274 research outputs found

### Wess-Zumino sigma models with non-Kahlerian geometry

Supersymmetry of the Wess-Zumino (N=1, D=4) multiplet allows field equations
that determine a larger class of geometries than the familiar Kahler manifolds,
in which covariantly holomorphic vectors rather than a scalar superpotential
determine the forces. Indeed, relaxing the requirement that the field equations
be derivable from an action leads to complex flat geometry. The
Batalin-Vilkovisky formalism is used to show that if one requires that the
field equations be derivable from an action, we once again recover the
restriction to Kahler geometry, with forces derived from a scalar
superpotential.Comment: 13 pages, Late

### Hypermultiplets and hypercomplex geometry from 6 to 3 dimensions

The formulation of hypermultiplets that has been developed for 5-dimensional
matter multiplets is by dimensional reductions translated into the appropriate
spinor language for 6 and 4 dimensions. We also treat the theories without
actions that have the geometrical structure of hypercomplex geometry. The
latter is the generalization of hyper-Kaehler geometry that does not require a
Hermitian metric and hence corresponds to field equations without action. The
translation tables of this paper allow the direct application of superconformal
tensor calculus for the hypermultiplets using the available Weyl multiplets in
6 and 4 dimensions. Furthermore, the hypermultiplets in 3 dimensions that
result from reduction of vector multiplets in 4 dimensions are considered,
leading to a superconformal formulation of the c-map and an expression for the
main geometric quantities of the hyper-Kaehler manifolds in the image of this
map.Comment: 18 pages; v2: several clarifications in text and formulae, version to
appear in Class.Quantum Gravit

### The identification of conformal hypercomplex and quaternionic manifolds

We review the map between hypercomplex manifolds that admit a closed
homothetic Killing vector (i.e. `conformal hypercomplex' manifolds) and
quaternionic manifolds of 1 dimension less. This map is related to a method for
constructing supergravity theories using superconformal techniques. An explicit
relation between the structure of these manifolds is presented, including
curvatures and symmetries. An important role is played by `\xi
transformations', relating connections on quaternionic manifolds, and a new
type `\hat\xi transformations' relating complex structures on conformal
hypercomplex manifolds. In this map, the subclass of conformal hyper-Kaehler
manifolds is mapped to quaternionic-Kaehler manifolds.Comment: 22 pages, 2 figures, Contribution to the proceedings volume for the
Conference "Symmetry in Geometry and Physics" in honour of Dmitri
Alekseevsky, September 200

### Pure de Sitter Supergravity

Using superconformal methods we derive an explicit de Sitter supergravity
action invariant under spontaneously broken local ${\cal N}=1$ supersymmetry.
The supergravity multiplet interacts with a nilpotent goldstino multiplet. We
present a complete locally supersymmetric action including the graviton and the
fermionic fields, gravitino and goldstino, no scalars. In the global limit when
supergravity multiplet decouples, our action reproduces the Volkov-Akulov
theory. In the unitary gauge where goldstino vanishes we recover pure
supergravity with the positive cosmological constant. The classical equations
of motion, with all fermions vanishing, have a maximally symmetric solution: de
Sitter space.Comment: 22 pages, version to appear in PRD; v4: minor typos corrected; v5:
correction of torsion lagrangian (2.2); v6: Minor error in Sec.4.3 corrected.
This simplifies previous proof that any zero mode vanishes identicall

### Effective supergravity descriptions of superstring cosmology

This text is a review of aspects of supergravity theories that are relevant
in superstring cosmology. In particular, it considers the possibilities and
restrictions for `uplifting terms', i.e. methods to produce de Sitter vacua. We
concentrate on N=1 and N=2 supergravities, and the tools of superconformal
methods, which clarify the structure of these theories. Cosmic strings and
embeddings of target manifolds of supergravity theories in others are discussed
in short at the end.Comment: 12 pages, contribution to the proceedings of the 2nd international
conference on Quantum Theories and Renormalization Group in Gravity and
Cosmology, Barcelona, July 11-15, 2006, Journal of Physics

### Conformal Theory of M2, D3, M5 and `D1+D5' Branes

The bosonic actions for M2, D3 and M5 branes in their own d-dimensional
near-horizon background are given in a manifestly SO(p+1,2) x SO(d-p-1)
invariant form (p=2,3,5). These symmetries result from a breakdown of ISO(d,2)
(with d=10 for D3 and d=11 for M2 and M5) symmetry by the Wess-Zumino term and
constraints. The new brane actions, reduce after gauge-fixing and solving
constraints to (p+1) dimensional interacting field theories with a non-linearly
realized SO(p+1,2) conformal invariance. We also present an interacting
two-dimensional conformal field theory on a D-string in the near-horizon
geometry of a D1+D5 configuration.Comment: 32 pages, two figures, Latex. A version to appear in JHEP. A comment
is added on infinite dimensional Kac-Moody type symmetry of D1+D5 system
observed by Brandt, Gomis, Sim'o

- âŠ