134 research outputs found
On the semiclassical treatment of Hawking radiation
In the context of the semiclassical treatment of Hawking radiation we prove
the universality of the reduced canonical momentum for the system of a massive
shell self gravitating in a spherical gravitational field within the Painlev\'e
family of gauges. We show that one can construct modes which are regular on the
horizon both by considering as hamiltonian the exterior boundary term and by
using as hamiltonian the interior boundary term. The late time expansion is
given in both approaches and their time Fourier expansion computed to reproduce
the self reaction correction to the Hawking spectrum.Comment: 18 pages, LaTeX, Corrected typo
Hawking Radiation as Tunneling: the D-dimensional rotating case
The tunneling method for the Hawking radiation is revisited and applied to
the dimensional rotating case. Emphasis is given to covariance of results.
Certain ambiguities afflicting the procedure are resolved.Comment: Talk delivered at the Seventh International Workshop Quantum Field
Theory under the influence of External Conditions, QFEXT'05, september
05,Barcelona, Spain. To appear in Journal of Phys.
Thermodynamical properties of hairy black holes in n spacetimes dimensions
The issue concerning the existence of exact black hole solutions in presence
of non vanishing cosmological constant and scalar fields is reconsidered. With
regard to this, in investigating no-hair theorem violations, exact solutions of
gravity having as a source an interacting and conformally coupled scalar field
are revisited in arbitrary dimensional non asymptotically flat space-times. New
and known hairy black hole solutions are discussed. The thermodynamical
properties associated with these solutions are investigated and the invariance
of the black hole entropy with respect to different conformal frames is proven.Comment: Latex document, 23 pages, references added to section [1] and [3],
typos correcte
What kinds of coordinate can keep the Hawking temperature invariant for the static spherically symmetric black hole?
By studying the Hawking radiation of the most general static spherically
symmetric black hole arising from scalar and Dirac particles tunnelling, we
find the Hawking temperature is invariant in the general coordinate
representation (\ref{arbitrary1}), which satisfies two conditions: a) its
radial coordinate transformation is regular at the event horizon; and b) there
is a time-like Killing vector.Comment: 10 page
Hawking Radiation as Quantum Tunneling in Rindler Coordinate
We substantiate the Hawking radiation as quantum tunneling of fields or
particles crossing the horizon by using the Rindler coordinate. The thermal
spectrum detected by an accelerated particle is interpreted as quantum
tunneling in the Rindler spacetime. Representing the spacetime near the horizon
locally as a Rindler spacetime, we find the emission rate by tunneling, which
is expressed as a contour integral and gives the correct Boltzmann factor. We
apply the method to non-extremal black holes such as a Schwarzschild black
hole, a non-extremal Reissner-Nordstr\"{o}m black hole, a charged Kerr black
hole, de Sitter space, and a Schwarzschild-anti de Sitter black hole.Comment: LaTex 19 pages, no figure; references added and replaced by the
version accepted in JHE
On the Hawking radiation as tunneling for a class of dynamical black holes
The instability against emission of massless particles by the trapping
horizon of an evolving black hole is analyzed with the use of the
Hamilton-Jacobi method. The method automatically selects one special expression
for the surface gravity of a changing horizon. Indeed, the strength of the
horizon singularity turns out to be governed by the surface gravity as was
defined a decade ago by Hayward using Kodama's theory of spherically symmetric
gravitational fields. The theory also applies to point masses embedded in an
expanding universe, were the surface gravity is still related to Kodama-Hayward
theory. As a bonus of the tunneling method, we gain the insight that the
surface gravity still defines a temperature parameter as long as the evolution
is sufficiently slow that the black hole pass through a sequence of
quasi-equilibrium states.Comment: added references for section 1, corrected typos, some improvement in
notatio
Problems with Tunneling of Thin Shells from Black Holes
It is shown that is not invariant under canonical
transformations in general. Specifically for shells tunneling out of black
holes, this quantity is not invariant under canonical transformations. It can
be interpreted as the transmission coefficient only in the cases in which it is
invariant under canonical transformations. Although such cases include alpha
decay, they do not include the tunneling of shells from black holes. The
simplest extension to this formula which is invariant under canonical
transformations is proposed. However it is shown that this gives half the
correct temperature for black holes.Comment: 25 pages, 3 figures; v4: Made changes for publicatio
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