Abstracts
Branislav Sazdovic
Tduality and nongeometry
The role of double space is essential in new interpretation of Tduality and consequently in an attempt to construct Mtheory. The case of open string is missing in such approach because until now there has been no appropriate formulation of open string Tduality. We will consider here reconsideration of Tduality of the open string. This will allow us to introduce some geometric features in nongeometric theories.
First, we will show that "restricted general coordinate transformations", which includes transformations of background fields but not include transformations of the coordinates, is the symmetry Tdual to the local gauge transformations. This will enable us to introduced new (up to now missing) term in the Lagrangian, with additional gauge field A^D_i (D denotes components with Dirichlet boundary conditions). It compensates nonfulfilment of the invariance under restricted general coordinate transformation on the endpoints of open string, as well as standard gauge field A^N_a (N denotes components with Neumann boundary conditions) compensates nonfulfilment of the local gauge invariance on the endpoints of open string. Using generalized procedure we will perform Tduality of vector fields linear in coordinates. We show that gauge fields A^N_a and A^D_i are Tdual to *A_D^a and *A_N^i respectively. Finally, we proved that all above results can be interpreted as coordinate permutations in double space.
We introduce the field strength of Tdual nongeometric theories as derivative of Tdual gauge fields along both Tdual variable y_\mu and its double {\tilde y}_\mu. This definition allows us to obtain gauge transformation of nongeometric theories which leaves Tdual field strength invariant. Therefore, we introduce some new features of nongeometric theories where field strength has both antisymmetric and symmetric parts. This allows us to define new kind of truly nongeometric theories.
