Quantum Computing with Spins in Silicon

We have developed a device architecture that allows for the scalable fabrication of one-dimensional silicon spin qubit arrays [1,2]. Devices fabricated on isotopically enriched ²⁸Si quantum wells allow for high fidelity control of four individually addressable spin qubits. Single qubit gate fidelities exceed 99.9% and we demonstrate ac-driven SWAP gates to transfer spin eigenstates with a fidelity of 98% [3]. The high degree of control offered by the device design allows for the transfer of a single electron across a linear array of nine quantum dots in ~50 ns. With more complex control sequences we perform parallel shuttling of two and three electrons through the array [4]. As a demonstration of automated tuning of dot arrays, we use an image analysis toolbox to automate the calibration of virtual gates in these devices [5].

[1] D. M. Zajac et al., Phys. Rev. Appl. 6, 054013 (2016).
[2] D. M. Zajac et al., Science 359, 439 (2018).
[3] A. J. Sigillito et al., npj Quantum Inf. 5, 110 (2019).
[4] A. R. Mills et al., Nat. Commun. 10, 1063 (2019).
[5] A. R. Mills et al., Appl. Phys. Lett. 115, 113501 (2019).