10,626 research outputs found
The Tensor Hierarchies of Pure N=2,d=4,5,6 Supergravities
We study the supersymmetric tensor hierarchy of pure (gauged) N=2,d=4,5,6
supergravity and compare them with those of the pure, ungauged, theories
(worked out by Gomis and Roest for d=5) and the predictions of the Kac-Moody
approach made by Kleinschmidt and Roest. We find complete agreement in the
ungauged case but we also find that, after gauging, new Stueckelberg symmetries
reduce the number of independent "physical" top-forms. The analysis has to be
performed to all orders in fermion fields.
We discuss the construction of the worldvolume effective actions for the
p-branes which are charged with respect to the (p+1)-form potentials and the
relations between the tensor hierarchies and p-branes upon dimensional
reduction.Comment: LaTeX2e file, 20 pages, 1 figure Results refined by extension of the
analysis to all orders in fermion
A Massive S-duality in 4 dimensions
We reduce the Type IIA supergravity theory with a generalized Scherk-Schwarz
ansatz that exploits the scaling symmetry of the dilaton, the metric and the NS
2-form field. The resulting theory is a new massive, gauged supergravity theory
in four dimensions with a massive 2-form field and a massive 1-form field. We
show that this theory is S-dual to a theory with a massive vector field and a
massive 2-form field, which are dual to the massive 2-form and 1-form fields in
the original theory, respectively. The S-dual theory is shown to arise from a
Scherk-Schwarz reduction of the heterotic theory. Hence we establish a massive,
S-duality type relation between the IIA theory and the heterotic theory in four
dimensions. We also show that the Lagrangian for the new four dimensional
theory can be put in the most general form of a D=4, N=4 gauged Lagrangian
found by Schon and Weidner, in which (part of) the SL(2) group has been gauged.Comment: 20 pages, references adde
VLTI/MIDI 10 micron interferometry of the forming massive star W33A
We report on resolved interferometric observations with VLTI/MIDI of the
massive young stellar object (MYSO) W33A. The MIDI observations deliver
spectrally dispersed visibilities with values between 0.03 and 0.06, for a
baseline of 45m over the wavelength range 8-13 micron. The visibilities
indicate that W33A has a FWHM size of approximately 120AU (0.030'') at 8 micron
which increases to 240AU at 13 micron, scales previously unexplored among
MYSOs. This observed trend is consistent with the temperature falling off with
distance. 1D dust radiative transfer models are simultaneously fit to the
visibility spectrum, the strong silicate feature and the shape of the mid
infrared spectral energy distribution (SED). For any powerlaw density
distribution, we find that the sizes (as implied by the visibilities) and the
stellar luminosity are incompatible. A reduction to a third of W33A's
previously adopted luminosity is required to match the visibilities; such a
reduction is consistent with new high resolution 70 micron data from Spitzer's
MIPSGAL survey. We obtain best fits for models with shallow dust density
distributions of r^(-0.5) and r^(-1.0) and for increased optical depth in the
silicate feature produced by decreasing the ISM ratio of graphite to silicates
and using optical grain properties by Ossenkopf et al. (1992).Comment: 4 pages, 4 figures. Accepted for ApJ letter
N=2 supergravity in five dimensions revisited
We construct matter-coupled N=2 supergravity in five dimensions, using the
superconformal approach. For the matter sector we take an arbitrary number of
vector-, tensor- and hyper-multiplets. By allowing off-diagonal vector-tensor
couplings we find more general results than currently known in the literature.
Our results provide the appropriate starting point for a systematic search for
BPS solutions, and for applications of M-theory compactifications on Calabi-Yau
manifolds with fluxes.Comment: 35 pages; v.2: A sign changed in a bilinear fermion term in (5.7
Minimal Stability in Maximal Supergravity
Recently, it has been shown that maximal supergravity allows for
non-supersymmetric AdS critical points that are perturbatively stable. We
investigate this phenomenon of stability without supersymmetry from the
sGoldstino point of view. In particular, we calculate the projection of the
mass matrix onto the sGoldstino directions, and derive the necessary conditions
for stability. Indeed we find a narrow window allowing for stable SUSY breaking
points. As a by-product of our analysis, we find that it seems impossible to
perturb supersymmetric critical points into non-supersymmetric ones: there is a
minimal amount of SUSY breaking in maximal supergravity.Comment: 27 pages, 1 figure. v2: two typos corrected, published versio
Anti-de Sitter Supersymmetry
We give a pedagogical introduction to certain aspects of supersymmetric field
theories in anti-de Sitter space. Among them are the presence of masslike terms
in massless wave equations, irreducible unitary representations and the
phenomenon of multiplet shortening.Comment: Lectures presented by B. de Wit at the Winter School of Theoretical
Physics, Polanica, Poland, February 1999. 23 pp., LateX file, requires
packages latexsym, amsfonts, cl2emult.cl
Symmetric Potentials of Gauged Supergravities in Diverse Dimensions and Coulomb Branch of Gauge Theories
A class of conformally flat and asymptotically anti-de Sitter geometries
involving profiles of scalar fields is studied from the point of view of gauged
supergravity. The scalars involved in the solutions parameterise the
SL(N,R)/SO(N) submanifold of the full scalar coset of the gauged supergravity,
and are described by a symmetric potential with a universal form. These
geometries descend via consistent truncation from distributions of D3-branes,
M2-branes, or M5-branes in ten or eleven dimensions. We exhibit analogous
solutions asymptotic to AdS_6 which descend from the D4-D8-brane system. We
obtain the related six-dimensional theory by consistent reduction from massive
type IIA supergravity. All our geometries correspond to states in the Coulomb
branch of the dual conformal field theories. We analyze linear fluctuations of
minimally coupled scalars and find both discrete and continuous spectra, but
always bounded below.Comment: Latex, 38 pages, minor correction
The Matrix Theory S-Matrix
The technology required for eikonal scattering amplitude calculations in
Matrix theory is developed. Using the entire supersymmetric completion of the
v^4/r^7 Matrix theory potential we compute the graviton-graviton scattering
amplitude and find agreement with eleven dimensional supergravity at tree
level.Comment: 10 pages, RevTeX, no figure
More on Membranes in Matrix Theory
We study noncompact and static membrane solutions in Matrix theory. Demanding
axial symmetry on a membrane embedded in three spatial dimensions, we obtain a
wormhole solution whose shape is the same with the catenoidal solution of
Born-Infeld theory. We also discuss another interesting class of solutions,
membranes embedded holomorphically in four spatial dimensions, which are 1/4
BPS.Comment: 7 pages, LaTeX; expanded to treat matrix membrane solutions with
electric flux, equivalently fundamental strings; to appear in Phys. Rev.
Supergravity, Supermembrane and M(atrix) model on PP-Waves
In the first part of this paper, we study the back-reaction of large-N light
cone momentum on the maximally supersymmetric anti-pp-wave background. This
gives the type IIA geometry of large-N D0-branes on curved space with fluxes.
By taking an appropriate decoupling limit, we conjecture a new duality between
string theory on that background and dual field theory on D0-branes which we
derive by calculating linear coupling terms. Agreement of decoupling
quantities, SO(3) \times SO(6) isometry and Higgs branch on both theories are
shown. Also we find whenever dual field theory is weakly coupled, the curvature
of the geometry is large. In the second part of this paper, we derive the
supermembrane action on a general pp-wave background only through the
properties of null Killing vector and through this, derive the Matrix model.Comment: 19 pages, LaTeX. v2: corrected interpretation of supergravity
solutio
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