret; Batt, David; Durre', Mark

2014-01-01T23:59:59.000Z

279

Remote down-hole well telemetry

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.

Briles, Scott D. (Los Alamos, NM); Neagley, Daniel L. (Albuquerque, NM); Coates, Don M. (Santa Fe, NM); Freund, Samuel M. (Los Alamos, NM)

2004-07-20T23:59:59.000Z

280

Ultrahard fluid and scalar field in the Kerr-Newman metric

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.

Babichev, E. [APC, Universite Paris 7, rue Alice Domon Duquet, 75205 Paris Cedex 13 (France); Institute for Nuclear Research of the Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow 117312 (Russian Federation); Chernov, S. [Institute for Nuclear Research of the Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow 117312 (Russian Federation); P. N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninsky Prospekt 53, 119991 Moscow (Russian Federation); Dokuchaev, V.; Eroshenko, Yu. [Institute for Nuclear Research of the Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow 117312 (Russian Federation)

2008-11-15T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

281

Scalar field collapse with negative cosmological constant

The formation of black holes or naked singularities is studied in a model in which a homogeneous time-dependent scalar field with an exponential potential couples to four dimensional gravity with negative cosmological constant. An analytic solution is derived and its consequences are discussed. The model depends only on one free parameter, which determines the equation of state and decides the fate of the spacetime. Without fine tuning the value of this parameter the collapse ends in a generic formation of a black hole or a naked singularity. The latter case violates the cosmic censorship conjecture.

R. Baier; Hiromichi Nishimura; S. A. Stricker

2014-10-13T23:59:59.000Z

282

Scalar field collapse with negative cosmological constant

The formation of black holes or naked singularities is studied in a model in which a homogeneous time-dependent scalar field with an exponential potential couples to four dimensional gravity with negative cosmological constant. An analytic solution is derived and its consequences are discussed. The model depends only on one free parameter which determines the equation of state and decides the fate of the spacetime. Depending on the value of this parameter the collapse ends in a black hole or a naked singularity. The latter case violates the cosmic censorship conjecture.

Baier, R; Stricker, S A

2014-01-01T23:59:59.000Z

283

Courts Soccer Field Swimming pool Bandeen Hall Mountain House # 3 # 2 Golf Course Security Patterson Hall.B. Scott Arena Library Centennial Theater Mc Greer Hall Pollack Hall New Johnson Science Building Dewhurst Dining Hall Champlain Regional College # 4 Mackinnon Hall Residence # 6 Memorial House Retired Faculty

284

Science Journals Connector (OSTI)

......Limit of Low Accretion Rate Li-Xin Li * * Chandra...2) the accretion rate is low, but the accretion...solutions that smoothly pass the fast critical...disks|black hole physics|magnetic fields...of a high accretion rate, or equivalently...solutions that smoothly pass the fast critical......

Li-Xin Li

2004-08-25T23:59:59.000Z

285

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

286

Hole transport in the rare-gas solids Ne, Ar, Kr, and Xe

Science Journals Connector (OSTI)

This paper reports an investigation of the drift mobility of excess holes in solid Ne, Ar, Kr, and Xe. Thin-crystal specimens (50-500 ?m thick) were grown from the liquid between parallel-plate electrodes in a chamber attached to a miniature cryostat after purification of the starting gas. As in previous work on the electron transport in rare-gas solids and liquids, an electron-beam technique was used to generate excess carriers near one of the electrodes. Holes were extracted by the applied field and their transit time was measured directly, leading to the drift mobility ?h. Close to the triple points, ?h values in the above crystals lie between 1 × 10-2 and 4 × 10-2 cm2 V-1 sec-1, several orders of magnitude lower than the corresponding electron mobilities. The form of the temperature dependence of ?h changes progressively from Xe (?h?T-1.6) to an essentially activated mobility in Ar and Ne. The experimental results have been analyzed in terms of small-polaron theory, using both the adiabatic and nonadiabatic approximations. The theory can account for the different forms of the temperature dependence and possible ranges of values for the predominant phonon energy, the polaron binding energy and the transfer energy for holes have been deduced in each case. These quantities, characterizing the hole hopping transport, vary systematically from Xe to Ne and their correlation is discussed in some detail.

P. G. Le Comber; R. J. Loveland; W. E. Spear

1975-04-15T23:59:59.000Z

287

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.

Sarica, C.; Demir, H.M.; Brill, J.P.

1996-09-01T23:59:59.000Z

288

An excision scheme for black holes in constrained evolution formulations: spherically symmetric case

Excision techniques are used in order to deal with black holes in numerical simulations of Einstein equations and consist in removing a topological sphere containing the physical singularity from the numerical domain, applying instead appropriate boundary conditions at the excised surface. In this work we present recent developments of this technique in the case of constrained formulations of Einstein equations and for spherically symmetric spacetimes. We present a new set of boundary conditions to apply to the elliptic system in the fully-constrained formalism of Bonazzola et al. (2004), at an arbitrary coordinate sphere inside the apparent horizon. Analytical properties of this system of boundary conditions are studied and, under some assumptions, an exponential convergence toward the stationary solution is exhibited for the vacuum spacetime. This is verified in numerical examples, together with the applicability in the case of the accretion of a scalar field onto a Schwarzschild black hole. We also present the successful use of the excision technique in the collapse of a neutron star to a black hole, when excision is switched on during the simulation, after the formation of the apparent horizon. This allows the accretion of matter remaining outside the excision surface and for the stable long-term evolution of the newly formed black hole.

Isabel Cordero-Carrión; Nicolas Vasset; Jérôme Novak; José Luis Jaramillo

2014-08-26T23:59:59.000Z

289

Entropy of near-extremal black holes in AdS5

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.

Simon, Joan; Balasubramanian, Vijay; de Boer, Jan; Jejjala, Vishnu; Simon, Joan

2007-07-24T23:59:59.000Z

290

We present a novel investigation into the relationship between simple estimates of magnetic flux balance and the Ne VIII Doppler velocity partitioning of a large equatorial coronal hole observed by the Solar Ultraviolet Measurements of Emitted Radiation spectrometer (SUMER) on the Solar and Heliospheric Observatory (SOHO) in November 1999. We demonstrate that a considerable fraction of the large scale Doppler velocity pattern in the coronal hole can be qualitatively described by simple measures of the local magnetic field conditions, i.e., the relative unbalance of magnetic polarities and the radial distance required to balance local flux concentrations with those of opposite polarity.

Scott W. McIntosh; Alisdair R. Davey; Scott W. McIntosh

2006-05-22T23:59:59.000Z

291

The generation of fast ion beams in the hole-boring radiation pressure acceleration by intense laser pulses has been studied for targets with different ion components. We find that the oscillation of the longitudinal electric field for accelerating ions can be effectively suppressed by using a two-ion-species target, because fast ions from a two-ion-species target are distributed into more bunches and each bunch bears less charge. Consequently, the energy spread of ion beams generated in the hole-boring radiation pressure acceleration can be greatly reduced down to 3.7% according to our numerical simulation.

Weng, S M; Sheng, Z M

2014-01-01T23:59:59.000Z

292

Relativistic simulations of black hole-neutron star coalescence: the jet emerges

We perform magnetohydrodynamic simulations in full general relativity of an initially quasiequilibrium binary black hole-neutron star on a quasicircular orbit that undergoes merger. The binary mass ratio is $3:1$, the black hole has initial spin parameter $a/m=0.75$ aligned with the orbital angular momentum, and the neutron star is modeled as an irrotational $\\Gamma=2$ polytrope. About two orbits prior to merger (at time $t=t_B$), we seed the neutron star with a dynamically weak dipolar magnetic field [${B}_{pole}\\sim 10^{14}(1.4M_\\odot/M_{\\rm NS})$ G] that extends from the stellar interior into the exterior. At $t=t_B$ the exterior is characterized by a low density atmosphere with constant plasma parameter $\\beta\\equiv P_{\\rm gas}/P_{\\rm mag}$. Varying $\\beta$ at $t_B$ in the exterior from $0.1$ to $0.01$, we find that at $\\sim 4000M \\sim 100(M_{\\rm NS}/1.4M_\\odot)$ms following the onset of accretion of tidally disrupted debris, magnetic field winding above the remnant black hole poles builds up the magnetic field sufficiently to launch a mildly relativistic, collimated outflow - an incipient jet. The duration of the accretion and the lifetime of the jet is $\\Delta t\\sim 0.5(M_{\\rm NS}/1.4M_\\odot)$s. Our simulations are the first self-consistent calculations in full general relativity that provide theoretical corroboration that mergers of black hole-neutron stars can launch jets and be the central engines that power short-hard gamma ray bursts.

Vasileios Paschalidis; Milton Ruiz; Stuart L. Shapiro

2014-10-27T23:59:59.000Z

293

Hybrid black-hole binary initial data

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.

Bruno C. Mundim; Bernard J. Kelly; Yosef Zlochower; Hiroyuki Nakano; Manuela Campanelli

2010-12-04T23:59:59.000Z

294

The high energy emission from black holes

The origin of the high energy emission (X-rays and gamma-rays) from black holes is still a matter of debate. We present new evidence that hard X-ray emission in the low/hard state may not be dominated by thermal Comptonization. We present an alternative scenario for the origin of the high energy emission that is well suited to explain the high energy emission from GRO J1655-40.

M. D. Caballero-Garcia; J. M. Miller; E. Kuulkers

2007-11-06T23:59:59.000Z

295

Black hole remnants in the early universe

Science Journals Connector (OSTI)

We consider the production of primordial micro black holes (MBH) remnants in the early Universe. These objects induce the Universe to be in a matter-dominated era before the onset of inflation. Effects of such an epoch on the CMB power spectrum are discussed and computed both analytically and numerically. By comparison with the latest observational data from the WMAP collaboration, we find that our model appears to explain the quadrupole anomaly of the CMB power spectrum.

Fabio Scardigli; Christine Gruber; Pisin Chen

2011-03-09T23:59:59.000Z

296

Hole cleaning requirements with seabed returns

size and fluid density. The least important were rotary speed, feed concentration, annulus size, and drillpipe eccentricity. They also reported that, in Newtonian fluids, transport efficiency improves with increasing viscosity; however, they noted... is set; therefore, no marine riser can be utilized. The coring occurs up to 3000 ft below the seafloor with the bit cutting an 11. 438 in. hole. The rig pumps have a maximum output of 600 gpm under normal coring operations with untreated seawater...

Nordt, David Paul

1988-01-01T23:59:59.000Z

297

Spectral hole burning for stopping light

We propose a protocol for storage and retrieval of photon wave packets in a {lambda}-type atomic medium. This protocol derives from spectral hole burning and takes advantages of the specific properties of solid-state systems at low temperature, such as rare-earth ion-doped crystals. The signal pulse is tuned to the center of the hole that has been burnt previously within the inhomogeneously broadened absorption band. The group velocity is strongly reduced, being proportional to the hole width. This way the optically carried information and energy are carried over to the off-resonance optical dipoles. Storage and retrieval are performed by conversion to and from ground-state Raman coherence by using brief {pi} pulses. The protocol exhibits some resemblance with the well-known electromagnetically induced transparency process. It also presents distinctive features such as the absence of coupling beam. In this paper we detail the various steps of the protocol, summarize the critical parameters, and theoretically examine the recovery efficiency.

Lauro, R.; Chaneliere, T.; Le Goueet, J.-L. [Laboratoire Aime Cotton, CNRS UPR3321, Universite Paris Sud, Batiment 505, Campus Universitaire, 91405 Orsay (France)

2009-05-15T23:59:59.000Z

298

Light Loop Echoes and Blinking Black Holes

Radiation emitted near a black hole reaches the observer by multiple paths; and when this radiation varies in time, the time-delays between the various paths generate a "blinking" effect in the observed light curve L(t) or its auto-correlation function xi(T)= . For the particularly important "face-on" configuration (in which the hole is viewed roughly along its spin axis, while the emission comes roughly from its equatorial plane -- e.g. from the inner edge of its accretion disk, or from the violent flash of a nearby/infalling star) we calculate the blinking in detail by computing the time delay Delta t_{j}(r,a) and magnification mu_{j}(r,a) of the jth path (j=1,2,3,...), relative to the primary path (j=0), as a function of the emission radius r and black hole spin 0

299

Dark jets in solar coronal holes

A new solar feature termed a dark jet is identified from observations of an extended solar coronal hole that was continuously monitored for over 44 hours by the EUV Imaging Spectrometer on board the Hinode spacecraft in 2011 February 8-10. Line-of-sight velocity maps derived from the coronal Fe XII $\\lambda$195.12 emission line, formed at 1.5 MK, revealed a number of large-scale, jet-like structures that showed significant blueshifts. The structures had either weak or no intensity signal in 193 A filter images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, suggesting that the jets are essentially invisible to imaging instruments. The dark jets are rooted in bright points and occur both within the coronal hole and at the quiet Sun-coronal hole boundary. They exhibit a wide range of shapes, from narrow columns to fan-shaped structures, and sometimes multiple jets are seen close together. A detailed study of one dark jet showed line-of-sight speeds increasing along the jet axis fr...

Young, Peter R

2015-01-01T23:59:59.000Z

300

Quantization of rotating linear dilaton black holes

In this paper, we firstly prove that the adiabatic invariant quantity, which is commonly used in the literature for quantizing the rotating black holes (BHs) is fallacious. We then show how its corrected form should be. The main purpose of this paper is to study the quantization of 4-dimensional rotating linear dilaton black hole (RLDBH) spacetime describing with an action, which emerges in the Einstein-Maxwell-Dilaton-Axion (EMDA) theory. The RLDBH spacetime has a non-asymptotically flat (NAF) geometry. They reduces to the linear dilaton black hole (LDBH) metric when vanishing its rotation parameter $a$. While studying its scalar perturbations, it is shown that the Schr\\"odinger-like wave equation around the event horizon reduces to a confluent hypergeometric differential equation. Then the associated complex frequencies of the quasinormal modes (QNMs) are computed. By using those QNMs in the true definition of the rotational adiabatic invariant quantity, we obtain the quantum spectra of entropy/area for the RLDBH. It is found out that both spectra are discrete and equidistant. Besides, we reveal that the quantum spectra do not depend on $a$ in spite of the QNMs are modulated by it.

I. Sakalli

2014-06-19T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

301

Gamma-ray bursts from accreting black holes in neutron star mergers

By means of three-dimensional hydrodynamic simulations with a Eulerian PPM code we investigate the formation and the properties of the accretion torus around the stellar mass black hole which originates from the merging of two neutron stars. The simulations are performed with four nested cartesian grids which allow for both a good resolution near the central black hole and a large computational volume. They include the use of a physical equation of state as well as the neutrino emission from the hot matter of the torus. The gravity of the black hole is described with a Newtonian and alternatively with a Paczynski-Wiita potential. In a post-processing step, we evaluate our models for the energy deposition by nu-nubar annihilation around the accretion torus. Our models show that nu-nubar annihilation can yield the energy to account for weak, short gamma-ray bursts, if moderate beaming is involved. In fact, the barrier of the dense baryonic gas of the torus suggests that the low-density pair-photon-plasma is beamed as axial jets into a fraction 2 delta Omega/ (4 pi) between 1/100 and 1/10 of the sky, corresponding to opening half-angles of roughly ten to several tens of degrees. Thus gamma-burst energies of 10^{50}--10^{51} erg seem within the reach of our models (if the source is interpreted as radiating isotropically), corresponding to luminosities around 10^{51} erg/s for typical burst durations of 0.1--1 s. Gravitational capture of radiation by the black hole, redshift and ray bending do not reduce the jet energy significantly. Effects associated with the Kerr character of the rapidly rotating black hole, however, could increase the gamma-burst energy considerably, and effects due to magnetic fields might even be required to get the energies for long complex gamma-ray bursts.

M. Ruffert; H. -Th. Janka

1998-09-23T23:59:59.000Z

302

Relativistic simulations of black hole-neutron star coalescence: the jet emerges

We perform magnetohydrodynamic simulations in full general relativity of an initially quasiequilibrium binary black hole-neutron star on a quasicircular orbit that undergoes merger. The binary mass ratio is $3:1$, the black hole has initial spin parameter $a/m=0.75$ aligned with the orbital angular momentum, and the neutron star is modeled as an irrotational $\\Gamma=2$ polytrope. About two orbits prior to merger (at time $t=t_B$), we seed the neutron star with a dynamically weak dipolar magnetic field [${B}_{pole}\\sim 10^{14}(1.4M_\\odot/M_{\\rm NS})$ G] that extends from the stellar interior into the exterior. At $t=t_B$ the exterior is characterized by a low density atmosphere with constant plasma parameter $\\beta\\equiv P_{\\rm gas}/P_{\\rm mag}$. Varying $\\beta$ at $t_B$ in the exterior from $0.1$ to $0.01$, we find that at $\\sim 4000M \\sim 100(M_{\\rm NS}/1.4M_\\odot)$ms following the onset of accretion of tidally disrupted debris, magnetic field winding above the remnant black hole poles builds up the magnetic...

Paschalidis, Vasileios; Shapiro, Stuart L

2014-01-01T23:59:59.000Z

303

Scanning Tunneling Macroscopy, Black Holes, and AdS/CFT Bulk Locality

We establish resolution bounds on reconstructing a bulk field from boundary data on a timelike hypersurface. If the bulk only supports propagating modes, reconstruction is complete. If the bulk also supports evanescent modes, local reconstruction is not achievable unless one has exponential precision in knowledge of the boundary data. Without exponential precision, for a Minkowski bulk, one can reconstruct a spatially coarse-grained bulk field, but only out to a depth set by the coarse-graining scale. For an asymptotically AdS bulk, reconstruction is limited to a spatial coarse-graining proper distance set by the AdS scale. AdS black holes admit evanescent modes. We study the resolution bound in the large AdS black hole background and provide a dual CFT interpretation. Our results demonstrate that, if there is a black hole of any size in the bulk, then sub-AdS bulk locality is no longer well-encoded in boundary data in terms of local CFT operators. Specifically, in order to probe the bulk on sub-AdS scales using only boundary data in terms of local operators, one must either have such data to exponential precision or make further assumptions about the bulk state.

Soo-Jong Rey; Vladimir Rosenhaus

2014-06-02T23:59:59.000Z

304

Black hole radiation in the presence of a short distance cutoff

Science Journals Connector (OSTI)

A derivation of the Hawking effect is given which avoids reference to field modes above some cutoff frequency ?c?M-1 in the free-fall frame of the black hole. To avoid reference to arbitrarily high frequencies, it is necessary to impose a boundary condition on the quantum field in a timelike region near the horizon, rather than on a (spacelike) Cauchy surface either outside the horizon or at early times before the horizon forms. Because of the nature of the horizon as an infinite redshift surface, the correct boundary condition at late times outside the horizon cannot be deduced, within the confines of a theory that applies only below the cutoff, from initial conditions prior to the formation of the hole. A boundary condition is formulated which leads to the Hawking effect in a cutoff theory. It is argued that it is possible the boundary condition is not satisfied, so that the spectrum of black hole radiation may be significantly different from that predicted by Hawking, even without the back reaction near the horizon becoming of order unity relative to the curvature.

Ted Jacobson

1993-07-15T23:59:59.000Z

305

Accretion disks around binary black holes of unequal mass: GRMHD simulations near decoupling

We report on simulations in general relativity of magnetized disks onto black hole binaries. We vary the binary mass ratio from 1:1 to 1:10 and evolve the systems when they orbit near the binary-disk decoupling radius. We compare (surface) density profiles, accretion rates (relative to a single, non-spinning black hole), variability, effective $\\alpha$-stress levels and luminosities as functions of the mass ratio. We treat the disks in two limiting regimes: rapid radiative cooling and no radiative cooling. The magnetic field lines clearly reveal jets emerging from both black hole horizons and merging into one common jet at large distances. The magnetic fields give rise to much stronger shock heating than the pure hydrodynamic flows, completely alter the disk structure, and boost accretion rates and luminosities. Accretion streams near the horizons are among the densest structures; in fact, the 1:10 no-cooling evolution results in a refilling of the cavity. The typical effective temperature in the bulk of the disk is $\\sim 10^5 (M/10^8 M_\\odot)^{-1/4} (L/L_{\\rm edd})^{1/4} {\\rm K}$ yielding characteristic thermal frequencies $\\sim 10^{15} (M/10^8 M_\\odot)^{-1/4} (L/L_{\\rm edd})^{1/4}(1+z)^{-1}{\\rm Hz} $. These systems are thus promising targets for many extragalactic optical surveys, such as LSST, WFIRST, and PanSTARRS.

Roman Gold; Vasileios Paschalidis; Zachariah B. Etienne; Stuart L. Shapiro; Harald P. Pfeiffer

2013-12-02T23:59:59.000Z

306

Black holes as self-sustained quantum states, and Hawking radiation

We employ the recently proposed formalism of the "horizon wave-function" to investigate the emergence of a horizon in models of black holes as Bose-Einstein condensates of gravitons. We start from the Klein-Gordon equation for a massless scalar (toy graviton) field coupled to a static matter current. The (spherically symmetric) classical field reproduces the Newtonian potential generated by the matter source, and the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. Assuming an attractive self-interaction that allows for bound states, one finds that (approximately) only one mode is allowed, and the system can be confined in a region of the size of the Schwarzschild radius. This radius is then shown to correspond to a proper horizon, by means of the horizon wave-function of the quantum system, with an uncertainty in size naturally related to the expected typical energy of Hawking modes. In particular, this uncertainty decreases for larger black hole mass (with larger number of light scalar quanta), in agreement with semiclassical expectations, a result which does not hold for a single very massive particle. We finally speculate that a phase transition should occur during the gravitational collapse of a star, ideally represented by a static matter current and Newtonian potential, that leads to a black hole, again ideally represented by the condensate of toy gravitons, and suggest an effective order parameter that could be used to investigate this transition.

Roberto Casadio; Andrea Giugno; Octavian Micu; Alessio Orlandi

2014-10-06T23:59:59.000Z

307

The String Landscape, Black Holes and Gravity as the Weakest Force

We conjecture a general upper bound on the strength of gravity relative to gauge forces in quantum gravity. This implies, in particular, that in a four-dimensional theory with gravity and a U(1) gauge field with gauge coupling g, there is a new ultraviolet scale Lambda=g M_{Pl}, invisible to the low-energy effective field theorist, which sets a cutoff on the validity of the effective theory. Moreover, there is some light charged particle with mass smaller than or equal to Lambda. The bound is motivated by arguments involving holography and absence of remnants, the (in) stability of black holes as well as the non-existence of global symmetries in string theory. A sharp form of the conjecture is that there are always light "elementary" electric and magnetic objects with a mass/charge ratio smaller than the corresponding ratio for macroscopic extremal black holes, allowing extremal black holes to decay. This conjecture is supported by a number of non-trivial examples in string theory. It implies the necessary presence of new physics beneath the Planck scale, not far from the GUT scale, and explains why some apparently natural models of inflation resist an embedding in string theory.

Nima Arkani-Hamed; Lubos Motl; Alberto Nicolis; Cumrun Vafa

2006-01-02T23:59:59.000Z

308

Non-linear Plasma Wake Growth of Electron Holes

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...

Hutchinson, I H; Zhou, C

2015-01-01T23:59:59.000Z

309

Black hole entanglement entropy regularized in a freely falling frame

Science Journals Connector (OSTI)

We compute the black hole horizon entanglement entropy SE for a massless scalar field, first with a hard cutoff and then with high frequency dispersion, both imposed in a frame that falls freely across the horizon. Using WKB methods, we find that SE is finite for a hard cutoff or superluminal dispersion, because the mode oscillations do not diverge at the horizon and the contribution of high transverse momenta is cut off by the angular momentum barrier. For subluminal dispersion, the entropy depends on the behavior at arbitrarily high transverse momenta. In all cases it scales with the horizon area. For the hard cutoff it is linear in the cutoff, rather than quadratic. This discrepancy from the familiar result arises from the difference between the free-fall frame and the static frame in which a cutoff is usually imposed. In the superluminal case the entropy scales with a fractional power of the cutoff that depends on the index of the dispersion relation. Implications for the possible relation between regularized entanglement entropy and the Bekenstein-Hawking entropy are discussed. An appendix provides an explicit derivation of the entangled, thermal nature of the near-horizon free-fall vacuum for a dispersive scalar field in four dimensions.

Ted Jacobson and Renaud Parentani

2007-07-13T23:59:59.000Z

310

Null geodesics and shadow of a rotating black hole in extended Chern-Simons modified gravity

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.

Amarilla, Leonardo [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque, 1900, La Plata (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, 1428, Buenos Aires (Argentina); Eiroa, Ernesto F. [Instituto de Astronomia y Fisica del Espacio, C.C. 67 Suc. 28, 1428, Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, 1428, Buenos Aires (Argentina); Giribet, Gaston [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, 1428, Buenos Aires (Argentina)

2010-06-15T23:59:59.000Z

311

Deep field observations are an essential tool to probe the cosmological evolution of galaxies. In this context, X-ray deep fields provide information about some of the most energetic cosmological objects: active galactic nuclei (AGN). Astronomers are interested in detecting sufficient numbers of AGN to probe the accretion history at high redshift. This talk gives an overview of the knowledge resulting from a highly complete soft X-ray selected sample collected with ROSAT, XMM-Newton and Chandra deep fields. The principal outcome based on X-ray luminosity functions and space density evolution studies is that low-luminosity AGN evolve in a dramatically different way from high-luminosity AGN: The most luminous quasars perform at significantly earlier cosmic times and are most numerous in a unit volume at cosmological redshift z~2. In contrast, low-luminosity AGN evolve later and their space density peaks at z~0.7. This finding is also interpreted as an anti-hierarchical growth of supermassive black holes in the Universe. Comparing this with star formation rate history studies one concludes that supermassive black holes enter the cosmic stage before the bulk of the first stars. Therefore, first solutions of the so-called hen-egg problem are suggested. Finally, status developments and expectations of ongoing and future extended observations such as the XMM-COSMOS project are highlighted.

G. Hasinger; A. Mueller

2005-10-14T23:59:59.000Z

312

K-Shell-Hole Production, Multiple-Hole Production, Charge-Transfer, and Antisymmetry

-shell electron can occur. For example, after making a K-shell hole an L-shell electron may be knocked into it, or an L-shell vacancy may be produced and the K-shell electron promoted to that vacancy in the "Fermi sea" of the target-atom orbitals, In 1973 a.... If one is working in first-order pertur- bation theory E-shell-hole production is correctly obtained by calculating the process for the K elec- tron to be lifted above the "Fermi sea" of occupied target orbitals, i.e., the other electrons play a...

Reading, John F.; Ford, A. Lewis.

1980-01-01T23:59:59.000Z

313

Mineral Test Hole Regulatory Act (Tennessee) | Department of Energy

Broader source: Energy.gov (indexed) [DOE]

Mineral Test Hole Regulatory Act (Tennessee) Mineral Test Hole Regulatory Act (Tennessee) Mineral Test Hole Regulatory Act (Tennessee) < Back Eligibility Commercial Construction Developer Fuel Distributor Industrial Installer/Contractor Investor-Owned Utility Municipal/Public Utility Utility Program Info State Tennessee Program Type Environmental Regulations Siting and Permitting Provider Tennessee Department Of Environment and Conservation The Mineral Hole Regulatory Act is applicable to any person (individual, corporation, company, association, joint venture, partnership, receiver, trustee, guardian, executor, administrator, personal representative or private organization of any kind) who wishes to drill a mineral test hole (any hole in excess of one hundred (100) feet drilled during the exploration for minerals but shall exclude auger drilling in surficial or

314

Video: Part of the 'Hole' Story (of Uranium Hexafluoride Cylinders)

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hole Story Hole Story Part of the "Hole" Story (of Uranium Hexafluoride Cylinders) Holes in the depleted Uranium Hexafluoride storage cylinders are investigated. It is shown that corrosion products cause the openings to be self-healing. View this Video in Real Player format Download free RealPlayer SP Highlights of the Video: Video 00:00 Part of the 'Hole' Story Video 00:05 One of the depleted UF6 cylinder storage lots at Portsmouth Video 00:28 48G cylinders, each containing 14 tons of depleted UF6, in storage Video 00:52 Stacked 48G cylinders Video 01:35 UF6 sealed in glass tube Video 02:01 A lifting lug of one cylinder damaging a neighboring cylinder Video 02:37 Damage to small hole cylinder from impact with a lifting lub of an adjoining cylinder

315

Articles which include chevron film cooling holes, and related processes

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.

Bunker, Ronald Scott; Lacy, Benjamin Paul

2014-12-09T23:59:59.000Z

316

Method and apparatus of assessing down-hole drilling conditions

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.

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)

2007-04-24T23:59:59.000Z

317

Hole Self-Energy Corrections in the Brueckner Theory

Science Journals Connector (OSTI)

To study corrections to hole propagators in Brueckner theory, an extension of the Hugenholtz convolution theorem is proved. An integral equation is derived for a class of Brueckner hole corrections and approximate solutions are obtained, one of which gives the usual prescription that makes holes propagate on the energy shell. The derivation shows which class of diagrams are included in this prescription and suggests that a more accurate treatment might be needed.

J. Nuttall

1966-09-23T23:59:59.000Z

318

On the Stability of Black Holes at the LHC

The eventual production of mini black holes by proton-proton collisions at the LHC is predicted by theories with large extra dimensions resolvable at the Tev scale of energies. It is expected that these black holes evaporate shortly after its production as a consequence of the Hawking radiation. We show that for theories based on the ADS/CFT correspondence, the produced black holes may have an unstable horizon, which grows proportionally to the square of the distance to the collision point.

M. D. Maia; E. M. Monte

2008-08-19T23:59:59.000Z

319

Temperature, heat flow maps and temperature gradient holes |...

Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Organization Colorado Geological Survey in Cooperation with the U.S. Department of Energy...

320

Thermal Gradient Holes At Long Valley Caldera Geothermal Area...

Date 1978 - 1985 Usefulness useful DOE-funding Unknown Exploration Basis Thermal gradient drilling also continued during this period, consisting of several holes including: The...

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

321

Core Holes At Blue Mountain Geothermal Area (Fairbank & Niggemann...

Exploration Activity Details Location Blue Mountain Geothermal Area Exploration Technique Core Holes Activity Date 2002 - 2004 Usefulness useful DOE-funding Unknown Exploration...

322

Thermal Gradient Holes At Chena Geothermal Area (EERE, 2010)...

EERE, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chena Geothermal Area (EERE, 2010) Exploration Activity...

323

Comparison of Black Hole Generators for the LHC

We compare Monte Carlo event generators dedicated to simulating the production and decay of extra-dimensional black holes at the Large Hadron Collider.

Douglas M. Gingrich

2006-10-17T23:59:59.000Z

324

A rotating black hole in the Galactic Center

Recent observations of Sgr A* give strong constraints for possible models of the physical nature of Sgr A* and suggest the presence of a massive black~hole with M0.9) accreting 10^-8.5 - 10^-7 M_sun/yr at a black~hole mass of M=2 10^6 M_sunseen almost edge on. A low mass black hole of M' together with simple scaling laws to provide an easy-to-handle test for the black hole model.

Heino Falcke; Peter L. Biermann; Wolfgang J. Duschl; Peter G. Mezger

1992-12-07T23:59:59.000Z

325

Hole doping in high temperature superconductors using the XANES technique

Hole doping in high temperature superconductors using the1994 Thallium-Based High Temperature Superconductors ed A M1994 Thallium-Based High Temperature Superconductors ed A M

Hamdan, Nasser

2012-01-01T23:59:59.000Z

326

Core Holes At Long Valley Caldera Geothermal Area (Eichelberger...

Eichelberger, Et Al., 1988) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Core Holes At Long Valley Caldera Geothermal Area (Eichelberger, Et...

327

Core Holes At Steamboat Springs Area (Warpinski, Et Al., 2004...

Steamboat Springs Area (Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Core Holes At Steamboat Springs Area (Warpinski,...

328

Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski,...

Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski, Et Al.,...

329

Core Holes At Long Valley Caldera Geothermal Area (Urban, Et...

Urban, Et Al., 1987) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Core Holes At Long Valley Caldera Geothermal Area (Urban, Et Al., 1987)...

330

Thermal Gradient Holes At Chena Geothermal Area (Erkan, Et Al...

Erkan, Et Al., 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chena Geothermal Area (Erkan, Et Al., 2007)...

331

Slim Holes At Blue Mountain Area (Warpinski, Et Al., 2002) |...

Blue Mountain Area (Warpinski, Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Slim Holes At Blue Mountain Area (Warpinski, Et Al.,...

332

Thermal Gradient Holes At Obsidian Cliff Area (Hulen, Et Al....

Obsidian Cliff Area (Hulen, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Obsidian Cliff Area (Hulen,...

333

Using the Uncharged Kerr Black Hole as a Gravitational Mirror

Science Journals Connector (OSTI)

We extend the study of the possible use of the Schwarzschild black hole as a gravitational mirror to the more general case of an...

Claes R. Cramer

1997-04-01T23:59:59.000Z

334

The first law of thermodynamics in Lifshitz black holes revisited

We obtain the mass expression of the three- and five-dimensional Lifshitz black holes by em- ploying the recently proposed quasilocal formulation of conserved charges, which is based on the off-shell extension of the ADT formalism. Our result is consistent with the first law of black hole thermodynamics and resolves the reported discrepancy between the ADT formalism and the other conventional methods. The same mass expression of Lifshitz black holes is obtained by using an- other quasilocal method by Padmanabhan. We also discuss the reported discrepancy in the context of the extended first law of black hole thermodynamics by allowing the pressure term.

Yongwan Gim; Wontae Kim; Sang-Heon Yi

2014-03-19T23:59:59.000Z

335

Core Holes At Valles Caldera - Redondo Geothermal Area (Goff...

understand the stratigraphy, structure, hydrothermal alteration, and subsurface architecture of the Valles caldera. Several authors have reported results from these core holes,...

336

Core Holes At Valles Caldera - Sulphur Springs Geothermal Area...

337

Thermal Gradient Holes At Glass Mountain Area (Cumming And Mackie...

Area (Cumming And Mackie, 2007) Exploration Activity Details Location Glass Mountain Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not...

338

Location Of Hole And Electron Traps On Nanocrystalline Anatase...

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to two overlapping distributions: hole trap emission associated with oxygen vacancies on (101) exposed surfaces, which peaks in the green, and a broader emission...

339

Thermal Gradient Holes At Breitenbush Hot Springs Area (Ingebritsen...

(1993) Heat Flow From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Additional References Retrieved from "http:en.openei.orgwindex.php?titleThermalGr...

340

Extremal charged rotating dilaton black holes in odd dimensions

Employing higher-order perturbation theory, we find a new class of charged rotating black hole solutions of Einstein-Maxwell-dilaton theory with general dilaton coupling constant. Starting from the Myers-Perry solutions, we use the electric charge as the perturbative parameter, and focus on extremal black holes with equal-magnitude angular momenta in odd dimensions. We perform the perturbations up to 4th order for black holes in 5 dimensions and up to 3rd order in higher odd dimensions. We calculate the physical properties of these black holes and study their dependence on the charge and the dilaton coupling constant.

Allahverdizadeh, Masoud; Kunz, Jutta; Navarro-Lerida, Francisco [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503 D-26111 Oldenburg (Germany); Departamento de Fisica Atomica, Molecular y Nuclear, Ciencias Fisicas Universidad Complutense de Madrid, E-28040 Madrid (Spain)

2010-09-15T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

341

Extremal Charged Rotating Dilaton Black Holes in Odd Dimensions

Employing higher order perturbation theory, we find a new class of charged rotating black hole solutions of Einstein-Maxwell-dilaton theory with general dilaton coupling constant. Starting from the Myers-Perry solutions, we use the electric charge as the perturbative parameter, and focus on extremal black holes with equal-magnitude angular momenta in odd dimensions. We perform the perturbations up to 4th order for black holes in 5 dimensions and up to 3rd order in higher odd dimensions. We calculate the physical properties of these black holes and study their dependence on the charge and the dilaton coupling constant.

Masoud Allahverdizadeh; Jutta Kunz; Francisco Navarro-Lerida

2010-07-24T23:59:59.000Z

342

Probabilistic Field Coverage using a Hybrid Network of Static and Mobile Sensors

Probabilistic Field Coverage using a Hybrid Network of Static and Mobile Sensors Dan Wang, sensor network applications. For a field with unevenly distributed an area will be uncovered by any sensor, leaving a hole in static sensors, a quality coverage with acceptable network lifetime the field

Liu, Jiangchuan (JC)

343

p-wave Holographic Superconductors from Born-Infeld Black Holes

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...

Chaturvedi, Pankaj

2015-01-01T23:59:59.000Z

344

ACCRETION-JET CONNECTION IN BLACK HOLES THE ORIGIN OF STELLAR BLACK HOLES &

a very large kinetic energy...Moon @ >.9c" #12;POWERFUL DARK JETS FROM BLACK HOLES Radio (Dubner et al erg/sec Â· NON RADIATIVE JETS = "DARK" JETS Â· >50% OF THE ENERGY IS NOT RADIATED 1o = 60 pc1arcsec VLA Since their discovery there have been seven International workshops Compact binaries with jets #12

Maryland at College Park, University of

345

Geodesic Study of Regular Hayward Black Hole

This paper is devoted to study the geodesic structure of regular Hayward black hole. The timelike and null geodesic have been studied explicitly for radial and non-radial motion. For timelike and null geodesic in radial motion there exists analytical solution, while for non-radial motion the effective potential has been plotted, which investigates the position and turning points of the particle. It has been found that massive particle moving along timelike geodesics path are dragged towards the BH and continues move around BH in particular orbits.

G. Abbas; U. Sabiullah

2014-06-03T23:59:59.000Z

346

CHARYBDIS: A Black hole event generator.

model of black hole production and decay which can be interfaced to existing Monte Carlo programs using the Les Houches accord [4]. The major new theoretical input to the generator is the inclusion of the recently calculated ‘grey-body’ factors for black... ? TH geometric arguments show that ?l,m? ? (?rh)2 in any number of dimensions, which means that at high energies the shape of the spectrum is like that of a black body. However the low energy behaviour of the grey-body factors is spin-dependent and also...

Harris, Chris M; Richardson, P; Webber, Bryan R

347

Conformal Invariance of Black Hole Temperature

It is shown that the surface gravity and temperature of a stationary black hole are invariant under conformal transformations of the metric that are the identity at infinity. More precisely, we find a conformal invariant definition of the surface gravity of a conformal Killing horizon that agrees with the usual definition(s) for a true Killing horizon and is proportional to the temperature as defined by Hawking radiation. This result is reconciled with the intimate relation between the trace anomaly and the Hawking effect, despite the {\\it non}invariance of the trace anomaly under conformal transformations.

Ted Jacobson; Gungwon Kang

1993-07-06T23:59:59.000Z

348

Down-hole periodic seismic generator

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.

Hardee, H.C.; Hills, R.G.; Striker, R.P.

1982-10-28T23:59:59.000Z

349

Black Hole Constraints on Varying Fundamental Constants

We apply the generalized second law of thermodynamics and derive upper limits on the variation in the fundamental constants. The maximum variation in the electronic charge permitted for black holes accreting and emitting in the present cosmic microwave background corresponds to a variation in the fine-structure constant of {delta}{alpha}/{alpha}{approx_equal}2x10{sup -23} per second. This value matches the variation measured by Webb et al. [Phys. Rev. Lett. 82, 884 (1999); Phys. Rev. Lett. 87, 091301 (2001)] using absorption lines in the spectra of distant quasars and suggests the variation mechanism may be a coupling between the electron and the cosmic photon background.

MacGibbon, Jane H. [Department of Physics and Chemistry, University of North Florida, Jacksonville, Florida 32224 (United States)

2007-08-10T23:59:59.000Z

350

The Fourth Law of Black Hole Thermodynamics

We show that black holes fulfill the scaling laws arising in critical transitions. In particular, we find that in the transition from negative to positive values the heat capacities $C_{JQ}$, $C_{\\Omega Q}$ and $C_{J\\Phi}$ give rise to critical exponents satisfying the scaling laws. The three transitions have the same critical exponents as predicted by the universality Hypothesis. We also briefly discuss the implications of this result with regards to the connections among gravitation, quantum mechanics and statistical physics.

C. O. Lousto

1993-06-10T23:59:59.000Z

351

Black Hole Remnants at the LHC

We investigate possible signatures of black hole events at the LHC in the hypothesis that such objects will not evaporate completely, but leave a stable remnant. For the purpose of defining a reference scenario, we have employed the publicly available Monte Carlo generator CHARYBDIS2, in which the remnant's behavior is mostly determined by kinematic constraints and conservation of some quantum numbers, such as the baryon charge. Our findings show that electrically neutral remnants are highly favored and a significantly larger amount of missing transverse momentum is to be expected with respect to the case of complete decay.

L. Bellagamba; R. Casadio; R. Di Sipio; V. Viventi

2012-01-16T23:59:59.000Z

352

Primordial black holes as biased tracers

Primordial black holes (PBHs) are theoretical black holes which may be formed during the radiation dominant era and, basically, caused by the gravitational collapse of radiational overdensities. It has been well known that in the context of the structure formation in our Universe such collapsed objects, e.g., halos/galaxies, could be considered as bias tracers of underlying matter fluctuations and the halo/galaxy bias has been studied well. Employing a peak-background split picture which is known to be a useful tool to discuss the halo bias, we consider the large scale clustering behavior of the PBH and propose an almost mass-independent constraint to the scenario that dark matters (DMs) consist of PBHs. We consider the case where the statistics of the primordial curvature perturbations is almost Gaussian, but with small local-type non-Gaussianity. If PBHs account for the DM abundance, such a large scale clustering of PBHs behaves as nothing but the matter isocurvature perturbation and constrained strictly by...

Tada, Yuichiro

2015-01-01T23:59:59.000Z

353

Electrical Generating Capacities of Geothermal Slim Holes

Theoretical calculations are presented to estimate the electrical generating capacity of the hot fluids discharged from individual geothermal wells using small wellhead generating equipment over a wide range of reservoir and operating conditions. The purpose is to appraise the possibility of employing slim holes (instead of conventional production-size wells) to power such generators for remote off-grid applications such as rural electrification in developing countries. Frequently, the generating capacity desired is less than one megawatt, and can be as low as 100 kilowatts; if slim holes can be usefully employed, overall project costs will be significantly reduced. This report presents the final results of the study. Both self-discharging wells and wells equipped with downhole pumps (either of the ''lineshaft'' or the ''submersible'' type) are examined. Several power plant designs are considered, including conventional single-flash backpressure and condensing steam turbines, binary plants, double-flash steam plants, and steam turbine/binary hybrid designs. Well inside diameters from 75 mm to 300 mm are considered; well depths vary from 300 to 1200 meters. Reservoir temperatures from 100 C to 240 C are examined, as are a variety of reservoir pressures and CO2 contents and well productivity index values.

Pritchett, J.W.

1998-10-01T23:59:59.000Z

354

We study thermodynamic quantities of an acoustic black hole and its thermodynamic stability in a cavity based on the generalized uncertainty principle. It can be shown that there is a minimal black hole which can be a stable remnant after black hole evaporation. Moreover, the behavior of the free energy shows that the large black hole is stable too. Therefore, the acoustic black hole can decay into the remnant or the large black hole.

Wontae Kim; Edwin J. Son; Myungseok Yoon

2008-01-09T23:59:59.000Z

355

Intermediate-Mass Black Holes as LISA Sources

Intermediate-mass black holes (IMBHs), with masses of hundreds to thousands of solar masses, will be unique sources of gravitational waves for LISA. Here we discuss their context as well as specific characteristics of IMBH-IMBH and IMBH-supermassive black hole mergers and how these would allow sensitive tests of the predictions of general relativity in strong gravity.

M. Coleman Miller

2008-12-16T23:59:59.000Z

356

Binary Black Hole Accretion Flows in Merged Galactic Nuclei

Science Journals Connector (OSTI)

......for Theoretical Physics, Oiwake-cho...when the gas can pass across the maximum...mass-capture rates are eventually...holes|black hole physics|galaxies: nuclei...when the gas can pass across the maximum...mass-capture rates exhibit little...for Theoretical Physics (YITP) of Kyoto......

Kimitake Hayasaki; Shin Mineshige; Hiroshi Sudou

2007-04-25T23:59:59.000Z

357

Quasar evolution and the growth of black holes

Science Journals Connector (OSTI)

......hole which accretes at a rate that is ultimately limited...intermittently at an average rate that is a universal function...that the mean accretion rate scales as M 1.5 t 6...sufficiently massive galaxies pass through a quasar phase...accretion discs|black hole physics|galaxies: active......

Todd A. Small; Roger D. Blandford

1992-12-15T23:59:59.000Z

358

Accelerating and rotating black holes J. B. Griffiths1

Accelerating and rotating black holes J. B. Griffiths1 and J. PodolskÂ´y2 1Department Abstract An exact solution of Einstein's equations which represents a pair of accelerating and rotating which explicitly contains the known special cases for either rotating or accelerating black holes

359

Evaluating an icon of population persistence: the Devil's Hole pupfish

Science Journals Connector (OSTI)

...research-article Research articles 1001 60 197 Evaluating an icon of population persistence: the Devil's Hole pupfish J. Michael...Based on our analyses, we conclude that rather than being an icon of unusual persistence in isolation, the Devil's Hole pupfish...

2014-01-01T23:59:59.000Z

360

Synchronous Black Hole Search in Directed Graphs Adrian Kosowski

Synchronous Black Hole Search in Directed Graphs Adrian Kosowski Alfredo Navarra Cristina M called black hole nodes, and once a robot enters in one of them, it is destroyed. The goal is to find supported by the Italian CNR Short-Term Mobility Program. A. Kosowski was supported Polish Ministry Grant N

Paris-Sud XI, UniversitÃ© de

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

361

Modified Black Hole with Polar Jet and Vortex

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.

T. Tmmalm

2001-12-06T23:59:59.000Z

362

Electromagnetic extraction of energy from Kerr black holes

We elucidate the `right' process for energy extraction from Kerr black holes through `FFDE' magnetospheres, free from causality violation. It is shown that the magnetosphere of a Kerr black hole possesses the double-structure, consisting of the inner and outer magnetospheres with the pair-creation gap between them and with respective unipolar batteries at the inner and outer surfaces of the gap.

Isao Okamoto

2005-06-14T23:59:59.000Z

363

Black holes at the IceCube neutrino telescope

Science Journals Connector (OSTI)

If the fundamental Planck scale is about a TeV and the cosmic neutrino flux is at the Waxman-Bahcall level, quantum black holes are created daily in the Antarctic ice cap. We reexamine the prospects for observing such black holes with the IceCube neutrino-detection experiment. To this end, we first revise the black hole production rate by incorporating the effects of inelasticty, i.e., the energy radiated in gravitational waves by the multipole moments of the incoming shock waves. After that we study in detail the process of Hawking evaporation accounting for the black hole’s large momentum in the lab system. We derive the energy spectrum of the Planckian cloud which is swept forward with a large, O(106), Lorentz factor. (It is noteworthy that the boosted thermal spectrum is also relevant for the study of near-extremal supersymmetric black holes, which could be copiously produced at the Large Hadron Collider.) In the semiclassical regime, we estimate the average energy of the boosted particles to be less than 20% the energy of the ? progenitor. Armed with such a constraint, we determine the discovery reach of IceCube by tagging on soft (relative to what one would expect from charged current standard model processes) muons escaping the electromagnetic shower bubble produced by the black hole’s light descendants. The statistically significant 5? excess extends up to a quantum gravity scale ?1.3??TeV.

Luis A. Anchordoqui; Matthew M. Glenz; Leonard Parker

2007-01-09T23:59:59.000Z

364

Instabilities of (near) extremal rotating black holes in higher dimensions

Recently, Durkee and Reall have conjectured a criterion for linear instability of rotating, extremal, asymptotically Minkowskian black holes in $d\\ge 4$ dimensions, such as the Myers-Perry black holes. They considered a certain elliptic operator, $\\cal A$, acting on symmetric traceless tensors intrinsic to the horizon. Based in part on numerical evidence, they suggested that if the lowest eigenvalue, $\\lambda$, of this operator is less than the critical value $-1/4$ ( called "effective BF-bound"), then the black hole is linearly unstable. In this paper, we prove their conjecture. Our proof uses a combination of methods such as (i) the "canonical energy method" of Hollands-Wald, (ii) algebraically special properties of the near horizon geometries associated with the black hole, and (iii) the structure of the (linearized) constraint equations. Our method of proof is also applicable to rotating, extremal asymptotically Anti-deSitter black holes. In that case, our methods show that "all" such black holes are unstable. Although we explicitly discuss in this paper only extremal black holes, we argue that our methods can be generalized straightforwardly to obtain the same results for "near" extremal black holes.

Stefan Hollands; Akihiro Ishibashi

2014-08-04T23:59:59.000Z

365

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.

Paul M. Alsing

2015-02-04T23:59:59.000Z

366

Graviton Emission in the Bulk by a Simply Rotating Black Hole

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.

P. Kanti; Hideo Kodama; R. A. Konoplya; N. Pappas; A. Zhidenko

2010-06-07T23:59:59.000Z

367

Low frequency radiation from a (compact) structure with and without sound holes.

Science Journals Connector (OSTI)

At long wavelengths a force driven closed elastic structure radiates as a dipole. However this may or may not be the case in the presence of a sound hole. Radiation remains dipole?like when the interior volume behaves as an acoustic fluid coupled to the structure. This is commonly referred to as the sound hole sum rule in musical acoustics [Weinreich (1985)]. However should the interior acoustic volume be uncoupled or simply ignored the radiated field is dominated by a monopole contribution. For example this may occur with mechanically isolated piping systems exposed to the exterior medium. In this situation the monopole or dipole nature of the radiation depends on the effective number of sound holes for example whether the driven system is well connected to the exterior along both the inlet and outlet. Finite element structural?acoustic models are developed and exercised to investigate these systems and issues. In addition a substructuring technique is utilized to account for the potential influences of interior structural complexity.

2009-01-01T23:59:59.000Z

368

Polarimetric Imaging of the Massive Black Hole at the Galactic Center

The radio source Sgr A* in the Galactic center emits a polarized spectrum at millimeter and sub-millimeter wavelengths that is strongly suggestive of relativistic disk accretion onto a massive black hole. We use the well-constrained mass of Sgr A* and a magnetohydrodynamic model of the accretion flow to match both the total flux and polarization from this object. Our results demonstrate explicitly that the shift in the position angle of the polarization vector, seen at wavelengths near the peak of the mm to sub-mm emission from this source, is a signal of relativistic accretion flow in a strong gravitational field. We provide maps of the polarized emission to illustrate how the images of polarized intensity from the vicinity of the black hole would appear in upcoming observations with very long baseline radio interferometers (VLBI). Our results suggest that near-term VLBI observations will be able to directly image the polarized Keplerian portion of the flow near the horizon of the black hole.

Benjamin C. Bromley; Fulvio Melia; Siming Liu

2001-06-11T23:59:59.000Z

369

Research on extracting science from binary-black-hole (BBH) simulations has often adopted a 'scattering matrix' perspective: given the binary's initial parameters, what are the final hole's parameters and the emitted gravitational waveform? In contrast, we are using BBH simulations to explore the nonlinear dynamics of curved spacetime. Focusing on the head-on plunge, merger, and ringdown of a BBH with transverse, antiparallel spins, we explore numerically the momentum flow between the holes and the surrounding spacetime. We use the Landau-Lifshitz field-theory-in-flat-spacetime formulation of general relativity to define and compute the density of field energy and field momentum outside horizons and the energy and momentum contained within horizons, and we define the effective velocity of each apparent and event horizon as the ratio of its enclosed momentum to its enclosed mass-energy. We find surprisingly good agreement between the horizons' effective and coordinate velocities. During the plunge, the holes experience a frame-dragging-induced acceleration orthogonal to the plane of their spins and their infall ('downward'), and they reach downward speeds of order 1000 km/s. When the common apparent horizon forms (and when the event horizons merge and their merged neck expands), the horizon swallows upward field momentum that resided between the holes, causing the merged hole to accelerate in the opposite ('upward') direction. As the merged hole and the field energy and momentum settle down, a pulsational burst of gravitational waves is emitted, and the merged hole has a final effective velocity of about 20 km/s upward, which agrees with the recoil velocity obtained by measuring the linear momentum carried to infinity by the emitted gravitational radiation. To investigate the gauge dependence of our results, we compare generalized harmonic and Baumgarte-Shapiro-Shibata-Nakamura-moving-puncture evolutions of physically similar initial data; although the generalized harmonic and Baumgarte-Shapiro-Shibata-Nakamura-moving-puncture simulations use different gauge conditions, we find remarkably good agreement for our results in these two cases. We also compare our simulations with the post-Newtonian trajectories and near-field energy-momentum.

Lovelace, Geoffrey [Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, 14853 (United States); Chen Yanbei; Cohen, Michael; Kaplan, Jeffrey D.; Keppel, Drew; Matthews, Keith D.; Nichols, David A.; Scheel, Mark A.; Sperhake, Ulrich [Theoretical Astrophysics 350-17, California Institute of Technology, Pasadena, California 91125 (United States)

2010-09-15T23:59:59.000Z

370

E-Print Network 3.0 - access hole parameters Sample Search Results

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

features in this regime whenever the quantum dot hole level is resonant with two... -dimensional hole states located at the capping layer-blocking barrier interface in our...

371

Slim Holes At Fort Bliss Area (DOE GTP) | Open Energy Information

Fort Bliss Area Exploration Technique Slim Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes 2 slim holes References (1 January 2011) GTP ARRA Spreadsheet...

372

Fuel injector Holes (Fabrication of Micro-Orifices for Fuel Injectors...

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

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...

373

Thermal Gradient Holes At Coso Geothermal Area (1976) | Open Energy

Thermal Gradient Holes At Coso Geothermal Area (1976) Thermal Gradient Holes At Coso Geothermal Area (1976) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Coso Geothermal Area (1976) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 1976 Usefulness useful DOE-funding Unknown Notes Temperatures have been obtained to depths up to 133 m in 22 boreholes with measurements being made at least four times in each borehole. Geothermal gradients ranged from 240C/km to 450 0C/km. References Combs, J. (1 December 1976) Heat flow determinations and implied thermal regime of the Coso geothermal area, California Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Coso_Geothermal_Area_(1976)&oldid=511217"

374

Hypervelocity binary stars: smoking gun of massive binary black holes

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.

Youjun Lu; Qingjuan Yu; D. N. C. Lin

2007-07-12T23:59:59.000Z

375

Experimental Signature for Black Hole Production in Neutrino Air Showers

The existence of extra degrees of freedom beyond the electroweak scale may allow the formation of black holes in nearly horizontal neutrino air showers. In this paper we examine the average properties of the light descendants of these black holes. Our analysis indicates that black hole decay gives rise to deeply penetrating showers with an electromagnetic component which differs substantially from that in conventional neutrino interactions, allowing a good characterization of the phenomenon against background. Naturally occurring black holes in horizontal neutrino showers could be detected and studied with the Auger air shower array. Since the expected black hole production rate at Auger is $> 1$ event/year, this cosmic ray observatory could be potentially powerful in probing models with extra dimensions and TeV-scale gravity.

Luis Anchordoqui; Haim Goldberg

2001-10-15T23:59:59.000Z

376

Extremal black holes and the first law of thermodynamics

Science Journals Connector (OSTI)

We study the low-temperature expansion of the first law of thermodynamics for near-extremal black holes. We show that for extremal black holes with nonvanishing entropy, the leading-order contribution yields an expression for their extremal entropy that is in agreement with the entropy-function result. When their entropy vanishes due to the vanishing of a one-cycle on the horizon, such a leading contribution is always compatible with the first law satisfied by a Bañados-Teitelboim-Zanelli black hole. The universality of these results follows from universal facts about extremal black holes. Our results are consistent with both the presence of local AdS2 and AdS3 near-horizon throats for extremal black holes and with the suggested quantum microscopic descriptions (AdS2/CFT1, Kerr/CFT, and extremal vanishing horizon/CFT).

Maria Johnstone; M. M. Sheikh-Jabbari; Joan Simón; Hossein Yavartanoo

2013-11-27T23:59:59.000Z

377

Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett,

Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

378

Greybody factors in a rotating black-hole background: Fermions and gauge bosons

Science Journals Connector (OSTI)

We study the emission of fermion and gauge boson degrees of freedom on the brane by a rotating higher-dimensional black hole. Using matching techniques, for the near-horizon and far-field regime solutions, we solve analytically the corresponding field equations of motion. From this, we derive analytical results for the absorption probabilities and Hawking radiation emission rates, in the low-energy and low-rotation case, for both species of fields. We produce plots of these, comparing them to existing exact numerical results with very good agreement. We also study the total absorption cross section and demonstrate that, as in the nonrotating case, it has a different behavior for fermions and gauge bosons in the low-energy limit, while it follows a universal behavior—reaching a constant, spin-independent, asymptotic value—in the high-energy regime.

S. Creek, O. Efthimiou, P. Kanti, and K. Tamvakis

2007-11-09T23:59:59.000Z

379

What is a chiral 2d CFT? And what does it have to do with extremal black holes?

The near horizon limit of the extremal BTZ black hole is a``self-dual orbifold'' of AdS_3. This geometry has a null circle on its boundary, and thus the dual field theory is a Discrete Light Cone Quantized (DLCQ) two dimensional CFT. The same geometry can be compactified to two dimensions giving AdS_2 with a constant electric field. The kinematics of the DLCQ show that in a consistent quantum theory of gravity in these backgrounds there can be no dynamics in AdS_2, which is consistent with older ideas about instabilities in this space. We show how the necessary boundary conditions eliminating AdS_2 fluctuations can be implemented, leaving one copy of a Virasoro algebra as the asymptotic symmetry group. Our considerations clarify some aspects of the chiral CFTs appearing in proposed dual descriptions of the near-horizon degrees of freedom of extremal black holes.

Vijay Balasubramanian; Jan de Boer; M. M. Sheikh-Jabbari; Joan Simon

2009-06-17T23:59:59.000Z

380

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.

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)

2014-01-27T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

381

Resonant third-harmonic generation of a short-pulse laser from electron-hole plasmas

In semiconductors, free carriers are created in pairs in inter-band transitions and consist of an electron and its corresponding hole. At very high carrier densities, carrier-carrier collisions dominate over carrier-lattice collisions and carriers begin to behave collectively to form plasma. Here, we apply a short-pulse laser to generate third-harmonic radiation from a semiconductor plasma (electron-hole plasma) in the presence of a transverse wiggler magnetic-field. The process of third-harmonic generation of an intense short-pulse laser is resonantly enhanced by the magnetic wiggler, i.e., wiggler magnetic field provides the necessary momentum to third-harmonic photons. In addition, a high-power laser radiation, propagating through a semiconductor imparts an oscillatory velocity to the electrons and exerts a ponderomotive force on electrons at the third-harmonic frequency of the laser. This oscillatory velocity produces a third-harmonic longitudinal current. And due to the beating of the longitudinal electron velocity and the wiggler magnetic field, a transverse third-harmonic current is produced that drives third-harmonic electromagnetic radiation. It is finally observed that for a specific wiggler wave number value, the phase-matching conditions for the process are satisfied, leading to resonant enhancement in the energy conversion efficiency.

Kant, Niti [Department of Physics, Lovely Professional University, Phagwara, Punjab 144 402 (India); Nandan Gupta, Devki [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Suk, Hyyong [Advanced Photonics Research Institute (APRI) and Graduate Program of Photonics and Applied Physics, Gwangju Institute of Science and Technology, Gwangju 500 712 (Korea, Republic of)

2012-01-15T23:59:59.000Z

382

Photocurrent in bulk heterojunction solar cells with similar electron and hole mean free path

We present photocurrents at several temperatures carried out in a bulk heterojunction photovoltaic device. To explain the results, we developed an analytical model assuming non-injecting contacts and equal mean free paths for electrons and holes. The fitting of the equation to the experimental data provided the temperature evolution of the charge transfer state dissociation probability (P) and ??, where ? is the charge carrier mobility and ? is the charge carrier lifetime. The photocurrent expression tends towards a saturation value of eGPL for high electric fields, where GP is the generation rate of charge carriers.

Coutinho, Douglas José; Faria, Roberto Mendonça, E-mail: faria@ifsc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, C.P. 369, 13560-970 São Carlos, SP (Brazil)

2013-11-25T23:59:59.000Z

383

What's Wrong With Black Hole Thermodynamics?

Not only is the Bekenstein expression for the entropy of a black hole a convex function of the energy, rather than being a concave function as it must be, it predicts a final equilibrium temperature given by the harmonic mean. This violates the third law, and the principle of maximum work. The property that means are monotonically increasing functions of their argument underscores the error of transferring from temperature means to means in the internal energy when the energy is not a monotonically increasing function of temperature. Whereas the former leads to an increase in entropy, the latter lead to a decrease in entropy thereby violating the second law. The internal energy cannot increase at a slower rate than the temperature itself.

B. H. Lavenda

2011-10-23T23:59:59.000Z

384

The Galactic Center Black Hole Laboratory

The super-massive 4 million solar mass black hole Sagittarius~A* (SgrA*) shows flare emission from the millimeter to the X-ray domain. A detailed analysis of the infrared light curves allows us to address the accretion phenomenon in a statistical way. The analysis shows that the near-infrared flare amplitudes are dominated by a single state power law, with the low states in SgrA* limited by confusion through the unresolved stellar background. There are several dusty objects in the immediate vicinity of SgrA*. The source G2/DSO is one of them. Its nature is unclear. It may be comparable to similar stellar dusty sources in the region or may consist predominantly of gas and dust. In this case a particularly enhanced accretion activity onto SgrA* may be expected in the near future. Here the interpretation of recent data and ongoing observations are discussed.

Eckart, A; Valencia-S., M; Straubmeier, C; Zensus, J A; Karas, V; Kunneriath, D; Alberdi, A; Sabha, N; Schödel, R; Puetzfeld, D

2015-01-01T23:59:59.000Z

385

Complementary junction heterostructure field-effect transistor

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.

Baca, A.G.; Drummond, T.J.; Robertson, P.J.; Zipperian, T.E.

1995-12-26T23:59:59.000Z

386

Relativistic hydrodynamics in the presence of puncture black holes

Many of the recent numerical simulations of binary black holes in vacuum adopt the moving puncture approach. This successful approach avoids the need to impose numerical excision of the black hole interior and is easy to implement. Here we wish to explore how well the same approach can be applied to moving black hole punctures in the presence of relativistic hydrodynamic matter. First, we evolve single black hole punctures in vacuum to calibrate our Baumgarte-Shapiro-Shibata-Nakamura implementation and to confirm that the numerical solution for the exterior spacetime is invariant to any junk (i.e., constraint-violating) initial data employed in the black hole interior. Then we focus on relativistic Bondi accretion onto a moving puncture Schwarzschild black hole as a numerical test bed for our high-resolution shock-capturing relativistic hydrodynamics scheme. We find that the hydrodynamical equations can be evolved successfully in the interior without imposing numerical excision. These results help motivate the adoption of the moving puncture approach to treat the binary black hole-neutron star problem using conformal thin-sandwich initial data.

Faber, Joshua A.; Etienne, Zachariah B.; Shapiro, Stuart L.; Taniguchi, Keisuke [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Baumgarte, Thomas W. [Department of Physics and Astronomy, Bowdoin College, Brunswick, Maine 04011 (United States)

2007-11-15T23:59:59.000Z

387

Nonphotochemical hole burning and dispersive kinetics in amorphous solids

Results covering burn intensities in the nW to {mu}W/cm{sup 2} range, of dispersive hole growth kinetics are reported for Oxazine 720 in glycerol glasses and polyvinyl alcohol polymer films and their deuterated analogues. A theoretical model which employs a distribution function for the hole burning rate constant based upon a Gaussian distribution for the tunnel parameter is shown to accurately describe the kinetic data. This model incorporates the linear electron-phonon coupling. A method for calculating the nonphotochemical quantum yield is presented which utilizes the Gaussian distribution of tunnel parameters. The quantum yield calculation can be extended to determine a quantum yield as a function of hole depth. The effect of spontaneous hole filling is shown to be insignificant over the burn intensity range studied. Average relaxation rates for hole burning are {approximately}8 orders of magnitude greater than for hole filling. The dispersive kinetics of hole burning are observed to be independent over the temperature range of these experiments, 1.6 to 7.0 K. 6 refs., 20 figs., 1 tab.

Kenney, M.J.

1990-09-21T23:59:59.000Z

388

Black Holes and the Third Law of Thermodynamics

We discuss in the framework of black hole thermodynamics some aspects relative to the third law in the case of black holes of the Kerr-Newman family. In the light of the standard proof of the equivalence between the unattainability of the zero temperature and the entropic version of the third law it is remarked that the unattainability has a special character in black hole thermodynamics. Also the zero temperature limit which obtained in the case of very massive black holes is discussed and it is shown that a violation of the entropic version in the charged case occurs. The violation of the Bekenstein-Hawking law in favour of zero entropy S_E=0 in the case of extremal black holes is suggested as a natural solution for a possible violation of the second law of thermodynamics. Thermostatic arguments in support of the unattainability are explored, and $S_E=0$ for extremal black holes is shown to be again a viable solution. The third law of black hole dynamics by W.Israel is then interpreted as a further strong corroboration to the picture of a discontinuity between extremal states and non-extremal ones.

F. Belgiorno; M. Martellini

2002-10-08T23:59:59.000Z

389

Dynamical evolution of quasi-circular binary black hole data

We study the fully nonlinear dynamical evolution of binary black hole data, whose orbital parameters are specified via the effective potential method for determining quasi-circular orbits. The cases studied range from the Cook-Baumgarte innermost stable circular orbit (ISCO) to significantly beyond that separation. In all cases we find the black holes to coalesce (as determined by the appearance of a common apparent horizon) in less than half an orbital period. The results of the numerical simulations indicate that the initial holes are not actually in quasi-circular orbits, but that they are in fact nearly plunging together. The dynamics of the final horizon are studied to determine physical parameters of the final black hole, such as its spin, mass, and oscillation frequency, revealing information about the inspiral process. We show that considerable resolution is required to extract accurate physical information from the final black hole formed in the merger process, and that the quasi-normal modes of the final hole are strongly excited in the merger process. For the ISCO case, by comparing physical measurements of the final black hole formed to the initial data, we estimate that less than 3% of the total energy is radiated in the merger process.

Miguel Alcubierre; Bernd Bruegmann; Peter Diener; F. Siddhartha Guzman; Ian Hawke; Scott Hawley; Frank Herrmann; Michael Koppitz; Denis Pollney; Edward Seidel; Jonathan Thornburg

2004-11-30T23:59:59.000Z

390

We present three-dimensional hydrodynamic simulations of the evolution of selfgravitating, thick accretion discs around hyperaccreting stellar-mass black holes. The black hole-torus systems are considered to be remnants of compact object mergers, in which case the disc is not fed by an external mass reservoir and the accretion is non-stationary. Our models take into account viscous dissipation, described by an alpha-law, a detailed equation of state for the disc gas, and an approximate treatment of general relativistic effects on the disc structure by using a pseudo-Newtonian potential for the black hole including its possible rotation and spin-up during accretion. Magnetic fields are ignored. The neutrino emission of the hot disc is treated by a neutrino-trapping scheme, and the neutrino-antineutrino annihilation near the disc is evaluated in a post-processing step. Our simulations show that the neutrino emission and energy deposition by neutrino-antineutrino annihilation increase sensitively with the disc mass, with the black hole spin in case of a disc in corotation, and in particular with the alpha-viscosity. We find that for sufficiently large alpha-viscosity neutrino-antineutrino annihilation can be a viable energy source for gamma-ray bursts.

S. Setiawan; M. Ruffert; H. -Th. Janka

2004-02-20T23:59:59.000Z

391

Accretion onto a black hole in a string cloud background

We examine the accretion process onto the black hole with a string cloud background, where the horizon of the black hole has an enlarged radius $r_H=2 M/(1-\\alpha)$, due to the string cloud parameter $\\alpha\\; (0 \\leq \\alpha cloud parameter $\\alpha$. We also find the gas compression ratios and temperature profiles below the accretion radius and at the event horizon. It is shown that the mass accretion rate, for both the relativistic and the non-relativistic fluid by a black hole in the string cloud model, increases with increase in $\\alpha$.

Apratim Ganguly; Sushant G. Ghosh; Sunil D. Maharaj

2014-09-28T23:59:59.000Z

392

Phenomenological Description of the Interior of the Schwarzschild Black Hole

We discuss a sufficiently large 4-dimensional Schwarzschild black hole which is in equilibrium with a heat bath. In other words, we consider a black hole which has grown up from a small one in the heat bath adiabatically. We express the metric of the interior of the black hole in terms of two functions: One is the intensity of the Hawking radiation, and the other is the ratio between the radiation energy and the pressure in the radial direction. Especially in the case of conformal matters we check that it is a self-consistent solution of the semi-classical Einstein equation, $G_{\\mu\

Hikaru Kawai; Yuki Yokokura

2014-09-19T23:59:59.000Z

393

Three-dimensional Chern-Simons black holes

We construct black hole solutions to three-dimensional Einstein-Maxwell theory with both gravitational and electromagnetic Chern-Simons terms. These intrinsically rotating solutions are geodesically complete, and causally regular within a certain parameter range. Their mass, angular momentum and entropy are found to satisfy the first law of black hole thermodynamics. These Chern-Simons black holes admit a four-parameter local isometry algebra, which generically is sl(2,R)xR, and may be generated from the corresponding vacua by local coordinate transformations.

Moussa, Karim Ait [Laboratoire de Physique Mathematique et Physique Subatomique, Departement de Physique, Faculte des Sciences, Universite Mentouri, Constantine 25000 (Algeria); Clement, Gerard; Leygnac, Cedric [Laboratoire de Physique Theorique LAPTH (CNRS), B.P.110, F-74941 Annecy-le-Vieux cedex (France); Guennoune, Hakim [Laboratoire de Physique Theorique LAPTH (CNRS), B.P.110, F-74941 Annecy-le-Vieux cedex (France); Departement de Physique, Faculte des Sciences, Universite Ferhat Abbas, Setif 19000 (Algeria)

2008-09-15T23:59:59.000Z

394

Black hole evaporation within a momentum-dependent metric

We investigate the black hole thermodynamics in a 'deformed' relativity framework where the energy-momentum dispersion law is Lorentz-violating and the Schwarzchild-like metric is momentum-dependent with a Planckian cutoff. We obtain net deviations of the basic thermodynamical quantities from the Hawking-Bekenstein predictions: actually, the black hole evaporation is expected to quit at a nonzero critical mass value (of the order of the Planck mass), leaving a zero temperature remnant, and avoiding a spacetime singularity. Quite surprisingly, the present semiclassical corrections to black hole temperature, entropy, and heat capacity turn out to be identical to the ones obtained within some quantum approaches.

Salesi, G.; Di Grezia, E. [Universita Statale di Bergamo, Facolta di Ingegneria, viale Marconi 5, I-24044 Dalmine (Italy) and Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, I-20133 Milan (Italy)

2009-05-15T23:59:59.000Z

395

Inferring black hole charge from backscattered electromagnetic radiation

We compute the scattering cross section of Reissner-Nordstr\\"om black holes for the case of an incident electromagnetic wave. We describe how scattering is affected by both the conversion of electromagnetic to gravitational radiation, and the parity-dependence of phase shifts induced by the black hole charge. The latter effect creates a helicity-reversed scattering amplitude that is non-zero in the backward direction. We show that from the character of the electromagnetic wave scattered in the backward direction it is possible, in principle, to infer if a static black hole is charged.

Luís C. B. Crispino; Sam R. Dolan; Atsushi Higuchi; Ednilton S. de Oliveira

2014-09-16T23:59:59.000Z

396

Hawking Radiation by Kerr Black Holes and Conformal Symmetry

The exponential blueshift associated with the event horizon of a black hole makes conformal symmetry play a fundamental role in accounting for its thermal properties. Using a derivation based on two-point functions, we show that the full spectrum of thermal radiation of scalar particles by Kerr black holes can be explicitly derived on the basis of a conformal symmetry arising in the wave equation near the horizon. The simplicity of our approach emphasizes the depth of the connection between conformal symmetry and black hole radiance.

Agullo, Ivan; Parker, Leonard [Physics Department, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States); Navarro-Salas, Jose [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC. Facultad de Fisica, Universidad de Valencia, Burjassot-46100, Valencia (Spain); Olmo, Gonzalo J. [Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain)

2010-11-19T23:59:59.000Z

397

Quantum Dot Light-Emitting Diode with Quantum Dots Inside the Hole Transporting Layers

architecture using a noninverted structure with the QDs sandwiched between hole transporting layers (HTLs

Demir, Hilmi Volkan

398

Scalar Field Quantum Inequalities in Static Spacetimes

We discuss quantum inequalities for minimally coupled scalar fields in static spacetimes. These are inequalities which place limits on the magnitude and duration of negative energy densities. We derive a general expression for the quantum inequality for a static observer in terms of a Euclidean two-point function. In a short sampling time limit, the quantum inequality can be written as the flat space form plus subdominant correction terms dependent upon the geometric properties of the spacetime. This supports the use of flat space quantum inequalities to constrain negative energy effects in curved spacetime. Using the exact Euclidean two-point function method, we develop the quantum inequalities for perfectly reflecting planar mirrors in flat spacetime. We then look at the quantum inequalities in static de~Sitter spacetime, Rindler spacetime and two- and four-dimensional black holes. In the case of a four-dimensional Schwarzschild black hole, explicit forms of the inequality are found for static observers nea...

Pfenning, M J; Pfenning, Michael J.

1998-01-01T23:59:59.000Z

399

THE LARGE-SCALE MAGNETIC FIELDS OF ADVECTION-DOMINATED ACCRETION FLOWS

We calculate the advection/diffusion of the large-scale magnetic field threading an advection-dominated accretion flow (ADAF) and find that the magnetic field can be dragged inward by the accretion flow efficiently if the magnetic Prandtl number P{sub m}={eta}/{nu}{approx}1. This is due to the large radial velocity of the ADAF. It is found that the magnetic pressure can be as high as {approx}50% of the gas pressure in the inner region of the ADAF close to the black hole horizon, even if the external imposed homogeneous vertical field strength is {approx}< 5% of the gas pressure at the outer radius of the ADAF, which is caused by the gas in the ADAF plunging rapidly to the black hole within the marginal stable circular orbit. In the inner region of the ADAF, the accretion flow is significantly pressured in the vertical direction by the magnetic fields, and therefore its gas pressure can be two orders of magnitude higher than that in the ADAF without magnetic fields. This means that the magnetic field strength near the black hole is underestimated by assuming equipartition between magnetic and gas pressure with the conventional ADAF model. Our results show that the magnetic field strength of the flow near the black hole horizon can be more than one order of magnitude higher than that in the ADAF at {approx}3R{sub g} (R{sub g} = 2GM/c{sup 2}), which implies that the Blandford-Znajek mechanism could be more important than the Blandford-Payne mechanism for ADAFs. We find that the accretion flow is decelerated near the black hole by the magnetic field when the external imposed field is strong enough or the gas pressure of the flow is low at the outer radius, or both. This corresponds to a critical accretion rate, below which the accretion flow will be arrested by the magnetic field near the black hole for a given external imposed field. In this case, the gas may accrete as magnetically confined blobs diffusing through field lines in the region very close to the black hole horizon, similar to those in compact stars. Our calculations are also valid for the case that the inner ADAF connects to the outer cold thin disk at a certain radius. In this case, the advection of the external fields is quite inefficient in the outer thin disk due to its low radial velocity, and the field lines thread the disk almost vertically, while these field lines can be efficiently dragged inward by the radial motion of the inner ADAF.

Cao Xinwu, E-mail: cxw@shao.ac.cn [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

2011-08-20T23:59:59.000Z

400

Probing Core-Hole Localization in Molecular Nitrogen

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Probing Core-Hole Localization in Molecular Nitrogen Print Probing Core-Hole Localization in Molecular Nitrogen Print The behavior of the core hole created in molecular x-ray photoemission experiments has provided molecular scientists with a valuable window through which to probe the electronic structure and dynamics of molecules. But the answer to one fundamental quantum question-whether the core hole is localized or delocalized-has remained elusive for diatomic molecules in which both atoms are the same element. An international team of scientists from the University of Frankfurt in Germany, Berkeley Lab, Kansas State University, and Auburn University has now resolved the issue with an appropriate twist of quantum fuzziness. By means of coincident detection of the photoelectron ejected from molecular nitrogen and the Auger electron emitted femtoseconds later, the team found that how the measurements are done determines which description-localized or delocalized-is valid.

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

401

Probing Core-Hole Localization in Molecular Nitrogen

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Probing Core-Hole Localization in Molecular Nitrogen Print Probing Core-Hole Localization in Molecular Nitrogen Print The behavior of the core hole created in molecular x-ray photoemission experiments has provided molecular scientists with a valuable window through which to probe the electronic structure and dynamics of molecules. But the answer to one fundamental quantum question-whether the core hole is localized or delocalized-has remained elusive for diatomic molecules in which both atoms are the same element. An international team of scientists from the University of Frankfurt in Germany, Berkeley Lab, Kansas State University, and Auburn University has now resolved the issue with an appropriate twist of quantum fuzziness. By means of coincident detection of the photoelectron ejected from molecular nitrogen and the Auger electron emitted femtoseconds later, the team found that how the measurements are done determines which description-localized or delocalized-is valid.

402

Geological and geophysical analysis of Coso Geothermal Exploration Hole No.

and geophysical analysis of Coso Geothermal Exploration Hole No. and geophysical analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Geological and geophysical analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Details Activities (5) Areas (1) Regions (0) Abstract: The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California, from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and extensive geophysical logging surveys were conducted to document the geologic character of the geothermal system as penetrated by CGEH-1. The major rock units encountered include a mafic metamorphic sequence and a

403

Core Holes At Long Valley Caldera Geothermal Area (Benoit, 1984...

Basis Several core holes were also drilled in the caldera's west moat by Phillips Petroleum Company in 1982, including: PLV-1, drilled to approximately 711 m depth PLV-2,...

404

Search for gravitational waves from intermediate mass binary black holes

We present the results of a weakly modeled burst search for gravitational waves from mergers of nonspinning intermediate mass black holes in the total mass range 100–450??M? and with the component mass ratios between 1?1 ...

Barsotti, Lisa

405

Primary caustics and critical points behind a Kerr black hole

The primary optical caustic surface behind a Kerr black hole is a four-cusped tube displaced from the line of sight. We derive the caustic surface in the nearly asymptotic region far from the black hole through a Taylor expansion of the lightlike geodesics up to and including fourth-order terms in m/b and a/b, where m is the black hole mass, a the spin, and b the impact parameter. The corresponding critical locus in the observer's sky is elliptical and a pointlike source inside the caustics will be imaged as an Einstein cross. With regard to lensing near critical points, a Kerr lens is analogous to a circular lens perturbed by a dipole and a quadrupole potential. The caustic structure of the supermassive black hole in the Galactic center could be probed by lensing of low mass x-ray binaries in the galactic inner regions or by hot spots in the accretion disk.

Sereno, Mauro; De Luca, Fabiana [Institut fuer Theoretische Physik, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)

2008-07-15T23:59:59.000Z

406

Analytical Kerr black hole lensing in the weak deflection limit

Science Journals Connector (OSTI)

We present an analytical treatment of gravitational lensing by a Kerr black hole in the weak deflection limit. Lightlike geodesics are expanded as a Taylor series up to and including third-order terms in m/b and a/b, where m is the black hole mass, a the angular momentum, and b the impact parameter of the light ray. Positions and magnifications of individual images are computed with a perturbative analysis. At this order, the degeneracy with the translated Schwarzschild lens is broken. The critical curve is still a circle displaced from the black hole position in the equatorial direction and the corresponding caustic is pointlike. The degeneracy between the black hole spin and its inclination relative to the observer is broken through the angular coordinates of the perturbed images.

Mauro Sereno and Fabiana De Luca

2006-12-21T23:59:59.000Z

407

Primary caustics and critical points behind a Kerr black hole

Science Journals Connector (OSTI)

The primary optical caustic surface behind a Kerr black hole is a four-cusped tube displaced from the line of sight. We derive the caustic surface in the nearly asymptotic region far from the black hole through a Taylor expansion of the lightlike geodesics up to and including fourth-order terms in m/b and a/b, where m is the black hole mass, a the spin, and b the impact parameter. The corresponding critical locus in the observer’s sky is elliptical and a pointlike source inside the caustics will be imaged as an Einstein cross. With regard to lensing near critical points, a Kerr lens is analogous to a circular lens perturbed by a dipole and a quadrupole potential. The caustic structure of the supermassive black hole in the Galactic center could be probed by lensing of low mass x-ray binaries in the galactic inner regions or by hot spots in the accretion disk.

Mauro Sereno and Fabiana De Luca

2008-07-09T23:59:59.000Z

408

On black hole evolution in active galactic nuclei

Science Journals Connector (OSTI)

......whether higher accretion rates during low activity periods...accretion discs|black hole physics|galaxies: active|galaxies...the decreasing accretion rate must pass through the range of intermediate accretion rates ( _10-3 .AEdd)' At......

R. Moderski; M. Sikora

1996-12-01T23:59:59.000Z

409

Neural network calibration for miniature multi-hole pressure probes

A robust and accurate neural network based algorithm phics. for the calibration of miniature multi-hole pressure probes has been developed and a detailed description of its features and use is presented. The code that was developed was intended...

Vijayagopal, Rajesh

1998-01-01T23:59:59.000Z

410

Quantum Emission from Two-Dimensional Black Holes

We investigate Hawking radiation from two-dimensional dilatonic black holes using standard quantization techniques. In the background of a collapsing black hole solution the Bogoliubov coefficients can be exactly determined. In the regime after the black hole has settled down to an `equilibrium' state but before the backreaction becomes important these give the known result of a thermal distribution of Hawking radiation at temperature lambda/(2pi). The density matrix is computed in this regime and shown to be purely thermal. Similar techniques can be used to derive the stress tensor. The resulting expression agrees with the derivation based on the conformal anomaly and can be used to incorporate the backreaction. Corrections to the thermal density matrix are also examined, and it is argued that to leading order in perturbation theory the effect of the backreaction is to modify the Bogoliubov transformation, but not in a way that restores information lost to the black holes.

Steven B. Giddings; W. M. Nelson

2009-11-27T23:59:59.000Z

411

The Energy for 2+1 Dimensional Black Hole Solutions

The energy distributions of four 2+1 dimensional black hole solutions were obtained by using the Einstein and M{\\o}ller energy-momentum complexes. while $r \\to \\infty$, the energy distributions of these four solutions become divergence.

I-Ching Yang; Irina Radinschi

2006-11-05T23:59:59.000Z

412

Nonphotochemical hole burning and dispersive kinetics in amorphous solids.

??Results of an extensive study, covering burn intensities in the nW to {dollar}?{dollar}W/cm{dollar}2{dollar} range, of dispersive hole growth kinetics are reported for Oxazine 720 in… (more)

Kenney, Michael Joseph

1990-01-01T23:59:59.000Z

413

Lovelock black holes in a string cloud background

We present an exact static, spherically symmetric black hole solution to the third order Lovelock gravity with a string cloud background in seven dimensions for the special case when the second and third order Lovelock coefficients are related via $\\tilde{\\alpha}^2_2=3\\tilde{\\alpha}_3\\;(\\equiv\\alpha^2)$. Further, we examine thermodynamic properties of this black hole to obtain exact expressions for mass, temperature, entropy and also perform the thermodynamic stability analysis. We see that a string cloud background makes a profound influence on horizon structure, thermodynamic properties and the stability of black holes. Interestingly, the entropy of the black hole is unaffected due to a string cloud background. However, the critical solution for thermodynamic stability is being affected by a string cloud background.

Tae-Hun Lee; Dharmanand Baboolal; Sushant G. Ghosh

2014-09-12T23:59:59.000Z

414

General solutions for thermopiezoelectrics with various holes under thermal loading

induced by thermal loads. The loads may be uniform remote heat Â¯ow, point heat source and temperature elastic plate with an hole of various shapes subjected to remote uniform mechanical loading. For plane

Qin, Qinghua

415

Thermodynamics and Thermodynamic geometry of Park black hole

We study the thermodynamics and thermodynamic geometry of Park black hole in Ho\\v{r}ava gravity. By incorporating the ideas of differential geometry, we have investigated the thermodynamics using Weinhold geometry and Ruppeiner geometry. We have also analyzed it in the context of newly developed geometrothermodynamics(GTD). Divergence of specific heat is associated with the second order phase transition of black hole. Here in the context of Park black hole, both Weinhold's metric and Ruppeiner's metric well explain this phase transition. But these explanations depend on the choice of potential. Hence the Legendre invariant GTD is used, and with the true singularities in the curvature scalar, GTD well explain the second order phase transition. All these methods together give an exact idea of all the behaviors of the Park black hole thermodynamics.

Jishnu Suresh; Tharanath R; Nijo Varghese; V C Kuriakose

2014-03-19T23:59:59.000Z

416

Core Holes At Valles Caldera - Sulphur Springs Geothermal Area...

Dennis L. Nielson, Pisto Larry, C.W. Criswell, R. Gribble, K. Meeker, J.A. Musgrave, T. Smith, D. Wilson (1989) Scientific Core Hole Valles Caldera No. 2B (VC-2B), New Mexico:...

417

Temperatures, heat flow, and water chemistry from drill holes...

Temperatures, heat flow, and water chemistry from drill holes in the Raft River geothermal system, Cassia County, Idaho Jump to: navigation, search OpenEI Reference LibraryAdd to...

418

T-693: Symantec Endpoint Protection Manager Input Validation Hole Permits

Broader source: Energy.gov (indexed) [DOE]

3: Symantec Endpoint Protection Manager Input Validation Hole 3: Symantec Endpoint Protection Manager Input Validation Hole Permits Cross-Site Scripting and Cross-Site Request Forgery Attacks T-693: Symantec Endpoint Protection Manager Input Validation Hole Permits Cross-Site Scripting and Cross-Site Request Forgery Attacks August 15, 2011 - 3:42pm Addthis PROBLEM: Two vulnerabilities were reported in Symantec Endpoint Protection Manager. A remote user can conduct cross-site scripting attacks. A remote user can conduct cross-site request forgery attacks. PLATFORM: Version(s): 11.0 RU6(11.0.600x), 11.0 RU6-MP1(11.0.6100), 11.0 RU6-MP2(11.0.6200), 11.0 RU6-MP3(11.0.6300) ABSTRACT: Symantec Endpoint Protection Manager Input Validation Hole Permits Cross-Site Scripting and Cross-Site Request Forgery Attacks. reference LINKS:

419

Particle acceleration by Majumdar-Papapetrou di-hole

We explore the multi-black hole spacetimes from the perspective of the ultra-high energy particle collisions. Such a discussion is limited to the spacetimes containing a single black hole so far. We deal with the Majumdar-Papapetrou solution representing a system consisting of two identical black holes in the equilibrium. In order to identify the conditions suitable for the process of high energy collisions, we consider particles confined to move on the equatorial plane towards the axis of symmetry with the zero angular momentum. We consider collision between the particles moving in opposite directions at the location midway between the black holes on the axis. We show that the center of mass energy of collision between the particles increases with the decrease in the separation between the black holes and shows divergence in the limit where the separation goes to zero. We estimate the size of the region close to the central point on the equatorial plane where it would be possible to have high energy collisions and show that this region has a reasonably large spatial extent. We further explore the process of high energy collisions with the general geodesics with arbitrary angular momentum on the equatorial plane away from the central point. Although in this paper we deal with theMajumdar-Papapetrou spacetime which serves as a toy example representing multiple black holes, we speculate on the possibility that the ultra-high energy collisions would also occur in the more general setting like colliding black holes, when distance between the black holes is extremely small, which can in principle be verified in the numerical relativity simulations.

Mandar Patil; Pankaj S. Joshi

2014-09-03T23:59:59.000Z

420

Remarks about Static Back-Reaction on Black Hole Spacetimes

Recently, it has been claimed that the back reaction of vacuum polarization on a black hole spacetime naturally regularizes infinities in the black hole entropy. We examine the back reaction calculation and find no such short-distance cut-off,in contradiction with these recent claims. Moreover, the intuitive expectation that the perturbative calculation breaks down near the event horizon is confirmed. The new surface gravity diverges and the metric is degenerate at the stretched horizon.

Neil J. Cornish; Janna J. Levin

1994-11-13T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

421

Overspinning a Black Hole with a Test Body

Science Journals Connector (OSTI)

It has long been known that a maximally spinning black hole cannot be overspun by tossing in a test body. Here we show that if instead the black hole starts out with below maximal spin, then indeed overspinning can be achieved. We find that requirements on the size and internal structure of the test body can be met if the body carries in orbital but not spin angular momentum. Our analysis neglects radiative and self-force effects, which may prevent the overspinning.

Ted Jacobson and Thomas P. Sotiriou

2009-09-28T23:59:59.000Z

422

On the Quantum-Corrected Black Hole Thermodynamics

Bekenstein-Hawking Black hole thermodynamics should be corrected to incorporate quantum gravitational effects. Generalized Uncertainty Principle(GUP) provides a perturbational framework to perform such modifications. In this paper we consider the most general form of GUP to find black holes thermodynamics in microcanonical ensemble. Our calculation shows that there is no logarithmic pre-factor in perturbational expansion of entropy. This feature will solve part of controversies in literatures regarding existence or vanishing of this pre-factor.

Kourosh Nozari; S. Hamid Mehdipour

2005-04-21T23:59:59.000Z

423

The synchrotron boiler and the spectral states of black hole binaries

We study the effects of synchrotron self-absorption on the Comptonising electron distribution in the magnetised corona of accreting black holes. We solve the kinetic equations assuming that power is supplied to the coronal electrons through Coulomb collisions with a population of hot protons and/or through the injection of non-thermal energetic electrons by some unspecified acceleration process. We compute numerically the steady state particle distributions and escaping photon spectra. These numerical simulations confirm that synchrotron self-absorption, together with e-e Coulomb collisions, constitute an efficient thermalising mechanism for the coronal electrons. When compared to the data, they allow us to constrain the magnetic field and temperature of the hot protons in the corona independently of any dynamical accretion flow model or geometry. A preliminary comparison with the Low Hard State (LHS) spectrum of Cygnus X-1 indicates a magnetic field below equipartition with radiation, suggesting that the cor...

Malzac, Julien

2008-01-01T23:59:59.000Z

424

Role of electric charge in shaping equilibrium configurations of fluid tori encircling black holes

Astrophysical fluids may acquire nonzero electrical charge because of strong irradiation or charge separation in a magnetic field. In this case, electromagnetic and gravitational forces may act together and produce new equilibrium configurations, which are different from the uncharged ones. Following our previous studies of charged test particles and uncharged perfect fluid tori encircling compact objects, we introduce here a simple test model of a charged perfect fluid torus in strong gravitational and electromagnetic fields. In contrast to ideal magnetohydrodynamic models, we consider here the opposite limit of negligible conductivity, where the charges are tied completely to the moving matter. This is an extreme limiting case which can provide a useful reference against which to compare subsequent more complicated astrophysically motivated calculations. To clearly demonstrate the features of our model, we construct three-dimensional axisymmetric charged toroidal configurations around Reissner-Nordstroem black holes and compare them with equivalent configurations of electrically neutral tori.

Kovar, Jiri; Slany, Petr; Stuchlik, Zdenek; Karas, Vladimir; Cremaschini, Claudio; Miller, John C. [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava Bezrucovo nam. 13, CZ-74601 Opava (Czech Republic); Astronomical Institute, Academy of Sciences, Bocni II, CZ-14131 Prague (Czech Republic); SISSA and INFN, Via Bonomea 265, I-34136 Trieste (Italy); SISSA and INFN, Via Bonomea 265, I-34136 Trieste, Italy and Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)

2011-10-15T23:59:59.000Z

425

A Simple Derivation of Finite-Temperature CFT Correlators from the BTZ Black Hole

We present a simple Lie-algebraic approach to momentum-space two-point functions of two-dimensional conformal field theory at finite temperature dual to the BTZ black hole. Making use of the real-time prescription of AdS/CFT correspondence and ladder equations of the Lie algebra $\\mathfrak{so}(2,2) \\cong \\mathfrak{sl}(2,\\mathbb{R})_{L} \\oplus \\mathfrak{sl}(2,\\mathbb{R})_{R}$, we show that the finite-temperature two-point functions in momentum space satisfy linear recurrence relations with respect to the left and right momenta. These recurrence relations are exactly solvable and completely determine the momentum-dependence of retarded and advanced two-point functions of finite-temperature conformal field theory.

Satoshi Ohya

2013-12-27T23:59:59.000Z

426

A Simple Derivation of Finite-Temperature CFT Correlators from BTZ Black Hole

We present a simple Lie-algebraic approach to momentum-space two-point functions of two-dimensional conformal field theory at finite temperature dual to the BTZ black hole. Making use of the real-time prescription of AdS/CFT correspondence and ladder equations of the Lie algebra $\\mathfrak{so}(2,2) \\cong \\mathfrak{sl}(2,\\mathbb{R})_{L} \\oplus \\mathfrak{sl}(2,\\mathbb{R})_{R}$, we show that the finite-temperature two-point functions in momentum space satisfy linear recurrence relations with respect to the left and right momenta. These recurrence relations are exactly solvable and completely determine the momentum-dependence of retarded and advanced two-point functions of finite-temperature conformal field theory.

Ohya, Satoshi

2013-01-01T23:59:59.000Z

427

Woods Hole Research Center Wind Turbine | Open Energy Information

Hole Research Center Wind Turbine Hole Research Center Wind Turbine Jump to: navigation, search Name Woods Hole Research Center Wind Turbine Facility Woods Hole Research Center Wind Turbine Sector Wind energy Facility Type Small Scale Wind Facility Status In Service Owner Woods Hole Research Center Developer Sustainable Energy Developments Energy Purchaser Woods Hole Research Center Location Falmouth MA Coordinates 41.548637Â°, -70.64326Â° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":41.548637,"lon":-70.64326,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

428

Nearly extremal apparent horizons in simulations of merging black holes

The spin angular momentum $S$ of an isolated Kerr black hole is bounded by the surface area $A$ of its apparent horizon: $8\\pi S \\le A$, with equality for extremal black holes. In this paper, we explore the extremality of individual and common apparent horizons for merging, rapidly spinning binary black holes. We consider simulations of merging black holes with equal masses $M$ and initial spin angular momenta aligned with the orbital angular momentum, including new simulations with spin magnitudes up to $S/M^2 = 0.994$. We measure the area and (using approximate Killing vectors) the spin on the individual and common apparent horizons, finding that the inequality $8\\pi S extremality by computing the smallest value that Booth and Fairhurst's extremality parameter can take for any scaling. Using this lower bound, we conclude that the common horizons are at least moderately close to extremal just after they appear. Finally, following Lovelace et al. (2008), we construct quasiequilibrium binary-black-hole initial data with "overspun" marginally trapped surfaces with $8\\pi S > A$ and for which our lower bound on their Booth-Fairhurst extremality exceeds unity. These superextremal surfaces are always surrounded by marginally outer trapped surfaces (i.e., by apparent horizons) with $8\\pi Sextremality lower bound on the enclosing apparent horizon is always less than unity but can exceed the value for an extremal Kerr black hole. (Abstract abbreviated.)

Geoffrey Lovelace; Mark A. Scheel; Robert Owen; Matthew Giesler; Reza Katebi; Bela Szilagyi; Tony Chu; Nicholas Demos; Daniel A. Hemberger; Lawrence E. Kidder; Harald P. Pfeiffer; Nousha Afshari

2014-11-26T23:59:59.000Z

429

Black Hole Instabilities and Exponential Growth

Recently, a general analysis has been given of the stability with respect to axisymmetric perturbations of stationary-axisymmetric black holes and black branes in vacuum general relativity in arbitrary dimensions. It was shown that positivity of canonical energy on an appropriate space of perturbations is necessary and sufficient for stability. However, the notions of both "stability" and "instability" in this result are significantly weaker than one would like to obtain. In this paper, we prove that if a perturbation of the form $\\pounds_t \\delta g$---with $\\delta g$ a solution to the linearized Einstein equation---has negative canonical energy, then that perturbation must, in fact, grow exponentially in time. The key idea is to make use of the $t$- or ($t$-$\\phi$)-reflection isometry, $i$, of the background spacetime and decompose the initial data for perturbations into their odd and even parts under $i$. We then write the canonical energy as $\\mathscr E\\ = \\mathscr K + \\mathscr U$, where $\\mathscr K$ and $...

Prabhu, Kartik

2015-01-01T23:59:59.000Z

430

U.S. Energy Information Administration (EIA) Indexed Site

B B l a c k H i l l s R e g io n Northern Anthracite Field S o u t h e r n A n t h r a c i t e F i e l d E. Middle Anthracite F ield Rhode Island Meta-Anthrac ite Terling ua Coal Field Coos Bay Coal Field Turtle Montain Coal Field North Central Coal Region San Juan Basin G u l f C o a s t C o a l R e g i o n Ft. Union Coal Re gion (Willist on Basin) Northern Appalachian Ba sin Powder Rive r Ba sin Uinta Basin Cheroke e P la tform Ce nt ra l Appalachian Ba sin Gr ea te r Gr ee n Ri ve r Ba si n T e r t i a r y L a k e B e d s R e g i o n Arkom a Ba sin Pic eance Ba sin Big Horn Ba sin Wind River Ba sin R a to n B as in Black Mesa Basin Taylorville Basin D e e p R i v e r B a s i n N. & Mid. Park Basins C u l p e p p e r B a s in Ha nna -Carbon Ba sin J a c k s o n H o le C o a l F ie ld He nr y Mo u nta ins Co al F iel d Rock Creek Coal Field Glacier Coal Field Goshen Hole Coal Field D a n R i v e r - D a n v i l l e B a s i n Goose Creek Field

431

We report on polarization-resolved photoluminescence studies of diverse excitonic complexes formed in GaAs quantum wells with a high-mobility two-dimensional hole gas in magnetic fields up to 23 T. Using two-beam illumination we decrease the hole concentration beyond the point of conversion from p- to n-type structures. We have demonstrated charge conversion between positive and negative exciton complexes (both free and bound to acceptors in the well). The switch between the electron and hole gases allowed us to distinguish between the emission lines from positive trions moving almost freely in the quantum well and bound to ionized acceptors in the barrier, which indicate their coexistence in the same well.

Jadczak, J.; Bryja, L.; Misiewicz, J.; Wójs, A. [Institute of Physics, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland); Potemski, M. [Grenoble High Magnetic Field Laboratory, CNRS, 38-042 Grenoble (France); Liu, F.; Yakovlev, D. R.; Bayer, M. [Experimentelle Physik 2, Technische Universität Dortmund, D-44227 Dortmund (Germany); Reuter, D.; Wieck, A. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätstraße (Germany); Nicoll, C. A.; Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE (United Kingdom)

2013-12-04T23:59:59.000Z

432

New solutions are derived in the $2+1$ gravity which is coupled to $|{\\cal F}|^k$ type non-linear electric field in Maxwell Power theory with dilaton field. We obtain consistent solutions in general $k$ case. We also investigate the behavior of the metric function with the space-time singularity. Then, we found some black hole solutions when the space-time has a singular point at $r=0$. Addition, we derive the Brown-York mass when the space-time represents black hole.

Masashi Kuniyasu

2015-01-27T23:59:59.000Z

433

Science Journals Connector (OSTI)

We present a microscopic theory of the magnetic field dependence of the optical properties of II–VI semiconductor quantum dots containing a single magnetic (Mn) impurity. The single-particle electron and heavy-hole states are described exactly by two-dimensional harmonic oscillators in a magnetic field, the Mn ion is treated as a spin of an isoelectronic impurity, and the quantum dot anisotropy is included perturbatively. The electron-hole direct, short-, and long-range exchange electron-hole Coulomb interactions, as well as the short-range spin-spin contact exchange interaction of the electron and the hole with the magnetic impurity is included. The electron-hole-Mn states are expanded in a finite number of configurations controlled by the number of confined electronic quantum dot shells and the full interacting Hamiltonian is diagonalized numerically in this basis. The absorption and emission spectrum is predicted as a function of photon energy, magnetic field, number of confined shells, and anisotropy. It is shown that the magnetic-field-induced enhancement of the exchange interaction of the Mn spin with the exciton is largely canceled by increased electron-hole Coulomb interactions. The predicted weak magnetic field dependence of the spacing of emission lines agrees well with the results of the spin model at low magnetic fields but differs at higher magnetic fields. Correlations in the exciton-Mn complex are predicted to determine absorption spectra.

Anna H. Trojnar; Marek Korkusi?ski; Marek Potemski; Pawel Hawrylak

2012-04-06T23:59:59.000Z

434

Ejection of hypervelocity stars by the (binary) black hole(s) in the Galactic center

We study three processes that eject hypervelocity (>10^3 km/s) stars from the Galactic center: (i) close encounters of two single stars; (ii) tidal breakup of binary stars by the central black hole, as originally proposed by Hills; and (iii) three-body interactions between a star and a binary black hole (BBH). Mechanism (i) expels hypervelocity stars to the solar radius at a negligible rate, ~10^{-11}/yr. Mechanism (ii) expels hypervelocity stars at a rate ~ 10^{-5}(\\eta/0.1)/yr, where \\eta is the fraction of stars in binaries with semimajor axis a_b<~0.3 AU. For solar-mass stars, the corresponding number of hypervelocity stars within the solar radius R_0=8 kpc is ~60(\\eta/0.1)(a_b/0.1 AU)^{1/2}. For mechanism (iii), Sgr A^* is assumed to be one component of a BBH. We constrain the allowed parameter space (semimajor axis, mass ratio) of the BBH. In the allowed region (for example, semimajor axis of 0.5x10^{-3} pc and mass ratio of 0.01), the rate of ejecting hypervelocity stars can be as large as ~10^{-4}/yr and the expected number of hypervelocity stars within the solar radius can be as large as ~10^3. Hypervelocity stars may be detectable by the next generation of large-scale optical surveys.

Qingjuan Yu; Scott Tremaine

2003-09-03T23:59:59.000Z

435

We calculate the emission from relativistic flows in black hole systems using a fully general relativistic radiative transfer formulation, with flow structures obtained by general relativistic magneto-hydrodynamic simulations. We consider thermal free-free emission and thermal synchrotron emission. Bright filament-like features protrude (visually) from the accretion disk surface, which are enhancements of synchrotron emission where the magnetic field roughly aligns with the line-of-sight in the co-moving frame. The features move back and forth as the accretion flow evolves, but their visibility and morphology are robust. We propose that variations and drifts of the features produce certain X-ray quasi-periodic oscillations (QPOs) observed in black-hole X-ray binaries.

Fuerst, Steven V.; /KIPAC, Menlo Park; Mizuno, Yosuke; /USRA, Huntsville; Nishikawa, Ken-Ichi; /USRA, Huntsville /Alabama U., Huntsville; Wu, Kinwah; /Mullard Space Sci.

2007-01-05T23:59:59.000Z

436

We present a new diagnostic allowing one to measure the anisotropy of ion temperatures and non-thermal velocities, as well as Doppler shifts with respect to the ambient magnetic field. This method provides new results, as well as an independent test for previous measurements obtained with other techniques. Our spectral data come from observations of a low-latitude, on-disk coronal hole. A potential field source surface model was used to calculate the angle between the magnetic field lines and the line of sight for each spatial bin of the observation. A fit was performed to determine the line widths and Doppler shifts parallel and perpendicular to the magnetic field. For each line width component we derived ion temperatures T {sub i,} and T {sub i, Parallel-To} and non-thermal velocities v {sub nt,} and v {sub nt, Parallel-To }. T {sub i,} was cooler than off-limb polar coronal hole measurements, suggesting increasing collisional cooling with decreasing height. T {sub i, Parallel-To} is consistent with a uniform temperature of (1.8 {+-} 0.2) Multiplication-Sign 10{sup 6} K for each ion. Since parallel ion heating is expected to be weak, this ion temperature should reflect the proton temperature. A comparison between our results and others implies a large proton temperature gradient around 1.02 R {sub Sun }. The non-thermal velocities are thought to be proportional to the amplitudes of various waves. Our results for v {sub nt,} agree with Alfven wave amplitudes inferred from off-limb polar coronal hole line width measurements. Our v {sub nt, Parallel-To} results are consistent with slow magnetosonic wave amplitudes inferred from Fourier analysis of time-varying intensity fluctuations. Doppler shift measurements yield outflows of Almost-Equal-To 5 km s{sup -1} for ions formed over a broad temperature range. This differs from other studies that found a strong Doppler shift dependence on formation temperature.

Hahn, M.; Savin, D. W. [Columbia Astrophysics Laboratory, Columbia University, MC 5247, 550 West 120th Street, New York, NY 10027 (United States)] [Columbia Astrophysics Laboratory, Columbia University, MC 5247, 550 West 120th Street, New York, NY 10027 (United States)

2013-02-15T23:59:59.000Z

437

Black hole firewalls, smoke and mirrors

Science Journals Connector (OSTI)

The radiation emitted by a black hole (BH) during its evaporation has to have some degree of quantum coherence to accommodate a unitary time evolution. We parametrize the degree of coherence by the number of coherently emitted particles Ncoh and show that it is severely constrained by the equivalence principle. We discuss, in this context, the fate of a shell of matter that falls into a Schwarzschild BH. Two points of view are considered: that of a stationary external observer and that of the shell itself. From the perspective of the shell, the near-horizon region has an energy density proportional to Ncoh2 in Schwarzschild units. So, if Ncoh is parametrically larger than the square root of the BH entropy SBH1/2, a firewall or more generally a “wall of smoke” forms and the equivalence principle is violated while the BH is still semiclassical. To have a degree of coherence that is parametrically smaller than SBH1/2, one has to introduce a new sub-Planckian gravitational length scale, which likely also violates the equivalence principle. And so our previously proposed model which has Ncoh=SBH1/2 is singled out. From the external-observer perspective, we find that the time it takes for the information about the state of the shell to get re-emitted from the BH is inversely proportional to Ncoh. When the rate of information release becomes of order unity, the semiclassical approximation starts to break down and the BH becomes a perfect reflecting information mirror.

Ram Brustein and A.?J.?M. Medved

2014-07-16T23:59:59.000Z

438

Discovering the QCD Axion with Black Holes and Gravitational Waves

Advanced LIGO will be the first experiment to detect gravitational waves. Through superradiance of stellar black holes, it may also be the first experiment to discover the QCD axion with decay constant above the GUT scale. When an axion's Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole, forming a "gravitational atom." Through the superradiance process, the number of axions occupying the bound levels grows exponentially, extracting energy and angular momentum from the black hole. Axions transitioning between levels of the gravitational atom and axions annihilating to gravitons produce observable gravitational wave signals. The signals are long-lasting, monochromatic, and can be distinguished from ordinary astrophysical sources. We estimate up to O(1) transition events at aLIGO for an axion between 10^-11 and 10^-10 eV and up to 10^4 annihilation events for an axion between 10^-13 and 10^-11 eV. In the event of a null search, aLIGO can constrain the axion mass as a function of the formation rate of rapidly spinning black holes. Axion annihilations are also promising for much lighter masses at future lower-frequency gravitational wave observatories, where we expect as many as $10^5$ events. Our projections for aLIGO are robust against perturbations from the black hole environment and account for our updated exclusion on the QCD axion of 6 * 10^-13 eV < ma < 2 * 10^-11 eV suggested by stellar black hole spin measurements.

Asimina Arvanitaki; Masha Baryakhtar; Xinlu Huang

2014-12-15T23:59:59.000Z

439

Electronic structure of diluted magnetic semiconductor superlattices: In-plane magnetic field effect

Science Journals Connector (OSTI)

The electronic structure of diluted magnetic semiconductor (DMS) superlattices under an in-plane magnetic field is studied within the framework of the effective-mass theory; the strain effect is also included in the calculation. The numerical results show that an increase of the in-plane magnetic field renders the DMS superlattice from the direct band-gap system to the indirect band-gap system, and spatially separates the electron and the hole by changing the type-I band alignment to a type-II band alignment. The optical transition probability changes from type I to type II and back to type I like at large magnetic field. This phenomenon arises from the interplay among the superlattice potential profile, the external magnetic field, and the sp-d exchange interaction between the carriers and the magnetic ions. The shear strain induces a strong coupling of the light- and heavy-hole states and a transition of the hole ground states from “light”-hole to “heavy”-hole-like states.

Hai-Bin Wu, Kai Chang, and Jian-Bai Xia

2002-04-22T23:59:59.000Z

440

The Arun field is a giant gas-condensate field operated by Mobil and Pertamina with over 20,000 acres of closure at the top of the Arun reservoir. A middle-shelf patch reef complex of early to middle Miocene age is the producing facies at the Arun field. About 1,100 ft of porous limestones, encased in shales, create a stratigraphic trap for overpressure hydrocarbons. Three main carbonate lithologies were encountered during the examination of over 4,300 ft of core; (1) a reef facies consisting of vuggy, coral encrusting, red-algal boundstones, (2) a near-reef facies consisting of foraminiferal, mixed-skeletal packstones with gravel-size coral fragments, and (3) an interreef lagoonal facies consisting of benthonic-foram packstones. Twenty-two species of corals have been identified from Arun reef facies; major reef-forming coals, listed in order of decreasing abundance, are Porites cf P. Lutes, Cyphastrea microphthalma, Astreopora myriophthalma, Styloconiella gunetheri, Porites solida, and Acropora ssp. The Arun reef is comprised of limestones (with minor amounts of dolomite). No shale beds occur in the sequence, and all carbonate facies are in communication. A pervasive microporosity, occurring throughout the Arun Limestone, results from meteoric alteration of original carbonate mud to form a microrhombic porosity that accounts for about three-fourths of the field's total porosity.

Jordan, C.F. Jr.; Abdullah, M.

1988-01-01T23:59:59.000Z

While these samples are representative of the content of NLE

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of NLE

to obtain the most current and comprehensive results.

441

The ecology of star clusters and intermediate mass black holes in the Galactic bulge

We simulate the inner 100pc of the Milky-Way Galaxy to study the formation and evolution of the population of star clusters and intermediate mass black holes. For this study we perform extensive direct N-body simulations of the star clusters which reside in the bulge, and of the inner few tenth of parsecs of the super massive black hole in the Galactic center. In our N-body simulations the dynamical friction of the star cluster in the tidal field of the bulge are taken into account via (semi)analytic soluations. The N-body calculations are used to calibrate a (semi)analytic model of the formation and evolution of the bulge. We find that about 10% of the clusters born within 100pc of the Galactic center undergo core collapse during their inward migration and form intermediate-mass black holes (IMBHs) via runaway stellar merging. After the clusters dissolve, these IMBHs continue their inward drift, carrying a few of the most massive stars with them. We predict that region within about 10 parsec of the SMBH is populated by about 50IMBHs of some 1000Msun. Several of these are expected to be accompanied still by some of the most massive stars from the star cluster. We also find that within a few milliparsec of the SMBH there is a steady population of several IMBHs. This population drives the merger rate between IMBHs and the SMBH at a rate of about one per 10Myr, sufficient to build the accumulate majority of mass of the SMBH. Mergers of IMBHs with SMBHs throughout the universe are detectable by LISA, at a rate of about two per week.

Simon Portegies Zwart; Holger Baumgardt; Stephen L. W. McMillan; Junichiro Makino; Piet Hut; Toshi Ebisuzaki

2005-12-05T23:59:59.000Z

442

The Extended Power Law as Intrinsic Signature For a Black Hole

We analyze the exact general relativistic exact integro-differential equation of radiative transfer describing the interaction of low energy photons with a Maxwellian distribution of hot electrons in gravitational field of a Schwarzschild black hole. We prove that due to Comptonization an initial arbitrary spectrum of low energy photons unavoidably results in spectra characterized by an extended power-law feature. We examine the spectral index by using both analytical and numerical methods for a variety of physical parameters as such the plasma temperature and the mass accretion rate. The presence of the event horizon as well as the behaviour of the null geodesics in its vicinity largely determine the dependence of the spectral index on the flow parameters. We come to the conclusion that the bulk motion of a converging flow is more efficient in upscattering photons than thermal Comptonization provided that the electron temperature in the flow is of order of a few keV or less. In this case, the spectrum observed at infinity consists of a soft component produced by those input photons that escape after a few scatterings without any significant energy change and of hard component (described by a power law) produced by the photons that underwent significant upscattering. The luminosity of the power-law component is relatively small compared to that of the soft component. For accretion into black hole the spectral energy index of the power-law is always higher than one for plasma temperature of order of a few keV. This result suggests that the bulk motion Comptonization might be responsible for the power-law spectra seen in the black-hole X-ray sources.

Lev Titarchuk; Thomas Zannias

1997-08-27T23:59:59.000Z

443

The Effect of Transition Region Heating on the Solar Wind from Coronal Holes

Science Journals Connector (OSTI)

Using a 16 moment solar wind model extending from the chromosphere to 1 AU, we study how the solar wind is affected by direct deposition of energy in the transition region, in both radially expanding geometries and rapidly expanding coronal holes. Energy is required in the transition region to lift the plasma up to the corona, where additional coronal heating takes place. The amount of energy deposited determines the transition region pressure and the number of particles reaching the corona and, hence, how the solar wind energy flux is divided between gravitational potential and kinetic energy. We find that when only protons are heated perpendicularly to the magnetic field in a rapidly expanding coronal hole, the protons quickly become collisionless and therefore conduct very little energy into the transition region, leading to a wind much faster than what is observed. Only by additional deposition of energy in the transition region can a reasonable mass flux and flow speed at 1 AU be obtained. Radiative loss in the transition region is negligible in these low-mass flux solutions. In a radially expanding geometry the same form of coronal heating results in a downward heat flux to the transition region substantially larger than what is needed to heat the upwelling plasma, resulting in a higher transition region pressure, a slow, massive solar wind, and radiative loss playing a dominant role in the transition region energy budget. No additional energy input is needed in the transition region in this case. In the coronal hole geometry the solar wind response to transition region heating is highly nonlinear, and even a tiny input of energy can have a very large influence on the asymptotic properties of the wind. By contrast, the radially expanding wind is quite insensitive to additional deposition of energy in the transition region.

Øystein Lie-Svendsen; Viggo H. Hansteen; Egil Leer; Thomas E. Holzer

2002-01-01T23:59:59.000Z

444

Scalar Field Quantum Inequalities in Static Spacetimes

We discuss quantum inequalities for minimally coupled scalar fields in static spacetimes. These are inequalities which place limits on the magnitude and duration of negative energy densities. We derive a general expression for the quantum inequality for a static observer in terms of a Euclidean two-point function. In a short sampling time limit, the quantum inequality can be written as the flat space form plus subdominant correction terms dependent upon the geometric properties of the spacetime. This supports the use of flat space quantum inequalities to constrain negative energy effects in curved spacetime. Using the exact Euclidean two-point function method, we develop the quantum inequalities for perfectly reflecting planar mirrors in flat spacetime. We then look at the quantum inequalities in static de~Sitter spacetime, Rindler spacetime and two- and four-dimensional black holes. In the case of a four-dimensional Schwarzschild black hole, explicit forms of the inequality are found for static observers near the horizon and at large distances. It is show that there is a quantum averaged weak energy condition (QAWEC), which states that the energy density averaged over the entire worldline of a static observer is bounded below by the vacuum energy of the spacetime. In particular, for an observer at a fixed radial distance away from a black hole, the QAWEC says that the averaged energy density can never be less than the Boulware vacuum energy density.

Michael J. Pfenning; L. H. Ford

1997-10-09T23:59:59.000Z

445

Instability of wormholes supported by a ghost scalar field. II. Nonlinear evolution

We analyze the nonlinear evolution of spherically symmetric wormhole solutions coupled to a massless ghost scalar field using numerical methods. In a previous article we have shown that static wormholes with these properties are unstable with respect to linear perturbations. Here we show that depending on the initial perturbation the wormholes either expand or decay to a Schwarzschild black hole. We estimate the time scale of the expanding solutions and the ones collapsing to a black hole and show that they are consistent in the regime of small perturbations with those predicted from perturbation theory. In the collapsing case, we also present a systematic study of the final black hole horizon and discuss the possibility for a luminous signal to travel from one universe to the other and back before the black hole forms. In the expanding case, the wormholes seem to undergo an exponential expansion, at least during the run time of our simulations.

J. A. Gonzalez; F. S. Guzman; O. Sarbach

2008-06-09T23:59:59.000Z

446

Probing Core-Hole Localization in Molecular Nitrogen

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Probing Core-Hole Localization Probing Core-Hole Localization in Molecular Nitrogen Probing Core-Hole Localization in Molecular Nitrogen Print Wednesday, 25 February 2009 00:00 The behavior of the core hole created in molecular x-ray photoemission experiments has provided molecular scientists with a valuable window through which to probe the electronic structure and dynamics of molecules. But the answer to one fundamental quantum question-whether the core hole is localized or delocalized-has remained elusive for diatomic molecules in which both atoms are the same element. An international team of scientists from the University of Frankfurt in Germany, Berkeley Lab, Kansas State University, and Auburn University has now resolved the issue with an appropriate twist of quantum fuzziness. By means of coincident detection of the photoelectron ejected from molecular nitrogen and the Auger electron emitted femtoseconds later, the team found that how the measurements are done determines which description-localized or delocalized-is valid.

447

Slim hole drilling proven in remote exploration project

This paper reports on a helicopter-supported slim hole exploration project in a remote tropical forest which cost 15% less than a conventional drilling operation. The potential savings after improvements in rig equipment, bits, and drilling and coring methods may approach 30%. Because of the small size of the slim hole equipment, the impact on the rain forest was small. The areas cleared for locations and access during the operation were 75% less than that required for similar operations with conventional road-transported rigs. During the second half of 1991, Total Exploration Gabon, a subsidiary of Total Exploration Production, conducted a slim hole drilling project in the Gabonese tropical rain forest in a joint venture with Chevron Corp., Exxon Corp., and Austria's OMV AG. During this helicopter-supported operation, two wells were drilled: one to 2,747 m (9,010 ft) ending with a 3 in. hole and one to 418 m (1,371 ft) ending with a 5-7/8 in. hole. Continuous coring operations recovered 1,868 m (6,127 ft), or 59% of the total length drilled.

Dachary, J. (Total Exploration Production, Libreville (GA)); Vighetto, R. (Total Exploration Production, Paris (FR))

1992-06-22T23:59:59.000Z

448

Microhole Coiled Tubing Bottom Hole Assemblies

The original objective of the project, to deliver an integrated 3 1/8-inch diameter Measurement While Drilling (MWD) and Logging While Drilling (LWD) system for drilling small boreholes using coiled tubing drilling, has been achieved. Two prototype systems have been assembled and tested in the lab. One of the systems has been successfully tested downhole in a conventional rotary drilling environment. Development of the 3 1/8-inch system has also lead to development and commercialization of a slightly larger 3.5-inch diameter system. We are presently filling customer orders for the 3.5-inch system while continuing with commercialization of the 3 1/8-inch system. The equipment developed by this project will be offered for sale to multiple service providers around the world, enabling the more rapid expansion of both coiled tubing drilling and conventional small diameter drilling. The project was based on the reuse of existing technology whenever possible in order to minimize development costs, time, and risks. The project was begun initially by Ultima Labs, at the time a small company ({approx}12 employees) which had successfully developed a number of products for larger oil well service companies. In September, 2006, approximately 20 months after inception of the project, Ultima Labs was acquired by Sondex plc, a worldwide manufacturer of downhole instrumentation for cased hole and drilling applications. The acquisition provided access to proven technology for mud pulse telemetry, downhole directional and natural gamma ray measurements, and surface data acquisition and processing, as well as a global sales and support network. The acquisition accelerated commercialization through existing Sondex customers. Customer demand resulted in changes to the product specification to support hotter (150 C) and deeper drilling (20,000 psi pressure) than originally proposed. The Sondex acquisition resulted in some project delays as the resistivity collar was interfaced to a different MWD system and also as the mechanical design was revised for the new pressure requirements. However, the Sondex acquisition has resulted in a more robust system, secure funding for completion of the project, and more rapid commercialization.

Don Macune

2008-06-30T23:59:59.000Z

449

Compact boson stars in K field theories

We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.

C. Adam; N. Grandi; P. Klimas; J. Sanchez-Guillen; A. Wereszczynski

2009-09-16T23:59:59.000Z

450

Compact boson stars in K field theories

We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.

Adam, C; Klimas, P; Sánchez-Guillén, J; Wereszczynski, A

2009-01-01T23:59:59.000Z

451

General relativistic simulations of black-hole-neutron-star mergers: Effects of black-hole spin

Black-hole-neutron-star (BHNS) binary mergers are candidate engines for generating both short-hard gamma-ray bursts and detectable gravitational waves. Using our most recent conformal thin-sandwich BHNS initial data and our fully general relativistic hydrodynamics code, which is now adaptive mesh refinement capable, we are able to efficiently and accurately simulate these binaries from large separations through inspiral, merger, and ringdown. We evolve the metric using the Baumgarte-Shapiro-Shibata-Nakamura formulation with the standard moving puncture gauge conditions, and handle the hydrodynamics with a high-resolution shock-capturing scheme. We explore the effects of BH spin (aligned and antialigned with the orbital angular momentum) by evolving three sets of initial data with BH:NS mass ratio q=3: the data sets are nearly identical, except the BH spin is varied between a/M{sub BH}=-0.5 (antialigned), 0.0, and 0.75. The number of orbits before merger increases with a/M{sub BH}, as expected. We also study the nonspinning BH case in more detail, varying q between 1, 3, and 5. We calculate gravitational waveforms for the cases we simulate and compare them to binary black-hole waveforms. Only a small disk (<0.01M{sub {center_dot}}) forms for the antialigned spin case (a/M{sub BH}=-0.5) and for the most extreme-mass-ratio case (q=5). By contrast, a massive (M{sub disk}{approx_equal}0.2M{sub {center_dot}}) hot disk forms in the rapidly spinning (a/M{sub BH}=0.75) aligned BH case. Such a disk could drive a short-hard gamma-ray burst, possibly by, e.g., producing a copious flux of neutrino-antineutrino pairs.

Etienne, Zachariah B.; Liu, Yuk Tung; Shapiro, Stuart L. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Baumgarte, Thomas W. [Department of Physics and Astronomy, Bowdoin College, Brunswick, Maine 04011 (United States)

2009-02-15T23:59:59.000Z

452

Universality of critical magnetic field in holographic superconductor

Holographic superconductors with constant external magnetic field have been investigated by analytical matching method. It has been shown that the critical temperature and critical magnetic field can be calculated in non-zero temperature. Meissner effect has been observed in such superconductors. The relationship between normal entropy mode and superconductor with Bekenstein upper bound has been studied. Universal relation between black hole mass $ M$ and critical magnetic field $H_c$ has been proposed as $\\frac{H_c}{M^{2/3}}\\leq 0.60045$.

Davood Momeni; Ratbay Myrzakulov

2014-01-13T23:59:59.000Z

453

Greybody factor for D3-branes in a B field

Science Journals Connector (OSTI)

We calculate the effect of noncommutative spacetime on the greybody factor on the supergravity side. For this purpose we introduce a system of D3-branes with a constant NS B field along their world volume directions (x2,x3). Considering the propagation of a minimally coupled scalar with nonzero momentum along (x2,x3), we derive an exact form of the greybody factor in the B field. It turns out that ?lB?0>?lB=0. This means that the presence of the B field (the noncommutativity) suppresses the potential barrier surrounding the black hole. As a result, the greybody factor increases.

Y. S. Myung; Gungwon Kang; H. W. Lee

2000-07-24T23:59:59.000Z

454

Self-force on a charge outside a five-dimensional black hole

We compute the electromagnetic self-force acting on a charged particle held in place at a fixed position r outside a five-dimensional black hole described by the Schwarzschild-Tangherlini metric. Using a spherical-harmonic decomposition of the electrostatic potential and a regularization prescription based on the Hadamard Green's function, we express the self-force as a convergent mode sum. The self-force is first evaluated numerically, and next presented as an analytical expansion in powers of R/r, with R denoting the event-horizon radius. The power series is then summed to yield a closed-form expression. Unlike its four-dimensional version, the self-force features a dependence on a regularization parameter s that can be interpreted as the particle's radius. The self-force is repulsive at large distances, and its behavior is related to a model according to which the force results from a gravitational interaction between the black hole and the distribution of electrostatic field energy attached to the particle. The model, however, is shown to become inadequate as r becomes comparable to R, where the self-force changes sign and becomes attractive. We also calculate the self-force acting on a particle with a scalar charge, which we find to be everywhere attractive. This is to be contrasted with its four-dimensional counterpart, which vanishes at any r.

Matthew J. S. Beach; Eric Poisson; Bernhard G. Nickel

2014-04-03T23:59:59.000Z

455

Electron Acceleration around the Supermassive Black Hole at the Galactic Center

The recent detection of variable infrared emission from Sagittarius A*, combined with its previously observed flare activity in X-rays, provides compelling evidence that at least a portion of this object's emission is produced by nonthermal electrons. We show here that acceleration of electrons by plasma wave turbulence in hot gases near the black hole's event horizon can account both for Sagittarius A*'s mm and shorter wavelengths emission in the quiescent state, and for the infrared and X-ray flares, induced either via an enhancement of the mass accretion rate onto the black hole or by a reorganization of the magnetic field coupled to the accretion gas. The acceleration model proposed here produces distinct flare spectra that may be compared with future coordinated multi-wavelength observations. We further suggest that the diffusion of high energy electrons away from the acceleration site toward larger radii might be able to account for the observed characteristics of Sagittarius A*'s emission at cm and longer wavelengths.

Siming Liu; Vahe' Petrosian; Fulvio Melia

2004-03-19T23:59:59.000Z

456

String dynamics and ejection along the axis of a spinning black hole

Science Journals Connector (OSTI)

Relativistic current carrying strings moving axisymmetrically on the background of a Kerr black hole are studied. The boundaries and possible types of motion of a string with a given energy and current are found. Regions of parameters for which the string falls into the black hole, is trapped in a toroidal volume, or can escape to infinity, are identified, and representative trajectories are examined by numerical integration, illustrating various interesting behaviors. In particular, we find that a string can start out at rest near the equatorial plane and, after bouncing around, be ejected out along the axis, some of its internal (elastic or rotational kinetic) energy having been transformed into translational kinetic energy. The resulting velocity can be an order unity fraction of the speed of light. This process results from the presence of an outer tension barrier and an inner angular momentum barrier that are deformed by the gravitational field. We speculatively discuss the possible astrophysical significance of this mechanism as a means of launching a collimated jet of magnetohydrodynamics plasma flux tubes along the spin axis of a gravitating system fed by an accretion disk.

Ted Jacobson and Thomas P. Sotiriou

2009-03-26T23:59:59.000Z

457

The Black-Hole Mass in M87 from Gemini/NIFS Adaptive Optics Observations

We present the stellar kinematics in the central 2" of the luminous elliptical galaxy M87 (NGC 4486), using laser adaptive optics to feed the Gemini telescope integral-field spectrograph, NIFS. The velocity dispersion rises to 480 km/s at 0.2". We combine these data with extensive stellar kinematics out to large radii to derive a black-hole mass equal to (6.6+-0.4)x10^9 Msun, using orbit-based axisymmetric models and including only the NIFS data in the central region. Including previously-reported ground-based data in the central region drops the uncertainty to 0.25x10^9 Msun with no change in the best-fit mass; however, we rely on the values derived from the NIFS-only data in the central region in order to limit systematic differences. The best-fit model shows a significant increase in the tangential velocity anisotropy of stars orbiting in the central region with decreasing radius; similar to that seen in the centers of other core galaxies. The black-hole mass is insensitive to the inclusion of a dark halo ...

Gebhardt, Karl; Richstone, Douglas; Lauer, Tod R; Faber, S M; Gultekin, Kayhan; Murphy, Jeremy; Tremaine, Scott

2011-01-01T23:59:59.000Z

458

Properties of radiation near the black-hole horizon and the second law of thermodynamics

Science Journals Connector (OSTI)

By considering a gedanken experiment of adiabatically lowering a box containing matter with rest energy E and entropy S into a black hole, Bekenstein claimed that the necessary condition for the validity of the generalized second law of thermodynamics is S/E?2?R, where R is the effective radius of the box. Unruh and Wald claimed that this condition is not necessary but the acceleration radiation can guarantee the generalized second law. In this paper, we point out that the Unruh-Wald conclusion does not hold because Hawking radiation near the horizon is not thermal. Bekenstein’s conclusion does not hold because the thin box approximation is not correct near the horizon. Neither Hawking radiation (or acceleration radiation) nor S/E?2?R can guarantee the second law. We have sufficient reasons to conjecture that gravitation can influence the matter equation of state. For radiation, the usual equation of state ?=?T4 and S=4/3?T3 does not hold in the strong gravitation field, e.g., near the black-hole horizon. We derive the equation of state for radiation near the horizon and find that it is very different from the equation in flat spacetime. The second law of thermodynamics can be satisfied if we impose some restrictions on one parameter of the equation of state. As a corollary, we get an upper bound on S/E which resembles Bekenstein’s result.

Li-Xin Li and Liao Liu

1992-10-15T23:59:59.000Z

459

National Nuclear Security Administration (NNSA)

about NNSS

460

T-623: HP Business Availability Center Input Validation Hole Permits

Broader source: Energy.gov (indexed) [DOE]

3: HP Business Availability Center Input Validation Hole 3: HP Business Availability Center Input Validation Hole Permits Cross-Site Scripting Attacks T-623: HP Business Availability Center Input Validation Hole Permits Cross-Site Scripting Attacks May 16, 2011 - 3:05pm Addthis PROBLEM: A vulnerability was reported in HP Business Availability Center. A remote user can conduct cross-site scripting attacks. PLATFORM: HP Business Availability Center software 8.06 and prior versions ABSTRACT: The software does not properly filter HTML code from user-supplied input before displaying the input. reference LINKS: SecurityTracker Alert ID:1025535 HP Knowledge Base CVE-2011-1856 Secunia ID: SA44569 HP Document ID:c02823184 | ESB-2011.0525 IMPACT ASSESSMENT: High Discussion: A remote user can cause arbitrary scripting code to be executed by the

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461

Information consumption by Reissner-Nordström black holes

Science Journals Connector (OSTI)

The low-energy scattering of charged fermions by extremal magnetic Reissner-Nordström black holes is analyzed in the large-N and S-wave approximations. It is shown that (in these approximations) information is carried into a causally inaccessible region of spacetime, and thereby effectively lost. It is also shown that there is an infinite degeneracy of quantum black hole ground states, or "remnants," which store, but will not reveal, the information. A notable feature of the analysis, not shared by recent analyses of dilatonic black holes, is that the key physical questions can be answered within the weak coupling domain. We regard these results as strong evidence that effective information loss occurs in our Universe.

Andrew Strominger and Sandip P. Trivedi

1993-12-15T23:59:59.000Z

462

Regular Black Hole Metric with Three Constants of Motion

According to the no-hair theorem, astrophysical black holes are uniquely characterized by their masses and spins and are described by the Kerr metric. Several parametric spacetimes which deviate from the Kerr metric have been proposed in order to test this theorem with observations of black holes in both the electromagnetic and gravitational-wave spectra. Such metrics often contain naked singularities or closed timelike curves in the vicinity of the compact objects that can limit the applicability of the metrics to compact objects that do not spin rapidly, and generally admit only two constants of motion. The existence of a third constant, however, can facilitate the calculation of observables, because the equations of motion can be written in first-order form. In this paper, I design a Kerr-like black hole metric which is regular everywhere outside of the event horizon, possesses three independent constants of motion, and depends nonlinearly on four free functions that parameterize potential deviations from ...

Johannsen, Tim

2015-01-01T23:59:59.000Z

463

Modeling feedback from stars and black holes in galaxy mergers

We describe techniques for incorporating feedback from star formation and black hole accretion into simulations of isolated and merging galaxies. At present, the details of these processes cannot be resolved in simulations on galactic scales. Our basic approach therefore involves forming coarse-grained representations of the properties of the interstellar medium and black hole accretion starting from basic physical assumptions, so that the impact of these effects can be included on resolved scales. We illustrate our method using a multiphase description of star-forming gas. Feedback from star formation pressurises highly overdense gas, altering its effective equation of state. We show that this allows the construction of stable galaxy models with much larger gas fractions than possible in earlier numerical work. We extend the model by including a treatment of gas accretion onto central supermassive black holes in galaxies. Assuming thermal coupling of a small fraction of the bolometric luminosity of accreting...

Springel, V; Hernquist, L; Springel, Volker; Matteo, Tiziana Di; Hernquist, Lars

2004-01-01T23:59:59.000Z

464

Cloud of strings for radiating black holes in Lovelock gravity

We present exact spherically symmetric null dust solutions in the third order Lovelock gravity with a string cloud background in arbitrary $N$ dimensions,. This represents radiating black holes and generalizes the well known Vaidya solution to Lovelock gravity with a string cloud in the background. We also discuss the energy conditions and horizon structures, and explicitly bring out the effect of the string clouds on the horizon structure of black hole solutions for the higher dimensional general relativity and Einstein-Gauss-Bonnet theories. It turns out that the presence of the coupling constant of the Gauss-Bonnet terms and/or background string clouds completely changes the structure of the horizon and this may lead to a naked singularity. We recover known spherically symmetric radiating models as well as static black holes in the appropriate limits.

Sushant G. Ghosh; Sunil D. Maharaj

2014-09-28T23:59:59.000Z

465

Thermodynamic critical and geometrical properties of charged BTZ black hole

The heat capacities and the electric capacitances of charged Banados-Teitelboim-Zanelli (BTZ) black hole are first calculated. By using the equilibrium fluctuation theory of thermodynamics the second-order moments in three different ensembles are obtained, and it is found that in the microcanonical ensemble the extremal charged BTZ black hole is a critical point of the second-order phase transition. The critical exponents associated with some response coefficients satisfy the scaling law of the first kind and the effective spatial dimension is determined to be one from the scaling law of the second kind. The Ricci curvature scalar associated with the Ruppeiner thermodynamic metric is calculated, which suggests also that the effective spatial dimension of the charged BTZ black hole is one.

Wei Yihuan [Department of Physics, Bohai University, Jinzhou 121000, Liaoning (China)

2009-07-15T23:59:59.000Z

466

Advection-Dominated Accretion and the Black Hole Event Horizon

As the luminosity of an accreting black hole drops to a few percent of Eddington, the spectrum switches from the familiar soft state to a hard state that is well-described by a distended and tenuous advection-dominated accretion flow (ADAF). An ADAF is a poor radiator, and the ion temperature can approach 10^{12} K near the center, although the electrons are cooler, with their temperature typically capped at ~10^{9-11} K. The foundational papers predicted that the large thermal energy in an ADAF would drive strong winds and jets, as later observed and also confirmed in computer simulations. Of chief interest, however, is the accreting gas that races inward. It carries the bulk of the accretion energy as stored thermal energy, which vanishes without a trace as the gas passes through the hole's event horizon. One thus expects black holes in the ADAF regime to be unusually faint. Indeed, this is confirmed by a comparison of accreting stellar-mass black holes and neutron stars, which reside in very similar transient X-ray binary systems. The black holes are on average observed to be fainter by a factor of ~100-1000. The natural explanation is that a neutron star must radiate the advected thermal energy from its surface, whereas a black hole can hide the energy behind its event horizon. The case for an event horizon in Sagittarius A*, which is immune to caveats on jet outflows and is furthermore independent of the ADAF model, is especially compelling. These two lines of evidence for event horizons are impervious to counterarguments that invoke strong gravity or exotic stars.

Ramesh Narayan; Jeffrey E. McClintock

2008-03-03T23:59:59.000Z

467

Final Report Limited Soil Investigation of Project Chariot Test Holes

Office of Legacy Management (LM)

Limited Soil Investigation of Project Limited Soil Investigation of Project Chariot Test Holes Cape Thompson, Alaska December 2010 Prepared for U.S. Department of Energy and U.S. Army Corps of Engineers, Alaska District Post Office Box 6898 Elmendorf AFB, Alaska 99506-6898 Contract W911KB-08-D-0003 Task Order 12, Mod 001 Prepared by Fairbanks Environmental Services 3538 International Street Fairbanks, Alaska 99701 (907) 452-1006 FES Project No. 5012-06 Final Report Limited Soil Investigation of Project Chariot Test Holes, Cape Thompson, Alaska Fairbanks Environmental Services 5012-06 TABLE OF CONTENTS Page Number EXECUTIVE SUMMARY 1.0 INTRODUCTION ................................................................................................... 1-1

468

Automatic CNC Part Programming for through Hole Drilling

Science Journals Connector (OSTI)

Abstract This paper describes a novel method for automatic generation of process plans and numerical control (NC) part programs from STEP data files. Using proposed system, it is possible to achieve fully automation of recognition of through hole features, generation of process plans and NC part programs. Thus, it becomes possible to go from neutral file to finished product in a fully automated fashion. The algorithms have been implemented on mini-computer to process product data, and display recognized hole features, process plans and creates output files containing NC part programs. These NC part programs are tested through BMV45TC24 CNC Vertical Machining Centers. The results are satisfactory.

B.R. Borkar; Y.M. Puri; A.M. Kuthe; P.S. Deshpande

2014-01-01T23:59:59.000Z

469

Exploring higher dimensional black holes at the large hadron collider.

of extra dimensions. Throughout, we have used the ATLAS fast simulation software [20] to give a description of a typical detector and we have used the full simulation [21] to verify the main results. 2. Black hole production and decay In the black hole... evolution from present energies is questionable. Also, comparison to Standard Model pro- cesses in the trans-Planckian regime would be difficult since perturbative physics would be suppressed. 4.2 The first stages of decay CHARYBDIS does not model...

Harris, Chris M; Palmer, M J; Parker, Michael A; Richardson, P

470

Repairs for damaged bolt holes in continuous fiber reinforced plastics

repair method for damaged bolt holes in such composites. Bolt holes in three types of graphite-epoxy were purposely damaged and then repaired. Each was tested to characterize its static and fatigue behavior. The tests used a special fixture to simulate... composite joints . Bearing-bypass ratio can change the failure mode of bolted composite joints 7 Drilling defects in graphite-epoxy coupons 12 26 The exit side of a IM7/8551-7A 18 ply tape coupon showing the damage due to drilling 27 9 Resin filled...

Copps, Kevin Daniel

2012-06-07T23:59:59.000Z

471

A Commentary on Ruppeiner Metrics for Black Holes

There has been some recent controversy regarding the Ruppeiner metrics that are induced by Reissner-Nordstrom (and Reissner-Nordstrom-like) black holes. Most infamously, why does this family of metrics turn out to be flat, how is this outcome to be physically understood, and can/should the formalism be suitably modified to induce curvature? In the current paper, we provide a novel interpretation of this debate. For the sake of maximal analytic clarity and tractability, some supporting calculations are carried out for the relatively simple model of a rotating BTZ black hole.

A. J. M. Medved

2008-01-23T23:59:59.000Z

472

Black holes and black strings in plane waves

We investigate the construction of black holes and black strings in vacuum plane wave spacetimes using the method of matched asymptotic expansions. We find solutions of the linearised equations of motion in the asymptotic region for a general source on a plane wave background. We observe that these solutions do not satisfy our previously defined conditions for being asymptotically plane wave. Hence, the space of asymptotically plane wave solutions is restricted. We consider the solution in the near region, treating the plane wave as a perturbation of a black object, and find that there is a regular black string solution but no regular black hole solution.

Julian Le Witt; Simon F. Ross

2009-10-30T23:59:59.000Z

473

Using the uncharged Kerr black hole as a gravitational mirror

We extend the study of the possibility to use the Schwarzschild black hole as a gravitational mirror to the more general case of an uncharged Kerr black hole. We use the null geodesic equation in the equatorial plane to prove a theorem concerning the conditions the impact parameter has to satisfy if there shall exist boomerang photons. We derive an equation for these boomerang photons and an equation for the emission angle. Finally, the radial null geodesic equation is integrated numerically in order to illustrate boomerang photons.

Cramer, C R

1995-01-01T23:59:59.000Z

474

Using the Uncharged Kerr Black Hole as a Gravitational Mirror

We extend the study of the possibility to use the Schwarzschild black hole as a gravitational mirror to the more general case of an uncharged Kerr black hole. We use the null geodesic equation in the equatorial plane to prove a theorem concerning the conditions the impact parameter has to satisfy if there shall exist boomerang photons. We derive an equation for these boomerang photons and an equation for the emission angle. Finally, the radial null geodesic equation is integrated numerically in order to illustrate boomerang photons.

Claes R Cramer

1995-10-25T23:59:59.000Z

475

Stationary black-hole binaries: A non-existence proof

We resume former discussions of the question, whether the spin-spin repulsion and the gravitational attraction of two aligned black holes can balance each other. Based on the solution of a boundary problem for disconnected (Killing) horizons and the resulting violation of characteristic black hole properties, we present a non-existence proof for the equilibrium configuration in question. From a mathematical point of view, this result is a further example for the efficiency of the inverse ("scattering") method in non-linear theories.

Gernot Neugebauer; Jörg Hennig

2014-06-23T23:59:59.000Z

476

Slim Holes At Salt Wells Area (Combs, Et Al., 1999) | Open Energy

Slim Holes At Salt Wells Area (Combs, Et Al., 1999) Slim Holes At Salt Wells Area (Combs, Et Al., 1999) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Slim Holes At Salt Wells Area (Combs, Et Al., 1999) Exploration Activity Details Location Salt Wells Area Exploration Technique Slim Holes Activity Date 1980 - 1980 Usefulness useful DOE-funding Unknown Exploration Basis The blind Salt Wells geothermal system was first identified when Anadarko Petroleum Corporation drilled slim hole and geothermal exploration wells at the site in 1980. Two reports detail the results of this drilling activity. This report details the well completion practices applied to the initial slim hole discovery well. Notes In 1980, Anadarko Petroleum Corporation drilled a slim hole discovery well near Simpson Pass. The hole was initially rotary-drilled to 161.5 m for

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