Probing Majorana edge states with a qubit

A pair of counter-propagating Majorana edge modes can be described by an Ising conformal field theory. These modes appear in a chiral p-wave superconductor or in some superconducting system belonging to the same universality class. We show how a superconducting flux qubit attached to a such system couples to the two chiral edge modes via the disorder field of the Ising model. Thus, measuring the back-action of the edge states on the qubit allows to probe the properties of Majorana edge modes.