Milestones toward Majorana-based quantum computing

TL;DR

This paper proposes a comprehensive scheme for creating, controlling, and reading Majorana zero modes in semiconducting wires with superconducting islands, aiming to advance toward topological quantum computing through a series of experimental milestones.

Contribution

It introduces a practical, integrated approach combining materials growth and quantum-dot techniques to achieve milestones from Majorana detection to non-Abelian braiding demonstrations.

Findings

Detection of fusion rules for non-Abelian anyons

Validation of a prototype topological qubit

Demonstration of non-Abelian braiding in a branched geometry

Abstract

We introduce a scheme for preparation, manipulation, and readout of Majorana zero modes in semiconducting wires with mesoscopic superconducting islands. Our approach synthesizes recent advances in materials growth with tools commonly used in quantum-dot experiments, including gate-control of tunnel barriers and Coulomb effects, charge sensing, and charge pumping. We outline a sequence of milestones interpolating between zero-mode detection and quantum computing that includes (1) detection of fusion rules for non-Abelian anyons using either proximal charge sensors or pumped current; (2) validation of a prototype topological qubit; and (3) demonstration of non-Abelian statistics by braiding in a branched geometry. The first two milestones require only a single wire with two islands, and additionally enable sensitive measurements of the system's excitation gap, quasiparticle poisoning rates, residual Majorana zero-mode splittings, and topological-qubit coherence times. These pre-braiding experiments can be adapted to other manipulation and readout schemes as well.