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

Abstract

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

Authors:
 [1]; ;  [2];  [1];  [3]
  1. Department of Mathematical Sciences, University of Durham, Science Site, South Road, Durham DH1 3LE (United Kingdom)
  2. Division of Theoretical Physics, Department of Physics, University of Ioannina, Ioannina GR-45110 (Greece)
  3. (Greece)
Publication Date:
OSTI Identifier:
21020412
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevD.75.084043; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ABSORPTION; ANALYTICAL SOLUTION; BLACK HOLES; BRANES; COMPARATIVE EVALUATIONS; COSMOLOGY; DEGREES OF FREEDOM; PROBABILITY; QUANTUM FIELD THEORY; SCALAR FIELDS; TOTAL CROSS SECTIONS

Citation Formats

Creek, S., Efthimiou, O., Tamvakis, K., Kanti, P., and Division of Theoretical Physics, Department of Physics, University of Ioannina, Ioannina GR-45110. Greybody factors for brane scalar fields in a rotating black hole background. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.084043.
Creek, S., Efthimiou, O., Tamvakis, K., Kanti, P., & Division of Theoretical Physics, Department of Physics, University of Ioannina, Ioannina GR-45110. Greybody factors for brane scalar fields in a rotating black hole background. United States. doi:10.1103/PHYSREVD.75.084043.
Creek, S., Efthimiou, O., Tamvakis, K., Kanti, P., and Division of Theoretical Physics, Department of Physics, University of Ioannina, Ioannina GR-45110. Sun . "Greybody factors for brane scalar fields in a rotating black hole background". United States. doi:10.1103/PHYSREVD.75.084043.
@article{osti_21020412,
title = {Greybody factors for brane scalar fields in a rotating black hole background},
author = {Creek, S. and Efthimiou, O. and Tamvakis, K. and Kanti, P. and Division of Theoretical Physics, Department of Physics, University of Ioannina, Ioannina GR-45110},
abstractNote = {We study the evaporation of (4+n)-dimensional rotating black holes into scalar degrees of freedom on the brane. We calculate the corresponding absorption probabilities and cross sections obtaining analytic solutions in the low-energy regime and compare the derived analytic expressions to numerical results, with very good agreement. We then consider the high-energy regime, construct an analytic high-energy solution to the scalar-field equation by employing a new method, and calculate the absorption probability and cross section for this energy regime, finding again a very good agreement with the exact numerical results. We also determine the high-energy asymptotic value of the total cross section and compare it to the analytic results derived from the application of the geometrical optics limit.},
doi = {10.1103/PHYSREVD.75.084043},
journal = {Physical Review. D, Particles Fields},
number = 8,
volume = 75,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • We study the emission of fermion and gauge boson degrees of freedom on the brane by a rotating higher-dimensional black hole. Using matching techniques, for the near-horizon and far-field regime solutions, we solve analytically the corresponding field equations of motion. From this, we derive analytical results for the absorption probabilities and Hawking radiation emission rates, in the low-energy and low-rotation case, for both species of fields. We produce plots of these, comparing them to existing exact numerical results with very good agreement. We also study the total absorption cross section and demonstrate that, as in the nonrotating case, it hasmore » a different behavior for fermions and gauge bosons in the low-energy limit, while it follows a universal behavior - reaching a constant, spin-independent, asymptotic value - in the high-energy regime.« less
  • Black holes do not Hawking-radiate strictly blackbody radiation due to well-known frequency-dependent greybody factors. These factors arise from frequency-dependent potential barriers outside the horizon which filter the initially blackbody spectrum emanating from the horizon. D-brane bound states, in a thermally excited state corresponding to near-extremal black holes, also do not emit blackbody radiation: The bound state radiation spectrum encodes the energy spectrum of its excitations. We study a near-extremal five-dimensional black hole. We show that in a wide variety of circumstances including both neutral and charged emission, the effect of the greybody filter is to transform the blackbody radiation spectrummore » precisely into the bound state radiation spectrum. Implications of this result for the information puzzle in the context of near-extremal black hole dynamics are discussed. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We study the emission of scalar fields into the bulk from a six-dimensional rotating black hole pierced by a 3-brane. We determine the angular eigenvalues in the presence of finite brane tension by using the continued fraction method. The radial equation is integrated numerically, giving the absorption probability (graybody factor) in a wider frequency range than in the preexisting literature. We then compute the power and angular momentum emission spectra for different values of the rotation parameter and brane tension, and compare their relative behavior in detail. As is expected from the earlier result for a nonrotating black hole, themore » finite brane tension suppresses the emission rates. As the rotation parameter increases, the power spectra are reduced at low frequencies due to the smaller Hawking temperature and are enhanced at high frequencies due to superradiance. The angular momentum spectra are enhanced over the whole frequency range as the rotation parameter increases. The spectra and the amounts of energy and angular momentum radiated away into the bulk are thus determined by the interplay of these effects.« less
  • We investigate the propagation and evolution for a massless scalar field in the background of {lambda}=1/2 Horava-Lifshitz black hole with the condition of detailed balance. We fortunately obtain an exact solution for the Klein-Gordon equation. Then, we find an analytical expression for the greybody factor which is valid for any frequency and also exactly show that the perturbation decays without any oscillation. All of these can help us to understand more about the Horava-Lifshitz gravity.
  • We derive the wave equation for a minimally coupled scalar field in the background of a general rotating five-dimensional black hole. It is written in a form that involves two types of thermodynamic variables, defined at the inner and outer event horizon, respectively. We model the microscopic structure as an effective string theory, with the thermodynamic properties of the left- and right-moving excitations related to those of the horizons. Previously known solutions to the wave equation are generalized to the rotating case, and their regime of validity is sharpened. We calculate the greybody factors and interpret the resulting Hawking emissionmore » spectrum microscopically in several limits. We find a U-duality-invariant expression for the effective string length that does not assume a hierarchy between the charges. It accounts for the universal low-energy absorption cross section in the general nonextremal case. {copyright} {ital 1997} {ital The American Physical Society}« less