The germanium quantum information route
Résumé
In the worldwide endeavor for disruptive quantum technologies, germanium is emerging as a versatile material to realize
devices capable of encoding, processing, or transmitting quantum information. These devices leverage special properties of
the germanium valence-band states, commonly known as “holes”, such as their inherently strong spin-orbit coupling and the
ability to host superconducting pairing correlations. In this Review, we initially introduce the physics of holes in low-dimensional
germanium structures with key insights from a theoretical perspective. We then examine the material science progress
underpinning germanium-based planar heterostructures and nanowires. We review the most significant experimental results
demonstrating key building blocks for quantum technology, such as an electrically driven universal quantum gate set with spin
qubits in quantum dots and superconductor-semiconductor devices for hybrid quantum systems. We conclude by identifying
the most promising prospects toward scalable quantum information processing.