52,977 research outputs found
3-Point Functions in N=4 Yang-Mills
Three-point functions of analytic (chiral primary) operators in N=4
Yang-Mills theory in four dimensions are calculated using the harmonic
superspace formulation of this theory. In the case of the energy-momentum
tensor multiplet anomaly considerations determine the coefficient. Analyticity
in N=2 harmonic superspace is explicitly checked in a two-loop calculation.Comment: This file requires the feynman.tex macro Some references are adde
The Six Dimensional Self-Dual Tensor
The equations of motion for a self-interacting self-dual tensor in six
dimensions are extracted from the equations describing the M-theory five-brane.
These equations are presented in a self-contained, six-dimensional
Lorentz-covariant form. In particular, it is shown that the field-strength
tensor satisfies a non-linear generalised self-duality constraint. The
self-duality equation is rewritten in five-dimensional notation and shown to be
identical to the corresponding equation in the non-covariant formalism.Comment: 8 pages, late
Superconformal Invariants and Extended Supersymmetry
The superconformal invariants in analytic superspace are found.
Superconformal invariance is shown to imply that the Green's functions of
analytic operators are invariant holomorphic sections of a line bundle on a
product of certain harmonic superspaces. It is argued that the correlation
functions for a class of sufficiently low dimension gauge invariant operators
in N=2 and N=4 supersymmetric Yang-Mills theory can be evaluated up to
constants.Comment: 10p, late
A note on the UV behaviour of maximally supersymmetric Yang-Mills theories
The question of whether BPS invariants are protected in maximally
supersymmetric Yang-Mills theories is investigated from the point of view of
algebraic renormalisation theory. The protected invariants are those whose
cohomology type differs from that of the action. It is confirmed that one-half
BPS invariants () are indeed protected while the double-trace one-quarter
BPS invariant () is not protected at two loops in D=7, but is protected
at three loops in D=6 in agreement with recent calculations. Non-BPS
invariants, i.e. full superspace integrals, are also shown to be unprotected.Comment: 12 pages. Minor changes to text. References adde
Strings and D-Branes with Boundaries
The covariant field equations of ten-dimensional super D-branes are obtained
by considering fundamental strings whose ends lie in the superworldsurface of
the D-brane. By considering in a similar fashion Dp-branes ending on
D(p+2)-branes we derive equations describing D-branes with dual potentials, as
well as the vector potentials.Comment: 12 pages, Late
Supersymmetry counterterms revisited
Superspace power-counting rules give estimates for the loop order at which
divergences can first appear in non-renormalisable supersymmetric field
theories. In some cases these estimates can be improved if harmonic superspace,
rather than ordinary superspace, is used. The new estimates are in agreement
with recent results derived from unitarity calculations for maximally
supersymmetric Yang-Mills theories in five and six dimensions. For N=8
supergravity in four dimensions, we speculate that the onset of divergences may
correspondingly occur at the six loop order.Comment: 10 pages, plain Late
Quantizing the (0,4) Supersymmetric ADHM Sigma Model
We discuss the quantization of the ADHM sigma model. We show that the only
quantum contributions to the effective theory come from the chiral anomalies
and compute the first and second order terms. Finally the limit of vanishing
instanton size is discussed.Comment: 19 pages phyzzx. Expanded discussion of various point and some minor
correction
Monopole Dynamics from the M-Fivebrane
We study the BPS states of the M-fivebrane which correspond to monopoles of
N=2 SU(2) gauge theory. Far away from the centres of the monopoles these states
may be viewed as solitons in the Seiberg-Witten effective action. It is argued
that these solutions are smooth and some properties of their moduli space are
discussed.Comment: 30 pages phyzzx. Paragraph added to the introduction and some minor
corrections. To appear in Nucl. Phys.
Twistor spaces for HKT manifolds
We construct the twistor space associated with an HKT manifold, that is, a
hyper-K\"ahler manifold with torsion, a type of geometry that arises as the
target space geometry in two-dimensional sigma models with (4,0) supersymmetry.
We show that this twistor space has a natural complex structure and is a
holomorphic fibre bundle over the complex projective line with fibre the
associated HKT manifold. We also show how the metric and torsion of the HKT
manifold can be determined from data on the twistor space by a reconstruction
theorem. We give a geometric description of the sigma model (4,0) superfields
as holomorphic maps (suitably understood) from a twistorial extension of (4,0)
superspace (harmonic superspace) into the twistor space of the sigma model
target manifold and write an action for the sigma model in terms of these (4,0)
superfields.Comment: 15 pages, Phyzz
Brane Rotating Symmetries and the Fivebrane Equations of Motion
We show that the fully covariant equations of motion for the M-theory
fivebrane can be interpreted as charge conservation equations. The associated
charges induce `shift'-symmetries of the scalar, spinor and gauge-fields of the
fivebrane, so allowing an interpretation of all these fields as Goldstone
fields. We also find that the fivebrane possesses a new symmetry that is part
of the GL(32) automorphism group of the eleven dimensional supersymmetry
algebra.Comment: 15 pages, late
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