2,525 research outputs found
Stable p-branes in Chern-Simons AdS supergravities
We construct static codimension-two branes in any odd dimension D, with
negative cosmological constant, and show that they are exact solutions of
Chern-Simons (super)gravity theory for (super)AdS coupled to external sources.
The stability of these solutions is analyzed by counting the number of
preserved supersymmetries. It is shown that static massive (D-3)-branes are
unstable unless some suitable gauge fields are added and the brane is extremal.
In particular, in three dimensions, a 0-brane is recognized as the negative
mass counterpart of the BTZ black hole. For these 0-branes, we write explicitly
electromagnetically charged BPS states with various number of preserved
supersymmetries within the OSp(p|2) x OSp(q|2) supergroups. In five dimensions,
we prove that stable 2-branes with electromagnetic charge always exist for the
generic supergroup SU(2,2|N), where N is different than 4. For the special case
N=4, in which the CS supergravity requires the addition of a nontrivial gauge
field configuration in order to preserve maximal number of degrees of freedom,
we show for two different static 2-branes that they are BPS states (one of
which is the ground state), and from the corresponding algebra of charges we
show that the energy is bounded from below. In higher dimensions, our results
admit a straightforward generalization, although there are presumably more
solutions corresponding to different intersections of the elementary objects.Comment: 43 pages, revtex4.cls; v2: slight amendments and references added to
match published versio
Extended Charged Events and Chern-Simons Couplings
Recently, the concept of dynamical extended charged events has been
introduced, and it has been argued that they should play as central a role as
that played by particles or ordinary branes. In this article we show that in
the presence of a Chern-Simons coupling, a magnetically charged extended event
emits an extended object, which geometrically is just like a Dirac string, but
it is observable, obeys equations of motion, and may be electrically charged.
We write a complete action principle which accounts for this effect. The action
involves two Chern-Simons terms, one integrated over spacetime and the other
integrated over the worldvolume of the submanifold that is the union of the
Dirac world-sheet and the history of the emitted physical object. By demanding
that the total charge emitted by a composite extended magnetic event be
quantized according to Dirac's rule, we find a quantization condition for the
Chern-Simons coupling. For a 1-form electric potential in D=2n+1 spacetime
dimensions, the composite event is formed by n elementary extended magnetic
events separated in time such that the product of their transverse spaces,
together with the time axis, is the entire spacetime. We show that the emitted
electric charge is given by the integral of the (n-1)-th exterior power of the
electromagnetic field strength over the last elementary event, or,
equivalently, over an appropriate closed surface. The extension to more general
p-form potentials and higher dimensions is also discussed. For the case D=11,
p=3, our result for the quantization of the Chern-Simons coupling was obtained
previously in the context of M-theory, a remarkable agreement that makes the
existence of events even more compelling
Self-dual solitons in N=2 supersymmetric semilocal Chern-Simons theory
We embed the semilocal Chern-Simons-Higgs theory into an N=2 supersymmetric
system. We construct the corresponding conserved supercharges and derive the
Bogomol'nyi equations of the model from supersymmetry considerations. We show
that these equations hold provided certain conditions on the coupling constants
as well as on the Higgs potential of the system, which are a consequence of the
huge symmetry of the theory, are satisfied. They admit string-like solutions
which break one half of the supersymmetries --BPS Chern-Simons semilocal cosmic
strings-- whose magnetic flux is concentrated at the center of the vortex. We
study such solutions and show that their stability is provided by supersymmetry
through the existence of a lower bound for the energy, even though the manifold
of the Higgs vacuum does not contain non-contractible loops.Comment: 12 pages, LaTeX, no figures, to appear in Modern Physics Letters
Effective Superpotentials for SO/Sp with Flavor from Matrix Models
We study matrix models related to gauge theories with flavors. We
give the effective superpotentials for gauge theories with arbitrary tree level
superpotential up to first instanton level. For quartic tree level
superpotential we obtained exact one-cut solution. We also derive
Seiberg-Witten curve for these gauge theories from matrix model argument.Comment: 17pp,2 figures, v2;refs added and to appear in MPL
A topological bound for electroweak vortices from supersymmetry
We study the connection between N=2 supersymmetry and a topological bound in a two-Higgs doublet system having an SU(2)\times U(1)_Y\times U(1)_{Y^{\prime}} gauge group. We derive Bogomol'nyi equations from supersymmetry considerations showing that they hold provided certain conditions on the coupling constants, which are a consequence of the huge symmetry of the theory, are satisfied. Certain interesting limiting cases of our model are analysed
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