Spin-orbit qubit in a semiconductor nanowire

TL;DR

This paper demonstrates a spin-orbit qubit in an InAs nanowire, enabling fast, electrically controlled single-qubit operations with enhanced coherence, paving the way for scalable quantum computing and communication applications.

Contribution

It introduces a novel nanowire-based spin-orbit qubit with fast control and improved coherence, highlighting its potential for scalable quantum technologies.

Findings

Achieved fast qubit rotations using electric fields.

Enhanced coherence via dynamic decoupling techniques.

Demonstrated individual addressability of qubits in nanowires.

Abstract

Motion of electrons can influence their spins through a fundamental effect called spin-orbit interaction. This interaction provides a way to electrically control spins and as such lies at the foundation of spintronics. Even at the level of single electrons, spin-orbit interaction has proven promising for coherent spin rotations. Here we report a spin-orbit quantum bit implemented in an InAs nanowire, where spin-orbit interaction is so strong that spin and motion can no longer be separated. In this regime we realize fast qubit rotations and universal single qubit control using only electric fields. We enhance coherence by dynamically decoupling the qubit from the environment. Our qubits are individually addressable: they are hosted in single-electron quantum dots, each of which has a different Land\'e g-factor. The demonstration of a nanowire qubit opens ways to harness the advantages of nanowires for use in quantum computing. Nanowires can serve as one-dimensional templates for scalable qubit registers. Unique to nanowires is the possibility to easily vary the material even during wire growth. Such flexibility can be used to design wires with suppressed decoherence and push semiconductor qubit fidelities towards error-correction levels. Furthermore, electrical dots can be integrated with optical dots in p-n junction nanowires. The coherence times achieved here are sufficient for the conversion of an electronic qubit into a photon, the flying qubit, for long-distance quantum communication.