Topological rf SQUID with a frustrating π junction for probing the Majorana bound state

Majorana bound states are predicted to appear as boundary states of the Kitaev model. Here we show that a π-Josephson junction, inserted in a topologically nontrivial model ring, sustains a Majorana bound state, which is robust with respect to local and nonlocal perturbations. The realistic structure could be based on a high-Tc superconductor tricrystal structure, similar to the one used to spot the d-wave order parameter. The presence of the Majorana bound state changes the ground state of the topologically nontrivial ring in a measurable way with respect to that of a conventional one.