65 research outputs found
Bergmann-Thomson energy-momentum complex for solutions more general than the Kerr-Schild class
In a very well-known paper, Virbhadra's research group proved that the
Weinberg, Papapetrou, Landau and Lifshitz, and Einstein energy-momentum
complexes ``coincide'' for all metrics of Kerr-Schild class. A few years later,
Virbhadra clarified that this ``coincidence'' in fact holds for metrics more
general than the Kerr-Schild class. In the present paper, this study is
extended for the Bergmann-Thomson complex and it is proved that this complex
also ``coincides'' with those complexes for a more general than the Kerr-Schild
class metric.Comment: RevTex, 12 page
Energy and Momentum densities of cosmological models, with equation of state , in general relativity and teleparallel gravity
We calculated the energy and momentum densities of stiff fluid solutions,
using Einstein, Bergmann-Thomson and Landau-Lifshitz energy-momentum complexes,
in both general relativity and teleparallel gravity. In our analysis we get
different results comparing the aforementioned complexes with each other when
calculated in the same gravitational theory, either this is in general
relativity and teleparallel gravity. However, interestingly enough, each
complex's value is the same either in general relativity or teleparallel
gravity. Our results sustain that (i) general relativity or teleparallel
gravity are equivalent theories (ii) different energy-momentum complexes do not
provide the same energy and momentum densities neither in general relativity
nor in teleparallel gravity. In the context of the theory of teleparallel
gravity, the vector and axial-vector parts of the torsion are obtained. We show
that the axial-vector torsion vanishes for the space-time under study.Comment: 15 pages, no figures, Minor typos corrected; version to appear in
International Journal of Theoretical Physic
Hawking Radiation from Non-Extremal D1-D5 Black Hole via Anomalies
We take the method of anomaly cancellation for the derivation of Hawking
radiation initiated by Robinson and Wilczek, and apply it to the non-extremal
five-dimensional D1-D5 black hole in string theory. The fluxes of the electric
charge flow and the energy-momentum tensor from the black hole are obtained.
They are shown to match exactly with those of the two-dimensional black body
radiation at the Hawking temperature.Comment: 14 page
The Energy-Momentum Tensor in the 1+1 dimensional non-rotating BTZ black hole
We study the energy-momentum tensor for the real scalar field on the 1+1
dimensional BTZ black hole. We obtain closed expressions for it.Comment: 7 pages. Accepted for publication in General Relativity and
Gravitation, 201
Bogoliubov Coefficients of 2D Charged Black Holes
We exactly calculate the thermal distribution and temperature of Hawking
radiation for a two-dimensional charged dilatonic black hole after it has
settled down to an "equilibrium" state. The calculation is carried out using
the Bogoliubov coefficients. The background of the process is furnished by a
preexisting black hole and not by collapsing matter as considered by Giddings
and Nelson for the case of a Schwarzschild black hole. Furthermore, the
vanishing of the temperature and/or the Hawking radiation in the extremal case
is obtained as a regular limit of the general case.Comment: 9 pages, 1 eps figur
On the energy of charged black holes in generalized dilaton-axion gravity
In this paper we calculate the energy distribution of some charged black
holes in generalized dilaton-axion gravity. The solutions correspond to charged
black holes arising in a Kalb-Ramond-dilaton background and some existing
non-rotating black hole solutions are recovered in special cases. We focus our
study to asymptotically flat and asymptotically non-flat types of solutions and
resort for this purpose to the M{\o}ller prescription. Various aspects of
energy are also analyzed.Comment: LaTe
Energy and Momentum Distributions of Kantowski and Sachs Space-time
We use the Einstein, Bergmann-Thomson, Landau-Lifshitz and Papapetrou
energy-momentum complexes to calculate the energy and momentum distributions of
Kantowski and Sachs space-time. We show that the Einstein and Bergmann-Thomson
definitions furnish a consistent result for the energy distribution, but the
definition of Landau-Lifshitz do not agree with them. We show that a signature
switch should affect about everything including energy distribution in the case
of Einstein and Papapetrou prescriptions but not in Bergmann-Thomson and
Landau-Lifshitz prescriptions.Comment: 12 page
Are Extremal 2D Black Holes Really Frozen ?
In the standard methodology for evaluating the Hawking radiation emanating
from a black hole, the background geometry is fixed. Trying to be more
realistic we consider a dynamical geometry for a two-dimensional charged black
hole and we evaluate the Hawking radiation as tunneling process. This
modification to the geometry gives rise to a nonthermal part in the radiation
spectrum. We explore the consequences of this new term for the extremal case.Comment: 7 pages, LaTeX, no figure
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
The Energy of Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics
According to the Einstein, Weinberg, and M{\o}ller energy-momentum complexes,
we evaluate the energy distribution of the singularity-free solution of the
Einstein field equations coupled to a suitable nonlinear electrodynamics
suggested by Ay\'{o}n-Beato and Garc\'{i}a. The results show that the energy
associated with the definitions of Einstein and Weinberg are the same, but
M{\o}ller not. Using the power series expansion, we find out that the first two
terms in the expression are the same as the energy distributions of the
Reissner-Nordstr\"{o}m solution, and the third term could be used to survey the
factualness between numerous solutions of the Einstein field eqautions coupled
to a nonlinear electrodynamics.Comment: 11 page
- …