Exchange-only two-qubit operations in a two-dimensional SLEDGE array

Exchange-only (EO) silicon spin qubits are an increasingly promising platform for quantum computation due to their excellent performance metrics. Scaling spin lattices in two dimensions is an essential step towards fault-tolerant quantum computing, and utilizing the single-layer etch-defined gate electrode (SLEDGE) platform [1] in conjunction with multilevel interconnects [2], we recently demonstrated full control of a two-dimensional (2D) spin qubit array. We characterized many EO qubit instantiations over various combinations of triple quantum dots in that 2x3 array and found all of the single-qubit fidelities for all of the benchmarked qubits to be comparable to those in linear geometries [3]. Here, we report on the characterization of two-qubit entanglement operations in a similar 2x3 array using randomized benchmarking, achieving performance on par with prior two-qubit gate fidelities in a linear SLEDGE array [3]. Relative to prior EO two-qubit results, we demonstrate two-qubit gates for various EO qubit instantiations and connectivity, showcasing the reconfigurability of the EO qubit modality and the opportunity to optimize qubit connectivity in such 2D spin lattices in the presence of defects.

 

[1] W. Ha et al., Nano Lett. 22, 1443 (2021)

[2] S. D. Ha et al., PRX Quantum 6, 030327 (2025)

[3] A. Weinstein et al., Nature 615, 817 (2023)