11,900 research outputs found
Non-Abelian Black Holes in D=5 Maximal Gauged Supergravity
We investigate static non-abelian black hole solutions of anti-de Sitter
Einstein-Yang-Mills-Dilaton gravity, which is obtained as a consistent
truncation of five-dimensional maximal gauged supergravity. If the dilaton is
(consistently) set to zero, the remaining equations of motion, with a
spherically-symmetric ansatz, may be derived from a superpotential. The
associated first-order equations admit an explicit solution supported by a
non-abelian SU(2) gauge potential, which has a logarithmically growing mass
term. In an extremal limit the horizon geometry becomes AdS. If
the dilaton is also excited, the equations of motion cannot easily be solved
explicitly, but we obtain the asymptotic form of the more general non-abelian
black holes in this case. An alternative consistent truncation, in which the
Yang-Mills fields are set to zero, also admits a description in terms of a
superpotential. This allows us to construct explicit wormhole solutions
(neutral spherically-symmetric domain walls). These solutions may be
generalised to dimensions other than five.Comment: Author's address, and a reference, adde
Domain Walls and Massive Gauged Supergravity Potentials
We point out that massive gauged supergravity potentials, for example those
arising due to the massive breathing mode of sphere reductions in M-theory or
string theory, allow for supersymmetric (static) domain wall solutions which
are a hybrid of a Randall-Sundrum domain wall on one side, and a dilatonic
domain wall with a run-away dilaton on the other side. On the anti-de Sitter
(AdS) side, these walls have a repulsive gravity with an asymptotic region
corresponding to the Cauchy horizon, while on the other side the runaway
dilaton approaches the weak coupling regime and a non-singular attractive
gravity, with the asymptotic region corresponding to the boundary of spacetime.
We contrast these results with the situation for gauged supergravity potentials
for massless scalar modes, whose supersymmetric AdS extrema are generically
maxima, and there the asymptotic regime transverse to the wall corresponds to
the boundary of the AdS spacetime. We also comment on the possibility that the
massive breathing mode may, in the case of fundamental domain-wall sources,
stabilize such walls via a Goldberger-Wise mechanism.Comment: latex file, 11 pages, 3 figure
Consistent Kaluza-Klein Sphere Reductions
We study the circumstances under which a Kaluza-Klein reduction on an
n-sphere, with a massless truncation that includes all the Yang-Mills fields of
SO(n+1), can be consistent at the full non-linear level. We take as the
starting point a theory comprising a p-form field strength and (possibly) a
dilaton, coupled to gravity in the higher dimension D. We show that aside from
the previously-studied cases with (D,p)=(11,4) and (10,5) (associated with the
S^4 and S^7 reductions of D=11 supergravity, and the S^5 reduction of type IIB
supergravity), the only other possibilities that allow consistent reductions
are for p=2, reduced on S^2, and for p=3, reduced on S^3 or S^{D-3}. We
construct the fully non-linear Kaluza-Klein Ansatze in all these cases. In
particular, we obtain D=3, N=8, SO(8) and D=7, N=2, SO(4) gauged supergravities
from S^7 and S^3 reductions of N=1 supergravity in D=10.Comment: 27 pages, Latex, typo correcte
Entropy-Product Rules for Charged Rotating Black Holes
We study the universal nature of the product of the entropies of all horizons
of charged rotating black holes. We argue, by examining further explicit
examples, that when the maximum number of rotations and/or charges are turned
on, the entropy product is expressed in terms of angular momentum and/or
charges only, which are quantized. (In the case of gauged supergravities, the
entropy product depends on the gauge-coupling constant also.) In two-derivative
gravities, the notion of the "maximum number" of charges can be defined as
being sufficiently many non-zero charges that the Reissner-Nordstrom black hole
arises under an appropriate specialisation of the charges. (The definition can
be relaxed somewhat in charged AdS black holes in .) In
higher-derivative gravity, we use the charged rotating black hole in
Weyl-Maxwell gravity as an example for which the entropy product is still
quantized, but it is expressed in terms of the angular momentum only, with no
dependence on the charge. This suggests that the notion of maximum charges in
higher-derivative gravities requires further understanding.Comment: References added. 24 page
Decoupling Limit, Lens Spaces and Taub-NUT: D=4 Black Hole Microscopics from D=5 Black Holes
We study the space-times of non-extremal intersecting p-brane configurations
in M-theory, where one of the components in the intersection is a ``NUT,'' i.e.
a configuration of the Taub-NUT type. Such a Taub-NUT configuration
corresponds, upon compactification to D=4, to a Gross-Perry-Sorkin (GPS)
monopole. We show that in the decoupling limit of the CFT/AdS correspondence,
the 4-dimensional transverse space of the NUT configuration in D=5 is foliated
by surfaces that are cyclic lens spaces S^3/Z_N, where N is the quantised
monopole charge. By contrast, in D=4 the 3-dimensional transverse space of the
GPS monopole is foliated by 2-spheres. This observation provides a
straightforward interpretation of the microscopics of a D=4 string-theory black
hole, with a GPS monopole as one of its constituents, in terms of the
corresponding D=5 black hole with no monopole. Using the fact that the
near-horizon region of the NUT solution is a lens space, we show that if the
effect of the Kaluza-Klein massive modes is neglected, p-brane configurations
can be obtained from flat space-time by means of a sequence of dimensional
reductions and oxidations, and U-duality transformations.Comment: 22 pages, Late
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Interacting Intersections
Intersecting p-branes can be viewed as higher-dimensional interpretations of
multi-charge extremal p-branes, where some of the individual p-branes undergo
diagonal dimensional oxidation, while the others oxidise vertically. Although
the naive vertical oxidation of a single p-brane gives a continuum of p-branes,
a more natural description arises if one considers a periodic array of p-branes
in the higher dimension, implying a dependence on the compactification
coordinates. This still reduces to the single lower-dimensional p-brane when
viewed at distances large compared with the period. Applying the same logic to
the multi-charge solutions, we are led to consider more general classes of
intersecting p-brane solutions, again depending on the compactification
coordinates, which turn out to be described by interacting functions rather
than independent harmonic functions. These new solutions also provide a more
satisfactory interpretation for the lower-dimensional multi-charge p-branes,
which otherwise appear to be nothing more than the improbable coincidence of
charge-centres of individual constituents with zero binding energy.Comment: 20 pages, Latex, references adde
General Kerr-NUT-AdS Metrics in All Dimensions
The Kerr-AdS metric in dimension D has cohomogeneity [D/2]; the metric
components depend on the radial coordinate r and [D/2] latitude variables \mu_i
that are subject to the constraint \sum_i \mu_i^2=1. We find a coordinate
reparameterisation in which the \mu_i variables are replaced by [D/2]-1
unconstrained coordinates y_\alpha, and having the remarkable property that the
Kerr-AdS metric becomes diagonal in the coordinate differentials dy_\alpha. The
coordinates r and y_\alpha now appear in a very symmetrical way in the metric,
leading to an immediate generalisation in which we can introduce [D/2]-1 NUT
parameters. We find that (D-5)/2 are non-trivial in odd dimensions, whilst
(D-2)/2 are non-trivial in even dimensions. This gives the most general
Kerr-NUT-AdS metric in dimensions. We find that in all dimensions D\ge4
there exist discrete symmetries that involve inverting a rotation parameter
through the AdS radius. These symmetries imply that Kerr-NUT-AdS metrics with
over-rotating parameters are equivalent to under-rotating metrics. We also
consider the BPS limit of the Kerr-NUT-AdS metrics, and thereby obtain, in odd
dimensions and after Euclideanisation, new families of Einstein-Sasaki metrics.Comment: Latex, 24 pages, minor typos correcte
A Killing tensor for higher dimensional Kerr-AdS black holes with NUT charge
In this paper, we study the recently discovered family of higher dimensional
Kerr-AdS black holes with an extra NUT-like parameter. We show that the inverse
metric is additively separable after multiplication by a simple function. This
allows us to separate the Hamilton-Jacobi equation, showing that geodesic
motion is integrable on this background. The separation of the Hamilton-Jacobi
equation is intimately linked to the existence of an irreducible Killing
tensor, which provides an extra constant of motion. We also demonstrate that
the Klein-Gordon equation for this background is separable.Comment: LaTeX, 14 pages. v2: Typo corrected and equation added. v3: Reference
added, introduction expanded, published versio
Yang-Mills-Chern-Simons Supergravity
N=(1,0) supergravity in six dimensions admits AdS_3\times S^3 as a vacuum
solution. We extend our recent results presented in hep-th/0212323, by
obtaining the complete N=4 Yang-Mills-Chern-Simons supergravity in D=3, up to
quartic fermion terms, by S^3 group manifold reduction of the six dimensional
theory. The SU(2) gauge fields have Yang-Mills kinetic terms as well as
topological Chern-Simons mass terms. There is in addition a triplet of matter
vectors. After diagonalisation, these fields describe two triplets of
topologically-massive vector fields of opposite helicities. The model also
contains six scalars, described by a GL(3,R)/SO(3) sigma model. It provides the
first example of a three-dimensional gauged supergravity that can obtained by a
consistent reduction of string-theory or M-theory and that admits AdS_3 as a
vacuum solution. There are unusual features in the reduction from
six-dimensional supergravity, owing to the self-duality condition on the 3-form
field. The structure of the full equations of motion in N=(1,0) supergravity in
D=6 is also elucidated, and the role of the self-dual field strength as torsion
is exhibited.Comment: Latex, 22 pages, hep-th number correcte
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