Some remarks on defects and T-duality

Understand

The equations of motion for a conformal field theory in the presence of defect lines can be derived from an action that includes contributions from bibranes.

• For T-dual toroidal compactifications, they imply a direct relation between Poincare line bundles and the action of T-duality on boundary conditions.
• We also exhibit a class of diagonal defects that induce a shift of the B-field.
• We finally study T-dualities for S^1-fibrations in the example of the Wess-Zumino-Witten model on SU(2) and lens spaces.