A two-dimensional 10-qubit array in germanium with robust and localised qubit control

TL;DR

This paper reports the creation of a 2D array of 10 germanium-based qubits with high-fidelity, localized control, leveraging material and device advances to enable scalable quantum computing architectures.

Contribution

It demonstrates a scalable 2D germanium qubit array with high-fidelity, localized control, and explores parameter optimization for enhanced qubit manipulation.

Findings

Successful fabrication of a 2D 10-qubit array in germanium.

High-fidelity control of qubits up to four neighbors.

Enhanced electric-dipole spin resonance through gate voltage tuning.

Abstract

Quantum computers require the systematic operation of qubits with high fidelity. For holes in germanium, the spin-orbit interaction allows for \textit{in situ} electric fast and high-fidelity qubit gates. However, the interaction also causes a large qubit variability due to strong g-tensor anisotropy and dependence on the environment. Here, we leverage advances in material growth, device fabrication, and qubit control to realise a two-dimensional 10-spin qubit array, with qubits coupled up to four neighbours that can be controlled with high fidelity. By exploring the large parameter space of gate voltages and quantum dot occupancies, we demonstrate that plunger gate driving in the three-hole occupation enhances electric-dipole spin resonance (EDSR), creating a highly localised qubit drive. Our findings, confirmed with analytical and numerical models, highlight the crucial role of intradot Coulomb interaction and magnetic field direction. Furthermore, the ability to engineer qubits for robust control is a key asset for further scaling.