Entanglement from thermal black body radiation
Braun, Daniel
2005-01-01
Two non--interacting quantum systems which couple to a common environment with many degrees of freedom initially in thermal equilibrium can become entangled due to the indirect interaction mediated through this heat bath. I examine here the dynamics of reservoir induced entanglement for a heat bath consisting of a thermal electro--magnetic radiation field, such as black body radiation or the cosmic microwave background, and show how the effect can be understood as result of an effective induc...
Black-body radiation in Tsallis statistics
Some results for the black-body radiation obtained in the context of the q-thermostatistics are analyzed on both thermodynamical and statistical-mechanical levels. Since the thermodynamic potentials can be expressed in terms of Wright's special function a useful asymptotic expansion can be obtained. This expansion allows to consider thermodynamic properties away from the Boltzmann-Gibbs limit q = 1. The role of non-extensivity, q 4 behavior is considered. The application of some approximation schemes widely used in the literature to analyze the cosmic radiation is discussed. (author)
Attractive optical forces from black-body radiation
Sonnleitner, Matthias; Ritsch, Helmut
2013-01-01
Black-body radiation around hot objects induces AC Stark shifts of the energy levels of nearby atoms and molecules. These shifts are roughly proportional to the fourth power of the temperature and induce a force decaying with the third power of the distance from the object's surface. We explicitly calculate the resulting attractive black-body optical dipole force for ground state hydrogen atoms. Surprisingly this force can surpass the repulsive radiation pressure and actually pull the atoms towards the surface with a force stronger than gravity. We exemplify the dominance of the "black-body force" over gravity for hydrogen in a cloud of hot dust particles. These forces, which have been neglected to date, appear highly relevant in various astrophysical scenarios, in particular since analogous results hold for a wide class of broadband radiation sources.
Fermi golden rule for $N$-body systems in a black-body radiation
Ostilli, Massimo
2016-01-01
We review the calculation of the Fermi golden rule for a system of $N$-body dipoles, magnetic or electric, weakly interacting with a black-body radiation. By using the magnetic or electric field-field correlation function evaluated in the 1960s for the black body radiation, we deduce a general formula for the transition rates and study its limiting, fully coherent or fully incoherent, regimes.
Nonlocal Effects in Black Body Radiation
Bremm, G N
2016-01-01
Nonlocal electrodynamics is a formalism developed to include nonlocal effects in the measurement process caused by the non-inertial state of the observers. This theory modifies Maxwell's electrodynamics by eliminating the hypothesis of locality that assumes an accelerated observer simultaneously equivalent to a comoving inertial frame of reference. In this scenario, the transformation between an inertial and accelerated observer is generalized which affects the properties of physical fields. In particular, we analyze how an uniformly accelerated observer perceives a homogeneous and isotropic blackbody radiation. We show that all nonlocal effects are transient and most relevant in the first period of acceleration.
Thermalization of magnetized electrons from black body radiation
We describe an interesting mechanism whereby an electron in a strong magnetic field can have both the parallel and perpendicular motions come into thermal equilibrium with black body radiation. The mechanism does not include any collisions with other particles and can overcome the extreme slowing of thermalization of highly magnetized particles at low temperatures. The mechanism depends upon the magnetic field strength having a spatial variation. We provide results from two example cases. This mechanism could affect the temperatures that can be achieved in experiments devoted to trapping antihydrogen
Yang, Ping; Feng, Xue-Wen; Liang, Wen-Jun; Wu, Kai-Su
2015-02-01
It is the main aim of this paper to investigate the numerical solutions of the inverse black body radiation problems. The inverse black body radiation problem is ill-posed. Using Gaussian-Laguerre integral formula which is a higher accuracy numerical integration formula with less node numbers to approximate the integral item of black body radiation equation, the black radiation equation is converted into a group of lower dimension algebraic equations. To solve the lower dimension algebraic equation, it only needs to use common Tikhonov regularization methods. The regularization parameter is chosen by using L-curve. Our method reduces the complexity of the algorithm, so the operability of our method is enhanced. Numerical results show that our algorithm is simple and effective, and has better calculation accuracy at the same time.
On the thermodynamics of the conversion of partially polarized black-body radiation
Badescu, V.
1992-01-01
This paper considers a model consisting of : (i) a source of partially polarized black-body radiation (the pump), (ii) a thermally radiative or non-radiative ambient sink and (iii) two energy converters. The first converter (RH) transforms the energy of the black-body radiation into heat, while the second one (HW) (which has a non-zero entropy generation rate) uses that heat to produce work. The entropy-generation rates in the two converters are non-negative only when some conditions are sati...
Calogeracos, A
2002-01-01
We address the question of radiation emission from a perfect mirror that starts from rest and follows the trajectory z=-ln(cosht) ad infinitum. We show that a correct derivation of the black body spectrum via the calculation of Bogolubov amplitudes requires consideration of the whole trajectory and not just of its asymptotic part.
We address the question of radiation emission from a perfect mirror that starts from rest and follows the trajectory z=-ln(cosh t) until t→∞. We show that a correct derivation of the black body spectrum via the calculation of the Bogolubov amplitudes requires consideration of the whole trajectory and not just of its asymptotic part. (author)
The black-body radiation inversion problem, its instability and a new universal function set method
The black-body radiation inversion (BRI) problem is ill-posed and requires special techniques to achieve stable solutions. In this Letter, the universal function set method (UFS), is developed in BRI. An improved unique existence theorem is proposed. Asymptotic behavior control (ABC) is introduced. A numerical example shows that practical calculations are possible with UFS
Black-body radiation effects and light shifts in atomic frequency standards
A general method is presented for calculating the higher-order terms of series in powers of the black-body radiation field for the Stark-state wavefunctions, dipole transition matrix elements and corresponding frequency shifts of hyperfine splitting in the ground states for Cs and Rb atoms. A numerical method for calculating the light shifts in Sr atoms is described. It is based on the Green function method for summation over all intermediate states and exact Dirac-Fock wavefunctions for the resonant transitions to the first excited s-, p- and d-states. By comparing the calculated Stark shift with results of measurements employing atomic frequency standards, the black-body radiation effects on the ground state are analysed
Jarzynski equation for the expansion of a relativistic gas and black-body radiation
Nolte, Roman; Engel, Andreas
2009-09-01
Generalizing the work of Lua and Grosberg [R.C. Lua, A.Y. Grosberg, J. Phys. Chem. B 109 (2005) 6805], we verify the validity of the Jarzynski equation for the non-equilibrium expansion of an ideal relativistic gas and black-body radiation, respectively. The upper limit for the speed of the particles allows one to choose the parameters of the problem such that no multiple collisions need to be taken into account. Although related, the two cases considered differ from each other due to the quantum nature of photons. We show that bunching of photons is crucial for the Jarzynski equation to hold.
Irreducible decomposition of Gaussian distributions and the spectrum of black-body radiation
It is shown that the energy of a mode of a classical chaotic field, following the continuous exponential distribution as a classical random variable, can be uniquely decomposed into a sum of its fractional part and of its integer part. The integer part is a discrete random variable (we call it the Planck variable) whose distribution is just the Bose distribution yielding Planck's law of black-body radiation. The fractional part is the 'dark part' represented by the 'dark variable' with a continuous distribution, which is, of course, not observed in the experiments. It is proved that the Bose distribution is infinitely divisible, and the irreducible decomposition of it is given. This means that the Planck variable can be decomposed into an infinite sum of independent binary random variables representing the 'binary photons' (more accurately photo-molecules or photo-multiplets) of energies 2shν with s=0, 1, 2, .... These binary photons follow Fermi statistics. According to our present analysis, the black-body radiation can be viewed as a mixture of statistically and thermodynamically independent fermion gases consisting of 'binary photons'. The binary photons give a natural tool for the dyadic expansion of arbitrary (but not coherent) ordinary photon excitations. It is shown that the binary photons have wave-particle fluctuations of fermions. These fluctuations combine to give the wave-particle fluctuations of the original bosonic photons, expressed by Einstein's fluctuation formula
Black-body radiation shift of atomic energy-levels:The $ (Z \\alpha)^2\\alpha T^2/m $ correction
Zhou, Wanping; Mei, Xuesong; Lu, Jingjun; Qiao, Haoxue
2016-01-01
The next-to-leading order black-body radiation(BBR) shift to atomic energy-levels, namely $ (Z\\alpha)^2\\alpha T^2/m $ correction, was studied by using the nonrelativistic quantum electrodynamics(NRQED). We also estimate the one-loop contribution of quadrupole and the two-loop contributions of BBR-shift of the thermal(real) photon. These corrections have not been investigated before. The order of magnitude BBR-shift indicates the one-loop contribution of quadrupole is stronger than the previou...
B K Sahoo
2014-08-01
We present here an overview of the role of the multipolar black-body radiation (BBR) shifts in the single ion atomic clocks to appraise the anticipated 10-18 uncertainty level. With an attempt to use the advanced technologies for reducing the instrumental uncertainties at the unprecedented low, it is essential to investigate contributions from the higher-order systematics to achieve the ambitious goal of securing the most precise clock frequency standard. In this context, we have analysed contributions to the BBR shifts from the multipolar polarizabilities in a few ion clocks.
We report on electron cooling power measurements in few-layer graphene excited by Joule heating by means of a new setup combining electrical and optical probes of the electron and phonon baths temperatures. At low bias, noise thermometry allows us to retrieve the well known acoustic phonon cooling regimes below and above the Bloch-Grüneisen temperature, with additional control over the phonon bath temperature. At high electrical bias, we show the relevance of direct optical investigation of the electronic temperature by means of black-body radiation measurements. In this regime, the onset of new efficient relaxation pathways involving optical modes is observed. (paper)
Destroying black holes with test bodies
Jacobson, Ted [Center for Fundamental Physics, University of Maryland, College Park, MD 20742-4111 (United States); Sotiriou, Thomas P, E-mail: jacobson@umd.ed, E-mail: T.Sotiriou@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2010-04-01
If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.
Destroying black holes with test bodies
If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.
Black-body radiation shift of atomic energy-levels:The $ (Z \\alpha)^2\\alpha T^2/m $ correction
Zhou, Wanping; Lu, Jingjun; Qiao, Haoxue
2016-01-01
The next-to-leading order black-body radiation(BBR) shift to atomic energy-levels, namely $ (Z\\alpha)^2\\alpha T^2/m $ correction, was studied by using the nonrelativistic quantum electrodynamics(NRQED) at first. This $T^{2}$-dependent correction has not been investigated before, and only contains the contribution of eletric-dipole of thermal photon. In order to study the contribution of multipolar. We estimate the two-loop contributions of BBR-shift by using quantum electrodynamics approach(QED), and find both one-loop and two-loop diagram contribute to the $ (Z\\alpha)^2\\alpha T^2/m $ correction. Integrating the results which are obtained by these two approaches, the $ (Z\\alpha)^2\\alpha T^2/m $ correction we derived is in principle applicable to multi-electron atoms and contains the contribution of multipolar. The order of magnitude BBR-shift indicates this next-to-leading order BBR-shift may be as significant as the leading order in the multi-electron atoms or cold ones.
Gonzalez-Ayala, Julian; Cordero, Rubén; Angulo-Brown, F
2015-01-01
In this work we present the generalization of some thermodynamic properties of the black body radiation (BBR) towards an $n-$dimensional Euclidean space. For this case the Planck function and the Stefan-Boltzmann law have already been given by Landsberg and de Vos and some adjustments by Menon and Agrawal. However, since then no much more has been done on this subject and we believe there are some relevant aspects yet to explore. In addition to the results previously found we calculate the thermodynamic potentials, the efficiency of the Carnot engine, the law for adiabatic processes and the heat capacity at constant volume. There is a region at which an interesting behavior of the thermodynamic potentials arise, maxima and minima appear for the $n-d$ BBR system at very high temperatures and low dimensionality, suggesting a possible application to cosmology. Finally we propose that an optimality criterion in a thermodynamic framework could have to do with the $3-d$ nature of the universe.
Path integrals for the nonrelativistic electron interacting with the black body radiation
Feynman's method to write the polaron free energy as a functional integral is extended to the electron coupled to the radiation field at finite temperature. To actually perform the summation over the Boson degrees of freedom, we use a path-ordered version of the Feynman--Kac--Ito formula. Like in the polaron case, the resulting free energy derives from an action involving a double stochastic integral with respect to the tied-down Brownian motion. This representation is sufficiently explicit to allow us to take first steps towards solving the renormalization problem (removal of the high-energy cutoff). To order e2, the renormalized free energy is determined and is seen to behave like T2 at small temperatures. The thermodynamical effects, although very small in any laboratory, may become considerable when studying end products of stellar evolution such as white dwarfs and neutron stars. copyright 1995 Academic Press, Inc
Kostanovskiy, A. V.; Pronkin, A. A.; Kostanovskiy, I. A.
2014-04-01
A method of depositing a film (under a radiation flux from a high-temperature black-body model) by magnetron sputtering of a graphite target has been implemented. The elemental composition and structure of deposited films have been analyzed by X-ray photoelectron spectroscopy and characteristic electron-energy-loss spectroscopy. The investigations have shown that chemically pure diamond-like films can be formed at a radiation-flux density no less than 1.5 × 10-4 W/m2 in the spectral range of 170-255 nm.
Schiller, Stephan; Bekbaev, Ashat K; Korobov, Vladimir I
2014-01-01
We calculate the DC Stark effect for three molecular hydrogen ions in the non-relativistic approximation. The effect is calculated both in dependence on the rovibrational state and in dependence on the hyperfine state. We discuss special cases and approximations. We also calculate the AC polarisabilities for several rovibrational levels, and therefrom evaluate accurately the black-body radiation shift, including the effects of excited electronic states. The results enable the detailed evaluation of certain systematic shifts of the transitions frequencies for the purpose of ultra-high-precision optical, microwave or radio-frequency spectroscopy in ion traps.
Black Hole Entropy from Entropy of Hawking Radiation
Aghapour, Sajad
2016-01-01
We provide a simple way for calculating the entropy of a Schwarzschild black hole from the entropy of its Hawking radiation. To this end, we show that if a thermodynamic system loses its energy only through the black body radiation, its loss of entropy is always 3/4 of the entropy of the emitted radiation. This proposition enables us to relate the entropy of an evaporating black hole to the entropy of its Hawking radiation. Explicitly, by calculating the entropy of the Hawking radiation emitted in the full period of evaporation of the black hole, we find the Bekenstein-Hawking entropy of the initial black hole.
Zaleski, Daniel P.; Horrocks, Benjamin R.; Walker, Nick
2015-06-01
A new experiment appropriate for both general chemistry and physical chemistry students will be described. The experiment utilizes "pocket size" USB spectrometers (operating in the UV/vis region) coupled with fiber optic cables to record a solar spectrum. A further extension of the experiment involves recording spectra of a light bulb at several voltages (and thus resistances). Using provided software, students can fit black body distributions to their obtained spectra. The software will display the acquired spectrum, a simulation based on their guess temperature, a simulation based on their fit, and OMC2 for both. Students can then compare their results to the known temperature of the sun and the known temperature vs resistance curve of tungsten.
Massive particle radiation from Gibbons-Maeda black hole
Fang Heng-Zhong
2010-01-01
This paper investigated the massive particle radiation from Gibbous-Maeda black hole by using a semi-classical method. The calculations showed that, if the self-gravitation of the radiated particle is taken into account, the radiation spectrum deviates from exact black body spectrum and the rate of tunneling equals precisely the exponent of the difference of the black hole entropies before and after emission. The conclusion supports the viewpoint of information conservation.
A semiclassical approach to the matte black-body
Ramírez-Moreno, M. A.; González-Hernández, S.; Ares de Parga, G.
2015-11-01
In this paper, a semiclassical approach is used to describe a kind of black-body which we will call a matte black-body. Although the frequency energy density of a black-body is deduced using a semiclassical method which includes the electromagnetic reaction force and the quantization of the energy, a phenomenological damping force, as in the explanation of the anomalous dispersion of some fluids, is considered in order to obtain the corresponding frequency energy density of the matte black-body. The concept of emissivity is incorporated into the new body in order to explain the experimental data of the radiation measured in the Earth’s atmosphere. The purpose of this article consists of showing students the applicability of semiclassical approaches in obtaining physical results.
Stereotactic body radiation therapy
Comprehensive an up-to-date account of the physical/technological, biological, and clinical aspects of SBRT. Examines in detail retrospective studies and prospective clinical trials for various organ sites from around the world. Written by world-renowned experts in SBRT from North America, Asia and Europe. Stereotactic body radiation therapy (SBRT) has emerged as an innovative treatment for various primary and metastatic cancers, and the past five years have witnessed a quantum leap in its use. This book provides a comprehensive and up-to-date account of the physical/technological, biological, and clinical aspects of SBRT. It will serve as a detailed resource for this rapidly developing treatment modality. The organ sites covered include lung, liver, spine, pancreas, prostate, adrenal, head and neck, and female reproductive tract. Retrospective studies and prospective clinical trials on SBRT for various organ sites from around the world are examined, and toxicities and normal tissue constraints are discussed. This book features unique insights from world-renowned experts in SBRT from North America, Asia, and Europe. It will be necessary reading for radiation oncologists, radiation oncology residents and fellows, medical physicists, medical physics residents, medical oncologists, surgical oncologists, and cancer scientists.
Stereotactic body radiation therapy
Lo, Simon S. [Univ. Hospitals Seidman Cancer Center, Cleveland, OH (United States). Dept. of Radiation Oncology; Case Western Reserve Univ., Cleveland, OH (United States). Case Comprehensive Cancer Center; Teh, Bin S. [The Methodist Hospital Cancer Center and Research Institute, Houston, TX (United States). Weill Cornell Medical College; Lu, Jiade J. [National Univ. of Singapore (Singapore). Dept. of Radiation Oncology; Schefter, Tracey E. (eds.) [Colorado Univ., Aurora, CO (United States). Dept. of Radiation Oncology
2012-11-01
Comprehensive an up-to-date account of the physical/technological, biological, and clinical aspects of SBRT. Examines in detail retrospective studies and prospective clinical trials for various organ sites from around the world. Written by world-renowned experts in SBRT from North America, Asia and Europe. Stereotactic body radiation therapy (SBRT) has emerged as an innovative treatment for various primary and metastatic cancers, and the past five years have witnessed a quantum leap in its use. This book provides a comprehensive and up-to-date account of the physical/technological, biological, and clinical aspects of SBRT. It will serve as a detailed resource for this rapidly developing treatment modality. The organ sites covered include lung, liver, spine, pancreas, prostate, adrenal, head and neck, and female reproductive tract. Retrospective studies and prospective clinical trials on SBRT for various organ sites from around the world are examined, and toxicities and normal tissue constraints are discussed. This book features unique insights from world-renowned experts in SBRT from North America, Asia, and Europe. It will be necessary reading for radiation oncologists, radiation oncology residents and fellows, medical physicists, medical physics residents, medical oncologists, surgical oncologists, and cancer scientists.
The relativistic one-loop and two-loop black-body radiation shift of atomic energy-levels
Zhou, Wanping; Mei, Xuesong; Qiao, Haoxue
2016-01-01
The thermal relativistic one-loop and two-loop self-energy corrections of atomic energy-levels induced by the blackbody radiation(BBR) are studied. We estimated the magnitude of BBR-shift of this results in the hydrogen-like atom. The order of magnitude indicated the two loop correction of the real photon is feeble, but that thermal relativistic one-loop self-energy correction and the thermal two-loop self-energy corrections induced by real and virtual photon are abnormal high, which may exce...
The relativistic one-loop and two-loop black-body radiation shift of atomic energy-levels
Zhou, Wanping; Qiao, Haoxue
2016-01-01
The thermal relativistic one-loop and two-loop self-energy corrections of atomic energy-levels induced by the blackbody radiation(BBR) are studied. We estimated the magnitude of BBR-shift of this results in the hydrogen-like atom. The order of magnitude indicated the two loop correction of the real photon is feeble, but that thermal relativistic one-loop self-energy correction and the thermal two-loop self-energy corrections induced by real and virtual photon are abnormal high, which may exceed the leading order correction of BBR in the hydrogen with high $Z$ or low $T$.
Dark Spinors Hawking Radiation in String Theory Black Holes
R. T. Cavalcanti
2016-01-01
Full Text Available The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, which are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.
Dark Spinors Hawking Radiation in String Theory Black Holes
Cavalcanti, R. T.; Roldão da Rocha
2016-01-01
The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, which are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard...
Scalar field radiation from dilatonic black holes
Gohar, H.; Saifullah, K.
2012-12-01
We study radiation of scalar particles from charged dilaton black holes. The Hamilton-Jacobi method has been used to work out the tunneling probability of outgoing particles from the event horizon of dilaton black holes. For this purpose we use WKB approximation to solve the charged Klein-Gordon equation. The procedure gives Hawking temperature for these black holes as well.
The thermal radiation from dynamic black holes
2008-01-01
Using the related formula of dynamic black holes, the instantaneous radiation energy density of the general spherically symmetric charged dynamic black hole and the arbitrarily accelerating charged dynamic black hole is calculated. It is found that the instantaneous radiation energy density of black hole is always proportional to the quartic of the temperature of event horizon in the same direction. The proportional coefficient of generalized Stefan-Boltzmann is no longer a constant, and it becomes a dynamic coefficient that is related to the event horizon changing rate, space-time structure near event horizon and the radiation absorption coefficient of the black hole. It is shown that there should be an internal relation between the gravitational field around black hole and its thermal radiation.
Radiation background of Black Sea coastal environment
The main objective of the project is to establish the level of radiation background and its sources in the Black Sea coastal environment. Marine samples will be collected in the Black Sea Coast area. The content of different radionuclides will be analyzed and the results will be used in a GIS application. The gamma emitting radionuclides will be measured in ultralow radiation background in the Romanian underground laboratory in salt mine in Slanic-Prahova. The main expected results is an up to date quantification of the radiation sources of the background of the Black Sea coastal environment. (authors)
Quantum Radiation of General Nonstationary Black Holes
Hua, Jia-Chen; Huang, Yong-chang
2006-01-01
This paper has been withdrawn by the authors. Quantum radiative characteristics of 4D semi-classical nonstationary black holes in the general case are investigated by using the method of generalized tortoise coordinate transformation. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we discover that there is a certain relationship that is ignored before between thermal radiation and...
Is Radiation of Quantized Black Holes Observable?
Khriplovich, I. B.; Produit, N.
2006-01-01
If primordial black holes (PBH) saturate the present upper limit on the dark matter density in our Solar system and if their radiation spectrum is discrete, the sensitivity of modern detectors is close to that necessary for detecting this radiation. This conclusion is not in conflict with the upper limits on the PBH evaporation rate.
Hawking radiation without black hole entropy
Visser, M
1998-01-01
In this Letter I point out that Hawking radiation is a purely kinematic effect that is generic to Lorentzian geometries. Hawking radiation arises for any test field on any Lorentzian geometry containing an event horizon regardless of whether or not the Lorentzian geometry satisfies the dynamical Einstein equations of general relativity. On the other hand, the classical laws of black hole mechanics are intrinsically linked to the Einstein equations of general relativity (or their perturbative extension into either semiclassical quantum gravity or string-inspired scenarios). In particular, the laws of black hole thermodynamics, and the identification of the entropy of a black hole with its area, are inextricably linked with the dynamical equations satisfied by the Lorentzian geometry: entropy is proportional to area (plus corrections) if and only if the dynamical equations are the Einstein equations (plus corrections). It is quite possible to have Hawking radiation occur in physical situations in which the laws...
Black holes radiate mainly on the brane.
Emparan, R; Horowitz, G T; Myers, R C
2000-07-17
We examine the evaporation of a small black hole on a brane in a world with large extra dimensions. Since the masses of many Kaluza-Klein modes are much smaller than the Hawking temperature of the black hole, it has been claimed that most of the energy is radiated into these modes. We show that this is incorrect. Most of the energy goes 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. PMID:10991325
Gravitational radiation from dynamical black holes
Hayward, Sean A.
2005-01-01
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 ...
Quantum black hole and Hawking radiation at microscopic magnifying
Kiselev, V. V.
2005-01-01
We establish a state of stopping the Hawking radiation by quantum Schwarzschild black hole in the framework of quasi-classical thermal quantization for particles behind the horizon. The mechanism of absorption and radiation by the black hole is presented.
Canonical Ensemble Model for Black Hole Radiation
Jingyi Zhang
2014-09-01
In this paper, a canonical ensemble model for the black hole quantum tunnelling radiation is introduced. In this model the probability distribution function corresponding to the emission shell is calculated to second order. The formula of pressure and internal energy of the thermal system is modified, and the fundamental equation of thermodynamics is also discussed.
Reexamining Black-Body Shifts for Hydrogenlike Ions
Jentschura, U. D.; Haas, M.
2008-01-01
We investigate black-body induced energy shifts for low-lying levels of atomic systems, with a special emphasis on transitions used in current and planned high-precision experiments on atomic hydrogen and ionized helium. Fine-structure and Lamb-shift induced black-body shifts are found to increase with the square of the nuclear charge number, whereas black-body shifts due to virtual transitions decrease with increasing nuclear charge as the fourth power of the nuclear charge. We also investig...
Hawking radiation from rotating brane black holes
Winstanley, Elizabeth(Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom)
2007-01-01
We review recent work on the Hawking radiation of rotating brane black holes, as may be produced at the LHC. We outline the methodology for calculating the fluxes of particles, energy and angular momentum by spin-0, spin-1/2 and spin-1 quantum fields on the brane. We briefly review some of the key features of the emission, in particular the changes in the spectra as the number of extra dimensions or the angular velocity of the black hole increases. These quantities will be useful for accurate...
Accretion radiation from nearby isolated black holes
Recent work attempting to establish the presence of dark matter in the solar neighbourhood has led to renewed interest in the search for the nature of this matter. Previous authors attempt to exclude large (>=2 solar mass) objects by considering their tidal effect on wide binaries. Here independent constraints on such dark massive objects, if they are black holes, are provided by the requirement that their radiation due to accretion from the ISM should not make the nearest ones directly observable as optical objects. The expected infrared brightness is also predicted. It is shown that halo holes must be less massive than about 103 solar masses, and that the dark matter in the galactic disc cannot be made up of black holes of mass more than 10solar masses. Even if black holes do not make up the dark matter, they are expected to be present in the disc as remnants of massive stars. (author)
Orientation to solar radiation in black wildebeest (Connochaetes gnou).
Maloney, Shane K; Moss, Graeme; Mitchell, Duncan
2005-11-01
We recorded the body axis orientation of free-living black wildebeest relative to incident solar radiation and wind. Observations were made on three consecutive days, on six occasions over the course of 1 year, in a treeless, predominantly cloudless habitat. Frequency of orientation parallel to incident solar radiation increased, and perpendicular to incident solar radiation decreased, as ambient dry-bulb temperature or solar radiation intensity increased, or wind speed decreased. We believe these changes were mediated via their effect on skin temperature. Parallel orientation behavior was more prominent when the wildebeest were standing without feeding than it was when they were feeding. We calculate that a black wildebeest adopting parallel orientation throughout the diurnal period would absorb 30% less radiant heat than the same animal adopting perpendicular orientation. Parallel orientation was reduced at times when water was freely available, possibly reflecting a shift from behavioral to autonomic thermoregulatory mechanisms. The use of orientation behavior by black wildebeest is well developed and forms part of the suite of adaptations that help them to maintain heat balance while living in a shadeless, often hot, environment. PMID:16075268
Anomaly and Hawking radiation from regular black holes
Kim, Wontae; Shin, Hyeonjoon; Yoon, Myungseok
2008-01-01
We consider the Hawking radiation from two regular black holes, the minimal model and the noncommutative black hole. The flux of Hawking radiation is derived by applying the anomaly cancellation method proposed by Robinson and Wilczek. Two regular black holes have the same radiation pattern except for the detailed expression for the Hawking temperature. The resulting flux of the energy-momentum tensor is shown to be precisely the same with the thermal flux from each regular black hole at the ...
Black hole formation by incoming electromagnetic radiation
I revisit a known solution of the Einstein field equations to show that it describes the formation of non-spherical black holes by the collapse of pure electromagnetic monochromatic radiation. Both positive and negative masses are feasible without ever violating the dominant energy condition. The solution can also be used to model the destruction of naked singularities and the evaporation of white holes by emission or reception of light. (note)
Kyasov, A. A.; Dedkov, G. V.
2015-01-01
We have developed a self-consistent description of the radiation heat transfer and dynamics of large perfectly black spherical bodies with sizes much greater than the characteristic wavelength of radiation moving in a photon gas with relativistic velocity. The results can be important in astrophysics.
Dynamical Casimir effect and the black body spectrum
Creation of scalar massless particles in two-dimensional Minkowski space time-as predicted by the dynamical Casimir effect-is studied for the case of a semitransparent mirror initially at rest, then accelerating for some finite time, along a specified trajectory, and finally moving with constant velocity. When the reflection and transmission coefficients are those in the model proposed by Barton, Calogeracos and Nicolaevici [r(w) = -iα/(ω + iα) and s(w) = ω/(ω + iα), with α ≥ 0], the Bogoliubov coefficients on the back side of the mirror can be computed exactly. This allows us to prove that, when α is very large (case of an ideal, perfectly reflecting mirror) a thermal emission of scalar massless particles obeying Bose-Einstein statistics is radiated from the mirror (a black body radiation), in accordance with previous results in the literature. However, when α is finite (semitransparent mirror, a physically realistic situation) the striking result is obtained that the thermal emission of scalar massless particles obeys Fermi-Dirac statistics. Possible consequences of this result are envisaged. (fast track communication)
Cutoffs, Stretched Horizons and Black Hole Radiators
Kaloper, Nemanja
2012-01-01
We argue that if the UV cutoff of the IR theory is of the order, or below, the scale of the stretched horizon in a black hole background, which in turn is significantly lower than the Planck scale, the black hole radiance is controlled by the UV completion of the field theory. In particular, if the UV completion of the theory involves degrees of freedom which cannot be efficiently emitted by the black hole, the naive radiance rate estimated by the counting of the IR degrees of freedom may be dramatically reduced. If we apply this argument to the RS2 brane world, it implies that the emission rates of the low energy CFT modes will be dramatically suppressed: its UV completion is given by the bulk gravity on $AdS_5 \\times S^5$, and the only bulk modes that could be emitted by a black hole are the s-waves of bulk modes with small 4D masses. But their emission is suppressed by bulk warping. This lowers the radiation rate much below the IR estimate, by at least a factor of $N \\simeq M_{Pl}^2 L^2$, and follows direc...
Non-thermal Hawking radiation from the Kerr black hole
HAN Yi-Wen; HAO Jia-Bo
2009-01-01
We present a short and direct derivation of Hawking radiation by using the Damour-Ruffini method, as taking into account the self-gravitational interaction from the Kerr black hole. It is found that the radiation is not exactly thermal, and because the derivation obeys conservation laws, the non-thermal Hawking radiation can carry information from the black hole. So it can be used to explain the black hole information paradox, and the process satisfies unitary.
Holley-Bockelmann, Kelly; Dunn, Glenna; Bellovary, Jillian M.; Christensen, Charlotte
2016-01-01
Luminous quasars detected at redshifts z > 6 require that the first black holes form early and grow to ~109 solar masses within one Gyr. Our work uses cosmological simulations to study the formation and early growth of direct collapse black holes. In the pre-reionization epoch, molecular hydrogen (H2) causes gas to fragment and form Population III stars, but Lyman-Werner radiation can suppress H2 formation and allow gas to collapse directly into a massive black hole. The critical flux required to inhibit H2 formation, Jcrit, is hotly debated, largely due to the uncertainties in the source radiation spectrum, H2 self-shielding, and collisional dissociation rates. Here, we test the power of the direct collapse model in a non-uniform Lyman-Werner radiation field, using an updated version of the SPH+N-body tree code Gasoline with H2 non-equilibrium abundance tracking, H2 cooling, and a modern SPH implementation. We vary Jcrit from 30 to 104 J21 to study the effect on seed black holes, focusing on black hole formation as a function of environment, halo mass, metallicity, and proximity of the Lyman-Werner source. We discuss the constraints on massive black hole occupation fraction in the quasar epoch, and implications for reionization, high-redshift X-ray background radiation, and gravitational waves.
Numerical models of black body dominated GRBs: II. Emission properties
Cuesta-Martínez, Carlos F; Mimica, Petar; Thöne, Christina C; de Ugarte-Postigo, Antonio
2014-01-01
We extend an existing theoretical model to explain the class of Black-Body Dominated (BBD) gamma-ray bursts (GRBs), long lasting events characterized by the presence of a significant thermal component trailing the GRB prompt emission, and also by an absence of a traditional afterglow. GRB 101225A, the Christmas Burst, is a prototype of such class. It has been suggested that BBD-GRBs could be observed after a merger in a binary system consisting of a neutron star and a Helium core of a main sequence star. Using detailed relativistic hydrodynamic numerical simulations we model the propagation of ultrarelativistic jets through the environments created by such mergers. In this paper we focus on explaining the emission properties of the jet evolution computing the whole radiative signature (both thermal and non-thermal) of the jet dynamical evolution. A comprehensive parameter study of the jet/environment interaction has been performed and synthetic spectra and light curves are compared with the observational data...
Gravitational Radiation Characteristics of Nonspinning Black-Hole Binaries
Kelly, Barnard
2008-01-01
"We present a detailed descriptive analysis of the gravitational radiation from binary mergers of non-spinning black holes, based on numerical relativity simulations of systems varying from equal-mass to a 6:1 mass ratio. Our analysis covers amplitude and phase characteristics of the radiation, suggesting a unified picture of the waveforms' dominant features in terms of an implicit rotating source. applying uniformly to the full wavetrain, from inspiral through ringdown. We construct a model of the late-stage frequency evolution that fits the $\\ell = m$ modes, and identify late-time relationships between waveform frequency and amplitude. These relationships allow us to construct a predictive model for the late-time waveforms, an alternative to the common practice of modelling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model."
Gravitational radiation characteristics of nonspinning black-hole binaries
Kelly, B J; Baker, J G; Boggs, W D; Centrella, J M; Meter, J R van; McWilliams, S T, E-mail: bernard.j.kelly@nasa.go, E-mail: john.g.baker@nasa.go, E-mail: william.d.boggs@nasa.go, E-mail: joan.m.centrella@nasa.go, E-mail: james.r.vanmeter@nasa.go, E-mail: sean.t.mcwilliams@nasa.go [NASA Goddard Space Flight Center, Greenbelt MD 20771 (United States)
2009-03-01
We present a detailed descriptive analysis of the gravitational radiation from binary mergers of non-spinning black holes, based on numerical relativity simulations of systems varying from equal-mass to a 6:1 mass ratio. Our analysis covers amplitude and phase characteristics of the radiation, suggesting a unified picture of the waveforms' dominant features in terms of an implicit rotating source, applying uniformly to the full wavetrain, from inspiral through ringdown. We construct a model of the late-stage frequency evolution that fits the l = m modes, and identify late-time relationships between waveform frequency and amplitude. These relationships allow us to construct a predictive model for the late-time waveforms, an alternative to the common practice of modelling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.
Gravitational radiation characteristics of nonspinning black-hole binaries
We present a detailed descriptive analysis of the gravitational radiation from binary mergers of non-spinning black holes, based on numerical relativity simulations of systems varying from equal-mass to a 6:1 mass ratio. Our analysis covers amplitude and phase characteristics of the radiation, suggesting a unified picture of the waveforms' dominant features in terms of an implicit rotating source, applying uniformly to the full wavetrain, from inspiral through ringdown. We construct a model of the late-stage frequency evolution that fits the l = m modes, and identify late-time relationships between waveform frequency and amplitude. These relationships allow us to construct a predictive model for the late-time waveforms, an alternative to the common practice of modelling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.
Tidal interaction of black holes and Newtonian viscous bodies
Poisson, Eric
2009-01-01
The tidal interaction of a (rotating or nonrotating) black hole with nearby bodies produces changes in its mass, angular momentum, and surface area. Similarly, tidal forces acting on a Newtonian, viscous body do work on the body, change its angular momentum, and part of the transferred gravitational energy is dissipated into heat. The equations that describe the rate of change of the black-hole mass, angular momentum, and surface area as a result of the tidal interaction are compared with the equations that describe how the tidal forces do work, torque, and produce heat in the Newtonian body. The equations are strikingly similar, and unexpectedly, the correspondence between the Newtonian-body and black-hole results is revealed to hold in near-quantitative detail. The correspondence involves the combination k_2 \\tau of ``Love quantities'' that incorporate the details of the body's internal structure; k_2 is the tidal Love number, and \\tau is the viscosity-produced delay between the action of the tidal forces a...
Redshifting of cosmological black bodies in BSBM varying-alpha theories
Barrow, John D
2014-01-01
We analyse the behaviour of black-body radiation in theories of electromagnetism which allow the electron charge and the fine structure constant to vary in space and time. We show that such theories can be expressed as relativistic generalizations of a conventional dielectric. By making the appropriate definition of the vector potential and associated gauge transformations, we can identify the equivalent of the electric and displacement fields, $\\mathbf{E}$ and $\\mathbf{D}$, as well as the magnetic $ \\mathbf{B}$ and $\\mathbf{H}$ fields. We study the impact of such dielectrics on the propagation of light in the so-called BSBM theory and conclude that no changes are created to the standard cosmological evolution of the temperature and energy-density of black-body radiation.
Black-body laws derived from a minimum knowledge of Physics
A. G. AgneseINFN; La Camera, M.; E. Recami(INFN)
2015-01-01
Starting from the knowledge of the four fundamental quantities length L, mass M, time T, absolute temperature $\\theta$ and accepting the validity of Gauss's law in all dimensions, we generalize, by the theory of physical dimensions, the expression of the Stephan-Boltzmann law and of the Planck's formula for the black-body radiation to a spacetime with one time and n spatial coordinates. In the particular case n=3 we shall recover the known results.
Hawking radiation from covariant anomalies in (2+1)-dimensional black holes
In an insightful approach, Robinson and Wilczek proposed that Hawking radiation can be obtained as the compensation of a breakdown of general covariance and gauge invariance and the radiation is a black body radiation at Hawking temperature. We apply this method to two types of black holes in three-dimensional spacetime, both of which have the form of a metric such that the tt component of the metric is not inverse of the rr component of the metric. The first one is the warped AdS3 black hole in three-dimensional topologically massive gravity with the negative cosmological constant, and the second one is the charged rotating black hole in three dimensions.
Radiation spectrum of a high-dimensional rotating black hole
无
2010-01-01
This study extends the classical Damour-Ruffini method and discusses Hawking radiation in a (n + 4)-dimensional rotating black hole. Under the condition that the total energy and angular momentum of spacetime are conservative, but angular momentum a = J/M of unit mass of the black hole is variable, taking into consideration the reaction of the radiation of the particle to the spacetime, a new Tortoise coordinate transformation and discuss the black hole radiation spectrum is discussed. The radiation spectrum that satisfies the unitary principle in the general case is derived.
Hawking radiation from a five-dimensional Lovelock black hole
Saleh, Mahamat; Crepin, Kofane Timoleon
2016-01-01
We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological constant. Moreover, the presence of the cosmological constant makes the effect of the ultraviolet correction on the black hole radiation negligible.
Hawking radiation from a five-dimensional Lovelock black hole
Saleh, Mahamat; Thomas, Bouetou Bouetou; Kofane, Timoleon Crepin
2015-10-01
We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological constant. Moreover, the presence of the cosmological constant makes the effect of the ultraviolet correction on the black hole radiation negligible.
UV radiation impairs the body's defence mechanism
Ultraviolet (UV) radiation is usually divided into three wavelength ranges, which differ considerably from each other with respect to their effect on human health. UV-B radiation, in particular, weakens the body's resistance against cancer cells and thus increases cancer risk. Although virtually all UV-B radiation stops at the surface layer of skin, the whole body suffers from its adverse effects. UV radiation affects the body's defence mechanism relatively quickly. A reduction in the body's capacity to defend itself against alien substances can already be detected within a couple of days after the body has been exposed to a small amount of UV radiation. The risk of cancer increases slowly over the years. The skin cancers that are treated in hospitals today have their origin in the ways of life pursued in the 1960's and 70's. Factors affecting the amounts of UV doses received by Finns include trips to the South, solarium treatments and, to some extent, thinning of the ozone layer. (orig.) (4 figs.)
Tunneling Radiation of Massive Vector Bosons from Dilaton Black Holes
Li, Ran; Zhao, Jun-Kun; Wu, Xing-Hua
2016-07-01
It is well known that Hawking radiation can be treated as a quantum tunneling process of particles from the event horizon of black hole. In this paper, we attempt to apply the massive vector bosons tunneling method to study the Hawking radiation from the non-rotating and rotating dilaton black holes. Starting with the Proca field equation that govern the dynamics of massive vector bosons, we derive the tunneling probabilities and radiation spectrums of the emitted vector bosons from the static spherical symmetric dilatonic black hole, the rotating Kaluza—Klein black hole, and the rotating Kerr—Sen black hole. Comparing the results with the blackbody spectrum, we satisfactorily reproduce the Hawking temperatures of these dilaton black holes, which are consistent with the previous results in the literature. Supported by National Natural Science Foundation of China under Grant No. 11205048
Hawking Radiation from Higher-Dimensional Black Holes
Kanti, Panagiota; Winstanley, Elizabeth(Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom)
2014-01-01
We review the quantum field theory description of Hawking radiation from evaporating black holes and summarize what is known about Hawking radiation from black holes in more than four space-time dimensions. In the context of the Large Extra Dimensions scenario, we present the theoretical formalism for all types of emitted fields and a selection of results on the radiation spectra. A detailed analysis of the Hawking fluxes in this case is essential for modelling the evaporation of higher-dimen...
Hawking radiation from a five-dimensional Lovelock black hole
Saleh, Mahamat; Thomas, Bouetou Bouetou; Crepin, Kofane Timoleon
2016-01-01
We investigate Hawking radiation from a five-dimensional Lovelock black hole using the Hamilton-Jacobi method. The behavior of the rate of radiation is plotted for various values of the ultraviolet correction parameter and the cosmological constant. The results show that, owing to the ultraviolet correction and the presence of dark energy represented by the cosmological constant, the black hole radiates at a slower rate in comparison to the case without ultraviolet correction or cosmological ...
The Black Body and Representations of the (In)human
Hsiao, Li-Chun
2007-01-01
Li-Chun Hsiao, in his article "The Black Body and Representations of the (In)human," takes cues from the theoretical insights of Agamben's "bare life" as well as Laclau's and Mouffe's "social antagonism" and explores how the slave can be considered a constitutive element which is nevertheless foreclosed from Western democracies. Hsiao also analyzes the various ways the term "slave" functions as trope in the founding discourses of Western democracy. "Bare life" remains included in politics "in...
Characteristics of Quantum Radiation of General Nonstationary Black Holes
Hua, J C; Hua, Jia-Chen; Huang, Yong-Chang
2006-01-01
Quantum radiative characteristics of general nonstationary black holes in the general case are investigated by using the method of generalized tortoise coordinate transformation. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we discover that there is a certain relationship that is ignored before between thermal radiation and non-thermal radiation of black holes, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of particles in non-thermal radiation for slowly varying nonstationary black holes. Also, we show that the deduced general results can be applied to different concrete conditions.
Quantum Radiation of Dirac Particles in General Nonstationary Black Holes
Hua, J C; Hua, Jia-Chen; Huang, Yong-Chang
2006-01-01
Quantum radiation of Dirac particles in general nonstationary black holes in the general case is investigated by using the method of generalized tortoise coordinate transformation and considering simultaneously the asymptotic behaviors of the first order and second order forms of Dirac equation near the event horizon. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we give a general expression of the new extra coupling effect in thermal radiation spectrum of Dirac particles which is absent from the thermal radiation spectrum of scalar particles. Also, we reveal a relationship that is ignored before between thermal radiation and non-thermal radiation in the case of scalar particles, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of scalar particles in non-thermal radiation for general nonstationary black holes.
Density matrix of radiation of black hole with fluctuating horizon
Iofa, Mikhail Z
2016-01-01
The density matrix of Hawking radiation is calculated in the model of black hole with fluctuating horizon. Quantum fluctuations smear the classical horizon of black hole and modify the density matrix of radiation producing the off-diagonal elements. The off-diagonal elements may store information of correlations between radiation and black hole. The smeared density matrix was constructed by convolution of the density matrix calculated with the instantaneous horizon with the Gaussian distribution over the instantaneous horizons. The distribution has the extremum at the classical radius of the black hole and the width of order of the Planck length. Calculations were performed in the model of black hole formed by the thin collapsing shell which follows a trajectory which is a solution of the matching equations connecting the interior and exterior geometries.
The fate of radiating black holes in noncommutative geometry
Piero NicoliniStefan I., Ljubljana & Turin Poly. & INFN, Trieste; Anais SmailagicINFN, Trieste; Euro SpallucciTrieste U. & INFN, Trieste
2014-01-01
We investigate the behavior of a radiating Schwarzschild black hole toy-model in a 2D noncommutative spacetime. It is shown that coordinate noncommutativity leads to: i) the existence of a minimal non-zero mass to which black hole can shrink; ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing terminal pha...
A model of radiating black hole in noncommutative geometry
Nicolini, Piero
2005-01-01
The phenomenology of a radiating Schwarzschild black hole is analyzed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: i) the existence of a minimal non-zero mass to which black hole can shrink; ii) a finite maximum temperature that the black hole can reach before cooli...
Hawking radiation of Dirac particles from black strings
Ahmed, Jamil; Saifullah, K.
2011-08-01
Hawking radiation has been studied as a phenomenon of quantum tunneling in different black holes. In this paper we extend this semi-classical approach to cylindrically symmetric black holes. Using the Hamilton-Jacobi method and WKB approximation we calculate the tunneling probabilities of incoming and outgoing Dirac particles from the event horizon and find the Hawking temperature of these black holes. We obtain results both for uncharged as well as charged particles.
Hawking radiation of Dirac particles from black strings
Ahmed, Jamil
2011-01-01
Hawking radiation has been studied as a phenomenon of quantum tunneling in different black holes. In this paper we extend this semi-classical approach to cylindrically symmetric black holes. Using the Hamilton-Jacobi method and WKB approximation we calculate the tunneling probabilities of incoming and outgoing Dirac particles from the event horizon and find the Hawking temperature of these black holes. We obtain results both for uncharged as well as charged particles.
Thermal radiation and nonthermal radiation of the slowly changing dynamic Kerr-Newman black hole
Meng Qing-Miao; Wang Shuai; Jiang Ji-Jian; Deng De-Li
2008-01-01
Using the related formula of dynamic black hole, we have calculated the instantaneous radiation energy density of the slowly changing dynamic Kerr-Newman black hole. It is found that the instantaneous radiation energy density of a black hole is always proportional to the quartic of the temperature of the event horizon in the same direction. By using the Hamilton-Jacobin equation of scalar particles in the curved spacetime, the spontaneous radiation of the slowly changing dynamic Kerr-Newman black hole is studied. The energy condition for the occurrence of the spontaneous radiation is obtained.
Possible suppression of Hawking radiation from microscopic black holes
Ahn, Doyeol
2010-01-01
Microscopic black holes with mass in the TeV range to be produced in the Large Hadron Collider (LHC) should undergo the prompt and quasi-thermal evaporation by emitting Hawking radiation. If this Hawking decay is not universal, some black holes can live long enough to penetrate into the Earth and grow dangerously. At present, the effects of black hole internal quantum state evolution on the evaporation are not well understood. This study shows that Hawking decay could be suppressed when the black hole internal matter state is in the coherent state. In this case, black holes created in the LHC may live long enough to grow catastrophically. The condition to avoid this catastrophic situation is also discussed. Our results demonstrate that the black hole evaporation is strongly dependent on the black hole internal quantum state and its evolution.
Hawking Radiation of Grumiller Black Hole
Sakalli, I
2014-01-01
In this paper, we consider the relativistic Hamilton-Jacobi (HJ) equation and study the Hawking radiation (HR) of scalar particles from uncharged Grumiller black hole (GBH) which is affordable for testing in astrophysics. GBH is also known as Rindler modified Schwarzschild BH. Our aim is not only to investigate the effect of the Rindler parameter a on the Hawking temperature ($T_{H}$), but to examine whether there is any discrepancy between the computed horizon temperature and the standard $T_{H}$ as well. For this purpose, in addition to its naive coordinate system, we study on the three regular coordinate systems which are Painleve-Gullstrand (PG), ingoing Eddington-Finkelstein (IEF) and Kruskal-Szekeres (KS) coordinates. In all coordinate systems, we calculate the tunneling probabilities of incoming and outgoing scalar particles from the event horizon by using the HJ equation. It has been shown in detail that the considered HJ method is concluded with the conventional $T_{H}$ in all these coordinate system...
Hawking radiation from acoustic black holes in two space dimensions
Eskin, Gregory
2016-01-01
We study the Hawking radiation from rotating acoustic black hole. We follow the approach of T.Jacobson and W.Unruh, although our approach differs in details. We also treat the case of variable velocity of the background flow.
A Rat Body Phantom for Radiation Analysis
Qualls, Garry D.; Clowdsley, Martha S.; Slaba, Tony C.; Walker, Steven A.
2010-01-01
To reduce the uncertainties associated with estimating the biological effects of ionizing radiation in tissue, researchers rely on laboratory experiments in which mono-energetic, single specie beams are applied to cell cultures, insects, and small animals. To estimate the radiation effects on astronauts in deep space or low Earth orbit, who are exposed to mixed field broad spectrum radiation, these experimental results are extrapolated and combined with other data to produce radiation quality factors, radiation weighting factors, and other risk related quantities for humans. One way to reduce the uncertainty associated with such extrapolations is to utilize analysis tools that are applicable to both laboratory and space environments. The use of physical and computational body phantoms to predict radiation exposure and its effects is well established and a wide range of human and non-human phantoms are in use today. In this paper, a computational rat phantom is presented, as well as a description of the process through which that phantom has been coupled to existing radiation analysis tools. Sample results are presented for two space radiation environments.
Unthermal Hawking Radiation from a General Stationary Black Hole
ZHANG Gui-Qing; ZHANG Yong-Ping; YANG Qiu-Ying; DAI Qian; CHEN Tian-Lun; LIU Wen-Biao
2008-01-01
Using Damour-Ruffini's method, Hawking radiation from a general stationary black hole is investigated again deeply. Considering the back reaction of the particle to the space-time and energy conservation, we find that the radiation is not exactly thermal and can take out information from the black hole. This can be used to explain the information loss paradox, and the result is consistent with the works finished before.
Mergers of nonspinning black-hole binaries: Gravitational radiation characteristics
Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; van Meter, James R.
2008-01-01
We present a detailed descriptive analysis of the gravitational radiation from black-hole binary mergers of nonspinning black holes, based on numerical simulations of systems varying from equal-mass to a 6:1 mass ratio. Our primary goal is to present relatively complete information about the waveforms, including all the leading multipolar components, to interested researchers. In our analysis, we pursue the simplest physical description of the dominant features in the radiation, providing an ...
A model of radiating black hole in noncommutative geometry
Nicolini, Piero [Dipartimento di Matematica e Informatica, Universita di Trieste, Trieste (Italy); Institut Jozef Stefan, Ljubljana (Slovenia); Dipartimento di Matematica, Politecnico di Torino, Turin (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (Italy)
2005-09-30
The phenomenology of a radiating Schwarzschild black hole is analysed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus, we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: (i) the existence of a minimal nonzero mass to which black hole can shrink; (ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; (iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing the terminal phase of black hole evaporation. (letter to the editor)
A model of radiating black hole in noncommutative geometry
The phenomenology of a radiating Schwarzschild black hole is analysed in a noncommutative spacetime. It is shown that noncommutativity does not depend on the intensity of the curvature. Thus, we legitimately introduce noncommutativity in the weak field limit by a coordinate coherent state approach. The new interesting results are the following: (i) the existence of a minimal nonzero mass to which black hole can shrink; (ii) a finite maximum temperature that the black hole can reach before cooling down to absolute zero; (iii) the absence of any curvature singularity. The proposed scenario offers a possible solution to conventional difficulties when describing the terminal phase of black hole evaporation. (letter to the editor)
Tunnelling Effect and Hawking Radiation from a Vaidya Black Hole
ZHANG Jing-Yi; ZHAO Zheng
2006-01-01
@@ We extend Parikh's study to the non-stationary black hole. As an example of the non-stationary black hole, we investigate the tunnelling effect and Hawking radiation from a Vaidya black hole whose Bondi mass is identical to its mass parameter. The Hawking radiation is considered as a tunnelling process across the event horizon and we calculate the tunnelling probability. It is found that the result is different from Parikh's study because drH/dv is the function of Bondi mass m(v).
Black Sun: Ocular Invisibility of Relativistic Luminous Astrophysical Bodies
Lee, Jeffrey S
2015-01-01
The relativistic Doppler shifting of visible electromagnetic radiation to beyond the human ocular range reduces the incident radiance of the source. Consequently, luminous astrophysical bodies (LABs) can be rendered invisible with sufficient relativistic motion. This paper determines the proper distance as a function of relativistic velocity at which a luminous object attains ocular invisibility.
Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)
Cavaglia, Marco
2003-01-01
If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this paper we study some experimental signatures of black hole production in TeV-gravity theories. In contrast with the usual lore, we show that the black hole energy loss in the bulk during the Hawking evaporation phase may be of the same order of the energy radiated into the brane. We investigate in detail the multiplicity of the decay products of black hole evaporation. We fi...
Dilaton Black Hole Tunneling Radiation in de Sitter Universe
LI Gu-Qiang
2009-01-01
The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh-Wilczek's method. We show that if the self-gravitational interaction and energy conservation are taken into account, the modified radiation spectrum deviates from exact thermal spectrum and satisfies the unitary theory.
GUP Assisted Hawking Radiation of Rotating Acoustic Black Holes
Sakalli, I; Jusufi, K
2016-01-01
Recent studies [J. Steinhauer, Nature Phys., $\\textbf{10}$, 864 (2014); Phys. Rev. D $\\textbf{92}$, 024043 (2015)] provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.
Harms, Enno; Bernuzzi, Sebastiano; Nagar, Alessandro
2016-01-01
We consider a spinning test-body in circular motion around a nonrotating black hole and analyze different prescriptions for the body's dynamics. We compare, for the first time, the Mathisson-Papapetrou formalism under the Tulczyjew spin-supplementary-condition (SSC), the Pirani SSC and the Ohashi-Kyrian-Semerak SSC, and the spinning particle limit of the effective-one-body Hamiltonian of [Phys.~Rev.~D.90,~044018(2014)]. We analyze the four different dynamics in terms of the ISCO shifts and in terms of the coordinate invariant binding energies, separating higher-order spin contributions from spin-orbit contributions. The asymptotic gravitational wave fluxes produced by the spinning body are computed by solving the inhomogeneous $(2+1)D$ Teukolsky equation and contrasted for the different cases. For small orbital frequencies $\\Omega$, all the prescriptions reduce to the same dynamics and the same radiation fluxes. For large frequencies, ${x \\equiv (M \\Omega)^{2/3} >0.1 }$, where $M$ is the black hole mass, and ...
Matter flows around black holes and gravitational radiation
Papadopoulos, Philippos; Font, Jose A.
1998-01-01
We develop and calibrate a new method for estimating the gravitational radiation emitted by complex motions of matter sources in the vicinity of black holes. We compute numerically the linearized curvature perturbations induced by matter fields evolving in fixed black hole backgrounds, whose evolution we obtain using the equations of relativistic hydrodynamics. The current implementation of the proposal concerns non-rotating holes and axisymmetric hydrodynamical motions. As first applications...
Applications of geometric algebra to black holes and Hawking radiation
Setiawan, S.
2004-01-01
We discuss the applications of Gauge Theory of Gravity (GTG) within the language of geometric algebra to black holes and Hawking radiation. Applications include the Unruh effect, the Dirac and Klein-Gordon equations in several backgrounds, such as the de Sitter and Rindler metrics as well as spherically and axially black hole backgrounds. The analysis is also generalised to allow the presence of magnetic monopoles. We rederive the Hawking temperature for all cases. The derivation of both the ...
Quantum tunnelling for Hawking radiation from a dynamical Black Hole
Mazumder, Nairwita; Chakraborty, Subenoy
2011-01-01
The paper deals with Hawking radiation related to non-static spherically symmetric black hole. Quantum corrections are incorporated using Hamilton-Jacobi method beyond semi-classical approximation. It is found that different order correction terms satisfy identical differential equation as the semiclassical action and are solved by a typical technique. It has been shown that with proper choice of the proportionality factors, one loop back reaction effect in the space time can be obtained. Finally, using the law of black hole mechanics, a general modified form of the black hole entropy is obtained considering modified Hawking temperature.
Inferring black hole charge from backscattered electromagnetic radiation
Crispino, Luís C B; Higuchi, Atsushi; de Oliveira, Ednilton S
2014-01-01
We compute the scattering cross section of Reissner-Nordstr\\"om black holes for the case of an incident electromagnetic wave. We describe how scattering is affected by both the conversion of electromagnetic to gravitational radiation, and the parity-dependence of phase shifts induced by the black hole charge. The latter effect creates a helicity-reversed scattering amplitude that is non-zero in the backward direction. We show that from the character of the electromagnetic wave scattered in the backward direction it is possible, in principle, to infer if a static black hole is charged.
Hawking radiation of Kerr-Newman black hole in different tortoise coordinate transformations
Ibungochouba Singh, T.
2013-10-01
Hawking radiation effect of Maxwell’s electromagnetic fields in the Kerr-Newman black hole space-time is investigated using two different tortoise coordinate transformations. It has been shown that the new tortoise coordinate transformation produces constant term ξ in the expression of surface gravity and Hawking temperature. If ξ is set to zero, the surface gravity and Hawking temperature will be equal to those obtained from the old tortoise coordinate transformation. This indicates that new transformation is more reliable and accurate. The black body radiant spectrum of photon displays a new spin-rotation coupling effect.
Modeling gravitational radiation from coalescing binary black holes
Baker, J; Loustó, C O; Takahashi, R
2002-01-01
With the goal of bringing theory, particularly numerical relativity, to bear on an astrophysical problem of critical interest to gravitational wave observers we introduce a model for coalescence radiation from binary black hole systems. We build our model using the "Lazarus approach", a technique that bridges far and close limit approaches with full numerical relativity to solve Einstein equations applied in the truly nonlinear dynamical regime. We specifically study the post-orbital radiation from a system of equal-mass non-spinning black holes, deriving waveforms which indicate strongly circularly polarized radiation of roughly 3% of the system's total energy and 12% of its total angular momentum in just a few cycles. Supporting this result we first establish the reliability of the late-time part of our model, including the numerical relativity and close-limit components, with a thorough study of waveforms from a sequence of black hole configurations varying from previously treated head-on collisions to rep...
Stimulated emission and Hawking radiation in black hole analogues
Belgiorno, F
2016-01-01
Stimulated emission by black holes is discussed in light of the analogue gravity program. We first consider initial quantum states containing a definite number of particles, and then we take into account the case where the initial state is a coherent state. The latter case is particularly significant in the case where Hawking radiation is studied in dielectric black holes, and the emission is stimulated by a laser probe. We are particularly interested in the case of the electromagnetic field, for which stimulated radiation is calculated too.
W. X. Zhong
2014-09-01
In this paper, we use the canonical ensemble model to discuss the radiation of a Schwarzschild–de Sitter black hole on the black hole horizon. Using this model, we calculate the probability distribution from function of the emission shell. And the statistical meaning which compare with the distribution function is used to investigate the black hole tunnelling radiation spectrum.We also discuss the mechanism of information flowing from the black hole.
Radiation Regulation Bodies in South Africa
Tthere are two types Regulatory Bodies in South Africa: department of Health - Radiation Control (DoH) and National Nuclear Regulator (NNR). The function DoH include of Promotion and maintenance of health within the framework of National health plan, Protection against injury or disease caused by technological devises, Protection against injury or disease caused by radiation, Promote safe and legal use of such products. The National Nuclear Regulator authorizes Nuclear Installation License, Nuclear Vessel License, Certificate of Registration and Certificate of Exemption. Some of the Electronic Products include licensing electro-medical products, Import or manufactured License conditions, Radiation workers, Report forms, Use and Radio-nuclides. Nuclear Authorization is the process of granting, by the National Nuclear Regulator, a written approval to applicants or / and operating organizations to perform nuclear related activities as detailed in the scope of the authorization. International Trade Administration Commission of South Africa (ITAC) issue license for import and export of all products including electronic X-Ray products and Radio-nuclides
Hawking Radiation of a Charged Black Hole in Quantum Gravity
Oda, Ichiro
2015-01-01
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.
Quantum Tunneling Radiation of Kerr-NUT Black Hole
LI Hui-Ling; YANG Shu-Zheng; QI De-Jiang
2006-01-01
Based on particles in a dynamical geometry, extending the Parikh's method of quantum tunneling radiation,we deeply investigate the quantum tunneling radiation of Kerr-NUT black hole. When self-gravitating action, energyconservation, and angular momentum conservation are taken into account, the emission rate of the particle on the event horizon is related to the change of Bekenstein-Hawking entropy and the emission spectrum is not precisely thermal, but is consistent with an underlying unitary theory.
On Hawking Radiation of 3D Rotating Hairy Black Holes
Belhaj, A.; Chabab, M.; Moumni, H. EL; Masmar, K.; Sedra, M. B.
2015-01-01
We study the Hawking radiation of 3D rotating hairy black holes. More concretely, we compute the transition probability of a bosonic and fermionic particle in such backgrounds. Thew, we show that the transition probability is independent of the nature of the particle. It is observed that the charge of the scalar hair B and the rotation parameter a control such a probability.
Hawking radiation via tunnelling from general stationary axisymmetric black holes
Zhang Jing-Yi; Fan Jun-Hui
2007-01-01
Hawking radiation is viewed as a tunnelling process. In this way the emission rates of massless particles and massive particles tunnelling across the event horizon of general stationary axisymmetric black holes are calculated,separately. The emission spectra of these two different kinds of outgoing particles have the same functional form and both are consistent with an underlying unitary theory.
Hawking Radiation via Tunnelling from Arbitrarily Dimensional Schwarzschild Black Holes
REN Jun; ZHAO Zheng; GAO Chang-Jun
2005-01-01
@@ We extend Parikh's recent work to the arbitrarily dimensional Schwarzschild black holes whose Arnowitt-DeserMisner (ADM) mass is identical to its mass parameter. We view Hawking radiation as a tunnelling process across the event horizon. From the tunnelling probability we also find a leading correction to the semiclassical emission rate. The result consists with an underlying unitary theory.
Hawking radiation from AdS black holes
We investigate Hawking radiation from black holes in (d+1)-dimensional anti--de Sitter space. We focus on s waves, make use of the geometrical optics approximation, and follow three approaches to analyze the radiation. First, we compute a Bogoliubov transformation between Kruskal and asymptotic coordinates and compare the different vacua. Second, following a method due to Kraus, Parikh, and Wilczek, we view Hawking radiation as a tunneling process across the horizon and compute the tunneling probability. This approach uses an anti--de Sitter version of a metric originally introduced by Painleve for Schwarzschild black holes. From the tunneling probability one also finds a leading correction to the semiclassical emission rate arising from back reaction to the background geometry. Finally, we consider a spherically symmetric collapse geometry and the Bogoliubov transformation between the initial vacuum state and the vacuum of an asymptotic observer
Gravitational Radiation of Binaries Coalescence into Intermediate Mass Black Holes
李瑾; 仲元红; 潘宇
2012-01-01
This paper discusses the gravitation waveforms of binaries coalescence into intermediate mass black holes （about 30 times of the solar mass）. We focus on the non-spinning intermediate mass black hole located less than 100 Mpc from earth. By comparing two simulation waveforms （effective one body numerical relativity waveform （EOBNR）, phenomenological waveform）, we discuss the relationship between the effective distance and frequency; and through analyzing large amounts of data in event, we find that the phenomenological waveform is much smoother than EOBNR waveform, and has higher accuracy at the same effective distance.
Lymphocyte chromosome aberrations in partial-body fractionated radiation therapy
a relationship between lymphocyte chromosome aberration yields which occur in partial-body fractionated radiation therapy and those yields measured in vitro is derived. These calculations are applied to the case of patients undergoing radiation therapy for mammary carcinoma. (author)
Lymphocyte chromosome aberrations in partial-body fractionated radiation therapy
Ekstrand, K.E.; Dixon, R.L. (Wake Forest Univ., Winston-Salem, NC (USA))
1982-03-01
a relationship between lymphocyte chromosome aberration yields which occur in partial-body fractionated radiation therapy and those yields measured in vitro is derived. These calculations are applied to the case of patients undergoing radiation therapy for mammary carcinoma.
Dependence of the Black Body Force on Spacetime Geometry and Topology
Muniz, C R; Cunha, M S; Landim, R R; Filho, R N Costa
2015-01-01
In this manuscript we compute the corrections to the black body force due to spacetime geometry and topology. This recently discovered attractive force on neutral atoms is caused by the thermal radiation emitted from black bodies and here we investigate it in systems with spherical and cylindrical symmetries. For some astrophysical objects we find that the corrected force is greater than the flat case, showing that this kind of correction can be quite relevant when curved spaces are considered. Then we consider four cases: The Schwarzschild spacetime, the non-relativistic infinity cylinder, and both the static and stationary cosmic strings. For the spherically symmetric case we find that two corrections appear: One due to the gravitational modification of the temperature and the other due to the modification of the solid angle subtended by the atom. We apply the found results to a typical neutron star and to the Sun. For the cylindrical case, which is locally flat, no gravitational correction to the temperatu...
Hawking Radiation of Photons in a Vaidya-de Sitter Black Hole
Wu, S Q
2002-01-01
Hawking evaporation of photons in a Vaidya-de Sitter black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the time. It is shown that Hawking radiation of photons exists only for the complex Maxwell scalar $\\phi_0$ in the advanced Eddington-Finkelstein coordinate system. This asymmetry of Hawking radiation for different components of Maxwell fields probably arises from the asymmetry of spacetime in the advanced Eddington-Finkelstein coordinate system. It is shown that the black body radiant spectrum of photons resembles that of Klein-Gordon particles. PACS numbers: 04.70.Dy, 97.60.Lf
Energy Crisis in Astrophysics (Black Holes vs. N-Body Metrics)
Alley, C O; Mizobuchi, Y; Yilmaz, H; Alley, Carroll O; Leiter, Darryl L; Mizobuchi, Yutaka; Yilmaz, Huseyin
1999-01-01
The recent observation of the gamma ray burster GRB 990123, requiring at least two solar masses of energy in gamma radiation alone, created an energy crisis in astrophysics (Schilling 1999). We discuss a theorem which states that, of all four-dimensional curved spacetime theories of gravity viable with respect to the four classical weak field tests, only one unique case, the Yilmaz theory, has interactive N-body (multiparticle) solutions and this unique case has no event horizons. The theorem provides strong theoretical support for Robertson's explanation of the large energy output of the gamma ray burster GRB 990123 (Robertson 1999b). This explanation requires a switch from black holes (a 1-body solution with horizon) to the case of horizon-free interactive N-body solutions. In addition to the good news that the long sought N-body solutions are found, this unique case enjoys further strong support from other areas of gravitational physics. This development does not rule out GRB models with beaming, which can...
Stereotactic Body Radiation Therapy in Spinal Metastases
Ahmed, Kamran A. [Mayo Medical School, College of Medicine, Mayo Clinic, Rochester, MN (United States); Stauder, Michael C.; Miller, Robert C.; Bauer, Heather J. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Rose, Peter S. [Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN (United States); Olivier, Kenneth R. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Brown, Paul D. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Brinkmann, Debra H. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Laack, Nadia N., E-mail: laack.nadia@mayo.edu [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States)
2012-04-01
Purpose: Based on reports of safety and efficacy, stereotactic body radiotherapy (SBRT) for treatment of malignant spinal tumors was initiated at our institution. We report prospective results of this population at Mayo Clinic. Materials and Methods: Between April 2008 and December 2010, 85 lesions in 66 patients were treated with SBRT for spinal metastases. Twenty-two lesions (25.8%) were treated for recurrence after prior radiotherapy (RT). The mean age of patients was 56.8 {+-} 13.4 years. Patients were treated to a median dose of 24 Gy (range, 10-40 Gy) in a median of three fractions (range, 1-5). Radiation was delivered with intensity-modulated radiotherapy (IMRT) and prescribed to cover 80% of the planning target volume (PTV) with organs at risk such as the spinal cord taking priority over PTV coverage. Results: Tumor sites included 48, 22, 12, and 3 in the thoracic, lumbar, cervical, and sacral spine, respectively. The mean actuarial survival at 12 months was 52.2%. A total of 7 patients had both local and marginal failure, 1 patient experienced marginal but not local failure, and 1 patient had local failure only. Actuarial local control at 1 year was 83.3% and 91.2% in patients with and without prior RT. The median dose delivered to patients who experienced local/marginal failure was 24 Gy (range, 18-30 Gy) in a median of three fractions (range, 1-5). No cases of Grade 4 toxicity were reported. In 1 of 2 patients experiencing Grade 3 toxicity, SBRT was given after previous radiation. Conclusion: The results indicate SBRT to be an effective measure to achieve local control in spinal metastases. Toxicity of treatment was rare, including those previously irradiated. Our results appear comparable to previous reports analyzing spine SBRT. Further research is needed to determine optimum dose and fractionation to further improve local control and prevent toxicity.
Radiative Shocks in Rotating Accretion Flows around Black Holes
Okuda, T; Toscano, E; Molteni, D
2004-01-01
It is well known that the rotating accretion flows around black holes form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually stopped by the centrifugal force. We examine numerically such shock waves in 1D and 2D accretion flows, taking account of the cooling and heating of gas and the radiation transport. The numerical results show that the shock location shifts outward compared with that in the adiabatic solutions and that the more rarefied ambient density leads to the more outward shock position. In the 2D-flow, we find an intermediate frequency QPO behavior of the shock location as is observed in the black hole candidate GRS 1915+105.
A Model For The Absorption Of Thermal Radiation By Gold-Black
Quinlan, Brendan Robert
2015-01-01
The work presented here addresses an important topic in thermal radiation detection when gold-black is used as an absorber. Sought is a model to simulate the absorption of thermal radiation by gold-black. Fractal geometry is created to simulate the topology of gold-black. Then electrical circuits based on the topology are identified that capture the physics of the interaction between the gold-black material and incident electro-magnetic radiation. Parameters of the model are then adj...
Rynal Devanathan
2013-01-01
Full Text Available Background: Excess weight contributes to the development and progression of Type 2 diabetes mellitus (T2DM. Distorted body image amongst urban Black women and the perception that thinness is linked with HIV, may however be compounding the problem, particularly in areas with a high HIV burden.Objectives: This study aimed to compare the perception of body image in urban Black women with and without T2DM.Methods: A cross-sectional comparative study was conducted on 328 Black women systematically sampled into two groups (with and without T2DM. Body mass index (BMI (weight [kg]/height[m2] was determined and the adapted Stunkard Body Image Silhouettes for Black women was used to determine perceived body image (PBI.Results: Seventy-two per cent had T2DM and in this group 89% were obese, with a mean BMI of 39.5 kg/m2 (s.d. ± 8.5. In the non-diabetes group (NDG 44% were obese, with a mean BMIof 31.3 kg/m2 (s.d. ± 9.0 Black women underestimated their body image across all weight categories (p < 0.05. Both groups (99% of the study group also perceived thinness as being associated with HIV.Conclusions: This study identified an incongruence between PBI and actual BMI amongst urban Black women. This, combined with their belief that thinness is associated with HIV, places those with T2DM at risk of secondary complications arising from diabetes mellitus, and those without diabetes mellitus at a higher risk of developing T2DM. A discrepancy between PBI and BMI may therefore serve as a risk marker to alert clinicians to use a more ethno-cultural specific approach in engaging with urban Black women regarding weight loss strategies in the future.
General Relativistic Radiative Transfer: Applications to Black-Hole Systems
Wu, Kinwah; Fuerst, Steven V.; Mizuno, Yosuke; Nishikawa, Ken-Ichi; Branduardi-Raymont, Graziella; Lee, Khee-Gan
2007-01-01
We present general relativistic radiation transfer formulations which include opacity effects due to absorption, emission and scattering explicitly. We consider a moment expansions for the transfer in the presence of scattering. The formulation is applied to calculation emissions from accretion and outflows in black-hole systems. Cases with thin accretion disks and accretion tori are considered. Effects, such as emission anisotropy, non-stationary flows and geometrical self-occultation are investigated. Polarisation transfer in curved space-time is discussed qualitatively.
Hawking Radiation as Quantum Tunneling from Noncommutative Schwarzschild Black Hole
Nozari, Kourosh; Mehdipour, S. Hamid
2008-01-01
We study tunneling process through quantum horizon of a Schwarzschild black hole in noncommutative spacetime. This is done by considering the effect of smearing of the particle mass as a Gaussian profile in flat spacetime. We show that even in this noncommutative setup there will be no correlation between the different modes of radiation which reflects the fact that information doesn't come out continuously during the evaporation process at least at late-time. However, due to spacetime noncom...
Ruling out stray thermal radiation in analogue black holes
Doukas, Jason; Adesso, Gerardo; Fuentes, Ivette
2014-01-01
Experimental searches for the thermal radiation from analogue black holes require the measurement of very low temperatures in regimes where other thermal noises may interfere or even mimic the sought-after effect. In this letter, we parameterize the family of bosonic thermal channels which give rise to such thermal effects and show that by use of coherent states and homodyne detection one can rule out the non-Hawking contributions and identify those candidate sources which arise from Hawking-...
Radiatively Driven Winds from Effective Boundary Layer around Black Holes
Indranil Chattopadhyay; Sandip K. Chakrabarti
2002-03-01
Matter accreting onto black holes suffers a standing or oscillating shock wave in much of the parameter space. The post-shock region is hot, puffed up and reprocesses soft photons from a Keplerian disc to produce the characteristic hard tail of the spectrum of accretion discs. The post-shock torus is also the base of the bipolar jets. We study the interaction of these jets with the hard photons emitted from the disc. We show that radiative force can accelerate outflows but the drag can limit the terminal speed. We introduce an equilibrium speed eq as a function of distance, above which the flow will experience radiative deceleration.
Dirac Particles' Hawking Radiation from a Schwarzschild Black Hole
HE Xiao-Kai; LIU Wen-Biao
2007-01-01
@@ Considering energy conservation and the backreaction of particles to spacetime, we investigate the massless/massive Dirac particles' Hawking radiation from a Schwarzschild black hole. The exact expression of the emission rate near the horizon is obtained and the result indicates that Hawking radiation spectrum is not purely thermal. The result obtained is consistent with the results obtained before. It satisfies the underlying unitary theory and offers a possible mechanism to explain the information loss paradox. Whereas the improved Damour-Ruffini method is more concise and understandable.
Hydrodynamic and hydromagnetic stability of black holes with radiative transfer
Roger Blandford; Jonathan C Mckinney; Nadia Zakamska
2011-07-01
Subrahmanyan Chandrasekhar (Chandra) was just eight years old when the ﬁrst astrophysical jet was discovered in M87. Since then, jets have been uncovered with a wide variety of sources including accretion disks orbiting stellar and massive black holes, neutron stars, isolated pulsars, -ray bursts, protostars and planetary nebulae. This talk will be primarily concerned with collimated hydromagnetic outﬂows associated with spinning, massive black holes in active galactic nuclei. Jets exhibit physical processes central to three of the major research themes in Chandrasekhar’s research career – radiative transfer, magnetohydrodynamics and black holes. Relativistic jets can be thought of as `exhausts’ from both the hole and its orbiting accretion disk, carrying away the energy liberated by the rotating spacetime and the accreting gas that is not radiated. However, no aspect of jet formation, propagation and radiation can be regarded as understood in detail. The combination of new -ray, radio and optical observations together with impressive advances in numerical simulation make this a good time to settle some long-standing debates.
Ethnic Identity and Body Image among Black and White College Females
Baugh, Eboni; Mullis, Ron; Mullis, Ann; Hicks, Mary; Peterson, Gary
2010-01-01
Objective: This study examines ethnic identity and body image in black and white college females. Participants: Researchers surveyed 118 students at 2 universities, 1 traditionally white and 1 historically black. Methods: Correlations and multivariate analysis of variance (MANOVA) were used to investigate the relationship between race, ethnic…
Jung, Jaehee; Forbes, Gordon B.
2013-01-01
Multiple measures of body dissatisfaction and behaviors associated with disordered eating were studied in 258 White girls, 223 White boys, 106 Black girls, and 82 Black boys. All participants were unpaid volunteers between the ages of 12 and 15 attending six middle schools in Delaware and Maryland. On two self-ideal figure drawing discrepancy…
Sri Rachma, Aprilita Bugiwati
2008-01-01
This experiment was done at 292 head of Japanese black bull at Kagoshima and Miyazaki Prefectural Experimental Stations Japan to find out the relationship between ultrasonic estimates of carcass traits and body measurements as one of criteria to select Japanese black bull. The carcass traits of 20 months of age were predicted using the ultrasonic machine. The body dimensions were measured at the end of performance test (12 months of age) and 16 months of age. The ultrasonic evaluati...
Spin-multipole effects in binary black holes and the test-body limit
Vines, Justin
2016-01-01
We discuss the Hamiltonian for the conservative dynamics of generic-orbit arbitrary-mass-ratio spinning binary black holes, at the leading post-Newtonian orders at each order in an expansion in spins, to all orders in the spins. The leading-order couplings can all be obtained from a map to the motion of a test black hole (a test body with the spin-induced multipoles of a Kerr black hole) in the Kerr spacetime, as is confirmed with direct post-Newtonian calculations for arbitrary mass ratios. Furthermore, all of the couplings can be "deduced" from those of a pole-dipole test body in Kerr.
Accretion of radiation and rotating primordial black holes
Mahapatra, S.; Nayak, B.
2016-02-01
We consider rotating primordial black holes (PBHs) and study the effect of accretion of radiation in the radiation-dominated era. The central part of our analysis deals with the role of the angular momentum parameter on the evolution of PBHs. We find that both the accretion and evaporation rates decrease with an increase in the angular momentum parameter, but the rate of evaporation decreases more rapidly than the rate of accretion. This shows that the evaporation time of PBHs is prolonged with an increase in the angular momentum parameter. We also note that the lifetime of rotating PBHs increases with an increase in the accretion efficiency of radiation as in the case of nonrotating PBHs.
Oscillations of radiation pressure supported tori near black holes
Mazur, Grzegorz P; Sądowski, Aleksander; Mishra, Bhupendra; Kluźniak, Włodek
2015-01-01
We study the dynamics of radiation pressure supported tori around Schwarzschild black holes, focusing on their oscillatory response to an external perturbation. Using KORAL, a general relativistic radiation hydrodynamics code capable of modeling all radiative regimes from the optically thick to the optically thin, we monitor a sample of models at different initial temperatures and opacities, evolving them in two spatial dimensions for $\\sim 165$ orbital periods. The dynamics of models with high opacity is very similar to that of purely hydrodynamics models, and it is characterized by regular oscillations which are visible also in the light curves. As the opacity is decreased, the tori quickly and violently migrate towards the gas-pressure dominated regime, collapsing towards the equatorial plane. When the spectra of the $L_2$ norm of the mass density are considered, high frequency inertial-acoustic modes of oscillations are detected (with the fundamental mode at a frequency $68 M_{\\rm BH}^{-1}\\,\\rm Hz$), in c...
Effects of gamma radiation on sensorial properties in black tea
The black tea (Camellia sinensis) is the most consumed beverage in the world and its consumption has increased, manly in occidental countries, due to the fact that this drink has large antioxidants quantities. In this type of tea, the taste determines the product qualities and its final value. Several studies reported that food irradiation is an excellent process to disinfect food, reducing storage losses and extended its shelf life. This treatment can inhibit cellular division, promoting a molecular and DNA structural modification. Depending on the dose applied, the irradiation can modify sensorial properties, influencing the marked cost. The sensorial analysis is one of the main tests to detect any better or worse changes, by consumers. The aim of this study is to evaluate the effect of ionizing radiation on sensorial properties in black tea. Samples will be irradiated with a 60Co source, at doses of 0, 5, and 10 kGy. (author)
On the origin of black hole evaporation radiation
The physical basis underlying the black hole evaporation process is clarified by a calculation of the expectation value of the energy-momentum tensor for a massless scalar field in a completely general two dimensional collapse scenario. It is found that radiation is produced inside the collapsing matter which propagates both inwards and outwards. The ingoing component eventually emerges from the star after travelling through the centre. The outgoing energy flux appears at infinity as the evaporation radiation discovered by Hawking (Comm. Math. Phys.; 43: 199 (1975)). At late times, outside the star, the former component fades out exponentially, and the latter component approaches a value which is independent of the details of the collapse process. In the special case of a collapsing hollow, thin shell of matter, all the radiation is produced at the shell. These results are independent of regularization ambiguities, which enter only the static vacuum polarization terms in the energy-momentum tensor. The significance of an earlier remark about black hole explosions is discussed in the light of these results. (author)
Spherically Symmetric Static Solution for a Schwarzschild Black Hole with Its Hawking Radiation
HUANG Chao-Guang
2000-01-01
A black hole and its Hawking radiation may be in stable thermal equilibrium. In this letter, the static spherically symmetric numerical solution for a Schwarzschild black hole with its Hawking radiation are obtained. In the calculation, the equilibrium system is supposed to consist of a black hole, thermal radiation and a two-dimensional surface layer. The solutions obtained are compared with the York's back-reaction approach and the Zhao-Liu thermodynamic approach.
Saleh, Mahamat; Thomas, Bouetou Bouetou; Crepin, Kofane Timoleon
2016-01-01
We investigate quasinormal modes (QNMs) and Hawking radiation of a Reissner-Nordstr\\"om black hole sur-rounded by quintessence. The Wentzel-Kramers-Brillouin (WKB) method is used to evaluate the QNMs and the rate of radiation. The results show that due to the interaction of the quintessence with the background metric, the QNMs of the black hole damp more slowly when increasing the density of quintessence and the black hole radiates at slower rate.
Mergers of Non-spinning Black-hole Binaries: Gravitational Radiation Characteristics
Baker, John G.; Boggs, William D.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; vanMeter, James R.
2008-01-01
We present a detailed descriptive analysis of the gravitational radiation from black-hole binary mergers of non-spinning black holes, based on numerical simulations of systems varying from equal-mass to a 6:1 mass ratio. Our primary goal is to present relatively complete information about the waveforms, including all the leading multipolar components, to interested researchers. In our analysis, we pursue the simplest physical description of the dominant features in the radiation, providing an interpretation of the waveforms in terms of an implicit rotating source. This interpretation applies uniformly to the full wavetrain, from inspiral through ringdown. We emphasize strong relationships among the l = m modes that persist through the full wavetrain. Exploring the structure of the waveforms in more detail, we conduct detailed analytic fitting of the late-time frequency evolution, identifying a key quantitative feature shared by the l = m modes among all mass-ratios. We identify relationships, with a simple interpretation in terms of the implicit rotating source, among the evolution of frequency and amplitude, which hold for the late-time radiation. These detailed relationships provide sufficient information about the late-time radiation to yield a predictive model for the late-time waveforms, an alternative to the common practice of modeling by a sum of quasinormal mode overtones. We demonstrate an application of this in a new effective-one-body-based analytic waveform model.
Decontamination of black pepper and red pepper by gamma radiation
In the present work, it has been studied the decontamination of two types of spices (black pepper and red pepper) by gamma radiation. The initial microbial population of spices not treated is about 10 (7) to 10 (8) per gram. The population decrease exponentially with irradiation dose. By this, it has been established that a dose of 6 kGy reduces the microbial flora low than 10 (3) per gram. A total elimination of moulds is obtained at dose of 8 kGy
Who's that Girl: Television's Role in the Body Image Development of Young White and Black Women
Schooler, Deborah; Ward, L. Monique; Merriwether, Ann; Caruthers, Allison
2004-01-01
Although findings indicate a connection between frequent media use and greater body dissatisfaction, little attention has focused on the role of race. Accordingly, this study investigates the relation between television viewing and body image among 87 Black and 584 White women. Participants reported monthly viewing amounts of mainstream and…
High energy radiation effects on the human body
High-energy radiation injuries and their risks were recognized, information on low-energy radiation injuries was also arranged, and with these backgrounds, countermeasures against prevention of radiation injuries were considered. Redintegration of DNA and mutation by radiation were described, and relationship between radiation injuries and dose was considered. Interaction of high-energy radiation and substances in the living body and injuries by the interaction were also considered. Expression method of risk was considered, and a concept of protection dose was suggested. Protection dose is dose equivalent which is worthy of value at the point where the ratio to permissible dose distributed among each part of the body is at its maximum in the distribution of dose equivalent formed within the body when standard human body is placed at a certain radiation field for a certain time. Significance and countermeasures of health examination which is under an abligation to make radiation workers receive health check were thought, and problems were proposed on compensation when radiation injuries should appear actually. (Tsunoda, M.)
Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty
Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kinne, S.; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.
2013-01-01
The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.
Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty
Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Bian, Huisheng; Bellouin, N.; Diehl, T.; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kinne, Stefan; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, Xiaohong; Penner, Joyce E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, Kai
2013-03-01
The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.
Radiation between segments of the seated human body
Sørensen, Dan Nørtoft
2002-01-01
Detailed radiation properties for a thermal manikin were predicted numerically. The view factors between individual body-segments and between the body-segments and the outer surfaces were tabulated. On an integral basis, the findings compared well to other studies and the results showed that situ...
Oscillations of radiation pressure supported tori near black holes
Mazur, Grzegorz P.; Zanotti, Olindo; Sądowski, Aleksander; Mishra, Bhupendra; Kluźniak, Wlodek
2016-03-01
We study the dynamics of radiation pressure supported tori around Schwarzschild black holes, focusing on their oscillatory response to an external perturbation. Using KORAL, a general relativistic radiation-hydrodynamics code capable of modelling all radiative regimes from the optically thick to the optically thin, we monitor a sample of models at different initial temperatures and opacities, evolving them in two spatial dimensions for ˜165 orbital periods. The dynamics of models with high opacity is very similar to that of purely hydrodynamics models, and it is characterized by regular oscillations which are visible also in the light curves. As the opacity is decreased, the tori quickly and violently migrate towards the gas-pressure dominated regime, collapsing towards the equatorial plane. When the spectra of the L2 norm of the mass density are considered, high-frequency inertial-acoustic modes of oscillations are detected (with the fundamental mode at a frequency 68 M_BH^{-1} Hz), in close analogy to the phenomenology of purely hydrodynamic models. An additional mode of oscillation, at a frequency 129 M_BH^{-1} Hz, is also found, which can be unambiguously attributed to the radiation. The spectra extracted from the light curves are typically noisier, indicating that in a real observation such modes may not be easily detected.
Spin-multipole effects in binary black holes and the test-body limit
Vines, Justin; Steinhoff, Jan
2016-01-01
We discuss the Hamiltonian for the conservative dynamics of generic-orbit arbitrary-mass-ratio spinning binary black holes, at the leading post-Newtonian orders at each order in an expansion in spins, to all orders in the spins. The leading-order couplings can all be obtained from a map to the motion of a test black hole (a test body with the spin-induced multipoles of a Kerr black hole) in the Kerr spacetime, as is confirmed with direct post-Newtonian calculations for arbitrary mass ratios. ...
Characteristics of Quantum Radiation of Slowly Varying Nonstationary Kerr-Newman Black Holes
Hua, Jia-Chen; Huang, Yong-chang
2006-01-01
Quantum radiative characteristics of slowly varying nonstationary Kerr-Newman black holes are investigated by using the method of generalized tortoise coordinate transformation. It is shown that the temperature and the shape of the event horizon of this kind of black holes depend on the time and the angle. Further, we reveal a relationship that is ignored before between thermal radiation and non-thermal radiation, which is that the chemical potential in thermal radiation spectrum is equal to ...
Hawking radiation of massive vector particles from the linear dilaton black holes
Li, Ran; Zhao, Junkun
2016-07-01
By using the tunneling formalism, we calculated the massive vector particles' Hawking radiation from the non-rotating and rotating linear dilaton black holes. By applying the WKB approximation to the Proca field equation that govern the dynamics of massive vector bosons, we derive the tunneling probabilities and radiation spectrums of the emitted vector particles from the linear dilaton black holes. The Hawking temperatures of the linear dilaton black holes have been recovered, which are consistent with the previous results in the literature. This means that the vector particles' tunneling method can also be used in studying the Hawking radiation of asymptotically non-flat and non-AdS black holes.
Some hazardous effects of radiations on human body
The radiation hazards and its dangers has been increasing by leaps and bounds. Certain elements and particles are capable of degrading by themselves and releasing energy in the form of radiations. Such types of radiations can not be seen by naked eyes, but are capable of penetrating our body and can produce serious ill effects. Acute radiation syndrome can be divided into three main categories: (1) Hematopoietic:- In this type of syndrome there is fall in blood cells, causes infections, bleeding and anemia (2) Gastrointestinal:- It occurs at the exposures of 600-1000 rad. Nausea, loss of appetite, vomiting and abdominal pain are main symptoms. (3) Neurovascular:- When exposure greater than 1000 rad occurs it effects nervous system which results in dizziness, headache or decreased level of consciousness. The various organs or parts of body are affected by exposure to radiations such as the losing of hair and clumping of hairs with radiation exposure above 200 rems or higher, same way the thyroid gland is susceptible to radioactive iodine, in sufficient amount iodine can destroy some parts or fully the thyroid. When a person is exposed to radiations around 100 rems the blood lymphocyte cell count will be reduced, leaving the victim more susceptible to infection. If the exposure is between 1000-5000 rems blood vessels got damage resulting into heart failure, in short, we can say that in order to prevent body from radiation the only way to keep away from them. (author)
Hawking Radiation of Vector Particles via Tunneling From 4-Dimensional And 5-Dimensional Black Holes
Feng, Zhongwen; Zu, Xiaotao
2016-01-01
Using Proca equation and WKB approximation, we investigate Hawking radiation of vector particles via tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole. The results show that the tunneling rates and Hawking temperatures are depended on the properties of spacetime (event horizon, mass and angular momentum). Besides, our results are the same as scalars and fermions tunneling from 4-dimensional Kerr-de Sitter black hole and 5-dimensional Schwarzschild-Tangherlini black hole.
NON-THERMAL RADIATION FROM A NON-KERR-NEWMAN BLACK HOLE
谢实崇; 杨雪特; 杨树政; 林理彬
2001-01-01
In the spacetime of a charged spinning black hole, the distribution of particle energy levels has been studied. Near the event horizon of such a black hole a crossing of the particle energy levels exists, which leads to the occurrence of non-thermal radiation of the black hole. This quantum effect is non-thermal and also different from those of the Kerr and Kerr-Newman black holes.
Horizons of radiating black holes in Einstein-Gauss-Bonnet gravity
A Vaidya-based model of a radiating black hole is studied in a 5-dimensional Einstein gravity with Gauss-Bonnet contribution of quadratic curvature terms. The structure and locations of the apparent and event horizons of the radiating black hole are determined
Studies on radiation induced radicals in irradiated black pepper after long-term storage
Using ESR the radiation induced radicals of black pepper after long-term storage were studied. Upon gamma ray irradiation, new signals were detected as twin peaks. It was revealed that these signals were very stable after the six month storage. We concluded that radiation induced new signals are very useful to know that the black pepper was irradiated or not. (author)
Information-carrying Hawking radiation and the number of microstate for a black hole
Qing-yu Cai; Chang-pu Sun; Li You
2016-01-01
We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein–Hawking entropies for Schwarzschild black holes and Reissner–Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner–Nordström black hole, its number of microstate and the...
Radiation from collapsing shells, semiclassical backreaction, and black hole formation
We provide a detailed analysis of quantum field theory around a collapsing shell and discuss several conceptual issues related to the emission of radiation flux and formation of black holes. Explicit calculations are performed using a model for a collapsing shell, which turns out to be analytically solvable. We use the insights gained in this model to draw reliable conclusions regarding more realistic models. We first show that any shell of mass M, which collapses to a radius close to r=2M, will emit approximately thermal radiation for a period of time. In particular, a shell that collapses from some initial radius to a final radius 2M(1-ε2)-1 (where ε2). Later on (t>>Mln(1/ε2)), the flux from such a shell will decay to zero exponentially. We next study the effect of backreaction computed using the vacuum expectation value of the stress tensor on the collapse. We find that, in any realistic collapse scenario, the backreaction effects do not prevent the formation of the event horizon. The time at which the event horizon is formed is, of course, delayed due to the radiated flux--which decreases the mass of the shell--but this effect is not sufficient to prevent horizon formation. We also clarify several conceptual issues and provide pedagogical details of the calculations in the Appendices to the paper.
Black Pete, "smug ignorance," and the value of the black body in postcolonial Netherlands
Van Der Pijl, Yvon; Goulordava, Karina
2014-01-01
This article discusses the controversies over the blackface figure Black Pete (Zwarte Piet)-central to the popular Dutch Saint Nicholas holiday tradition-and the public uproar surrounding the Saint Nicholas feast in 2013. It combines history, social theory, and patchwork ethnography, and draws on th
(Radiation carcinogenesis in the whole body system)
Fry, R.J.M.
1990-12-14
The objectives of the trip were: to take part in and to give the summary of a Symposium on Radiation Carcinogenesis at Tokyo, and to give a talk at the National Institute of Radiological Sciences at Chiba. The breadth of the aspects considered at the conference was about as broad as is possible, from effects at the molecular level to human epidemiology, from the effects of tritium to cancer induction by heavy ions. The events induced by cancer that lead to cancer and the events that are secondary are beginning to come into better focus but much is still not known. Interest in suppressor genes is increasing rapidly in the studies of human tumors and many would predict that the three or four suppressor genes associated with cancer are only the first sighting of a much larger number.
Cuesta-Martínez, Carlos F; Mimica, Petar
2014-01-01
We extend an existing theoretical model to explain the class of Black-Body Dominated GRBs, namely long lasting events characterized by the presence of a notable thermal component trailing the GRB prompt emission, and a rather weak traditional afterglow. GRB 101225A, the Christmas Burst (CB), is a prototype of such class. It has been suggested that BBD-GRBs could result from the merger of a binary system formed by a neutron star and the Helium core of a main sequence star. We have modeled the propagation of ultrarelativistic jets through the environment left behind the merger by means of detailed relativistic hydrodynamic numerical simulations. In this paper, the output of our numerical models is further postprocessed to obtain the (thermal) radiative signature of the resulting outflow. The complete (thermal and non-thermal) output of our models is considered in a companion contribution. Here, we outline the most relevant dynamical details of the jet propagation and connect them to the generation of thermal ra...
Hawking radiation from a spherical loop quantum gravity black hole
Gambini, Rodolfo
2013-01-01
We introduce quantum field theory on quantum space-times techniques to characterize the quantum vacua as a first step towards studying black hole evaporation in spherical symmetry in loop quantum gravity and compute the Hawking radiation. We use as quantum space time the recently introduced exact solution of the quantum Einstein equations in vacuum with spherical symmetry and consider a spherically symmetric test scalar field propagating on it. The use of loop quantum gravity techniques in the background space-time naturally regularizes the matter content, solving one of the main obstacles to back reaction calculations in more traditional treatments. The discreteness of area leads to modifications of the quantum vacua, eliminating the trans-Planckian modes close to the horizon, which in turn eliminates all singularities from physical quantities, like the expectation value of the stress energy tensor. Apart from this, the Boulware, Hartle--Hawking and Unruh vacua differ little from the treatment on a classical...
Image-Guidance for Stereotactic Body Radiation Therapy
The term stereotactic body radiation therapy (SBRT) describes a recently introduced external beam radiation paradigm by which small lesions outside the brain are treated under stereotactic conditions, in a single or few fractions of high-dose radiation delivery. Similar to the treatment planning and delivery process for cranial radiosurgery, the emphasis is on sparing of adjacent normal tissues through the creation of steep dose gradients. Thus, advanced methods for assuring an accurate relationship between the target volume position and radiation beam geometry, immediately prior to radiation delivery, must be implemented. Such methods can employ imaging techniques such as planar (e.g., x-ray) or volumetric (e.g., computed tomography [CT]) approaches and are commonly summarized under the general term image-guided radiation therapy (IGRT). This review summarizes clinical experience with volumetric and ultrasound based image-guidance for SBRT. Additionally, challenges and potential limitations of pre-treatment image-guidance are presented and discussed
Taste aversions conditioned with partial body radiation exposures
Radiation-induced taste aversion was compared in rats which received partial body exposure to the head or abdomen with rats receiving whole body irradiation. Exposure levels ranged from 25 to 300 roentgens (R). In additional groups, saccharin aversion to partial body gamma ray exposures of the abdomen were conditioned in animals which had prior experience with the saccharin solution. Aversion was measured with a single-bottle short-term test, a 23-hour preference test and by the number of days taken to recover from the aversion. Whole-body exposure was most effective in conditioning the aversion, and exposure of the abdominal area was more effective than exposure to the head. Also, the higher the exposure, the stronger the aversion. Rats receiving prior experience with the saccharin did not condition as well as control rats with no prior saccharin experience. The possible role of radiation-induced taste aversion in human radiotherapy patients was discussed. (author)
Scattering coefficients and gray-body factor for 1D BEC acoustic black holes: Exact results
Fabbri, Alessandro; Balbinot, Roberto; Anderson, Paul R.
2016-03-01
A complete set of exact analytic solutions to the mode equation is found in the region exterior to the acoustic horizon for a class of 1D Bose-Einstein condensate acoustic black holes. From these, analytic expressions for the scattering coefficients and gray-body factor are obtained. The results are used to verify previous predictions regarding the behaviors of the scattering coefficients and gray-body factor in the low-frequency limit.
Scattering coefficients and gray-body factor for 1D BEC acoustic black holes: exact results
Fabbri, Alessandro; Anderson, Paul R
2015-01-01
A complete set of exact analytic solutions to the mode equation are found in the region exterior to the acoustic horizon for a class of 1D Bose-Einstein condensate (BEC) acoustic black holes. From these, analytic expressions for the scattering coefficients and gray-body factor are obtained. The results are used to verify previous predictions regarding the behaviors of the scattering coefficients and gray-body factor in the low frequency limit.
Accurate Waveforms for Non-spinning Binary Black Holes using the Effective-one-body Approach
Buonanno, Alessandra; Pan, Yi; Baker, John G.; Centrella, Joan; Kelly, Bernard J.; McWilliams, Sean T.; vanMeter, James R.
2007-01-01
Using numerical relativity as guidance and the natural flexibility of the effective-one-body (EOB) model, we extend the latter so that it can successfully match the numerical relativity waveforms of non-spinning binary black holes during the last stages of inspiral, merger and ringdown. Here, by successfully, we mean with phase differences black-hole masses. The final black-hole mass and spin predicted by the numerical simulations are used to determine the ringdown frequency and decay time of three quasi-normal-mode damped sinusoids that are attached to the EOB inspiral-(plunge) waveform at the light-ring. The accurate EOB waveforms may be employed for coherent searches of gravitational waves emitted by non-spinning coalescing binary black holes with ground-based laser-interferometer detectors.
The Mirror of Television: A Comparison of Black and White Adolescents' Body Image.
Botta, Renee A.
2000-01-01
Finds that black adolescent girls were more satisfied with their bodies and had a larger personal ideal size than white adolescent girls, but engaged in no fewer eating-disordered behaviors and had no less drive to be thin; and these girls idealized television images equally and were as likely to compare themselves and their friends to television…
Are Black-White Differences in Females' Body Dissatisfaction Decreasing? A Meta-Analytic Review
Roberts, Alan; Cash, Thomas F.; Feingold, Alan; Johnson, Blair T.
2006-01-01
Proponents of the sociocultural model of eating disorders have suggested that ethnic differences in body dissatisfaction may be diminishing as the thin ideal of beauty becomes more widely disseminated among minority women. In a meta-analysis, the authors examined temporal trends in Black-White differences and also examined whether these…
Hamilton-Jacobi Ansatz to Study the Hawking Radiation of Kerr-Newman Black Holes
Chen, Deyou; Yang, Shuzheng
Taking the self-gravitation interaction and unfixed background space-time into account, we study the Hawking radiation of Kerr-Newman-Kasuya black holes using Hamilton-Jacobi method. The result shows that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the radiation spectrum deviates from the purely thermal one, which is accordant with that obtained using Parikh and Wilczek's method and gives a correction to the Hawking radiation of the black hole.
Corrected Hawking Radiation of Dirac Particles from a General Static Riemann Black Hole
Ge-Rui Chen
2013-01-01
Full Text Available Considering energy conservation and the back reaction of radiating particles to the spacetime, we investigate the massive Dirac particles' Hawking radiation from a general static Riemann black hole using improved Damour-Ruffini method. A direct consequence is that the radiation spectrum is not strictly thermal. The correction to the thermal spectrum is consistent with an underlying unitary quantum theory and this may have profound implications for the black hole information loss paradox.
Quantum radiation of non-stationary Kerr-Newman-de Sitter black hole
Jiang Qing-Quan; Yang Shu-Zheng; Li Hui-Ling
2005-01-01
By introducing a new tortoise coordinate transformation, we investigate the quantum thermal and non-thermal radiations of a non-stationary Kerr-Newman-de Sitter black hole. The accurate location and radiate temperature of the event horizon as well as the maximum energy of the non-thermal radiation are derived. It is shown that the radiate temperature and the maximum energy are related to not only the evaporation rate, but also the shape of the event horizon, moreover the maximum energy depends on the electromagnetic potential. Finally, we use the results to reduce the non-stationary Kerr-Newman black hole, the non-stationary Kerr black hole, the stationary Kerr-Newman-de Sitter black hole, and the static Schwarzshild black hole.
Hawking radiation from a spherical loop quantum gravity black hole
We introduce quantum field theory on quantum space-times techniques to characterize the quantum vacua as a first step toward studying black hole evaporation in spherical symmetry in loop quantum gravity and compute the Hawking radiation. We use as quantum space-time the recently introduced exact solution of the quantum Einstein equations in vacuum with spherical symmetry and consider a spherically symmetric test scalar field propagating on it. The use of loop quantum gravity techniques in the background space-time naturally regularizes the matter content, solving one of the main obstacles to back-reaction calculations in more traditional treatments. The discreteness of area leads to modifications of the quantum vacua, eliminating the trans-Planckian modes close to the horizon, which in turn eliminates all singularities from physical quantities, like the expectation value of the stress–energy tensor. Apart from this, the Boulware, Hartle–Hawking and Unruh vacua differ little from the treatment on a classical space-time. The asymptotic modes near scri are reproduced very well. We show that the Hawking radiation can be computed, leading to an expression similar to the conventional one but with a high frequency cutoff. Since many of the conclusions concern asymptotic behavior, where the spherical mode of the field behaves in a similar way as higher multipole modes do, the results can be readily generalized to non spherically symmetric fields. (paper)
She Had a Name That God Didn’t Give Her: Thinking the Body through Atheistic Black Radical Feminism
Marquis Bey
2015-01-01
The article attempts to demonstrate the necessity of acknowledging the body when considering the current Black Lives Matter movement, give an account of Black female and trans erasure, and ultimately (re)affirm the lived embodiment of Black, female, and trans bodies, all through an atheistic lens. Atheism here, while indeed denying the existence of gods, has as its primary concern affirming life. Too often is theology, as theologian Anthony Pinn says, “a theology of no-body”; thus atheistic f...
Information-carrying Hawking radiation and the number of microstate for a black hole
Cai, Qing-yu; You, Li
2016-01-01
We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein-Hawking entropies for Schwarzschild black holes and Reissner-Nordstr\\"om black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner-Nordstr\\"om black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein-Hawking entropy of extremal black holes in the semiclassical limit.
Hawking radiation from z=3 and z=1-Lifshitz black holes
Lepe, Samuel
2014-01-01
The Hawking radiation considered as a tunneling process, by using a Hamilton-Jacobi prescription, is discussed for both z=3 and z=1-Lifshitz black holes. We have found that the tunneling rate (which is not thermal but related to the change of entropy) for the z=3-Lifshitz black hole (which does not satisfy the Area/4-law) does not yield (give us) the ecpected tunneling rate: $\\Gamma\\simeq exp(\\Delta S)$, where $\\Delta S$ is the change of black hole entropy, if we compare with the z=1-Lifshitz black hole (BTZ black hole, which satisfies the Area/4-law).
Hawking radiation from z = 3 and z = 1-Lifshitz black holes
Lepe, Samuel; Merello, Bruno
2014-10-01
The Hawking radiation considered as a tunneling process, by using a Hamilton-Jacobi prescription, is discussed for both z = 3 and z = 1-Lifshitz black holes. We have found that the tunneling rate (which is not thermal but related to the change of entropy) for the z = 3-Lifshitz black hole (which does not satisfy the Area/4-law) does not yield (give us) the expected tunneling rate: Γ exp(ΔS), where ΔS is the change of black hole entropy, if we compare with the z = 1-Lifshitz black hole (BTZ black hole, which satisfies the Area/4-law).
Ionizing radiation and lipid peroxidation in human body
Lipids are organic compounds constituting the living cells. Lipid molecules can be disassembled through peroxidative pathways and hydrocarbons can be bred as end-product of lipid peroxidation in vivo. Lipid peroxidation can be started by an indirect effect of ionizing radiation. So a radioinduced cellular damage in human body can be detected by monitoring the production of specific hydrocarbons
Quantum tunneling radiation from self-dual black holes
Silva, C.A.S., E-mail: calex@fisica.ufc.br [Instituto Federal de Educação Ciência e Tecnologia da Paraíba (IFPB), Campus Campina Grande, Rua Tranquilino Coelho Lemos, 671, Jardim Dinamérica I (Brazil); Brito, F.A., E-mail: fabrito@df.ufcg.edu.br [Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraíba (Brazil)
2013-10-01
Black holes are considered as objects that can reveal quantum aspects of spacetime. Loop Quantum Gravity (LQG) is a theory that propose a way to model the quantum spacetime behavior revealed by a black hole. One recent prediction of this theory is the existence of sub-Planckian black holes, which have the interesting property of self-duality. This property removes the black hole singularity and replaces it with another asymptotically flat region. In this work, we obtain the thermodynamical properties of this kind of black holes, called self-dual black holes, using the Hamilton–Jacobi version of the tunneling formalism. Moreover, using the tools of the tunneling approach, we investigate the emission spectrum of self-dual black holes, and investigate if some information about the black hole initial state can be recovered during the evaporation process. Back-reaction effects are included.
Quantum tunneling radiation from self-dual black holes
Silva, C. A. S.; Brito, F. A.
2013-10-01
Black holes are considered as objects that can reveal quantum aspects of spacetime. Loop Quantum Gravity (LQG) is a theory that propose a way to model the quantum spacetime behavior revealed by a black hole. One recent prediction of this theory is the existence of sub-Planckian black holes, which have the interesting property of self-duality. This property removes the black hole singularity and replaces it with another asymptotically flat region. In this work, we obtain the thermodynamical properties of this kind of black holes, called self-dual black holes, using the Hamilton-Jacobi version of the tunneling formalism. Moreover, using the tools of the tunneling approach, we investigate the emission spectrum of self-dual black holes, and investigate if some information about the black hole initial state can be recovered during the evaporation process. Back-reaction effects are included.
Characteristics of Quantum Radiation of Slowly Varying Nonstationary Kerr-Newman Black Holes
Hua, J C; Hua, Jia-Chen; Huang, Yong-Chang
2006-01-01
Quantum radiative characteristics of slowly varying nonstationary Kerr-Newman black holes are investigated by using the method of generalized tortoise coordinate transformation. It is shown that the temperature and the shape of the event horizon of this kind of black holes depend on the time and the angle. Further, we reveal a relationship that is ignored before between thermal radiation and non-thermal radiation, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of particles in non-thermal radiation for slowly varying nonstationary Kerr-Newman black holes. Also, we show that the deduced general results can be degenerated to the known conclusion of stationary Kerr-Newman black holes.
Toward faithful templates for non-spinning binary black holes using the effective-one-body approach
Buonanno, Alessandra; Baker, John G; Centrella, Joan; Kelly, Bernard J; McWilliams, Sean T; van Meter, James R
2007-01-01
We present an accurate approximation of the full gravitational radiation waveforms generated in the merger of non-eccentric systems of two non-spinning black holes. Utilizing information from recent numerical relativity simulations and the natural flexibility of the effective-one-body (EOB) model, we extend the latter so that it can successfully match the numerical relativity waveforms during the last stages of inspiral, merger and ringdown. By ``successfully'' here, we mean with phase differences < 8% of a gravitational-wave cycle accumulated by the end of the ringdown phase, maximizing only over time of arrival and initial phase. We obtain this result by simply adding a 4-post-Newtonian order correction in the EOB radial potential and determining the (constant) coefficient by imposing high-matching performances with numerical waveforms of mass ratios m1/m2 = 1, 3/2, 2 and 4, m1 and m2 being the individual black-hole masses. The final black-hole mass and spin predicted by the numerical simulations are use...
Correction to Hawking Radiation Characteristics of Stationary Demianski-Newman Black Hole
JIANG Qing-Quan; YANG Shu-Zheng
2006-01-01
The pure thermal spectrum in dragging coordinate system and the tunneling radiation characteristics across the event horizon for stationary Demianski-Newman black hole are researched. The result shows that the tunneling rate of the particle is relevant to Bekenstein-Hawking entropy, and the derived radiate spectrum is not strictly pure thermal,but is consistent with underlying unitary theory. Finally, we use the obtained results to reduce to stationary Kerr black hole and static Schwarzschild black hole, and find that only when ignoring the spectrum at higher energies is the tunneling radiation spectrum consistent with Hawking pure thermal one.
Gender and race matter: the importance of considering intersections in Black women's body image.
Capodilupo, Christina M; Kim, Suah
2014-01-01
Traditionally, body image literature has used race as a variable to explain ethnic-specific differences in body satisfaction and the prevalence of eating disorders. Instead of employing race as an explanatory variable, the present study utilized a qualitative method to explore the relationships among race, ethnicity, culture, discrimination, and body image for African American and Black women. The purpose of the study was to gain a deeper understanding of how race and gender interface with and inform body image. Women were recruited through community centers in a major metropolitan city and represented a diversity of ethnicities. In total, 26 women who identified racially as Black (mean age = 26 years) participated in 6 focus groups, which explored body ideals, societal messages, cultural values, racism, and sexism. Narrative data from the focus groups were analyzed using grounded theory. The central category, Body/Self Image, was informed by perceptions of and feelings about not only weight and shape but also hair, skin, and attitude. Three additional categories, each with multiple properties, emerged: Interpersonal Influences, Experiences of Oppression, and Media Messages. These categories interact to explain the central category of Body/Self Image, and an emergent theory is presented. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24188651
$W_\\infty$ Algebras, Hawking Radiation and Information Retention by Stringy Black Holes
Ellis, John; Mavromatos, Nick E.; Nanopoulos, Dimitri V.
2016-01-01
We have argued previously, based on the analysis of two-dimensional stringy black holes, that information in stringy versions of four-dimensional Schwarzschild black holes (whose singular regions are represented by appropriate Wess-Zumino-Witten models) is retained by quantum $W$-symmetries when the horizon area is not preserved due to Hawking radiation. It is key that the exactly-marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole ...
She Had a Name That God Didn’t Give Her: Thinking the Body through Atheistic Black Radical Feminism
Marquis Bey
2015-11-01
Full Text Available The article attempts to demonstrate the necessity of acknowledging the body when considering the current Black Lives Matter movement, give an account of Black female and trans erasure, and ultimately (reaffirm the lived embodiment of Black, female, and trans bodies, all through an atheistic lens. Atheism here, while indeed denying the existence of gods, has as its primary concern affirming life. Too often is theology, as theologian Anthony Pinn says, “a theology of no-body”; thus atheistic feminist Blackness, as understood here, seeks to entrench the body rather than abstract it. Atheistic feminist Blackness reinscribes and affirms the subjectivity and humanity of Black, female, and trans bodies, countering hegemonic discourse that explicitly and implicitly states otherwise. The article’s emphasis of an atheistic posture stems from the prescient words of Catherine Keller: “atheist or agnostic feminists ignore the God-word at their own peril.” Therefore, the Black feminist ideological argument takes the “God-word” seriously, reckons with it, and offers an alternative to a theological tradition that often imbues the body with inherent flaw (sin, abstraction (soul, and erasure of the ontological value of Black, female, and noncisgendered bodies.
N-Body Growth of a Bahcall-Wolf Cusp Around a Black Hole
Preto, M; Spurzem, R; Preto, Miguel; Merritt, David; Spurzem, Rainer
2004-01-01
We present a clear N-body realization of the growth of a Bahcall-Wolf f ~ E^0.25 (rho ~ 1/r^1.75) density cusp around a massive object ("black hole") at the center of a stellar system. Our N-body algorithm incorporates a novel implementation of Mikkola-Aarseth chain regularization to handle close interactions between star and black hole particles. Forces outside the chain were integrated on a GRAPE-6A/8 special-purpose computer with particle numbers up to N=0.25 x 10^6. We compare our N-body results with predictions of the isotropic Fokker-Planck equation and verify that the time dependence of the density (both configuration and phase-space) predicted by the Fokker-Planck equation is well reproduced by the N-body algorithm, for various choices of N and of the black hole mass. Our results demonstrate the feasibility of direct-force integration techniques for simulating the evolution of galactic nuclei on relaxation time scales.
Normal tissue toxicity after small field hypofractionated stereotactic body radiation
Constine Louis S
2008-10-01
Full Text Available Abstract Stereotactic body radiation (SBRT is an emerging tool in radiation oncology in which the targeting accuracy is improved via the detection and processing of a three-dimensional coordinate system that is aligned to the target. With improved targeting accuracy, SBRT allows for the minimization of normal tissue volume exposed to high radiation dose as well as the escalation of fractional dose delivery. The goal of SBRT is to minimize toxicity while maximizing tumor control. This review will discuss the basic principles of SBRT, the radiobiology of hypofractionated radiation and the outcome from published clinical trials of SBRT, with a focus on late toxicity after SBRT. While clinical data has shown SBRT to be safe in most circumstances, more data is needed to refine the ideal dose-volume metrics.
The radiation protection standard recommended by ICRP was evaluated in terms of its suitability for Chinese people. The body height and weight of 100,325 healthy Chinese were measured and anatomical data collected from usable corpses of persons who died by accident or sudden death. The data included the size and weight of certain organs. 18 refs
$W_\\infty$ Algebras, Hawking Radiation and Information Retention by Stringy Black Holes
Ellis, John; Nanopoulos, Dimitri V
2016-01-01
We have argued previously, based on the analysis of two-dimensional stringy black holes, that information in stringy versions of four-dimensional Schwarzschild black holes (whose singular regions are represented by appropriate Wess-Zumino-Witten models) is retained by quantum $W$-symmetries when the horizon area is not preserved due to Hawking radiation. It is key that the exactly-marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole requires a contribution from $W_\\infty$ generators in its vertex function. The latter correspond to delocalised, non-propagating, string excitations that guarantee the transfer of information between the string black hole and external particles. When infalling matter crosses the horizon, these topological states are excited via a process: (Stringy black hole) + infalling matter $\\rightarrow $ (Stringy black hole)$^\\star$, where the black hole is viewed as a stringy state with a specific configuration of $W_\\infty$ charges...
Temperature fields in large radiation-absorbing bodies
Bodies in the vicinity of radiation sources are heated by absorption of radiation energy. Information on the temperature fields in such bodies is often important from the safety point of view, e.g., in connection with possible local melting or with temperature-induced changes in the properties of materials. This paper shows how such temperature fields can be calculated. The theoretical results are supported by experimental findings. For this purpose a large body was equipped with an array of thermocouples and was irradiated in a reactor at Juelich. The paper presents an unidimensional temperature field equation, sufficient for many cases arising in practice, in a form taking into account the decrease in the heat source term in the direction of the radiation, as well as a system of equations for determining three-dimensional temperature fields with any specified boundary conditions. The system is written in a matrix from appropriate for solution by the finite element method. The matrices for a rith-prism finite element, required for practical calculations, are presented explicitly. These matrices make it possible to calculate temperature fields in very extensive bodies. (orig.)
Direct detection of Black Holes via electromagnetic radiation
Sobrinho, J L G
2014-01-01
Many black hole (BH) candidates exist, ranging from supermassive ($\\sim10^{6}$--$10^{10}$ M$_{\\odot}$) to stellar masses ($\\sim 1$--$100$ M$_{\\odot}$), all of them identified by indirect processes. Although there are no known candidate BHs with sub-stellar masses, these might have been produced in the primordial Universe. BHs emit radiation composed of photons, gravitons and, later in their lifes, massive particles. We explored the detection of such BHs with present day masses from $10^{-22}$ M$_{\\odot}$ to $10^{-11}$ M$_{\\odot}$. We determined the maximum distances ($d$) at which the current best detectors should be placed in order to identify such isolated BHs. Broadly, we conclude that in the visible and ultraviolet BHs can be directly detected at $d\\lesssim 10^7$ m while in the X-ray band the distances might reach $\\sim10^8$ m (of the order of the Earth-Moon distance) and in the $\\gamma$-ray band BHs might even be detected from as far as $\\sim 0.1$ pc. Since these results give us realistic hopes of direct...
Hawking Radiation Energy and Entropy from a Bianchi-Smerlak Semiclassical Black Hole
Abdolrahimi, Shohreh
2015-01-01
Eugenio Bianchi and Matteo Smerlak have found a relationship between the Hawking radiation energy and von Neumann entropy in a conformal field emitted by a semiclassical two-dimensional black hole. We compare this relationship with what might be expected for unitary evolution of a quantum black hole in four and higher dimensions. If one neglects the expected increase in the radiation entropy over the decrease in the black hole Bekenstein-Hawking A/4 entropy that arises from the scattering of the radiation by the barrier near the black hole, the relation works very well, except near the peak of the radiation von Neumann entropy and near the final evaporation. These discrepancies are calculated and discussed as tiny differences between a semiclassical treatment and a quantum gravity treatment.
Radiation doses from contaminant aerosol deposition to the human body
Nearly all assessments of radiation doses received following accidental airborne releases have focused on the contributions originating from the plume and from ground deposition. Very little thought has however been given to doses received from deposition directly onto humans. The results of recent experimental investigations of aerosol deposition to and clearance from human skin and clothing have been used to model the doses potentially received in an accident situation. It was found that both the skin dose from β-emitters and the whole body dose from γ-emitters may be significant compared with doses received through other pathways, such as external radiation from the environment. (au)
Hawking Radiation of Dirac Particles in an Arbitrarily Accelerating Kinnersley Black Hole
Wu, S Q
2002-01-01
Quantum thermal effect of Dirac particles in an arbitrarily accelerating Kinnersley black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the advanced time and the angles. The Hawking thermal radiation spectrum of Dirac particles contains a new term which represents the interaction between particles with spin and black holes with acceleration. This spin-acceleration coupling effect is absent from the thermal radiation spectrum of scalar particles.
Yuan, Ye-Fei; Cao, Xinwu; Huang, Lei; Shen, Zhi-Qiang
2009-01-01
In fully general relativity, we calculate the images of the radiatively inefficient accretion flow (RIAF) surrounding a Kerr black hole with arbitrary spins, inclination angles, and observational wavelengths. For the same initial conditions, such as the fixed accretion rate, it is found that the intrinsic size and radiation intensity of the images become larger, but the images become more compact in the inner region, while the size of the black hole shadow decreases with the increase of the b...
Hawking radiation of asymptotically non-flat dyonic black holes in Einstein-Maxwell-dilaton gravity
Slavov, Peter I.; Yazadjiev, Stoytcho S.
2012-01-01
In the present paper we investigate the Hawking radiation of asymptotically non-flat dyonic black holes in 4D Einstein-Maxwell-dilaton gravity in semi-classical approximation. We show that the problem allows an exact analytical treatment and we compute exactly the semi-classical radiation spectrum of both non-extremal and extremal black holes under consideration. In the high frequency regime we find that the Hawking temperature does not agree with the surface gravity when the magnetic charge ...
The existence of the Hawking radiation of the black hole surely affected the space-time. In this paper, using the result which is obtained by the thermodynamics method and applying the semiclassical Einstein equation when the radiation field is existent, it was obtained the static spherically symmetric metric of a Schwarzschild black hole (SBH) surrounded by the radiation field. Using this metric, it was found that the relation between the radiation energy density and the radius pressure is in accordance with the relation of the space-time
Quantum Geometry and Thermal Radiation from Black Holes
Krasnov, Kirill
1997-01-01
A quantum mechanical description of black hole states proposed recently within non-perturbative quantum gravity is used to study the emission and absorption spectra of quantum black holes. We assume that the probability distribution of states of the quantum black hole is given by the ``area'' canonical ensemble, in which the horizon area is used instead of energy, and use Fermi's golden rule to find the line intensities. For a non-rotating black hole, we study the absorption and emission of s...
The Posthuman Body in Jennifer Egan’s “Black Box”
Precup Amelia
2015-12-01
Full Text Available This paper participates in the discussion about the configuration of what is commonly being referred to as ‘the posthuman condition’ by addressing the technological transformation of the human body and the cultural and political inflections of this transformation through the exploration of Jennifer Egan’s “Black Box.” The paper interrogates the implication of the fusion of flesh and technology and the re-conceptualization of the body as information, thus enabling insights into how these changes affect subjectivity, individuality, and the stereotyped understanding of gender hierarchies.
Baco, Sudirman; Harada, Hiroshi; Fukuhara, Riichi
1997-01-01
Since the end of the 1970's, Wagyu producers in southern Kyushu have made efforts in order to improve not only carcass quantity but also carcass quality, introducing a number of AI sires which were produced in another districts that had a hight opinion on carcass quality. A study was conducted to examine effects of such an effort for carcass improvement on the body measurement and reproductivity of a local Japanese Black herd. The records of body measurements and reproductive traits of 1,189 ...
Stereotactic Body Radiation Therapy for Treatment of Spinal Bone Metastasis.
Cihan, Yasemin Benderli
2016-01-01
Stereotactic body radiation therapy (SBRT) appears an effective and safe treatment modality for spinal bone metastasis, which can enhance local control and improve quality of life. Life expectation, predicted fracture risk, localization, quality, size and number of metastasis and presence or absence of nerve compression seem to be important factors in decision-making for treatment. Further studies are needed to identify subsets of patient which will most benefit from treatment. PMID:27039816
Motion of extended bodies in GRT and gravitational radiation
The problem of motion of extended spherically symmetric bodies connected only by gravitational interaction with provision for their gravitational self-radiation is considered in the paper in the framework of GRT. The problem is solved by the method of successive Fock representations in the harmonic coordinate system in the approximation of slow motions and weak fields (v2/C2 approximately U/C2 approximately epsilon2 << 1). With the accuracy up to the fifth-order members over epsilon, inclusive. Equations of motion are derived for two bodies with provision for the reaction of their gravitational radiation. It is shown that the system conservatism is observed up to the fifth-order approximation. But in the second approximation over epsilon only two classical motion integrals exist instead of six ones (the total energy and total momentum ntegrals). The effect of torsion induction is got in the system of initially non-rotatable bodies. It is shown that in the fifth-order approximation the system does not preserve its conservatism due to gravitational radiation. The expression for the energy loss rate is obtained for the system directly from the obtained equations of motion
Low-energy electromagnetic radiation as an indirect probe of black-hole evaporation
Emelyanov, Slava
2016-01-01
We study the influence of black-hole evaporation on light propagation. The framework employed is based on the non-linear QED effective action at one-loop level. We show that the light-cone condition is modified for low-energy radiation due to black-hole evaporation. We discuss conditions under which the phase velocity of this low-energy radiation is greater than $c$. We also compute the modified light-deflection angle, which turns out to be significantly different from the standard GR value for black-hole masses in the range $M_\\text{Pl} \\ll M \\lesssim 10^{19}\\;M_\\text{Pl}$.
W∞ algebras, Hawking radiation, and information retention by stringy black holes
Ellis, John; Mavromatos, Nick E.; Nanopoulos, D. V.
2016-07-01
We have argued previously, based on the analysis of two-dimensional stringy black holes, that information in stringy versions of four-dimensional Schwarzschild black holes (the singular regions of which are represented by appropriate Wess-Zumino-Witten models) is retained by quantum W symmetries when the horizon area is not preserved due to Hawking radiation. It is key that the exactly marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole requires a contribution from W∞ generators in its vertex function. The latter correspond to delocalized, nonpropagating, string excitations that guarantee the transfer of information between the string black hole and external particles. When infalling matter crosses the horizon, these topological states are excited via a process: (stringy black hole) + infalling matter → (stringy black hole)⋆ , where the black hole is viewed as a stringy state with a specific configuration of W∞ charges that are conserved. Hawking radiation is then the reverse process, with conservation of the W∞ charges retaining information. The Hawking radiation spectrum near the horizon of a Schwarzschild or Kerr black hole is specified by matrix elements of higher-order currents that form a phase-space W1 +∞ algebra. We show that an appropriate gauging of this algebra preserves the horizon two-dimensional area classically, as expected because the latter is a conserved Noether charge.
Gastrointestinal Toxicities With Combined Antiangiogenic and Stereotactic Body Radiation Therapy
Pollom, Erqi L.; Deng, Lei [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Pai, Reetesh K. [Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States); Brown, J. Martin; Giaccia, Amato; Loo, Billy W.; Shultz, David B.; Le, Quynh Thu; Koong, Albert C. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Chang, Daniel T., E-mail: dtchang@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States)
2015-07-01
Combining the latest targeted biologic agents with the most advanced radiation technologies has been an exciting development in the treatment of cancer patients. Stereotactic body radiation therapy (SBRT) is an ablative radiation approach that has become established for the treatment of a variety of malignancies, and it has been increasingly used in combination with biologic agents, including those targeting angiogenesis-specific pathways. Multiple reports have emerged describing unanticipated toxicities arising from the combination of SBRT and angiogenesis-targeting agents, particularly of late luminal gastrointestinal toxicities. In this review, we summarize the literature describing these toxicities, explore the biological mechanism of action of toxicity with the combined use of antiangiogenic therapies, and discuss areas of future research, so that this combination of treatment modalities can continue to be used in broader clinical contexts.
Body and diet composition of sympatric black and grizzly bears in the Greater Yellowstone Ecosystem
Schwartz, Charles C.; Fortin, Jennifer K.; Teisberg, Justin E.; Haroldson, Mark A.; Servheen, Christopher; Robbins, Charles T.; van Manen, Frank T.
2013-01-01
The Greater Yellowstone Ecosystem (GYE) has experienced changes in the distribution and availability of grizzly bear (Ursus arctos) food resources in recent decades. The decline of ungulates, fish, and whitebark pine seeds (Pinus albicaulis) has prompted questions regarding their ability to adapt. We examined body composition and diet of grizzly bears using bioelectrical impedance and stable isotopes to determine if 1) we can detect a change in diet quality associated with the decline in either ungulates or whitebark pine, and 2) the combined decline in ungulates, fish, and pine seeds resulted in a change in grizzly bear carrying capacity in the GYE. We contrasted body fat and mass in grizzly bears with a potential competitor, the American black bear (Ursus americanus), to address these questions. Grizzly bears assimilated more meat into their diet and were in better body condition than black bears throughout the study period, indicating the decline in ungulate resources did not affect grizzly bears more than black bears. We also found no difference in autumn fat levels in grizzly bears in years of good or poor pine seed production, and stable isotope analyses revealed this was primarily a function of switching to meat resources during poor seed-producing years. This dietary plasticity was consistent over the course of our study. We did not detect an overall downward trend in either body mass or the fraction of meat assimilated into the diet by grizzly bears over the past decade, but we did detect a downward trend in percent body fat in adult female grizzly bears after 2006. Whether this decline is an artifact of small sample size or due to the population reaching the ecological carrying capacity of the Yellowstone ecosystem warrants further investigation.
Hawking Radiation from Elko Particles Tunnelling across Black Strings Horizon
da Rocha, Roldao
2014-01-01
We apply the tunnelling method for the emission and absorption of Elko particles in the event horizon of a black string solution. We show that Elko particles are emitted at the expected Hawking temperature from black strings, but with a quite different signature with respect to the Dirac particles. We employ the Hamilton-Jacobi technique to black hole tunnelling, by applying the WKB approximation to the coupled system of Dirac-like equations governing the Elko particle dynamics. As a typical signature, different Elko particles are shown to produce the same standard Hawking temperature for black strings. However we prove that they present the same probability irrespective of outgoing or ingoing the black hole horizon. It provides a typical signature for mass dimension one fermions, that is different from the mass dimension three halves fermions inherent to Dirac particles, as different Dirac spinor fields have distinct inward and outward probability of tunnelling.
Hawking radiation of Reissner-Nordstrom-de Sitter black hole by Hamilton-Jacobi method
Hossain, M Ilias
2013-01-01
In Refs. (M. Atiqur Rahman, M. Ilias Hossain (2012) Phys. Lett. B {\\bf 712} 1), we have developed Hamilton-Jacobi method for dynamical spacetime and discussed Hawking radiation of Schwarzschild-de Sitter black hole by massive particle tunneling method. In this letter, we have investigated the hawking purely thermal and nonthermal radiations of Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole. We have considered energy and angular momentum as conserved and shown that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results we have obtained for RNdS black hole is also in accordance with Parikh and Wilczek\\rq s opinion and recovered the new result for Hawking radiation of RNdS black hole.
Quantum Tunnelling for Hawking Radiation from Both Static and Dynamic Black Holes
Subenoy Chakraborty
2014-01-01
Full Text Available The paper deals with Hawking radiation from both a general static black hole and a nonstatic spherically symmetric black hole. In case of static black hole, tunnelling of nonzero mass particles is considered and due to complicated calculations, quantum corrections are calculated only up to the first order. The results are compared with those for massless particles near the horizon. On the other hand, for dynamical black hole, quantum corrections are incorporated using the Hamilton-Jacobi method beyond semiclassical approximation. It is found that different order correction terms satisfy identical differential equation and are solved by a typical technique. Finally, using the law of black hole mechanics, a general modified form of the black hole entropy is obtained considering modified Hawking temperature.
Thermodynamic analysis of a Schwarzschild black hole fed by cosmic microwave background radiation
The analysis of black holes fed by the omnipresent Cosmic Microwave Background Radiation (CMBR) constitutes benchmark cases. The rate of energy and entropy variation of a Schwarzschild black hole fed by CMBR is analytically obtained. The entropy analysis revealed that there is a higher value of black hole's critical mass than that obtained from an energy analysis, which is needed for its existence with high probability. At this minimum value of mass of the Schwarzschild black hole, the entropy generated due to its existence becomes positive. The black hole's negentropy and the difference between its exit and inlet specific entropies are shown to more importantly correlate with its event horizon area than the black hole's entropy. (orig.)
Thermodynamic analysis of a Schwarzschild black hole fed by cosmic microwave background radiation
Mahulikar, Shripad P.; Herwig, Heinz
2013-01-01
The analysis of black holes fed by the omnipresent Cosmic Microwave Background Radiation (CMBR) constitutes benchmark cases. The rate of energy and entropy variation of a Schwarzschild black hole fed by CMBR is analytically obtained. The entropy analysis revealed that there is a higher value of black hole's critical mass than that obtained from an energy analysis, which is needed for its existence with high probability. At this minimum value of mass of the Schwarzschild black hole, the entropy generated due to its existence becomes positive. The black hole's negentropy and the difference between its exit and inlet specific entropies are shown to more importantly correlate with its event horizon area than the black hole's entropy.
Thermodynamic analysis of a Schwarzschild black hole fed by cosmic microwave background radiation
Mahulikar, Shripad P. [Hamburg University of Technology, Institut fuer Thermofluiddynamik (M-21), Hamburg (Germany); Indian Institute of Technology Bombay, Department of Aerospace Engineering, P.O. IIT Powai, Mumbai (India); Herwig, Heinz [Hamburg University of Technology, Institut fuer Thermofluiddynamik (M-21), Hamburg (Germany)
2013-01-15
The analysis of black holes fed by the omnipresent Cosmic Microwave Background Radiation (CMBR) constitutes benchmark cases. The rate of energy and entropy variation of a Schwarzschild black hole fed by CMBR is analytically obtained. The entropy analysis revealed that there is a higher value of black hole's critical mass than that obtained from an energy analysis, which is needed for its existence with high probability. At this minimum value of mass of the Schwarzschild black hole, the entropy generated due to its existence becomes positive. The black hole's negentropy and the difference between its exit and inlet specific entropies are shown to more importantly correlate with its event horizon area than the black hole's entropy. (orig.)
Quantum Tunnelling for Hawking Radiation from Both Static and Dynamic Black Holes
The paper deals with Hawking radiation from both a general static black hole and a nonstatic spherically symmetric black hole. In case of static black hole, tunnelling of nonzero mass particles is considered and due to complicated calculations, quantum corrections are calculated only up to the first order. The results are compared with those for massless particles near the horizon. On the other hand, for dynamical black hole, quantum corrections are incorporated using the Hamilton-Jacobi method beyond semiclassical approximation. It is found that different order correction terms satisfy identical differential equation and are solved by a typical technique. Finally, using the law of black hole mechanics, a general modified form of the black hole entropy is obtained considering modified Hawking temperature
Secondary radiation dose during high-energy total body irradiation
The goal of this work was to assess the additional dose from secondary neutrons and γ-rays generated during total body irradiation (TBI) using a medical linac X-ray beam. Nuclear reactions that occur in the accelerator construction during emission of high-energy beams in teleradiotherapy are the source of secondary radiation. Induced activity is dependent on the half-lives of the generated radionuclides, whereas neutron flux accompanies the treatment process only. The TBI procedure using a 18 MV beam (Clinac 2100) was considered. Lateral and anterior-posterior/posterior-anterior fractions were investigated during delivery of 2 Gy of therapeutic dose. Neutron and photon flux densities were measured using neutron activation analysis (NAA) and semiconductor spectrometry. The secondary dose was estimated applying the fluence-to-dose conversion coefficients. The main contribution to the secondary dose is associated with fast neutrons. The main sources of γ-radiation are the following: 56Mn in the stainless steel and 187W of the collimation system as well as positron emitters, activated via (n,γ) and (γ,n) processes, respectively. In addition to 12 Gy of therapeutic dose, the patient could receive 57.43 mSv in the studied conditions, including 4.63 μSv from activated radionuclides. Neutron dose is mainly influenced by the time of beam emission. However, it is moderated by long source-surface distances (SSD) and application of plexiglass plates covering the patient body during treatment. Secondary radiation gives the whole body a dose, which should be taken into consideration especially when one fraction of irradiation does not cover the whole body at once. (orig.)
Hajdukovic, D
2006-01-01
We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.
Bodies in a Frame: Black British, Working Class, Teenage Femininity and the Role of the Dance Class
Camilla Stanger
2013-01-01
Historically the working class, black, female body has been defined by its sexuality and socially constructed as an object for heterosexual consumption; this article is concerned with how this manifests itself for young British women in educational settings today. I will argue that this historical bodily construction has been compounded for young women in this context by a contemporary popular culture which frames, glamorises and hetero-sexualises black female bodies. Drawing on the work of J...
a Method to Study the Hawking Radiation of the Kerr Black Hole
Chen, Deyou; Yang, Shuzheng
Using the Hamilton-Jacobi method, we discuss the Hawking radiation of the Kerr black hole. The result shows when the self-gravitational interaction as well as the conservation of energy and angular momentum are taken into account, the radiation spectrum deviates from the purely thermal one and the tunneling probability is related to the change of Bekenstein-Hawking entropy, which is in accordance with Parikh and Wilczek's result and gives a method to study the Hawking radiation of the black hole.
In this paper, we consider the gravitational radiation generated by the collision of highly relativistic particles with rotating Kerr black holes. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra, and total energy radiated during this process. We show that the gravitational spectrum for high-energy collisions has definite characteristic universal features, which are independent of the spin of the colliding objects. We also discuss the possible connections between these results and black-hole-black-hole collisions at the speed of light. Our results show that during the high-speed collision of a nonrotating hole with a rotating one, at most 35% of the total energy can get converted into gravitational waves. This 35% efficiency occurs only in the most optimistic situation, that of a zero impact parameter collision, along the equatorial plane, with an almost extreme Kerr black hole. In the general situation, the total gravitational energy radiated is expected to be much less, especially if the impact parameter increases. Thus, if one is able to produce black holes at the CERN Large Hadron Collider, at most 35% of the partons' energy should be emitted during the so-called balding phase. This energy will be missing, since we do not have gravitational wave detectors able to measure such amplitudes. The collision at the speed of light between one rotating black hole and a nonrotating one or two rotating black holes turns out to be the most efficient gravitational wave generator in the Universe
Radiation of charged black holes and modified dispersion relation
Kamali, A. D.; Pedram, P.
2016-05-01
We investigate the effects of a modified dispersion relation proposed by Majhi and Vagenas on the Reissner-Nordström black hole thermodynamics in a universe with large extra dimensions. It is shown that entropy, temperature and heat capacity receive new corrections and charged black holes in this framework have less degrees of freedom and decay faster compared to black holes in the Hawking picture. We also study the emission rate of black hole and compare our results with other quantum gravity approaches. In this regard, the existence of the logarithmic prefactor and the relation between dimensions and charge are discussed. This procedure is not only valid for a single horizon spacetime but it is also valid for the spacetimes with inner and outer horizons.
Energetic Gamma Radiation from Rapidly Rotating Black Holes
Hirotani, Kouichi
2015-01-01
Supermassive black holes are believed to be the central power house of active galactic nuclei. Applying the pulsar outer-magnetospheric particle accelerator theory to black-hole magnetospheres, we demonstrate that an electric field is exerted along the magnetic field lines near the event horizon of a rotating black hole. In this particle accelerator (or a gap), electrons and positrons are created by photon-photon collisions and accelerated in the opposite directions by this electric field, efficiently emitting gamma-rays via curvature and inverse-Compton processes. It is shown that a gap arises around the null charge surface formed by the frame-dragging effect, provided that there is no current injection across the gap boundaries. The gap is dissipating a part of the hole's rotational energy, and the resultant gamma-ray luminosity increases with decreasing plasma accretion from the surroundings. Considering an extremely rotating supermassive black hole, we show that such a gap reproduces the significant very-...
Radiation of Charged Black Holes and Modified Dispersion Relation
Kamali, A D
2016-01-01
We investigate the effects of a modified dispersion relation proposed by Majhi and Vagenas on the Reissner-Nordstr\\"{o}m black hole thermodynamics in a universe with large extra dimensions. It is shown that entropy, temperature and heat capacity receive new corrections and charged black holes in this framework have less degrees of freedom and decay faster compared to black holes in the Hawking picture. We also study the emission rate of black hole and compare our results with other quantum gravity approaches. In this regard, the existence of the logarithmic prefactor and the relation between dimensions and charge are discussed. This procedure is not only valid for a single horizon spacetime but it is also valid for the spacetimes with inner and outer horizons.
Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)
If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this Letter we revisit some phenomenological signatures of black hole production in TeV-gravity theories. We show that the bulk-to-brane ratio of black hole energy loss during the Hawking evaporation phase depends crucially on the black hole greybody factors and on the particle degrees of freedom. Since the greybody factors have not yet been calculated in the literature, and the particle content at trans-Planckian energies is not known, it is premature to claim that the black hole emits mainly on the brane. We also revisit the decay time and the multiplicity of the decay products of black hole evaporation. We give general formulae for black hole decay time and multiplicity. We find that the number of particles produced during the evaporation phase may be significantly lower than the average multiplicity which has been used in the past literature
Kelly, N. R.; Bulik, C. M.; Mazzeo, S. E.
2011-01-01
Silhouette measures are one approach to assessing body dissatisfaction in children, although little is known about their use among racially diverse, overweight girls seeking weight-loss treatment. This study assessed racial differences in body dissatisfaction and body size perceptions of 58 girls (ages 6–11, 66% Black, 34% White) participating in a randomized trial for pediatric overweight. Body dissatisfaction did not differ between races; 99% of girls reported an ideal figure smaller than t...
The black liquor of straw plug was treated by electron beam or γ-ray radiation. The relationship between the viscosity of the black liquor of straw plug and the radiation beam type, the irradiated dose, the temperature of the black liquor at irradiation time and the concentration of the solid state matter in the black liquor was investigated. The result shows that the radiation treatment makes the organic big molecular of the black liquor decomposed, the environmental loading factor of the black liquor reduced; after an irradiation of 20 kGy, the viscosity of the black liquor of straw plug with 30% solid state matter is reduced by 50%, the property of vaporization is obviously improved, but the calorific value of the black liquor has almost no change
Hod, Shahar
2015-01-01
The holographic principle has taught us that, as far as their entropy content is concerned, black holes in $(3+1)$-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat $(2+1)$-dimensional spacetimes. In this essay we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner-Nordstr\\"om black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine $(3+1)$-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the $(3+1)$-dimensional black holes effectively behave as p...
Asymmetry of Hawking Radiation of Dirac Particles in a Charged Vaidya - de Sitter Black Hole
Wu, S Q
2001-01-01
The Hawking radiation of Dirac particles in a charged Vaidya - de Sitter black hole is investigated by using the method of generalized tortoise coordinate transformation. It is shown that the Hawking radiation of Dirac particles does not exist for $P_1, Q_2$ components, but for $P_2, Q_1$ components it does. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles.
On neutral scalar radiation by a massive orbiting star in extremal Kerr-Newman black hole
Xu, Xiao-Bao; Bai, Nan; Gao, Yi-Hong [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing (China)
2015-06-15
We extend the work of 1401.3746 about gravitational waves by a massive orbiting star in an extremal Kerr black hole to an extremal Kerr-Newman black hole for the scalar radiation, and we still find that it has a CFT interpretation from Kerr-Newman/CFT, because our scalar is neutral although the black hole is a charged one. When the charge of black hole is zero, we can get the result of 1401.3746, so we give a new evidence on Kerr-Newman/CFT. In addition, we investigate on electromagnetic radiation with Kerr/CFT in detail which isn't given by 1401.3746. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Information-carrying Hawking radiation and the number of microstate for a black hole
Qing-yu Cai
2016-04-01
Full Text Available We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein–Hawking entropies for Schwarzschild black holes and Reissner–Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner–Nordström black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein–Hawking entropy of extremal black holes in the semiclassical limit.
Information-carrying Hawking radiation and the number of microstate for a black hole
Cai, Qing-yu; Sun, Chang-pu; You, Li
2016-04-01
We present a necessary and sufficient condition to falsify whether a Hawking radiation spectrum indicates unitary emission process or not from the perspective of information theory. With this condition, we show the precise values of Bekenstein-Hawking entropies for Schwarzschild black holes and Reissner-Nordström black holes can be calculated by counting the microstates of their Hawking radiations. In particular, for the extremal Reissner-Nordström black hole, its number of microstate and the corresponding entropy we obtain are found to be consistent with the string theory results. Our finding helps to refute the dispute about the Bekenstein-Hawking entropy of extremal black holes in the semiclassical limit.
On neutral scalar radiation by a massive orbiting star in extremal Kerr-Newman black hole
We extend the work of 1401.3746 about gravitational waves by a massive orbiting star in an extremal Kerr black hole to an extremal Kerr-Newman black hole for the scalar radiation, and we still find that it has a CFT interpretation from Kerr-Newman/CFT, because our scalar is neutral although the black hole is a charged one. When the charge of black hole is zero, we can get the result of 1401.3746, so we give a new evidence on Kerr-Newman/CFT. In addition, we investigate on electromagnetic radiation with Kerr/CFT in detail which isn't given by 1401.3746. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Growth of Accreting Supermassive Black Hole Seeds and Neutrino Radiation
Gagik Ter-Kazarian
2015-01-01
Full Text Available In the framework of microscopic theory of black hole (MTBH, which explores the most important processes of rearrangement of vacuum state and spontaneous breaking of gravitation gauge symmetry at huge energies, we have undertaken a large series of numerical simulations with the goal to trace an evolution of the mass assembly history of 377 plausible accreting supermassive black hole seeds in active galactic nuclei (AGNs to the present time and examine the observable signatures today. Given the redshifts, masses, and luminosities of these black holes at present time collected from the literature, we compute the initial redshifts and masses of the corresponding seed black holes. For the present masses MBH/M⊙≃1.1×106 to 1.3×1010 of 377 black holes, the computed intermediate seed masses are ranging from MBHSeed/M⊙≃26.4 to 2.9×105. We also compute the fluxes of ultrahigh energy (UHE neutrinos produced via simple or modified URCA processes in superdense protomatter nuclei. The AGNs are favored as promising pure UHE neutrino sources, because the computed neutrino fluxes are highly beamed along the plane of accretion disk, peaked at high energies, and collimated in smaller opening angle (θ≪1.
Konstantinidis, Symeon; Amaro-Seoane, Pau; Kokkotas, Kostas D.
2013-09-01
Context. Unlike supermassive and stellar-mass black holes (SBHs), the existence of intermediate-mass black holes (IMBHs) with masses ranging between 102-5 M⊙ has not yet been confirmed. The main problem in the detection is that the innermost stellar kinematics of globular clusters (GCs) or small galaxies, the possible natural loci to IMBHs, are very difficult to resolve. However, if IMBHs reside in the centre of GCs, a possibility is that they interact dynamically with their environment. A binary formed with the IMBH and a compact object of the GC would naturally lead to a prominent source of gravitational radiation, detectable with future observatories. Aims: We use N-body simulations to study the evolution of GCs containing an IMBH and calculate the gravitational radiation emitted from dynamically formed IMBH-SBH binaries and the possibility that the IMBH escapes the GC after an IMBH-SBH merger. Methods: We ran for the first time direct-summation integrations of GCs with an IMBH including the dynamical evolution of the IMBH with the stellar system and relativistic effects, such as energy loss in gravitational waves (GWs) and periapsis shift, and gravitational recoil. Results: We find in one of our models an intermediate mass-ratio inspiral (IMRI), which leads to a merger with a recoiling velocity higher than the escape velocity of the GC. The GWs emitted fall in the range of frequencies that a LISA-like observatory could detect, like the European eLISA or with mission options considered in the recent preliminary mission study conducted in China. The merger has an impact on the global dynamics of the cluster, as an important heating source is removed when the merged system leaves the GC. The detection of one IMRI would constitute a test of GR, as well as an irrefutable proof of the existence of IMBHs.
Jiang Qing-Quan; Yang Shu-Zheng; Wu Shuang-Qing
2006-01-01
This paper extends Parikh-Wilzcek's recent work, which treats the Hawking radiation as a semi-classical tunnelling process from the event horizon of four dimensional Schwarzshild and Reissner-Nordstr(o)m black holes, to that of arbitrarily dimensional Reissner-Nordstr(o)m de Sitter black hole. The result shows that the tunnelling rate is related to the change of Bekenstein-Hawking entropy and the factually radiant spectrum is no longer precisely thermal after taking the dynamical black hole background and energy conservation into account, but is consistent with the underlying unitary theory and then satisfies the first law of the black hole thermodynamics. Meanwhile, in Parikh-Wilzcek's framework, this paper points out that the information conservation is only suitable for the reversible process but in highly unstable evaporating black hole (irreversible process) the information loss is possible.
General radiation via tunneling in Kerr and Kerr-Newman black holes
2008-01-01
Hawking radiation can be viewed as a process of quantum tunneling near the black hole horizon. When a particle with angular momentum L≠ω a tunnels across the event horizon of Kerr or Kerr-Newman black hole, the angular momentum per unit mass a should be changed. The emission rate of the massless particles under this general case is calculated, and the result is consistent with an underlying unitary theory.
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)
2015-09-15
We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
Sakalli, I.; Ovgun, A.
2015-09-01
We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton-Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.
Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole
We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair
Hawking radiation from a BTZ black hole viewed as Landauer transport
Zhou, Shi-Wei; Zeng, Xiao-Xiong; Liu, Wen-Biao
2011-01-01
Viewing Hawking radiation as a 1D single quantum channel Landauer transport process, Nation et al calculated the energy flux and entropy flux from a Schwarzschild black hole without chemical potential. To generalize the method to the case with chemical potential, a rotating charged and non-charged BTZ black hole is investigated. Energy flux and entropy flux obtained are consistent with that from anomaly theory. The maximum energy flux and entropy flux are independent on the statistics of boso...
Sakalli, I.
2016-01-01
Hawking radiation of charged massive spin-0 particles are studied in the gravitational, electromagnetic, dilaton, and axion fields of rotating linear dilaton black holes. In this geometry, we separate the covariant Klein--Gordon equation into radial and angular parts and obtain the exact solutions of both the equations in terms of the confluent Heun functions. Using the radial solution, we analyze the behavior of the wave solutions near the event horizon of the rotating linear dilaton black h...
On Hawking Radiation from a Charged Black Hole of Heterotic String Theory
We investigate the Hawking radiation of a GMGHS charged black hole from the heterotic string scenario by the massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein–Hawking entropy and the derived emission spectrum does not deviate from the pure thermal spectrum of Schwrzschild's black hole
General radiation via tunneling in Kerr and Kerr-Newman black holes
GAO Li; LIU WenBiao
2008-01-01
Hawking radiation can be viewed as a process of quantum tunneling near the black hole horizon. When a particle with angular momentum L≠ωa tunnels across the event horizon of Kerr or Kerr-Newman black hole, the angular momentum per unit mass a should be changed. The emission rate of the massless particles under this general case is calculated, and the result is consistent with an underlying unitary theory.
Hawking radiation from an acoustic black hole on an ion ring.
Horstmann, B; Reznik, B; Fagnocchi, S; Cirac, J I
2010-06-25
In this Letter we propose to simulate acoustic black holes with ions in rings. If the ions are rotating with a stationary and inhomogeneous velocity profile, regions can appear where the ion velocity exceeds the group velocity of the phonons. In these regions phonons are trapped like light in black holes, even though we have a discrete field theory and a nonlinear dispersion relation. We study the appearance of Hawking radiation in this setup and propose a scheme to detect it. PMID:20867352
Hawking Radiation of Dirac Particles in an Arbitrarily Accelerating Kinnersley Black Hole
Wu, S Q; Cai, X.
2002-01-01
Quantum thermal effect of Dirac particles in an arbitrarily accelerating Kinnersley black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the advanced time and the angles. The Hawking thermal radiation spectrum of Dirac particles contains a new term which represents the interaction between particles with spin and black holes with acceleration. This spin-acceleration coupling effect...
Radiating black holes in Einstein-Maxwell-dilaton theory
Aniceto, Pedro; Rocha, Jorge V
2015-01-01
We construct exact, time-dependent, black hole solutions of Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling, a. For a=1 this theory arises as the four-dimensional low-energy effective description of heterotic string theory. These solutions represent electrically charged, spherically symmetric black holes emitting or absorbing charged null dust and generalize the Vaidya and Bonnor-Vaidya solutions of general relativity and of Einstein-Maxwell theory, respectively. The a=1 case stands out as special, in the sense that it is the only choice of the coupling that allows for a time-dependent dilaton field in this class of solutions. As a by-product, we prove that an electrically charged black hole in this theory cannot be overcharged by bombarding it with a stream of electrically charged null dust. This provides an example of cosmic censorship observance in a string theory setting.
Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie
2016-06-17
The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped. PMID:27367380
Information Loss and Tunneling Radiation of the Non-Stationary Dilaton-Maxwell Black Hole
Chen, Deyou; Yang, Shuzheng
Taking the self-gravitational interaction and unfixed background space-time into account, we discuss the tunneling radiation of the Dilaton-Maxwell black hole by the Hamilton-Jacobi method. The result shows that the tunneling rate is related not only to the change of Bekenstein-Hawking entropy, but also to a subtle integral about the black hole mass, which does not satisfy the unitary theory and is different from Parikh and Wilczek's result. This implies that information loss in black hole evaporation is possible.
Currently there is a lack of young academics in the nuclear field especially in the field of radiation protection RP. One of the reasons is the very small number of students in the so called STEM subjects (science, technology, engineering and mathematics) which distribute among the different topics in these fields. One important task to overcome the foreseeable shortage of RP professionals is to attract pupils to this field. In routine monitoring the whole body counter of the Institute of Radiation Research (ISF) is used to identify and quantify radioactive materials that are incorporated in the human body using the technique of gamma spectroscopy. The in-vivo monitoring lab participates in activities for pupils at school level, e.g. Kinderuniversitaet, practical studies of secondary level pupils and 'Girls day'. Pupils that come to the lab are ages 14 to 18. The whole body counter is an optimal tool for these children to experience (natural) radioactivity and radiation protection issues. First pupils get a short introduction on radioactivity and gamma spectroscopy at a level adjusted to their current knowledge. After this they are measuring themselves in the whole body counter. A routine measurement of 300 s is able to show the natural occurring K-40 in their bodies. After their own measurements they do calibration measurements using a bottle phantom with a set up adjusted to their own body weights. The bottle phantom is filled with a potassium chloride (KCl) solution and contains no other radioactivity than the natural K-40 content of the KCl. Thus no further radiation protection measures need to be taken for using this phantom. A simple Excel-Sheet is then used to estimate their own K-40 activity by comparing the spectra of their measurement to the ones of the calibration measurements. This 'hands on' experience and the connection of radiation and their own bodies often is a 'eureka' effect and opens discussion on preconceptions of radiation and the need of RP
Hawking radiation as tunneling of vector particles from Kerr-Newman black hole
Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.
2016-03-01
In this paper, by applying the WKB approximation and Hamilton-Jacobi ansatz to the Proca equation, we investigate the tunneling of vector bosons across the event horizon of Kerr-Newman black hole and also the resulting vector particles' Hawking radiation. Universality of the properties of the emitted spectra of different types of particles is established for Kerr-Newman black hole. The coordinate problem for Hawking radiation of the vector particles is also investigated using three coordinate systems. The thermal spectrum of the radiated vector bosons determined using a direct computation corresponds to a temperature which is twice the Hawking temperature of Kerr-Newman black hole for scalar particles. If the well behaved Eddington coordinate system and Painleve coordinate system are used, the correct result of Hawking temperature is obtained. The reason for the discrepancy in the results of naive coordinate and well behaved coordinates is also discussed.
Sadowski, A; Narayan, R; Abarca, D; McKinney, J C
2016-01-01
We present a numerical method which evolves a two-temperature, magnetized, radiative, accretion flow around a black hole, within the framework of general relativistic radiation magnetohydrodynamics. As implemented in the code KORAL, the gas consists of two sub-components -- ions and electrons -- which share the same dynamics but experience independent, relativistically consistent, thermodynamical evolution. The electrons and ions are heated independently according to a standard prescription from the literature for magnetohydrodynamical turbulent dissipation. Energy exchange between the particle species via Coulomb collisions is included. In addition, electrons gain and lose energy and momentum by absorbing and emitting synchrotron and bremsstrahlung radiation, and through Compton scattering. All evolution equations are handled within a fully covariant framework in the relativistic fixed-metric spacetime of the black hole. Numerical results are presented for five models of low luminosity black hole accretion. ...
Tidal disruption rate of stars by supermassive black holes obtained by direct N-body simulations
Brockamp, M; Kroupa, P
2011-01-01
The disruption rate of stars by supermassive black holes (SMBHs) is calculated numerically with a modified version of Aarseth's NBODY6 code. The initial stellar distribution around the SMBH follows a S\\'{e}rsic n=4 profile representing bulges and early type galaxies. In order to infer relaxation driven effects and to increase the statistical significance, a very large set of N-body integrations with different particle numbers N, ranging from 10^{3} to 0.5 \\cdot 10^{6} particles, is performed. Three different black hole capture radii are taken into account, enabling us to scale these results to a broad range of astrophysical systems with relaxation times shorter than one Hubble time, i.e. for SMBHs up to M_bh \\approx 10^{7} M_sun. The computed number of disrupted stars are driven by diffusion in angular momentum space into the loss cone of the black hole and the rate scales with the total number of particles as dN/dt \\propto N^{b}, where b is as large as 0.83. This is significantly steeper than the expected sc...
P Bodiba
2008-09-01
Full Text Available The study investigated the relationship between body mass index and self-concept among adolescent black female university students. The study used a mixed research design (quantitative and qualitative methods. Media images of handsome faces and beautiful bodies are used to sell almost everything, from clothes and cosmetic to luncheon, meats, and so on. These images reinforce the western cultural stereotype that women should be thin and shapely to be attractive. Thus, as some girls go through puberty they may become dissatisfied with their weight, and to a lesser extent, with their shape, thus, developing low self-concept or imae of themselves. It is in this context that the study was conceptualised.
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
Wang, Peng; Yang, Haitang; Ying, Shuxuan
2016-01-01
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass mp. The corrections to the Hawking temperature are calculated for massive and charged particles to {O}( mp^{-2}) and neutral and massless particles with λ =0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation.
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
Wang, Peng; Yang, Haitang; Ying, Shuxuan [Sichuan University, Center for Theoretical Physics, College of Physical Science and Technology, Chengdu (China)
2016-01-15
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass m{sub p}. The corrections to the Hawking temperature are calculated for massive and charged particles to O(m{sub p}{sup -2}) and neutral and massless particles with λ = 0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation. (orig.)
Black hole radiation with modified dispersion relation in tunneling paradigm: free-fall frame
Due to the exponential high gravitational red shift near the event horizon of a black hole, it might appear that the Hawking radiation would be highly sensitive to some unknown high energy physics. To study the effects of any unknown physics at the Planck scale on the Hawking radiation, the dispersive field theory models have been proposed, which are variations of Unruh's sonic black hole analogy. In this paper, we use the Hamilton-Jacobi method to investigate the dispersive field theory models. The preferred frame is the free-fall frame of the black hole. The dispersion relation adopted agrees with the relativistic one at low energy but is modified near the Planck mass mp. The corrections to the Hawking temperature are calculated for massive and charged particles to O(mp-2) and neutral and massless particles with λ = 0 to all orders. The Hawking temperature of radiation agrees with the standard one at the leading order. After the spectrum of radiation near the horizon is obtained, we use the brick wall model to compute the thermal entropy of a massless scalar field near the horizon of a 4D spherically symmetric black hole and a 2D one. Finally, the luminosity of a Schwarzschild black hole is calculated by using the geometric optics approximation. (orig.)
Hawking radiation of Schwarzschild-de Sitter black hole by Hamilton-Jacobi method
Rahman, M. Atiqur, E-mail: atirubd@yahoo.com [Department of Applied Mathematics, Rajshahi University (Bangladesh); Hossain, M. Ilias, E-mail: ilias_math@yahoo.com [Department of Mathematics, Rajshahi University, Rajshahi, 6205 (Bangladesh)
2012-05-30
We investigate the Hawking radiation of Schwarzschild-de Sitter (SdS) black hole by massive particles tunneling method. We consider the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles and show that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum when energy and angular momentum are conserved. Our result is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SdS black hole.