Quantum dot-based quantum information devices

Abstract

Electron spin confined to quantum dots has a long decoherence time and very small physical size as a quantum information medium, and active research directed at constructing large-scale quantum computing has recently been accelerating. Here I review the current status and outlook for multiple qubits and high-fidelity quantum operations, both which are challenges in terms of constructing spin-based quantum computers. Quantum information devices with electron spin have mainly been studied for GaAs dots to date, but more recently have included Si dots because Si is advantageous for making integrated circuits and is the least affected by decoherence. I will first describe our approaches for increasing the qubit number and reducing decoherence with GaAs quantum dots and then those for raising quantum gate fidelity with Si/SiGe quantum dots.