891 research outputs found
(2,2) Supergravity in the Light-Cone gauge
Starting with the prepotential description of two-dimensional
supergravity we use local supersymmetry transformations to go to light-cone
gauge. We discuss properties of the theory in this gauge and derive Ward
identities for correlation functions defined with respect to the induced
supergravity action.Comment: Latex, 20 pages, 2 figures in separate compressed fil
A Critical Behaviour of Anomalous Currents, Electric-Magnetic Universality and CFT_4
We discuss several aspects of superconformal field theories in four
dimensions (CFT_4), in the context of electric-magnetic duality. We analyse the
behaviour of anomalous currents under RG flow to a conformal fixed point in
N=1, D=4 supersymmetric gauge theories. We prove that the anomalous dimension
of the Konishi current is related to the slope of the beta function at the
critical point. We extend the duality map to the (nonchiral) Konishi current.
As a byproduct we compute the slope of the beta function in the strong coupling
regime. We note that the OPE of with itself does not close, but
mixes with a special additional operator which in general is the
Konishi current. We discuss the implications of this fact in generic
interacting conformal theories. In particular, a SCFT_4 seems to be naturally
equipped with a privileged off-critical deformation and this allows us
to argue that electric-magnetic duality can be extended to a neighborhood of
the critical point. We also stress that in SCFT_4 there are two central
charges, c and c', associated with the stress tensor and ,
respectively; c and c' allow us to count both the vector multiplet and the
matter multiplet effective degrees of freedom of the theory.Comment: harvmac tex, 28 pages, 3 figures. Version to be published in Nucl.
Phys.
Direct Calculation of the Boundary Matrix for the Open Heisenberg Chain
We calculate the boundary matrix for the open antiferromagnetic spin
isotropic Heisenberg chain with boundary magnetic fields. Our approach,
which starts from the model's Bethe Ansatz solution, is an extension of the
Korepin-Andrei-Destri method. Our result agrees with the boundary matrix
for the boundary sine-Gordon model with and with
``fixed'' boundary conditions.Comment: 29 pages, plain TEX, UMTG-17
Effective K\"ahler Potentials
We compute the -loop effective K\"ahler potential in the most general
renormalizable supersymmetric quantum field theory.Comment: 11 pages, Late
The Quantum Geometry of N=(2,2) Non-Linear Sigma-Models
We consider a general N=(2,2) non-linear sigma-model in (2,2) superspace.
Depending on the details of the complex structures involved, an off-shell
description can be given in terms of chiral, twisted chiral and semi-chiral
superfields. Using superspace techniques, we derive the conditions the
potential has to satisfy in order to be ultra-violet finite at one loop. We pay
particular attention to the effects due to the presence of semi-chiral
superfields. A complete description of N=(2,2) strings follows from this.Comment: 9 pages, Late
k-Anomalies and Space-Time Supersymmetry in the Green-Schwarz Heterotic Superstring
The computation of -anomalies in the Green-Schwarz heterotic
superstring sigma-model and the corresponding Wess-Zumino consistency condition
constitute a powerful alternative approach for the derivation of manifestly
supersymmetric string effective actions. With respect to the beta-function
approach this technique presents the advantage that a result which is obtained
with the computation of beta-functions at loops can be obtained through the
calculation of -anomalies at \hbox{} loops. In this paper we
derive by a direct one-loop perturbative computation the -anomaly
associated to the Yang-Mills Chern-Simons threeform and, for the first time,
the one associated to the Lorentz Chern-Simons threeform. Contrary to what is
often stated in the literature we show that the Lorentz -anomaly gets
contributions from the integration over both the fermionic {\it and\/} bosonic
degrees of freedom of the string. A careful analysis of the absolute
coefficients of all these anomalies reveals that they can be absorbed by
setting dH={\alpha'\over4}(\trace F^2-\trace R^2), where is the
string tension, the expected result. We show that this relation ensures also
the absence of gauge and Lorentz anomalies in the sigma-model effective action.
We evidenciate the presence of infrared divergences.Comment: 50 pages, latex (uses equations.sty, feynman.tex and a4.sty),
DFPD/94/TH/4
Planar Gravitational Corrections For Supersymmetric Gauge Theories
In this paper we discuss the contribution of planar diagrams to gravitational
F-terms for N=1 supersymmetric gauge theories admitting a large N description.
We show how the planar diagrams lead to a universal contribution at the
extremum of the glueball superpotential, leaving only the genus one
contributions, as was previously conjectured. We also discuss the physical
meaning of gravitational F-terms.Comment: 20 pages, 4 figure
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