1,307 research outputs found

### Coset construction of a D-brane gauge field

D-branes have a world-volume U(1) gauge field A whose field strength F = dA
gives rise to a Born-Infeld term in the D-brane action. Supersymmetry and kappa
symmetry transformations of A are traditionally inferred by the requirement
that the Born-Infeld term is consistent with both supersymmetry and kappa
symmetry of the D-brane action. In this paper, we show that integrability of
the assigned supersymmetry transformations leads to a extension of the standard
supersymmetry algebra that includes a fermionic central charge. We construct a
superspace one-form on an enlarged superspace related by a coset construction
to this centrally extended algebra whose supersymmetry and kappa symmetry
transformations are derived, rather than inferred. It is shown that under
pullback, these transformations are of the form expected for the D-brane U(1)
gauge field. We relate these results to manifestly supersymmetric approaches to
construction of D-brane actions.Comment: 15 pages; new section and references adde

### p-brane superalgebras via integrability

It has long been appreciated that superalgebras with bosonic and fermionic
generators additional to those in the super-Poincare algebra underlie p-brane
and D-brane actions in superstring theory. These algebras have been revealed
via "bottom up" approaches, involving consideration of Noether charges, and by
"top down" approaches, involving the construction of manifestly supersymmetry
invariant Wess-Zumino actions. In this paper, we give an alternative derivation
of these algebras based on integrability of supersymmetry transformations
assigned to fields in order to solve a cohomology problem related to the
construction of Wess-Zumino terms for p-brane and D-brane actions.Comment: 22 pages, typo corrected, reference adde

### Self-dual supersymmetric nonlinear sigma models

In four-dimensional N=1 Minkowski superspace, general nonlinear sigma models
with four-dimensional target spaces may be realised in term of CCL (chiral and
complex linear) dynamical variables which consist of a chiral scalar, a complex
linear scalar and their conjugate superfields. Here we introduce CCL sigma
models that are invariant under U(1) "duality rotations" exchanging the
dynamical variables and their equations of motion. The Lagrangians of such
sigma models prove to obey a partial differential equation that is analogous to
the self-duality equation obeyed by U(1) duality invariant models for nonlinear
electrodynamics. These sigma models are self-dual under a Legendre
transformation that simultaneously dualises (i) the chiral multiplet into a
complex linear one; and (ii) the complex linear multiplet into a chiral one.
Any CCL sigma model possesses a dual formulation given in terms of two chiral
multiplets. The U(1) duality invariance of the CCL sigma model proves to be
equivalent, in the dual chiral formulation, to a manifest U(1) invariance
rotating the two chiral scalars. Since the target space has a holomorphic
Killing vector, the sigma model possesses a third formulation realised in terms
of a chiral multiplet and a tensor multiplet.
The family of U(1) duality invariant CCL sigma models includes a subset of
N=2 supersymmetric theories. Their target spaces are hyper Kahler manifolds
with a non-zero Killing vector field. In the case that the Killing vector field
is triholomorphic, the sigma model admits a dual formulation in terms of a
self-interacting off-shell N=2 tensor multiplet.
We also identify a subset of CCL sigma models which are in a one-to-one
correspondence with the U(1) duality invariant models for nonlinear
electrodynamics. The target space isometry group for these sigma models
contains a subgroup U(1) x U(1).Comment: 22 page

### Deriving all p-brane superalgebras via integrability

In previous work we demonstrated that the enlarged super-Poincare algebras
which underlie p-brane and D-brane actions in superstring theory can be
directly determined based on the integrability of supersymmetry transformations
assigned to fields appearing in Wess-Zumino terms. In that work we derived
p-brane superalgebras for p = 2 and 3. Here we extend our previous results and
give a compact expression for superalgebras for all valid p.Comment: 26 pages, table added, typos corrected, a few remarks added for
clarificatio

### A supersymmetric nonlinear sigma model analogue of the ModMax theory

A decade ago, it was shown that associated with any model for $\mathsf{U}(1)$
duality-invariant nonlinear electrodynamics there is a unique $\mathsf{U}(1)$
duality-invariant supersymmetric nonlinear sigma model formulated in terms of
chiral and complex linear superfields. Here we study the ${\cal N}=1$
superconformal $\sigma$-model analogue of the conformal duality-invariant
electrodynamics known as the ModMax theory. We derive its dual formulation in
terms of chiral superfields and show that the target space is a K\"ahler cone
with $\mathsf{U}(1)\times \mathsf{U}(1)$ isometry group.Comment: 8 page

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