35 research outputs found
The topology of asymptotically Euclidean static perfect fluid space-time
In this thesis we prove that a (geodesically) complete, asymptotically
Euclidean, static perfect fluid space-time with connected fluid reglon and
satisfying the time-like convergence condition lS diffeomorphic to R³ x R .
It is believed that such a space-time would be spherically symmetric at
least for physically reasonable conditions on the density function p and
the pressure function p
(In)finiteness of Spherically Symmetric Static Perfect Fluids
This work is concerned with the finiteness problem for static, spherically
symmetric perfect fluids in both Newtonian Gravity and General Relativity. We
derive criteria on the barotropic equation of state guaranteeing that the
corresponding perfect fluid solutions possess finite/infinite extent. In the
Newtonian case, for the large class of monotonic equations of state, and in
General Relativity we improve earlier results
Laws Governing Isolated Horizons: Inclusion of Dilaton Couplings
Mechanics of non-rotating black holes was recently generalized by replacing
the static event horizons used in standard treatments with `isolated horizons.'
This framework is extended to incorporate dilaton couplings. Since there can be
gravitational and matter radiation outside isolated horizons, now the
fundamental parameters of the horizon, used in mechanics, must be defined using
only the local structure of the horizon, without reference to infinity. This
task is accomplished and the zeroth and first laws are established. To
complement the previous work, the entire discussion is formulated tensorially,
without any reference to spinors.Comment: Some typos corrected, references updated. Some minor clarifications
added. 20 pages, 1 figure, Revtex fil
Uniqueness Theorem for Static Black Hole Solutions of sigma-models in Higher Dimensions
We prove the uniqueness theorem for self-gravitating non-linear sigma-models
in higher dimensional spacetime. Applying the positive mass theorem we show
that Schwarzschild-Tagherlini spacetime is the only maximally extended, static
asymptotically flat solution with non-rotating regular event horizon with a
constant mapping.Comment: 5 peges, Revtex, to be published in Class.Quantum Gra
Uniqueness theorems for static spacetimes containing marginally outer trapped surfaces
Marginally outer trapped surfaces are widely considered as the best
quasi-local replacements for event horizons of black holes in General
Relativity. However, this equivalence is far from being proved, even in
stationary and static situations. In this paper we study an important aspect of
this equivalence, namely whether classic uniqueness theorems of static black
holes can be extended to static spacetimes containing weakly outer trapped
surfaces or not. Our main theorem states that, under reasonable hypotheses, a
static spacetime satisfying the null energy condition and containing an
asymptotically flat initial data set, possibly with boundary, which possesses a
bounding weakly outer trapped surface is a unique spacetime. A related result
to this theorem was given in arXiv:0711.1299, where we proved that no bounding
weakly outer trapped surface can penetrate into the exterior region of the
initial data where the static Killing vector is timelike. In this paper, we
also fill some gaps in arXiv:0711.1299 and extend this confinement result to
initial data sets with boundary.Comment: 30 pages, 9 figure
Stability in Designer Gravity
We study the stability of designer gravity theories, in which one considers
gravity coupled to a tachyonic scalar with anti-de Sitter boundary conditions
defined by a smooth function W. We construct Hamiltonian generators of the
asymptotic symmetries using the covariant phase space method of Wald et al.and
find they differ from the spinor charges except when W=0. The positivity of the
spinor charge is used to establish a lower bound on the conserved energy of any
solution that satisfies boundary conditions for which has a global minimum.
A large class of designer gravity theories therefore have a stable ground
state, which the AdS/CFT correspondence indicates should be the lowest energy
soliton. We make progress towards proving this, by showing that minimum energy
solutions are static. The generalization of our results to designer gravity
theories in higher dimensions involving several tachyonic scalars is discussed.Comment: 29 page
Uniqueness of (dilatonic) charged black holes and black p-branes in higher dimensions
We prove the uniqueness of higher dimensional (dilatonic) charged black holes
in static and asymptotically flat spacetimes for arbitrary vector-dilaton
coupling constant. An application to the uniqueness of a wide class of black
p-branes is also given.Comment: 6 page
Uniqueness Theorem of Static Degenerate and Non-degenerate Charged Black Holes in Higher Dimensions
We prove the uniqueness theorem for static higher dimensional charged black
holes spacetime containing an asymptotically flat spacelike hypersurface with
compact interior and with both degenerate and non-degenerate components of the
event horizon.Comment: 9 pages, RevTex, to be published in Phys.Rev.D1