2,604 research outputs found
Invariant Killing spinors in 11D and type II supergravities
We present all isotropy groups and associated groups, up to discrete
identifications of the component connected to the identity, of spinors of
eleven-dimensional and type II supergravities. The groups are products
of a Spin group and an R-symmetry group of a suitable lower dimensional
supergravity theory. Using the case of SU(4)-invariant spinors as a paradigm,
we demonstrate that the groups, and so the R-symmetry groups of
lower-dimensional supergravity theories arising from compactifications, have
disconnected components. These lead to discrete symmetry groups reminiscent of
R-parity. We examine the role of disconnected components of the groups
in the choice of Killing spinor representatives and in the context of
compactifications.Comment: 22 pages, typos correcte
Geometry of all supersymmetric type I backgrounds
We find the geometry of all supersymmetric type I backgrounds by solving the
gravitino and dilatino Killing spinor equations, using the spinorial geometry
technique, in all cases. The solutions of the gravitino Killing spinor equation
are characterized by their isotropy group in Spin(9,1), while the solutions of
the dilatino Killing spinor equation are characterized by their isotropy group
in the subgroup Sigma(P) of Spin(9,1) which preserves the space of parallel
spinors P. Given a solution of the gravitino Killing spinor equation with L
parallel spinors, L = 1,2,3,4,5,6,8, the dilatino Killing spinor equation
allows for solutions with N supersymmetries for any 0 < N =< L. Moreover for L
= 16, we confirm that N = 8,10,12,14,16. We find that in most cases the Bianchi
identities and the field equations of type I backgrounds imply a further
reduction of the holonomy of the supercovariant connection. In addition, we
show that in some cases if the holonomy group of the supercovariant connection
is precisely the isotropy group of the parallel spinors, then all parallel
spinors are Killing and so there are no backgrounds with N < L supersymmetries.Comment: 73 pages. v2: minor changes, references adde
Kappa symmetry, generalized calibrations and spinorial geometry
We extend the spinorial geometry techniques developed for the solution of
supergravity Killing spinor equations to the kappa symmetry condition for
supersymmetric brane probe configurations in any supergravity background. In
particular, we construct the linear systems associated with the kappa symmetry
projector of M- and type II branes acting on any Killing spinor. As an example,
we show that static supersymmetric M2-brane configurations which admit a
Killing spinor representing the SU(5) orbit of are generalized
almost hermitian calibrations and the embedding map is pseudo-holomorphic. We
also present a bound for the Euclidean action of M- and type II branes embedded
in a supersymmetric background with non-vanishing fluxes. This leads to an
extension of the definition of generalized calibrations which allows for the
presence of non-trivial Born-Infeld type of fields in the brane actions.Comment: 9 pages, latex, references added and minor change
All null supersymmetric backgrounds of N=2, D=4 gauged supergravity coupled to abelian vector multiplets
The lightlike supersymmetric solutions of N=2, D=4 gauged supergravity
coupled to an arbitrary number of abelian vector multiplets are classified
using spinorial geometry techniques. The solutions fall into two classes,
depending on whether the Killing spinor is constant or not. In both cases, we
give explicit examples of supersymmetric backgrounds. Among these BPS
solutions, which preserve one quarter of the supersymmetry, there are
gravitational waves propagating on domain walls or on bubbles of nothing that
asymptote to AdS_4. Furthermore, we obtain the additional constraints obeyed by
half-supersymmetric vacua. These are divided into four categories, that include
bubbles of nothing which are asymptotically AdS_4, pp-waves on domain walls,
AdS_3 x R, and spacetimes conformal to AdS_3 times an interval.Comment: 55 pages, uses JHEP3.cls. v2: Minor errors corrected, small changes
in introductio
M-Horizons
We solve the Killing spinor equations and determine the near horizon
geometries of M-theory that preserve at least one supersymmetry. The M-horizon
spatial sections are 9-dimensional manifolds with a Spin(7) structure
restricted by geometric constraints which we give explicitly. We also provide
an alternative characterization of the solutions of the Killing spinor
equation, utilizing the compactness of the horizon section and the field
equations, by proving a Lichnerowicz type of theorem which implies that the
zero modes of a Dirac operator coupled to 4-form fluxes are Killing spinors. We
use this, and the maximum principle, to solve the field equations of the theory
for some special cases and present some examples.Comment: 36 pages, latex. Reference added, minor typos correcte
Supersymmetric solutions of gauged five-dimensional supergravity with general matter couplings
We perform the characterization program for the supersymmetric configurations
and solutions of the , Supergravity Theory coupled to an
arbitrary number of vectors, tensors and hypermultiplets and with general
non-Abelian gaugins. By using the conditions yielded by the characterization
program, new exact supersymmetric solutions are found in the
model for the hyperscalars and with as the gauge group. The
solutions also content non-trivial vector and massive tensor fields, the latter
being charged under the U(1) sector of the gauge group and with selfdual
spatial components. These solutions are black holes with
near horizon geometry in the gauged version of the theory and for the ungauged
case we found naked singularities. We also analyze supersymmetric solutions
with only the scalars of the vector/tensor multiplets and the metric
as the non-trivial fields. We find that only in the null class the scalars
can be non-constant and for the case of constant we refine
the classification in terms of the contributions to the scalar potential.Comment: Minor changes in wording and some typos corrected. Version to appear
in Class. Quantum Grav. 38 page
All the timelike supersymmetric solutions of all ungauged d=4 supergravities
We determine the form of all timelike supersymmetric solutions of all N
greater or equal than 2, d=4 ungauged supergravities, for N less or equal than
4 coupled to vector supermultiplets, using the $Usp(n+1,n+1)-symmetric
formulation of Andrianopoli, D'Auria and Ferrara and the spinor-bilinears
method, while preserving the global symmetries of the theories all the way. As
previously conjectured in the literature, the supersymmetric solutions are
always associated to a truncation to an N=2 theory that may include
hypermultiplets, although fields which are eliminated in the truncations can
have non-trivial values, as is required by the preservation of the global
symmetry of the theories. The solutions are determined by a number of
independent functions, harmonic in transverse space, which is twice the number
of vector fields of the theory (n+1). The transverse space is flat if an only
if the would-be hyperscalars of the associated N=2 truncation are trivial.Comment: v3: Some changes in the introduction. Version to be published in JHE
Spinorial geometry and Killing spinor equations of 6-D supergravity
We solve the Killing spinor equations of 6-dimensional (1,0)-supergravity
coupled to any number of tensor, vector and scalar multiplets in all cases. The
isotropy groups of Killing spinors are Sp(1)\cdot Sp(1)\ltimes \bH (1),
U(1)\cdot Sp(1)\ltimes \bH (2), Sp(1)\ltimes \bH (3,4), , and , where in parenthesis is the number of supersymmetries
preserved in each case. If the isotropy group is non-compact, the spacetime
admits a parallel null 1-form with respect to a connection with torsion the
3-form field strength of the gravitational multiplet. The associated vector
field is Killing and the 3-form is determined in terms of the geometry of
spacetime. The Sp(1)\ltimes \bH case admits a descendant solution preserving
3 out of 4 supersymmetries due to the hyperini Killing spinor equation. If the
isotropy group is compact, the spacetime admits a natural frame constructed
from 1-form spinor bi-linears. In the and U(1) cases, the spacetime
admits 3 and 4 parallel 1-forms with respect to the connection with torsion,
respectively. The associated vector fields are Killing and under some
additional restrictions the spacetime is a principal bundle with fibre a
Lorentzian Lie group. The conditions imposed by the Killing spinor equations on
all other fields are also determined.Comment: 34 pages, Minor change
Three-dimensional N=8 conformal supergravity and its coupling to BLG M2-branes
This paper is concerned with the problem of coupling the N=8 superconformal
Bagger-Lambert-Gustavsson (BLG) theory to N=8 conformal supergravity in three
dimensions. We start by constructing the on-shell N=8 conformal supergravity in
three dimensions consisting of a Chern-Simons type term for each of the gauge
fields: the spin connection, the SO(8) R-symmetry gauge field and the spin 3/2
Rarita-Schwinger (gravitino) field. We then proceed to couple this theory to
the BLG theory. The final theory should have the same physical content, i.e.,
degrees of freedom, as the ordinary BLG theory. We discuss briefly the
properties of this "topologically gauged" BLG theory and why this theory may be
useful.Comment: 20 pages, v2: references and comments added, presentation in section
3.2 extended. v3: misprints and a sign error corrected, version published in
JHE
Superembeddings, Non-Linear Supersymmetry and 5-branes
We examine general properties of superembeddings, i.e., embeddings of
supermanifolds into supermanifolds. The connection between an embedding
procedure and the method of non-linearly realised supersymmetry is clarified,
and we demonstrate how the latter arises as a special case of the former. As an
illustration, the super-5-brane in 7 dimensions, containing a self-dual 3-form
world-volume field strength, is formulated in both languages, and provides an
example of a model where the embedding condition does not suffice to put the
theory on-shell.Comment: plain tex, 28 p
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