Quantum field theory with an interaction on the boundary
  We consider quantum theory of fields \phi defined on a D dimensional manifold (bulk) with an interaction V(\phi) concentrated on a d<D dimensional surface (brane). Such a quantum field theory can be less singular than the one in d dimensions with the interaction $V(\phi)$. It is shown that scaling properties of fields on the brane are different from the ones in the bulk. 
Z. Haba