Scaling up silicon-based quantum processors

Of all of the qubit modalities being investigated, semiconductor spin qubits most closely resemble conventional transistors, which can be readily mass produced. We are developing two-dimensional spin qubit arrays using industrial-scale fabrication processes [1]. In conventional exchange-only spin qubit demonstrations, quantum gates have been implemented using sequences of individually pulsed pairwise exchange interactions. Alternatively, in more highly connected spin qubit devices [2], multiple exchange interactions can be pulsed simultaneously thereby reducing circuit depths. We demonstrate high-fidelity quantum control of an always-on exchange-only qubit, operated using simultaneous exchange pulses [3]. Extensions of this work may enable more efficient exchange only two-qubit entangling gates as well as the implementation of native i-Toffoli gates in Loss-DiVincenzo single-spin qubits.



References

[1] W. Ha et al., Nano Lett. 22, 1443 (2022).

[2] E. Acuna et al., Phys. Rev. Applied 22, 044057 (2024).

[3] J. D. Broz et al., arXiv:2508.01033 (2025).