Moving Majorana bound states between distinct helical edges across a quantum point contact

TL;DR

This paper proposes a tunable setup using helical edges of 2D topological insulators to manipulate Majorana bound states, enabling their movement across edges and advancing topological quantum computing.

Contribution

It introduces a novel, highly controllable method to move Majorana states across different edges via a quantum point contact in 2DTI systems.

Findings

Allows movement of Majoranas along a single edge

Enables crossing Majoranas between edges via a quantum point contact

Demonstrates robustness against phase control imperfections

Abstract

Majorana bound states are zero-energy excitations of topological superconductors which obey non-Abelian exchange statistics and are basic building blocks for topological quantum computation. In order to observe and exploit their extraordinary properties, we need to be able to properly manipulate them, for instance, by braiding a couple of them in real space. We propose a setup based on the helical edges of two-dimensional topological insulators (2DTI) which allows for a high degree of tunability by only controlling a handful of superconducting phases. In particular, our setup allows to move the Majoranas along a single edge as well as to move them across two different edges coupled by a quantum point contact. Robustness against non-optimal control of the phases is also discussed. This proposal constitutes an essential step forward towards realizing 2DTI-based architectures capable of performing braiding of Majoranas in a feasible way.