598 research outputs found
The 2+1 charged black hole in topologically massive Electrodynamics
The 2+1 black hole coupled to a Maxwell field can be charged in two different
ways. On the one hand, it can support a Coulomb field whose potential grows
logarithmically in the radial coordinate. On the other, due to the existence of
a non-contractible cycle, it also supports a topological charge whose value is
given by the corresponding Abelian holonomy. Only the Coulomb charge, however,
is given by a constant flux integral with an associated continuity equation.
The topological charge does not gravitate and is somehow decoupled from the
black hole. This situation changes abruptly if one turns on the Chern-Simons
term for the Maxwell field. First, the flux integral at infinity becomes equal
to the topological charge. Second, demanding regularity of the black hole
horizon, it is found that the Coulomb charge (whose associated potential now
decays by a power law) must vanish identically. Hence, in 2+1 topologically
massive electrodynamics coupled to gravity, the black hole can only support
holonomies for the Maxwell field. This means that the charged black hole, as
the uncharged one, is constructed from the vacuum by means of spacetime
identifications.Comment: 4 pages, no figures, LaTex, added reference
Black Rings, Boosted Strings and Gregory-Laflamme
We investigate the Gregory-Laflamme instability for black strings carrying
KK-momentum along the internal direction. We demonstrate a simple kinematical
relation between the thresholds of the classical instability for the boosted
and static black strings. We also find that Sorkin's critical dimension depends
on the internal velocity and in fact disappears for sufficiently large boosts.
Our analysis implies the existence of an analogous instability for the
five-dimensional black ring of Emparan and Reall. We also use our results for
boosted black strings to construct a simple model of the black ring and argue
that such rings exist in any number of space-time dimensions.Comment: 26 pages, 6 figure
A no-go on strictly stationary spacetimes in four/higher dimensions
We show that strictly stationary spacetimes cannot have non-trivial
configurations of form fields/complex scalar fields and then the spacetime
should be exactly Minkowski or anti-deSitter spacetimes depending on the
presence of negative cosmological constant. That is, self-gravitating complex
scalar fields and form fields cannot exist.Comment: 8 page
Stationary perturbations and infinitesimal rotations of static Einstein-Yang-Mills configurations with bosonic matter
Using the Kaluza-Klein structure of stationary spacetimes, a framework for
analyzing stationary perturbations of static Einstein-Yang-Mills configurations
with bosonic matter fields is presented. It is shown that the perturbations
giving rise to non-vanishing ADM angular momentum are governed by a
self-adjoint system of equations for a set of gauge invariant scalar
amplitudes. The method is illustrated for SU(2) gauge fields, coupled to a
Higgs doublet or a Higgs triplet. It is argued that slowly rotating black holes
arise generically in self-gravitating non-Abelian gauge theories with bosonic
matter, whereas, in general, soliton solutions do not have rotating
counterparts.Comment: 8 pages, revtex, no figure
Pulsation of Spherically Symmetric Systems in General Relativity
The pulsation equations for spherically symmetric black hole and soliton
solutions are brought into a standard form. The formulae apply to a large class
of field theoretical matter models and can easily be worked out for specific
examples. The close relation to the energy principle in terms of the second
variation of the Schwarzschild mass is also established. The use of the general
expressions is illustrated for the Einstein-Yang-Mills and the Einstein-Skyrme
system.Comment: 21 pages, latex, no figure
A Mass Bound for Spherically Symmetric Black Hole Spacetimes
Requiring that the matter fields are subject to the dominant energy
condition, we establish the lower bound for the
total mass of a static, spherically symmetric black hole spacetime. ( and denote the area and the surface gravity of the horizon,
respectively.) Together with the fact that the Komar integral provides a simple
relation between and the strong energy condition,
this enables us to prove that the Schwarzschild metric represents the only
static, spherically symmetric black hole solution of a selfgravitating matter
model satisfying the dominant, but violating the strong energy condition for
the timelike Killing field at every point, that is, .
Applying this result to scalar fields, we recover the fact that the only black
hole configuration of the spherically symmetric Einstein-Higgs model with
arbitrary non-negative potential is the Schwarzschild spacetime with constant
Higgs field. In the presence of electromagnetic fields, we also derive a
stronger bound for the total mass, involving the electromagnetic potentials and
charges. Again, this estimate provides a simple tool to prove a ``no-hair''
theorem for matter fields violating the strong energy condition.Comment: 16 pages, LATEX, no figure
Beyond the Heisenberg time: Semiclassical treatment of spectral correlations in chaotic systems with spin 1/2
The two-point correlation function of chaotic systems with spin 1/2 is
evaluated using periodic orbits. The spectral form factor for all times thus
becomes accessible. Equivalence with the predictions of random matrix theory
for the Gaussian symplectic ensemble is demonstrated. A duality between the
underlying generating functions of the orthogonal and symplectic symmetry
classes is semiclassically established
A classification (uniqueness) theorem for rotating black holes in 4D Einstein-Maxwell-dilaton theory
In the present paper we prove a classification (uniqueness) theorem for
stationary, asymptotically flat black hole spacetimes with connected and
non-degenerate horizon in 4D Einstein-Maxwell-dilaton theory with an arbitrary
dilaton coupling parameter . We show that such black holes are uniquely
specified by the length of the horizon interval, angular momentum, electric and
magnetic charge and the value of the dilaton field at infinity when the dilaton
coupling parameter satisfies . The proof is based on the
nonpositivity of the Riemann curvature operator on the space of the potentials.
A generalization of the classification theorem for spacetimes with disconnected
horizons is also given.Comment: 15 pages, v2 typos correcte
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