Single electron spins in quantum dots are a strong candidate for quantum computers, owing to their potential for scalable manufacturing. While most recent advances have been in the isolation from electric and magnetic noise sources to enhance spin coherence, a sizable spin-electric coupling will be necessary for spin manipulations. Here, we demonstrate experimentally how to fulfill the trade-off between coherence and controllability at an isotopically-enhanced level and achieve single-qubit gate fidelities above 99.9%. We further reveal that the spin coherence is now limited by charge noise – in contrast to conventional magnetic noise – characterized by a 1/f spectrum. Our work presents a promising route to large-scale spin-qubit systems with fault-tolerant controllability.
Research Area “Creation of an innovative quantum technology platform based on the advanced control of quantum states”
Research Theme “Development of base technologies for spin based quantum computing”
Jun Yoneda, Kenta Takeda, Tomohiro Otsuka, Takashi Nakajima, Matthieu R. Delbecq, Giles Allison, Takumu Honda, Tetsuo Kodera, Shunri Oda, Yusuke Hoshi, Noritaka Usami, Kohei M. Itoh and Seigo Tarucha. “A quantum-dot spin qubit with coherence limited by charge noise and fidelity higher than 99.9%”. Nature Nanotechnology, published online December 18 2017, doi: 10.1038/s41565-017-0014-x.
Seigo Tarucha, Ph.D.
Group Director, Center for Emergent Matter Science, RIKEN
Professor, Department of Applied Physics, University of Tokyo
Green Innovation Group, Department of Innovation Research , JST