812 research outputs found
Effective action of (massive) IIA on manifolds with SU(3) structure
In this paper we consider compactifications of massive type IIA supergravity
on manifolds with SU(3) structure. We derive the gravitino mass matrix of the
effective four-dimensional N = 2 theory and show that vacuum expectation values
of the scalar fields naturally induce spontaneous partial supersymmetry
breaking. We go on to derive the superpotential and the Kaehler potential for
the resulting N = 1 theories. As an example we consider the SU(3) structure
manifold SU(3)/U(1)xU(1) and explicitly find N = 1 supersymmetric minima where
all the moduli are stabilised at non-trivial values without the use of
non-perturbative effects.Comment: 25 pages, 2 figures. References added and typos corrected to match
published versio
Non-Abelian black holes: The inside story
Recent progress in understanding of the internal structure of non-Abelian
black holes is discussed.
Talk given at the international Workshop on The Internal Structure of Black
Holes and Spacetime Singularities, Haifa, Israel, June 29 -- July 3, 1997.Comment: 23 pages, latex, contains 12 eps files combined in 8 figure
Monopoles and the Emergence of Black Hole Entropy
One of the remarkable features of black holes is that they possess a
thermodynamic description, even though they do not appear to be statistical
systems. We use self-gravitating magnetic monopole solutions as tools for
understanding the emergence of this description as one goes from an ordinary
spacetime to one containing a black hole. We describe how causally distinct
regions emerge as a monopole solution develops a horizon. We define an entropy
that is naturally associated with these regions and that has a clear connection
with the Hawking-Bekenstein entropy in the critical black hole limit.Comment: 6 pages, one figure RevTe
Features of gravity-Yang-Mills hierarchies in d-dimensions
Higher dimensional, direct analogues of the usual d=4 Einstein--Yang-Mills
(EYM) systems are studied. These consist of the gravitational and Yang-Mills
hierarchies in d=4p dimensional spacetimes, both consisting of 2p-form
curvature terms only. Regular and black hole solutions are constructed in
, in which dimensions the total mass-energy is finite,
generalising the familiar Bartnik-McKinnon solutions in EYM theory for p=1. In
d=4p, this similarity is complete. In the special case of d=2p+1, just beyond
the finite energy range of d, exact solutions in closed form are found.
Finally, d=2p+1 purely gravitational systems, whose solutions generalise the
static d=3 BTZ solutions, are discussed.Comment: 19 pages, 9 figure
Static Cosmological Solutions of the Einstein-Yang-Mills-Higgs Equations
Numerical evidence is presented for the existence of a new family of static,
globally regular `cosmological' solutions of the spherically symmetric
Einstein-Yang-Mills-Higgs equations. These solutions are characterized by two
natural numbers (, ), the number of nodes of the Yang-Mills
and Higgs field respectively. The corresponding spacetimes are static with
spatially compact sections with 3-sphere topology.Comment: 7 pages, 5 figures, LaTe
Static BPS 'monopoles' in all even spacetime dimensions
Two families of SO(2n) Higgs models in dimensional spacetime are
presented. One family arises from the {\it dimensional reduction} of higher
dimensional Yang-Mills systems while the construction of the other one is {\it
ad hoc}, the member of each family coinciding with the usual SU(2)
Yang-Mills--Higgs system without Higgs potential. All models support BPS
'monopole' solutions. The 'dyons' of the {\it dimensionally descended} models
are also BPS, while the electrically charged solutions of the {\it ad hoc}
models are not BPS.Comment: 15 pages, 3 figure
Gravitating BPS Monopoles in all d=4p Spacetime Dimensions
We have constructed, numerically, both regular and black hole static
solutions to the simplest possible gravitating Yang-Mills--Higgs (YMH) in
spacetime dimensions. The YMH systems consist of th power curvature fields
without a Higgs potential. The gravitational systems consist of the `Ricci
scalar' of the th power of the Riemann curvature. In 4 spacetime dimensions
this is the usual Einstein-YMH (EYMH) studied in \cite{Breitenlohner:1991aa,
Breitenlohner:1994di}, whose qualitative results we emulate exactly.Comment: 31 pages, 9 figure
Dynamics of Gravitating Magnetic Monopoles
According to previous work on magnetic monopoles, static regular solutions
are nonexistent if the vacuum expectation value of the Higgs field is
larger than a critical value , which is of the order of the
Planck mass. In order to understand the properties of monopoles for
, we investigate their dynamics numerically. If is
large enough (), a monopole expands exponentially and a
wormhole structure appears around it, regardless of coupling constants and
initial configuration. If is around , there are three
types of solutions, depending on coupling constants and initial configuration:
a monopole either expands as stated above, collapses into a black hole, or
comes to take a stable configuration.Comment: 11 pages, revtex, postscript figures; results for various initial
conditions are added; to appear in Phys. Rev.
The final fate of instability of Reissner-Nordstr\"om-anti-de Sitter black holes by charged complex scalar fields
We investigate instability of 4-dimensional Reissner-Nordstr\"om-anti-de
Sitter (RN-AdS) black holes with various topologies by charged scalar field
perturbations. We numerically find that the RN-AdS black holes become
unstable against the linear perturbations below a critical temperature. It is
analytically shown that charge extraction from the black holes occurs during
the unstable evolution. To explore the end state of the instability, we
perturbatively construct static black hole solutions with the scalar hair near
the critical temperature. It is numerically found that the entropy of the
hairly black hole is always larger than the one of the unstable RN-AdS
black hole in the microcanonical ensemble. Our results support the speculation
that the black hole with charged scalar hair always appears as the final fate
of the instability of the RN-AdS black hole.Comment: 9 pages, 4 figures. To appear in PR
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