9,388 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
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
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.
Patching DFT, T-duality and Gerbes
We clarify the role of the dual coordinates as described from the
perspectives of the Buscher T-duality rules and Double Field Theory. We show
that the T-duality angular dual coordinates cannot be identified with Double
Field Theory dual coordinates in any of the proposals that have been made in
the literature for patching the doubled spaces. In particular, we show with
explicit examples that the T-duality angular dual coordinates can have
non-trivial transition functions over a spacetime and that their identification
with the Double Field Theory dual coordinates is in conflict with proposals in
which the latter remain inert under the patching of the B-field. We then
demonstrate that the Double Field Theory coordinates can be identified with
some C-space coordinates and that the T-dual spaces of a spacetime are
subspaces of the gerbe in C-space. The construction provides a description of
both the local symmetry and the T-dual spaces of spacetime.Comment: minor changes, references adde
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