(Keynote) Devices Architectures and Technology for Quantum Computing

Abstract

There have been a lot of works on quantum computing hardware using various quantum two-level systems as a basic unit of information, which is called quantum bit (qubit). Especially an electron spin in a Si quantum dot (QD) is a well-defined quantum two-level system characterized by a spin-up and a spin-down state. This is one of the most promising candidates for a qubit, because of its long coherence time. The other advantage is that fabrication technology developed for integrated devices in Si can be applied. Toward Si spin qubits, we study physically-defined Si QD devices fabricated using metal-oxide-semiconductor (MOS) structures. We observe spin-related tunneling phenomena and reduce electron numbers in the QDs down to the few-electron regime. Charge detection of change in number of carriers in the QDs, one by one, has also been successfully demonstrated. These achievements are the important steps for realizing quantum computing devices.