Demonstrating entangling gates among qubit pairs in the eight-dot SiMOS array

Demonstrate entangling two-qubit gate operations between qubit pairs within the eight-dot linear array of silicon metal-oxide-semiconductor electron spin qubits fabricated using a 300 mm CMOS-compatible foundry process, in order to verify the double–quantum-dot unit-cell approach that decomposes tuning complexity into N/2 two-qubit cells.

Background

The paper reports the coherent operation of an eight-qubit linear array of silicon spin qubits fabricated in a 300 mm CMOS-compatible process, achieving individual qubit control and coherence characterization across all eight qubits and demonstrating exchange-based two-qubit interactions in one pair.

The control and tuning strategy relies on viewing the system as four double quantum dot (DQD) unit cells, which is proposed to simplify scaling by breaking tuning complexity into pairwise units. However, while exchange interactions and phase calibration are shown for one pair, the authors explicitly state that demonstrating entangling gates among qubit pairs is still pending to validate this unit-cell approach.