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Hole spin qubits in germanium are well suited for fast, electrically driven gates with high fidelity, but scaling to large qubit arrays remains challenging. Here the authors demonstrate a 10-spin qubit array with gate fidelities exceeding 99%, revealing mechanisms for uniform and scalable qubit control.

Spin shuttling is a promising technique for establishing a quantum link between qubit registers and has been studied in several quantum dot qubit platforms. Here the authors realize coherent shuttling of a hole spin qubit in a minimal quantum dot chain in germanium despite strong spin-orbit coupling.

Quantum dot spin qubits in Si can be controlled using micromagnet-based electric-dipole spin resonance, but experiments have been limited to small 1D arrays. Here the authors address qubit control in 2D Si arrays, demonstrating low-frequency control of qubits in a 2 x 2 array using hopping gates.

An efficient control strategy is designed for quantum dot arrays, drawing inspiration from classical semiconductor technology. A two-dimensional array of 16 semiconductor quantum dots is operated using only a few shared control lines.

The authors measure electric and magnetic noise, an important source of decoherence for quantum devices, on hole spin qubit devices in quantum wells in Ge/SiGe heterostructures, revealing a reduced charge noise on devices fabricated on Ge wafers.

A four-qubit quantum processor based on germanium hole spin quantum dots is presented. Universal quantum logic is demonstrated on qubits that are positioned in a two-by-two grid, revealing that spin qubits can be coupled in two dimensions.

Singlet–triplet qubits implemented in a 2 × 4 germanium quantum dot array allow for a quantum circuit that generates and distributes entanglement across the array with a remote Bell state fidelity of 75(2)% between the first and last qubit.

Using germanium quantum dots, a four-qubit processor capable of single-, two-, three-, and four-qubit gates, demonstrated by the creation of four-qubit Greenberger−Horne−Zeilinger states, is the largest yet realized with solid-state electron spins.

The authors achieve gate-controlled proximitization of a quantum dot in a planar germanium heterostructure, an isotopically purifiable group IV material. A patterned Pt germanosilicide superconductor is introduced via a thermally activated reaction.

A cryogenic CMOS control chip operating at 3 K is used to demonstrate coherent control and simple algorithms on silicon qubits operating at 20 mK.

The universal control of six qubits in a ²⁸Si/SiGe quantum dot array is demonstrated, achieving Rabi oscillations for each qubit with visibilities of 93.5–98.0%, implying high readout and initialization fidelities.

Spin qubits are attractive for scalable quantum information, but integrating different classes of two-qubit logic has remained elusive. Here, the SWAP, CPHASE, and CNOT-class two-qubit gates are implemented in a silicon device operating even at temperatures above 1 K.

Germanium is a promising material to build quantum components for scalable quantum information processing. This Review examines progress in materials science and devices that has enabled key building blocks for germanium quantum technology, such as hole-spin qubits and superconductor–semiconductor hybrids.

The difficulty in obtaining a superconducting gap free of subgap states has hindered progress with hybrid superconductor-semiconductor devices in germanium. Here, this challenge is addressed by using a germanosilicide parent superconductor to contact high mobility planar germanium, facilitating scalable quantum information processing.