Researchers at Qutech have introduced a new chip architecture aimed at accelerating the scaling of semiconductor spin qubits. The platform, dubbed Qubit-Array Research Platform for Engineering and Testing (Qarpet), integrates a tiled grid of qubit units in a crossbar layout, enabling hundreds of qubits to be characterized on a single chip under realistic operating conditions. “With such a complex, tightly packed quantum chip, things really start to resemble the traditional semiconductor industry,” says Giordano Scappucci, lead researcher.
The demonstration device fabricated in a germanium/silicon-germanium heterostructure contains a 23 by 23 array of tiles. Each tile integrates two hole-spin qubits and a charge sensor, forming a repeatable unit that can be individually addressed through shared row and column control lines. In total, the chip can host up to 1,058 qubits while requiring just 53 control lines, highlighting the efficiency of the crossbar approach. The architecture reaches a potential density of roughly two million qubits per square millimeter.
Using high-frequency electrical readout, the team characterized a subset of 40 tiles, demonstrating the addressability and tunability of individual tiles. As such, the Qarpet architecture serves as a test vehicle for next-generation materials and automated tuning strategies. Notably, the modular design is compatible with silicon qubits.
