1,905 research outputs found

### On the Uniqueness of the Papapetrou--Majumdar Metric

We establish the equality of the ADM mass and the total electric charge for
asymptotically flat, static electrovac black hole spacetimes with completely
degenerate, not necessarily connected horizon.Comment: 9 pages, latex, no figures, to appear in Class. Quantum Gra

### 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

### 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

### Quasilocal Formalism and Black Ring Thermodynamics

The thermodynamical properties of a dipole black ring are derived using the
quasilocal formalism. We find that the dipole charge appears in the first law
in the same manner as a global charge. Using the Gibbs-Duhem relation, we also
provide a non-trivial check of the entropy/area relationship for the dipole
ring. A preliminary study of the thermodynamic stability indicates that the
neutral ring is unstable to angular fluctuations.Comment: 10 pages, no figures; v2, expanded references, misprints corrected;
v3: misprint corected in rel. (22); discussion unchange

### Instability of Einstein-Yang-Mills Solitons for Arbitrary Gauge Groups

We prove that static, spherically symmetric, asymptotically flat, regular
solutions of the Einstein-Yang-Mills equations are unstable for arbitrary gauge
groups. The proof involves the following main steps. First, we show that the
frequency spectrum of a class of radial perturbations is determined by a
coupled system of radial "Schroedinger equations". Eigenstates with negative
eigenvalues correspond to exponentially growing modes. Using the variational
principle for the ground state it is then proven that there always exist
unstable modes (at least for "generic" solitons). This conclusion is reached
without explicit knowledge of the possible equilibrium solutions.Comment: 11 pages, Latex, ZU-TH 4\9

### 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

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