240 research outputs found
Particle-like solutions to higher order curvature Einstein--Yang-Mills systems in d dimensions
We consider the superposition of the first two members of the gravitational
hierarchy (Einstein plus first Gauss-Bonnet(GB)) interacting with the
superposition of the first two members of the Yang--Mills
hierarchy, in dimensions. Such systems can occur in the low energy
effective action of string theory. Particle-like solutions %for the systems
with only an Einstein term, and with only a GB term, in dimensions are
constructed respectively. Our results reveal qualitatively new properties
featuring double-valued solutions with critical behaviour. In this preliminary
study, we have restricted ourselves to one-node solutions.Comment: 10 pages, 11 figure
Gravitating sphalerons and sphaleron black holes in asymptotically anti-de Sitter spacetime
Numerical arguments are presented for the existence of spherically symmetric
regular and black hole solutions of the EYMH equations with a negative
cosmological constant. These solutions approach asymptotically the anti-de
Sitter spacetime. The main properties of the solutions and the differences with
respect to the asymptotically flat case are discussed. The instability of the
gravitating sphaleron solutions is also proven.Comment: 30 pages, LaTeX, 8 Encapsulated PostScript figure
Dyons in N=4 Gauged Supergravity
We study monopole and dyon solutions to the equations of motion of the
bosonic sector of N = 4 gauged supergravity in four dimensional space-time. A
static, spherically symmetric ansatz for the metric, gauge fields, dilaton and
axion leads to soliton solutions which, in the electrically charged case, have
compact spatial sections. Both analytical and numerical results for the
solutions are presented.Comment: 12 pages, 7 figures. Minor changes, references adde
Kinetic equilibration in heavy ion collisions: the role of elastic processes
We discuss the question of thermalization during the very early stages of a
high energy heavy ion collision. We review a recent study where we explicitely
showed that, contrarily to a widely used assumption, elastic collisions between
the produced partons are not sufficient to rapidly drive the system toward
local kinetic equilibrium. We then briefly discuss recent developments
concerning the description of kinetic equilibration and comment on some open
issues related to phenomenology.Comment: Talk given at "Quark Matter 2002", July 17-24, Nantes, Franc
Magnetic charge, angular momentum and negative cosmological constant
We argue that there are no axially symmetric rotating monopole solutions for
a Yang-Mills-Higgs theory in flat spacetime background. We construct axially
symmetric Yang-Mills-Higgs solutions in the presence of a negative cosmological
constant, carrying magnetic charge and a nonvanishing electric charge.
However, these solution are also nonrotating.Comment: 17 pages, LaTeX, 7 figure
Monopoles, Dyons and Black Holes in the Four-Dimensional Einstein-Yang-Mills Theory
A continuum of monopole, dyon and black hole solutions exist in the
Einstein-Yang-Mills theory in asymptotically anti-de Sitter space. Their
structure is studied in detail. The solutions are classified by non-Abelian
electric and magnetic charges and the ADM mass. The stability of the solutions
which have no node in non-Abelian magnetic fields is established. There exist
critical spacetime solutions which terminate at a finite radius, and have
universal behavior. The moduli space of the solutions exhibits a fractal
structure as the cosmological constant approaches zero.Comment: 36 Pages, 16 Figures. Minor typos corrected and one figure modifie
Perturbations of global monopoles as a black hole's hair
We study the stability of a spherically symmetric black hole with a global
monopole hair. Asymptotically the spacetime is flat but has a deficit solid
angle which depends on the vacuum expectation value of the scalar field. When
the vacuum expectation value is larger than a certain critical value, this
spacetime has a cosmological event horizon. We investigate the stability of
these solutions against the spherical and polar perturbations and confirm that
the global monopole hair is stable in both cases. Although we consider some
particular modes in the polar case, our analysis suggests the conservation of
the "topological charge" in the presence of the event horizons and violation of
black hole no-hair conjecture in asymptotically non-flat spacetime.Comment: 11 pages, 2 figures, some descriptions were improve
Topological black holes in su(N) Einstein-Yang-Mills theory with a negative cosmological constant
We investigate the phase space of topological black hole solutions of su(N) Einstein-Yang-Mills theory in anti-de Sitter space with a purely magnetic gauge potential. The gauge field is described by Nâ1 magnetic gauge field functions Ï_j, j=1,âŠ,Nâ1. For su(2) gauge group, the function Ï1 has no zeros. This is no longer the case when we consider a larger gauge group. The phase space of topological black holes is considerably simpler than for the corresponding spherically symmetric black holes, but for N>2 and a flat event horizon, there exist solutions where at least one of the Ïj functions has one or more zeros. For most of the solutions, all the Ïj functions have no zeros, and at least some of these are linearly stable
Gravitating Instantons In 3 Dimensions
We study the Einstein-Chern-Simons gravity coupled to Yang-Mills-Higgs theory
in three dimensional Euclidean space with cosmological constant. The classical
equations reduce to Bogomol'nyi type first order equations in curved space.
There are BPS type gauge theory instanton (monopole) solutions of finite action
in a gravitational instanton which itself has a finite action. We also discuss
gauge theory instantons in the vacuum (zero action) AdS space. In addition we
point out to some exact solutions which are singular.Comment: 17 pages, 4 figures, title has changed, gravitational instanton
actions are adde
Stable monopole and dyon solutions in the Einstein-Yang-Mills theory in asymptotically anti-de Sitter Space
A continuum of new monopole and dyon solutions in the Einstein-Yang-Mills
theory in asymptotically anti-de Sitter space are found. They are regular
everywhere and specified with their mass, and non-Abelian electric and magnetic
charges. A class of monopole solutions which have no node in non-Abelian
magnetic fields are shown to be stable against spherically symmetric linear
perturbations.Comment: 9 pages with 5 figures. Revised version. To appear in Phys Rev Let
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