Fermion transfer by vortex tunneling

We study a Fabry-Perot interferometer made out of magnetic and superconducting regions on the surface state of a 3D topological insulator. In particular we investigate the possibility of transferring a chiral edge Majorana fermion between two counter-propagating edges by the tunneling of two superconducting vortices across the superconducting region. This process is potentially useful for topological charge measurement.