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

TL;DR

This paper reflects on the decade-long pursuit of Majorana bound states in superconductor-semiconductor nanowires, highlighting progress, challenges, and the need for reevaluation in the quest for topological quantum computing.

Contribution

It provides a personal perspective on the developments, setbacks, and future challenges in realizing topological phases in hybrid nanowire systems over the past decade.

Findings

Progress in mesoscopic superconductivity

Lack of definitive topological phase evidence

Need for new approaches and reevaluation

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.