A recent experiment [Mourik et al., Science 336, 1003 (2012)] on InSb quantum
wires provides possible evidence for the realization of a topological
superconducting phase and the formation of Majorana bound states. Motivated by
this experiment, we consider the signature of Majorana bound states in the
differential tunneling conductance of multi-subband wires. We show that the
weight of the Majorana-induced zero-bias peak is strongly enhanced by mixing of
subbands, when disorder is added to the end of the quantum wire. We also
consider how the topological phase transition is reflected in the gap structure
of the current-voltage characteristic.Comment: 4+ pages, 5 figures, minor changes in the text and Fig. 5, references
added; published versio
