545 research outputs found
Performance-based financing as a health system reform : mapping the key dimensions for monitoring and evaluation
Peer reviewedPublisher PD
Supergravity Duals to the Noncommutative N=4 SYM theory in the Infinite Momentum Frame
In this work the construction of supergravity duals to the noncommutative
SYM theory in the infinite momentum frame but with constant
momentum density is attempted. In the absence of the content of
noncommutativity, it has been known for some time that the previous
correspondence should be replaced by the
(with denoting the generalized Kaigorodov spacetime) correspondence
with the pp-wave propagating on the BPS brane worldvolume. Interestingly
enough, putting together the two contents, i.e., the introduction of
noncommutativity and at the same time that of the pp-wave along the brane
worldvolume, leads to quite nontrivial consequences such as the emergence of
``time-space'' noncommutativity in addition to the ``space-space''
noncommutativity in the manifold on which the dual gauge theory is defined.
Taking the gravity decoupling limit, it has been realized that for small ,
the solutions all reduce to geometry confirming our
expectation that the IR dynamics of the dual gauge theory should be unaffected
by the noncommutativity while as , the solutions start to deviate
significantly from limit indicating that the UV dynamics of
the dual gauge theory would be heavily distorted by the effect of
noncommutativity.Comment: 21 pages, Latex, One expression changed, a reference added, to appear
in Phys. Rev.
Assessing Communities of Practice in health policy : A conceptual framework as a first step towards empirical research
Peer reviewe
Non-extremal black holes from the generalised r-map
We review the timelike dimensional reduction of a class of five-dimensional
theories that generalises 5D, N = 2 supergravity coupled to vector multiplets.
As an application we construct instanton solutions to the four-dimensional
Euclidean theory, and investigate the criteria for solutions to lift to static
non-extremal black holes in five dimensions.
We focus specifically on two classes of models: STU-like models, and models
with a block diagonal target space metric. For STU-like models the second order
equations of motion of the four-dimensional theory can be solved explicitly,
and we obtain the general solution. For block diagonal models we find a
restricted class of solutions, where the number of independent scalar fields
depends on the number of blocks. When lifting these solutions to five
dimensions we show, by explicit calculation, that one obtains static
non-extremal black holes with scalar fields that take finite values on the
horizon only if the number of integration constants reduces by exactly half.Comment: 22 pages. Based on talk by OV at "Black Objects in Supergravity
School" (BOSS2011), INFN, Frascati, Italy, 9-13 May, 201
Extensions of AdS_5 x S^5 and the Plane-wave Superalgebras and Their Realization in the Tiny Graviton Matrix Theory
In this paper we consider all consistent extensions of the AdS_5 x S^5
superalgebra, psu(2,2|4), to incorporate brane charges by introducing both
bosonic and fermionic (non)central extensions. We study the Inonu-Wigner
contraction of the extended psu(2,2|4) under the Penrose limit to obtain the
most general consistent extension of the plane-wave superalgebra and compare
these extensions with the possible BPS (flat or spherical) brane configurations
in the plane-wave background. We give an explicit realization of some of these
extensions in terms of the Tiny Graviton Matrix Theory (TGMT)[hep-th/0406214]
which is the 0+1 dimensional gauge theory conjectured to describe the DLCQ of
strings on the AdS_5 x S^5 and/or the plane-wave background.Comment: 27 pages, LaTe
Cosmological solutions from fake N=2 EYM supergravity
We characterise the (fake) supersymmetric solutions of Wick-rotated N=2 d=4
gauged supergravity coupled to non-Abelian vector multiplets. In the time-like
case we obtain generalisations of Kastor & Traschen's cosmological black holes:
they have a specific time-dependence and the base-space must be 3-dimensional
hyperCR/Gauduchon-Tod space. In the null-case, we find that the metric has a
holonomy contained in Sim(2), give a general characterisation of the solutions,
and give some examples. Finally, we point out that in some cases the solutions
we found are non-BPS solutions to N=2 d=4 supergravity coupled to vector
multiplets.Comment: 30 pages. Comments and references added, typos correcte
All the supersymmetric solutions of N=1,d=5 ungauged supergravity
We classify the supersymmetric solutions of ungauged N=1 d=5 SUGRA coupled to
vector multiplets and hypermultiplets. All the solutions can be seen as
deformations of solutions with frozen hyperscalars. We show explicitly how the
5-dimensional Reissner-Nordstrom black hole is deformed when hyperscalars are
living on SO(4,1)/SO(4) are turned on, reducing its supersymmetry from 1/2 to
1/8. We also describe in the timelike and null cases the solutions that have
one extra isometry and can be reduced to N=2,d=4 solutions. Our formulae allows
the uplifting of certain N=2,d=4 black holes to N=1,d=5 black holes on KK
monopoles or to pp-waves propagating along black strings.Comment: Some typos fixed and some paragraphs improved. 44 pages, Latex 2e
file, no figures. Version to be published in JHE
On d=4,5,6 Vacua with 8 Supercharges
We show how all known N=2, d=4,5,6 maximally supersymmetric vacua (Hpp-waves
and aDSxS solutions) are related through dimensional reduction/oxidation
preserving all the unbroken supersymmetries. In particular we show how the N=2,
d=5 family of vacua (which are the near-horizon geometry of supersymmetric
rotating black holes) interpolates between aDS_2xS^3 and aDS_3xS^2 in parameter
space and how it can be dimensionally reduced to an N=2, d=4 dyonic
Robinson-Bertotti solution with geometry aDS_2xS^2 and oxidized to an N=2, d=6
solution with aDS_3xS^3 geometry (which is the near-horizon of the self-dual
string).Comment: Latex2e, 19 pages, 1 figure. v2: typos corrected, refs. added. v3:
very minor corrections, more refs. added, version to be published in
Classical and Quantum Gravit
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