A fault-tolerant addressable spin qubit in a natural silicon quantum dot


Fault-tolerant quantum computing requires high-fidelity qubits.

We speed up the spin rotation by utilizing a micromagnet and realized high-fidelity qubits even in industry-standard natural silicon.


The left picture shows a scanning electron micrograph of the device. A double quantum dot is formed at the position of the small blue circles. We can detect the charge state by monitoring a quantum dot sensor indicated by a large blue circle.

The right graph shows a charge stability diagram. Each quantum dot contains one electron. This state can be used as a qubit state.

We apply microwaves to induce the electron spin resonance. The microwave electric field and the magnetic field created by the micromagnet induce the rotation of the spin.

The left graph shows the two resonance lines corresponding to the two quantum dots.

The right graph shows the characteristic chevron pattern.

Rabi oscillations up to 35MHz are observed in our experiment. The evaluated fidelity is 99.6%. This value is the highest one observed in natural silicon quantum dots.


We realized high-fidelity qubits in natural silicon quantum dots by utilizing a micromagnet.

This result can inspire contributions to quantum computing from industrial communities.


“A fault-tolerant addressable spin qubit in a natural silicon quantum dot”,

Kenta Takeda, Jun Kamioka, Tomohiro Otsuka, Jun Yoneda, Takashi Nakajima, Matthieu R. Delbecq, Shinichi Amaha, Giles Allison, Tetsuo Kodera, Shunri Oda, and Seigo Tarucha,

Science Advances 2, e1600694 (2016), arXiv:1602.07833.