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

Projektinformationen

TopoTapered

ID Finanzhilfevereinbarung: 101067680

DOI

10.3030/101067680

Das Projekt endete am 7 April 2025

EK-Unterschriftsdatum 27 Februar 2023

Startdatum 1 August 2023

Enddatum 31 Juli 2025

Finanziert unter

• European Research Council (ERC)

Gesamtkosten

Keine Daten

EU-Beitrag

€ 150 000,00

Koordiniert durch

WEIZMANN INSTITUTE OF SCIENCE
Israel

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

Berichtszeitraum: 2023-08-01 bis 2025-07-31

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

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.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

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.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

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.

picture1.png