Bound states induced by two impurities in a p-wave superconductor

we study the bound states induced by two nonmagnetic impurities in a p-wave superconductor. The bound state of a single impurity is split into two in the presence two impurities. The resonance energy of the bound state oscillates as the separation between impurities increases and can even cross the Fermi energy at a certain value of the separation and the impurity strength. The induced bound states,can be understood by quantum interference between the quasiparticle wave functions scattered by impurities.