A crossbar chip for benchmarking semiconductor spin qubits

Researchers developed QARPET, a scalable crossbar architecture for characterizing semiconductor spin qubits at scale. Implemented in planar germanium with 1,058 potential qubit sites, the platform enables statistical testing of quantum components at millikelvin temperatures using RF reflectometry. The team demonstrated tile addressability across 40 devices, measured threshold voltages and charge noise distributions, and characterized coherence times for singlet-triplet and single-hole spin qubits. The architecture achieves sublinear scaling of control lines and provides a practical testbed for evaluating qubit uniformity and performance across micrometre-scale arrays.