Luttinger liquid in contact with a Kramers pair of Majorana bound states

We discuss the signatures of a Kramers pair of Majorana modes formed in a Josephson junction on top of a quantum spin Hall system. We show that, while ignoring interactions on the quantum spin Hall edge allows arbitrary Andreev process in the system, moderate repulsive interactions stabilize Andreev transmission - the hole goes into the opposite lead from where the electron has arrived. We analyze the renormalization group equations and deduce the existence of a non-trivial critical point for sufficiently strong interactions.