Hoover, S.
2002-06-01T23:59:59.000Z
Studies have shown that raptors flying within the Altamont Pass WRA are vulnerable to fatal turbine collisions, possibly because of their specific foraging and flight behavior. Between June 1999 and June 2000, I conducted 346.5 hours of raptor observations within the Atlamont Pass WRA. Behavior was recorded in relation to characteristics of the topography (slope aspect, elevation, and inclination), the weather, and ground squirrel abundance, as determined by active burrow entrances. The most significant finding of this study revealed that red-tailed hawks and golden eagles flew more in strong winds than in weak winds, particularly along hillsides facing into prevailing winds (as opposed to hillsides shielded from the wind). This is likely a result of the birds' use of declivity currents for lift during flights. These results suggest that certain combinations of topography and weather produce wind currents that are sought out by foraging red-tailed hawks and golden eagles within the Altamont Pass WRA. To decrease raptor mortality, mitigation measures can be targeted to specific areas likely to attract foraging raptors because of their capacity to create particularly favorable wind currents.
None
2011-04-25T23:59:59.000Z
Le grand astrophysicien S.Hawking, né le 08-01-1942 à Oxford, parle de "baby universes" et la gravitation et répond aux questions.
Corson, Michael Scott
1996-01-01T23:59:59.000Z
, 1975, Zinkl et al. , 1978, ' Balcomb et al. , 1984; Flickinger et al. , 1984; Flickinger et al. , 1986; Elliott et al. , 1996) In the field of ecotoxicology, some scientists attempt to determine effects of pesticides and pollution at large... al. , 1981), red-shouldered hawks (Buteo linea/us) (Balcomb, 1983), red-tailed hawks (Bureoj amaicensi s) (Henny et al. , 1985), and laughing gulls (Larus arrici lla) (White et al. , 1979). In some cases, dietary exposure may pose the greatest risk...
Hawking radiation and Quasinormal modes
SangChul Yoon
2005-10-05T23:59:59.000Z
The spectrum of Hawking radiation by quantum fields in the curved spacetime is continuous, so the explanation of Hawking radiation using quasinormal modes can be suspected to be impossible. We find that quasinormal modes do not explain the relation between the state observed in a region far away from a black hole and the short distance behavior of the state on the horizon.
Has Hawking radiation been measured?
W. G. Unruh
2014-01-26T23:59:59.000Z
It is argued that Hawking radiation has indeed been measured and shown to posses a thermal spectrum, as predicted. This contention is based on three separate legs. The first is that the essential physics of the Hawking process for black holes can be modelled in other physical systems. The second is the white hole horizons are the time inverse of black hole horizons, and thus the physics of both is the same. The third is that the quantum emission, which is the Hawking process, is completely determined by measurements of the classical parameters of a linear physical system. The experiment conducted in 2010 fulfills all of these requirements, and is thus a true measurement of Hawking radiation.
Thermality of the Hawking flux
Matt Visser
2015-02-09T23:59:59.000Z
Is the Hawking flux "thermal"? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word "thermal". The original 1850's notions of thermality --- based on classical thermodynamic reasoning applied to idealized "black bodies" or "lamp black surfaces" --- when supplemented by specific basic quantum ideas from the early 1900's, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but "without" any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, and quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lump of coal), is only "approximately" Planck-shaped over a bounded frequency range. Standard physics (phase space and adiabaticity effects) explicitly bound the frequency range over which the Hawking flux is "approximately" Planck-shaped from both above and below --- the Hawking flux is certainly not exactly Planckian, and there is no compelling physics reason to assume the Hawking photons are uncorrelated.
Investigation of Operations of Hawk Pedestrian Treatment
Li, Siqi
2012-07-16T23:59:59.000Z
functional forms are investigated in order to select an appropriate one that could more accurately model pedestrian delay. The minimum green time for vehicles, as an important variable in the HAWK pedestrian delay model and a peculiar element in HAWK...
Hawking Emission and Black Hole Thermodynamics
Don N. Page
2006-12-18T23:59:59.000Z
A brief review of Hawking radiation and black hole thermodynamics is given, based largely upon hep-th/0409024.
Hawking radiation in moving plasmas
L. C. Garcia de Andrade
2005-09-07T23:59:59.000Z
Bi-metricity and Hawking radiation are exhibit in non-relativistic moving magnetohydrodynamics (MHD) plasma medium generating two Riemannian effective spacetimes. The first metric is a flat metric although the speed of "light" is given by a time dependent signal where no Hawking radiation or effective black holes are displayed. This metric comes from a wave equation which the scalar function comes from the scalar potential of the background velocity of the fluid and depends on the perturbation of the magnetic background field. The second metric is an effective spacetime metric which comes from the perturbation of the background MHD fluid. This Riemann metric exhibits a horizon and Hawking radiation which can be expressed in terms of the background constant magnetic field. The effective velocity is given Alfven wave velocity of plasma physics. The effective black hole found here is analogous to the optical black hole in moving dielectrics found by De Lorenci et al [Phys. Rev. D (2003)] where bi-metricity and Hawking radiation in terms of the electric field are found.
Local Approach to Hawking Radiation
Ari Peltola
2008-12-03T23:59:59.000Z
We consider an approach to the Hawking effect which is free of the asymptotic behavior of the metric or matter fields, and which is not confined to one specific metric configuration. As a result, we find that for a wide class of spacetime horizons there exists an emission of particles out of the horizon. As expected, the energy distribution of the radiating particles turns out to be thermal.
Deformation of contour and Hawking temperature
Chikun Ding; Jiliang Jing
2010-01-19T23:59:59.000Z
It was found that, in an isotropic coordinate system, the tunneling approach brings a factor of 1/2 for the Hawking temperature of a Schwarzschild black hole. In this paper, we address this kind of problem by studying the relation between the Hawking temperature and the deformation of integral contour for the scalar and Dirac particles tunneling. We find that correct Hawking temperature can be obtained exactly as long as the integral contour deformed corresponding to the radial coordinate transform if the transformation is a non-regular or zero function at the event horizon.
Hawking radiation on a falling lattice
Ted Jacobson; David Mattingly
2000-01-12T23:59:59.000Z
Scalar field theory on a lattice falling freely into a 1+1 dimensional black hole is studied using both WKB and numerical approaches. The outgoing modes are shown to arise from incoming modes by a process analogous to a Bloch oscillation, with an admixture of negative frequency modes corresponding to the Hawking radiation. Numerical calculations show that the Hawking effect is reproduced to within 0.5% on a lattice whose proper spacing where the wavepacket turns around at the horizon is $\\sim0.08$ in units where the surface gravity is 1.
The Hawking-Unruh phenomenon on graphene
Alfredo Iorio; Gaetano Lambiase
2012-09-03T23:59:59.000Z
We find that, for a very specific shape of a monolayer graphene sample, a general relativistic-like description of a back-ground spacetime for graphene's conductivity electrons is very natural. The corresponding electronic local density of states is of finite temperature. This is a Hawking-Unruh effect that we propose to detect through an experiment with a Scanning Tunneling Microscope.
Time dependence of Hawking radiation entropy
Page, Don N., E-mail: profdonpage@gmail.com [Department of Physics, 4-181 CCIS, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)
2013-09-01T23:59:59.000Z
If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4?M{sub 0}{sup 2}, or about 7.509M{sub 0}{sup 2} ? 6.268 × 10{sup 76}(M{sub 0}/M{sub s}un){sup 2}, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the black hole. Results are also given for black holes in initially impure states. If the black hole starts in a maximally mixed state, the von Neumann entropy of the Hawking radiation increases from zero up to a maximum of about 119.51% of the original BH entropy, or about 15.018M{sub 0}{sup 2} ? 1.254 × 10{sup 77}(M{sub 0}/M{sub s}un){sup 2}, and then decreases back down to 4?M{sub 0}{sup 2} = 1.049 × 10{sup 77}(M{sub 0}/M{sub s}un){sup 2}.
Generalized Hawking-Page Phase Transition
Parthasarathi Majumdar
2007-01-01T23:59:59.000Z
The issue of radiant spherical black holes being in stable thermal equilibrium with their radiation bath is reconsidered. Using a simple equilibrium statistical mechanical analysis incorporating Gaussian thermal fluctuations in a canonical ensemble of isolated horizons, the heat capacity is shown to diverge at a critical value of the classical mass of the isolated horizon, given (in Planckian units) by the {\\it microcanonical} entropy calculated using Loop Quantum Gravity. The analysis reproduces the Hawking-Page phase transition discerned for anti-de Sitter black holes and generalizes it in the sense that nowhere is any classical metric made use of.
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Renyi entropies of a black hole from Hawking radiation
A. Bialas; W. Czyz
2008-01-30T23:59:59.000Z
Renyi entropies of a black hole are evaluated by counting the states of the Hawking radiation which fills a thin shell surrounding the horizon. The width of the shell is determined from its energy content and the corresponding mass defect. The Bekenstein-Hawking formula for the entropy of the black hole is correctly reproduced.
Krein Quantization Approach to Hawking Radiation
H. Pejhan; S. Rahbardehghan
2015-01-07T23:59:59.000Z
A new version of canonical quantization method, in which the Fock space is built over a so-called Krein space, is considered in this paper. In this construction, interestingly, the Fock vacuum is unique. It is actually independent of Bogolubov transformations. Furthermore, no infinite term appears in the calculation of expectation values of the energy-momentum tensor, and in particular, corresponding value to the free field part of the theory on the vacuum state vanishes. Through the method, even in situations where the conventional approach fails, such as the de Sitter minimally coupled massless scalar field and massless spin-2 field, covariant quantization is accessible. Krein construction also has an interesting link to the vacuum energy issue in curved space-time. In this regard, however it seems that, a serious challenge threatens the theory; the risk of destroying black hole thermodynamics and Hawking radiation. In this paper, by proposing a model to simulate schwarzschild black holes, it is debated that Krein construction does not destroy black holes thermodynamics. More precisely, by applying the accelerated-mirror results to a black hole, it is shown that the hole produces black-body radiation which its temperature exactly coincides with the result obtained by Hawking for black hole radiation.
Quantum Black Hole Model and Hawking's Radiation
V. A. Berezin
1996-02-12T23:59:59.000Z
The black hole model with a self-gravitating charged spherical symmetric dust thin shell as a source is considered. The Schroedinger-type equation for such a model is derived. This equation appeared to be a finite differences equation. A theory of such an equation is developed and general solution is found and investigated in details. The discrete spectrum of the bound state energy levels is obtained. All the eigenvalues appeared to be infinitely degenerate. The ground state wave functions are evaluated explicitly. The quantum black hole states are selected and investigated. It is shown that the obtained black hole mass spectrum is compatible with the existence of Hawking's radiation in the limit of low temperatures both for large and nearly extreme Reissner-Nordstrom black holes. The above mentioned infinite degeneracy of the mass (energy) eigenvalues may appeared helpful in resolving the well known information paradox in the black hole physics.
The self-screening Hawking atmosphere
G. 't Hooft
1997-08-06T23:59:59.000Z
A model is proposed in which the Hawking particles emitted by a black hole are treated as an envelope of matter that obeys an equation of state, and acts as a source in Einstein's equations. This is a crude but interesting way to accommodate for the back reaction. For large black holes, the solution can be given analytically, if the equation of state is $p=\\kappa\\rho$, with $0<\\kappa<1$. The solution exhibits a singularity at the origin. If we assume $N$ free particle types, we can use a Hartree-Fock procedure to compute the contribution of one such field to the entropy, and the result scales as expected as $1/N$. A slight mismatch is found that could be attributed to quantum corrections to Einstein's equations, but can also be made to disappear when $\\k$ is set equal to one. The case $\\kappa=1$ is further analysed.
Hawking Radiation as Tunneling: the D-dimensional rotating case
M. Nadalini; L. Vanzo; S. Zerbini
2005-11-24T23:59:59.000Z
The tunneling method for the Hawking radiation is revisited and applied to the $D$ dimensional rotating case. Emphasis is given to covariance of results. Certain ambiguities afflicting the procedure are resolved.
Rotating embedded black holes: Entropy and Hawking's radiation
Ng Ibohal
2004-12-27T23:59:59.000Z
In this paper we derive a class of rotating embedded black holes. Then we study Hawking's radiation effects on these embedded black holes. The surface gravity, entropy and angular velocity are given for each of these black holes.
Hawking-Page transition in holographic massive gravity
Adams, Allan
We study the Hawking-Page transition in a holographic model of field theories with momentum dissipation. We find that the deconfinement temperature strictly decreases as momentum dissipation is increased. For sufficiently ...
Hawking Radiation as Tunnelling in Static Black Holes
Wenbiao Liu
2005-12-16T23:59:59.000Z
Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. The conservation of energy implies the effect of self-gravitation. For a static black hole, a generalized Painleve coordinate system is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is consistent with the underlying unitary theory.
Hawking Radiation as Tunnelling in Static Black Holes
Liu, W
2005-01-01T23:59:59.000Z
Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. The conservation of energy implies the effect of self-gravitation. For a static black hole, a generalized Painleve coordinate system is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is consistent with the underlying unitary theory.
Zitterbewegung and its significance for the Hawking radiation
Zhi-Yong Wang; Cai-Dong Xiong; Qi Qiu
2011-08-02T23:59:59.000Z
The Hawking radiation can be viewed from very different perspectives, not all of which can be proved to be rigorously equivalent to one another. On the other hand, an old interest in the zitterbewegung (ZB) of the Dirac electron has recently been rekindled by the investigations on spintronics and graphene, etc. In this letter, we show that, if particles emitted by black holes are electrons or positrons, one can also regard the Hawking radiation as a ZB process.
Hawking-Hayward quasi-local energy under conformal transformations
Angus Prain; Vincenzo Vitagliano; Valerio Faraoni; Marianne Lapierre-Léonard
2015-01-13T23:59:59.000Z
We derive a formula describing the transformation of the Hawking-Hayward quasi-local energy under a conformal rescaling of the spacetime metric. A known formula for the transformation of the Misner-Sharp-Hernandez mass is recovered as a special case.
Hawking-Page transition in holographic massive gravity
Allan Adams; Daniel A. Roberts; Omid Saremi
2015-02-03T23:59:59.000Z
We study the Hawking-Page transition in a holographic model of field theories with momentum dissipation. We find that the deconfinement temperature strictly decreases as momentum dissipation is increased. For sufficiently strong momentum dissipation, the critical temperature goes to zero, indicating a zero-temperature deconfinement transition in the dual field theory.
Note on Hawking-Unruh effects in graphene
Pisin Chen; H. C. Rosu
2012-11-16T23:59:59.000Z
Beltrami-shaped graphene sheets have been recently proposed as analogs of curved spacetimes with Hawking-Unruh effects detected through typical condensed matter measurements involving scanning tunneling microscopes and spectroscopy. However, such deformed sheets, if ever fabricated, will contain large strain-induced pseudomagnetic fields with important guiding effects on the motion of the electrons in the conduction band. Besides, possible surface polariton and plasmon modes are known to be important players in the radiative heat transfer which takes place in the natural near-field nanoscale experimental conditions. Therefore, we suggest here that the latter class of experiments could shed light on phenomena related to the black hole membrane paradigm instead
Interaction of Hawking radiation and a static electric charge
Luis C. B. Crispino; Atsushi Higuchi; George E. A. Matsas
1998-04-24T23:59:59.000Z
We investigate whether the equality found for the response of static scalar sources interacting (i) with {\\em Hawking radiation in Schwarzschild spacetime} and (ii) with the Fulling-Davies-Unruh thermal bath in the Rindler wedge is maintained in the case of electric charges. We find a finite result in the Schwarzschild case, which is computed exactly, in contrast with the divergent result associated with the infrared catastrophe in the Rindler case, i.e. in the case of uniformly accelerated charges in Minkowski spacetime. Thus, the equality found for scalar sources does not hold for electric charges.
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Mitigation planning for raptors during mining
Platt, S.W. [Wyoming Dept. of Environmental Quality/Land Quality Division, Lander, WY (United States); Hargis, N.E. [Bridger Coal Co., Rock Springs, WY (United States)
1990-12-31T23:59:59.000Z
Birds of prey and their eggs, young and nests are protected by state and federal laws and regulations. Surface mining operators may experience conflicts with raptors when expanding into nesting areas or when raptors are attracted into mining areas. State and federal permits are required for disturbance or manipulation of birds of prey. Mitigation planning for raptors begins before mining and continues through mining. As conflict situations changes, so must the mitigation plan. Before each nesting season the mining schedule should be compared to areas of known raptor nesting activity. If overlap occurs, nest protection measures may be needed. Areas of potential conflict should be patrolled regularly to identify the presence of a raptor pair and nest starts. Should a raptor nest be built and eggs laid, a change in the mining schedule or an egg or brood manipulation may resolve the conflict. Bridger Coal Company has successfully mitigated conflicts with 3 raptor species. A ferruginous hawk (Buteo regalis) nest with brood was successfully relocated across a pit. Red-tailed hawk (B. jamaicensis) egg clutches were removed from 2 highwall nests and transported in a portable incubator to a commercial raptor propagator where they were hatched, fed and conspecifically imprinted until achieving self-thermoregulation. All chicks were returned to the mine and successfully placed into foster nests. A metal artificial nest ledge for a prairie falcon (Falco mexicanus) was constructed in a cliff and a traditional nesting ledge rendered inaccessible. The falcon pair successfully nested in the artificial ledge.
Effective Action and Hawking Flux from Covariant Perturbation Theory
D. Hofmann; W. Kummer
2004-08-26T23:59:59.000Z
The computation of the radiation flux related to the Hawking temperature of a Schwarzschild Black Hole or another geometric background is still well-known to be fraught with a number of delicate problems. In spherical reduction, as shown by one of the present authors (W. K.) with D.V. Vassilevich, the correct black body radiation follows when two ``basic components'' (conformal anomaly and a ``dilaton'' anomaly) are used as input in the integrated energy-momentum conservation equation. The main new element in the present work is the use of a quite different method, the covariant perturbation theory of Barvinsky and Vilkovisky, to establish directly the full effective action which determines these basic components. In the derivation of W. K. and D.V. Vassilevich the computation of the dilaton anomaly implied one potentially doubtful intermediate step which can be avoided here. Moreover, the present approach also is sensitive to IR (renormalisation) effects. We realize that the effective action naturally leads to expectation values in the Boulware vacuum which, making use of the conservation equation, suffice for the computation of the Hawking flux in other quantum states, in particular for the relevant Unruh state. Thus, a rather comprehensive discussion of the effects of (UV and IR) renormalisation upon radiation flux and energy density is possible.
Hawking radiation in the presence of high-momentum dissipation
Scott Robertson; Renaud Parentani
2015-06-07T23:59:59.000Z
We study the Hawking radiation in field theories which break Lorentz invariance via dissipative effects above a certain energy scale. We assume that the additional degrees of freedom which cause dissipation are Gaussian and freely falling. The asymptotic spectrum and the correlations are extracted from the anticommutator of the radiation field. The singular behavior of the Green function found for relativistic fields as one point crosses the horizon is completely suppressed by dissipation. Yet, when the dissipative frequency scale is much larger than the surface gravity of the black hole, we show that the asymptotic observables acquire their standard (relativistic) vacuum expectation values. We explicitly compute the effects of dissipation on the spectrum and on the nonseparable character of the correlations when varying the dissipative scale, the extension of the near-horizon geometry, and the temperature of the environment.
One Hair Postulate for Hawking Radiation as Tunneling Process
H. Dong; Qing-yu Cai; X. F. Liu; C. P. Sun
2009-07-13T23:59:59.000Z
For Hawking radiation, treated as a tunneling process, the no-hair theorem of black hole together with the law of energy conservation is utilized to postulate that the tunneling rate only depends on the external qualities (e.g., the mass for the Schwarzschild black hole) and the energy of the radiated particle. This postulate is justified by the WKB approximation for calculating the tunneling probability. Based on this postulate, a general formula for the tunneling probability is derived without referring to the concrete form of black hole metric. This formula implies an intrinsic correlation between the successive processes of the black hole radiation of two or more particles. It also suggests a kind of entropy conservation and thus resolves the puzzle of black hole information loss in some sense.
New Coordinates for BTZ Black Hole and Hawking Radiation via Tunnelling
Wenbiao Liu
2005-12-16T23:59:59.000Z
Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. For the stationary axisymmetric BTZ black hole, a generalized Painleve coordinate system (Painleve-BTZ coordinates) is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is obtained which is not precise thermal spectrum. The result is consistent with the underlying unitary theory. Moreover, Bekenstein-Hawking entropy of BTZ black hole is not necessarily corrected when we choose appropriate coordinate system to study the tunnelling effect.
Dead poets' society New England, the 1950s. Todd Anderson (Ethan Hawke), a lonely and painfully
Schenato, Luca
Dead poets' society New England, the 1950s. Todd Anderson (Ethan Hawke), a lonely and painfully shy in it. After seeing that Mr. Keating listed "Dead Poets Society" as one of his activities at the school
Gambling tourism and image marketing: an example from Black Hawk, Colorado
Yang, Xiaobing
1998-01-01T23:59:59.000Z
GAMBLING TOURISM AND IMAGE MARKETING: AN EXAMPLE FROM BLACK HAWK, COLORADO A Thesis by XIAOBING YANG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1998 Major Subject: Recreation, Park and Tourism Sciences GAMBLING TOURISM AND IMAGE MARKETING: AN EXAMPLE FROM BLACK HAWK, COLORADO A Thesis by XIAOBING YANG Submitted to the Office of Graduate Studies of Texas ASSAM University...
The Hawking effect in dielectric media and the Hopfield model
F. Belgiorno; S. L. Cacciatori; F. Dalla Piazza
2014-11-28T23:59:59.000Z
We consider the so-called Hopfield model for the electromagnetic field in a dielectric dispersive medium in a framework in which one allows a space-time dependence of microscopic parameters, aimed to a phenomenological description of a space-time varying dielectric perturbation induced by means of the Kerr effect. We discuss the analogue Hawking effect, by first analyzing the geometrical optics for the Hopfield model, and then by introducing a simplified model which has the bonus to avoid many difficulties which are involved in the full Hopfield model, still keeping the same dispersion relation. Amplitude calculations are indicated, and generalized Manley-Rowe identities are derived in a quantum scattering theory framework. Our main result is an analytical calculation of the spontaneous thermal emission in the single-branch case, which is provided non perturbatively for the first time in the framework of dielectric black holes. An universal mechanism for thermality between optical black holes and acoustic black holes is also pointed out.
Antonin Coutant
2014-05-14T23:59:59.000Z
In this thesis, we study several features of Hawking radiation in the presence of ultraviolet Lorentz violations. These violations are implemented by a modified dispersion relation that becomes nonlinear at short wavelengths. The motivations of this work arise on the one hand from the developing field of analog gravity, where we aim at measuring the Hawking effect in fluid flows that mimic black hole space-times, and on the other hand from the possibility that quantum gravity effects might be approximately modeled by a modified dispersion relation. We develop several studies on various aspects of the problem. First we obtain precise characterizations about the deviations from the Hawking result of black hole radiation, which are induced by dispersion. Second, we study the emergence, both in white hole flows or for massive fields, of a macroscopic standing wave, spontaneously produced from the Hawking effect, and known as `undulation'. Third, we describe in detail an instability named black hole laser, which arises in the presence of two horizons, where Hawking radiation is self-amplified and induces an exponentially growing in time emitted flux.
Hawking radiation from Trojan states in muonic Hydrogen in strong laser field
Matt Kalinski
2005-01-28T23:59:59.000Z
We show that the Unruh-Davies effect is measurable from Trojan wavepackets in muonic Hydrogen as the acceleration on the first muonic Bohr orbit reaches 10^25 of the earth acceleration. It is the biggest acceleration achievable in the laboratory environment which have been ever predicted for the cyclotronic configuration. We calculate the ratio between the power of Larmor radiation and the power of Hawking radiation. The Hawking radiation is measurable even for quantum numbers of the muon due to suppression of spontaneous emission in Trojan Hydrogen.
Measuring Hawking Radiation of a Kerr-Newman Black Hole in a Superconducting Transmission Line
X. G. Lan; D. Y. Chen; L. F. Wei
2014-03-21T23:59:59.000Z
Applying a dimensional reduction technique and a coordinates transformation approach, we deduce the Kerr-Newman space-time into a Painlev\\'{e}-like form, and obtain its corresponding event horizon and the Hawking radiation temperature. We find that, the event horizon of a Kerr-Newman black hole can be simulated in a superconducting transmission line. Moreover, by running some numerical simulation, we confirm that the Hawking radiation of a Kerr-Newman Black Hole can be experimentally measured in a superconducting transmission line.
Measuring the entanglement of analogue Hawking radiation by the density-density correlation function
Steinhauer, Jeff
2015-01-01T23:59:59.000Z
We theoretically study the entanglement of Hawking radiation emitted by an analogue black hole. We find that this entanglement can be measured by the experimentally accessible density-density correlation function, which only requires standard imaging techniques. It is seen that the high energy tail of the distribution of Hawking radiation should be entangled, whereas the low energy part is not. This confirms a previous numerical study. The full Peres-Horodecki criterion is considered, but a significant simplification is found in the stationary, homogeneous case. Our method applies to systems which are sufficiently cold that the thermal phonons can be neglected.
Hawking radiation for a scalar field conformally coupled to an AdS black hole
P. Valtancoli
2015-02-05T23:59:59.000Z
The decomposition in normal modes of a scalar field conformally coupled to an AdS black hole leads to a Heun equation with simple coefficients thanks to conformal invariance. By applying the Damour-Ruffini method we can relate the critical exponent of the radial part at the horizon surface to the Hawking radiation of scalar particles.
Thoughts on entropic gravity in the Parikh-Wilczek tunneling model of Hawking radiation
Wen-Yu Wen
2014-05-28T23:59:59.000Z
In this letter, we use the Parikh-Wilczek tunneling model of Hawking radiation to illustrate that a reformulation of Verlinde's entropic gravity is needed to derive the Newton's law for a temperature-varying screen, demanded by the conservation of energy. Furthermore, the entropy stored in the holographic screen is shown to be additive and its temperature dependence can be obtained.
Hawking temperature for various kinds of black holes from Heisenberg uncertainty principle
Fabio Scardigli
2006-07-04T23:59:59.000Z
Hawking temperature is computed for a large class of black holes (with spherical, toroidal and hyperboloidal topologies) using only laws of classical physics plus the "classical" Heisenberg Uncertainty Principle. This principle is shown to be fully sufficient to get the result, and there is no need to this scope of a Generalized Uncertainty Principle.
A microwave metamaterial with integrated power harvesting functionality Allen M. Hawkes,a)
Cummer, Steven A.
A microwave metamaterial with integrated power harvesting functionality Allen M. Hawkes power harvesting, the focus of this work. Power harvesting devices convert one type of energy to another, typically converting to a direct current (DC) signal. Many types of energy can be harvested, from acoustic
or repair services at wind turbines. The WRRS database is a collection of fatality data collected without. Unfortunately, Kerlinger and Curry only presented mortality estimates for golden eagles and red-tailed hawks-tailed hawks and 18 (60%)) of the golden eagles per year among the 3,412 turbines. Compared to our mortality
Probing the thermal character of analogue Hawking radiation for shallow water waves?
Florent Michel; Renaud Parentani
2014-09-15T23:59:59.000Z
We study and numerically compute the scattering coefficients of shallow water waves blocked by a stationary counterflow. When the flow is transcritical, the coefficients closely follow Hawking's prediction according to which black holes should emit a thermal spectrum. We study how the spectrum deviates from thermality when reducing the maximal flow velocity, with a particular attention to subcritical flows since these have been recently used to test Hawking's prediction. For such flows, we show that the emission spectrum is strongly suppressed, and that its Planckian character is completely lost. For low frequencies, we also show that the scattering coefficients are dominated by elastic hydrodynamical channels. Our numerical results reproduce rather well the observations made by S. Weinfurtner {\\it et al.} in the Vancouver experiment. Nevertheless, we propose a new interpretation of what has been observed, as well as new experimental tests.
Zhang Baocheng [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Cai Qingyu, E-mail: qycai@wipm.ac.cn [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Zhan Mingsheng [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China); You Li [Department of Physics, Tsinghua University, Beijing 100084 (China)
2011-02-15T23:59:59.000Z
Research Highlights: > Information is found to be encoded and carried away by Hawking radiations. > Entropy is conserved in Hawking radiation. > We thus conclude no information is lost. > The dynamics of black hole may be unitary. - Abstract: We revisit in detail the paradox of black hole information loss due to Hawking radiation as tunneling. We compute the amount of information encoded in correlations among Hawking radiations for a variety of black holes, including the Schwarzchild black hole, the Reissner-Nordstroem black hole, the Kerr black hole, and the Kerr-Newman black hole. The special case of tunneling through a quantum horizon is also considered. Within a phenomenological treatment based on the accepted emission probability spectrum from a black hole, we find that information is leaked out hidden in the correlations of Hawking radiation. The recovery of this previously unaccounted for information helps to conserve the total entropy of a system composed of a black hole plus its radiations. We thus conclude, irrespective of the microscopic picture for black hole collapsing, the associated radiation process: Hawking radiation as tunneling, is consistent with unitarity as required by quantum mechanics.
On the Hawking Turok solution to the Open Universe wave function
W. Unruh
1998-03-14T23:59:59.000Z
Hawking and Turok have recently published a solution to the WKB "wave-function for the universe" which they claim leads in a natural way to an open universe as the end point of the evolution for a universe dominated by a scalar field. They furthermore argue that their solution a preferred solution under the rules of the game. This paper will, I hope, clarify their solution and the limits of validity of their argument.
Luis C. Barbado
2015-01-12T23:59:59.000Z
We study the perception of the radiation phenomena of Hawking radiation and Unruh effect by using two main tools: the Unruh-DeWitt detectors and the effective temperature function (ETF), this last tool based on Bogoliubov transformations. Using the Unruh-DeWitt detectors we find an adiabatic expansion of the detection properties along linear trajectories with slowly varying acceleration in Minkowski, which allows us to calculate the spectrum detected, finding the thermal spectrum as the zeroth order contribution. Using the ETF we study the perception of Hawking radiation by observers following radial trajectories outside a Schwarzschild black hole. One of the most important results is that, in general, free-falling observers crossing the event horizon do detect some radiation, even when the field is in the Unruh vacuum state, due to a Doppler blue-shift that diverges at the horizon. We give a general expression for the ETF, which has a clear interpretation in terms of well-known physical phenomena. We discuss which contribution to the perception comes from the radiation emitted by the black hole, and which contribution is due to the Unruh effect caused by the movement of the observer. We conclude that the Unruh effect is not only due to the observer's proper acceleration and cannot even be defined locally, but is due to the observer's acceleration with respect to the asymptotic region. We apply the ETF to the analysis of different physical situations, in particular to a possible buoyancy scenario near the horizon due to Hawking radiation pressure. Finally, we propose a non-stationary vacuum state, which we call pulsating vacuum, for the radiation field outside a stellar object hovering closely to form an event horizon. In this vacuum state, we get nearly Hawking radiation emitted by the object, while avoiding the known problems of the information paradox and the trans-planckian problem.
Hawking fluxes, fermionic currents, W{sub 1+{infinity}} algebra, and anomalies
Bonora, L. [International School for Advanced Studies (SISSA/ISAS) Via Beirut 2-4, 34014 Trieste (Italy) and INFN, Sezione di Trieste (Italy); Cvitan, M. [International School for Advanced Studies (SISSA/ISAS) Via Beirut 2-4, 34014 Trieste (Italy) and INFN, Sezione di Trieste (Italy); Theoretical Physics Department, Faculty of Science, University of Zagreb Bijenicka cesta 32, HR-10002 Zagreb (Croatia); Pallua, S.; Smolic, I. [Theoretical Physics Department, Faculty of Science, University of Zagreb Bijenicka cesta 32, HR-10002 Zagreb (Croatia)
2009-10-15T23:59:59.000Z
We complete the analysis carried out in previous papers by studying the Hawking radiation for a Kerr black hole carried to infinity by fermionic currents of any spin. We find agreement with the thermal spectrum of the Hawking radiation for fermionic degrees of freedom. We start by showing that the near-horizon physics for a Kerr black hole is approximated by an effective two-dimensional field theory of fermionic fields. Then, starting from two-dimensional currents of any spin that form a W{sub 1+{infinity}} algebra, we construct an infinite set of covariant currents, each of which carries the corresponding moment of the Hawking radiation. All together they agree with the thermal spectrum of the latter. We show that the predictive power of this method is based not on the anomalies of the higher-spin currents (which are trivial) but on the underlying W{sub 1+{infinity}} structure. Our results point toward the existence in the near-horizon geometry of a symmetry larger than the Virasoro algebra, which very likely takes the form of a W{sub {infinity}} algebra.
Laura Mersini-Houghton; Harald P. Pfeiffer
2014-09-05T23:59:59.000Z
A star collapsing gravitationally into a black hole emits a flux of radiation, knowns as Hawking radiation. When the initial state of a quantum field on the background of the star, is placed in the Unruh vacuum in the far past, then Hawking radiation corresponds to a flux of positive energy radiation travelling outwards to future infinity. The evaporation of the collapsing star can be equivalently described as a negative energy flux of radiation travelling radially inwards towards the center of the star. Here, we are interested in the evolution of the star during its collapse. Thus we include the backreaction of the negative energy Hawking flux in the interior geometry of the collapsing star and solve the full 4-dimensional Einstein and hydrodynamical equations numerically. We find that Hawking radiation emitted just before the star passes through its Schwarzschild radius slows down the collapse of the star and substantially reduces its mass thus the star bounces before reaching the horizon. The area radius starts increasing after the bounce. Beyond this point our program breaks down due to shell crossing. We find that the star stops collapsing at a finite radius larger than its horizon, turns around and its core explodes. This study provides a more realistic investigation of the backreaction of Hawking radiation on the collapsing star, that was first presented in [1].
On arithmetic detection of grey pulses with application to Hawking radiation
H. C. Rosu; M. Planat
2002-08-04T23:59:59.000Z
Micron-sized black holes do not necessarily have a constant horizon temperature distribution. The black hole remote-sensing problem means to find out the `surface' temperature distribution of a small black hole from the spectral measurement of its (Hawking) grey pulse. This problem has been previously considered by Rosu, who used Chen's modified Moebius inverse transform. Here, we hint on a Ramanujan generalization of Chen's modified Moebius inverse transform that may be considered as a special wavelet processing of the remote-sensed grey signal coming from a black hole or any other distant grey source
Probing Hawking and Unruh effects and quantum field theory in curved space by geometric invariants
Antonio Capolupo; Giuseppe Vitiello
2013-11-12T23:59:59.000Z
The presence of noncyclic geometric invariant is revealed in all the phenomena where particle generation from vacuum or vacuum condensates appear. Aharonov--Anandan invariants then can help to study such systems and can represent a new tool to be used in order to provide laboratory evidence of phenomena particulary hard to be detected, such as Hawking and Unruh effects and some features of quantum field theory in curved space simulated by some graphene morphologies. It is finally suggested that a very precise quantum thermometer can be built by exploiting geometric invariants properties.
J. Naji
2014-04-18T23:59:59.000Z
In this paper, we considered new solutions for four-dimensional asymptotically AdS black holes with scalar hair and discuss about Hawking temperature in the context of dark energy by using the tunneling method. We obtain modification of the Hawking temperature due to presence of the dark energy.
Red and blue tilted tensor spectrum from Gibbons-Hawking temperature
Subhendra Mohanty; Akhilesh Nautiyal
2015-01-09T23:59:59.000Z
The scale invariant scalar and tensor perturbations, which are predicted from inflation, are eigenmodes in the conformal coordinates. The 'out' observer in the de Sitter space observes a thermal spectrum with a Gibbons-Hawking temperature $H/2\\pi$ of these 'Bunch-Davies' particles. The tensor power spectrum observed in experiments can have an imprint of the Gibbons-Hawking thermal distribution due to the mode mixing between 'in' state conformal coordinates and the coordinate frame of the observer. We find that the the Bunch-Davies modes appear as thermal modes to the asymptotic Minkowski observer in the future and the power spectrum of the gravitational waves is blue-tilted with a spectral index $n_T \\sim 1$ even in the standard slow-roll inflation. On the other hand if the coordinate frame of the observer is taken to be static coordinates, the tensor spectrum is red-tilted with $n_T\\sim -1$. A likelihood analysis shows and find the best fit values of the slow-roll parameters for both cases. We find that the blue-tilted tensor gives a better fit and reconciles the PLANCK upper bound on the tensor-to-scalar ratio, $r <0.11$ with BICEP2 measurement of $r=0.2$. This supports the idea of particle production due to the mode mixing between the initial Bunch-Davies vacuum modes and the asymptotic Minkowski vacuum of the post-inflation universe.
On the construction of Hartle-Hawking-Israel states across a static bifurcate Killing horizon
Ko Sanders
2015-01-29T23:59:59.000Z
We consider a linear scalar quantum field propagating in a space-time with a static bifurcate Killing horizon and a wedge reflection. We prove the existence of a Hadamard state which is pure, quasi-free, invariant under the Killing flow and which restricts to a double KMS state at the inverse Hawking temperature on the union of the exterior wedge regions. The existence of such a state was first conjectured by Hartle and Hawking (1976) and Israel (1976) for stationary black hole space times. Our result complements a uniqueness result of Kay and Wald (1991), who considered a general bifurcate Killing horizon and proved that a certain (large) subalgebra of the free field algebra admits at most one Hadamard state which is invariant under the Killing flow. In the presence of a wedge reflection this state reduces to a pure, quasi-free KMS state on the smaller subalgebra associated to one of the exterior wedge regions. Our result establishes the existence of such a state on the full algebra in the static case. Our proof follows the arguments of Sewell (1982) and Jacobson (1994), exploiting a Wick rotation in the Killing time coordinate to construct a corresponding Euclidean theory. Because the Killing time coordinate is ill-defined on the bifurcation surface we systematically replace it by a Gaussian normal coordinate. A crucial part of our proof is to establish that the Euclidean ground state satisfies the necessary analogs of analyticity and reflection positivity with respect to this coordinate.
Hawking Radiation of a Quantum Black Hole in an Inflationary Universe
Wung-Hong Huang
2004-09-07T23:59:59.000Z
The quantum stress-energy tensor of a massless scalar field propagating in the two-dimensional Vaidya-de Sitter metric, which describes a classical model spacetime for a dynamical evaporating black hole in an inflationary universe, is analyzed. We present a possible way to obtain the Hawking radiation terms for the model with arbitrary functions of mass. It is used to see how the expansion of universe will affect the dynamical process of black hole evaporation. The results show that the cosmological inflation has an inclination to depress the black hole evaporation. However, if the cosmological constant is sufficiently large then the back-reaction effect has the inclination to increase the black hole evaporation. We also present a simple method to show that it will always produce a divergent flux of outgoing radiation along the Cauchy horizon where the curvature is a finite value. This means that the Hawking radiation will be very large in there and shall modify the classical spacetime drastically. Therefore the black hole evaporation cannot be discussed self-consistently on the classical Vaidya-type spacetime. Our method can also be applied to analyze the quantum stress-energy tensor in the more general Vaidya-type spacetimes.
Hawking radiation and the boomerang behavior of massive modes near a horizon
Jannes, G. [Universite de Nice Sophia Antipolis, Laboratoire J.-A. Dieudonne, UMR CNRS-UNS 6621, Parc Valrose, 06108 Nice Cedex 02 (France); Low Temperature Laboratory, Aalto University School of Science, PO Box 15100, 00076 Aalto (Finland); Maiessa, P.; Rousseaux, G. [Universite de Nice Sophia Antipolis, Laboratoire J.-A. Dieudonne, UMR CNRS-UNS 6621, Parc Valrose, 06108 Nice Cedex 02 (France); Philbin, T. G. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, Scotland (United Kingdom)
2011-05-15T23:59:59.000Z
We discuss the behavior of massive modes near a horizon based on a study of the dispersion relation and wave packet simulations of the Klein-Gordon equation. We point out an apparent paradox between two (in principle equivalent) pictures of black-hole evaporation through Hawking radiation. In the picture in which the evaporation is due to the emission of positive-energy modes, one immediately obtains a threshold for the emission of massive particles. In the picture in which the evaporation is due to the absorption of negative-energy modes, such a threshold apparently does not exist. We resolve this paradox by tracing the evolution of the positive-energy massive modes with an energy below the threshold. These are seen to be emitted and move away from the black-hole horizon, but they bounce back at a 'red horizon' and are reabsorbed by the black hole, thus compensating exactly for the difference between the two pictures. For astrophysical black holes, the consequences are curious but do not affect the terrestrial constraints on observing Hawking radiation. For analogue-gravity systems with massive modes, however, the consequences are crucial and rather surprising.
Barbado, Luis C
2015-01-01T23:59:59.000Z
We study the perception of the radiation phenomena of Hawking radiation and Unruh effect by using two main tools: the Unruh-DeWitt detectors and the effective temperature function (ETF), this last tool based on Bogoliubov transformations. Using the Unruh-DeWitt detectors we find an adiabatic expansion of the detection properties along linear trajectories with slowly varying acceleration in Minkowski, which allows us to calculate the spectrum detected, finding the thermal spectrum as the zeroth order contribution. Using the ETF we study the perception of Hawking radiation by observers following radial trajectories outside a Schwarzschild black hole. One of the most important results is that, in general, free-falling observers crossing the event horizon do detect some radiation, even when the field is in the Unruh vacuum state, due to a Doppler blue-shift that diverges at the horizon. We give a general expression for the ETF, which has a clear interpretation in terms of well-known physical phenomena. We discuss...
The Hawking Temperature in the context of Dark Energy for Reissner-Nordstrom and Kerr background
Goutam Manna; Debashis Gangopadhyay
2014-03-17T23:59:59.000Z
For emergent gravity metrics, presence of dark energy modifies the Hawking temperature. We show that for the spherically symmetric Reissner-Nordstrom (RN) background metric, the emergent metric can be mapped into a Robinson-Trautman blackhole. Allowed values of the dark energy density follow from rather general conditions. For some allowed value of the dark energy density this blackhole can have zero Hawking temperature i.e. the blackhole does not radiate. For a Kerr background along $\\theta=0$, the emergent blackhole metric satisfies Einstein's equations for large $r$ and always radiates. Our analysis is done in the context of emergent gravity metrics having $k-$essence scalar fields $\\phi$ with a Born-Infeld type lagrangian. In both cases the scalar field $\\phi(r,t)=\\phi_{1}(r)+\\phi_{2}(t)$ also satisfies the emergent gravity equations of motion for $r\\rightarrow\\infty$ and $\\theta=0$. \\keywords{dark energy, k-essence, Reissner-Nordstrom and Kerr blackholes} \\pacs{98.80.-k ;95.36.+x}
Hawking radiation as tunneling from charged black holes in 0A string theory
Hongbin Kim
2011-07-22T23:59:59.000Z
There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitive picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for achieving this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.
Hawking temperature for a global monopole metric in the context of k- essence and emergent gravity
Debashis Gangopadhyay; Goutam Manna
2011-08-04T23:59:59.000Z
The Hawking temperature for the Barriola-Vilenkin global monopole metric is shown to be $T_{\\mathrm BV}= {\\hbar (1-\\alpha) ^{2}\\over8\\pi GM k_{\\mathrm B}}$, where $\\alpha$ is the global monopole charge,$M$ the mass of the black hole, $k_{\\mathrm B}$ is the Boltzmann constant and speed of light $c=1$. We then show that a similar metric can also be obtained for certain $k-$ essence field configurations in an emergent gravity situation. Therefore, in the context of Belgiorno {\\it et al's} recent demonstration of spontaneous emission of photons in a gravitational analogue experiment, any future observation of $T_{\\mathrm BV}$ need not necessarily imply the existence of global monopoles. An alternative implication might as well be a very indirect signature of dark energy in an emergent gravity scenario. This should lead to effects that may be detectable in refined and modified versions of Belgiorno {\\it et al's} experiment.
Alfredo Iorio; Gaetano Lambiase
2014-12-15T23:59:59.000Z
The solutions of many issues, of the ongoing efforts to make deformed graphene a tabletop quantum field theory in curved spacetimes, are presented. A detailed explanation of the special features of curved spacetimes, originating from embedding portions of the Lobachevsky plane into $\\mathbf{R}^3$, is given, and the special role of coordinates for the physical realizations in graphene, is explicitly shown, in general, and for various examples. The Rindler spacetime is reobtained, with new important differences with respect to earlier results. The de Sitter spacetime naturally emerges, for the first time, paving the way to future applications in cosmology. The role of the BTZ black hole is also briefly addressed. The singular boundary of the pseudospheres, "Hilbert horizon", is seen to be closely related to event horizon of the Rindler, de Sitter, and BTZ kind. This gives new, and stronger, arguments for the Hawking phenomenon to take place. An important geometric parameter, $c$, overlooked in earlier work, takes here its place for physical applications, and it is shown to be related to graphene's lattice spacing, $\\ell$. It is shown that all surfaces of constant negative curvature, ${\\cal K} = -r^{-2}$, are unified, in the limit $c/r \\to 0$, where they are locally applicable to the Beltrami pseudosphere. This, and $c = \\ell$, allow us a) to have a phenomenological control on the reaching of the horizon; b) to use spacetimes different than Rindler for the Hawking phenomenon; c) to approach the generic surface of the family. An improved expression for the thermal LDOS is obtained. A non-thermal term for the total LDOS is found. It takes into account: a) the peculiarities of the graphene-based Rindler spacetime; b) the finiteness of a laboratory surface; c) the optimal use of the Minkowski quantum vacuum, through the choice of this Minkowski-static boundary.
Gibbons-Hawking Effect in the Sonic de Sitter Space-Time of an Expanding Bose-Einstein-Condensed Gas
Petr O. Fedichev; Uwe R. Fischer
2003-12-15T23:59:59.000Z
We propose an experimental scheme to observe the Gibbons-Hawking effect in the acoustic analog of a 1+1-dimensional de Sitter universe, produced in an expanding, cigar-shaped Bose-Einstein condensate. It is shown that a two-level system created at the center of the trap, an atomic quantum dot interacting with phonons, observes a thermal Bose distribution at the de Sitter temperature.
Hawking-Unruh Thermal Radiance as Relativistic Exponential Scaling of Quantum Noise
B. L. Hu
1996-06-26T23:59:59.000Z
The Hawking-Unruh effect of thermal radiance from a black hole or observed by an accelerated detector is usually viewed as a geometric effect related to the existence of an event horizon. Here we propose a new viewpoint, that the detection of thermal radiance in these systems is a local, kinematic effect arising from the vacuum being subjected to a relativistic exponential scale transformation. This kinematic effect alters the relative weight of quantum versus thermal fluctuations (noise) between the two vacua. This approach can treat conditions which the geometric approach cannot, such as systems which do not even have an event horizon. An example is the case of an observer whose acceleration is nonuniform or only asymptotically uniform. Since this approach is based on concepts and techniques of non-equilibrium statistical mechanics, it is more adept to dynamical problems, such as the dissipation, fluctuation, and entropy aspects of particle creation and phase transitions in black hole collapse and in the early universe.
Onset and decay of the 1+1 Hawking-Unruh effect: what the derivative-coupling detector saw
Benito A. Juárez-Aubry; Jorma Louko
2014-11-25T23:59:59.000Z
We study an Unruh-DeWitt particle detector that is coupled to the proper time derivative of a real scalar field in 1+1 spacetime dimensions. Working within first-order perturbation theory, we cast the transition probability into a regulator-free form, and we show that the transition rate remains well defined in the limit of sharp switching. The detector is insensitive to the infrared ambiguity when the field becomes massless, and we verify explicitly the regularity of the massless limit for a static detector in Minkowski half-space. We then consider a massless field for two scenarios of interest for the Hawking-Unruh effect: an inertial detector in Minkowski spacetime with an exponentially receding mirror, and an inertial detector in $(1+1)$-dimensional Schwarzschild spacetime, in the Hartle-Hawking-Israel and Unruh vacua. In the mirror spacetime the transition rate traces the onset of an energy flux from the mirror, with the expected Planckian late time asymptotics. In the Schwarzschild spacetime the transition rate of a detector that falls in from infinity gradually loses thermality, diverging near the singularity proportionally to $r^{-3/2}$.
Optimization in the Parikh-Wilczek tunneling model of Hawking radiation for Kerr-Newman Black Holes
Auttakit Chatrabhuti; Khem Upathambhakul
2014-03-17T23:59:59.000Z
In this short report, we investigate the mutual information hidden in the Parikh-Wilczek tunneling model of Hawking radiation for Kerr-Newman black holes. By assuming the radiation as an optimization process, we discuss its effect on time evolution of rotating (charged and uncharged) black holes. For uncharged rotating black holes evaporating under the maximum mutual information optimization, their scale invariant rotation parameter $a_*=a/M$ is almost constant at the early stage but rapidly increase at the very last stage of the evaluation process. The value of rotation parameter at the final state of evaporation depends on the initial condition of the black hole. We also found that the presence of electric charge can cause the black holes lose their angular momentum more rapidly than they lose mass. The charged-rotating black holes asymptotically approach a state which is described by $a_*= 0$ and $Q/M = 1$.
First Specimens of Buteo Albicaudatus and Chordeiles Minor in Uruguay
Juan Cuello Journal: Condor Volume: 68 Issue: 3 (May-June) Section: Short Communications Year: 1966 Pages: 301
I T E. o.. o , o . ,'-. ." . ! Aquarterly publication for educatorsandthe pul~lic-
Dunbar, Nelia W.
, where would you settle? Howabout a narrow ledge on the highwall of an active, surface coal mine in NewMexico--see back page New Mexico Bureau of Mines and Mineral Resources (NMBM&MR) EarthBriefs Miningis for the Birds?That is exactly where one persistent red-tailed hawk and her mate chose to roost at the Pittsburg & Midway(P&M)Coal
COLLOQUIUM - HAWKING AUDITORIUM
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWPSuccess Stories Siteandscience, and8Critical4CO2 CompressionCOLLOQUIUM
HAWK-I imaging of the X-ray luminous galaxy cluster XMMU J2235.3-2557: The red sequence at z=1.39
C. Lidman; P. Rosati; M. Tanaka; V. Strazzullo; R. Demarco; C. Mullis; N. Ageorges; M. Kissler-Patig; M. G. Petr-Gotzens; F. Selman
2008-08-20T23:59:59.000Z
We use HAWK-I, the recently-commissioned near-IR imager on Yepun (VLT-UT4), to obtain wide-field, high-resolution images of the X-ray luminous galaxy cluster XMMU J2235.3-2557 in the J and Ks bands, and we use these images to build a colour-magnitude diagram of cluster galaxies. Galaxies in the core of the cluster form a tight red sequence with a mean J-Ks colour of 1.9 (Vega system). The intrinsic scatter in the colour of galaxies that lie on the red sequence is similar to that measured for galaxies on the red sequence of the Coma cluster. The slope and location of the red sequence can be modelled by passively evolving the red sequence of the Coma cluster backwards in time. Using simple stellar population (SSP) models, we find that galaxies in the core of XMMU J2235.3-2557 are, even at z=1.39, already 3 Gyr old, corresponding to a formation redshift of z ~ 4. Outside the core, the intrinsic scatter and the fraction of galaxies actively forming stars increase substantially. Using SSP models, we find that most of these galaxies will join the red sequence within 1.5 Gyr. The contrast between galaxies in the cluster core and galaxies in the cluster outskirts indicates that the red sequence of XMMU J2235.3-2557 is being built from the dense cluster core outwards.
Controlled Hawking Process by Quantum Energy Teleportation
Masahiro Hotta
2010-02-03T23:59:59.000Z
In this paper, a new quantum mechanical method to extract energy from black holes with contracting horizons is proposed. The method is based on a gedanken experiment on quantum energy teleportation (QET), which has been recently proposed in quantum information theory. We consider this QET protocol for N massless fields in near-horizon regions of large-mass black holes with near-horizon geometry described by the Minkowski metric. For each field, a two-level spin is strongly coupled with the local quantum fluctuation outside the horizon during a short time period. After the measurement of N fields, N-bit information is obtained. During the measurement, positive-energy wave packets of the fields form and then fall into the black hole. The amount of excitation energy is independent of the measurement result. After absorption of the wave packets and increase of the black hole mass, a measurement-result-dependent local operation of the N fields is performed outside the horizon. Then, accompanying the extraction of positive energy from the quantum fluctuation by the operation, negative-energy wave packets of the fields form and then fall into the black hole, decreasing the black hole mass. This implies that a part of the absorbed positive energy emitted from the measurement devices is effectively retrieved from the black hole via the measurement results.
Women @ Energy: Carol Hawk | Department of Energy
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Women @ Energy: Carol Hawk | Department of Energy
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Supporting Postgraduate Research at Erika Hawkes, University Graduate School
Birmingham, University of
& professional development Oversees administrative processes for PGRs Guides University strategy Studentships Officer Rachel Patti UGS Data Officer Katharine D'Souza UGS Administrator Sophie Pumphrey UGS Projects Officer-Kim Loynes #12;With a little help from our friends... Colleges Careers Network
Raspberry and Lemon Polenta Cake Emily Hawkes -Communications & Marketing Services
Chapman, Robin
½ tsp baking powder ½ tsp vanilla bean extract Zest of 1 lemon 200g fresh or frozen raspberries FILLING least 70% cocoa) 240g Boiling water 225g Self raising flour ½ tsp. salt 1 tsp. bicarbonate of soda 330g and boiling water. Whisk until fully combined and smooth. Let this mixture cool to room temperature (approx. 4
Hawking Radiation of a Charged Black Hole in Quantum Gravity
Ichiro Oda
2015-03-18T23:59:59.000Z
We study black hole radiation of a Reissner-Nordstrom black hole with an electric charge in the framework of quantum gravity. Based on a canonical quantization for a spherically symmetric geometry, under physically plausible assumptions, we solve the Wheeler-De Witt equation in the regions not only between the outer apparent horizon and the spatial infinity but also between the spacetime singularity and the inner apparent horizon, and then show that the mass loss rate of an evaporating black hole due to thermal radiation agrees with the semiclassical result when we choose an integration constant properly by physical reasoning. Furthermore, we also solve the Wheeler-De Witt equation in the region between the inner Cauchy horizon and the outer apparent horizon, and show that the mass loss rate of an evaporating black hole has the same expression. The present study is the natural generalization of the case of a Schwarzschild black hole to that of a charged Reissner-Nordstrom black hole.
Hawking Radiation of a Charged Black Hole in Quantum Gravity
Oda, Ichiro
2015-01-01T23:59:59.000Z
We study black hole radiation of a Reissner-Nordstrom black hole with an electric charge in the framework of quantum gravity. Based on a canonical quantization for a spherically symmetric geometry, under physically plausible assumptions, we solve the Wheeler-De Witt equation in the regions not only between the outer apparent horizon and the spatial infinity but also between the spacetime singularity and the inner apparent horizon, and then show that the mass loss rate of an evaporating black hole due to thermal radiation agrees with the semiclassical result when we choose an integration constant properly by physical reasoning. Furthermore, we also solve the Wheeler-De Witt equation in the region between the inner Cauchy horizon and the outer apparent horizon, and show that the mass loss rate of an evaporating black hole has the same expression. The present study is the natural generalization of the case of a Schwarzschild black hole to that of a charged Reissner-Nordstrom black hole.
MHK Technologies/RED HAWK | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer Plant Jump to:LandownersLuther, Oklahoma:EnergyECO Auger < MHK TechnologiesProteusRED
A faux hawk fullerene with PCBM-like properties
San, Long K.; Bukovsky, Eric V.; Larson, Bryon W.; Whitaker, James B.; Deng, Shihu; Kopidakis, Nikos; Rumbles, Garry; Popov, Alexey A.; Chen, Yu-Sheng; Wang, Xue B.; Boltalina, Olga V.; Strauss, Steven H.
2015-01-01T23:59:59.000Z
Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion of 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)? can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F?. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/?) values of 2 and C60, ?0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/?) of PCBM is ?0.09 V). Time-resolved microwave conductivity charge-carrier yield × mobility values for organic photovoltaic active-layer-type blends of 2 and poly-3-hexylthiophene (P3HT) were comparable to those for equimolar blends of PCBM and P3HT. The structure of solvent-free crystals of 2 was determined by single-crystal X-ray diffraction. The number of nearest-neighbor fullerene–fullerene interactions with centroid...centroid (?...?) distances of ? 10.34 Å is significantly greater, and the average ?...? distance is shorter, for 2 (10 nearest neighbors; ave. ?...? distance = 10.09 Å) than for solvent-free crystals of PCBM (7 nearest neighbors; ave. ?...? distance = 10.17 Å). Finally, the thermal stability of 2 was found to be far greater than that of PCBM.
Baseline avian use and behavior at the CARES wind plant site, Klickitat County, Washington
Erickson, W.P.; Johnson, G.D.; Strickland, M.D.; Kronner, K.; Becker, P.S.; Orloff, S.
2000-01-03T23:59:59.000Z
This report presents a literature review on avian-wind turbine interactions and the results of a one-year avian baseline study conducted in 1998 at the proposed Conservation and Renewable Energy System (CARES) wind development site in Klickitat County, Washington. Avian use of the site ranged from 1.11/survey in the winter to 5.69/survey in the spring. Average use by passerines in the study plots ranged from 1.15 minutes/survey in the winter to 40.98 minutes/survey in the spring. Raptors spent much less time within plots than other groups, ranging from 0.05 minutes/survey in the winter to 0.77 minutes/survey during the fall. Thirteen percent of all flying birds were within the rotor-swept height (25 to 75 m); 41.6% of all raptors were flying at this height. Raptors with the greatest potential turbine exposure are red-tailed hawks and golden eagles. Passerines with the highest turbine exposure are common ravens, American robins, and horned larks. Spatial use data for the site indicate that avian use tends to be concentrated near the rim, indicating that placing turbines away from the rim may reduce risk. Avian use data at the CARES site indicate that if a wind plant is constructed in the future, avian mortality would likely be relatively low.
SITE ENVIRONMENTAL REPORT 2000 (SEPTEMBER 2001).
BROOKHAVEN NATIONAL LABORTORY; PROJECT MANAGER BARBARA COX
2001-09-27T23:59:59.000Z
Brookhaven National Laboratory (BNL) strives for excellence in both its science research and its facility operations. BNL manages its world-class scientific research with particular sensitivity to environmental and community issues through its internationally recognized Environmental Management System (EMS) and award-winning community relations program. The Site Environmental Report 2000 (SER) summarizes the status of the Laboratory's environmental programs and performance, including the steady progress towards cleaning up the Laboratory site and fully integrating environmental stewardship into all facets of BNL's mission. BNL's motto, ''Exploring Earth's Mysteries... Protecting its Future,'' describes how the Laboratory approaches its work, with balance between science and the environment. One of the newest initiatives at the Laboratory, the Upton Ecological and Research Reserve, will permanently preserve 530 acres (212 hectares) of the Long Island Central Pine Barrens, a unique ecosystem of forests and wetlands. The Reserve sets aside 10% of BNL property for conservation and ecological research through a partnership between the U.S. Department of Energy (DOE) and the U.S. Fish and Wildlife Service. The Reserve provides habitat for approximately 27 endangered, threatened, or species of special concern, including the state-endangered eastern tiger salamander, state-threatened banded sunfish, and swamp darter, along with a number of other species found onsite, such as the wild turkey and red-tailed hawk.
Lord, Rexford D
1953-01-01T23:59:59.000Z
on the annular pad of the lens of birds' eyes. rane (1~) cade 0 furthsr Study of the bootes snd Oonolu- ded that tho pooteu ic not derived from the choroid (as had been pre viously believed) and that it ie an intraocular sense organ and is concerned... of fsloonifora birds, X ef' s boriaont;. 2 meet%, . 'r~, 5ees&;l~ gg m?, 4m~ pox'~i~&p ef; the aye ~ 4amQea ieh~4aa eaNa eue ~ xamMe 2Qhc. M~aLu ~4 qgo ++ X eye gf g4t 4~~~ 8y6 'Nip"~s 6~ 4 4+8 Vy'P "Qpp'. ' y Cps ~ pad cv Rect C X - Keie X4fo...
Ecological Monitoring and Compliance Program Fiscal Year 2000 Report
Wills, C.A.
2000-12-01T23:59:59.000Z
The Ecological Monitoring and Compliance program, funded through the U.S. Department of Energy, Nevada Operations Office, monitors the ecosystem of he Nevada Test Site (NTS) and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program's activities conducted by Bechtel Nevada during fiscal year 2000. Program activities included: (1) biological surveys at proposed construction sites, (2) desert tortoise compliance,(3) ecosystem mapping, (4) sensitive species and unique habitat monitoring, and (5) biological monitoring at the HAZMAT Spill Center. Biological surveys for the presence of sensitive species were conducted for 24 NTS projects. Seventeen sites were in desert tortoise habitat, and six acres of tortoise habitat were documented as being disturbed this year. No tortoises were found in or displaced from project areas, and no tortoises were accidentally injured or killed. A topical report describing the classification of habitat types o n the NTS was completed. The report is the culmination of three years of field vegetation mapping and the analysis of vegetation data from over 1,500 ecological landform units. A long-term monitoring plan for important plant species that occur on the NTS was completed. Sitewide inventories were conducted for the western burrowing owl, bat species of concern, wild horses, raptor nests, and mule deer. Fifty-nine of 69 known owl burrows were monitored. Forty-four of the known burrows are in disturbed habitat. As in previous years, some owls were present year round on the NTS. An overall decrease in active owl burrows was observed within all three ecoregions (Mojave Desert, Transition, Great Basin Desert) from October through January. An increase in active owl burrows was observed from mid-March to early April. A total of 45 juvenile owls was detected from eight breeding pairs. One nest burrow was detected in the Mojave Desert,one in the Great Basin Desert, and six in the Transition ecoregion. Seventy bats, representing four bat species of concern, were captured in mist-nets at water sources in the Great Basin Desert ecoregion. Bats were detected with the Anabat II call-recording system at selected tunnel and mine entrances verifying that some NTS mines and tunnels are used as bat roosts. Thirty-seven adult horses and 11 foals were counted this year. Four of the five foals observed last year have survived to yearlings. A monitoring plan for NTS horses was completed. Six active red-tailed hawk nests and 10 nestling red-tailed hawks were detected this year. Two spotlighting surveys for mule deer were conducted, each over three consecutive nights in October 1999 and August 2000. The mean sighting rate in October was 1.2 deer/10 kilometers (km) and 1.6 deer/10 km in August. Selected wetlands and man-made water sources were monitored for physical parameters and wildlife use. No dead animals were observed this year in any plastic-lined sump. Pahute Mesa Pond was confirmed to have vegetation,hydrology, and soil indicators that qualify the site as a jurisdictional wetland. The chemical spill test plan for one experiment at the HAZMAT Spill Center was reviewed for its potential to impact biota downwind of spills on Frenchman Lake playa.
CHI-SQUARE TEST STATISTICS AND DERIVED MEASURES OF EFFECT FOR HAWKS, RAPTORS, AND ALL BIRDS
* Faces wind 155 134.08 1.16 9 Away from wind 84 98.97 0.85 -6 Vertical axis 4 9.96 0.40 -2 Blade color.91 -2 2780 - 3287 163 147.24 1.11 6 4014 - 5646 6 3.89 1.54 1 Tower type * Vertical axis 4 9.96 0 and Attribute Observed Expected Obs ÷ Exp Accountable percent Turbine model* Micon 14 17.29 0.81 -1 Bonus 83 68
Princeton University March 9, 1987 DOE/ER/3072-41 THE HAWKING-UNRUH TEMPERATURE
McDonald, Kirk
during the radiation of accel- erated particles, particularly those in storage rings. This view FLUCTUATIONS IN PARTICLE ACCELERATORS K. T. McDonald Joseph Henry Laboratories, Princeton University, Princeton on the details of the accelerating force, nor of the nature of the accelerated particle. The idea of an effective
Doomed to die? Predicting extinction risk in the true hawks Accipitridae
Krüger, Oliver
is identifying species at risk from extinction and establishing the most likely factors influencing this risk with lower extinction risk and larger population and range sizes. Species with special habitat requirements the size of the species' gene pool and could be a good marker of extinction risk. The analyses also
IR Renormalisation of General Effective Actions and Hawking Flux in 2D Gravity Theories
D. Hofmann; W. Kummer
2005-12-29T23:59:59.000Z
The infrared problem of the effective action in 2D is discussed in the framework of the Covariant Perturbation Theory. The divergences are regularised by a mass and the leading term is evaluated up to the third order of perturbation theory. A summation scheme is proposed which isolates the divergences from the finite part of the series and results in a single term. The latter turns out to be equivalent to the coupling to a certain classical external field. This suggests a renormalisation by factorisation.
Igneous activity in the southern highlands of the Moon B. Ray Hawke,1
Spudis, Paul D.
that Buch B is an impact structure, not a volcanic vent. The optical maturity image shows that the Buch B ejecta deposits are immature and the radar and thermal data indicate a high abundance of fresh rocks-haloed and dark-rayed craters were the sources of much controversy. Most lunar scientists supported a vol- canic
Hawking radiation as tunneling from a Vaidya black hole in noncommutative gravity
Mehdipour, S. Hamid [Islamic Azad University, Lahijan Branch, P. O. Box 1616, Lahijan (Iran, Islamic Republic of)
2010-06-15T23:59:59.000Z
In the context of a noncommutative model of coordinate coherent states, we present a Schwarzschild-like metric for a Vaidya solution instead of the standard Eddington-Finkelstein metric. This leads to the appearance of an exact (t-r) dependent case of the metric. We analyze the resulting metric in three possible causal structures. In this setup, we find a zero remnant mass in the long-time limit, i.e. an instable black hole remnant. We also study the tunneling process across the quantum horizon of such a Vaidya black hole. The tunneling probability including the time-dependent part is obtained by using the tunneling method proposed by Parikh and Wilczek in terms of the noncommutative parameter {sigma}. After that, we calculate the entropy associated to this noncommutative black hole solution. However, the corrections are fundamentally trifling; one could respect this as a consequence of quantum inspection at the level of semiclassical quantum gravity.
Statistiques de motifs en gnomique. Le processus de Hawkes : un exemple de
Reynaud-Bouret, Patricia
, sequence of nucleotides Â· Nucleotides: A(denine), C(ytosine), G(uanine), T of nucleotides Â· Nucleotides: A(denine), C(ytosine), G(uanine), T(hymine). Â· Motif (= oligonucleotides): short sequence of nucleotides, e.g. CAGTAG TAGACAGATAGACGAT CAGTAG CCAGTAGACAGTAGGCATGA. . . ANR ATLAS, Nice, 16
The Hampering Active Wellbore Kit (HAWK) for rapidly controlling a free flowing oil well
Rojas, Folkers Eduardo
2014-01-01T23:59:59.000Z
To mitigate the impact of a Blowout Preventer (BOP) failure, this work proposes a method and machine that can create a gradual flow reduction to zero in an offshore well by introducing a mechanical plug inside the BOP. The ...
A Parallel Document Retrieval Server For The World Wide D. Hawking P. Bailey
Hawking, David
Cooperative Research Centre For Advanced Computational Systems Department of Computer Science The Australian select from a rich set of alternative functions for computing the relevance of documents. It has been attributes permit extremely fast construction of inverted #12;les and similarly fast searches using them
Proximity Operators -So Near And Yet So Far David Hawking and Paul Thistlewaite
Hawking, David
-operative Research Centre For Advanced Computational Systems Department Of Computer Science Australian National-disk-resident inverted #12;le indexes and dictionaries has potentially extended data handling capacity to the terabyte an earlier ANU parallel system called PADDY [3, 12] which included a partial emulation of the functionality
Two Causal Analyses of the Black Hawk Shootdown during Operation Provide Comfort
Ladkin, Peter B.
in such a way as to cause a loss of ma- teriel or people. It is part of the safety-critical engi- neering task to analyse systems to attempt to avoid such losses. In turn, part of this task is to under- stand loss technical - indeed the single purely technical contribution to the unfortunate event remains unexplained
Reduced MHC and neutral variation in the Galapagos hawk, an island endemic
Bollmer, Jennifer L; Hull, Joshua M; Ernest, Holly B; Sarasola, José H; Parker, Patricia G
2011-01-01T23:59:59.000Z
RT, Whiteman NK, Sarasola JH, Parker PG: Phylogeography ofBechard MJ, Houston CS, Sarasola JH, England AS: Swainson’sSem Immunol 1994, 61. Sarasola JH, Negro JJ, Hobson KA,
A Note on Black Hole Temperature and Entropy
P. R. Silva
2006-05-09T23:59:59.000Z
We propose intuitive derivations of the Hawking temperature and the Bekenstein-Hawking entropy of a Schwarzschild black hole.
TheUniversityofKansas New Student Orientation
Lawrence, KS 66045-7594 (785) 864-4270 Hawk Week Contributors Coca-Cola New Student Orientation Hawk Week
Ecological Monitoring and Compliance Program Fiscal Year 2002 Report
C. A. Wills
2002-12-01T23:59:59.000Z
The Ecological Monitoring and Compliance program, funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office, monitors the ecosystem of the Nevada Test Site (NTS) and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program's activities conducted by Bechtel Nevada (BN) during fiscal year 2002. Program activities included: (1) biological surveys at proposed construction sites, (2) desert tortoise compliance, (3) ecosystem mapping and data management, (4) sensitive species and unique habitat monitoring, and (5) biological monitoring at the HAZMAT Spill Center. Biological surveys for the presence of sensitive species and important biological resources were conducted for 26 NTS projects. These projects have the potential to disturb a total of 374 acres. Thirteen of the projects were in desert tortoise habitat, and 13.38 acres of desert tortoise habitat were disturbed. No tortoises were found in or displaced from project areas, and no tortoises were accidentally injured or killed at project areas or along paved roads. Compilation of historical wildlife data continued this year in efforts to develop faunal distribution maps for the NTS. Photographs associated with the NTS ecological landform units sampled to create the NTS vegetation maps were cataloged for future retrieval and analysis. The list of sensitive plant species for which long-term population monitoring is scheduled was revised. Six vascular plants and five mosses were added to the list. Plant density estimates from ten populations of Astragalus beatleyae were collected, and eight known populations of Eriogonum concinnum were visited to assess plant and habitat status. Minimal field monitoring of western burrowing owl burrows occurred. A report relating to the ecology of the western burrowing owl on the Nevada Test Site was prepared which summarizes four years of data collected on this species' distribution, burrow use, reproduction, activity patterns, and food habits. Bat roost sites within seven buildings slated for demolition were identified, and a BN biologist was a contributing author of the Nevada Bat Conservation Plan published by the Nevada Bat Working Group. Thirty-three adult horses and five foals were counted this year. Six active raptor nests (two American kestrel, two Red-tailed hawk, and two Great-horned owl nests) were found and monitored this year. Selected wetlands and man-made water sources were monitored for physical parameters and wildlife use. No dead animals were observed this year in any plastic-lined sump. The chemical release test plan for one experiment at the HAZMAT Spill Center on Frenchman Lake playa was reviewed. Seasonal sampling of downwind and upwind transects near the spill center was conducted to document baseline conditions of biota.
Analogue Hawking Radiation in a dc-SQUID Array Transmission Line P. D. Nation,1,* M. P. Blencowe,1
Buks, Eyal
) where cs is the speed of sound and vÃ°rÃ? is the spatially varying velocity of the fluid. For a sound wave system was first sug- gested by Unruh who uncovered the analogy between sound waves in a fluid been proposed using Bose- Einstein condensates [4], liquid Helium [5], electromag- netic transmission
Reprinted from The Very Early Universe. Edited by G.W.Gibbons S.W.Hawking and S.Siklos
Linde, Andrei
University Press 1983 #12;Linde: The new inflationary Universe scenario Friedmann universe expands up to some-dimensional space-time at d > 4 any bounded systems such as atoms or planetary #12;Linde: The new inflationary
OscarAndrewHammersteinIIITheHammersteins:AMusicalTheatreFamily University of Delaware
Kirby, James T.
Noodles and Grilled Asparagus OR Pan-seared Scallion Crusted Red Tail Sea Bass with Lemon-roasted Heirloom - Please Select One* Member(s) __________________________________ Pork Fish Vegetarian First Last _______________________________________________ Pork Fish Vegetarian First Last Guest(s) ____________________________________ Pork Fish Vegetarian
Ecological Monitoring and Compliance Program Fiscal Year 2001
C. A. Wills
2001-12-01T23:59:59.000Z
The Ecological Monitoring and Compliance program, funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office, monitors the ecosystem of the Nevada Test Site (NTS) and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program's activities conducted by Bechtel Nevada during fiscal year 2001. Program activities included: (1) biological surveys at proposed construction sites, (2) desert tortoise compliance, (3) ecosystem mapping and data management, (4) sensitive species and unique habitat monitoring, and (5) biological monitoring at the HAZMAT Spill Center. Biological surveys for the presence of sensitive species were conducted for 23 NTS projects. Eleven sites were in desert tortoise habitat. These projects have the potential to disturb a total of 588 acres, where 568 acres of disturbance would be off-road driving. No tortoises were found in or displaced from project areas, and no tortoise s were accidentally injured or killed at project areas. One tortoise was crushed by a vehicle on a paved road. A topical report describing the classification of habitat types on the NTS was completed and distributed. The report is the culmination of three years of field vegetation mapping and the analysis of vegetation data from over 1,500 ecological landform units. Compilation of historical wildlife data was initiated. A long-term monitoring plan for important plant species that occur on the NTS was completed. Site-wide monitoring was conducted for the western burrowing owl, bat species of concern, wild horses, and raptor nests. Sixty-nine of 77 known owl burrows were monitored. As in previous years, some owls were present year round on the NTS. An overall decrease in active owl burrows was observed within all three ecoregions (Mojave Desert, Transition, Great Basin Desert) from October through January. An increase in active owl burrows was observed from mid March to early April. A total of 55 juvenile owls was detected from 11 breeding pairs. Pellet analysis of burrowing owls was completed which identified key prey species. A total of 272 bats, representing 10 bat species were captured in mist-nets at water sources in the Great Basin Desert ecoregion. Bats were detected with the Anabat II call-recording system at water sources and selected tunnel and mine entrances. Thirty-seven adult horses and 11 foals were counted this year. Two of the eleven foals observed last year survived to yearlings. Seven active raptor nests were found and monitored this year. These included two Great-horned Owl nests, three Barn Owl nests, and two Red-tailed Hawk nests. Selected wetlands and man-made water sources were monitored for physical parameters and wildlife use. No dead animals were observed this year in any plastic-lined sump. The chemical spill test plans for four experiments at the HAZMAT Spill Center were reviewed for their potential to impact biota downwind of spills on Frenchman Lake playa.
WORKSHOP ON NEW VIEWS OF THE MOON
Rathbun, Julie A.
Hawke University of Hawai'i Jim Head Brown University Brad Jolliff Washington University Paul Lucey. Campbell, D. B. Campbell, T. W. Thompson, and B. R. Hawke ....................................23 Another
H.H. Horne Co.
2011-09-05T23:59:59.000Z
functional forms are investigated in order to select an appropriate one that could more accurately model pedestrian delay. The minimum green time for vehicles, as an important variable in the HAWK pedestrian delay model and a peculiar element in HAWK...
TheCondor96:4SS-467 0 The CooperOrnithologicalSociety1994
-skinnedHawk (Accipiterstriates)pairsnestingin aspen(Populustremuloides),conifer (Abies,Picea spp.), and mixed aspen, Sharp-shinned Hawks breed in quaking aspen (Populustremuloides)and conifer (Abies,Picea, Pseudotsuga)forests.Forests in which hunting Sharp-shinned Hawks have been observed in- clude mature aspen, conifer, and mixed aspen
Electronic Phase Control with an Electric Field | Stanford Synchrotron...
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Electronic Phase Control with an Electric Field Wednesday, April 29, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Hongtao Yuan, Stanford University Program...
2012 Environmental/Radiological Assistance Directory (ERAD) Presentati...
Tool, June 27, 2012; Himanshu Upadhyay May 2012; Integrated Cloud Based Environmental Data Management System; Penny Gomez, Karen Schultz Paige, Chris EchoHawk Los Alamos...
Molecular architecture and functionalization of graphene surface...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Molecular architecture and functionalization of graphene surface; Synthesis and characterization Wednesday, November 12, 2014 - 3:00pm SLAC, Redtail Hawk Conference Room 108A...
Electronic and structural dynamics in transition metal complexes...
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Electronic and structural dynamics in transition metal complexes - recent results from synchrotron and XFEL experiments Wednesday, March 4, 2015 - 3:00pm SLAC, Redtail Hawk...
Probing attosecond electron dynamics at solid surfaces | Stanford...
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Probing attosecond electron dynamics at solid surfaces Wednesday, May 13, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Jrg Osterwalder, Department of Physics,...
NETL Researcher Honored with 2013 Federal Laboratory Consortium...
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Jeffrey Hawk of the National Energy Technology Laboratory (NETL) has been awarded a Far West region Federal Laboratory Consortium (FLC) award for Outstanding Technology Development...
Vector particles tunneling from BTZ black holes
Ge-Rui Chen; Shiwei Zhou; Yong-Chang Huang
2014-09-21T23:59:59.000Z
In this paper we investigate vector particles' Hawking radiation from a BTZ black hole. By applying the WKB approximation and the Hamilton-Jacobi Ansatz to the Proca equation, we obtain the tunneling spectrum of vector particles. The expected Hawking temperature is recovered.
Correlation, entropy, and information transfer in black hole radiation
Baocheng Zhang; Qingyu Cai; Mingsheng Zhan; Li You
2014-03-28T23:59:59.000Z
Since the discovery of Hawking radiation, its consistency with quantum theory has been widely questioned. In the widely described picture, irrespective of what initial state a black hole starts with before collapsing, it eventually evolves into a thermal state of Hawking radiations after the black hole is exhausted. This scenario violates the principle of unitarity as required for quantum mechanics and leads to the acclaimed "information loss paradox". This paradox has become an obstacle or a reversed touchstone for any possible theory to unify the gravity and quantum mechanics. Based on the results from Hawking radiation as tunneling, we recently show that Hawking radiations can carry off all information about the collapsed matter in a black hole. After discovering the existence of information-carrying correlation, we show in great detail that entropy is conserved for Hawking radiation based on standard probability theory and statistics. We claim that information previously considered lost remains hidden inside Hawking radiation. More specifically, it is encoded into correlations between Hawking radiations. Our study thus establishes harmony between Harking radiation and the unitarity of quantum mechanics, which establishes the basis for a significant milestone towards resolving the long-standing information loss paradox. The paper provides a brief review of the exciting development on Hawking raidation. In addition to summarize our own work on this subject, we compare and address other related studies.
Scalar emission in a rotating Gödel black hole
Songbai Chen; Bin Wang; Jiliang Jing
2008-08-23T23:59:59.000Z
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.
Attractor Explosions and Catalyzed Vacuum Decay
Green, Daniel; Silverstein, Eva; Starr, David
2006-05-05T23:59:59.000Z
We present a mechanism for catalyzed vacuum bubble production obtained by combining moduli stabilization with a generalized attractor phenomenon in which moduli are sourced by compact objects. This leads straightforwardly to a class of examples in which the Hawking decay process for black holes unveils a bubble of a different vacuum from the ambient one, generalizing the new endpoint for Hawking evaporation discovered recently by Horowitz. Catalyzed vacuum bubble production can occur for both charged and uncharged bodies, including Schwarzschild black holes for which massive particles produced in the Hawking process can trigger vacuum decay. We briefly discuss applications of this process to the population and stability of metastable vacua.
Marine Biology International Journal on Life in Oceans
Florida, University of
. Godfrey Â· Brendan J. Godley Â· Lucy A. Hawkes Â· Thomas M. Murphy Â· Kristina L. Williams Â· Matthew J. Witt Department of Natural Resources, Mount Pleasant, SC 29464, USA e-mail: dubosegriffin@seaturtle.org Present
Amyloid diffraction at XFELs | Stanford Synchrotron Radiation...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
April 1, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Meng Liang, LCLS Program Description Amyloid fibers are formed when segments of proteins self-assemble...
Dawn of x-ray nonlinear optics | Stanford Synchrotron Radiation...
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Dawn of x-ray nonlinear optics Wednesday, July 8, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: David Reis, PULSE Program Description X-ray free electron lasers...
Recent advances in reflective optics for EUV/x-ray light sources...
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Recent advances in reflective optics for EUVx-ray light sources Wednesday, June 24, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Regina Soufli, LLNL Program...
Imaging Quantum States with X-ray Compton Scattering | Stanford...
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Imaging Quantum States with X-ray Compton Scattering Wednesday, April 8, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Yoshiharu Sakurai (Japan Synchrotron...
MITRADASMPANICKER 6 Transplantation of neuronal cells in animal models of neurological damage
Udgaonkar, Jayant B.
in moths. Science, 315, 863-866. The hawk moth, Manduca sexta, feeding while hovering over an artificial-wing flight of airplanes. From these studies, we were able to show that the high lift generated by flapping
Time at the origin of the Universe: fluctuations between two possibilities
V. Dzhunushaliev
2002-06-20T23:59:59.000Z
A variation of Hawking's idea about Euclidean origin of a nonsingular birth of the Universe is considered. It is assumed that near to zero moment $t = 0$ fluctuations of a metric signature are possible.
analogue space environment: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Hawking process. P. D. Nation; M. P. Blencowe; A. J. Rimberg; E. Buks 2009-04-16 108 Impacts of The Radiation Environment At L2 On Bolometers Onboard The Herschel Space...
Micromechanical actuators for insect flight mechanics
Zhou, Hui, M.S. Massachusetts Institute of Technology
2008-01-01T23:59:59.000Z
This project aims to develop MEMS actuators to aid in the study of insect flight mechanics. Specifically, we are developing actuators that can stimulate the antennae of the crepuscular hawk moth Manduca Sexta. The possible ...
Cybersecurity and the Smarter Grid (2014)
Broader source: Energy.gov [DOE]
An article by OE’s Carol Hawk and Akhlesh Kaushiva in The Electricity Journal discusses cybersecurity for the power grid and how DOE and the energy sector are partnering to keep the smart grid reliable and secure.
anomalies congenitales des: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
regularization and is found to vanish. Hung cheng; S. P. Li 1996-03-06 188 Hawking Radiation of Black Rings from Anomalies General Relativity & Quantum Cosmology (arXiv)...
Tutorial: The Basics of SAXS Data Analysis | Stanford Synchrotron...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Tutorial: The Basics of SAXS Data Analysis Thursday, November 17, 2011 - 1:00pm SLAC, Redtail Hawk Conference Room 108A Dr. Alexander V. Shkumatov, Biological Small Angle...
Joint Environmental Assessment of the California Department of...
Broader source: Energy.gov (indexed) [DOE]
e. Bats 4 Page No. f. California Condor; Birds of Prey-Hawks, Eagles, Falcons g. Fish. h. Desert Pupfish i. San Joaquin Dune Beetle, Andrew's Dune Scarab Beetle; Ciervo...
Rank, Jeffery Aaron
2001-01-01T23:59:59.000Z
momentous than the threat of global climate change. " So begins a recent open letter to President Bush (Carter, et al, , 2001). Signatories include Mikhail Gorbachev, Stephen Hawking, Harrison Ford, Jimmy Carter, George Soros, John Glenn, Jane Goodall...
Questions for IIT Waste Diversion RFP Question: What are the recycling/waste goals of IIT?
Heller, Barbara
for commercial weights? We cannot provide exact weights by location for commercial cans due to rear load trucks expected to haul the Black outside Hawk bins? Answer: No, this is handled by our staff. Question: Have you
Bartol Booz Allen Hamilton Rama Moorthy Hatha Systems June 2010 U.S. Department of Commerce Gary Locke, and Nadya Bartol, Booz Allen and Hamilton, would like to thank Mike Hawk, Department of State for his
Experimental Possibilities in Material Science enabled by FEL...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Experimental Possibilities in Material Science enabled by FEL Sources Wednesday, July 1, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: Joerg Hallmann, XFEL Program...
Design of Sensor Standards for RQ-7B Shadow under Loss-Link
,000 RADAR > 250 Global Hawk Group 2 ,000 250 Pioneer Dragonfly Eagle Eye Group 4 Onboard Ground Control Station Collision Avoidance See-and-Avoid Sense-and-Avoid (SAA) Visual Scanning
Lunar Missions, Science, & Astronauts! Interplanetary/Lunar Transfer!
Stengel, Robert F.
: Stevenson doves and Symington hawks" !! Warfare had become politicized and democratized" !! Nuclear weapons and power" !! Ike didn't buy it" !! Impacts of the 1960 Presidential election" !! U-2 flights found
accelerated hyperfractionated thoracic: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
at accelerators HEP - Phenomenology (arXiv) Summary: This is my contribution to the proceedings of Stephen Hawking's 60th birthday celebration. If the ideas of TeV scale gravity...
Utilizing Standing Ultrasonic Waves to Harvest Microalgae from a Fluid Suspension
Loveless, Kolin, 1986-
2010-07-14T23:59:59.000Z
timeconsuming, and centrifugation requires significant energy input and frequent repairs. Here, the ultrasonic cell separation techniques employed by Jeremy J. Hawkes and others are applied to the specific case of separating microalgae from a fluid medium...
A 1-mW vibration energy harvesting system for moth flight-control applications
Chang, Samuel C
2010-01-01T23:59:59.000Z
This thesis focuses on the approach and methodologies required to build a 1-mW energy-harvesting system for moth flight control applications. The crepuscular hawk moth Manduca sexta is the chosen test subject. This project ...
KKW Analysis for the Dyadosphere of a Charged Black Hole
I. Radinschi
2005-11-28T23:59:59.000Z
The Keski-Vakkuri, Kraus and Wilczek (KKW) analysis is used to compute the temperature and entropy in the dyadosphere of a charged black hole solution. For our purpose we choose the dyadosphere region of the Reissner-Nordstrom black hole solution. Our results show that the expressions of the temperature and entropy in the dyadosphere of this charged black hole are not the Hawking temperature and the Bekenstein-Hawking entropy, respectively.
Thermodynamics of Schwarzschild-de Sitter black hole: thermal stability of Nariai black hole
Yun Soo Myung
2008-03-28T23:59:59.000Z
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.
Publications of the Hawaii Institute of Geophysics and Planetology University of Hawaii
. Taylor, F. Martinez, R. Hey, K. Maeda, and K. Ohno, Synchronous reorientation of the Woodlark Basin. Blewett, D.T., Lucey P.G., and Hawke B.R., Ling G.G., and Robinson M.S. (1997) A comparison of mercurian, and B.R. Hawke, 1997, Clementine images of the lunar sample-return stations: Refinement of FeO and Ti
Local temperature for dynamical black holes
Sean A. Hayward; R. Di Criscienzo; M. Nadalini; L. Vanzo; S. Zerbini
2008-12-13T23:59:59.000Z
A local Hawking temperature was recently derived for any future outer trapping horizon in spherical symmetry, using a Hamilton-Jacobi tunneling method, and is given by a dynamical surface gravity as defined geometrically. Descriptions are given of the operational meaning of the temperature, in terms of what observers measure, and its relation to the usual Hawking temperature for static black holes. Implications for the final fate of an evaporating black hole are discussed.
Absorption cross section of RN black hole
Sini R.; V. C. Kuriakose
2007-08-23T23:59:59.000Z
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.
The coordinate coherent states approach revisited
Miao, Yan-Gang, E-mail: miaoyg@nankai.edu.cn; Zhang, Shao-Jun, E-mail: sjzhang@mail.nankai.edu.cn
2013-02-15T23:59:59.000Z
We revisit the coordinate coherent states approach through two different quantization procedures in the quantum field theory on the noncommutative Minkowski plane. The first procedure, which is based on the normal commutation relation between an annihilation and creation operators, deduces that a point mass can be described by a Gaussian function instead of the usual Dirac delta function. However, we argue this specific quantization by adopting the canonical one (based on the canonical commutation relation between a field and its conjugate momentum) and show that a point mass should still be described by the Dirac delta function, which implies that the concept of point particles is still valid when we deal with the noncommutativity by following the coordinate coherent states approach. In order to investigate the dependence on quantization procedures, we apply the two quantization procedures to the Unruh effect and Hawking radiation and find that they give rise to significantly different results. Under the first quantization procedure, the Unruh temperature and Unruh spectrum are not deformed by noncommutativity, but the Hawking temperature is deformed by noncommutativity while the radiation specturm is untack. However, under the second quantization procedure, the Unruh temperature and Hawking temperature are untack but the both spectra are modified by an effective greybody (deformed) factor. - Highlights: Black-Right-Pointing-Pointer Suggest a canonical quantization in the coordinate coherent states approach. Black-Right-Pointing-Pointer Prove the validity of the concept of point particles. Black-Right-Pointing-Pointer Apply the canonical quantization to the Unruh effect and Hawking radiation. Black-Right-Pointing-Pointer Find no deformations in the Unruh temperature and Hawking temperature. Black-Right-Pointing-Pointer Provide the modified spectra of the Unruh effect and Hawking radiation.
Shenanigans at the black hole horizon: pair creation or Boulware accretion?
Israel, Werner
2015-01-01T23:59:59.000Z
The current scenario of black hole evaporation holds that the Hawking energy flux $F$ is powered by pair creation at the horizon. However, pair creation produces entanglements, some of which must necessarily be broken before the black hole evaporates completely. That leads to loss of information and violation of unitarity. In this paper, an alternative scenario is suggested that reproduces the essential features of Hawking evaporation, but does not invoke pair creation with its attendant problems. In this "accreting Boulware" scenario, a positive flux $F$ is still an outflux at infinity, but near the horizon it becomes an influx of negative energy. This negative energy flux (marginally) satisfies the Flanagan energy inequality.
Some remarks on black hole thermodynamics
R. Y. Chiao
2011-02-04T23:59:59.000Z
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.
Cardy-Verlinde formula for an axially symmetric dilaton-axion black hole
Mubasher Jamil; M. Akbar; M. R. Setare
2011-05-30T23:59:59.000Z
It is shown that the Bekenstein-Hawking entropy of an axially symmetric dilaton-axion black hole can be expressed as a Cardy-Verlinde formula. By utilizing the first order quantum correction in the Bekenstein-Hawking entropy we find the modified expressions for the Casimir energy and pure extensive energy. The first order correction to the Cardy-Verlinde formula in the context of axially symmetric dilaton-axion black hole are obtained with the use of modified Casimir and pure extensive energies.
Thermodynamics of 5D dilaton-gravity
Megias, E. [Institute for Theoretical Physics, University of Heidelberg (Germany); Instituto de Fisica Teorica CSIC-UAM, Universidad Autonoma de Madrid (Spain)
2011-05-23T23:59:59.000Z
We calculate the free energy, spatial string tension and Polyakov loop of the gluon plasma using the dilaton potential of Ref. [1] in the dilaton-gravity theory of AdS/QCD. The free energy is computed from the Black Hole solutions of the Einstein equations in two ways: first, from the Bekenstein-Hawking proportionality of the entropy with the area of the horizon, and secondly from the Page-Hawking computation of the free energy. The finite temperature behaviour of the spatial string tension and Polyakov loop follow from the corresponding string theory in AdS{sub 5}. Comparison with lattice data is made.
A note on the string spectrum at the Hagedorn temperature
J. D. Madrigal; P. Talavera
2009-05-21T23:59:59.000Z
We discuss semi-classical string configurations at finite temperature. We find that those soliton solution in the background describing type IIA strings disappear or become divergent when we approach the Hagedorn temperature in the strong coupling regime. These findings together with a semi-classical analysis for the Hawking radiation let us to think that Hawking radiation is mainly driven by the existence of highly excited states. As by side, we check that beside the thermodynamical instability the system is dynamical unstable before reaching the Hagedorn temperature.
Heller, Barbara
Finance Requests Telling the Office of Campus Life how to spend money will look a little different) Funding Request: This is how you will request money from Finance Board. Be sure to meet with your Finance Financial Requests 1. Log in to your HawkLink account. 2. Go to your organization's page. 3. Go to Finance
Mathl. Comput. Modelling Vol. 27, No. 4, pp. 99-108, 1998 Copyright@1998 Elsevier Science Ltd
Alvarez, Nadir
system, or to micro-climates such as a dry hot rock versus a cool, damp crack. With such a system the dynamics and solve the system analytically. Contrary to the homogeneous hawk-dove model, for certain being a dove. On the whole, the homogeneous case allows analytical progress, and consequently, a good
Adrian C. Ottewill; Peter Taylor
2010-10-19T23:59:59.000Z
We calculate the renormalized vacuum polarization and stress tensor for a massless, arbitrarily coupled scalar field in the Hartle-Hawking vacuum state on the horizon of a Schwarzschild black hole threaded by an infinte straight cosmic string. This calculation relies on a generalized Heine identity for non-integer Legendre functions which we derive without using specific properties of the Legendre functions themselves.
ICEPT Working Paper Comparison of Fuel Cell and Combustion Micro-CHP under Future Residential
ICEPT Working Paper Comparison of Fuel Cell and Combustion Micro-CHP under Future Residential and Combustion Micro-CHP under Future Residential Energy Demand Scenarios A.D. Hawkes2 and M.A. Leach Centre heat and power (micro-CHP) - a technology to provide heat and some electricity to individual
Mon. Not. R. Astron. Soc. 313, L9L13 (2000) Evidence for transverse spread in Leonid meteors
Brown, Peter
. LeBlanc,1w Â² I. S. Murray,1 Â³ R. L. Hawkes,1 P. Worden2 , M. D. Campbell,3 P. Brown,3 P. Jenniskens,4 and longitudinal spread in the fragments owing to a more complex fluid interaction (Brown et al. 1994
Meteoritics & Planetary Science 35, 1259-1267 (2000) Meteoritical Society, 2000. Printed in USA.
Brown, Peter
and physical structure M. D. CAMPBELL1*, P. G. BROWN1, A. G. LEBLANC2, R. L. HAWKES2, J. JONES1, S. P. WORDEN3 Brunswick E4L 1E6, Canada 3Headquarters United States Air Force, 1480 Air Force Pentagon, Washington, D, Washington, D.C. 20546, USA Present address: Department of Astronomy and Physics, Saint Mary's University
GLOBAL GROUND-BASED ELECTRO-OPTICAL AND RADAR OBSERVATIONS OF THE 1999 LEONID SHOWER
Brown, Peter
P. BROWN1 , M.D. CAMPBELL1 , K.J. ELLIS2 , R.L. HAWKES3, *, J. JONES1 , P. GURAL4 , D. BABCOCK3, D. JEWELL17, A. JONES1, M. LEAKE6, A.G. LEBLANC3, 18 , J.K. LOOPER6 , B.A. MCINTOSH19 , T. MONTAGUE
Web Information Retrieval Author Preprint for Web
Hawking, David
Web Information Retrieval Author Preprint for Web Nick Craswell and David Hawking 18 April 2009 1 Introduction This chapter outlines some distinctive characteristics of web information re- trieval, starting with a broad description of web data and the needs of web searching users, then working through ranking
BSA Profile Are you looking for some of the most highly-regarded Bachelor of Accountancy
Hart, Gus
audit competition. 4) Flexibility: With strong language ability (about two-thirds speak a second served Profile20132013 #12;BSAcc RECRUITERS BSAcc ACHIEVEMENTS A team of Brigham Young University undergraduateGladrey Sage Creek Partners Sempra Energy Swarts & Swarts CPAs TaxHawk U.S. Army Wells Fargo- Real Est. Cap
Single mimivirus particles intercepted and imaged with an X-ray laser (CXIDB ID 2)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Seibert, M. Marvin; Ekeberg, Tomas
These are the files used to reconstruct the images in the paper "Single Mimivirus particles intercepted and imaged with an X-ray laser". Besides the diffracted intensities, the Hawk configuration files used for the reconstructions are also provided. The files from CXIDB ID 2 are the pattern and configuration files for the pattern showed in Figure 2b in the paper.
WAVENET : Nearshore Wave Recording Network for
WAVENET : Nearshore Wave Recording Network for England and Wales Feasibility Study P J Hawkes R Atkins A H Brampton D Fortune R Garbett B P Gouldby Report TR 122 April 2001 #12;#12;WAVENET : Nearshore 05/03/02 Summary WAVENET : Nearshore Wave Recording Network for England and Wales Feasibility Study P
Snavely, Allan
Diamond 2. ARL Harold 3. ARL Harold 3. MHPCC Mana 4. NAVY Davinci 4. NAVY Davinci 5. NAVY Einstein 5. NAVY. NAVY Babbage 10. NAVY Babbage 10. ARL Hawk Since Mana runs AMR Standard 128 more than 2x faster than
, aud will set the nets 08 Taiigier Souucl to-night; Cherrystone, to-morrow night; Torli River HAWK, patiixent River, &!wuary 28, 1882. My report of February 25 closed at 9.45 a. me At 10 a. m. me com- menced dredgiiig in t'he decpest water at the mouth of the Patuxent ll,iver to ascertain what
Holographic duality (or the AdS/CFT correspondence), originally proposed by
holographic dual of quantum chromodynamics is not yet known), are particularly valuable because this problem in this exciting field. It attracted an unusually diverse group, including general relativity experts, high energy correspond to heating up the boundary quantum matter. This is closely related to Hawking's famous discovery
Quantum Creation of an Open Inflationary Universe
Andrei Linde
1998-05-25T23:59:59.000Z
We discuss a dramatic difference between the description of the quantum creation of an open universe using the Hartle-Hawking wave function and the tunneling wave function. Recently Hawking and Turok have found that the Hartle-Hawking wave function leads to a universe with Omega = 0.01, which is much smaller that the observed value of Omega > 0.3. Galaxies in such a universe would be about $10^{10^8}$ light years away from each other, so the universe would be practically structureless. We will argue that the Hartle-Hawking wave function does not describe the probability of the universe creation. If one uses the tunneling wave function for the description of creation of the universe, then in most inflationary models the universe should have Omega = 1, which agrees with the standard expectation that inflation makes the universe flat. The same result can be obtained in the theory of a self-reproducing inflationary universe, independently of the issue of initial conditions. However, there exist two classes of models where Omega may take any value, from Omega > 1 to Omega << 1.
Wood, Robert
A novel low-profile shape memory alloy torsional actuator This article has been downloaded from.1088/0964-1726/19/12/125014 A novel low-profile shape memory alloy torsional actuator Jamie K Paik1 , Elliot Hawkes1,2 and Robert J. The primary actuator material is thermally activated NiTi shape memory alloy (SMA), which exhibits remarkably
Reordering an index to speed query processing without loss of effectiveness.
Hawking, David
Funnelback Pty Ltd. Canberra ACT 2602, Australia, and RsCS, Australian National University david.hawking@acm.org Timothy Jones Funnelback Pty Ltd. Melbourne VIC 3066, Australia tjones@funnelback.com ABSTRACT Following been gathered and indexed, we build a tool for reordering an ex- isting index and show that it operates
Chen, Long-Qing
Phase-field modeling of corrosion kinetics under dual-oxidants This article has been downloaded-field modeling of corrosion kinetics under dual-oxidants You-Hai Wen1 , Long-Qing Chen2 and Jeffrey A Hawk1 1 is proposed to simulate corrosion kinetics under a dual- oxidant atmosphere. It will be demonstrated
Emission of scalar particles from cylindrical black holes
H. Gohar; K. Saifullah
2011-09-27T23:59:59.000Z
We study quantum tunneling of scalar particles from black strings. For this purpose we apply WKB approximation and Hamilton-Jacobi method to solve the Klein-Gordon equation for outgoing trajectories. We find the tunneling probability of outgoing charged and uncharged scalars from the event horizon of black strings, and hence the Hawking temperature for these black configurations.
Publications of the Hawaii Institute of Geophysics and Planetology University of Hawaii
. #12;Planet. Sci. 36, 223-230. 16. Fagan, T. J., G. J. Taylor, K. Keil, T. E. Bunch, J. H. Wittke, R. N., 28(9), 1803-1807. 3. Bell, J. W., F. Amelung, A. R. Ramelli, G. Blewitt, 2001, Land subsidence in Las. Geosy., (in press). 6. Blewett, D. T., and B. R. Hawke, 2001, Remote sensing and geological studies
Welcome Prospective Graduate Students!
in the transformative power of squeez- ing soft squishy balls. In an email statement, Sheldon says:"You underestimateWelcome Prospective Graduate Students! Inside this issue: Ken the Squirrel Killer 2 Sheldon's Balls- guests, but Ken claims it's worth it. He advises new hawkers to avoid flying their hawks near power lines
False vacuum decay in a brane world cosmological model
Michal Demetrian
2006-01-12T23:59:59.000Z
The false vacuum decay in a brane world model is studied in this work. We investigate the vacuum decay via the Coleman-de Luccia instanton, derive explicit approximative expressions for the Coleman-de Luccia instanton which is close to a Hawking-Moss instanton and compare the results with those already obtained within Einstein's theory of relativity.
The evolution of false vacuum bubbles in radiating metrics
Larsen, K.M.
1990-01-01T23:59:59.000Z
The equations of motion for false vacuum bubbles in Vaidya-Mallett metrics are derived and numerically solved. It is demonstrated that the evolution of the bubble differs from the standard Schwarzschild-de Sitter results. The luminosity as measured by an external observer is found to deviate from the normal Hawking luminosity, thus producing a signature for the existence of the child universe.
Contaminants in Fish From CaliFornia rivers
Worcester, Region 3 Water Board Michael Lyons, Region 4 Water Board Chris Foe, Region 5 Water Board Tom Suk, State Water Board Jon Marshack, State Water Board Bob Brodberg, OEHHA Tom Maurer, USFWS Jay Davis, SFEI Mundell, John Negrey Dissection: Stephen Martenuk, Kelsey James, Kim Smelker, Jenny Kemper, Heather Hawk
BULLETIN OF THE UNITED STATES FISH COMMI8SION. 111 .Nabohennd,.5usquehwna River.
. . . . . . . . . . . . . . . . . . . . . . ........................................ elace. .Nabohennd,.5usquehwna River. ...... do. ............................ .&d BankRiver .. River.. . . , ,. Red Bank,Susquoh&na Givor.. .... 36.-REPOWT ON THE SHAD WORK O F TEE STEADIEB HALOYON obtained from the U. 8.Fish Commission steamer Fish Hawk, and from Battery Station, and planted ; and 8
Single mimivirus particles intercepted and imaged with an X-ray laser (CXIDB ID 1)
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Seibert, M. Marvin; Ekeberg, Tomas; Maia, Filipe R.N.C.
These are the files used to reconstruct the images in the paper "Single Mimivirus particles intercepted and imaged with an X-ray laser". Besides the diffracted intensities, the Hawk configuration files used for the reconstructions are also provided. The files from CXIDB ID 1 are the pattern and configuration files for the pattern showed in Figure 2a in the paper.
A Song of joy: an overview of the life and work of Byron Herbert Reece
Maples, Mary Jo
1991-01-01T23:59:59.000Z
would not understand the undertone of the reference to Genesis 13:12, which reads "Abram dwelled in the land of Canaan, and Lot dwelled in the cities of the plain, and pitched his tents toward Sodom. " Recce changed the title to The Hawk and The Sun...
The Trouble with Gravity Summary/Review Lecture 7: Spring 2009 Compton Lecture Series
energy, and the mass of the black hole decreases to compensate. This is "Hawking radiation of quantum mechanics. Â· Gravity affects the vacuum energy density Â According to Newton, gravity affects anything with mass. But according to Einstein, mass is just one form of energy. It follows that gravity
Quantum corrected non-thermal radiation spectrum from the tunnelling mechanism
Subenoy Chakraborty; Subhajit Saha; Christian Corda
2015-05-28T23:59:59.000Z
Tunnelling mechanism is today considered a popular and widely used method in describing Hawking radiation. However, in relation to black hole (BH) emission, this mechanism is mostly used to obtain the Hawking temperature by comparing the probability of emission of an outgoing particle with the Boltzmann factor. On the other hand, Banerjee and Majhi reformulated the tunnelling framework deriving a black body spectrum through the density matrix for the outgoing modes for both the Bose-Einstein distribution and the Fermi-Dirac distribution. In contrast, Parikh and Wilczek introduced a correction term performing an exact calculation of the action for a tunnelling spherically symmetric particle and, as a result, the probability of emission of an outgoing particle corresponds to a non-strictly thermal radiation spectrum. Recently, one of us (C. Corda) introduced a BH effective state and was able to obtain a non-strictly black body spectrum from the tunnelling mechanism corresponding to the probability of emission of an outgoing particle found by Parikh and Wilczek. The present work introduces the quantum corrected effective temperature and the corresponding quantum corrected effective metric is written using Hawking's periodicity arguments. Thus, we obtain further corrections to the non-strictly thermal BH radiation spectrum as the final distributions take into account both the BH dynamical geometry during the emission of the particle and the quantum corrections to the semiclassical Hawking temperature.
Universal thermodynamics in different gravity theories: Modified entropy on the horizons
Saugata Mitra; Subhajit Saha; Subenoy Chakraborty
2015-03-10T23:59:59.000Z
The paper deals with universal thermodynamics for FRW model of the universe bounded by apparent (or event) horizon. Assuming Hawking temperature on the horizon, the unified first law is examined on the horizon for different gravity theories. The results show that equilibrium configuration is preserved with a modification to Bekenstein entropy on the horizon.
An increase in the magnitude of the electric charge, Q, with c and G remaining
Socha, Jake
-horizon area implies a violation of the generalized second law of thermo- dynamics, and so the fundamental the Hawking process, and, as Q changes, the temperature will also change. For the second law of thermo. Furthermore, equation (3) is based on standard gravitational theory. In a non- standard theory that involves
Alaska Nanooks Blue and Gold Game October 5, 2012 ALASKA POST
- portation and personal property. Renner,whowasnamed the supervisor of the quarter, has the number- one item. Johnson, gar- rison commander. He was talking about the civilian employee recognition program cer- emony, Lincoln Hawkes. In addition, he manages a staff of eight, rated a high- ly satisfactory on his June 2012
Frew, Eric W.
Hawk, significant effort is required to survey each airfield at which the UAS will operate, and to specify detailedAbstract--This paper presents a vision-based navigation solution for unmanned aircraft operations on airfield surfaces in GPS-denied environments. The Unmanned Aircraft System Ground Operations Management
Supersymmetric Yang Mills Fields and Black Holes ; In Ten Dimensional Unified Field Theory
Ajay Patwardhan
2007-05-17T23:59:59.000Z
The Ten dimensional Unified field theory has a 4 dimensional Riemannian spacetime and six dimensional Calabi Yau space structure. The supersymmetric Yang Mills fields and black holes are solutions in these theories. The formation of primordial black holes in early universe, the collapse to singularity of stellar black holes, the Hawking evaporation of microscopic black holes in LHC are topics of observational and theoretical interest. The observation of gamma ray bursts and creation of spectrum of particles and radiation of dark and normal matter occur due to primordial and microscopic black holes. The approach to singularity in black hole interior solutions, require the Bogoliubov transforms of SUSY YM fields in black hole geometries; both during formation and in evaporation. The Hawking effect of radiating black holes is applicable for all the fields. Invariants can be defined to give the conditions for these processes.
Quantum Emission from Two-Dimensional Black Holes
Steven B. Giddings; W. M. Nelson
2009-11-27T23:59:59.000Z
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.
Inflation with a Planck-scale frequency cutoff
J. C. Niemeyer
2000-11-22T23:59:59.000Z
The implementation of a Planck-scale high frequency and short wavelength cutoff in quantum theories on expanding backgrounds may have potentially nontrivial implications, such as the breaking of local Lorentz invariance and the existence of a yet unknown mechanism for the creation of vacuum modes. In scenarios where inflation begins close to the cutoff scale, these effects could have observable consequences as trans-Planckian modes are redshifted to cosmological scales. In close analogy with similar studies of Hawking radiation, a simple theory of a minimally coupled scalar field in de Sitter space is studied, with a high frequency cutoff imposed by a nonlinear dispersion relation. Under certain conditions the model predicts deviations from the standard inflationary scenario. We also comment on the difficulties in generalizing fluid models of Hawking radiation to cosmological space-times.
Evolution of Primordial Black Holes in a radiation and phantom energy environment
Daniel C. Guariento; J. E. Horvath; P. S. Custódio; J. A. de Freitas Pacheco
2007-11-22T23:59:59.000Z
In this work we extend previous work on the evolution of a Primordial Black Hole (PBH) to address the presence of a dark energy component with a super-negative equation of state as a background, investigating the competition between the radiation accretion, the Hawking evaporation and the phantom accretion, the latter two causing a decrease on black hole mass. It is found that there is an instant during the matter-dominated era after which the radiation accretion becomes negligible compared to the phantom accretion. The Hawking evaporation may become important again depending on a mass threshold. The evaporation of PBHs is quite modified at late times by these effects, but only if the Generalized Second Law of thermodynamics is violated.
QCD thermodynamics using five-dimensional gravity
Megias, E.; Veschgini, K. [Institute for Theoretical Physics, University of Heidelberg (Germany); Pirner, H. J. [Institute for Theoretical Physics, University of Heidelberg (Germany); Max Planck Institute for Nuclear Physics, Heidelberg (Germany)
2011-03-01T23:59:59.000Z
We calculate the critical temperature and free energy of the gluon plasma using the dilaton potential [B. Galow, E. Megias, J. Nian, and H. J. Pirner, Nucl. Phys. B834, 330 (2010).] in the gravity theory of anti-de Sitter/QCD. The finite temperature observables are calculated in two ways: first, from the Page-Hawking computation of the free energy, and secondly using the Bekenstein-Hawking proportionality of the entropy with the area of the horizon. Renormalization is well defined, because the T=0 theory has asymptotic freedom. We further investigate the change of the critical temperature with the number of flavors induced by the change of the running coupling constant in the quenched theory. The finite temperature behavior of the speed of sound, spatial string tension and vacuum expectation value of the Polyakov loop follow from the corresponding string theory in AdS{sub 5}.
Black hole evaporation in a noncommutative charged Vaidya model
Sharif, M., E-mail: msharif.math@pu.edu.pk; Javed, W. [University of the Punjab, Department of Mathematics (Pakistan)
2012-06-15T23:59:59.000Z
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstroem-like solution of this model, which leads to an exact (t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Tensile Strength and the Mining of Black Holes
Adam R. Brown
2012-07-13T23:59:59.000Z
There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This paper looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta and puts a severe constraint on the operation of 'space elevators' near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed and that as a consequence of this limitation the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings.
The Vernacular Watercraft of Isle Royale: a western Lake Superior boatbuilding tradition
Tolson, Hawk
1992-01-01T23:59:59.000Z
. L. Hamilton (Member) Michael R. Waters (Member) aughn M. Bryant, (Head of Department) August 1992 ABSTRACT The Vernacular Watercraft of Isle Royale: A Western Lake Superior Boatbuilding Tradition. (August 1992) Hawk Toison, B. Sc... their scheduled work runs around the Island. In Washington Harbor, Stanley Sivertson allowed me the use of one of his cabins for the month and a half that I was there, and patiently endured my crawling over, under, around, and through his gas boat SIVIE...
Imaging single cells in a beam of live cyanobacteria with an X-ray laser
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Schot, Gijs, vander
This entry contains ten diffraction patterns, and reconstructions images, of individual living Cyanobium gracile cells, imaged using 517 eV X-rays from the LCLS XFEL. The Hawk software package was used for phasing. The Uppsala aerosol injector was used for sample injection, assuring very low noise levels. The cells come from various stages of the cell cycle, and were imaged in random orientations.
Can an evolving Universe host a static event horizon?
Aharon Davidson; Shimon Rubin; Yosef Verbin
2012-11-09T23:59:59.000Z
We prove the existence of general relativistic perfect fluid black hole solutions, and demonstrate the phenomenon for the $P=w\\rho$ class of equations of state. While admitting a local time-like Killing vector on the event horizon itself, the various black hole configurations are necessarily time dependent (thereby avoiding a well known no-go theorem) away from the horizon. Consistently, Hawking's imaginary time periodicity is globally manifest on the entire spacetime manifold.
Black Hole Radiation On and Off the Brane
Roberto Emparan
2000-09-26T23:59:59.000Z
After a brief review of the description of black holes on branes, we examine the evaporation of a small black hole on a brane in a world with large extra dimensions. We show that, contrary to previous claims, most of the energy is radiated into the modes on the brane. This raises the possibility of observing Hawking radiation in future high energy colliders if there are large extra dimensions.
The Smart Grid, A Scale Demonstration Model Incorporating Electrified Vehicles
Clemon, Lee; Mattson, Jon; Moore, Andrew; Necefer, Len; Heilman, Shelton
2011-04-01T23:59:59.000Z
energy infrastructure. Furthermore, with the advent and commercialization of electrified vehicles, energy demand has the capability to increase dramatically. A sustainable solution via renewable energy technologies can act to offset... to ensure the energy security of the United States. Supported by the EPA P3 initiative, the current small-scale stage of the EcoHawks design project involves creation of a smart energy infrastructure that integrates solar and wind renewable energy...
4500. Nasch, P.M., M.H. Manghnani, and R.A. Secco, 1997, Anomalous behavior of sound velocityForschungsZentrum, Potsdam, Germany, 6-16. 4502. Blewett, D.T., P.G. Lucey, and B.R. Hawke, 1997, Clementine images., 132, 119-132. 4504. Yu, Z.-P., P.-S. Chu, and T. Schroeder, 1997, Predictive skills of seasonal
Thermodynamical instability of black holes
V. V. Kiselev
2012-08-07T23:59:59.000Z
In contrast to Hawking radiation of black hole with a given spacetime structure, we consider a competitive transition due to a heat transfer from a hotter inner horizon to a colder outer horizon of Kerr black hole, that results in a stable thermodynamical state of extremal black hole. In this process, by supposing an emission of gravitational quanta, we calculate the mass of extremal black hole in the final state of transition.
On the Quantum-Corrected Black Hole Thermodynamics
Kourosh Nozari; S. Hamid Mehdipour
2006-01-15T23:59:59.000Z
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.
Entropy of charged dilaton-axion black hole
Tanwi Ghosh; Soumitra SenGupta
2008-06-06T23:59:59.000Z
Using brick wall method the entropy of charged dilaton-axion black hole is determined for both asymptotically flat and non-flat cases. The entropy turns out to be proportional to the horizon area of the black hole confirming the Beckenstien, Hawking area-entropy formula for black holes. The leading order logarithmic corrections to the entropy are also derived for such black holes.
Investigating the Use of Destination Math in an Urban School District
Telford, William David
2011-10-21T23:59:59.000Z
scores (McNabb, Hawkes, & Rouk, 1999). The impact of these expenditures required study. Simkins (2006) indicated that program evaluation must answer three questions: ?How does the technology add value? How will you know the technology is working..., such as three-dimensional imaging, to become a part of instruction (Blystone, 1998). Mathematic concepts could be modeled with emerging software (Trotter, 2007b). Simkins (2006) asserted that utilizing technology could increase the depth of learning...
False vacuum decay with gravity in a critical case
Michal Demetrian
2005-05-17T23:59:59.000Z
The vacuum decay in a de Sitter universe is studied within semiclassical approximation for the class of effective inflaton potentials whose curvature at the top is close to a critical value. By comparing the actions of the Hawking - Moss instanton and the Coleman - de Luccia instanton(s) the mode of vacuum decay is determined. The case when the fourth derivative of the effective potential at its top is less than a critical value is discussed.
An experimental and theoretical acoustic investigation of single disc propellers
Bumann, Elizabeth Ann
1988-01-01T23:59:59.000Z
performance strip analysis which utilized a NACA 4-digit series airfoil data bank to calculate the lift and drag for each blade segment given the shape and motion of the propeller. A RPM range between 3500 and 7000 RPM in 250 increments was used for each... ACOUSTIC PREDICTION TECHNIQUES . . 4 Gutin Garrick and Watkins Lighthill's Acoustic Analogy Ffowcs - Williams and Hawkings Farassat Ha. nson Woan and Gregorek . 8 10 11 III ACOUSTIC COMPACT SOURCE THEOR'I Blade Element Theory Acoustic...
Towards noncommutative quantum black holes
Lopez-Dominguez, J. C.; Obregon, O.; Sabido, M.; Ramirez, C. [Instituto de Fisica de la Universidad de Guanajuato, P.O. Box E-143, 37150 Leon Gto. (Mexico); Facultad de Ciencias Fisico Matematicas, Universidad Autonoma de Puebla, P.O. Box 1364, 72000 Puebla (Mexico)
2006-10-15T23:59:59.000Z
In this paper we study noncommutative black holes. We use a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.
On the Architecture of Spacetime Geometry
Eugenio Bianchi; Robert C. Myers
2012-12-20T23:59:59.000Z
We propose entanglement entropy as a probe of the architecture of spacetime in quantum gravity. We argue that the leading contribution to this entropy satisfies an area law for any sufficiently large region in a smooth spacetime, which, in fact, is given by the Bekenstein-Hawking formula. This conjecture is supported by various lines of evidence from perturbative quantum gravity, simplified models of induced gravity and loop quantum gravity, as well as the AdS/CFT correspondence.
Notes on Black Hole Fluctuations and Backreaction
B. L. Hu; Alpan Raval; Sukanya Sinha
1999-01-05T23:59:59.000Z
In these notes we prepare the ground for a systematic investigation into the issues of black hole fluctuations and backreaction by discussing the formulation of the problem, commenting on possible advantages and shortcomings of existing works, and introducing our own approach via a stochastic semiclassical theory of gravity based on the Einstein-Langevin equation and the fluctuation-dissipation relation for a self-consistent description of metric fluctuations and dissipative dynamics of the black hole with backreaction of its Hawking radiance.
Black hole radiation of spin-1 particles in (1+2) dimensions
S. I. Kruglov
2014-11-26T23:59:59.000Z
The radiation of vector particles by black holes in (1+2) dimensions is investigated within the WKB approximation. We consider the process of quantum tunnelling of bosons through an event horizon of the black hole. The emission temperature for the Schwarzschild background geometry coincides with the Hawking temperature and for the Rindler spacetime the temperature is the Unruh temperature. We also obtain the radiation temperatures for the de Sitter spacetime.
Sarah L. Gamage | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative JC3 RSS September 9,AwardGrads & Researchers STEMSarah EchoHawk About Us
Saving Electricity | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative JC3 RSS September 9,AwardGrads & Researchers STEMSarah EchoHawk About
Savings Project: Install Exterior Storm Windows With Low-E Coating |
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative JC3 RSS September 9,AwardGrads & Researchers STEMSarah EchoHawk
Schedules of Key Environmental Impact Statements | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative JC3 RSS September 9,AwardGrads & Researchers STEMSarah EchoHawkSavings
Schneider Electric Director Initiates Strategy to Recruit IAC Graduates |
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative JC3 RSS September 9,AwardGrads & Researchers STEMSarah EchoHawkSavingsDepartment
Quantum vacuum radiation in optical glass
Stefano Liberati; Angus Prain; Matt Visser
2011-11-01T23:59:59.000Z
A recent experimental claim of the detection of analogue Hawking radiation in an optical system [PRL 105 (2010) 203901] has led to some controversy [PRL 107 (2011) 149401, 149402]. While this experiment strongly suggests some form of particle creation from the quantum vacuum (and hence it is per se very interesting), it is also true that it seems difficult to completely explain all features of the observations by adopting the perspective of a Hawking-like mechanism for the radiation. For instance, the observed photons are emitted parallel to the optical horizon, and the relevant optical horizon is itself defined in an unusual manner by combining group and phase velocities. This raises the question: Is this really Hawking radiation, or some other form of quantum vacuum radiation? Naive estimates of the amount of quantum vacuum radiation generated due to the rapidly changing refractive index --- sometimes called the dynamical Casimir effect --- are not encouraging. However we feel that naive estimates could be misleading depending on the quantitative magnitude of two specific physical effects: "pulse steepening" and "pulse cresting". Plausible bounds on the maximum size of these two effects results in estimates much closer to the experimental observations, and we argue that the dynamical Casimir effect is now worth additional investigation.
NSTX-U Control System Upgrades
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Erickson, K G; Gates, D A; Gerhardt, S P; Lawson, J E; Mozulay, R; Sichta, P; Tchilinguirian, G J
2014-06-01T23:59:59.000Z
The National Spherical Tokamak Experiment (NSTX) is undergoing a wealth of upgrades (NSTX-U). These upgrades, especially including an elongated pulse length, require broad changes to the control system that has served NSTX well. A new fiber serial Front Panel Data Port input and output (I/O) stream will supersede the aging copper parallel version. Driver support for the new I/O and cyber security concerns require updating the operating system from Redhat Enterprise Linux (RHEL) v4 to RedHawk (based on RHEL) v6. While the basic control system continues to use the General Atomics Plasma Control System (GA PCS), the effort to forward port the entire software package to run under 64-bit Linux instead of 32-bit Linux included PCS modifications subsequently shared with GA and other PCS users. Software updates focused on three key areas: (1) code modernization through coding standards (C99/C11), (2) code portability and maintainability through use of the GA PCS code generator, and (3) support of 64-bit platforms. Central to the control system upgrade is the use of a complete real time (RT) Linux platform provided by Concurrent Computer Corporation, consisting of a computer (iHawk), an operating system and drivers (RedHawk), and RT tools (NightStar). Strong vendor support coupled with an extensive RT toolset influenced this decision. The new real-time Linux platform, I/O, and software engineering will foster enhanced capability and performance for NSTX-U plasma control.
Quantum-mechanical nonequivalence of metrics of centrally symmetric uncharged gravitational field
M. V. Gorbatenko; V. P. Neznamov
2013-08-02T23:59:59.000Z
Quantum-mechanical analysis shows that the metrics of a centrally symmetric uncharged gravitational field, which are exact solutions of the general relativity equations, are physically non-equivalent. The classical Schwarzschield metric and the Schwarzschild metrics in isotropic and harmonic coordinates provide for the existence of stationary bound states of Dirac particles with a real energy spectrum. The Hilbert condition g_{00}>0 is responsible for zero values of the wave functions under the "event horizon" that leads to the absence of Hawking radiation. For the Eddington-Finkelstein and Painleve-Gullstrand metrics, stationary bound states of spin-half particles cannot exist because Dirac Hamiltonians are non-Hermitian. For these metrics, the condition g_{00}>0 also leads to the absence of Hawking evaporation. For the Finkelstein-Lemaitre and Kruskal metrics, Dirac Hamiltonians are explicitly time-dependent, and stationary bound states of spin-half particles cannot exist for them. The Hilbert condition for these metrics does not place any constraints on the domains of the wave functions. Hawking evaporation of black holes is possible in this case. The results can lead to revisiting some concepts of the standard cosmological model related to the evolution of the universe and interaction of collapsars with surrounding matter.
Uncertainty relation in Schwarzschild spacetime
Jun Feng; Yao-Zhong Zhang; Mark D. Gould; Heng Fan
2015-02-27T23:59:59.000Z
We explore the entropic uncertainty relation in the curved background outside a Schwarzschild black hole, and find that Hawking radiation introduces a nontrivial modification on the uncertainty bound for particular observer, therefore it could be witnessed by proper uncertainty game experimentally. We first investigate an uncertainty game between a free falling observer and his static partner holding a quantum memory initially entangled with the quantum system to be measured. Due to the information loss from Hawking decoherence, we find an inevitable increase of the uncertainty on the outcome of measurements in the view of static observer, which is dependent on the mass of the black hole, the distance of observer from event horizon, and the mode frequency of quantum memory. To illustrate the generality of this paradigm, we relate the entropic uncertainty bound with other uncertainty probe, e.g., time-energy uncertainty. In an alternative game between two static players, we show that quantum information of qubit can be transferred to quantum memory through a bath of fluctuating quantum fields outside the black hole. For a particular choice of initial state, we show that the Hawking decoherence cannot counteract entanglement generation after the dynamical evolution of system, which triggers an effectively reduced uncertainty bound that violates the intrinsic limit $-\\log_2c$. Numerically estimation for a proper choice of initial state shows that our result is comparable with possible real experiments. Finally, a discussion on the black hole firewall paradox in the context of entropic uncertainty relation is given.
Revisit emission spectrum and entropy quantum of the Reissner-Nordström black hole
Qing-Quan Jiang
2012-10-15T23:59:59.000Z
Banerjee and Majhi's recent work shows that black hole's emission spectrum could be fully reproduced in the tunneling picture, where, as an intriguing technique, the Kruskal extension was introduced to connect the left and right modes inside and outside the horizon. Some attempt, as an extension, was focused on producing the Hawking emission spectrum of the (charged) Reissner-Nordstr\\"{o}m black hole in the Banerjee-Majhi's treatment. Unfortunately, the Kruskal extension in their observation was so badly defined that the ingoing mode was classically forbidden traveling towards the center of black hole, but could quantum tunnel across the horizon with the probability $\\Gamma=e^{-\\pi \\omega_0/\\kappa_+}$. This tunneling picture is unphysical. With this point as a central motivation, in this paper we first introduce such a suitable Kruskal extension for the (charged) Reissner-Nordstr\\"{o}m black hole that a perfect tunneling picture can be provided during the charged particle's emission. Then, under the new Kruskal extension, we revisit the Hawking emission spectrum and entropy spectroscopy as tunneling from the charged black hole. The result shows that the tunneling method is so universally robust that the Hawking blackbody emission spectrum from a charged black hole can be well reproduced in the tunneling mechanism, and its induced entropy quantum is a much better approximation for the forthcoming quantum gravity theory.
Black Hole Remnants and the Information Loss Paradox
Pisin Chen; Yen Chin Ong; Dong-han Yeom
2015-01-30T23:59:59.000Z
Forty years after the discovery of Hawking radiation, its exact nature remains elusive. If Hawking radiation does not carry any information out from the ever shrinking black hole, it seems that unitarity is violated once the black hole completely evaporates. On the other hand, attempts to recover information via quantum entanglement lead to the firewall controversy. Amid the confusions, the possibility that black hole evaporation stops with a "remnant" has remained unpopular and is often dismissed due to some "undesired properties" of such an object. Nevertheless, as in any scientific debate, the pros and cons of any proposal must be carefully scrutinized. We fill in the void of the literature by providing a timely review of various types of black hole remnants, and provide some new thoughts regarding the challenges that black hole remnants face in the context of information loss paradox and its latest incarnation, namely the firewall controversy. The importance of understanding the role of curvature singularity is also emphasized, after all there remains a possibility that singularity cannot be cured even by quantum gravity. In this context a black hole remnant conveniently serves as a cosmic censor. We conclude that a remnant remains a possible end state of Hawking evaporation, and if it contains large interior geometry, may help to ameliorate information loss and the firewall paradox. We hope that this will raise some interests in the community to investigate remnants more critically but also more thoroughly.
Falling through the black hole horizon
Brustein, Ram
2015-01-01T23:59:59.000Z
We consider the fate of a small classical object, a "stick", as it falls through the horizon of a large black hole (BH). Classically, the equivalence principle dictates that the stick is affected by small tidal forces, and Hawking's quantum-mechanical model of BH evaporation makes essentially the same prediction. If, on the other hand, the BH horizon is surrounded by a "firewall", the stick will be consumed as it falls through. We have recently extended Hawking's model by taking into account the quantum fluctuations of the geometry and the classical back-reaction of the emitted particles. Here, we calculate the strain exerted on the falling stick for our model. The strain depends on the near-horizon state of the Hawking pairs. We find that, after the Page time when the state of the pairs deviates significantly from maximal entanglement (as required by unitarity), the induced strain in our semiclassical model is still parametrically small. This is because the number of the disentangled pairs is parametrically ...
NSTX-U Control System Upgrades
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Erickson, K. G.; Gates, D. A.; Gerhardt, S. P.; Lawson, J. E.; Mozulay, R.; Sichta, P.; Tchilinguirian, G. J.
2014-06-01T23:59:59.000Z
The National Spherical Tokamak Experiment (NSTX) is undergoing a wealth of upgrades (NSTX-U). These upgrades, especially including an elongated pulse length, require broad changes to the control system that has served NSTX well. A new fiber serial Front Panel Data Port input and output (I/O) stream will supersede the aging copper parallel version. Driver support for the new I/O and cyber security concerns require updating the operating system from Redhat Enterprise Linux (RHEL) v4 to RedHawk (based on RHEL) v6. While the basic control system continues to use the General Atomics Plasma Control System (GA PCS), the effort to forwardmore »port the entire software package to run under 64-bit Linux instead of 32-bit Linux included PCS modifications subsequently shared with GA and other PCS users. Software updates focused on three key areas: (1) code modernization through coding standards (C99/C11), (2) code portability and maintainability through use of the GA PCS code generator, and (3) support of 64-bit platforms. Central to the control system upgrade is the use of a complete real time (RT) Linux platform provided by Concurrent Computer Corporation, consisting of a computer (iHawk), an operating system and drivers (RedHawk), and RT tools (NightStar). Strong vendor support coupled with an extensive RT toolset influenced this decision. The new real-time Linux platform, I/O, and software engineering will foster enhanced capability and performance for NSTX-U plasma control.« less
Microscopic quantum structure of black hole and vacuum versus quantum statistical origin of gravity
Shun-Jin Wang
2014-10-28T23:59:59.000Z
The Planckon densely piled model of vacuum is proposed. Based on this model, the microscopic quantum structure of Schwarzschild black hole and quantum statistical origin of its gravity are studied. The cutoff of black hole horizon leads to Casimir effect inside the horizon. This effect makes the inside vacuum has less zero quantum fluctuation energy than that of outside vacuum and the spin 1/2 radiation hole excitations are resulted inside the horizon. The mean energy of the radiation hole excitations is related to the temperature decrease of the Hawking-Unruh type by the period law of the Fermion temperature greens function and a temperature difference as well as gravity are created on the horizon. A dual relation of the gravity potentials between inside and outside regions of the black hole is found. An attractor behaviour of the horizon surface is unveiled. The gravity potential inside the black hole is linear in radial coordinate and no singularity exists at the origin of the black hole, in contrast to the conventional conjecture. All the particles absorbed by the black hole have fallen down to the horizon and converted into spin 1/2 radiation quanta with the mean energy related to the Hawking-Unruh temperature, the thermodynamic equilibrium and the mechanical balance make the radiation quanta be tightly bound in the horizon. The gravitation mass $2M$ and physical mass $M$ of the black hole are calculated. The calculated entropy of the black hole is well consistent with Hawking. Outside the horizon, there exist thermodynamic non-equilibrium and mechanical non-balance which lead to an outward centrifugal energy flow and an inward gravitation energy flow. The lost vacuum energy in the negative gravitation potential region has been removed to the black hole surface to form a spherical Planckon shell with the thickness of Planckon diameter so that energy conservation is guaranteed.
Density matrix of black hole radiation
Lasma Alberte; Ram Brustein; Andrei Khmelnitsky; A. J. M. Medved
2015-02-09T23:59:59.000Z
Hawking's model of black hole evaporation is not unitary and leads to a mixed density matrix for the emitted radiation, while the Page model describes a unitary evaporation process in which the density matrix evolves from an almost thermal state to a pure state. We compare a recently proposed model of semiclassical black hole evaporation to the two established models. In particular, we study the density matrix of the outgoing radiation and determine how the magnitude of the off-diagonal corrections differs for the three frameworks. For Hawking's model, we find power-law corrections to the two-point functions that induce exponentially suppressed corrections to the off-diagonal elements of the full density matrix. This verifies that the Hawking result is correct to all orders in perturbation theory and also allows one to express the full density matrix in terms of the single-particle density matrix. We then consider the semiclassical theory for which the corrections, being non-perturbative from an effective field-theory perspective, are much less suppressed and grow monotonically in time. In this case, the R\\'enyi entropy for the outgoing radiation is shown to grow linearly at early times; but this growth slows down and the entropy eventually starts to decrease at the Page time. In addition to comparing models, we emphasize the distinction between the state of the radiation emitted from a black hole, which is highly quantum, and that of the radiation emitted from a typical classical black body at the same temperature.
1994 Northern Goshawk inventory on portions of Los Alamos National Laboratory, Los Alamos, NM
Sinton, D.T.; Kennedy, P.L. [Colorado State Univ., Fort Collins, CO (United States)
1995-01-01T23:59:59.000Z
Northern goshawks (Accipiter gentilis) (hereafter referred to as goshawk) are large forest dwelling hawks. They are the largest species of the Accipiter genus which also includes sharp-shinned hawks (A. striatus) and the Cooper`s hawk (A. cooperii). Goshawks are holarctic in distribution and nest in coniferous, deciduous, and mixed species forests. In the southwest they primarily nest in ponderosa pine (Pinus ponderosa), mixed species, and spruce-fir forests. Goshawks may be declining in population and reproduction in the southwestern United States. In 1982 the USDA-Forest Service listed the goshawk as a {open_quotes}sensitive species{close_quotes} and in 1992 the U.S. Fish and Wildlife Service listed the goshawk as a {open_quotes}Category 2 species{close_quotes} in accordance with the Endangered Species Act. Reasons for the possible decline in goshawk populations include timber harvesting resulting in the loss of nesting habitat, toxic chemicals, and the effects of drought, fire, and disease. Thus, there is a need to determine their population status and assess impacts of management activities in potential goshawk habitat. Goshawk inventory was conducted during the 1993 nesting season with no adult goshawk responses detected within the LANL survey area. As noted by Sinton and Kennedy, these results may be interpreted in several ways: (1) no goshawk territory(ies) occur in the inventoried area; (2) goshawk territory(ies) exist but have failed prior to the survey and thus were not detected; or (3) territory(ies) exist and were successful but the goshawks did not respond to tapes or their responses were undetected by the observer. For those reasons, a goshawk inventory was conducted in 1994. This report summarizes the results of this inventory.
CHARYBDIS: A Black hole event generator.
Harris, Chris M; Richardson, P; Webber, Bryan R
Gauss’ Law, that for r ? R then V (r) ? M Mn+2p 1 rn+1 , (2.1) whereas for r ? R V (r) ? M Mn+2p Rn 1 r . (2.2) In these expressions Mp is the (4+n)-dimensional Planck mass (throughout this paper the conventions of [8] are used for Mp). They show... been shown in [17] that the majority of energy in Hawking radiation is emitted into modes on the brane (i.e. as Standard Model particles) but a small amount is also emitted into modes in the bulk (i.e. as gravitons). In 4D the phase which accounts...
Houze, Robert Alvin
1969-01-01T23:59:59.000Z
. Hawkes (Boston: Houghton-Mifflin Company, 1966), p. 21. infinite graduation of social advantage-disadvantage, but that he would place it at 15 per cent. Since these children tend to concen- trate in urban areas, the figure could be as high as 30 per... in locating materials for purposes of inter-library loan, or for possible on-site use of resources. Other data concern- ing audiovisual materials, media laboratories and equipment were to be elicited as additional helpful information. g Questionnaires were...
The use of oxytocin and progestins to induce and synchronize estrus in beef cattle
Keisler, Duane Harold
1979-01-01T23:59:59.000Z
, 1970; Abkar et al. , 1970; Piper and Foote, 1970; Hawk and Bolt, 1970; Denamur and Kann, 1973; Kittok and Britt, 1977). Similar findings are reported in the bovine, but the effects are not as complete (Wi ltbank, 1966; Wi ltbank et al. , 1961... of the CL well beyond the usual time of luteal regression (Piper and Foote, 1965, 1968, 1970; Denamur et al. , 1970). These findings as well as indirect investigations into estrogens ovar- ian vascular responses in the ovine (Niswender et al. , 1976...
Ergoregion instability: The hydrodynamic vortex
Leandro A. Oliveira; Vitor Cardoso; Luís C. B. Crispino
2014-05-16T23:59:59.000Z
Four-dimensional, asymptotically flat spacetimes with an ergoregion but no horizon have been shown to be linearly unstable against a superradiant-triggered mechanism. This result has wide implications in the search for astrophysically viable alternatives to black holes, but also in the understanding of black holes and Hawking evaporation. Here we investigate this instability in detail for a particular setup which can be realized in the laboratory: the {\\it hydrodynamic vortex}, an effective geometry for sound waves, with ergoregion and without an event horizon.
Spectral Lags of Gamma-Ray Bursts from Primordial Black Hole (PBH) Evaporations
T. N. Ukwatta; J. H. MacGibbon; W. C. Parke; K. S. Dhuga; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris
2009-08-14T23:59:59.000Z
Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. PBHs with an initial mass of 5.0 * 10^14 g should be expiring today with a burst of high energy particles. Evaporating PBHs in the solar neighborhood are candidate Gamma-Ray Bursts (GRBs) progenitors. We propose spectral lag, which is the temporal delay between the high energy photon pulse and the low energy photon pulse, as a possible method to detect PBH evaporation events with the Fermi Gamma-ray Space Telescope Observatory.
S. W. Allendorf; B. W. Bellow; R. f. Boehm
2000-05-01T23:59:59.000Z
Three low-pressure rocket motor propellant burn tests were performed in a large, sealed test chamber located at the X-tunnel complex on the Department of Energy's Nevada Test Site in the period May--June 1997. NIKE rocket motors containing double base propellant were used in two tests (two and four motors, respectively), and the third test used two improved HAWK rocket motors containing composite propellant. The preliminary containment safety calculations, the crack and burn procedures used in each test, and the results of various measurements made during and after each test are all summarized and collected in this document.
Upper bound for entropy in asymptotically de Sitter space-time
Kengo Maeda; Tatsuhiko Koike; Makoto Narita; Akihiro Ishibashi
1997-12-05T23:59:59.000Z
We investigate nature of asymptotically de Sitter space-times containing a black hole. We show that if the matter fields satisfy the dominant energy condition and the cosmic censorship holds in the considering space-time, the area of the cosmological event horizon for an observer approaching a future timelike infinity does not decrease, i.e. the second law is satisfied. We also show under the same conditions that the total area of the black hole and the cosmological event horizon, a quarter of which is the total Bekenstein-Hawking entropy, is less than $12\\pi/\\Lambda$, where $\\Lambda$ is a cosmological constant. Physical implications are also discussed.
The second law of blackhole dynamics
Koustubh Ajit Kabe
2010-03-08T23:59:59.000Z
In this paper, the non-generalized or restricted second law blackhole dynamics as given by Bekenstein in the beginning is restated, with a rigid proof, in a different form akin to the statement of the second law of thermodynamics given by Clausius. The various physical possibilities and implications of this statement are discussed therein. This paper is a mere venture into the restricted second law of blackhole dynamics pertaining to blackholes emitting Hawking radiation. The paper thus considers a didactically interesting reformulation of the second law of blackhole thermodynamics after some revisions.
Black Hole Radiation and Volume Statistical Entropy
Mario Rabinowitz
2005-06-29T23:59:59.000Z
The simplest possible equation for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius which is similar to the Compton wavelength relation.
Quantum Cooling Evaporation Process in Regular Black Holes
Yun Soo Myung; Yong-Wan Kim; Young-Jai Park
2007-09-28T23:59:59.000Z
We investigate a universal behavior of thermodynamics and evaporation process for the regular black holes. We newly observe an important point where the temperature is maximum, the heat capacity is changed from negative infinity to positive infinity, and the free energy is minimum. Furthermore, this point separates the evaporation process into the early stage with negative heat capacity and the late stage with positive heat capacity. The latter represents the quantum cooling evaporation process. As a result, the whole evaporation process could be regarded as the inverse Hawking-Page phase transition.
Fiber-optical analogue of the event horizon
Thomas G. Philbin; Chris Kuklewicz; Scott Robertson; Stephen Hill; Friedrich Konig; Ulf Leonhardt
2008-02-13T23:59:59.000Z
The physics at the event horizon resembles the behavior of waves in moving media. Horizons are formed where the local speed of the medium exceeds the wave velocity. We use ultrashort pulses in microstructured optical fibers to demonstrate the formation of an artificial event horizon in optics. We observed a classical optical effect, the blue-shifting of light at a white-hole horizon. We also show by theoretical calculations that such a system is capable of probing the quantum effects of horizons, in particular Hawking radiation.
A Compressed Air Reduction Program
Hawks, K. D.
A COMPRESSED AIR REDUCTION PROGRAM K. Dwight Hawks General Motors Corporation - Ruick-Oldsmobi1e-Cadillac Group Warren, Michigan ABSTRACT The reascn for implementing this program was to assist the plant in Quantifying some of its leaks... in the equipme~t throuqhout the plant and to provide direction as to which leaks are yenerat~ng high uti 1ity costs. The direction is very beneficial in lIlaking maintenance aware of prolill,Pls within equipment .IS \\Iell as notifying them as to whf're thei...
A Study of Universal Thermodynamics in Brane World Scenario
Saugata Mitra; Subhajit Saha; Subenoy Chakraborty
2015-03-25T23:59:59.000Z
A study of Universal thermodynamics is done in the frame work of RSII brane model and DGP brane scenario. The Universe is chosen as FRW model bounded by apparent or event horizon. Assuming extended Hawking temperature on the horizon, the unified first law is examined for perfect fluid (with constant equation of state) and modified Chaplygin gas model. As a result there is a modification of Bekenstein entropy on the horizons. Further the validity of the generalized second law of thermodynamics and thermodynamical equilibrium are also investigated.
A Study of Universal Thermodynamics in Brane World Scenario
Mitra, Saugata; Chakraborty, Subenoy
2015-01-01T23:59:59.000Z
A study of Universal thermodynamics is done in the frame work of RSII brane model and DGP brane scenario. The Universe is chosen as FRW model bounded by apparent or event horizon. Assuming extended Hawking temperature on the horizon, the unified first law is examined for perfect fluid (with constant equation of state) and modified Chaplygin gas model. As a result there is a modification of Bekenstein entropy on the horizons. Further the validity of the generalized second law of thermodynamics and thermodynamical equilibrium are also investigated.
None
2009-09-09T23:59:59.000Z
Gravity and quantum theory cause the Universe to be spontaneously created out of nothing. Most of these universes are quite unlike our own but we select out a subset that are compatible with what we observe. Please note that Professor Hawking's talk will be broadcasted in the following rooms : TH auditorium (4-3-006) TE auditorium (30-7-018) 40-S2-A01 40-S2-C01 BE Meyrin (6-2-024) BE Prévessin (864-1-D02)
Phase transition between non-extremal and extremal Reissner-Nordström black holes
Yun Soo Myung
2008-03-11T23:59:59.000Z
We discuss the phase transition between non-extremal and extremal Reissner-Nordstr\\"om black holes. This transition is considered as the $T \\to 0$ limit of the transition between the non-extremal and near-extremal black holes. We show that an evaporating process from non-extremal black hole to extremal one is possible to occur, but its reverse process is not possible to occur because of the presence of the maximum temperature. Furthermore, it is shown that the Hawking-Page phase transition between small and large black holes unlikely occurs in the AdS Reissner-Nordstr\\"om black holes.
None
2011-10-06T23:59:59.000Z
Gravity and quantum theory cause the Universe to be spontaneously created out of nothing. Most of these universes are quite unlike our own but we select out a subset that are compatible with what we observe. Please note that Professor Hawking's talk will be broadcasted in the following rooms : TH auditorium (4-3-006) TE auditorium (30-7-018) 40-S2-A01 40-S2-C01 BE Meyrin (6-2-024) BE Prévessin (864-1-D02)
On Thermodynamics of 2d Black Holes in Brane Inflationary Potentials
A. Belhaj; M. Chabab; H. El Moumni; M. B. Sedra; A. Segui
2014-01-29T23:59:59.000Z
Inspired from the inflation brane world cosmology, we study the thermodynamics of a black hole solution in two dimensional dilaton gravity with an arctangent potential background. We first derive the two dimensional black hole geometry, then we examine its asymptotic behaviors. More precisely, we find that such behaviors exhibit properties appearing in some known cases including the Anti de Sitter and the Schwarzchild black holes. Using the complex path method, we compute the Hawking radiation. The entropy function can be related to the value of the potential at the horizon.
Black hole temperature: Minimal coupling vs conformal coupling
Fazel, Mohamadreza, E-mail: m.fazel@ph.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Department of Physics, University of Tehran, North Kargar Avenue, Teharn 14395-547 (Iran, Islamic Republic of); Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mansoori, Seyed Ali Hosseini, E-mail: sa.hosseinimansoori@ph.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)
2014-05-15T23:59:59.000Z
In this article, we discuss the propagation of scalar fields in conformally transformed spacetimes with either minimal or conformal coupling. The conformally coupled equation of motion is transformed into a one-dimensional Schrödinger-like equation with an invariant potential under conformal transformation. In a second stage, we argue that calculations based on conformal coupling yield the same Hawking temperature as those based on minimal coupling. Finally, it is conjectured that the quasi normal modes of black holes are invariant under conformal transformation.
Introduction to Black Hole Evaporation
Pierre-Henry Lambert
2014-01-16T23:59:59.000Z
These lecture notes are an elementary and pedagogical introduction to the black hole evaporation, based on a lecture given by the author at the Ninth Modave Summer School in Mathematical Physics and are intended for PhD students. First, quantum field theory in curved spacetime is studied and tools needed for the remaining of the course are introduced. Then, quantum field theory in Rindler spacetime in 1+1 dimensions and in the spacetime of a spherically collapsing star are considered, leading to Unruh and Hawking effects, respectively. Finally, some consequences such as thermodynamics of black holes and information loss paradox are discussed.
Schwarzschild-like metric and a quantum vacuum
P. R. Silva
2013-02-01T23:59:59.000Z
A quantum vacuum, represented by a viscous fluid, is added to the Einstein vacuum, surrounding a spherical distribution of mass. This gives as a solution, in spherical coordinates, a Schwarzschild-like metric. The plot of g00 and g11 components of the metric, as a function of the radial coordinate, display the same qualitative behavior as that of the Schwarzschild metric. However, the temperature of the event horizon is equal to the Hawking temperature multiplied by a factor of two, while the entropy is equal to half of the Bekenstein one.
Mirza, Behrouz; Sherkatghanad, Zeinab [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)
2011-05-15T23:59:59.000Z
We study the AdS rotating black hole solution for the Bergshoeff-Hohm-Townsend massive gravity in three dimensions. The field equations of the asymptotically AdS black hole of the static metric can be expressed as the first law of thermodynamics, i.e. dE=TdS-PdV. The corrected Hawking-like temperature and entropy of the asymptotically AdS rotating black hole are calculated using the Cardy formula and the tunneling method. Comparison of these methods will help identify the unknown leading correction parameter {beta}{sub 1} in the tunneling method.
University Calendar, February 7, 2012
2012-02-07T23:59:59.000Z
.m. Atrium, Eaton Hall. Free. Sponsored by KU School of Engineering. Call 785-864-3891. Basketball (W). Women's Basketball vs. Texas. 7 p.m., Allen Fieldhouse. Sponsored by Department of Athletics. Call 800-34-HAWKS. 09 Thursday Workshop. i.... Sponsored by The Commons. Call 785-864-6293. 10 Friday Conference. Kansas Journal of Law & Public Policy Symposium. Corporate Tax Reform: Making America Competitive. 9 a.m. 106/107, Green Hall. Free. Sponsored by School of Law Alumni. Call 785...
Quantum frictionless trajectories versus geodesics
Luis C. Barbado; Carlos Barceló; Luis J. Garay
2015-05-15T23:59:59.000Z
Moving particles outside a star will generally experience quantum friction caused by Unruh radiation reaction. There exist however radial trajectories that lack this effect (in the outgoing radiation sector, and ignoring back-scattering). They turn out to have the property that the variations of the Doppler and the gravitational shifts compensate each other. They are not geodesics, and their proper acceleration obeys an inverse square law, which means that could in principle be generated by outgoing stellar radiation. In the case of a black hole emitting Hawking radiation, this may lead to a buoyancy scenario. The ingoing radiation sector has little effect and seems to slow down the fall even further.
Entanglement entropy from surface terms in general relativity
Arpan Bhattacharyya; Aninda Sinha
2013-09-10T23:59:59.000Z
Entanglement entropy in local quantum field theories is typically ultraviolet divergent due to short distance effects in the neighbourhood of the entangling region. In the context of gauge/gravity duality, we show that surface terms in general relativity are able to capture this entanglement entropy. In particular, we demonstrate that for 1+1 dimensional CFTs at finite temperature whose gravity dual is the BTZ black hole, the Gibbons-Hawking-York term precisely reproduces the entanglement entropy which can be computed independently in the field theory.
J. Kowalski-Glikman
2009-07-18T23:59:59.000Z
In this paper we construct, and investigate some thermal properties of, the non-commutative counterpart of Rindler space, which we call $\\kappa$--Rindler space. This space is obtained by changing variables in the defining commutators of $\\kappa$--Minkowski space. We then re-derive the commutator structure of $\\kappa$--Rindler space with the help of an appropriate star product, obtained from the $\\kappa$--Minkowski one. Using this star product, following the idea of Padmanabhan, we find the leading order, $1/\\kappa$ correction to the Hawking thermal spectrum.
Energy of gravitational radiation in plane-symmetric space-times
Sean A. Hayward
2008-05-19T23:59:59.000Z
Gravitational radiation in plane-symmetric space-times can be encoded in a complex potential, satisfying a non-linear wave equation. An effective energy tensor for the radiation is given, taking a scalar-field form in terms of the potential, entering the field equations in the same way as the matter energy tensor. It reduces to the Isaacson energy tensor in the linearized, high-frequency approximation. An energy conservation equation is derived for a quasi-local energy, essentially the Hawking energy. A transverse pressure exerted by interacting low-frequency gravitational radiation is predicted.
Generalized uncertainty principle in f(R) gravity for a charged black hole
Said, Jackson Levi [Physics Department, University of Malta, Msida (Malta); Adami, Kristian Zarb [Physics Department, University of Malta, Msida (Malta); Physics Department, University of Oxford, Oxford (United Kingdom)
2011-02-15T23:59:59.000Z
Using f(R) gravity in the Palatini formularism, the metric for a charged spherically symmetric black hole is derived, taking the Ricci scalar curvature to be constant. The generalized uncertainty principle is then used to calculate the temperature of the resulting black hole; through this the entropy is found correcting the Bekenstein-Hawking entropy in this case. Using the entropy the tunneling probability and heat capacity are calculated up to the order of the Planck length, which produces an extra factor that becomes important as black holes become small, such as in the case of mini-black holes.
T. N. Ukwatta; Jane H. MacGibbon; W. C. Parke; K. S. Dhuga; S. Rhodes; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris
2010-03-23T23:59:59.000Z
Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. The Fermi Gamma-ray Space Telescope observatory offers increased sensitivity to the gamma-ray bursts produced by PBHs with an initial mass of $\\sim 5\\times 10^{14}$ g expiring today. PBHs are candidate progenitors of unidentified Gamma-Ray Bursts (GRBs) that lack X-ray afterglow. We propose spectral lag, which is the temporal delay between the high and low energy pulses, as an efficient method to identify PBH evaporation events with the Fermi Large Area Telescope (LAT).
Quantum frictionless trajectories versus geodesics
Barbado, Luis C; Garay, Luis J
2015-01-01T23:59:59.000Z
Moving particles outside a star will generally experience quantum friction caused by Unruh radiation reaction. There exist however radial trajectories that lack this effect (in the outgoing radiation sector, and ignoring back-scattering). They turn out to have the property that the variations of the Doppler and the gravitational shifts compensate each other. They are not geodesics, and their proper acceleration obeys an inverse square law, which means that could in principle be generated by outgoing stellar radiation. In the case of a black hole emitting Hawking radiation, this may lead to a buoyancy scenario. The ingoing radiation sector has little effect and seems to slow down the fall even further.
Inhomogeneus Inflation and Cosmic no-Hair Conjecture
M. A. S. Nobre; M. R. de Garcia Maia; J. C. Carvalho; J. A. S. Lima
2009-03-20T23:59:59.000Z
The cosmic no hair conjecture is tested for a large class of inhomogeneous cosmologies with a positive cosmological constant. Firstly, we derive a new class of exact inhomogeneous cosmological solutions whose matter content of the models is formed by a mixture of two interacting simple fluids plus a cosmological Lambda-term. These models generalize the de Sitter spacetime and the inhomogeneous two-fluid Szekeres-type cosmologies derived by Lima and Tiomno. Finally, we show that the late time behaviour of our solutions is in agreement with the "cosmic no hair theorem" of Hawking and Moss.
The enriched phase structure of black branes in canonical ensemble
J. X. Lu; Shibaji Roy; Zhiguang Xiao
2011-10-10T23:59:59.000Z
It is found that a necessary completion of phase structure of D-dimensional charged black p-brane ($p > 0$) in a cavity requires two additional thermodynamical phases, the so-called "bubble of nothing" and/or the extremal brane, in canonical ensemble. This finding resolves the puzzle about the missing phases which are needed for the underlying phase diagram when $\\tilde d = D - p - 3 \\leq 2$ and gives a new (bubble) phase which can become globally stable when $\\tilde d > 2$. An analog of Hawking-Page transition is also found among other new phase transitions, giving a complete phase structure in this setup.
Radion clouds around evaporating black holes
J. R. Morris
2009-09-03T23:59:59.000Z
A Kaluza-Klein model, with a matter source associated with Hawking radiation from an evaporating black hole, is used to obtain a simple form for the radion effective potential. The environmental effect generally causes a matter-induced shift of the radion vacuum, resulting in the formation of a radion cloud around the hole. There is an albedo due to the radion cloud, with an energy dependent reflection coefficient that depends upon the size of the extra dimensions and the temperature of the hole.
NETL Researcher Honored with 2013 Federal Laboratory Consortium Award
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Sarah Wagoner | Department of Energy
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Save the Date: Tribal Energy Summit | Department of Energy
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Black Hills Corporation | Open Energy Information
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Black Hills Power Inc | Open Energy Information
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Black Hills Power, Inc. Smart Grid Project | Open Energy Information
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Black Rock III Geothermal Project | Open Energy Information
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Fish Lake Valley Geothermal Area | Open Energy Information
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn April 23, 2014,Zaleski - PolicyWork Force with even amountDefinitionsCarol Hawk
Cold Black Holes in the Harlow-Hayden Approach to Firewalls
Yen Chin Ong; Brett McInnes; Pisin Chen
2014-12-25T23:59:59.000Z
Firewalls are controversial principally because they seem to imply departures from general relativistic expectations in regions of spacetime where the curvature need not be particularly large. One of the virtues of the Harlow-Hayden approach to the firewall paradox, concerning the time available for decoding of Hawking radiation emanating from charged AdS black holes, is precisely that it operates in the context of cold black holes, which are not strongly curved outside the event horizon. Here we clarify this point. The approach is based on ideas borrowed from applications of the AdS/CFT correspondence to the quark-gluon plasma. Firewalls aside, our work presents a detailed analysis of the thermodynamics and evolution of evaporating charged AdS black holes with flat event horizons. We show that, in one way or another, these black holes are always eventually destroyed in a time which, while long by normal standards, is short relative to the decoding time of Hawking radiation.
The Transfer of Entanglement: The Case for Firewalls
Leonard Susskind
2012-10-07T23:59:59.000Z
Black hole complementarity requires that the interior of a black hole be represented by the same degrees of freedom that describe its exterior. Entanglement plays a crucial role in the reconstruction of the interior degrees of freedom. This connection is manifest in "two-sided" eternal black holes. But for real black holes which are formed from collapse there are no second sides. The sense in which horizon entropy is entanglement entropy is much more subtle for one-sided black holes. It involves entanglement between different parts of the near-horizon system. As a one-sided black hole evaporates the entanglement that accounts for its interior degrees of freedom disappears, and is gradually replaced by entanglement with the outgoing Hawking radiation. A principle of "transfer of entanglement" can be formulated. According to the argument of Almheiri, Marolf, Polchinski and Sully, it is when the transfer of entanglement is completed at the Page time, that a firewall replaces the horizon. Alternatives to firewalls may suffer contradictions which are similar to those of time travel. The firewall hypothesis would be similar to Hawking's chronology protection conjecture.
Gravitational Tunneling Radiation
Mario Rabinowitz
2002-12-11T23:59:59.000Z
The isolated black hole radiation of both Hawking and Zel'dovich are idealized abstractions as there is always another body to distort the potential. This is considered with respect to both gravitational tunneling, and black hole "no-hair" theorems. The effects of a second body are to lower the gravitational barrier of a black hole and to give the barrier a finite rather than infinite width so tha a particle can escape by tunneling (as in field emission) or over the top of the lowered barrier (as in Schottky emission). Thus radiation may be emitted from black holes in a process differing from that of Hawking radiation, P SH, which has been undetected for over 24 years. The radiated power from a black hole derived here is PR e ^2__ PSH, where e ^2__ is he ransmission probability for radiation through the barrier. This is similar to electric field emission of electrons from a metal in that the emission can in principle be modulated and beamed. The temperature and entropy of black holes are reexamined. Miniscule black holes herein may help explain the missing mass of the universe, accelerated expansion of the universe, and anomalous rotation of spiral galaxies. A gravitational interference effect for black hole radiation similar to the Aharonov-Bohm effect is also examined.
Time Evolution of Temperature and Entropy of a Gravitationally Collapsing Cylinder
Evan Halstead; Peng Hao
2011-06-12T23:59:59.000Z
We investigate the time evolution of the temperature and entropy of a gravitationally collapsing cylinder, represented by an infinitely thin domain wall, as seen by an asymptotic observer. Previous work has shown that the entropy of a spherically symmetric collapsing domain approaches a constant, and we follow this procedure using a (3+1) BTZ metric to see if a different topology will yield different results. We do this by coupling a scalar field to the background of the domain wall and analyzing the spectrum of radiation as a function of time. We find that the spectrum is quasi-thermal, with the degree of thermality increasing as the domain wall approaches the horizon. The thermal distribution allows for the determination of the temperature as a function of time, and we find that the late time temperature is very close to the Hawking temperature and that it also exhibits the proper scaling with the mass. From the temperature we find the entropy. Since the collapsing domain wall is what forms a black hole, we can compare the results to those of the standard entropy-area relation. We find that the entropy does in fact approach a constant that is close to the Hawking entropy. However, the time dependence of the entropy shows that the entropy decreases with time, indicating that a (3+1) BTZ domain wall will not collapse spontaneously.
Corda, Christian
2015-01-01T23:59:59.000Z
Some recent important results on black hole (BH) quantum physics concerning the BH effective state and the natural correspondence between Hawking radiation and BH quasi-normal modes (QNMs) are reviewed, clarified and refined. Such a correspondence permits to naturally interpret QNMs as quantum levels in a semi-classical model. This is a model of BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. In a certain sense, QNMs represent the "electron" which jumps from a level to another one and the absolute values of the QNMs frequencies "triggered" by emissions (Hawking radiation) and absorption of particles represent the energy "shells" of the "gravitational hydrogen atom". Important consequences on the BH information puzzle are discussed. In fact, it is shown that the time evolution of this "Bohr-like BH model" obeys to a time dependent Schr\\"odinger equation which permits the final BH state to be a pure quantum state instead of a mixed one. ...
The origin of thermal component in the transverse momentum spectra in high energy hadronic processes
Alexander A. Bylinkin; Dmitri E. Kharzeev; Andrei A. Rostovtsev
2014-07-15T23:59:59.000Z
The transverse momentum spectra of hadrons produced in high energy collisions can be decomposed into two components: the exponential ("thermal") and the power ("hard") ones. Recently, the H1 Collaboration has discovered that the relative strength of these two components in Deep Inelastic Scattering depends drastically upon the global structure of the event - namely, the exponential component is absent in the diffractive events characterized by a rapidity gap. We discuss the possible origin of this effect, and speculate that it is linked to confinement. Specifically, we argue that the thermal component is due to the effective event horizon introduced by the confining string, in analogy to the Hawking-Unruh effect. In diffractive events, the $t$-channel exchange is color-singlet and there is no fragmenting string -- so the thermal component is absent. The slope of the soft component of the hadron spectrum in this picture is determined by the saturation momentum that drives the deceleration in the color field, and thus the Hawking-Unruh temperature. We analyze the data on non-diffractive $pp$ collisions and find that the slope of the thermal component of the hadron spectrum is indeed proportional to the saturation momentum.
The Superheavy Elements and Anti-Gravity
Anastasovski, Petar K. [Department of Physics, Faculty of Technology and Metallurgy, Saints Cyril and Methodius University, Skopje (Macedonia, The Former Yugoslav Republic of)
2004-02-04T23:59:59.000Z
The essence of any propulsion concept is to overcome gravity. Anti-gravity is a natural means to achieve this. Thus, the technology to pursue anti-gravity, by using superheavy elements, may provide a new propulsion paradigm. The theory of superluminal relativity provides a hypothesis for existence of elements with atomic number up to Z = 145, some of which may possess anti-gravity properties. Analysis results show that curved space-time exists demonstrating both gravitic and anti-gravitic properties not only around nuclei but inside the nuclei as well. Two groups of elements (Z < 64 and 63 < Z <145) exist that demonstrate these capabilities. The nuclei of the first group of elements have the masses with only the property of gravity. The nuclei of the elements of the second group have the masses with both properties: gravity and anti-gravity in two different ranges of curved space-time around the nuclei.. The hypothetical element with Z = 145 is the unique among all elements whose nucleus has only anti-gravity property. It is proposed that this element be named Hawking, in honour of Stephen W. Hawking.
Quantum-Gravity Fluctuations and the Black-Hole Temperature
Hod, Shahar
2015-01-01T23:59:59.000Z
Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the {\\it discrete} quantum spectrum suggested by Bekenstein with the {\\it continuous} semi-classical spectrum suggested by Hawking ? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quanti...
The flaw in the firewall argument
Samir D. Mathur; David Turton
2014-05-28T23:59:59.000Z
A lot of confusion surrounds the issue of black hole complementarity, because the question has been considered without discussing the mechanism which guarantees unitarity. Considering such a mechanism leads to the following: (1) The Hawking quanta with energy E of order the black hole temperature T carry information, and so only appropriate processes involving E>>T quanta can have any possible complementary description with an information-free horizon; (2) The stretched horizon describes all possible black hole states with a given mass M, and it must expand out to a distance s_{bubble} before it can accept additional infalling bits; (3) The Hawking radiation has a specific low temperature T, and infalling quanta interact significantly with it only within a distance s_{alpha} of the horizon. One finds s_{alpha} >T, and this removes the argument against complementarity recently made by Almheiri et al. In particular, the condition E>>T leads to the notion of 'fuzzball complementarity', where the modes around the horizon are indeed correctly entangled in the complementary picture to give the vacuum.
Massmann, Alexander, E-mail: Alexander.Massmann@uks.eu; Katoh, Marcus [Saarland University Hospital, Department of Diagnostic and Interventional Radiology (Germany); Shayesteh-Kheslat, Roushanak [Saarland University Hospital, Department of General Surgery, Visceral, Vascular, and Pediatric Surgery (Germany); Buecker, Arno [Saarland University Hospital, Department of Diagnostic and Interventional Radiology (Germany)
2012-10-15T23:59:59.000Z
Purpose: To retrospectively examine the technical feasibility and safety of directional atherectomy for treatment of subacute infrainguinal arterial vessel occlusions. Methods: Five patients (one woman, four men, age range 51-81 years) with peripheral arterial disease who experienced sudden worsening of their peripheral arterial disease-related symptoms during the last 2-6 weeks underwent digital subtraction angiography, which revealed vessel occlusion in native popliteal artery (n = 4) and in-stent occlusion of the superficial femoral artery (n = 1). Subsequently, all patients were treated by atherectomy with the SilverHawk (ev3 Endovascular, USA) device. Results: The mean diameter of treated vessels was 5.1 {+-} 1.0 mm. The length of the occlusion ranged 2-14 cm. The primary technical success rate was 100%. One patient experienced a reocclusion during hospitalization due to heparin-induced thrombocytopenia. There were no further periprocedural complications, in particular no peripheral embolizations, until hospital discharge or during the follow-up period of 1 year. Conclusion: The recanalization of infrainguinal arterial vessel occlusions by atherectomy with the SilverHawk device is technically feasible and safe. In our limited retrospective study, it was associated with a high technical success rate and a low procedure-related complication rate.
Pawloski, G A
2012-01-30T23:59:59.000Z
This report evaluates collapse evolution for selected Lawrence Livermore National Laboratory (LLNL) underground nuclear tests at the Nevada National Security Site (NNSS, formerly called the Nevada Test Site). The work is being done to support several different programs that desire access to the ground surface above expended underground nuclear tests. The programs include: the Borehole Management Program, the Environmental Restoration Program, and the National Center for Nuclear Security Gas-Migration Experiment. Safety decisions must be made before a crater area, or potential crater area, can be reentered for any work. Evaluation of cavity collapse and crater formation is input into the safety decisions. Subject matter experts from the LLNL Containment Program who participated in weapons testing activities perform these evaluations. Information used included drilling and hole construction, emplacement and stemming, timing and sequence of the selected test and nearby tests, geology, yield, depth of burial, collapse times, surface crater sizes, cavity and crater volume estimations, ground motion, and radiological release information. Both classified and unclassified data were reviewed. The evaluations do not include the effects of erosion that may modify the collapse craters over time. They also do not address possible radiation dangers that may be present. Various amounts of information are available for these tests, depending on their age and other associated activities. Lack of data can hamper evaluations and introduce uncertainty. We make no attempt to quantify this uncertainty. Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Underground Nuclear Tests - 2011 was published on March 2, 2011. This report, considered Part 2 of work undertaken in calendar year 2011, compiles evaluations requested after the March report. The following unclassified summary statements describe collapse evolution and crater stability in response to a recent request to review 6 LLNL test locations in Yucca Flat, Rainier Mesa, and Pahute Mesa. They include: Baneberry in U8d; Clearwater in U12q; Wineskin in U12r, Buteo in U20a and Duryea in nearby U20a1; and Barnwell in U20az.
Quantum Cosmology will need to become a Numerical Subject
Anderson, Edward
2013-01-01T23:59:59.000Z
The inhomogeneous fluctuations that underlie structure formation - galaxies and CMB hotspots - might have been seeded by quantum cosmological fluctuations, as magnified by some inflationary mechanism. The Halliwell-Hawking model for these, as a lower-energy semiclassical limit, is expected to be shared by many theories. E.g. an O((H/m_pl)^2) suppression of power at large scales results from this. This model contains/suppresses very many terms; we want a qualitative understanding of the meaning of these terms and of different regimes resulting from different combinations of them. I study this with toy models that have tractable mathematics: minisuperspace and, especially, relational particle mechanics. In the present Seminar, I consider in particular averaged terms with some lessons from Hartree-Fock approach to Atomic and Molecular Physics. One needs to anchor this on variational principles; treating the subsequent equations is a numerical venture.
Quantum Cosmology will need to become a Numerical Subject
Edward Anderson
2013-06-26T23:59:59.000Z
The inhomogeneous fluctuations that underlie structure formation - galaxies and CMB hotspots - might have been seeded by quantum cosmological fluctuations, as magnified by some inflationary mechanism. The Halliwell-Hawking model for these, as a lower-energy semiclassical limit, is expected to be shared by many theories. E.g. an O((H/m_pl)^2) suppression of power at large scales results from this. This model contains/suppresses very many terms; we want a qualitative understanding of the meaning of these terms and of different regimes resulting from different combinations of them. I study this with toy models that have tractable mathematics: minisuperspace and, especially, relational particle mechanics. In the present Seminar, I consider in particular averaged terms with some lessons from Hartree-Fock approach to Atomic and Molecular Physics. One needs to anchor this on variational principles; treating the subsequent equations is a numerical venture.
Einstein-Born-Infeld black holes with a scalar hair in three-dimensions
S. Habib Mazharimousavi; M. Halilsoy
2014-08-15T23:59:59.000Z
We present a black hole solution in $2+1-$dimensional Einstein's theory of gravity coupled with Born-Infeld nonlinear electrodynamic and a massless self-interacting scalar field. The model has five free parameters: mass ($M$% ), cosmological constant ($\\ell $), electric ($q$) and scalar ($r_{0}$) charges and Born-Infeld parameter ($\\beta $). To attain exact solution for such a highly non-linear system we adjust, i.e. finely tune, the parameters of the theory with the integration constants. In the limit $\\beta \\rightarrow 0$ we recover the results of Einstein-Maxwell-Scalar theory, obtained before. The self interacting potential admits finite minima apt for the vacuum contribution. Hawking temperature of the model is investigated versus properly tuned parameters.
Thermodynamic geometry of charged rotating BTZ black holes
Akbar, M. [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, H-12, Islamabad (Pakistan); Quevedo, H. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, AP 70543, Mexico, DF 04510 (Mexico); ICRANet, Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy); Saifullah, K. [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan); Sanchez, A. [Departamento de Posgrado, CIIDET, AP 752, Queretaro, QRO 76000 (Mexico); Taj, S. [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, H-12, Islamabad (Pakistan); ICRANet, Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy)
2011-04-15T23:59:59.000Z
We study the thermodynamics and the thermodynamic geometries of charged rotating Banados-Teitelboim-Zanelli black holes in (2+1)-gravity. We investigate the thermodynamics of these systems within the context of the Weinhold and Ruppeiner thermodynamic geometries and the recently developed formalism of geometrothermodynamics. Considering the behavior of the heat capacity and the Hawking temperature, we show that Weinhold and Ruppeiner geometries cannot describe completely the thermodynamics of these black holes and of their limiting case of vanishing electric charge. In contrast, the Legendre invariance imposed on the metric in geometrothermodynamics allows one to describe the charged rotating Banados-Teitelboim-Zanelli black holes and their limiting cases in a consistent and invariant manner.
Decay of Graviton Condensates and their Generalizations in Arbitrary Dimensions
Florian Kuhnel; Bo Sundborg
2014-09-30T23:59:59.000Z
Classicalons are self-bound classical field configurations, which include black holes in General Relativity. In quantum theory, they are described by condensates of many soft quanta. In this work, their decay properties are studied in arbitrary dimensions. It is found that generically the decays of other classicalons are enhanced compared to pure graviton condensates, ie. black holes. The evaporation of higher dimensional graviton condensates turns out to match Hawking radiation solely due to non-linearites captured by the classicalon picture. Although less stable than black holes, all self-bound condensates are shown to be stable in the limit of large mass. Like for black holes, the effective coupling always scales as the inverse of the number of constituents, indicating that these systems are at critical points of quantum phase transitions. Consequences for cosmology, astro- and collider physics are briefly discussed.
Entropy bound for the photon gas in noncommutative spacetime
Nozari, K; Kamali, A Damavandi; Vakili, B
2015-01-01T23:59:59.000Z
Motivated by the doubly special relativity theories and noncommutative spacetime structures, thermodynamical properties of the photon gas in a phase space with compact spatial momentum space is studied. At the high temperature limit, the upper bounds for the internal energy and entropy are obtained which are determined by the size of the compact spatial momentum space. The maximum internal energy turns out to be of the order of the Planck energy and the entropy bound is then determined by the factor $\\big(V/l_{_{\\rm Pl}}^3\\big)$ through the relevant identification of the size of the momentum space with Planck scale. The entropy bound is very similar to the case of Bekenstein-Hawking entropy of black holes and suggests that thermodynamics of black holes may be deduced from a saturated state in the framework of a full quantum gravitational statistical mechanics.
K. Karami; A. Abdolmaleki
2011-01-31T23:59:59.000Z
We investigate the validity of the generalized second law of gravitational thermodynamics in a non-flat FRW universe containing the interacting new agegraphic dark energy with cold dark matter. The boundary of the universe is assumed to be enclosed by the dynamical apparent horizon. We show that for this model, the equation of state parameter can cross the phantom divide. We also present that for the selected model under thermal equilibrium with the Hawking radiation, the generalized second law is always satisfied throughout the history of the universe. Whereas, the evolution of the entropy of the universe and apparent horizon, separately, depends on the equation of state parameter of the interacting new agegraphic dark energy model.
The equivalence theorem in the generalized gravity of f(R)-type and canonical quantization II
Yasuo Ezawa; Yoshiaki Ohkuwa
2012-04-11T23:59:59.000Z
We first review the equivalence theorem of the f(R)-type gravity to Einstein gravity with a scalar field by deriving it in a self-contained and pedagogical way. Then we describe the problem of to what extent the equivalence holds. Main problems are (i) Is the surface term given by Gibbons and Hawking which is necessary in Einstein gravity also necessary in the f(R)-type gravity? (ii) Does the equivalence hold also in quantum theory? (iii) Which metric is physical, i.e., which metric should be identified with the observed one? In this work, we clarify the problem (i) and review the problem (ii) in a canonical formalism which is the generalization of the Ostrogradski one. We briefly comment on the problem (iii). Some discussions are given on one of the results of (ii) concerning the general relativity in non-commutative spacetime.
Gravitational radiation from dynamical black holes
Sean A. Hayward
2005-12-26T23:59:59.000Z
An effective energy tensor for gravitational radiation is identified for uniformly expanding flows of the Hawking mass-energy. It appears in an energy conservation law expressing the change in mass due to the energy densities of matter and gravitational radiation, with respect to a Killing-like vector encoding a preferred flow of time outside a black hole. In a spin-coefficient formulation, the components of the effective energy tensor can be understood as the energy densities of ingoing and outgoing, transverse and longitudinal gravitational radiation. By anchoring the flow to the trapping horizon of a black hole in a given sequence of spatial hypersurfaces, there is a locally unique flow and a measure of gravitational radiation in the strong-field regime.
H-band thermal emission from the 0.79-day period planet WASP-19b
Anderson, D R; Maxted, P F L; Barman, T S; Cameron, A Collier; Hellier, C; Queloz, D; Smalley, B; Triaud, A H M J
2010-01-01T23:59:59.000Z
We present the first ground-based detection of thermal emission from an exoplanet in the H-band. Using HAWK-I on the VLT, we observed an occultation of WASP-19b by its G8V-type host star. WASP-19b is a Jupiter-mass planet with an orbital period of only 0.79 d, and thus, being highly irradiated, is expected to be hot. We measure an H-band occultation depth of (0.259 +0.046 -0.044) %. A cloud-free model of the planet's atmosphere, with no redistribution of energy from day-side to night-side, under-predicts the planet/star flux density ratio by a factor of two. As the stellar parameters, and thus the level of planetary irradiation, are well-constrained by measurement, it is likely that our model of the planet's atmosphere is too simple.
Kensuke Homma
2009-11-30T23:59:59.000Z
High intense electromagnetic fields can be unique probes to study natures of macroscopic vacua by themselves. Combining accelerators with the intense field can provide more fruitful probes which can neither be achieved by only intense fields nor only high energy accelerators. We will overview the natures of vacua which can be accessible via intense laser-laser and intense laser-electron interactions. In the case of the laser-laser interaction, we propose how to observe nonlinear QED effects and effects of new fields like light scalar and pseudo scalar fields which may contribute to a macroscopic nature of our universe such as dark energy. In the case of the laser-electron interaction, in addition to nonlinear QED effects, we can further discuss the nature of accelerating field in the vacuum where we can access physics related with event horizons such as Hawking-Unruh radiations. We will introduce a recent experimental trial to search for this kind of odd radiations.
Signatures of Energy Flux in Particle Production: A Black Hole Birth Cry and Death Gasp
Good, Michael R R
2015-01-01T23:59:59.000Z
It is recently argued that if the Hawking radiation process is unitary, then a black hole's mass cannot be monotonically decreasing. We examine the time dependent particle count and negative energy flux in the non-trivial conformal vacuum via the moving mirror approach. A new, exactly unitary solution is presented which emits a characteristic above-thermal positive energy burst, a thermal plateau, and negative energy flux. It is found that the characteristic positive energy flare and thermal plateau is observed in the particle outflow. However, the results of time dependent particle production show no overt indication of negative energy flux. Therefore, a black hole's birth cry is detectable by asymptotic observers via particle count, whereas its death gasp is not.
The Case of the Missing Wormhole State
P. V. Moniz
1995-06-21T23:59:59.000Z
The issue concerning the existence of wormhole states in locally supersymmetric minisuperspace models with matter is addressed. Wormhole states are apparently absent in models obtained from the more general theory of N=1 supergravity with supermatter. A Hartle-Hawking type solution can be found, even though some terms (which are scalar field dependent) cannot be determined in a satisfactory way. A possible cause is investigated here. As far as the wormhole situation is concerned, we argue here that the type of Lagrange multipliers and fermionic derivative ordering one uses may make a difference. A proposal is made for supersymmetric quantum wormholes to also be invested with a Hilbert space structure, associated with a maximal analytical extension of the corresponding minisuperspace.
The boundary of Gödel's spacetime and the chronology protection conjecture
P. Pitanga
2012-01-09T23:59:59.000Z
We present a homogenous anisotropic conformal spacetime manifold that provide an example of Hawking's chronology protection conjecture in three-dimensional gravity theory. The solution is based upon the fact that the seven-dimensional group of the automorphism of the Heisenberg motion group H1{\\times}U(1), modulo discrete sub-group \\Gamma, is the symmetry group of the sub-Riemannian (SR)- manifold, boundary of the Cauchy-Riemann (CR)-manifold, allowing the existence of positive mass, momentum, angular-momentum and timelike-translation. It is shown that many mirror symmetric self-similar G\\"odel's surfaces are hidden behind a Cauchy spacelike surface so that causality violation is not visible from outside.
Gödel's universe and the chronology protection conjecture
P. Pitanga
2011-10-26T23:59:59.000Z
We present a solution for the geodesic motion in G\\"odel's universe that provides a particular proof of Hawking's chronology protection conjecture in three-dimensional gravity theory. The solution is based upon the fact that the group of the automorphisms of the Heisenberg motion group H1\\timesU(1), modulo discrete sub-group Z, act isometrically on the boundary of the hyperbolic three-dimensional manifold. Closed timelike curves do not exist due to the presence of a closed Cauchy-Riemann surface for chronology protection, with two mirror symmetric sets of helicoidal self-similar modules inside. The present solution is isometrically equivalent to a cylindrical gravitational monochromatic wave front.
Back to Basics?... or How can supersymmetry be used in simple quantum cosmological model
P. V. Moniz
1995-05-02T23:59:59.000Z
The general theory of N=1 supergravity with supermatter is applied to a Bianchi type IX diagonal model. The supermatter is constituted by a complex scalar field and its spin-$1\\over 2$ fermionic partners. The Lorentz invariant Ansatz for the wave function of the universe, $\\Psi$, is taken to be as simple as possible in order to obtain {\\it new} solutions. The wave function has a simple form when the potential energy term is set to zero. However, neither the wormhole or the Hartle-Hawking state could be found. The Ansatz for $\\Psi$ used in this paper is constrasted with the more general framework of R. Graham and A. Csord\\'as.
THE PLASMA WINDOW: A WINDOWLESS HIGH PRESSURE VACUUM INTERFACE FOR VARIOUS ACCELERATOR APPLICATIONS.
HERSHCOVITCH,A.I.; JOHNSON,E.D.; LANZA,R.C.
1999-03-29T23:59:59.000Z
The Plasma Window is a stabilized plasma arc used as an interface between accelerator vacuum and pressurized targets. There is no solid material introduced into the beam and thus it is also capable of transmitting particle beams and electromagnetic radiation with low loss and of sustaining high beam currents without damage. Measurements on a prototype system with a 3 mm diameter opening have shown that pressure differences of more than 2.5 atmospheres can be sustained with an input pressure of {approx} 10{sup -6} Torr. The system is capable of scaling to higher-pressure differences and larger apertures. Various plasma window applications for synchrotron light sources, high power lasers, internal targets, high current accelerators such as the HAWK, ATW, APT, DARHT, spallation sources, as well as for a number of commercial applications, will be discussed.
Logarithmic correction to BH entropy as Noether charge
R Aros; D E Diaz; A Montecinos
2010-03-04T23:59:59.000Z
We consider the role of the type-A trace anomaly in static black hole solutions to semiclassical Einstein equation in four dimensions. Via Wald's Noether charge formalism, we compute the contribution to the entropy coming from the anomaly induced effective action and unveil a logarithmic correction to the Bekenstein-Hawking area law. The corrected entropy is given by a seemingly universal formula involving the coefficient of the type-A trace anomaly, the Euler characteristic of the horizon and the value at the horizon of the solution to the uniformization problem for Q-curvature. Two instances are examined in detail: Schwarzschild and a four-dimensional massless topological black hole. We also find agreement with the logarithmic correction due to one-loop contribution of conformal fields in the Schwarzschild background.
Black Holes in the Cosmos, the Lab, and in Fundamental Physics (2/3)
None
2011-10-06T23:59:59.000Z
Black holes present the extreme limits of physics. They are ubiquitous in the cosmos, and in some extra-dimensional scenarios they could be produced at colliders. They have also yielded a puzzle that challenges the foundations of physics. These talks will begin with an overview of the basics of black hole physics, and then briefly summarize some of the exciting developments with cosmic black holes. They will then turn to properties of quantum black holes, and the question of black hole production in high energy collisions, perhaps beginning with the LHC. I will then overview the apparent paradox emerging from Hawking's discovery of black hole evaporation, and what it could be teaching us about the foundations of quantum mechanics and gravity.
Black Holes in the Cosmos, the Lab, and in Fundamental Physics (3/3)
None
2011-10-06T23:59:59.000Z
Black holes present the extreme limits of physics. They are ubiquitous in the cosmos, and in some extra-dimensional scenarios they could be produced at colliders. They have also yielded a puzzle that challenges the foundations of physics. These talks will begin with an overview of the basics of black hole physics, and then briefly summarize some of the exciting developments with cosmic black holes. They will then turn to properties of quantum black holes, and the question of black hole production in high energy collisions, perhaps beginning with the LHC. I will then overview the apparent paradox emerging from Hawking's discovery of black hole evaporation, and what it could be teaching us about the foundations of quantum mechanics and gravity.
Black Holes in the Cosmos, the Lab, and in Fundamental Physics (1/3)
None
2011-10-06T23:59:59.000Z
Black holes present the extreme limits of physics. They are ubiquitous in the cosmos, and in some extra-dimensional scenarios they could be produced at colliders. They have also yielded a puzzle that challenges the foundations of physics. These talks will begin with an overview of the basics of black hole physics, and then briefly summarize some of the exciting developments with cosmic black holes. They will then turn to properties of quantum black holes, and the question of black hole production in high energy collisions, perhaps beginning with the LHC. I will then overview the apparent paradox emerging from Hawking's discovery of black hole evaporation, and what it could be teaching us about the foundations of quantum mechanics and gravity.
Ajay Patwardhan
2008-05-15T23:59:59.000Z
In unified field theory the cosmological model of the universe has supersymmetric fields. Supersymmetric particles as dark and normal matter in galaxy clusters have a phase separation. Dark matter in halos have a statistical physics equation of state. Neutralino particle gas with gravitation can have a collapse of dark matter lumps. A condensate phase due to boson creation by annhillation and exchange can occur at high densities. The collapse of the boson condensate, including neutralinos, into the Schwarzschild radius creates dark matter black holes. Microscopic dark matter black holes can evaporate with Hawking effect giving gamma ray bursts and create a spectrum of normal particles. The phase separation of normal and dark matter in galaxy clusters and inside galaxies is given by statistical physics.
Graphene: QFT in curved spacetimes close to experiments
Alfredo Iorio
2013-04-09T23:59:59.000Z
A recently proposed step-by-step procedure, to merge the low-energy physics of the $\\pi$-bonds electrons of graphene, and quantum field theory on curved spacetimes, is recalled. The last step there is the proposal of an experiment to test a Hawking-Unruh effect, emerging from the model, that manifests itself as an exact (within the model) prediction for the electronic local density of states, in the ideal case of the graphene membrane shaped as a Beltrami pseudosphere. A discussion about one particular attempt to experimentally test the model on molecular graphene is presented, and it is taken as an excuse to solve some basic issues that will help future experiments. In particular, it is stated that the effect should be visible on generic surfaces of constant negative Gaussian curvature, that are infinite in number.
Stationary bound states of spin-half particles in the Reissner-Nordstroem gravitational field
M. V. Gorbatenko; V. P. Neznamov
2013-07-19T23:59:59.000Z
We prove the possibility of existence of stationary bound states of spin-half particles in the Reissner-Nordstroem gravitational field using a self-conjugate Hamiltonian with a flat scalar product of wave functions. Bound states of Dirac particles with a real discrete energy spectrum can exist both for particles above the external "event horizon", and for particles under the internal "event horizon", or the Cauchy horizon. The Hilbert condition g_{00}>0 leads to a boundary condition such that components of the vector of current density of Dirac particles are zero near the "event horizons". Based on the results of this study, we can assume that there exists a new type of charged collapsars, for which the Hawking radiation is not present. The results of this study can lead to a revision of some concepts of the standard cosmological model related to the evolution of the universe and interaction of charged collapsars with surrounding matter.
A Topological Interpretation of Mach's Principle in General Relativity
Thomas W. McLaughlin
2012-07-10T23:59:59.000Z
Starting from the Lovelock action and its supplementation by the relevant Gibbons-Hawking-York boundary term, the curvature action corresponding to second-order General Relativity is stated in accordance to the topological properties of the space-time manifold $\\mathcal{M}$ with metric solutions being interpreted as topological solitons. Furthermore, this is shown to arise naturally from a topological interpretation of Mach's principle, with the appropriate manifestation of general covariance. Mach's principle is again invoked to suggest formulations of the curvature action in alternative elliptic complexes. The extent of these deviations from the curvature action as constructed in the first part of this paper are remarked upon in the context of contemporary modified theories of gravity.
Andrew Beckwith
2014-04-15T23:59:59.000Z
Use of super-radiance in BH physics, so dE/dt past the planet Mercury.The present document makes a given differentiation between super-radiance in the case of conventional BHs and Braneworld BH super-radiance, which may delineate if Braneworlds contribute to an admissible massive graviton in terms of removing the usual problem of the 3/4th the bending of light past the planet Mercury which is normally associated with massive gravitons. This leads to a fork in the road, between two alternatives with the possibility of needing a multiverse containment of BH structure, or embracing what Hawkings wrote up recently, namely a re do of the Event Horizon hypothesis as we know it.
How to Determine the Probability of the Higgs Boson Detection
Alexander Unzicker
2009-12-02T23:59:59.000Z
The Higgs boson is the most important, though yet undiscovered ingredient of the standard model of particle physics. Its detection is therefore one of the most important goals of high energy physics that can guide future research in theoretical physics. Enormous efforts have been undertaken to prove the existence of the Higgs boson, and the physics community is excitedly awaiting the restart of the Large Hadron Collider at CERN. But how sure can we be that the Higgs exits at all? The German philosopher Immanuel Kant recommended betting at such controversial questions, and Stephen Hawking announced a $100 bet against the Higgs. But seriously, online prediction markets, which are a generalized form of betting, do provide the best possible probability estimates for future events. It is proposed that the scientific community uses this platforms for evaluation. See also an online description www.Bet-On-The-Higgs.com.
Wave blocking and partial transmission in subcritical flows over an obstacle
Léo-Paul Euvé; Florent Michel; Renaud Parentani; Germain Rousseaux
2015-02-06T23:59:59.000Z
We study and measure the transmission coefficient of counter-propagating shallow-water waves produced by a wave generator and scattered by an obstacle. To precisely compare theoretical predictions and experimental data, we consider $\\sim 25$ frequencies for 5 subcritical background flows, where the maximum value of the Froude number ranges from $0.5$ to $0.75$. For each flow, the transmission coefficient displays a sharp transition separating total transmission from wave-blocking. Both the width and the central frequency of the transition are in good agreement with their theoretical values. The shape of the obstacle is identical to that used by the Vancouver team in the recent experiment aiming at detecting the analogue of stimulated Hawking radiation. Our results are compatible with the observations that have been reported. They complete them by establishing that the contribution of the transmission coefficient cannot be neglected for the lower half of the probed frequency range.
Holographic Instanton Liquid and chiral transition
Bogeun Gwak; Minkyoo Kim; Bum-Hoon Lee; Yunseok Seo; Sang-Jin Sin
2012-03-22T23:59:59.000Z
In the presence of uniform D-instanton charges, quarks can be confined although gluons are not, because baryon vertices are allowed due to the net repulsive force on the on the probe D-branes. Since there is no scale in the geometry itself apart from the horizon size, there is no Hawking-Page transition. As a consequence, the D7 brane embedding can encode the effect of the the finite temperature as well as finite baryon density even for low temperature. The probe D-brane embedding, however, undergoes a chiral phase transition according to the temperature and density parameter. We studied such phase transitions and calculated the constituent quark mass, chiral condensation and the binding energy of baryons as function of the density. The baryon vertex melting is identified as the quark deconfinement. We draw phase diagram according to these transitions.
Quantum gravity effects in the Kerr spacetime
Reuter, M. [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany); Tuiran, E. [Departamento de Fisica, Universidad del Norte, Km 5 via a Puerto Colombia, AA-1569 Barranquilla (Colombia)
2011-02-15T23:59:59.000Z
We analyze the impact of the leading quantum gravity effects on the properties of black holes with nonzero angular momentum by performing a suitable renormalization group improvement of the classical Kerr metric within quantum Einstein gravity. In particular, we explore the structure of the horizons, the ergosphere, and the static limit surfaces as well as the phase space available for the Penrose process. The positivity properties of the effective vacuum energy-momentum tensor are also discussed and the 'dressing' of the black hole's mass and angular momentum are investigated by computing the corresponding Komar integrals. The pertinent Smarr formula turns out to retain its classical form. As for their thermodynamical properties, a modified first law of black-hole thermodynamics is found to be satisfied by the improved black holes (to second order in the angular momentum); the corresponding Bekenstein-Hawking temperature is not proportional to the surface gravity.
Notes on the firewall paradox, complexity, and quantum theory
Karl-Georg Schlesinger
2015-02-16T23:59:59.000Z
We investigate what it means to apply the solution, proposed to the firewall paradox by Harlow and Hayden, to the famous quantum paradoxes of Sch\\"odinger's Cat and Wigner's Friend if ones views these as posing a thermodynamic decoding problem (as does Hawking radiation in the firewall paradox). The implications might point to a relevance of the firewall paradox for the axiomatic and set theoretic foundations underlying mathematics. We reconsider in this context the results of Benioff on the foundational challenges posed by the randomness postulate of quantum theory. A central point in our discussion is that one can mathematically not naturally distinguish between computational complexity (as central to the approach of Harlow and Hayden and further developed by Susskind) and proof theoretic complexity (since they represent the same concept on a Turing machine), with the latter being related to a finite bound on Kolmogorov entropy (due to Chaitin incompleteness).
Wildlife studies on the Hanford Site: 1993 Highlights report
Cadwell, L.L. [ed.
1994-04-01T23:59:59.000Z
The Pacific Northwest Laboratory (PNL) Wildlife Resources Monitoring Project was initiated by DOE to track the status of wildlife populations to determine whether Hanford operations affected them. The project continues to conduct a census of wildlife populations that are highly visible, economically or aesthetically important, and rare or otherwise considered sensitive. Examples of long-term data collected and maintained through the Wildlife Resources Monitoring Project include annual goose nesting surveys conducted on islands in the Hanford Reach, wintering bald eagle surveys, and fall Chinook salmon redd (nest) surveys. The report highlights activities related to salmon and mollusks on the Hanford Reach of the Columbia River; describes efforts to map vegetation on the Site and efforts to survey species of concern; provides descriptions of shrub-steppe bird surveys, including bald eagles, Canada geese, and hawks; outlines efforts to monitor mule deer and elk populations on the Site; and describes development of a biological database management system.
Initial conditions for anisotropic extended-type inflationary universes
del Campo, S. (Instituto de Fisica, Universidad Catolica de Valparaiso, Avenida Brasil 2950, Valparaiso (Chile))
1992-05-15T23:59:59.000Z
Recently, extended-type inflationary universe models have been proposed as an appealing approach for solving most of the cosmological puzzles'' that, in contrast with previous models, do not require a fine-tuning'' for the microphysical parameters present in the effective potential. These scenarios rest on a Brans-Dicke-type theory, where a nonminimal coupling of the form {ital f}({ital cphi}){ital R} is assumed, and it may or may not include a potential for the Brans-Dicke field. In its classical description, different extended inflationary universe scenarios are described, where anisotropy is taken into account. By using the Hartle-Hawking and the Vilenkin boundary conditions for the wave function of the Universe, the probability distributions for the initial states of these extended models in the case of a small anisotropy are determined and discussed.
Abdel Nasser Tawfik; Eiman Abou El Dahab
2015-02-19T23:59:59.000Z
Recently, there has been much attention devoted to resolving the quantum corrections to the Bekenstein-Hawking (black hole) entropy, which relates the entropy to the cross-sectional area of the black hole horizon. Using generalized uncertainty principle (GUP), corrections to the geometric entropy and thermodynamics of black hole will be introduced. The impact of GUP on the entropy near the horizon of three types of black holes; Schwarzschild, Garfinkle-Horowitz-Strominger and Reissner-Nordstr\\"om is determined. It is found that the logarithmic divergence in the entropy-area relation turns to be positive. The entropy $S$, which is assumed to be related to horizon's two-dimensional area, gets an additional terms, for instance $2\\, \\sqrt{\\pi}\\, \\alpha\\, \\sqrt{S}$, where $\\alpha$ is the GUP parameter.
One-Loop Effective Action and Schwinger Effect in (Anti-) de Sitter Space
Rong-Gen Cai; Sang Pyo Kim
2014-09-04T23:59:59.000Z
We study the Schwinger mechanism by a uniform electric field in ${\\rm dS}_2$ and ${\\rm AdS}_2$ and the curvature effect on the Schwinger effect, and further propose a thermal interpretation of the Schwinger formula in terms of the Gibbons-Hawking temperature and the Unruh temperature for an accelerating charge in ${\\rm dS}_2$ and an analogous expression in ${\\rm AdS}_2$. The exact one-loop effective action is found in the proper-time integral in each space, which is determined by the effective mass, the Maxwell scalar, and the scalar curvature, and whose pole structure gives the imaginary part of the effective action and the exact pair-production rate. The exact pair-production rate is also given the thermal interpretation.
Black Hole Thermodynamics Based on Unitary Evolutions
Feng, Yu-Lei
2015-01-01T23:59:59.000Z
In this paper, we try to construct black hole thermodynamics based on the fact that, the formation and evaporation of a black hole can be described by quantum unitary evolutions. First, we show that the Bekenstein-Hawking entropy $S_{BH}$ cannot be a Boltzmann or thermal entropy. To confirm this statement, we show that the original black hole's "first law" cannot be treated as the first law of thermodynamics formally, due to some missing metric perturbations caused by matter. Then, by including those (quantum) metric perturbations, we show that the black hole formation and evaporation can be described in a unitary manner effectively, through a quantum channel between the exterior and interior of the event horizon. In this way, the paradoxes of information loss and firewall can be resolved effectively. Finally, we show that black hole thermodynamics can be constructed in an ordinary way, by constructing statistical mechanics.
Non-extremal fuzzballs and ergoregion emission
Borun D. Chowdhury; Samir D. Mathur
2008-10-23T23:59:59.000Z
In the traditional picture of black holes Hawking radiation is created by pair creation from the vacuum at the horizon. In the fuzzball proposal, individual microstates do not have a horizon with the `vacuum' state in its vicinity. For a special family of non-extremal microstates it was recently found that emission occurs due to pair creation in an ergoregion, rather than at a horizon. In this paper we extend this result to a slightly larger class of microstates, again finding exact agreement between the emission in the gravity picture and the CFT dual. We write down an expression for emission from geometries with ergoregions, in terms of the leading falloff behavior of the wavefunctions in the fuzzball region. Finally, we describe another family of nonextremal microstates and find their ergoregion.
Hidden conformal symmetry of extreme and non-extreme Einstein-Maxwell-Dilaton-Axion black holes
Deyou Chen; Hui Wang; Houwen Wu; Haitang Yang
2010-10-19T23:59:59.000Z
The hidden conformal symmetry of extreme and non-extreme Einstein-Maxwell-Dilaton-Axion (EMDA) black holes is addressed in this paper. For the non-extreme one, employing the wave equation of massless scalars, the conformal symmetry with left temperature $T_{L}=\\frac{M}{2\\pi a}$ and right temperature $T_{R}=\\frac{\\sqrt{M^{2}-a^{2}}}{2\\pi a}$ in the near region is found. The conformal symmetry is spontaneously broken due to the periodicity of the azimuthal angle. The microscopic entropy is derived by the Cardy formula and is fully in consistence with the Bekenstein-Hawking area-entropy law. The absorption cross section in the near region is calculated and exactly equals that in a 2D CFT. For the extreme case, by redefining the conformal coordinates, the duality between the solution space and CFT is studied. The microscopic entropy is found to exactly agree with the area-entropy law.
G. 't Hooft
2005-04-25T23:59:59.000Z
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.
Back to basics?... or how can supersymmetry be used in simple quantum cosmological model
Moniz, P V
1995-01-01T23:59:59.000Z
The general theory of N=1 supergravity with supermatter is applied to a Bianchi type IX diagonal model. The supermatter is constituted by a complex scalar field and its spin-1\\over 2 fermionic partners. The Lorentz invariant Ansatz for the wave function of the universe, \\Psi, is taken to be as simple as possible in order to obtain {\\it new} solutions. The wave function has a simple form when the potential energy term is set to zero. However, neither the wormhole or the Hartle-Hawking state could be found. The Ansatz for \\Psi used in this paper is constrasted with the more general framework of R. Graham and A. Csord\\'as.
The Membrane Paradigm and Firewalls
Tom Banks; Willy Fischler; Sandipan Kundu; Juan F. Pedraza
2013-10-02T23:59:59.000Z
Following the Membrane Paradigm, we show that the stretched horizon of a black hole retains information about particles thrown into the hole for a time of order the scrambling time m ln(m/M_P), after the particles cross the horizon. One can, for example, read off the proper time at which a particle anti-particle pair thrown into the hole, annihilates behind the horizon, if this time is less than the scrambling time. If we believe that the Schwarzschild geometry exterior to the horizon is a robust thermodynamic feature of the quantum black hole, independent of whether it is newly formed, or has undergone a long period of Hawking decay, then this classical computation shows that the "firewall" resolution of the AMPS paradox is not valid.
False vacuum decay in de Sitter space-time
V. A. Rubakov; S. M. Sibiryakov
1999-05-25T23:59:59.000Z
We suggest a technique that explicitly accounts for the structure of an initial state of quantum field in the semiclassical calculations of path integral in curved space-time, and consider decay of metastable state (conformal vacuum of scalar particles above false classical vacuum) in background de Sitter space-time as an example. Making use of this technique, we justify the Coleman-De Luccia approach to the calculation of the decay probability. We propose an interpretation of the Hawking-Moss instanton as a limiting case of constrained instantons. We find that an inverse process of the transition from true vacuum to false one is allowed in de Sitter space-time, and calculate the corresponding probability.
Decoherence delays false vacuum decay
Thomas C. Bachlechner
2013-04-17T23:59:59.000Z
We show that gravitational interactions between massless thermal modes and a nucleating Coleman-de Luccia bubble may lead to efficient decoherence and strongly suppress metastable vacuum decay for bubbles that are small compared to the Hubble radius. The vacuum decay rate including gravity and thermal photon interactions has the exponential scaling $\\Gamma\\sim\\Gamma_{CDL}^{2}$, where $\\Gamma_{CDL}$ is the Coleman-de Luccia decay rate neglecting photon interactions. For the lowest metastable initial state an efficient quantum Zeno effect occurs due to thermal radiation of temperatures as low as the de Sitter temperature. This strong decoherence effect is a consequence of gravitational interactions with light external mode. We argue that efficient decoherence does not occur for the case of Hawking-Moss decay. This observation is consistent with requirements set by Poincare recurrence in de Sitter space.
Jing Jiliang; Pan Qiyuan [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)
2005-06-15T23:59:59.000Z
We investigate the Dirac quasinormal modes (QNMs) of the Schwarzschild-anti-de Sitter and Reissner-Nordstrom-anti-de Sitter (SAdS/RNAdS) black holes using Horowitz-Hubeny approach. For large black holes, the fundamental QNMs are the linear functions of the Hawking temperature, and the slope of the lines decreases as the charge increases. For intermediate and small SAdS black holes, the real part of the fundamental QNMs approximates a temperature curve but the corresponding imaginary part is almost a linear function of the radius of the black hole. The quasinormal frequencies for high overtones become evenly spaced and the spacings are related to the mass and charge of the black hole. We also study the relation between QNMs and angular quantum number and find that the quasinormal frequencies increase as the angular quantum number increases.
Topological black holes in Horava-Lifshitz gravity
Cai Ronggen [Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China) and Kavli Institute for Theoretical Physics China (KITPC), Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Cao Liming [Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Ohta, Nobuyoshi [Department of Physics, Kinki University, Higashi-Osaka, Osaka 577-8502 (Japan)
2009-07-15T23:59:59.000Z
We find topological (charged) black holes whose horizon has an arbitrary constant scalar curvature 2k in Horava-Lifshitz theory. Without loss of generality, one may take k=1, 0, and -1. The black hole solution is asymptotically anti-de Sitter with a nonstandard asymptotic behavior. Using the Hamiltonian approach, we define a finite mass associated with the solution. We discuss the thermodynamics of the topological black holes and find that the black hole entropy has a logarithmic term in addition to an area term. We find a duality in Hawking temperature between topological black holes in Horava-Lifshitz theory and Einstein's general relativity: the temperature behaviors of black holes with k=1, 0, and -1 in Horava-Lifshitz theory are, respectively, dual to those of topological black holes with k=-1, 0, and 1 in Einstein's general relativity. The topological black holes in Horava-Lifshitz theory are thermodynamically stable.
Constraining the Braneworld with Gravitational Wave Observations
McWilliams, Sean T. [Gravitational Astrophysics Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt Maryland 20771 (United States)
2010-04-09T23:59:59.000Z
Some braneworld models may have observable consequences that, if detected, would validate a requisite element of string theory. In the infinite Randall-Sundrum model (RS2), the AdS radius of curvature, l, of the extra dimension supports a single bound state of the massless graviton on the brane, thereby reproducing Newtonian gravity in the weak-field limit. However, using the AdS/CFT correspondence, it has been suggested that one possible consequence of RS2 is an enormous increase in Hawking radiation emitted by black holes. We utilize this possibility to derive two novel methods for constraining l via gravitational wave measurements. We show that the EMRI event rate detected by LISA can constrain l at the {approx}1 {mu}m level for optimal cases, while the observation of a single galactic black hole binary with LISA results in an optimal constraint of l{<=}5 {mu}m.
Sinton, D.T.; Kennedy, P.L. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Fishery and Wildlife Biology
1994-06-01T23:59:59.000Z
Northern goshawks (Accipiter gentilis) (hereafter referred to as goshawk) is a large forest dwelling hawk. Goshawks may be declining in population and reproduction in the southwestern United States. Reasons for the possible decline in goshawk populations include timber harvesting resulting in the loss of nesting habitat, toxic chemicals, and the effects of drought, fire, and disease. Thus, there is a need to determine their population status and assess impacts of management activities in potential goshawk habitat. Inventory for the goshawk was conducted on 2,254 ha of Los Alamos National Laboratory (LANL) to determine the presence of nesting goshawks on LANL lands. This information can be incorporated into LANL`s environmental management program. The inventory was conducted by Colorado State University personnel from May 12 to July 30, 1993. This report summarizes the results of this inventory.
Dariush Kaviani; Amir Esmaeil Mosaffa
2015-03-06T23:59:59.000Z
We study the temperature of extended objects in string theory. Rotating D-branes in warped Calabi-Yau throats have induced metrics with thermal horizons and Hawking temperatures a la Unruh effect. We solve the equations of motion for slow rotating probe branes and derive their induced metrics in the UV/IR solutions of warped conifold throats. Our analysis shows that horizons and temperatures of expected features form on the world volume of the rotating probe brane in terms of conserved charges in the UV solutions of the conifold throat. In certain limits, we find world volume horizons and temperatures of the form similar to those of rotating probes in the AdS throat.
A New Proposal for Matrix Theory
Shyamoli Chaudhuri
2005-07-24T23:59:59.000Z
We explain the motivation and main ideas underlying our proposal for a Lagrangian for Matrix Theory based on sixteen supercharges. Starting with the pedagogical example of a bosonic matrix theory we describe the appearance of a continuum spacetime geometry from a discrete, and noncommutative, spacetime with both Lorentz and Yang-Mills invariances. We explain the appearance of large N ground states with Dbranes and elucidate the principle of matrix Dbrane democracy at finite N. Based on the underlying symmetry algebras that hold at both finite and infinite N, we show why the supersymmetric matrix Lagrangian we propose does not belong to the class of supermatrix models which includes the BFSS and IKKT Matrix Models. We end with a preliminary discussion of a path integral prescription for the Hartle-Hawking wavefunction of the Universe derived from Matrix Theory.
Gödel black hole, closed timelike horizon, and the study of particle emissions
Sourav Bhattacharya; Anirban Saha
2010-07-22T23:59:59.000Z
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.
Black Hole Fluctuations and Backreaction in Stochastic Gravity
Sukanya Sinha; Alpan Raval; B. L. Hu
2002-10-04T23:59:59.000Z
We present a framework for analyzing black hole backreaction from the point of view of quantum open systems using influence functional formalism. We focus on the model of a black hole described by a radially perturbed quasi-static metric and Hawking radiation by a conformally coupled massless quantum scalar field. It is shown that the closed-time-path (CTP) effective action yields a non-local dissipation term as well as a stochastic noise term in the equation of motion, the Einstein-Langevin equation. Once the thermal Green's function in a Schwarzschild background becomes available to the required accuracy the strategy described here can be applied to obtain concrete results on backreaction. We also present an alternative derivation of the CTP effective action in terms of the Bogolyubov coefficients, thus making a connection with the interpretation of the noise term as measuring the difference in particle production in alternative histories.
Phase Structure of Higher Spin Black Holes
Abhishek Chowdhury; Arunabha Saha
2015-02-12T23:59:59.000Z
We revisit the study of the phase structure of higher spin black holes carried out in arXiv$:1210.0284$ using the "canonical formalism". In particular we study the low as well as high temperature regimes. We show that the Hawking-Page transition takes place in the low temperature regime. The thermodynamically favoured phase changes from conical surplus to black holes and then again to conical surplus as we increase temperature. We then show that in the high temperature regime the diagonal embedding gives the appropriate description. We also give a map between the parameters of the theory near the IR and UV fixed points. This makes the "good" solutions near one end map to the "bad" solutions near the other end and vice versa.
Superconductivity, Superfluidity and Holography
Alberto Salvio
2013-01-16T23:59:59.000Z
This is a concise review of holographic superconductors and superfluids. We highlight some predictions of the holographic models and the emphasis is given to physical aspects rather than to the technical details, although some references to understand the latter are systematically provided. We include gapped systems in the discussion, motivated by the physics of high-temperature superconductivity. In order to do so we consider a compactified extra dimension (with radius R), or, alternatively, a dilatonic field. The first setup can also be used to model cylindrical superconductors; when these are probed by an axial magnetic field a universal property of holography emerges: while for large R (compared to the other scales in the problem) non-local operators are suppressed, leading to the so called Little-Parks periodicity, the opposite limit shows non-local effects, e.g. the uplifting of the Little-Parks periodicity. This difference corresponds in the gravity side to a Hawking-Page phase transition.
Brito, Richard; Pani, Paolo
2015-01-01T23:59:59.000Z
Superradiance is a radiation enhancement process that involves dissipative systems. With a 60 year-old history, superradiance has played a prominent role in optics, quantum mechanics and especially in relativity and astrophysics. In General Relativity, black-hole superradiance is permitted by dissipation at the event horizon, that allows for energy and angular momentum extraction from the vacuum, even at the classical level. Black-hole superradiance is intimately connected to the black-hole area theorem, Penrose process, tidal forces and even Hawking radiation, which can be interpreted as a quantum version of black-hole superradiance. Various mechanisms (as diverse as massive fields, magnetic fields, anti-de Sitter boundaries, nonlinear interactions, etc...) can confine the amplified radiation and give rise to strong instabilities. These "black-hole bombs" have applications in searches of dark matter and of physics beyond the Standard Model, are associated to the threshold of formation of new black hole solut...
Phase transitions of regular Schwarzschild-Anti-deSitter black holes
Frassino, Antonia Micol
2015-01-01T23:59:59.000Z
We study a solution of the Einstein's equations generated by a self-gravitating, anisotropic, static, non-singular matter fluid. The resulting Schwarzschild like solution is regular and accounts for smearing effects of noncommutative fluctuations of the geometry. We call this solution regular Schwarzschild spacetime. In the presence of an Anti-deSitter cosmological term, the regularized metric offers an extension of the Hawking-Page transition into a van der Waals-like phase diagram. Specifically the regular Schwarzschild-Anti-deSitter geometry undergoes a first order small/large black hole transition similar to the liquid/gas transition of a real fluid. In the present analysis we have considered the cosmological constant as a dynamical quantity and its variation is included in the first law of black hole thermodynamics.
Condensation of an ideal gas with intermediate statistics on the horizon
Somayeh Zare; Zahra Raissi; Hosein Mohammadzadeh; Behrouz Mirza
2012-09-22T23:59:59.000Z
We consider a boson gas on the stretched horizon of the Schwartzschild and Kerr black holes. It is shown that the gas is in a Bose-Einstein condensed state with the Hawking temperature $T_c=T_H$ if the particle number of the system be equal to the number of quantum bits of space-time $ N \\simeq {A}/{{\\l_{p}}^{2}}$. Entropy of the gas is proportional to the area of the horizon $(A)$ by construction. For a more realistic model of quantum degrees of freedom on the horizon, we should presumably consider interacting bosons (gravitons). An ideal gas with intermediate statistics could be considered as an effective theory for interacting bosons. This analysis shows that we may obtain a correct entropy just by a suitable choice of parameter in the intermediate statistics.
Bose-Einstein Condensation on Holographic Screens
Mirza, Behrouz; Raissi, Zahra
2011-01-01T23:59:59.000Z
We consider a boson gas on holographic screens of the Rindler and Schwartzschild spacetimes. It is shown that the gas on the stretched horizon is in a Bose-Einstein condensed state with the Hawking temperature $T_c=T_H$ if the particle number of the system be equal to the number of quantum bits of spacetime $ N \\simeq {A}/{{\\l_{p}}^{2}}$. A boson gas on a holographic screen $(r>2M)$ with the same number of particles and at Unruh temperature is also in a condensed state. Far from the horizon, the Unruh temperature is much lower than the condensation temperature $(T_c=T_{{Unruh}}+\\sqrt {f(r)} T_{Planck})$. This analysis implies a possible physical model for quantum bits of spacetime on a holographic screen. We propose a unique and physical interpretation for equipartition theorem on holographic screens. Also, we will argue that this gas is a fast scrambler.
Unruh effect and condensate in and out of an accelerated vacuum
Sanjin Benic; Kenji Fukushima
2015-03-31T23:59:59.000Z
We address a physical interpretation of the Hawking-Unruh effect with our emphasis put on judicious consideration of observables and vacua with and without acceleration. In particular we discuss thermal-like corrections using explicit computation of correlation functions. We identify the correspondence between thermo-field dynamics and accelerated systems. Then we make it clear that a genuine thermal state corresponds to a non-accelerated frame, while vacuum states correspond to Rindler wedges, which accounts for a negative contribution of the thermal-like correction measured in the accelerated vacuum. We apply our results to investigate how the acceleration effect would affect a condensate of fields. Our conclusion is that a larger acceleration should enhance a condensate as compared to those in a non-accelerated vacuum.
Universality of high-energy absorption cross sections for black holes
Decanini, Yves [Equipe Physique Theorique, SPE, UMR 6134 du CNRS et de l'Universite de Corse, Universite de Corse, Faculte des Sciences, B.P. 52, F-20250 Corte (France); Esposito-Farese, Gilles [GReCO, Institut d'Astrophysique de Paris, UMR 7095 du CNRS et de l'Universite Pierre et Marie Curie-Paris 6, 98bis boulevard Arago, F-75014 Paris (France); Folacci, Antoine [Equipe Physique Theorique, SPE, UMR 6134 du CNRS et de l'Universite de Corse, Universite de Corse, Faculte des Sciences, B.P. 52, F-20250 Corte (France); Centre de Physique Theorique, UMR 6207 du CNRS et des Universites Aix-Marseille 1 et 2 et de l'Universite du Sud Toulon-Var, CNRS-Luminy Case 907, F-13288 Marseille (France)
2011-02-15T23:59:59.000Z
We consider the absorption problem for a massless scalar field propagating in static and spherically symmetric black holes of arbitrary dimension endowed with a photon sphere. For this wide class of black holes, we show that the fluctuations of the high-energy absorption cross section are totally and very simply described from the properties (dispersion relation and damping) of the waves trapped near the photon sphere and therefore, in the eikonal regime, from the characteristics (orbital period and Lyapunov exponent) of the null unstable geodesics lying on the photon sphere. This is achieved by using Regge pole techniques. They permit us to make an elegant and powerful resummation of the absorption cross section and to extract then all the physical information encoded in the sum over the partial wave contributions. Our analysis induces moreover some consequences concerning Hawking radiation which we briefly report.
Nonsingular Decaying Vacuum Cosmology and Entropy Production
J. A. S. Lima; S. Basilakos; Joan Solà
2015-03-08T23:59:59.000Z
The thermodynamic behavior of a decaying vacuum cosmology describing the entire cosmological history evolving between two extreme (early and late time) de Sitter eras is investigated. The thermal evolution from the early de Sitter to the radiation phase is discussed in detail. The temperature evolution law and the increasing entropy function are analytically determined. The entropy of the effectively massless particles is initially zero but evolves continuously to the present day maximum value within the current Hubble radius, $S_0 \\sim 10^{88}$ in natural units. By using the Gibbons-Hawking temperature relation for the de Sitter spacetime, it is found that the ratio between the primeval and the late time vacuum energy densities is $\\rho_{vI}/\\rho_{v0} \\sim 10^{123}$, as required by some naive estimates from quantum field theory.
On the temperature dependence of the absorption cross section for charged black holes
Filipe Moura
2014-06-08T23:59:59.000Z
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.
Gia Dvali; Cesar Gomez
2012-03-29T23:59:59.000Z
According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.
Time Evolution of Temperature and Entropy of Various Collapsing Domain Walls
Evan Halstead
2012-09-10T23:59:59.000Z
We investigate the time evolution of the temperature and entropy of gravitationally collapsing domain walls as seen by an asymptotic observer. In particular, we seek to understand how topology and the addition of a cosmological constant affect the gravitational collapse. Previous work has shown that the entropy of a spherically symmetric collapsing domain approaches a constant. In this paper, we reproduce these results, using both a fully quantum and a semi-classical approach, then we repeat the process for a de Sitter Schwarzschild domain wall (spherical with cosmological constant) and a (3+1) BTZ domain wall (cylindrical). We do this by coupling a scalar field to the background of the domain wall and analyzing the spectrum of radiation as a function of time. We find that the spectrum is quasi-thermal, with the degree of thermality increasing as the domain wall approaches the horizon. The thermal distribution allows for the determination of the temperature as a function of time, and we find that the late time temperature is very close to the Hawking temperature and that it also exhibits the proper scaling with the mass. From the temperature we find the entropy. Since the collapsing domain wall is what forms a black hole, we can compare the results to those of the standard entropy-area relation. We find that the entropy does in fact approach a constant that is close to the Hawking entropy. However, both the de Sitter Schwarzschild domain wall and the (3+1) BTZ domain wall show periods of decreasing entropy, which suggests that spontaneous collapse may be prevented.
The gravitational Hamiltonian, first order action, Poincaré charges and surface terms
Alejandro Corichi; Juan D. Reyes
2015-05-06T23:59:59.000Z
We consider the issue of attaining a consistent Hamiltonian formulation, after a 3+1 splitting, of a well-defined action principle for asymptotically flat gravity. More precisely, our starting point is the gravitational first order Holst action with surface terms and fall-off conditions that make the variational principle and the covariant phase space formulation well-defined for asymptotically flat spacetimes. Keeping all surface terms and paying due attention to subtleties that arise from the different cut-offs at infinity, we give a derivation of the gravitational Hamiltonian starting from this action. The 3+1 decomposition and time gauge fixing results in a well-defined Hamiltonian action and a well-defined Hamiltonian formulation for the standard -and more general- asymptotic ADM conditions. Unlike the case of the Einstein-Hilbert action with Gibbons-Hawking-York or Hawking-Horowitz terms, here we {\\it {do}} recover the ADM energy-momentum from the covariant surface term also when more general variations respecting asymptotic flatness are allowed. Additionally, our strategy yields a derivation of the parity conditions for connection variables independent of the conditions given by Regge and Teitelboim for ADM variables. Finally, we exhibit the other Poincar\\'e generators in terms of real Ashtekar-Barbero variables. We complement previous constructions in self-dual variables by pointing out several subtleties and refining the argument showing that -on shell- they coincide with the ADM charges. Our results represent the first consistent treatment of the Hamiltonian formulation for the connection-tetrad gravitational degrees of freedom, starting from a well posed action, in the case of asymptotically flat boundary conditions.
Christian Corda
2015-03-25T23:59:59.000Z
Some recent important results on black hole (BH) quantum physics concerning the BH effective state and the natural correspondence between Hawking radiation and BH quasi-normal modes (QNMs) are reviewed, clarified and refined. Such a correspondence permits to naturally interpret QNMs as quantum levels in a semi-classical model. This is a model of BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. In a certain sense, QNMs represent the "electron" which jumps from a level to another one and the absolute values of the QNMs frequencies "triggered" by emissions (Hawking radiation) and absorption of particles represent the energy "shells" of the "gravitational hydrogen atom". Important consequences on the BH information puzzle are discussed. In fact, it is shown that the time evolution of this "Bohr-like BH model" obeys to a time dependent Schr\\"odinger equation which permits the final BH state to be a pure quantum state instead of a mixed one. Thus, information comes out in BH evaporation, in agreement with the assumption by 't Hooft that Schr\\"oedinger equations can be used universally for all dynamics in the universe. We also show that, in addition, our approach solves the entanglement problem connected with the information paradox. We emphasize that Bohr model is an approximated model of the hydrogen atom with respect to the valence shell atom model of full quantum mechanics. In the same way, we expect the Bohr-like BH model to be an approximated model with respect to the definitive, but at the present time unknown, BH model arising from a full quantum gravity theory.
Christian Corda
2015-02-26T23:59:59.000Z
Some recent important results on black hole (BH) quantum physics concerning the BH effective state and the natural correspondence between Hawking radiation and BH quasi-normal modes (QNMs) are reviewed, clarified and refined. Such a correspondence permits to naturally interpret QNMs as quantum levels in a semi-classical model. This is a model of BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. In a certain sense, QNMs represent the "electron" which jumps from a level to another one and the absolute values of the QNMs frequencies "triggered" by emissions (Hawking radiation) and absorption of particles represent the energy "shells" of the "gravitational hydrogen atom". Important consequences on the BH information puzzle are discussed. In fact, it is shown that the time evolution of this "Bohr-like BH model" obeys to a time dependent Schr\\"odinger equation which permits the final BH state to be a pure quantum state instead of a mixed one. Thus, information comes out in BH evaporation, in agreement with the assumption by 't Hooft that Schr\\"oedinger equations can be used universally for all dynamics in the universe. We also show that, in addition, our approach solves the entanglement problem connected with the information paradox. We emphasize that Bohr model is an approximated model of the hydrogen atom with respect to the valence shell atom model of full quantum mechanics. In the same way, we expect the Bohr-like BH model to be an approximated model with respect to the definitive, but at the present time unknown, BH model arising from a full quantum gravity theory. If the analogy between electron and QNMs is correct, this could be the first, important step for the realization of a new approach to quantum gravity that we could call "QNMs quantum gravity".
Christian Corda
2015-03-31T23:59:59.000Z
Some recent important results on black hole (BH) quantum physics concerning the BH effective state and the natural correspondence between Hawking radiation and BH quasi-normal modes (QNMs) are reviewed, clarified and refined. Such a correspondence permits to naturally interpret QNMs as quantum levels in a semi-classical model. This is a model of BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. In a certain sense, QNMs represent the "electron" which jumps from a level to another one and the absolute values of the QNMs frequencies "triggered" by emissions (Hawking radiation) and absorption of particles represent the energy "shells" of the "gravitational hydrogen atom". Important consequences on the BH information puzzle are discussed. In fact, it is shown that the time evolution of this "Bohr-like BH model" obeys to a time dependent Schr\\"odinger equation which permits the final BH state to be a pure quantum state instead of a mixed one. Thus, information comes out in BH evaporation, in agreement with the assumption by 't Hooft that Schr\\"oedinger equations can be used universally for all dynamics in the universe. We also show that, in addition, our approach solves the entanglement problem connected with the information paradox. We emphasize that Bohr model is an approximated model of the hydrogen atom with respect to the valence shell atom model of full quantum mechanics. In the same way, we expect the Bohr-like BH model to be an approximated model with respect to the definitive, but at the present time unknown, BH model arising from a full quantum gravity theory.
Paul M. Alsing
2015-02-04T23:59:59.000Z
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.
Black Hole Evaporation as a Nonequilibrium Process
Hiromi Saida
2008-11-11T23:59:59.000Z
When a black hole evaporates, there arises a net energy flow from the black hole into its outside environment due to the Hawking radiation and the energy accretion onto black hole. Exactly speaking, due to the net energy flow, the black hole evaporation is a nonequilibrium process. To study details of evaporation process, nonequilibrium effects of the net energy flow should be taken into account. In this article we simplify the situation so that the Hawking radiation consists of non-self-interacting massless matter fields and also the energy accretion onto the black hole consists of the same fields. Then we find that the nonequilibrium nature of black hole evaporation is described by a nonequilibrium state of that field, and we formulate nonequilibrium thermodynamics of non-self-interacting massless fields. By applying it to black hole evaporation, followings are shown: (1) Nonequilibrium effects of the energy flow tends to accelerate the black hole evaporation, and, consequently, a specific nonequilibrium phenomenon of semi-classical black hole evaporation is suggested. Furthermore a suggestion about the end state of quantum size black hole evaporation is proposed in the context of information loss paradox. (2) Negative heat capacity of black hole is the physical essence of the generalized second law of black hole thermodynamics, and self-entropy production inside the matter around black hole is not necessary to ensure the generalized second law. Furthermore a lower bound for total entropy at the end of black hole evaporation is given. A relation of the lower bound with the so-called covariant entropy bound conjecture is interesting but left as an open issue.
3D CFD Model of High Temperature H2O/CO2 Co-electrolysis
Grant Hawkes; James O'Brien; Carl Stoots; Stephen Herring; Joe Hartvigsen
2007-06-01T23:59:59.000Z
3D CFD Model of High Temperature H2O/CO2 Co-Electrolysis Grant Hawkes1, James O’Brien1, Carl Stoots1, Stephen Herring1 Joe Hartvigsen2 1 Idaho National Laboratory, Idaho Falls, Idaho, grant.hawkes@inl.gov 2 Ceramatec Inc, Salt Lake City, Utah INTRODUCTION A three-dimensional computational fluid dynamics (CFD) model has been created to model high temperature co-electrolysis of steam and carbon dioxide in a planar solid oxide electrolyzer (SOE) using solid oxide fuel cell technology. A research program is under way at the Idaho National Laboratory (INL) to simultaneously address the research and scale-up issues associated with the implementation of planar solid-oxide electrolysis cell technology for syn-gas production from CO2 and steam. Various runs have been performed under different run conditions to help assess the performance of the SOE. This paper presents CFD results of this model compared with experimental results. The Idaho National Laboratory (INL), in conjunction with Ceramatec Inc. (Salt Lake City, USA) has been researching for several years the use of solid-oxide fuel cell technology to electrolyze steam for large-scale nuclear-powered hydrogen production. Now, an experimental research project is underway at the INL to produce syngas by simultaneously electrolyzing at high-temperature steam and carbon dioxide (CO2) using solid oxide fuel cell technology. A strong interest exists in the large-scale production of syn-gas from CO2 and steam to be reformed into a usable transportation fuel. If biomass is used as the carbon source, the overall process is climate neutral. Consequently, there is a high level of interest in production of syn-gas from CO2 and steam electrolysis. With the price of oil currently around $60 / barrel, synthetically-derived hydrocarbon fuels (synfuels) have become economical. Synfuels are typically produced from syngas – hydrogen (H2) and carbon monoxide (CO) -- using the Fischer-Tropsch process, discovered by Germany before World War II. High-temperature nuclear reactors have the potential for substantially increasing the efficiency of syn-gas production from CO2 and water, with no consumption of fossil fuels, and no production of greenhouse gases. Thermal CO2-splitting and water splitting for syn-gas production can be accomplished via high-temperature electrolysis, using high-temperature nuclear process heat and electricity. A high-temperature advanced nuclear reactor coupled with a high-efficiency high-temperature electrolyzer could achieve a competitive thermal-to-syn-gas conversion efficiency of 45 to 55%.
PROTOSTARS AND STARS IN THE CORONET CLUSTER: AGE, EVOLUTION, AND CLUSTER STRUCTURE
Sicilia-Aguilar, Aurora; Henning, Thomas; Kainulainen, Jouni [Max-Planck-Institut fuer Astronomie, 69117 Heidelberg (Germany); Roccatagliata, Veronica, E-mail: sicilia@mpia.de [Space Telescope Science Institute, Baltimore, MD 21218 (United States)
2011-08-01T23:59:59.000Z
We present new optical spectroscopy with the FLAMES spectrograph at the Very Large Telescope (VLT), near-IR imaging with VLT/HAWK-I, and 870 {mu}m mapping with APEX/LABOCA of the Coronet cluster. The optical data allow us to estimate spectral types, extinction, and the presence of accretion in 6 more M-type members, in addition to the 12 that we had previously studied. The submillimeter maps and near-IR data reveal the presence of nebular structures and high extinction regions, which are in some cases associated to known IR, optical, and X-ray sources. Most star formation is associated to two elongated structures crossing in the central part of the cluster. Placing all the 18 objects with known spectral types and extinction in an H-R diagram suggests that the cluster is younger than previously thought (<2 Myr, and probably {approx}0.5-1 Myr). The new age estimate is in agreement with the evolutionary status of the various protostars in the region and with its compactness (<1.3 pc across), but results in a conflict with the low disk and accretion fraction (only 50%-65% of low-mass stars appear to have protoplanetary disks, and most transitional and homologously depleted disks are consistent with no accretion) and with the evolutionary features observed in the mid-IR spectra and spectral energy distributions of the disks.
Singularities, Firewalls, and Complementarity
Leonard Susskind
2012-08-16T23:59:59.000Z
Almheiri, Marolf, Polchinski, and Sully, recently claimed that once a black hole has radiated more than half its initial entropy (the Page time), the horizon is replaced by a "firewall" at which infalling observers burn up, in apparent violation of the equivalence principle and the postulates of black hole complementarity. In this paper I review the arguments for firewalls, and give a slightly different interpretation of them. According to this interpretation the horizon has standard properties, but the singularity is non-standard. The growing entanglement of the black hole with Hawking radiation causes the singularity to migrate toward the horizon, and eventually intersect it at the page time. The resulting collision of the singularity with the horizon leads to the firewall. Complementarity applies to the horizon and not to the singular firewall. Almheiri, Marolf, Polchinski, and Sully conjecture that firewalls form much earlier then the Page time; namely at the scrambling time. I argue that there is no reason to believe this generalization, and good reason to think it is wrong. For most of this paper I will assume that the firewall argument is correct. In the last section before the conclusion I will describe reasons for having reservations.
Dilatonic Brans-Dicke Anisotropic Collapsing Fluid Sphere And de Broglie Quantum Wave Motion
Hossein Ghaffarnejad
2014-12-18T23:59:59.000Z
Two dimensional analogue of vacuum sector of the Brans Dicke gravity [1] is studied to obtain dynamics of anisotropic spherical symmetric perfect fluid. Solutions of dynamical field equations are obtained in terms of time and radial coordinates. In static regime the obtained solutions leads to a dark matter fluid with state equation $\\gamma=\\frac{p(\\rho)}{\\varrho}=-0.25.$ For non-static regime the fluid can be treat as a regular matter with positive barotropic index $\\gamma>0.$ Evaluation of total mass of the fluid leads to choose particular values on the Brans Dick parameter as $\\omega>\\frac{2}{3};\\omega0$ the apparent horizon is covered by event horizon and hence the cosmic censorship hypothesis is still maintained as valid. \\\\ In second part of the paper we obtain de Broglie pilot wave of our fluid model. It can be describe particles ensemble which are distinguished from each other by $\\omega.$ Incident current density of particles ensemble is evaluated on the event and apparent horizon describing the `Hawking radiation` in statistical mechanics perspective. The quantum potential is calculated on the event horizon which is independent from $\\omega$ but the evaluated quantum potential on the apparent horizon is depended to particular value of $\\omega$.
Conserved Currents in Supersymmetric Quantum Cosmology?
P. V. Moniz
1997-10-20T23:59:59.000Z
In this paper we investigate whether conserved currents can be sensibly defined in supersymmetric minisuperspaces. Our analysis deals with k=1 FRW and Bianchi class--A models. Supermatter in the form of scalar supermultiplets is included in the former. Moreover, we restrict ourselves to the first-order differential equations derived from the Lorentz and supersymmetry constraints. The ``square-root'' structure of N=1 supergravity was our motivation to contemplate this interesting research. We show that conserved currents cannot be adequately established except for some very simple scenarios. Otherwise, conservation equations may only be obtained from Wheeler-DeWitt--like equations, which are derived from the supersymmetric algebra of constraints. Two appendices are included. In appendix A we describe some interesting features of quantum FRW cosmologies with complex scalar fields when supersymmetry is present. In particular, we explain how the Hartle-Hawking state can now be satisfactorily identified. In appendix B we initiate a discussion about the retrieval of classical properties from supersymmetric quantum cosmologies.
The Plasma Puddle as a Perturbative Black Hole
Clifford Cheung; Jared Kaplan
2007-06-07T23:59:59.000Z
We argue that the weak coupling regime of a large N gauge theory in the Higgs phase contains black hole-like objects. These so-called ``plasma puddles'' are meta-stable lumps of hot plasma lying in locally un-Higgsed regions of space. They decay via O(1/N) thermal radiation and, perhaps surprisingly, absorb all incident matter. We show that an incident particle of energy E striking the plasma puddle will shower into an enormous number of decay products whose multiplicity grows linearly with E, and whose average energy is independent of E. Once these ultra-soft particles reach the interior they are thermalized by the plasma within, and so the object appears ``black.'' We determine some gross properties like the size and temperature of the the plasma puddle in terms of fundamental parameters in the gauge theory. Interestingly, demanding that the plasma puddle emit thermal Hawking radiation implies that the object is black (i.e. absorbs all incident particles), which implies classical stability, which implies satisfaction of the Bekenstein entropy bound. Because of the AdS/CFT duality and the many similarities between plasma puddles and black holes, we conjecture that black objects are a robust feature of quantum gravity.
Mass and Free Energy of Lovelock Black Holes
David Kastor; Sourya Ray; Jennie Traschen
2011-06-20T23:59:59.000Z
An explicit formula for the ADM mass of an asymptotically AdS black hole in a generic Lovelock gravity theory is presented, identical in form to that in Einstein gravity, but multiplied by a function of the Lovelock coupling constants and the AdS curvature radius. A Gauss' law type formula relates the mass, which is an integral at infinity, to an expression depending instead on the horizon radius. This and other thermodynamic quantities, such as the free energy, are then analyzed in the limits of small and large horizon radius, yielding results that are independent of the detailed choice of Lovelock couplings. In even dimensions, the temperature diverges in both limits, implying the existence of a minimum temperature for black holes. The negative free energy of sufficiently large black holes implies the existence of a Hawking-Page transition. In odd dimensions the temperature still diverges for large black holes, which again have negative free energy. However, the temperature vanishes as the horizon radius tends to zero and sufficiently small black holes have positive specific heat.
What local supersymmetry can do for quantum cosmology
P. D. D'Eath
2005-11-08T23:59:59.000Z
The canonical approach to Riemannian quantum gravity is reviewed with reference to local supersymmetry, to the classical boundary-value problem arising from the Hartle-Hawking quantum state, and particularly for (anti-)self-dual geometries. Two examples of the boundary-value problem for the Einstein equations, possibly with a cosmological constant \\Lambda, are treated, both of Bianchi-IX type. These close smoothly in the interior with a NUT or a BOLT. The Hamiltonian approach to general relativity is described using Ashtekar variables; for non-zero \\Lambda and anti-self-dual Weyl tensor, the classical solution corresponds, with the most naive choice of boundary data, to the Chern-Simons functional of the boundary data, the classical action being I_{CS}. Hence, one is led to the corresponding quantum states exp(\\pm I_{CS}). Apparently, the classical solutions have the undesirable feature that, in general, the resulting Riemannian classical geometry, arising from the Hamilton-Jacobi equation, does not close smoothly in the interior. The canonical quantum theory of supergravity is also described, and may lead to very streamlined (finite) calculations of loop amplitudes for N=1 supergravity with gauged supermatter. If one uses Ashtekar/Jacobson variables for canonical supergravity, then again (for \\Lambda\
Is there a problem with quantum wormhole states in N=1 Supergravity?
P. V. Moniz
1995-10-13T23:59:59.000Z
The issue concerning the existence of wormhole states in locally supersymmetric minisuperspace models with matter is addressed. Wormhole states are apparently absent in models obtained from the more general theory of N=1 supergravity with supermatter. A Hartle-Hawking type solution can be found, even though some terms (which are scalar field dependent) cannot be determined in a satisfactory way. A possible cause is investigated here. As far as the wormhole situation is concerned, we argue here that the type of Lagrange multipliers and fermionic derivative ordering used can make a difference. A proposal is made for supersymmetric quantum wormholes to also be invested with a Hilbert space structure, associated with a maximal analytical extension of the corresponding minisuperspace.is concerned, we argue here that the type of Lagrange multipliers and fermionic derivative ordering used can make a difference. A proposal is made for supersymmetric quantum wormholes to also be invested with a Hilbert space structure, associated with a maximal analytical extension of the corresponding minisuperspace.
Energy Transfer between Throats from a 10d Perspective
B. v. Harling; A. Hebecker; T. Noguchi
2008-03-28T23:59:59.000Z
Strongly warped regions, also known as throats, are a common feature of the type IIB string theory landscape. If one of the throats is heated during cosmological evolution, the energy is subsequently transferred to other throats or to massless fields in the unwarped bulk of the Calabi-Yau orientifold. This energy transfer proceeds either by Hawking radiation from the black hole horizon in the heated throat or, at later times, by the decay of throat-localized Kaluza-Klein states. In both cases, we calculate in a 10d setup the energy transfer rate (respectively decay rate) as a function of the AdS scales of the throats and of their relative distance. Compared to existing results based on 5d models, we find a significant suppression of the energy transfer rates if the size of the embedding Calabi-Yau orientifold is much larger than the AdS radii of the throats. This effect can be partially compensated by a small distance between the throats. These results are relevant, e.g., for the analysis of reheating after brane inflation. Our calculation employs the dual gauge theory picture in which each throat is described by a strongly coupled 4d gauge theory, the degrees of freedom of which are localized at a certain position in the compact space.
Large photon productions in a gravitational collapsing
She-Sheng Xue
2003-12-16T23:59:59.000Z
We study a possible gravitational vacuum-effect, in which vacuum-energy variation is due to variation of gravitational field, vacuum state gains gravitational energy and releases it by spontaneous photon emissions. Based on the path-integral representation, we present a general formulation of vacuum transition matrix and energy-momentum tensor of a quantum scalar field theory in curved spacetime. Using analytical continuation of dimensionality of the phase space, we calculate the difference of vacuum-energy densities in the presence and absence of gravitational field. Using the dynamical equation of gravitational collapse, we compute the rate of vacuum state gaining gravitational energy. Computing the transition amplitude from initial vacuum state to final vacuum state in gravitational collapsing process, we show the rate and spectrum of spontaneous photon emissions for releasing gravitational energy. The possible connection of our study to the genuine origin of gamma ray bursts is discussed. We compare our idea with the Schwinger idea for Sonoluminiescence and contrast our scenario with the Hawking effect.
Reversible and irreversible spacetime thermodynamics for general Brans-Dicke theories
Chirco, Goffredo; Eling, Christopher; Liberati, Stefano [SISSA, Via Bonomea 265, 34136 Trieste (Italy); INFN Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy)
2011-01-15T23:59:59.000Z
We derive the equations of motion for Palatini F(R) gravity by applying an entropy balance law TdS={delta}Q+{delta}N to the local Rindler wedge that can be constructed at each point of spacetime. Unlike previous results for metric F(R), there is no bulk viscosity term in the irreversible flux {delta}N. Both theories are equivalent to particular cases of Brans-Dicke scalar-tensor gravity. We show that the thermodynamical approach can be used ab initio also for this class of gravitational theories and it is able to provide both the metric and scalar equations of motion. In this case, the presence of an additional scalar degree of freedom and the requirement for it to be dynamical naturally imply a separate contribution from the scalar field to the heat flux {delta}Q. Therefore, the gravitational flux previously associated to a bulk viscosity term in metric F(R) turns out to be actually part of the reversible thermodynamics. Hence we conjecture that only the shear viscosity associated with Hartle-Hawking dissipation should be associated with irreversible thermodynamics.
Bilinear covariants and spinor fields duality in quantum Clifford algebras
Ab?amowicz, Rafa?, E-mail: rablamowicz@tntech.edu [Department of Mathematics, Box 5054, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Gonçalves, Icaro, E-mail: icaro.goncalves@ufabc.edu.br [Instituto de Matemática e Estatística, Universidade de São Paulo, Rua do Matão, 1010, 05508-090, São Paulo, SP (Brazil); Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil); International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste (Italy)
2014-10-15T23:59:59.000Z
Classification of quantum spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic spinor fields, the duality between spinor and quantum spinor fields can be discussed. Thus, by endowing the underlying spacetime with an arbitrary bilinear form with an antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic spinor fields and deformed bilinear covariants can be constructed. They are thus compared to the classical (non quantum) ones. Classes of quantum spinor fields classes are introduced and compared with Lounesto's spinor field classification. A physical interpretation of the deformed parts and the underlying Z-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity [S. W. Hawking, “The unpredictability of quantum gravity,” Commun. Math. Phys. 87, 395 (1982)]. Here, it is shown further to play a prominent role in the structure of Dirac, Weyl, and Majorana spinor fields, besides the most general flagpoles and flag-dipoles. We introduce a new duality between the standard and the quantum spinor fields, by showing that when Clifford algebras over vector spaces endowed with an arbitrary bilinear form are taken into account, a mixture among the classes does occur. Consequently, novel features regarding the spinor fields can be derived.
Tunneling into black hole, escape from black hole, reflection from horizon and pair creation
V. V. Flambaum
2004-08-05T23:59:59.000Z
Within classical general relativity, a particle cannot reach the horizon of a black hole during a finite time, in the reference frame of an external observer; a particle inside cannot escape from a black hole; and the horizon does not produce any reflection. We argue that these processes may possibly be allowed in the quantum world. It is known that quantum mechanics allows pair creation at the horizon (one particle inside, another particle outside) and Hawking radiation. One can extend this idea to propose other processes. Tunneling of an external particle inside black hole may be produced by the creation of a pair at the horizon, followed by the annihilation of one created particle with the initial particle outside, with the other created particle appearing inside. Escape of a particle from a black hole may result from the creation of a pair, followed by the annihilation of one created particle with the particle inside, with the other created particle appearing outside. The escape may allow the transfer of information to the outside.Finally, the reflection of an external particle from the horizon may be modelled by a combination of the two processes presented above. The relationship between these "pair creation-annihilation'' mechanisms and the "horizon tunneling" calculations [1-5] is discussed.
Stationary bound states of spin-half particles in the Kerr and Kerr-Newman gravitational fields
M. V. Gorbatenko; V. P. Neznamov
2013-11-18T23:59:59.000Z
We prove the possibility of existence of stationary bound states of stationary bound states of spin-half probe particles for the Kerr and Kerr-Newman gravitational fields using Chandrasekhar's Hamiltonian. If the Hilbert condition is satisfied, g_{00}>0, bound states of Dirac particles with a real discrete energy spectrum can exist both for particles outside the surface of the outer ergosphere of the Kerr and Kerr-Newman fields, and for particles under the surface of the inner ergosphere. In this case, the surfaces of the external and internal ergospheres play the role of infinitely high potential barriers. Spin-half quantum-mechanical particles cannot cross the ergosphere surfaces of the Kerr and Kerr-Newman fields. Based on the results of this study, we can assume that there exists a new type of rotating collapsars, for which the Hawking radiation is absent. The results of this study can lead to a revision of some concepts of the standard cosmological model related to the evolution of the universe and interaction of rotating collapsars with surrounding matter.
Higgs Boson Production from Black Holes at the LHC
Gouranga C. Nayak; J. Smith
2006-06-09T23:59:59.000Z
If the fundamental Planck scale is near a TeV, then TeV scale black holes should be produced in proton-proton collisions at the LHC where \\sqrt{s} = 14 TeV. As the temperature of the black holes can be ~ 1 TeV we also expect production of Higgs bosons from them via Hawking radiation. This is a different production mode for the Higgs boson, which would normally be produced via direct pQCD parton fusion processes. In this paper we compare total cross sections and transverse momentum distributions d\\sigma/dp_T for Higgs production from black holes at the LHC with those from direct parton fusion processes at next-to-next-to-leading order and next-to-leading order respectively. We find that the Higgs production from black holes can be larger or smaller than the direct pQCD production depending upon the Planck mass and black hole mass. We also find that d\\sigma/dp_T of Higgs production from black holes increases as a function of p_T which is in sharp contrast with the pQCD predictions where d\\sigma/dp_T decreases so we suggest that the measurement of an increase in d\\sigma/dp_T as p_T increases for Higgs (or any other heavy particle) production can be a useful signature for black holes at the LHC.
Quantum Geometry and Black Holes
G., J Fernando Barbero
2015-01-01T23:59:59.000Z
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...
Milagro limits and HAWC sensitivity for the rate-density of evaporating primordial black holes
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Aune, T.; Ayala Solares, H. A.; et al
2015-04-01T23:59:59.000Z
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ~ 5.0 × 10¹? g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV – TeV energy range. The Milagro high energy observatory, which operated from 2000 tomore »2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.« less
NONE
1996-09-01T23:59:59.000Z
This Remedial Investigation (RI) Report characterizes the nature and extent of contamination, evaluates the fate and transport of contaminants, and assesses risk to human health and the environment resulting from waste disposal and other US Department of Energy (DOE) operations in Bear Creek Valley (BCV). BCV, which is located within the DOE Oak Ridge Reservation (ORR) encompasses multiple waste units containing hazardous and radioactive wastes arising from operations at the adjacent Oak Ridge Y-12 Plant. The primary waste units discussed in this RI Report are the S-3 Site, Oil Landfarm (OLF), Boneyard/Burnyard (BYBY), Sanitary Landfill 1 (SL 1), and Bear Creek Burial Grounds (BCBG). These waste units, plus the contaminated media resulting from environmental transport of the wastes from these units, are the subject of this RI. This BCV RI Report represents the first major step in the decision-making process for the BCV watershed. The RI results, in concert with the follow-on FS will form the basis for the Proposed Plan and Record of Decision for all BCV sites. This comprehensive decision document process will meet the objectives of the watershed approach for BCV. Appendix G contains ecological risks for fish, benthic invertebrates, soil invertebrates, plants, small mammals, deer, and predator/scavengers (hawks and fox). This risk assessment identified significant ecological risks from chemicals in water, sediment, soil, and shallow ground water. Metals and PCBs are the primary contaminants of concern.
Electroweak Vacuum (In)Stability in an Inflationary Universe
Kobakhidze, Archil
2013-01-01T23:59:59.000Z
Recent analysis shows that, if the 125-126 GeV LHC resonance turns out to be the Standard Model Higgs boson, the electroweak vacuum would be a metastable state at 98% C.L. In this paper we argue that, during inflation, the electroweak vacuum can actually be very short-lived, contrary to the conclusion that follows from the flat spacetime analysis. Namely, in the case of a pure Higgs potential the electroweak vacuum decays via the Hawking-Moss transition, which has no flat spacetime analogue. As a result, the Higgs vacuum is unstable, unless the rate of inflation is low enough: $H_{\\rm inf}\\lesssim 10^7-10^{10}$ GeV. Models of inflation with such a low rate typically predict negligible tensor perturbations in the cosmic microwave background radiation (CMBR). This is also true for models in which the perturbations are produced by a curvaton field. We also find that if the effective curvature of the Higgs potential at a local maximum (which may be induced by inflaton-Higgs interactions) is large enough, then the...
Wildlife studies on the Hanford site: 1994 Highlights report
Cadwell, L.L. [ed.
1995-04-01T23:59:59.000Z
The purposes of the project are to monitor and report trends in wildlife populations; conduct surveys to identify, record, and map populations of threatened, endangered, and sensitive plant and animal species; and cooperate with Washington State and federal and private agencies to help ensure the protection afforded by law to native species and their habitats. Census data and results of surveys and special study topics are shared freely among cooperating agencies. Special studies are also conducted as needed to provide additional information that may be required to assess, protect, or manage wildlife resources at Hanford. This report describes highlights of wildlife studies on the Site in 1994. Redd counts of fall chinook salmon in the Hanford Reach suggest that harvest restrictions directed at protecting Snake River salmon may have helped Columbia River stocks as well. The 1994 count (5619) was nearly double that of 1993 and about 63% of the 1989 high of approximately 9000. A habitat map showing major vegetation and land use cover types for the Hanford Site was completed in 1993. During 1994, stochastic simulation was used to estimate shrub characteristics (height, density, and canopy cover) across the previously mapped Hanford landscape. The information provided will be available for use in determining habitat quality for sensitive wildlife species. Mapping Site locations of plant species of concern continued during 1994. Additional sensitive plant species data from surveys conducted by TNC were archived. The 10 nesting pairs of ferruginous hawks that used the Hanford Site in 1993 represented approximately 25% of the Washington State population.
QFT, String Temperature and the String Phase of de Sitter Space-time
Medrano, M R
1999-01-01T23:59:59.000Z
The density of mass levels \\rho(m) and the critical temperature for strings in de Sitter space-time are found. QFT and string theory in de Sitter space are compared. A `Dual'-transform is introduced which relates classical to quantum string lengths, and more generally, QFT and string domains. Interestingly, the string temperature in De Sitter space turns out to be the Dual transform of the QFT-Hawking-Gibbons temperature. The back reaction problem for strings in de Sitter space is addressed selfconsistently in the framework of the `string analogue' model (or thermodynamical approach), which is well suited to combine QFT and string study.We find de Sitter space-time is a self-consistent solution of the semiclassical Einstein equations in this framework. Two branches for the scalar curvature R(\\pm) show up: a classical, low curvature solution (-), and a quantum high curvature solution (+), enterely sustained by the strings. There is a maximal value for the curvature R_{\\max} due to the string back reaction. Int...
A novel approach to particle production in an uniform electric field
K. Srinivasan; T. Padmanabhan
1999-11-07T23:59:59.000Z
We outline a different method of describing scalar field particle production in a uniform electric field. In the standard approach, the (analytically continued) harmonic oscillator paradigm is important in describing particle production. However, there is another gauge in which the particle production process has striking similarities with the one used to describe Hawking radiation in black holes. The gauge we use to describe the electric field in is the lightcone gauge, so named because the mode functions for a scalar field are found to be singular on the lightcone. We use these modes in evaluating the effective Lagrangian using the proper time technique. The key feature of this analysis is that these modes can be explicitly "normalized" by using the criterion that they reduce to the usual flat space modes in the limit of the electric field tending to zero. We find that the proper time kernel is not the same as the analytically continued oscillator kernel though the effective Lagrangian is the standard result as it should be. We also consider an example of a confined electric field system using the lightcone gauge modes. Our analysis indicates that the Bogolubov coefficients, in taking the limit to the uniform electric field case, are multiplied by energy dependent boundary factors that have not been taken into account before.
Bulk emission of scalars by a rotating black hole
M. Casals; S. R. Dolan; P. Kanti; E. Winstanley
2008-07-17T23:59:59.000Z
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.
Hagedorn String Thermodynamics in Curved Spacetimes and near Black Hole Horizons
Thomas G. Mertens
2015-06-25T23:59:59.000Z
This thesis concerns the study of high-temperature string theory on curved backgrounds, generalizing the notions of Hagedorn temperature and thermal scalar to general backgrounds. Chapter 2 contains a review on string thermodynamics in flat space, setting the stage. Chapters 3 and 4 contain the detailed study of the random walk picture in a general curved background. Chapters 5 and 6 then apply this to Rindler space, the near-horizon approximation of a generic (uncharged) black hole. Chapters 7 and 8 contain a study of the AdS3 and BTZ WZW models where we study the thermal spectrum and the resulting random walk picture that emerges. Chapters 9 and 10 attempt to draw general conclusions from the study of the two specific examples earlier: we draw lessons on string thermodynamics in general and on (perturbative) string thermodynamics around black hole horizons. For the latter, we point out a possible link to the firewall paradox. Finally, chapter 11 contains a detailed discussion on the near-Hagedorn (and high-energy) stress tensor in a generic spacetime, the results of which are applied to provide a description of the Bekenstein-Hawking entropy in terms of long string equilibration.
Massive scalar particle emission from Schwarzschild black holes
Simkins, R.D.
1986-01-01T23:59:59.000Z
A study is undertaken to compute the absorption coefficients (or particle scattering cross-sections) of massive, scalar modes of Hawking radiation emanating from Schwarzschild black holes. This is accomplished using various variable - and constant - stepwise techniques whose results are later compared. All techniques are applied to the initial value problem associated with the system of two first-order ordinary differential equations derived from separating the Klein-Gordon wave equation in a Kerr-Newman geometry into radial and angular second-order differential equations; and all use the same JWKB-approximated starting values and asymptotic forms of the system's solutions. Using the above coefficients, summing over model angular momenta (l) gives luminosity (or total scattering cross-section, sigma) as a function of modal energy (omega) for the spectrum of modal masses (..mu..). Summing over l and integrating over model energies gives total power emission and total number emission rate as function s of model mass. The approach to the problem that is used involves elements both of the thermodynamic and of the scattering pictures of black hole emission. The partial scattering cross sections are compared both with one another and with the previously known massless, scalar field counterparts.
Bisetti, Fabrizio [246 Hesse Hall, Mailstop 1740, Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740 (United States); Chen, J.-Y. [Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720-1740 (United States); Hawkes, Evatt R. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, NSW 2052 (Australia); Chen, Jacqueline H. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-9051 (United States)
2008-12-15T23:59:59.000Z
Homogeneous charge compression ignition (HCCI) engine technology promises to reduce NO{sub x} and soot emissions while achieving high thermal efficiency. Temperature and mixture stratification are regarded as effective means of controlling the start of combustion and reducing the abrupt pressure rise at high loads. Probability density function methods are currently being pursued as a viable approach to modeling the effects of turbulent mixing and mixture stratification on HCCI ignition. In this paper we present an assessment of the merits of three widely used mixing models in reproducing the moments of reactive scalars during the ignition of a lean hydrogen/air mixture ({phi}=0.1, p=41atm, and T=1070 K) under increasing temperature stratification and subject to decaying turbulence. The results from the solution of the evolution equation for a spatially homogeneous joint PDF of the reactive scalars are compared with available direct numerical simulation (DNS) data [E.R. Hawkes, R. Sankaran, P.P. Pebay, J.H. Chen, Combust. Flame 145 (1-2) (2006) 145-159]. The mixing models are found able to quantitatively reproduce the time history of the heat release rate, first and second moments of temperature, and hydroxyl radical mass fraction from the DNS results. Most importantly, the dependence of the heat release rate on the extent of the initial temperature stratification in the charge is also well captured. (author)
Tawfik, A., E-mail: a.tawfik@eng.mti.edu.eg [Egyptian Center for Theoretical Physics (ECTP), MTI University, 11571 Cairo (Egypt)
2013-07-01T23:59:59.000Z
We investigate the impacts of Generalized Uncertainty Principle (GUP) proposed by some approaches to quantum gravity such as String Theory and Doubly Special Relativity on black hole thermodynamics and Salecker-Wigner inequalities. Utilizing Heisenberg uncertainty principle, the Hawking temperature, Bekenstein entropy, specific heat, emission rate and decay time are calculated. As the evaporation entirely eats up the black hole mass, the specific heat vanishes and the temperature approaches infinity with an infinite radiation rate. It is found that the GUP approach prevents the black hole from the entire evaporation. It implies the existence of remnants at which the specific heat vanishes. The same role is played by the Heisenberg uncertainty principle in constructing the hydrogen atom. We discuss how the linear GUP approach solves the entire-evaporation-problem. Furthermore, the black hole lifetime can be estimated using another approach; the Salecker-Wigner inequalities. Assuming that the quantum position uncertainty is limited to the minimum wavelength of measuring signal, Wigner second inequality can be obtained. If the spread of quantum clock is limited to some minimum value, then the modified black hole lifetime can be deduced. Based on linear GUP approach, the resulting lifetime difference depends on black hole relative mass and the difference between black hole mass with and without GUP is not negligible.
Horizon effects with surface waves on moving water
Germain Rousseaux; Philippe Maissa; Christian Mathis; Pierre Coullet; Thomas G. Philbin; Ulf Leonhardt
2010-10-01T23:59:59.000Z
Surface waves on a stationary flow of water are considered, in a linear model that includes the surface tension of the fluid. The resulting gravity-capillary waves experience a rich array of horizon effects when propagating against the flow. In some cases three horizons (points where the group velocity of the wave reverses) exist for waves with a single laboratory frequency. Some of these effects are familiar in fluid mechanics under the name of wave blocking, but other aspects, in particular waves with negative co-moving frequency and the Hawking effect, were overlooked until surface waves were investigated as examples of analogue gravity [Sch\\"utzhold R and Unruh W G 2002 Phys. Rev. D 66 044019]. A comprehensive presentation of the various horizon effects for gravity-capillary waves is given, with emphasis on the deep water/short wavelength case kh>>1 where many analytical results can be derived. A similarity of the state space of the waves to that of a thermodynamic system is pointed out.
Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black Holes
Abdo, A A; Alfaro, R; Allen, B T; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Aune, T; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Gonzalez, J Becerra; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Chen, C; Christopher, G E; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Diaz-Cruz, L; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Harding, J P; Hays, E; Hoffman, C M; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kolterman, B E; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; MacGibbon, J H; Marinelli, A; Marinelli, S S; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; McEnery, J; Torres, E Mendoza; Mincer, A I; Miranda-Romagnoli, P; Moreno, E; Morgan, T; Mostafá, M; Nellen, L; Nemethy, P; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Ruiz-Velasco, E; Ryan, J; Salazar, H; Salesa, F; Sandoval, A; Parkinson, P M Saz; Schneider, M; Shoup, A; Silich, S; Sinnis, G; Smith, A J; Stump, D; Woodle, K Sparks; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Vasileiou, V; Villaseñor, L; Walker, G P; Weisgarber, T; Westerhoff, S; Williams, D A; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H
2014-01-01T23:59:59.000Z
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and can emit all species of fundamental particles thermally. PBHs with initial masses of ~5.0 x 10^14 g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV - TeV energy range, making them candidate Gamma-ray Burst (GRB) progenitors. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma-rays, the Milagro observatory is well suited for a direct search of PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a...
False Vacuum Decay With Gravity in Non-Thin-Wall Limit
Uchida Gen; Misao Sasaki
1999-12-22T23:59:59.000Z
We consider a wave-function approach to the false vacuum decay with gravity and present a new method to calculate the tunneling amplitude under the WKB approximation. The result agrees with the one obtained by the Euclidean path-integral method, but gives a much clearer interpretation of an instanton (Euclidean bounce solution) that dominates the path integral. In particular, our method is fully capable of dealing with the case of a thick wall with the radius of the bubble comparable to the radius of the instanton, thus surpassing the path-integral method whose use can be justified only in the thin-wall and small bubble radius limit. The calculation is done by matching two WKB wave functions, one with the final state and another with the initial state, with the wave function in the region where the scale factor of the metric is sufficiently small compared with the inverse of the typical energy scale of the field potential at the tunneling. The relation of the boundary condition on our wave function for the false vacuum decay with Hartle-Hawking's no-boundary boundary condition and Vilenkin's tunneling boundary condition on the wave function of the universe is also discussed.
NSTX-U Advances in Real-time C++11 on Linux
Erickson, Keith G
2014-04-01T23:59:59.000Z
Programming languages like C and Ada combined with proprietary embedded operating systems have dominated the real-time application space for decades. The new C++11standard includes native, language-level support for concurrency, a required feature for any nontrivial event-oriented real-time software. Threads, Locks, and Atomics now exist to provide the necessary tools to build the structures that make up the foundation of a complex real-time system. The National Spherical Torus Experiment Upgrade (NSTX-U) at the Princeton Plasma Physics Laboratory (PPPL) is breaking new ground with the language as applied to the needs of fusion devices. A new Digital Coil Protection System (DCPS) will serve as the main protection mechanism for the magnetic coils, and it is written entirely in C++11 running on Concurrent Computer Corporation's real-time operating system, RedHawk Linux. It runs over 600 algorithms in a 5 kHz control loop that determine whether or not to shut down operations before physical damage occurs. To accomplish this, NSTX-U engineers developed software tools that do not currently exist elsewhere, including real-time atomic synchronization, real-time containers, and a real-time logging framework. Together with a recent (and carefully configured) version of the GCC compiler, these tools enable data acquisition, processing, and output using a conventional operating system to meet a hard real-time deadline (that is, missing one periodic is a failure) of 200 microseconds.
Black holes in an asymptotically safe gravity theory with higher derivatives
Cai, Yi-Fu [Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918-4, Beijing 100049 (China); Easson, Damien A., E-mail: caiyf@ihep.ac.cn, E-mail: easson@asu.edu [Department of Physics and School of Earth and Space Exploration and Beyond Center, Arizona State University, Tempe, AZ 85287 (United States)
2010-09-01T23:59:59.000Z
We present a class of spherically symmetric vacuum solutions to an asymptotically safe theory of gravity containing high-derivative terms. We find quantum corrected Schwarzschild-(anti)-de Sitter solutions with running gravitational coupling parameters. The evolution of the couplings is determined by their corresponding renormalization group flow equations. These black holes exhibit properties of a classical Schwarzschild solution at large length scales. At the center, the metric factor remains smooth but the curvature singularity, while softened by the quantum corrections, persists. The solutions have an outer event horizon and an inner Cauchy horizon which equate when the physical mass decreases to a critical value. Super-extremal solutions with masses below the critical value correspond to naked singularities. The Hawking temperature of the black hole vanishes when the physical mass reaches the critical value. Hence, the black holes in the asymptotically safe gravitational theory never completely evaporate. For appropriate values of the parameters such stable black hole remnants make excellent dark matter candidates.
Fuzzy bags, Polyakov loop and gauge/string duality
Fen Zuo
2014-09-10T23:59:59.000Z
Confinement in SU($N$) gauge theory is due to the linear potential between colored objects. At short distances, the linear contribution could be considered as the quadratic correction to the leading Coulomb term. Recent lattice data show that such quadratic corrections also appear in the deconfined phase, in both the thermal quantities and the Polyakov loop. These contributions are studied systematically employing the gauge/string duality. "Confinement" in ${\\mathcal N}=4$ SU($N$) Super Yang-Mills (SYM) theory could be achieved kinematically when the theory is defined on a compact space manifold. In the large-$N$ limit, deconfinement of ${\\mathcal N}=4$ SYM on $\\mathbb{S}^3$ at strong coupling is dual to the Hawking-Page phase transition in the global Anti-de Sitter spacetime. Meantime, all the thermal quantities and the Polyakov loop achieve significant quadratic contributions. Similar results can also be obtained at weak coupling. However, when confinement is induced dynamically through the local dilaton field in the gravity-dilaton system, these contributions can not be generated consistently. This is in accordance with the fact that there is no dimension-2 gauge-invariant operator in the boundary gauge theory. Based on these results, we suspect that quadratic corrections, and also confinement, should be due to global or non-local effects in the bulk spacetime.
Primordial black holes from temporally enhanced curvature perturbation
Teruaki Suyama; Yi-Peng Wu; Jun'ichi Yokoyama
2014-06-02T23:59:59.000Z
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.
Shyamoli Chaudhuri
2005-03-02T23:59:59.000Z
This is a self-contained pedagogical review of Polchinski's 1986 analysis from first principles of the Polyakov path integral based on Hawking's zeta function regularization technique for scale-invariant computations in two-dimensional quantum gravity, an approach that can be adapted to any of the perturbative string theories. In particular, we point out the physical significance of preserving both Weyl and global diffeomorphism invariance while taking the low energy field theory limit of scattering amplitudes in an open and closed string theory, giving a brief discussion of some physics applications. We review the path integral computation of the pointlike off-shell closed bosonic string propagator due to Cohen, Moore, Nelson, and Polchinski. The extension of their methodology to the case of the macroscopic loop propagator in an embedding flat spacetime geometry has been given by Chaudhuri, Chen, and Novak. We examine the macroscopic loop amplitude from the perspective of both the target spacetime massive type II supergravity theory, and the boundary state formalism of the worldsheet conformal field theory, clarifying the precise evidence it provides for a Dirichlet (-2)brane, an identification made by Chaudhuri. The appendices contain extensive detail.
Subenoy Chakraborty; Subhajit Saha
2015-07-06T23:59:59.000Z
The paper deals with the mechanism of particle creation in the framework of irreversible thermodynamics. The second order non-equilibrium thermodynamical prescription of Israel and Stewart has been presented with particle creation rate, treated as the dissipative effect. In the background of a flat FRW model, we assume the non-equilibrium thermodynamical process to be isentropic so that the entropy per particle does not change and consequently the dissipative pressure can be expressed linearly in terms of the particle creation rate. Here the dissipative pressure behaves as a dynamical variable having a non-linear inhomogeneous evolution equation and the entropy flow vector satisfies the second law of thermodynamics. Further, using the Friedmann equations and by proper choice of the particle creation rate as a function of the Hubble parameter, it is possible to show (separately) a transition from the inflationary phase to the radiation era and also from matter dominated era to late time acceleration. Also, in analogy to analytic continuation, it is possible to show a continuous cosmic evolution from inflation to late time acceleration by adjusting the parameters. It is found that in the de Sitter phase, the comoving entropy increases exponentially with time, keeping entropy per particle unchanged. Subsequently, the above cosmological scenarios has been described from field theoretic point of view by introducing a scalar field having self interacting potential. Finally, we make an attempt to show the cosmological phenomenon of particle creation as Hawking radiation, particularly during the inflationary era.
Richard Brito; Vitor Cardoso; Paolo Pani
2015-02-25T23:59:59.000Z
Superradiance is a radiation enhancement process that involves dissipative systems. With a 60 year-old history, superradiance has played a prominent role in optics, quantum mechanics and especially in relativity and astrophysics. In General Relativity, black-hole superradiance is permitted by dissipation at the event horizon, that allows for energy, charge and angular momentum extraction from the vacuum, even at the classical level. Black-hole superradiance is intimately connected to the black-hole area theorem, Penrose process, tidal forces and even Hawking radiation, which can be interpreted as a quantum version of black-hole superradiance. Various mechanisms (as diverse as massive fields, magnetic fields, anti-de Sitter boundaries, nonlinear interactions, etc...) can confine the amplified radiation and give rise to strong instabilities. These "black-hole bombs" have applications in searches of dark matter and of physics beyond the Standard Model, are associated to the threshold of formation of new black hole solutions that evade the no-hair theorems, can be studied in the laboratory by devising analog models of gravity, and might even provide a holographic description of spontaneous symmetry breaking and superfluidity through the gauge-gravity duality. This work is meant to provide a unified picture of this multifaceted subject, which was missing in the literature. We focus on the recent developments in the field, and work out a number of novel examples and applications, ranging from fundamental physics to astrophysics.
Mining Energy from a Black Hole by Strings
V. Frolov; D. Fursaev
2001-05-10T23:59:59.000Z
We discuss how cosmic strings can be used to mine energy from black holes. A string attached to the black hole gives rise to an additional channel for the energy release. It is demonstrated that when a string crosses the event horizon, its transverse degrees of freedom are thermally excited and thermal string perturbations propagate along the string to infinity. The internal metric induced on the 2D worldsheet of the static string crossing the horizon describes a 2D black hole. For this reason thermal radiation of string excitations propagating along the string can be interpreted as Hawking radiation of the 2D black hole. It is shown that the rate of energy emission through the string channel is of the same order of magnitude as the bulk radiation of the black hole. Thus, for N strings attached to the black hole the efficiency of string channels is increased by factor N. We discuss restrictions on N which exist because of the finite thickness of strings, the gravitational backreaction and quantum fluctuations. Our conclusion is that the energy emission rate by strings can be increased as compared to the standard emission in the bulk by the factor 10^3 for GUT strings and up to the factor 10^{31} for electroweak strings.
Dionysios Anninos; Georgios Pastras
2008-09-30T23:59:59.000Z
The local and global thermal phase structure for asymptotically anti-de Sitter black holes charged under an abelian gauge group, with both Gauss-Bonnet and quartic field strength corrections, is mapped out for all parameter space. We work in the grand canonical ensemble where the external electric potential is held fixed. The analysis is performed in an arbitrary number of dimensions, for all three possible horizon topologies - spherical, flat or hyperbolic. For spherical horizons, new metastable configurations are exhibited both for the pure Gauss-Bonnet theory as well as the pure higher derivative gauge theory and combinations thereof. In the pure Gauss-Bonnet theory with negative coefficient and five or more spatial dimensions, two locally thermally stable black hole solutions are found for a given temperature. Either one or both of them may be thermally favored over the anti-de Sitter vacuum - corresponding to a single or a double decay channel for the metastable black hole. Similar metastable configurations are uncovered for the theory with pure quartic field strength corrections, as well combinations of the two types of corrections, in three or more spatial dimensions. Finally, a secondary Hawking-Page transition between the smaller thermally favored black hole and thermal anti-de Sitter space is observed when both corrections are turned on and their couplings are both positive.
Generalized second law of thermodynamics on the apparent horizon in modified Gauss-Bonnet gravity
Abdolmaleki, A
2015-01-01T23:59:59.000Z
Modified gravity and generalized second law (GSL) of thermodynamics are interesting topics in the modern cosmology. In this regard, we investigate the GSL of gravitational thermodynamics in the framework of modified Gauss-Bonnet gravity or f(G)-gravity. We consider a spatially FRW universe filled with the matter and radiation enclosed by the dynamical apparent horizon with the Hawking temperature. For two viable f(G) models, we first numerically solve the set of differential equations governing the dynamics of f(G)-gravity. Then, we obtain the evolutions of the Hubble parameter, the Gauss-Bonnet curvature invariant term, the density and equation of state parameters as well as the deceleration parameter. In addition, we check the energy conditions for both models and finally examine the validity of the GSL. For the selected f(G) models, we conclude that both models have a stable de Sitter attractor. The equation of state parameters behave quite similar to those of the LCDM model in the radiation/matter dominat...
Particle absorption by black holes and the generalized second law of thermodynamics
Scott Funkhouser
2010-04-08T23:59:59.000Z
The change in entropy, /DeltaS, associated with the quasi-static absorption of a particle of energy u by a Schwarzschild black hole (ScBH) is approximately (u/T)-s, where T is the Hawking temperature of the black hole and s is the entropy of the particle. Motivated by the statistical interpretation of entropy, it is proposed here that absorption should be suppressed, but not forbidden, when /DeltaSabsorption cross-section to be sensitive to /DeltaS. A purely thermodynamic formulation of the probability for absorption is obtained from the standard relationship between microstates and entropy. If /DeltaS>>1 and s<
Open inflation in the landscape
Daisuke Yamauchi; Andrei Linde; Atsushi Naruko; Misao Sasaki; Takahiro Tanaka
2011-08-11T23:59:59.000Z
Open inflation scenario is attracting a renewed interest in the context of string landscape. Since there are a large number of metastable de Sitter vacua in string landscape, tunneling transitions to lower metastable vacua through the bubble nucleation occur quite naturally. Although the deviation of Omega_0 from unity is small by the observational bound, we argue that the effect of this small deviation on the large angle CMB anisotropies can be significant for tensor-type perturbation in open inflation scenario. We consider the situation in which there is a large hierarchy between the energy scale of the quantum tunneling and that of the slow-roll inflation in the nucleated bubble. If the potential just after tunneling is steep enough, a rapid-roll phase appears before the slow-roll inflation. In this case the power spectrum is basically determined by the Hubble rate during the slow-roll inflation. If such rapid-roll phase is absent, the power spectrum keeps the memory of the high energy density there in the large angular components. The amplitude of large angular components can be enhanced due to the effects of the wall fluctuation mode if the bubble wall tension is small. Therefore, one can construct some models in which the deviation of Omega_0 from unity is large enough to produce measurable effects. We also consider a more general class of models, where the false vacuum decay may occur due to Hawking-Moss tunneling, as well as the models involving more than one scalar field. We discuss scalar perturbations in these models and point out that a large set of such models is already ruled out by observational data, unless there was a very long stage of slow-roll inflation after the tunneling. These results show that observational data allow us to test various assumptions concerning the structure of the string theory potentials and the duration of the last stage of inflation.
Thermodynamics of Black Hole Horizons and Kerr/CFT Correspondence
Bin Chen; Shen-xiu Liu; Jia-ju Zhang
2012-11-02T23:59:59.000Z
In this paper we investigate the thermodynamics of the inner horizon and its implication on the holographic description of the black hole. We focus on the black holes with two physical horizons. Under reasonable assumption, we prove that the first law of thermodynamics of the outer horizon always indicates that of the inner horizon. As a result, the fact that the area product being mass-independent is equivalent to the relation $T_+S_+=T_-S_-$, with $T_\\pm$ and $S_\\pm$ being the Hawking temperatures and the entropies of the outer and inner horizon respectively. We find that the mass-independence of area product breaks down in general Myers-Perry black holes with spacetime dimension $d\\geq6$ and Kerr-AdS black holes with $d\\geq4$. Moreover we discuss the implication of the first laws of the outer and inner horizons on the thermodynamics of the right- and left-moving sectors of dual CFT in Kerr/CFT correspondence. We show that once the relation $T_+S_+=T_-S_-$ is satisfied, the central charges of two sectors must be same. Furthermore from the thermodynamics relations, we read the dimensionless temperatures of microscopic CFT, which are in exact agreement with the ones obtained from hidden conformal symmetry in the low frequency scattering off the black holes, and then determine the central charges. This method works well in well-known cases in Kerr/CFT correspondence, and reproduce successfully the holographic pictures for 4D Kerr-Newman and 5D Kerr black holes. We go on to predict the central charges and temperatures of a possible holographic CFT description dual to 5D doubly rotating black ring.
Comparing quantum black holes and naked singularities
T. P. Singh
2000-12-21T23:59:59.000Z
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.
Estimating Radiological Doses to Predators Foraging in a Low-Level Radioactive Waste Management Area
L.Soholt; G.Gonzales; P.Fresquez; K.Bennett; E.Lopez
2003-03-01T23:59:59.000Z
Since 1957, Los Alamos National Laboratory has operated Area G as its low-level, solid radioactive waste management and disposal area. Although the waste management area is developed, plants, small mammals, and avian and mammalian predators still occupy the less disturbed and revegetated portions of the land. For almost a decade, we have monitored the concentrations of selected radionuclides in soils, plants, and small mammals at Area G. The radionuclides tritium, plutonium-238, and plutonium-239 are regularly found at levels above regional background in all three media. Based on radionuclide concentrations in mice collected from 1994 to 1999, we calculated doses to higher trophic levels (owl, hawk, kestrel, and coyote) that forage on the waste management area. These predators play important functions in the regional ecosystems and are an important part of local Native American traditional tales that identify the uniqueness of their culture. The estimated doses are compared to Department of Energy's interim limit of 0.1 rad/day for the protection of terrestrial wildlife. We used exposure parameters that were derived from the literature for each receptor, including Environmental Protection Agency's exposure factors handbook. Estimated doses to predators ranged from 9E-06 to 2E-04 rad/day, assuming that they forage entirely on the waste management area. These doses are greater than those calculated for predators foraging exclusively in reference areas, but are still well below the interim dose limit. We believe that these calculated doses represent upper-bound estimates of exposure for local predators because the larger predators forage over areas that are much greater than the 63-acre waste management area. Based on these results, we concluded that predators foraging on this area do not face a hazard from radiological exposure under current site conditions.
A quantum peek inside the black hole event horizon
Sumanta Chakraborty; Suprit Singh; T. Padmanabhan
2015-03-14T23:59:59.000Z
We solve the Klein-Gordon equation for a scalar field, in the background geometry of a dust cloud collapsing to form a black hole, everywhere in the (1+1) spacetime: that is, both inside and outside the event horizon and arbitrarily close to the curvature singularity. This allows us to determine the regularized stress tensor expectation value, everywhere in the appropriate quantum state (viz., the Unruh vacuum) of the field. We use this to study the behaviour of energy density and the flux measured in local inertial frames for the radially freely falling observer at any given event. Outside the black hole, energy density and flux lead to the standard results expected from the Hawking radiation emanating from the black hole, as the collapse proceeds. Inside the collapsing dust ball, the energy densities of both matter and scalar field diverge near the singularity in both (1+1) and (1+3) spacetime dimensions; but the energy density of the field dominates over that of classical matter. In the (1+3) dimensions, the total energy (of both scalar field and classical matter) inside a small spatial volume around the singularity is finite (and goes to zero as the size of the region goes to zero) but the total energy of the quantum field still dominates over that of the classical matter. Inside the event horizon, but \\textit{outside} the collapsing matter, freely falling observers find that the energy density and the flux diverge close to the singularity. In this region, even the integrated energy inside a small spatial volume enclosing the singularity diverges. This result holds in both (1+1) and (1+3) spacetime dimensions with a \\emph{milder} divergence for the total energy inside a small region in (1+3) dimensions. These results suggest that the back-reaction effects are significant even in the region \\emph{outside the matter but inside the event horizon}, close to the singularity.
Akbar, M. M. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2010-09-15T23:59:59.000Z
The thermodynamics of Schwarzschild black holes within spherical isothermal cavities in anti-de Sitter (AdS) space is studied for arbitrary dimensions in the semiclassical approximation of the Euclidean path integral of quantum gravity. For such boundary conditions, known classical solutions are a hot AdS and two or no Schwarzschild-AdS depending on whether or not the wall-temperature of the cavity is above or below a minimum value. Earlier work in four dimensions with such boundary conditions showed that the larger and smaller holes have positive and negative specific heats and hence are locally thermodynamically stable and unstable, respectively. The standard area-law of entropy was known to hold too. We derive the area-law for arbitrary dimensions and show that qualitative behavior of local stability remains the same. Then using a careful analysis of the associated Dirichlet boundary-value problem we address global issues. We find that for wall-temperatures above a critical value a phase transition takes hot AdS to the larger Schwarzschild-AdS. The larger hole thus can be globally thermodynamically stable. We find that the smaller the cavity the higher the critical temperature for phase transition is and it always remains above the minimum temperature needed for the classical existence of the holes in that cavity. In the infinite limit of cavity this picture reduces to that considered by Hawking and Page. All these hold for arbitrary dimensions, however the case of five dimensions turns out to be special in that the Dirichlet problem can be solved exactly giving exact analytic expressions for the black-hole masses as functions of boundary variables (cavity-radius and temperature). This makes it possible to compute the on-shell Euclidean action as a function of boundary variables too from which other quantities of interest can be evaluated. In particular, we obtain the minimum temperature (for the holes to exist classically) and the critical temperature (for phase transition) as functions of the cavity-radius in five dimensions.
Drollinger, Harold [DRI; Jones, Robert C [DRI; Bullard, Thomas F [DRI; Ashbaugh, Laurence J [DRI; Griffin, Wayne R
2011-06-01T23:59:59.000Z
This report presents a historical evaluation of the U12n Tunnel on the Nevada National Security Site (NNSS) in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12n Tunnel was one of a series of tunnels used for underground nuclear weapons effects tests in Rainier and Aqueduct Mesas. A total of 22 nuclear tests were conducted in the U12n Tunnel from 1967 to 1992. These tests include Midi Mist, Hudson Seal, Diana Mist, Misty North, Husky Ace, Ming Blade, Hybla Fair, Mighty Epic, Diablo Hawk, Miners Iron, Huron Landing, Diamond Ace, Mini Jade, Tomme/Midnight Zephyr, Misty Rain, Mill Yard, Diamond Beech, Middle Note, Misty Echo, Mineral Quarry, Randsburg, and Hunters Trophy. DTRA sponsored all tests except Tomme and Randsburg which were sponsored by the Lawrence Livermore National Laboratory. Midnight Zephyr, sponsored by DTRA, was an add on experiment to the Tomme test. Eleven high explosive tests were also conducted in the tunnel and included a Stemming Plan Test, the Pre-Mill Yard test, the two seismic Non-Proliferation Experiment tests, and seven Dipole Hail tests. The U12n Tunnel complex is composed of the portal and mesa areas, encompassing a total area of approximately 600 acres (240 hectares). Major modifications to the landscape have resulted from four principal activities. These are road construction and maintenance, mining activities related to development of the tunnel complex, site preparation for activities related to testing, and construction of retention ponds. A total of 202 cultural features were recorded for the portal and mesa areas. At the portal area, features relate to the mining, construction, testing, and general everyday operational support activities within the tunnel. These include concrete foundations for buildings, ventilation equipment, air compressors, communications equipment, mining equipment, rail lines, retention ponds to impound tunnel effluent, and storage containers. Features on the mesa above the tunnel generally relate to tunnel ventilation and cooling, borehole drilling, and data recording facilities. Feature types include concrete foundations, instrument cable holes, drill holes, equipment pads, ventilation shafts, and ventilation equipment. The U12n Tunnel complex is eligible to the National Register of Historic Places under criteria a and c, consideration g of 36 CFR Part 60.4 as a historic landscape. Scientific research conducted at the tunnel has made significant contributions to the broad patterns of our history, particularly in regard to the Cold War era that was characterized by competing social, economic, and political ideologies between the former Soviet Union and the United States. The tunnel also possesses distinctive construction and engineering methods for conducting underground nuclear tests. The Desert Research Institute recommends that the U12n Tunnel area be left in place in its current condition and that the U12n Tunnel historic landscape be included in the NNSS monitoring program and monitored for disturbances or alterations on a regular basis.
A Historical Evaluation of the U12n Tunnel, Nevada National Security Site, Nye County, Nevada Part 1
Drollinger, Harold [DRI; Jones, Robert C [DRI; Bullard, Thomas F [DRI; Ashbaugh, Laurence J [DRI; Griffin, Wayne R [DRI
2011-06-01T23:59:59.000Z
This report presents a historical evaluation of the U12n Tunnel on the Nevada National Security Site (NNSS) in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12n Tunnel was one of a series of tunnels used for underground nuclear weapons effects tests in Rainier and Aqueduct Mesas. A total of 22 nuclear tests were conducted in the U12n Tunnel from 1967 to 1992. These tests include Midi Mist, Hudson Seal, Diana Mist, Misty North, Husky Ace, Ming Blade, Hybla Fair, Mighty Epic, Diablo Hawk, Miners Iron, Huron Landing, Diamond Ace, Mini Jade, Tomme/Midnight Zephyr, Misty Rain, Mill Yard, Diamond Beech, Middle Note, Misty Echo, Mineral Quarry, Randsburg, and Hunters Trophy. DTRA sponsored all tests except Tomme and Randsburg which were sponsored by the Lawrence Livermore National Laboratory. Midnight Zephyr, sponsored by DTRA, was an add on experiment to the Tomme test. Eleven high explosive tests were also conducted in the tunnel and included a Stemming Plan Test, the Pre-Mill Yard test, the two seismic Non-Proliferation Experiment tests, and seven Dipole Hail tests. The U12n Tunnel complex is composed of the portal and mesa areas, encompassing a total area of approximately 600 acres (240 hectares). Major modifications to the landscape have resulted from four principal activities. These are road construction and maintenance, mining activities related to development of the tunnel complex, site preparation for activities related to testing, and construction of retention ponds. A total of 202 cultural features were recorded for the portal and mesa areas. At the portal area, features relate to the mining, construction, testing, and general everyday operational support activities within the tunnel. These include concrete foundations for buildings, ventilation equipment, air compressors, communications equipment, mining equipment, rail lines, retention ponds to impound tunnel effluent, and storage containers. Features on the mesa above the tunnel generally relate to tunnel ventilation and cooling, borehole drilling, and data recording facilities. Feature types include concrete foundations, instrument cable holes, drill holes, equipment pads, ventilation shafts, and ventilation equipment. The U12n Tunnel complex is eligible to the National Register of Historic Places under criteria a and c, consideration g of 36 CFR Part 60.4 as a historic landscape. Scientific research conducted at the tunnel has made significant contributions to the broad patterns of our history, particularly in regard to the Cold War era that was characterized by competing social, economic, and political ideologies between the former Soviet Union and the United States. The tunnel also possesses distinctive construction and engineering methods for conducting underground nuclear tests. The Desert Research Institute recommends that the U12n Tunnel area be left in place in its current condition and that the U12n Tunnel historic landscape be included in the NNSS monitoring program and monitored for disturbances or alterations on a regular basis.