Features of the response of Majorana quasiparticles in superconducting wires (brief review)

Interest in hybrid quasi-one-dimensional systems with an inner semiconducting part coated with a superconductor (the so-called core/shell structure) has been grown in the last decade. Materials with a strong spin–orbit coupling and a large $g$-factor (InAs, InSb) are chosen as semiconductors. Due to the proximity effect, such objects can be considered as superconducting wires, where the existence of Majorana states has been predicted. This review briefly summarizes the current experimental studies aimed at the detection of Majorana quasiparticle excitations in superconducting wires. Furthermore, prospects of using the interference geometry of devices including such wires are discussed. In particular, the coherent transport in a spatially inhomogeneous one-dimensional normal metal/superconductor/normal metal system, where normal metal wires serve as arms of an interference device, which interact with a normal metal contact, has been analyzed theoretically. It has been found that responses of Majorana and Andreev low-energy excitations of the device can be distinguished.