179 research outputs found
Physical process version of the first law of thermodynamics for black holes in Einstein-Maxwell axion-dilaton gravity
We derive general formulae for the first order variation of the ADM mass,
angular momentum for linear perturbations of a stationary background in
Einstein-Maxwell axion-dilaton gravity being the low-energy limit of the
heterotic string theory. All these variations were expressed in terms of the
perturbed matter energy momentum tensor and the perturbed charge current
density. Combining these expressions we reached to the form of the {\it
physical version} of the first law of black hole dynamics for the stationary
black holes in the considered theory being the strong support for the cosmic
censorship.Comment: 8 pages, Revte
Thick Domain Walls in AdS Black Hole Spacetimes
Equations of motion for a real self-gravitating scalar field in the
background of a black hole with negative cosmological constant were solved
numerically. We obtain a sequence of static axisymmetric solutions representing
thick domain wall cosmological black hole systems, depending on the mass of
black hole, cosmological parameter and the parameter binding black hole mass
with the width of the domain wall. For the case of extremal cosmological black
hole the expulsion of scalar field from the black hole strongly depends on it.Comment: 20 pages, 19 figures, accepted for publication in Phys. Rev.
Superconducting Hair on Charged Black String Background
Behaviour of Dirac fermions in the background of a charged black string
penetrated by an Abelian Higgs vortex is elaborated. One finds the evidence
that the system under consideration can support fermion fields acting like a
superconducting cosmic string in the sence that a nontrivial Dirac fermion
field can be carried by the system in question. The case of nonextremal and
extremal black string vortex systems were considered. The influence of electric
and Higgs charge, the winding number and the fermion mass on the fermion
localization near the black string event horizon was studied. It turned out
that the extreme charged black string expelled fermion fields more violently
comparing to the nonextremal one.Comment: RevTex, 16 pages, 12 figures, to be published in Phys.REvD1
A Higher Dimensional Stationary Rotating Black Hole Must be Axisymmetric
A key result in the proof of black hole uniqueness in 4-dimensions is that a
stationary black hole that is ``rotating''--i.e., is such that the stationary
Killing field is not everywhere normal to the horizon--must be axisymmetric.
The proof of this result in 4-dimensions relies on the fact that the orbits of
the stationary Killing field on the horizon have the property that they must
return to the same null geodesic generator of the horizon after a certain
period, . This latter property follows, in turn, from the fact that the
cross-sections of the horizon are two-dimensional spheres. However, in
spacetimes of dimension greater than 4, it is no longer true that the orbits of
the stationary Killing field on the horizon must return to the same null
geodesic generator. In this paper, we prove that, nevertheless, a higher
dimensional stationary black hole that is rotating must be axisymmetric. No
assumptions are made concerning the topology of the horizon cross-sections
other than that they are compact. However, we assume that the horizon is
non-degenerate and, as in the 4-dimensional proof, that the spacetime is
analytic.Comment: 24 pages, no figures, v2: footnotes and references added, v3:
numerous minor revision
Decay of Dirac Massive Hair in the Background of Spherical Black Hole
The intermediate and late-time behaviour of massive Dirac hair in the static
spherically symmetric black hole spacetime was studied. It was revealed that
the intermediate asymptotic pattern of decay of massive Dirac spinor hair is
dependent on the mass of the field under consideration as well as the multiple
number of the wave mode. The long-lived oscillatory tail observed at timelike
infinity in the considered background decays slowly as t^{-5/6}.Comment: 8 pages, 5 figures, RevTex, to be published in Phys.Rev.D1
Dynamical Collapse of Charged Scalar Field in Phantom Gravity
We investigated the problem of the dynamical collapse of a self-gravitating
complex charged scalar field in Einstein-Maxwell-dilaton theory with a phantom
copuling for the adequate fields in the system under consideration. We also
considered two simplifications of it, i.e., the separate collapses of phantom
Maxwell and phantom scalar fields under the influence of Einstein gravity. One
starts with the regular spacetime and leads the evolution through the formation
of the horizons and the final singularity. We discuss the structures of
spacetimes emerging in the process of the dynamical collapse and comment on the
role of the considered fields in its course.Comment: 15 pages, RevTex, 18 figures, to be published in Phys.Rev.D1
Mechanics of multidimensional isolated horizons
Recently a multidimensional generalization of Isolated Horizon framework has
been proposed by Lewandowski and Pawlowski (gr-qc/0410146). Therein the
geometric description was easily generalized to higher dimensions and the
structure of the constraints induced by the Einstein equations was analyzed. In
particular, the geometric version of the zeroth law of the black hole
thermodynamics was proved. In this work we show how the IH mechanics can be
formulated in a dimension--independent fashion and derive the first law of BH
thermodynamics for arbitrary dimensional IH. We also propose a definition of
energy for non--rotating horizons.Comment: 25 pages, 4 figures (eps), last sections revised, acknowledgements
and a section about the gauge invariance of introduced quantities added;
typos corrected, footnote 4 on page 9 adde
Thick Domain Walls and Charged Dilaton Black Holes
We study a black hole domain wall system in dilaton gravity which is the
low-energy limit of the superstring theory. We solve numerically equations of
motion for real self-interacting scalar field and justify the existence of
static axisymmetric field configuration representing the thick domain wall in
the background of a charged dilaton black hole. It was also confirmed that the
extreme dilaton black hole always expelled the domain wall.Comment: 10 pages, 8 figures; to be published in Phys. Rev. D1
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