260 research outputs found
Dual theories for mixed symmetry fields. Spin-two case: (1,1) versus (2,1) Young symmetry type fields
We show that the parent Lagrangian method gives a natural generalization of
the dual theories concept for non p-form fields. Using this generalization we
construct here a three-parameter family of Lagrangians that are dual to the
Fierz-Pauli description of a free massive spin-two system. The dual field is a
three-index tensor T, which dinamically belongs to the (2,1) representation of
the Lorentz group. As expected, the massless limit of our Lagrangian, which is
parameter independent, has two propagating degrees of freedom per space point.Comment: 10 pages, no figure
On the Class of Possible Nonlocal Anyon-Like Operators and Quantum Groups
We find a class of nonlocal operators constructed by attaching a disorder
operator to fermionic degrees of freedom, which can be used to generate
q-deformed algebras following the Schwinger approach. This class includes the
recently proposed anyonic operators defined on a lattice.Comment: 10 pages (plain latex), HU-SEFT R 1993-9, to be published in Journal
of Physics A: Math. and General, Letters to the Edito
Charges and fluxes in Maxwell theory on compact manifolds with boundary
We investigate the charges and fluxes that can occur in higher-order Abelian
gauge theories defined on compact space-time manifolds with boundary. The
boundary is necessary to supply a destination to the electric lines of force
emanating from brane sources, thus allowing non-zero net electric charges, but
it also introduces new types of electric and magnetic flux. The resulting
structure of currents, charges, and fluxes is studied and expressed in the
language of relative homology and de Rham cohomology and the corresponding
abelian groups. These can be organised in terms of a pair of exact sequences
related by the Poincar\'e-Lefschetz isomorphism and by a weaker flip symmetry
exchanging the ends of the sequences. It is shown how all this structure is
brought into play by the imposition of the appropriately generalised Maxwell's
equations. The requirement that these equations be integrable restricts the
world-volume of a permitted brane (assumed closed) to be homologous to a cycle
on the boundary of space-time. All electric charges and magnetic fluxes are
quantised and satisfy the Dirac quantisation condition. But through some
boundary cycles there may be unquantised electric fluxes associated with
quantised magnetic fluxes and so dyonic in nature.Comment: 28 pages, plain Te
Introduction to Magnetic Monopoles
One of the most basic properties of magnetism is that a magnet always has two
poles, north and south, which cannot be separated into isolated poles, i.e.,
magnetic monopoles. However, there are strong theoretical arguments why
magnetic monopoles should exist. In spite of extensive searches they have not
been found, but they have nevertheless played a central role in our
understanding of physics at the most fundamental level.Comment: 22 pages, 7 figures. To be published in Contemporary Physic
Confinement from new global defect structures
We investigate confinement from new global defect structures in three spatial
dimensions. The global defects arise in models described by a single real
scalar field, governed by special scalar potentials. They appear as
electrically, magnetically or dyonically charged structures. We show that they
induce confinement, when they are solutions of effective QCD-like field
theories in which the vacua are regarded as color dielectric media with an
anti-screening property. As expected, in three spatial dimensions the
monopole-like global defects generate the Coulomb potential as part of several
confining potentials.Comment: RevTex4, 7 pages, 1 figure. Version to appear in Eur. Phys. J.
Gravito-electromagnetism
We develop and apply a fully covariant 1+3 electromagnetic analogy for
gravity. The free gravitational field is covariantly characterized by the Weyl
gravito-electric and gravito-magnetic spatial tensor fields, whose dynamical
equations are the Bianchi identities. Using a covariant generalization of
spatial vector algebra and calculus to spatial tensor fields, we exhibit the
covariant analogy between the tensor Bianchi equations and the vector Maxwell
equations. We identify gravitational source terms, couplings and potentials
with and without electromagnetic analogues. The nonlinear vacuum Bianchi
equations are shown to be invariant under covariant spatial duality rotation of
the gravito-electric and gravito-magnetic tensor fields. We construct the
super-energy density and super-Poynting vector of the gravitational field as
natural U(1) group invariants, and derive their super-energy conservation
equation. A covariant approach to gravito-electric/magnetic monopoles is also
presented.Comment: 14 pages. Version to appear in Class. Quant. Gra
Evidence for Non-perturbative String Symmetries
String theory appears to admit a group of discrete field transformations --
called dualities -- as exact non-perturbative quantum symmetries.
Mathematically, they are rather analogous to the better-known duality
symmetries, which hold perturbatively. In this talk the evidence for
duality is reviewed and some speculations are presented.Comment: Error corrected and reference added; 10 pages, latex, no figures,
conference Repor
Bags, junctions, and networks of BPS and non-BPS defects
We investigate several models of coupled scalar fields that present discrete
Z_2, Z_2 x Z_2, Z_3 and other symmetries. These models support topological
domain wall solutions of the BPS and non-BPS type. The BPS solutions are
stable, but the stability of the non-BPS solutions may depend on the parameters
that specify the models. The BPS and non-BPS states give rise to bags, and also
to three-junctions that may allow the presence of networks of topological
defects. In particular, we show that the non-BPS defects of a specific model
that engenders the Z_3 symmetry give rise to a stable regular hexagonal network
of domain walls.Comment: Revtex, 16 pages, 6 ps figures; Shorter version to be published in
Phys. Rev.
Some properties of unstable monopoles in Super-QCD
We study embeddings of the Prasad-Sommerfield monopole solution in SU(N)
Super-QCD (N>2), where the role of the Higgs field is played by the squarks in
the fundamental representation. Classically, the resulting configurations live
in a phase with unbroken SU(k) subgroups of SU(N) (as a result they are not
topologically stable). The structure of zero modes is such that they can be
naturally interpreted as massive chiral superfields with R charge one and
baryon number zero, transforming in the adjoint representation of a dual gauge
group defined using the Goddard-Nuyts-Olive (GNO) framework. We discuss the
possible applications of these monopoles to N=1 duality, and more generally the
possibility of relating GNO-type dual gauge groups to those appearing in N=1
duality.Comment: 15 pages. harvma
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