Identify the topological superconducting order in a multi-band quantum wire

Abstract

How to distinguish the zero-bias peak (ZBP) caused by the Majorana fermions from that by the other effects remains a challenge in detecting the topological order of a quantum wire. In this paper we propose to distinguish the topological superconducting phase from the topologically trivial phase by making a Josephson junction of the quantum wire attached to a side lead and then measuring the tunneling conductance through it as the phase difference across the junction $\phi$ varies. Even if the ZBPs exist in both phases, we can identify the topological superconducting phase by a conductance peak at $\phi=\pi$ and a nearby butterfly pattern.