Scaling up qubits is a necessary step to realize useful systems of quantum computation. Here we demonstrate coherent manipulations of four individual electron spins using a micro-magnet method in a quadruple quantum dot - the largest number of dots used for the single spin control in multiple quantum dots. We observe Rabi oscillations and electron spin resonance (ESR) for each dot and evaluate the spin-electric coupling of the four dots, and finally discuss practical approaches to independently address single spin control in multiple quantum dot systems containing even more quantum dots.
@article{arxiv.1805.06111,
title = {Four single-spin Rabi oscillations in a quadruple quantum dot},
author = {Takumi Ito and Tomohiro Otsuka and Takashi Nakajima and Matthieu R. Delbecq and Shinichi Amaha and Jun Yoneda and Kenta Takeda and Akito Noiri and Giles Allison and Arne Ludwig and Andreas D. Wieck and Seigo Tarucha},
journal= {arXiv preprint arXiv:1805.06111},
year = {2018}
}