14,834 research outputs found
Boundary Conditions and the Generalized Metric Formulation of the Double Sigma Model
Double sigma model with the strong constraints is equivalent to the normal
sigma model by imposing the self-duality relation. The gauge symmetries are the
diffeomorphism and one-form gauge transformation with the strong constraints.
We modify the Dirichlet and Neumann boundary conditions with the fully description from the doubled gauge fields. We perform the one-loop
function for the constant background fields to find low energy effective theory
without using the strong constraints. The low energy theory can also be
invariant as the double sigma model. We use the other one way to
construct different boundary conditions from the projectors. Finally, we
combine the antisymmetric background field with the field strength to redefine
a different generalized metric. We use this generalized metric to
construct a consistent double sigma model with the classical and quantum
equivalence. We show the one-loop function for the constant background
fields and obtain the normal sigma model after integrating out the dual
coordinates.Comment: 32 pages, minor changes, references adde
Geometric Low-Energy Effective Action in a Doubled Spacetime
The ten-dimensional supergravity theory is a geometric low-energy effective
theory and the equations of motion for its fields can be obtained from string
theory by computing functions. With compact dimensions, we can add
to it an geometric structure and construct the
supergravity theory inspired by double field theory through the use of a
suitable commutative star product. The latter implements the weak constraint of
the double field theory on its fields and gauge parameters in order to have a
closed gauge symmetry algebra. The consistency of the action here proposed is
based on the orthogonality of the momenta associated with fields in their
triple star products in the cubic terms defined for . This orthogonality
holds also for an arbitrary number of star products of fields for .
Finally, we extend our analysis to the double sigma model, non-commutative
geometry and open string theory.Comment: 27 pages, minor changes, references adde
Electric-Magnetic Dualities in Non-Abelian and Non-Commutative Gauge Theories
Electric-magnetic dualities are equivalence between strong and weak coupling
constants. A standard example is the exchange of electric and magnetic fields
in an abelian gauge theory. We show three methods to perform electric-magnetic
dualities in the case of the non-commutative gauge theory. The first
method is to use covariant field strengths to be the electric and magnetic
fields. We find an invariant form of an equation of motion after performing the
electric-magnetic duality. The second method is to use the Seiberg-Witten map
to rewrite the non-commutative gauge theory in terms of abelian field
strength. The third method is to use the large Neveu Schwarz-Neveu Schwarz
(NS-NS) background limit (non-commutativity parameter only has one degree of
freedom) to consider the non-commutative gauge theory or D3-brane. In
this limit, we introduce or dualize a new one-form gauge potential to get a
D3-brane in a large Ramond-Ramond (R-R) background via field redefinition. We
also use perturbation to study the equivalence between two D3-brane theories.
Comparison of these methods in the non-commutative gauge theory gives
different physical implications. The comparison reflects the differences
between the non-abelian and non-commutative gauge theories in the
electric-magnetic dualities. For a complete study, we also extend our studies
to the simplest abelian and non-abelian -form gauge theories, and a
non-commutative theory with the non-abelian structure.Comment: 55 pages, minor changes, references adde
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