Auto-tuning, manipulation and braiding of topological quantum bits in tapered nanowire networks

Informations projet

TopoTapered

N° de convention de subvention: 101067680

DOI

10.3030/101067680

Projet clôturé le 7 Avril 2025

Date de signature de la CE 27 Février 2023

Date de début 1 Août 2023

Date de fin 31 Juillet 2025

Financé au titre de

• European Research Council (ERC)

Coût total

Aucune donnée

Contribution de l’UE

€ 150 000,00

Coordonné par

WEIZMANN INSTITUTE OF SCIENCE
Israel

Periodic Reporting for period 1 - TopoTapered (Auto-tuning, manipulation and braiding of topological quantum bits in tapered nanowire networks)

Période du rapport: 2023-08-01 au 2025-07-31

Résumé du contexte et des objectifs généraux du projet

The goal of the TopoTapered PoC project was to establish tapered nanowires as a viable, robust technology to auto-tune Majorana zero modes (MZMs), transport, and braid them towards quantum computation. The formation of MZMs in quasi-one dimensional semiconducting nanowires necessitates satisfying multiple conditions: The semiconductor has strong spin-orbit coupling; The chemical potential is tuned sufficiently close to the Kramer’s degeneracy throughout the topological segment (sufficiently low disorder); The induced superconducting gap is larger than the Zeeman gap opened by a properly aligned magnetic field; Spatial manipulation of the MZMs has to be adiabatic to remain in the topological groundstate. Tapered nanowires assist in achieving two of these requirements: Tapering modulates the subband quantization along the nanowires and with it the energy of the Kramer’s degeneracy such that they cross the chemical potential at segments along the nanowire without global fine tuning; Application of a global backgate results in sliding of the induced topological segments enabling continuous adiabatic transportation of the MZMs.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

We have successfully demonstrated the advantage of tapered nanowires in tuning their spectroscopic properties. We have grown tapered nanowires with a diameter that gradually varies along the nanowire axis. We have imaged the quasi-local spectroscopy of the electronic subbands using scanning tunneling microscopy.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

The main challenge towards the implementation of our technology has remained the convincing and robust demonstration of MZMs in such hybrid semiconducting-superconducting nanowire systems, which is a prerequisite for the implementation of tapering.

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