5,912 research outputs found
De Sitter in Extended Supergravity
We show that known de Sitter solutions in extended gauged supergravity
theories are interrelated via a web of supersymmetry-breaking truncations. In
particular, all N=8 models reduce to a subset of the N=4 possibilities.
Furthermore, a different subset of the N=4 models can be truncated to stable de
Sitter vacua in N=2 theories. In addition to relations between the known cases,
we also find new (un)stable models.Comment: 16 page
On the construction of variant supergravities in D=11, D=10
We construct with a geometric procedure the supersymmetry transformation laws
and Lagrangian for all the ``variant'' D=11 and D=10 Type IIA supergravities.
We identify into our classification the D=11 and D=10 Type IIA ``variant''
theories first introduced by Hull performing T-duality transformation on both
spacelike and timelike circles. We find in addition a set of D=10 Type IIA
``variant'' supergravities that can not be obtained trivially from eleven
dimensions compactifying on a circle.Comment: 21 pages, Late
Domain Wall/Cosmology correspondence in (AdS/dS)_6 x S^4 geometries
We investigate the ten dimensional origin of six dimensional F_4 variant
supergravity with supersymmetric de Sitter background. We address first the
issue of spontaneous compactification, showing that it consists of a warped
compactification on a four sphere of a variant massive type IIA supergravity.
Moreover we illustrate how the known D4-D8 brane solution, whose near horizon
geometry yields AdS_6 x S^4, is accordingly modified to a system including
Euclidean branes. Finally, we discuss the relation between this latter solution
and the D4-D8 brane system, showing how it represents a generalisation of the
DW/Cosmology correspondence.Comment: 11 pages, LaTe
The geometry of supersymmetric coset models and superconformal algebras
An on-shell formulation of (p,q), 2\leq p \leq 4, 0\leq q\leq 4,
supersymmetric coset models with target space the group G and gauge group a
subgroup H of G is given. It is shown that there is a correspondence between
the number of supersymmetries of a coset model and the geometry of the coset
space G/H. The algebras of currents of supersymmetric coset models are
superconformal algebras. In particular, the algebras of currents of (2,2) and
(4,0) supersymmetric coset models are related to the N=2 Kazama-Suzuki and N=4
Van Proeyen superconformal algebras correspondingly.Comment: pages 2
D=6, N=2, F(4)-Supergravity with supersymmetric de Sitter Background
We show that there exists a supersymmetric de Sitter background for the D=6,
N=2, F(4) supergravity preserving the compact R-symmetry and gauging with
respect to the conventional Anti de Sitter version of the theory. We construct
the gauged matter coupled F(4) de Sitter supergravity explicitly and show that
it contains ghosts in the vector sector.Comment: 19 pages, Late
Gravitational Duality, Branes and Charges
It is argued that D=10 type II strings and M-theory in D=11 have D-5 branes
and 9-branes that are not standard p-branes coupled to anti-symmetric tensors.
The global charges in a D-dimensional theory of gravity consist of a momentum
and a dual D-5 form charge , which is related to the
NUT charge. On dimensional reduction, P gives the electric charge and K the
magnetic charge of the graviphoton. The charge K is constructed and shown to
occur in the superalgebra and BPS bounds in , and leads to a NUT-charge
modification of the BPS bound in D=4. is carried by Kaluza-Klein monopoles,
which can be regarded as D-5 branes. Supersymmetry and U-duality imply that the
type IIB theory has (p,q) 9-branes. Orientifolding with 32 (0,1) 9-branes gives
the type I string, while modding out by a related discrete symmetry with 32
(1,0) 9-branes gives the SO(32) heterotic string. Symmetry enhancement, the
effective world-volume theories and the possibility of a twelve dimensional
origin are discussed.Comment: 54 pages, TeX, Phyzzx Macro. Added referenc
The many faces of OSp(1|32)
We show that the complete superalgebra of symmetries, including central
charges, that underlies F-theories, M-theories and type II string theories in
dimensions 12, 11 and 10 of various signatures correspond to rewriting of the
same OSp(1|32) algebra in different covariant ways. One only has to distinguish
the complex and the unique real algebra. We develop a common framework to
discuss all signatures theories by starting from the complex form of OSp(1|32).
Theories are distinguished by the choice of basis for this algebra. We
formulate dimensional reductions and dualities as changes of basis of the
algebra. A second ingredient is the choice of a real form corresponding to a
specific signature. The existence of the real form of the algebra selects
preferred spacetime signatures. In particular, we show how the real d=10 IIA
and IIB superalgebras for various signatures are related by generalized
T-duality transformations that not only involve spacelike but also timelike
directions. A third essential ingredient is that the translation generator in
one theory plays the role of a central charge operator in the other theory. The
identification of the translation generator in these algebras leads to the star
algebras of Hull, which are characterized by the fact that the positive
definite energy operator is not part of the translation generators. We apply
our results to discuss different T-dual pictures of the D-instanton solution of
Euclidean IIB supergravity.Comment: 30 pages, Latex, using lscape.st
T-duality and spacetime supersymmetry
We analyze in detail the possible breaking of spacetime supersymmetry under
T-duality transformations. We find that when appropiate world-sheet effects are
taken into account apparent puzzles concerning supersymmetry in spacetime are
solved. We study T-duality in general heterotic -models analyzing
possible anomalies, and we find some modifications of Buscher's rules. We then
work out a simple but representative example which contains most of the
difficulties. We also consider the issue of supersymmetry versus duality for
marginal deformations of WZW models and present a mechanism that restores
supersymmetry dynamically in the effective theory.Comment: 28 pages, harvmac/ a few corrections and references added; to appear
in Nuclear Physics
Multiple fundamental strings and waves to non-linear order in the background fields
The Chern-Simons actions of the multiple fundamental string and the multiple
gravitational wave are established to full order in the background fields.
Gauge invariance is checked. Special attention is drawn to the non-Abelian
gauge transformations of the world-volume fields.Comment: Latex, 15 pages, 2 figures Edit: modified text throughout paper to
clarify, corrected mistake in discussion, added appendix and figure, added
reference
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