Casimir Effect for a Semitransparent Wedge and an Annular Piston. (arXiv:0911.1123v1 [hep-th])

We consider the Casimir energy due to a massless scalar field in a geometryof an infinite wedge closed by a Dirichlet circular cylinder, where the wedgeis formed by $\delta$-function potentials, so-called semitransparentboundaries. A finite expression for the Casimir energy corresponding » Full text »