12,048 research outputs found
Special geometry in hypermultiplets
We give a detailed analysis of pairs of vector and hypermultiplet theories
with N=2 supersymmetry in four spacetime dimensions that are related by the
(classical) mirror map. The symplectic reparametrizations of the special
K\"ahler space associated with the vector multiplets induce corresponding
transformations on the hypermultiplets. We construct the Sp(1)Sp()
one-forms in terms of which the hypermultiplet couplings are encoded and
exhibit their behaviour under symplectic reparametrizations. Both vector and
hypermultiplet theories allow vectorial central charges in the supersymmetry
algebra associated with integrals over the K\"ahler and hyper-K\"ahler forms,
respectively. We show how these charges and the holomorphic BPS mass are
related by the mirror map.Comment: Latex 36 pp. A few minor correction
Generalized gaugings and the field-antifield formalism
We discuss the algebra of general gauge theories that are described by the
embedding tensor formalism. We compare the gauge transformations dependent and
independent of an invariant action, and argue that the generic transformations
lead to an infinitely reducible algebra. We connect the embedding tensor
formalism to the field-antifield (or Batalin-Vilkovisky) formalism, which is
the most general formulation known for general gauge theories and their
quantization. The structure equations of the embedding tensor formalism are
included in the master equation of the field-antifield formalism.Comment: 42 pages; v2: some clarifications and 1 reference added; version to
be published in JHE
T-duality and Actions for Non-BPS D-branes
We employ T-duality to restrict the tachyon dependence of effective actions
for non-BPS D-branes. For the Born-Infeld part the criteria of T-duality and
supersymmetry are satisfied by a simple extension of the D-brane Born-Infeld
action.Comment: Latex, 11 page
Representing uncertainty in continental-scale gridded precipitation fields for agrometeorological modeling
This work proposes a relatively simple methodology for creating ensembles of precipitation inputs that are consistent with the spatial and temporal scale necessary for regional crop modeling. A high-quality reference precipitation dataset [the European Land Data Assimilation System (ELDAS)] was used as a basis to define the uncertainty in an operational precipitation database [the Crop Growth Monitoring System (CGMS)]. The distributions of precipitation residuals (CGMS ¿ ELDAS) were determined for classes of CGMS precipitation and transformed to a Gaussian distribution using normal score transformations. In cases of zero CGMS precipitation, the occurrence of rainfall was controlled by an indicator variable. The resulting normal-score-transformed precipitation residuals appeared to be approximately multivariate Gaussian and exhibited strong spatial correlation; however, temporal correlation was very weak. An ensemble of 100 precipitation realizations was created based on back-transformed spatially correlated Gaussian residuals and indicator realizations. Quantile¿quantile plots of 100 realizations against the ELDAS reference data for selected sites revealed similar distributions (except for the 100th percentile, owing to some large residuals in the realizations). The semivariograms of realizations for sampled days showed considerable variability in the overall variance; the range of the spatial correlation was similar to that of the ELDAS reference dataset. The intermittency characteristics of wet and dry periods were reproduced well for most of the selected sites, but the method failed to reproduce the dry period statistics in semiarid areas (e.g., southern Spain). Finally, a case study demonstrates how rainfall ensembles can be used in operational crop modeling and crop yield forecasting
Geometry of N=4, d=1 nonlinear supermultiplet
We construct the general action for nonlinear supermultiplet
including the most general interaction terms which depend on the arbitrary
function obeying the Laplace equation on . We find the bosonic field
which depends on the components of nonlinear supermultiplet and transforms
as a full time derivative under N=4 supersymmetry. The most general interaction
is generated just by a Fayet-Iliopoulos term built from this auxiliary
component.
Being transformed through a full time derivative under
supersymmetry, this auxiliary component may be dualized into a fourth
scalar field giving rise to a four dimensional sigma-model. We
analyzed the geometry in the bosonic sector and find that it is not a
hyper-K\"ahler one. With a particular choice of the target space metric the
geometry in the bosonic sector coincides with the one which appears in
heterotic sigma-model in .Comment: 9 pages, LaTeX file, PACS: 11.30.Pb, 03.65.-
On brane solutions in M(atrix) theory
In this paper we consider brane solutions of the form in M(atrix)
theory, showing the emergence of world volume coordinates for the cases where
. We examine a particular solution with a world volume geometry of the
form in some detail and show how a smooth manifold
structure emerges in the large limit. In this limit the solution becomes
static; it is not supersymmetric but is part of a supersymmetric set of
configurations. Supersymmetry in small locally flat regions can be obtained,
but this is not globally defined. A general group theoretic analysis of the
previously known spherical membrane solutions is also given.Comment: Plain TeX, 18pages, material in sections 2 and 5 rearranged to
clarify interpretatio
Superconformal hypermultiplets
We present theories of N=2 hypermultiplets in four spacetime dimensions that are invariant under rigid or local superconformal symmetries. The target spaces of theories with rigid superconformal invariance are (4n)-dimensional {\it special} hyper-K\"ahler manifolds. Such manifolds can be described as cones over tri-Sasakian metrics and are locally the product of a flat four-dimensional space and a quaternionic manifold. The latter manifolds appear in the coupling of hypermultiplets to N=2 supergravity. We employ local sections of an Sp bundle in the formulation of the Lagrangian and transformation rules, thus allowing for arbitrary coordinatizations of the hyper-K\"ahler and quaternionic manifolds
Comments on the global constraints in light-cone string and membrane theories
In the light-cone closed string and toroidal membrane theories, we associate
the global constraints with gauge symmetries. In the closed string case, we
show that the physical states defined by the BRS charge satisfy the
level-matching condition. In the toroidal membrane case, we show that the
Faddeev-Popov ghost and anti-ghost corresponding to the global constraints are
essentially free even if we adopt any gauge fixing condition for the local
constraint. We discuss the quantum double-dimensional reduction of the wrapped
supermembrane with the global constraints.Comment: 12 pages, typos corrected, to appear in JHE
Deformations of special geometry: in search of the topological string
The topological string captures certain superstring amplitudes which are also
encoded in the underlying string effective action. However, unlike the
topological string free energy, the effective action that comprises
higher-order derivative couplings is not defined in terms of duality covariant
variables. This puzzle is resolved in the context of real special geometry by
introducing the so-called Hesse potential, which is defined in terms of duality
covariant variables and is related by a Legendre transformation to the function
that encodes the effective action. It is demonstrated that the Hesse potential
contains a unique subsector that possesses all the characteristic properties of
a topological string free energy. Genus contributions are constructed
explicitly for a general class of effective actions associated with a
special-K\"ahler target space and are shown to satisfy the holomorphic anomaly
equation of perturbative type-II topological string theory. This identification
of a topological string free energy from an effective action is primarily based
on conceptual arguments and does not involve any of its more specific
properties. It is fully consistent with known results. A general theorem is
presented that captures some characteristic features of the equivalence, which
demonstrates at the same time that non-holomorphic deformations of special
geometry can be dealt with consistently.Comment: 44 pages, LaTex; v2, v3: minor text improvement
N=2 Rigid Supersymmetry with Gauged Central Charge
We develop a general setting for N=2 rigid supersymmetric field theories with
gauged central charge in harmonic superspace. We consider those N=2 multiplets
which have a finite number of off-shell components and exist off shell owing to
a non-trivial central charge. This class includes, in particular, the
hypermultiplet with central charge and various versions of the vector-tensor
multiplet. For such theories we present a manifestly supersymmetric universal
action. Chern-Simons couplings to an external N=2 super Yang-Mills multiplet
are given, in harmonic superspace, for both the linear and nonlinear
vector-tensor multiplets with gauged central charge. We show how to deduce the
linear version of the vector-tensor multiplet from six dimensions.Comment: 46 pages, latex, no figure
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