500 research outputs found
Octonionic Selfduality for SuperMembranes
In this work we study the recently introduced octonionic duality for
membranes. Restricting the self - duality equations to seven space dimensions,
we provide various forms for them which exhibit the symmetries of the
octonionic and quaternionic structure. These forms may turn to be useful for
the question of the integrability of this system. Introducing a consistent
quadratic Poisson algebra of functions on the membrane we are able to factorize
the time dependence of the self - duality equations. We further give the
general linear embeddings of the three dimensional system into the seven
dimensional one using the invariance of the self-duality equations under the
exceptional group G_2.Comment: Latex file, 21 page
Anti-de Sitter Black Holes in Gauged N=8 Supergravity
We present new anti-de Sitter black hole solutions of gauged N=8, SO(8)
supergravity, which is the massless sector of the AdS_4\times S^7 vacuum of
M-theory. By focusing on the U(1)^4 Cartan subgroup, we find non-extremal 1, 2,
3 and 4 charge solutions. In the extremal limit, they may preserve up to 1/2,
1/4, 1/8 and 1/8 of the supersymmetry, respectively. In the limit of vanishing
SO(8) coupling constant, the solutions reduce to the familiar black holes of
the M_4\times T^7 vacuum, but have very different interpretation since there
are no winding states on S^7 and no U-duality. In contrast to the T^7
compactification, moreover, we find no static multi-center solutions. Also in
contrast, the S^7 fields appear "already dualized" so that the 4 charges may be
all electric or all magnetic rather than 2 electric and 2 magnetic. Curiously,
however, the magnetic solutions preserve no supersymmetries. We conjecture that
a subset of the extreme electric black holes preserving 1/2 the supersymmetry
may be identified with the S^7 Kaluza-Klein spectrum, with the non-abelian
SO(8) quantum numbers provided by the fermionic zero modes.Comment: 18 pages, Latex, minor notation improvements and references adde
More CFTs and RG Flows from Deforming M2/M5-Brane Horizon
Near-horizon geometry of coincident M2-branes at a conical singularity is
related to M-theory on AdS4 times an appropriate seven-dimensional manifold X7.
For X_7=N^{0,1,0}, squashing deformation is known to lead to spontaneous
(super) symmetry breaking from N=(3, 0) to N=(0, 1) in gauged AdS4
supergravity. Via AdS/CFT correspondence, it is interpreted as renormalization
group flow of strongly coupled three-dimensional field theory with SU(3)*SU(2)
global symmetry. The flow interpolates between N=(0,1) fixed point in the UV to
N=(3,0)fixed point in the IR. Evidences for the interpretation are found both
from critical points of the supergravity scalar potential and from conformal
dimension of relevant chiral primary operators at each fixed point. We also
analyze cases with X7=SO(5)/SO(3)_{max}, V_{5,2}(R), M^{1,1,1}, Q^{1,1,1} and
find that there is no nontrivial renormalization group flows. We extend the
analysis to Englert type vacua of M-theory. By analyzing de Wit-Nicolai
potential, we find that deformation of S7 gives rise to renormalization group
flow from N=8, SO(8) invariant UV fixed point to N=1, G_2 invariant IR fixed
point. For AdS_7 supergravity relevant for near-horizon geometry of coincident
M5-branes, we also point out a nontrivial renormalization group flow from N=1
superconformal UV fixed point to non-supersymmetric IR fixed point.Comment: 21 pages, Latex, 3 figure
On BPS preons, generalized holonomies and D=11 supergravities
We develop the BPS preon conjecture to analyze the supersymmetric solutions
of D=11 supergravity. By relating the notions of Killing spinors and BPS
preons, we develop a moving G-frame method (G=GL(32,R), SL(32,R) or Sp(32,R))
to analyze their associated generalized holonomies. As a first application we
derive here the equations determining the generalized holonomies of k/32
supersymmetric solutions and, in particular, those solving the necessary
conditions for the existence of BPS preonic (31/32) solutions of the standard
D=11 supergravity. We also show that there exist elementary preonic solutions,
i.e. solutions preserving 31 out of 32 supersymmetries in a Chern--Simons type
supergravity. We present as well a family of worldvolume actions describing the
motion of pointlike and extended BPS preons in the background of a D'Auria-Fre
type OSp(1|32)-related supergravity model. We discuss the possible implications
for M-theory.Comment: 11 pages, RevTeX Typos corrected, a short note and references adde
Integrable Symplectic Trilinear Interaction Terms for Matrix Membranes
Cubic interactions are considered in 3 and 7 space dimensions, respectively,
for bosonic membranes in Poisson Bracket form. Their symmetries and vacuum
configurations are discussed. Their associated first order equations are
transformed to Nahm's equations, and are hence seen to be integrable, for the
3-dimensional case, by virtue of the explicit Lax pair provided. The
constructions introduced also apply to commutator or Moyal Bracket analogues.Comment: 11 pages, LaTe
A Moyal Quantization of the Continuous Toda Field
Since the lightcone self dual spherical membrane, moving in flat target
backgrounds, has a direct correspondence with the Nahm equations
and the continuous Toda theory, we construct the Moyal deformations of the self
dual membrane in terms of the Moyal deformations of the continuous Toda theory.
This is performed by using the Weyl-Wigner-Moyal quantization technique of the
3D continuous Toda field equation, and its associated 2D continuous Toda
molecule, based on Moyal deformations of rotational Killing symmetry reductions
of Plebanski first heavenly equation associated with 4D Self Dual Gravity.Comment: 15 pages, revised Tex fil
All solutions of the localization equations for N=2 quantum black hole entropy
We find the most general bosonic solution to the localization equations
describing the contributions to the quantum entropy of supersymmetric black
holes in four-dimensional N=2 supergravity coupled to n_v vector multiplets.
This requires the analysis of the BPS equations of the corresponding off-shell
supergravity (including fluctuations of the auxiliary fields) with AdS2 \times
S2 attractor boundary conditions. Our work completes and extends the results of
arXiv:1012.0265 that were obtained for the vector multiplet sector, to include
the fluctuations of all the fields of the off-shell supergravity. We find that,
when the auxiliary SU(2) gauge field strength vanishes, the most general
supersymmetric configuration preserving four supercharges is labelled by n_v+1
real parameters corresponding to the excitations of the conformal mode of the
graviton and the scalars of the n_v vector multiplets. In the general case, the
localization manifold is labelled by an additional SU(2) triplet of one-forms
and a scalar function.Comment: 27 page
A cross-sectional survey to assess household sanitation practices associated with uptake of “Clean Team” serviced home toilets in Kumasi, Ghana
“Clean Team” provides serviced, free-standing toilets as a sanitation option in low-income areas of Kumasi, Ghana. A cross-sectional survey was carried out to assess sanitation and hygiene practices in 199 Clean Team households and 201 neighbouring, non-Clean Team households. Adults in non-Clean Team households were no more likely to report unsafe defecation (faeces not contained in a latrine) than their Clean Team neighbours, although their reliance on public toilets may lead to occasional unsafe practices. Children in Clean Team households used the household toilet from a younger age than those in non-Clean Team households, and their faeces were thus more often disposed of safely. Soap and water were more frequently found at the latrine in Clean Team households than in latrine-owning non-Clean Team households. Use of Clean Team toilets is likely to reduce faecal contamination of the environment through safer child defecation and stool disposal practices, and may increase the opportunity for post-defecation handwashing with soap. </jats:p
Intersections of quadrics, moment-angle manifolds, and Hamiltonian-minimal Lagrangian embeddings
We study the topology of Hamiltonian-minimal Lagrangian submanifolds N in C^m
constructed from intersections of real quadrics in a work of the first author.
This construction is linked via an embedding criterion to the well-known
Delzant construction of Hamiltonian toric manifolds. We establish the following
topological properties of N: every N embeds as a submanifold in the
corresponding moment-angle manifold Z, and every N is the total space of two
different fibrations, one over the torus T^{m-n} with fibre a real moment-angle
manifold R, and another over a quotient of R by a finite group with fibre a
torus. These properties are used to produce new examples of Hamiltonian-minimal
Lagrangian submanifolds with quite complicated topology.Comment: 14 pages, published version (minor changes
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