Asia Pacific Physics Week 2023 (APPW2023)

Tuesday, Nov. 7, 2023 

2:00 PM - 2:40 PM  Plenary Talk  Akira Oiwa (Osaka University) 

Semiconductor spin qubits for quantum networking

  Akira Oiwa 1,2,3

1 SANKEN, Osaka University, Osaka, Japan

2 Center for Quantum Information and Quantum Biology, Osaka University, Osaka, Japan

3 Spintronics Research Network Division, OTRI, Osaka University, Osaka, Japan

Semiconductor spin qubits are well recognized as a promising platform for scalable fault-tolerant quantum computers (FTQCs) because of relatively long spin coherence time in solid state devices and high-electrical tuneability of the quantum states [1]. In addition, semiconductors have a great potential for applications in quantum communications because of their abilities in optical devices. Therefore, especially in the quantum repeater applications, the semiconductor spin qubits provide the ways to efficiently connect qubit modules or quantum computers via optical fiber and construct the global quantum networks, contributing to realize secure quantum communications and distributed quantum computing [2].

In this talk, we present the physical process and its demonstration of the quantum state conversion from single photon polarization states to single electron spin states in gate-defined quantum dots (QDs) [3]. As significant achievements, we show that the enhancement of the conversion efficiency from a single photon to a single spin in a quantum dot using photonic nanostructures [4]. Finally, we discuss a blueprint of high conversion efficiency quantum repeater operating directly at a telecom wavelength based on semiconductor spin qubits.

This work is supported by JST Moonshot R&D Grant No. JPMJMS2066-31 and JPMJMS226B; Grant-in-Aid Scientific Research (S), 23H05458, QSP-013 NRC, Canada.

[1] G. Burkard et al., Rev. Mod. Phys. 95, 025003 (2023).

[2] A. Oiwa et al., J. Phys. Soc. Jpn. 86, 011008 (2017); L. Gaudreau et al., Semicond. Sci. Technol. 32, 093001 (2017).

[3] T. Fujita et al., Nature commun. 10, 2991 (2019); K. Kuroyama et al., Phys. Rev. B 10, 2991 (2019).

[4] R. Fukai et al., Appl. Phys. Express 14, 125001 (2021); S. Ji et al., Jpn. J. Appl. Phys. 62, SC1018 (2023).