9,399 research outputs found
Harmonic Superspaces and Superconformal Fields
Representations of four-dimensional superconformal groups on harmonic
superfields are discussed. It is argued that any representation can be given as
a superfield on many superflag manifolds. Representations on analytic
superspaces do not require constraints. We discuss short representations and
how to obtain them as explicit products of fundamental fields. We also discuss
superfields that transform under supergroups.Comment: 7 pages, JHEP Proceedings style. Contribution to the Proceedings of
the TMR Conference "Non-Perturbative Quantum Effects 2000," Paris, September
200
The supermembrane revisited
The M2-brane is studied from the perspective of superembeddings. We review
the derivation of the M2-brane dynamics and the supergravity constraints from
the standard superembedding constraint and we discuss explicitly the induced
d=3, N=8 superconformal geometry on the worldvolume. We show that the gauged
supermembrane, for a target space with a U(1) isometry, is the standard
D2-brane in a type IIA supergravity background. In particular, the D2-brane
action, complete with the Dirac-Born-Infeld term, arises from the gauged
Wess-Zumino worldvolume 4-form via the brane action principle. The discussion
is extended to the massive D2-brane considered as a gauged supermembrane in a
massive D=11 superspace background. Type IIA supergeometry is derived using
Kaluza-Klein techniques in superspace.Comment: Latex, 46 pages, clarifying remarks and references adde
L-branes
The superembedding approach to -branes is used to study a class of
-branes which have linear multiplets on the worldvolume. We refer to these
branes as L-branes. Although linear multiplets are related to scalar multiplets
(with 4 or 8 supersymmetries) by dualising one of the scalars of the latter to
a -form field strength, in many geometrical situations it is the linear
multiplet version which arises naturally. Furthermore, in the case of 8
supersymmetries, the linear multiplet is off-shell in contrast to the scalar
multiplet. The dynamics of the L-branes are obtained by using a systematic
procedure for constructing the Green-Schwarz action from the superembedding
formalism. This action has a Dirac-Born-Infeld type structure for the -form.
In addition, a set of equations of motion is postulated directly in superspace,
and is shown to agree with the Green-Schwarz equations of motion.Comment: revised version, minor changes, references added, 22 pages, no
figures, LaTe
Note on two-dimensional nonlinear gauge theories
A two-dimensional nonlinear gauge theory that can be proposed for
generalization to higher dimensions is derived by means of cohomological
arguments.Comment: 12 pages, LaTeX 2.
Kappa-symmetric higher derivative terms in brane actions
Using the superembedding formalism we construct supermembrane actions with
higher derivative terms which can be viewed as possible higher order terms in
effective actions. In particular, we provide the first example of an action for
an extended supersymmetric object with fully -symmetric extrinsic
curvature terms.Comment: 16 pages, Latex, References adde
On higher-order corrections in M theory
A theoretical analysis of higher-order corrections to D=11 supergravity is
given in a superspace framework. It is shown that any deformation of D=11
supergravity for which the lowest-dimensional component of the four-form
vanishes is trivial. This implies that the equations of motion of D=11
supergravity are specified by an element of a certain spinorial cohomology
group and generalises previous results obtained using spinorial or pure spinor
cohomology to the fully non-linear theory. The first deformation of the theory
is given by an element of a different spinorial cohomology group with
coefficients which are local tensorial functions of the massless supergravity
fields. The four-form Bianchi Identities are solved, to first order and at
dimension , in the case that the lowest-dimensional component of
is non-zero. Moreover, it is shown how one can calculate the first-order
correction to the dimension-zero torsion and thus to the supergravity equations
of motion given an explicit expression for this object in terms of the
supergravity fields. The version of the theory with both a four-form and a
seven-form is discussed in the presence of the five-brane anomaly-cancelling
term. It is shown that the supersymmetric completion of this term exists and it
is argued that it is the unique anomaly-cancelling invariant at this dimension
which is at least quartic in the fields. This implies that the first
deformation of the theory is completely determined by the anomaly term from
which one can, in principle, read off the corrections to all of the superspace
field strength tensors.Comment: 32 pages. v2: Two references added in the text; footnote adde
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