252 research outputs found
Selfduality of non-linear electrodynamics with derivative corrections
In this paper we investigate how electromagnetic duality survives derivative
corrections to classical non-linear electrodynamics. In particular, we
establish that electromagnetic selfduality is satisfied to all orders in
for the four-point function sector of the four dimensional open
string effective action.Comment: 8 page
On the fermionic T-duality of the AdS_4 \times CP^3 sigma-model
In this note we consider a fermionic T-duality of the coset realization of
the type IIA sigma-model on AdS_4 \times CP^3 with respect to the three flat
directions in AdS_4, six of the fermionic coordinates and three of the CP^3
directions. We show that the Buscher procedure fails as it leads to a singular
transformation and discuss the result and its implications.Comment: LaTeX2e, 9 pages, no figures, JHEP style; v2: minor clarifications;
v3: typos fixed, matches the published versio
Towards the String representation of the dual Abelian Higgs model beyond the London limit
We perform a path-integral analysis of the string representation of the dual
Abelian Higgs (DAH) model beyond the London limit, where the string describing
the vortex of a flux tube has a finite thickness. We show that besides an
additional vortex core contribution to the string tension, a modified Yukawa
interaction appears as a boundary contribution in the type-II dual
superconducting vacuum. In the London limit, the modified Yukawa interaction is
reduced to the Yukawa one.Comment: 13 pages, JHEP3.cls is used, no figures. The version accepted for
publication in JHE
Seiberg-Witten-type Maps for Currents and Energy-Momentum Tensors in Noncommutative Gauge Theories
We derive maps relating the currents and energy-momentum tensors in
noncommutative (NC) gauge theories with their commutative equivalents. Some
uses of these maps are discussed. Especially, in NC electrodynamics, we obtain
a generalization of the Lorentz force law. Also, the same map for anomalous
currents relates the Adler-Bell-Jackiw type NC covariant anomaly with the
standard commutative-theory anomaly. For the particular case of two dimensions,
we discuss the implications of these maps for the Sugawara-type energy-momentum
tensor.Comment: 14 pages, JHEP styl
Electric-Magnetic Duality Rotations and Invariance of Actions
For D=4 theories of a single U(1) gauge field strength coupled to gravity and
matters, we show that the electric-magnetic duality can be formulated as an
invariance of the actions. The symmetry is associated with duality rotation
acting directly on the gauge field. The rotation is constructed in flat space,
and an extension to curved spaces is also given. It is non-local and
non-covariant, yet generates off-shell extended transformation of the field
strength. The algebraic condition of Gaillard and Zumino turns out to be a
necessary and sufficient condition for the invariance of actions. It may be
used as a guiding principle in constructing self-dual actions in string and
field theories.Comment: Latex, 15 page
Holography in flat spacetime: 4D theories and electromagnetic duality on the border
We consider a free topological model in 5D euclidean flat spacetime, built
from two rank-2 tensor fields. Despite the fact that the bulk of the model does
not have any particular physical interpretation, on its 4D planar edge
nontrivial gauge field theories are recovered, whose features are entirely
determined by the gauge and discrete symmetries of the bulk. In particular no
4D dynamics can be obtained without imposing a Time Reversal invariance in the
bulk. Remarkably, one of the two possible edge models selected by the Time
Reversal symmetries displays a true electromagnetic duality, which relates
strong and weak coupling regimes. Moreover this same model, when considered
on-shell, coincides with the Maxwell theory, which therefore can be thought of
as a 4D boundary theory of a seemingly harmless 5D topological model.Comment: 21 pages, plain LaTeX, no figures. Version to appear on JHE
Instantons, finite N=2 Sp(N) theories and the AdS/CFT correspondence
We examine ADHM multi-instantons in the conformal N=2 supersymmetric Sp(N)
gauge theory with one anti-symmetric tensor and four fundamental
hypermultiplets. We argue that the ADHM construction and measure can also be
deduced from purely field theoretic considerations and also from the dynamics
of D-instantons in the presence of D3-branes, D7-branes and an orientifold
O7-plane. The measure then admits a large-N saddle-point approximation where
the D3-branes disappear but the background is changed to AdS_5 x S^5/Z_2, as
expected on the basis of the AdS/CFT correspondence. The large-N measure
displays the fractionation of D-instantons at the singularity S^3 in S^5/Z_2
and is described for instanton number k by a certain O(k) matrix model.Comment: 16 pages, jhep.cl
Yangians in Deformed Super Yang-Mills Theories
We discuss the integrability structure of deformed, four-dimensional N=4
super Yang-Mills theories using Yangians. We employ a recent procedure by
Beisert and Roiban that generalizes the beta deformation of Lunin and Maldacena
to produce N=1 superconformal gauge theories, which have the superalgebra
SU(2,2|1)xU(1)xU(1). The deformed theories, including those with the more
general twist, were shown to have retained their integrable structure. Here we
examine the Yangian algebra of these deformed theories. In a five field
subsector, we compute the two cases of SU(2)xU(1)xU(1)xU(1) and
SU(2|1)xU(1)xU(1) as residual symmetries of SU(2,2|1)xU(1)xU(1). We compute a
twisted coproduct for these theories, and show that only for the residual
symmetry do we retain the standard coproduct. The twisted coproduct thus
provides a method for symmetry breaking. However, the full Yangian structure of
SU(2|3) is manifest in our subsector, albeit with twisted coproducts, and
provides for the integrability of the theory.Comment: 17 page
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