Seigo Tarucha

Silicon is a promising platform for making spin qubits in quantum computing, because of the long intrinsic coherence time and compatibility with advanced semiconductor manufacturing technology. Taking these advantages high-fidelity quantum operations have been achieved and industrial approaches have been employed to fabricate multi-qubit devices. In this talk I will review updated development of high control fidelities of single- and two-qubit gates [1, 2]. Based on the results of the two-qubit experiments we have developed three qubit operations necessary for implementing quantum error correction, including generation of a three-spin entangled state [3] and a Toffoli gate, and finally achieved the three qubit phase error correction [4]. Lastly I will discuss the charge noise effects to influence the qubit fidelity in multi-qubit devices. We observe a strong noise correlation between qubits, which may influence the performance of multi-qubit entanglement as well as quantum error correction.

[1] J. Yoneda et al., Nature Nanotechnol. 13, 102 (2018).
[2] A. Noiri et al., Nature 601, 338 (2022).
[3] K. Takeda et al. Nature Nanotechnol. 16, 965 (2021).
[4] K. Takeda et al. Nature 608, 882 (2022).
[5] J. Yoneda et al. arXiv: 2208.14150.