4,604 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
S-Duality for D3-Brane in NS-NS and R-R Backgrounds
We construct the low-energy effective field theory for a D3-brane in constant
R-R 2-form potential background as the S-dual theory of a D3-brane in NS-NS
B-field background. Despite the non-Abelian algebra of the noncommutative U(1)
gauge symmetry, the electromagnetic duality transformation can be carried out
to all orders, and the dual Lagrangian is given in a compact form. The gauge
algebra is found to be a mixture of a deformed area-preserving diffeomorphism
and the usual U(1) gauge symmetry.Comment: 29 pages, minor change
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