Skip main navigation

The critical nature of isotopic engineering

We visit Professor Itoh again.

Join us as Keio’s Professor Kohei Itoh explains how his team works to control the isotopic concentration in materials to help several research groups around the world improve the quality of their qubits.

Most elements have several different types of nuclei, known as isotopes. For example, silicon, which is a common material for making computer chips, has three common isotopes, known as silicon-28, silicon-29, and silicon-30. Silicon-28 and -30 are “spin zero”, but silicon-29 is “spin one half”, the same as a single electron.

If we want to use the nuclear spin of silicon as a qubit, we can. However, if we are using electrons as qubits, or current or magnetic flux, then isotopes with non-zero nuclear spin can interfere with the electron state and cause decoherence. We would rather have a “quiet” environment, with no nuclear spins, as the base on which to build our quantum circuits. Reducing the presence of nuclei with spin is critical for several different technologies, such as quantum dots, as it helps improve the memory lifetime of a qubit.





This article is from the free online

Understanding Quantum Computers

Created by
FutureLearn - Learning For Life

Reach your personal and professional goals

Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates.

Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas.

Start Learning now