Topological superconductor–Luttinger liquid junctions

Experimental evidence was recently obtained for topological superconductivity in spin–orbit coupled nanowires in a magnetic field, proximate to an s-wave superconductor. When only part of the wire contacts the superconductor, a localized Majorana mode exists at the junction between superconducting and normal parts of the nanowire. We consider here the case of a T-junction between the superconductor and two normal nanowires and also the case of a single wire with two (or more) partially filled bands in the normal part. We find that coupling this two-channel Luttinger liquid to the single Majorana mode at the junction produces frustration, leading to a critical point separating phases with perfect Andreev scattering in one channel and perfect normal scattering in the other. (paper)