About the project

A major challenge in building practical quantum computers lies in performing high-fidelity multi-qubit operations across large-scale systems. The GeQuantumBus project tackles this fundamental limitation by developing new physical mechanisms to enable long-distance coupling between spin qubits in semiconductors.

Our approach explores mesoscopic effects that can mediate interactions over micrometre-scale distances, far beyond the conventional nanometre range. To achieve this, we will fabricate state-of-the-art nanoscale devices using ultra-low-disorder compressively strained germanium epitaxially grown on standard silicon wafers, a material platform pioneered by the project’s Principal Investigator.

While current qubit technologies such as ion traps, superconducting circuits, photonic systems, and semiconductor quantum dots have demonstrated remarkable progress, scalable architectures capable of robust multi-qubit operations remain elusive. GeQuantumBus aims to overcome this barrier by developing a quantum bus based on exchange interactions in semiconductor hole-spin qubits. This approach combines the speed of exchange coupling with the flexibility of non-contact device design, making it highly compatible with existing CMOS fabrication techniques.

By exploiting the unique spin properties of holes in compressively strained germanium on silicon (cs-GoS), the project seeks to demonstrate a new paradigm for spin-based quantum computing, one that supports long-range qubit coupling, enables quantum error correction, and lays the groundwork for scalable 2D quantum processor architectures with millions of qubits integrated on a single silicon chip.