83 research outputs found
Extremal Black Holes as Bound States
We consider a simple static extremal multi-black hole solution with
constituents charged under different fields. Each of the constituents by
itself is an extremal dilatonic black hole of coupling a=\srt. For a special
case with two electrically and two magnetically charged black holes the
multi-black hole solution interpolates between the familiar
and solutions, depending on how many
black holes are placed at infinity. This proves the hypothesis that black holes
with the above dilaton couplings arise in string theory as bound states of
fundamental states with zero binding energy. We also generalize
the result to states where the action does not admit a single scalar truncation
and show that a wide class of dyonic black holes in toroidally compactified
string theory can be viewed as bound states of fundamental a=\srt black
holes.Comment: 9 pages, LaTex, to appear in PLB, references adde
Near Horizon Superspace
The adS_{p+2} x S^{d-p-2} geometry of the near horizon branes is promoted to
a supergeometry: the solution of the supergravity constraints for the vielbein,
connection and form superfields are found. This supergeometry can be used for
the construction of new superconformal theories. We also discuss the
Green-Schwarz action for a type IIB string on adS_5 x S_5.Comment: 11 pages, LaTe
The GS String Action on AdS_5 x S^5
We present a simple form of the Type IIB string action on .
The result is achieved by fixing -symmetry in the Killing spinor gauge
defined by the projector of the Killing spinor of the D3 brane. We show
explicitly that in this gauge the superspace is greatly simplified which is the
crucial ingredient for the simple string action.Comment: LaTex, 8 page
Holography in Superspace
The AdS/CFT correspondence identifies the coordinates of the conformal
boundary of anti-de Sitter space with the coordinates of the conformal field
theory. We generalize this identification to theories formulated in superspace.
As an application of our results, we study a class of Wilson loops in N=4 SYM
theory. A gauge theory computation shows that the expectation values of these
loops are invariant under a local kappa-symmetry, except at intersections. We
identify this with the kappa-invariance of the associated string worldsheets in
the corresponding bulk superspace.Comment: 36 pages, LaTeX, references adde
A Construction of Killing Spinors on S^n
We derive simple general expressions for the explicit Killing spinors on the
n-sphere, for arbitrary n. Using these results we also construct the Killing
spinors on various AdS x Sphere supergravity backgrounds, including AdS_5 x
S^5$, AdS_4 x S^7 and AdS_7 x S^4. In addition, we extend previous results to
obtain the Killing spinors on the hyperbolic spaces H^n.Comment: 11 pages, LaTe
D1 and D5-Brane Actions in AdS_m x S^n
The kappa-invariant and supersymmetric actions of D1 and D5-branes in AdS_3 x
S^3 are investigated, as well as the action of a D5-brane in an AdS_5 x S^5
background. The action of a D5-brane lying totally in an AdS_3 x S^3 background
is found. Some progress was made towards finding the action for the D5-brane
free to move in the whole AdS_3 x S^3 x T^4 space, however the supersymmetric
action found here is not kappa-invariant and the reasons the method used did
not find a kappa-invariant solution are discussed.Comment: 17pp, Latex, improved explanations, a definition adde
Supersymmetry and Dual String Solitons
We present new classes of string-like soliton solutions in (; ),
(; ) and (; ) heterotic string theory. Connections are made
between the solution-generating subgroup of the -duality group of the
compactification and the number of spacetime supersymmetries broken. Analogous
solutions are also noted in (; ) compactifications, where a
different form of supersymmetry breaking arises.Comment: 13 pages, harvmac, (missing references added
A Simple Particle Action from a Twistor Parametrization of AdS_5
The SO(4,2) isometries of AdS_5 are realized non-linearly on its
horospherical coordinates (x^m,\rho). On the other hand, Penrose twistors have
long been known to linearly realize these symmetries on 4-dimensional Minkowski
space, the boundary of AdS_5, parametrized by x^m. Here we extend the twistor
construction and define a pair of twistors, allowing us to include a radial
coordinate in the construction. The linear action of SO(4,2) on the twistors
induces the correct isometries of AdS_5. We apply this new construction to the
study of the dynamics of a massive particle in AdS_5. We show that in terms of
the twistor variables the action takes a simple form of a 1-dimensional gauge
theory. Our result might open up the possibility to find a simple worldvolume
action also for the string propagating on AdS_5.Comment: 11 pages, LaTe
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