399 research outputs found
Explicit Orbit Classification of Reducible Jordan Algebras and Freudenthal Triple Systems
We determine explicit orbit representatives of reducible Jordan algebras and
of their corresponding Freudenthal triple systems. This work has direct
application to the classification of extremal black hole solutions of N = 2, 4
locally supersymmetric theories of gravity coupled to an arbitrary number of
Abelian vector multiplets in D = 4, 5 space-time dimensions.Comment: 18 pages. Updated to match published versio
Partition Functions, the Bekenstein Bound and Temperature Inversion in Anti-de Sitter Space and its Conformal Boundary
We reformulate the Bekenstein bound as the requirement of positivity of the
Helmholtz free energy at the minimum value of the function L=E- S/(2\pi R),
where R is some measure of the size of the system. The minimum of L occurs at
the temperature T=1/(2\pi R). In the case of n-dimensional anti-de Sitter
spacetime, the rather poorly defined size R acquires a precise definition in
terms of the AdS radius l, with R=l/(n-2). We previously found that the
Bekenstein bound holds for all known black holes in AdS. However, in this paper
we show that the Bekenstein bound is not generally valid for free quantum
fields in AdS, even if one includes the Casimir energy. Some other aspects of
thermodynamics in anti-de Sitter spacetime are briefly touched upon.Comment: Latex, 32 page
Non-extremal Black Holes, Harmonic Functions, and Attractor Equations
We present a method which allows to deform extremal black hole solutions into
non-extremal solutions, for a large class of supersymmetric and
non-supersymmetric Einstein-Vector-Scalar type theories. The deformation is
shown to be largely independent of the details of the matter sector. While the
line element is dressed with an additional harmonic function, the attractor
equations for the scalars remain unmodified in suitable coordinates, and the
values of the scalar fields on the outer and inner horizon are obtained from
their fixed point values by making specific substitutions for the charges. For
a subclass of models, which includes the five-dimensional STU-model, we find
explicit solutions.Comment: 33 page
Fake Supergravity and Domain Wall Stability
We review the generalized Witten-Nester spinor stability argument for flat
domain wall solutions of gravitational theories. Neither the field theory nor
the solution need be supersymmetric. Nor is the space-time dimension
restricted. We develop the non-trivial extension required for AdS-sliced domain
walls and apply this to show that the recently proposed "Janus" solution of
Type IIB supergravity is stable non-perturbatively for a broad class of
deformations. Generalizations of this solution to arbitrary dimension and a
simple curious linear dilaton solution of Type IIB supergravity are byproducts
of this work.Comment: 37 pages, 3 figures, v2: minor corrections, references and
acknowledgments adde
Stable de Sitter Vacua in 4 Dimensional Supergravity Originating from 5 Dimensions
The five dimensional stable de Sitter ground states in N=2 supergravity
obtained by gauging SO(1,1) symmetry of the real symmetric scalar manifold (in
particular a generic Jordan family manifold of the vector multiplets)
simultaneously with a subgroup R_s of the R-symmetry group descend to four
dimensional de Sitter ground states under certain conditions. First, the
holomorphic section in four dimensions has to be chosen carefully by using the
symplectic freedom in four dimensions; and second, a group contraction is
necessary to bring the potential into a desired form. Under these conditions,
stable de Sitter vacua can be obtained in dimensionally reduced theories (from
5D to 4D) if the semi-direct product of SO(1,1) with R^(1,1) together with a
simultaneous R_s is gauged. We review the stable de Sitter vacua in four
dimensions found in earlier literature for N=2 Yang-Mills Einstein supergravity
with SO(2,1) x R_s gauge group in a symplectic basis that comes naturally after
dimensional reduction. Although this particular gauge group does not descend
directly from five dimensions, we show that, its contraction does. Hence, two
different theories overlap in certain limits. Examples of stable de Sitter
vacua are given for the cases: (i) R_s=U(1)_R, (ii) R_s=SU(2)_R, (iii) N=2
Yang-Mills/Einstein Supergravity theory coupled to a universal hypermultiplet.
We conclude with a discussion regarding the extension of our results to
supergravity theories with more general homogeneous scalar manifolds.Comment: 54 page
Supersymmetric new brane-world
The quantum-induced dilatonic brane world (New Brane World) is created by
brane CFT quantum effects (giving effective brane tension) in accordance with
AdS/CFT set-up which also defines surface term. Considering the bosonic sector
of 5d gauged supergravity with single scalar and taking the boundary action as
predicted by supersymmetry, the possibility to supersymmetrize dilatonic New
Brane World is discussed. It is demonstrated that for a number of
superpotentials the flat SUSY dilatonic brane-world (with dynamically induced
brane dilaton) or quantum-induced de Sitter dilatonic brane-world (not Anti-de
Sitter one) where SUSY is broken by the quantum effects occurs. The analysis of
graviton perturbations indicates that gravity is localized on such branes.Comment: LaTeX 16 pages, misprints are correcte
On Symmetries of Extremal Black Holes with One and Two Centers
After a brief introduction to the Attractor Mechanism, we review the
appearance of groups of type E7 as generalized electric-magnetic duality
symmetries in locally supersymmetric theories of gravity, with particular
emphasis on the symplectic structure of fluxes in the background of extremal
black hole solutions, with one or two centers. In the latter case, the role of
an "horizontal" symmetry SL(2,R) is elucidated by presenting a set of
two-centered relations governing the structure of two-centered invariant
polynomials.Comment: 1+13 pages, 2 Tables. Based on Lectures given by SF and AM at the
School "Black Objects in Supergravity" (BOSS 2011), INFN - LNF, Rome, Italy,
May 9-13 201
Four Dimensional Conformal Supergravity From AdS Space
Exploring the role of conformal theories of gravity in string theory, we show
that the minimal (N=2) gauged supergravities in five dimensions induce the
multiplets and transformations of N=1 four dimensional conformal supergravity
on the spacetime boundary. N=1 Poincare supergravity can be induced by
explicitly breaking the conformal invariance via a radial cutoff in the 5d
space. The AdS/CFT correspondence relates the maximal gauged supergravity in
five dimensions to N=4 super Yang-Mills on the 4d spacetime boundary. In this
context we show that the conformal anomaly of the gauge theory induces
conformal gravity on the boundary of the space and that this theory, via the
renormalization group, encapsulates the gravitational dynamics of the skin of
asymptotically AdS spacetimes. Our results have several applications to the
AdS/CFT correspondence and the Randall-Sundrum scenario.Comment: 20 pages, LaTeX. v3. references and minor comments adde
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