Four-qubit quantum processor in isotopically enriched silicon*

Quantum processors based on spins in semiconductors are rapidly becoming a strong contender in the race to build a quantum computer. When coupled with micromagnets, these devices offer high fidelity single-qubit [1] and two-qubit [2,3] control while maintaining long coherence times. Until now, silicon spin qubit devices incorporating micromagnets have been limited to one and two qubit demonstrations, even though a one-dimensional extended array of silicon quantum dots has been demonstrated [4]. In this presentation, we will present a four-spin-qubit device architecture. This device is fabricated on an isotopically enriched ²⁸Si/SiGe quantum well and offers four individually addressable spin qubits. Multi-qubit gates can be implemented by gating nearest-neighbor exchange interactions. Preliminary data demonstrating single- and multi-qubit operation will be presented.
[1] Yoneda et al., Nat. Nanotech. 13, 102 (2018)
[2] Zajac et al., Science 359, 439 (2018)
[3] Watson et al., Nature 555, 633 (2018)
[4] Zajac et al., Phys. Rev. Applied 6, 054013 (2016)