Perspective on Majorana bound-states in hybrid superconductor-semiconductor nanowires

Abstract: Topological quantum computing and Majorana bound states were initially theorized between 2000 and 2010. These concepts gradually transitioned to practical implementations during the subsequent decade (2010-2020). Various directions have been investigated with mixed success. With respect to hybrid superconductor-semiconductor devices, great progress has been achieved in the larger area of mesoscopic superconductivity. Firm evidence for a topological phase in hybrid 1D nanowires, however, has not been demonstrated. Now, in the third decade, the lack of definitive topological results prompts a reevaluation. As an active participant, I have witnessed phases of hope, exuberance, and a return to realism and taking a step back. This Perspective provides a personal account of the past decade, my view on the current situation and challenges ahead. I assume the reader is familiar with the subject at the level of, e.g. the review by Prada et al. [1] from which I repeat as little as possible and refer to the extensive reference list for a comprehensive overview. The purpose of this Perspective is to share personal experiences and motivations.