Bulk and brane decay of a (4+n)-dimensional Schwarzschild de Sitter black hole: Scalar radiation (original) (raw)
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Physical review, 2016
In this work, we study the propagation of scalar fields in the gravitational background of a higher-dimensional Schwarzschild-de-Sitter black hole as well as on the projected-on-thebrane 4-dimensional background. The scalar fields have also a non-minimal coupling to the corresponding, bulk or brane, scalar curvature. We perform a comprehensive study by deriving exact numerical results for the greybody factors, and study their profile in terms of particle and spacetime properties. We then proceed to derive the Hawking radiation spectra for a higher-dimensional Schwarzschild-de-Sitter black hole, and we study both bulk and brane channels. We demonstrate that the non-minimal field coupling, that creates an effective mass term for the fields, suppresses the energy emission rates while the cosmological constant assumes a dual role. By computing the relative energy rates and the total emissivity ratio for bulk and brane emission, we demonstrate that the combined effect of a large number of extra dimensions and value of the field coupling gives to the bulk channel the clear domination in the bulk-brane energy balance.
Hawking radiation from a (4+n)-dimensional black hole: exact results for the Schwarzschild phase
Journal of High Energy Physics, 2003
We start our analysis by deriving a master equation that describes the motion of a field with arbitrary spin s on a 3-brane embedded in a non-rotating, uncharged (4 + n)-dimensional black hole background. By numerical analysis, we derive exact results for the greybody factors and emission rates for scalars, fermions and gauge bosons emitted directly on the brane, for all energy regimes and for an arbitrary number n of extra dimensions. The relative emissivities on the brane for different types of particles are computed and their dependence on the dimensionality of spacetime is demonstrated -we therefore conclude that both the amount and the type of radiation emitted can be used for the determination of n if the Hawking radiation from these black holes is observed. The emission of scalar modes in the bulk from the same black holes is also studied and the relative bulk-to-brane energy emissivity is accurately computed. We demonstrate that this quantity varies considerably with n but always remains smaller than unity -this provides firm support to earlier arguments made by Emparan, Horowitz and Myers.
Physical Review D, 2014
In this work, we consider the propagation of scalar particles in a higher-dimensional Schwarzschild-de-Sitter black-hole spacetime, both on the brane and in the bulk. Our analysis applies for arbitrary partial modes and for both minimal and non-minimal coupling of the scalar field. A general expression for the greybody factor is analytically derived in each case, and its low-energy behaviour is studied in detail. Its profile in terms of scalar properties (angular-momentum number and non-minimal coupling parameter) and spacetime properties (number of extra dimensions and cosmological constant) is thoroughly investigated. In contrast to previous studies, the effect of the cosmological constant is taken into account both close to and far away from the black-hole horizon. The dual role of the cosmological constant, that may act either as a helping agent to the emission of scalar particles or as a deterring effect depending on the value of the non-minimal coupling parameter, is also demonstrated.
Black Hole Particle Emission in Higher-Dimensional Spacetimes
Physical Review Letters, 2006
In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption crosssections, the relative emissivities and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in models with extra dimensions and black hole detection in particle colliders.
Footprints of Higher-Dimensional Decaying Black Holes
2012
We review the current results for the emission of Hawking radiation by a higherdimensional black hole during the Schwarzschild and the spin-down phases. We discuss particularly the role of the angular variation of the emitted radiation on the brane during the latter phase, the radiation spectra for gravitons in the bulk, and the effect of the mass of the emitted particles in determining the bulk-to-brane energy balance.
Physical Review D
The absence of a true thermodynamical equilibrium for an observer located in the causal area of a Schwarzschild-de Sitter spacetime has repeatedly raised the question of the correct definition of its temperature. In this work, we consider five different temperatures for a higher-dimensional Schwarzschild-de Sitter black hole: the bare T 0 , the normalised T BH and three effective ones given in terms of both the black hole and cosmological horizon temperatures. We find that these five temperatures exhibit similarities but also significant differences in their behaviour as the number of extra dimensions and the value of the cosmological constant are varied. We then investigate their effect on the energy emission spectra of Hawking radiation. We demonstrate that the radiation spectra for the normalised temperature T BH-proposed by Bousso and Hawking over twenty years ago-leads to the dominant emission curve while the other temperatures either support a significant emission rate only at a specific Λ regime or they have their emission rates globally suppressed. Finally, we compute the bulk-over-brane emissivity ratio and show that the use of different temperatures may lead to different conclusions regarding the brane or bulk dominance.
Reading the Number of Extra Dimensions in the Spectrum of Hawking Radiation
2004
After a brief review of the production and decay of Schwarzschild-like (4 + n)dimensional black holes in the framework of theories with Large Extra Dimensions, we proceed to derive the greybody factors and emission rates for scalars, fermions and gauge bosons on the brane. We present and discuss analytic and numerical methods for obtaining the above results, and demonstrate that both the amount and type of Hawking radiation emitted by the black hole can help us to determine the number of spacelike dimensions that exist in nature.
Comparing two approaches to Hawking radiation of Schwarzschild-de Sitter black holes
Classical and Quantum Gravity, 2009
We study two different ways to analyze the Hawking evaporation of a Schwarzschild-de Sitter black hole. The first one uses the standard approach of surface gravity evaluated at the possible horizons. The second method derives its results via the Generalized Uncertainty Principle (GUP) which offers a yet different method to look at the problem. In the case of a Schwarzschild black hole it is known that this methods affirms the existence of a black hole remnant (minimal mass M min ) of the order of Planck mass m pl and a corresponding maximal temperature T max also of the order of m pl . The standard T (M ) dispersion relation is, in the GUP formulation, deformed in the vicinity of Planck length l pl which is the smallest value the horizon can take. We generalize the uncertainty principle to Schwarzschild-de Sitter spacetime with the cosmological constant Λ = 1/m 2 Λ and find a dual relation which, compared to M min and T max , affirms the existence of a maximal mass M max of the order (m pl /m Λ )m pl , minimum temperature T min ∼ m Λ . As compared to the standard approach we find a deformed dispersion relation T (M ) close to l pl and in addition at the maximally possible horizon approximately at r Λ = 1/m Λ . T (M ) agrees with the standard results at l pl ≪ r ≪ r Λ (or equivalently at M min ≪ M ≪ M max ).
Black Holes in Theories with Large Extra Dimensions
International Journal of Modern Physics A, 2004
We start by reviewing the existing literature on the creation of black holes during high-energy particle collisions, both in the absence and in the presence of extra, compact, spacelike dimensions. Then, we discuss in detail the properties of the produced higher-dimensional black holes, namely the horizon radius, temperature and life-time, as well as the physics that governs the evaporation of these objects, through the emission of Hawking radiation. We first study the emission of visible Hawking radiation on the brane: we derive a master equation for the propagation of fields with arbitrary spin in the induced-on-the-brane black hole background, and we review all existing results in the literature for the emission of scalars, fermions and gauge bosons during the spin-down and Schwarzschild phases of the life of the black hole. Both analytical and numerical results for the greybody factors and radiation spectra are reviewed and exact results for the number and type of fields emitted on the brane as a function of the dimensionality of spacetime are discussed. We finally study the emission of Hawking radiation in the bulk: greybody factors and radiation spectra are presented for the emission of scalar modes, and the ratio of the missing energy over the visible one is calculated for different values of the number of extra dimensions.
Greybody factor for an electrically charged regular-de Sitter black holes in ddd-dimensions
2021
In this article, we study the propagation of scalar fields in the gravitational background of a spherically symmetric, electrically charged, regular-de Sitter black holes in higher dimensions. We carry out a thorough investigation of the grey body factors, by deriving analytical expressions for both minimally and non-minimally coupled scalar fields. Then we study the profile of grey body factors in terms of particle properties, namely the angular momentum quantum number and the non-minimal coupling constant, and the spacetime properties, namely the dimension, the cosmological constant and the non-linear charge parameter. We then derive the Hawking radiation spectra for a higher-dimensional electrically charged regular-de Sitter black hole. We find that the non-minimal coupling may suppress the greybody factor and the non-linear charge parameter may enhance it, but they both suppress the energy emission rate of Hawking radiation.