Phys.org September 10, 2021
Researchers in Japan have developed a device consisting of a triple quantum dot on a silicon/silicon–germanium heterostructure and controlled through aluminum gates. Each quantum dot can host one electron, whose spin-up and spin-down states encode a qubit. An on-chip magnet generates a magnetic-field gradient that separates the resonance frequencies of the three qubits, so that they can be individually addressed. They first entangled two of the qubits by implementing a two-qubit gate and then realized three-qubit entanglement by combining the third qubit and the gate. The resulting three-qubit state had a remarkably high state fidelity of 88% and was in an entangled state that could be used for error correction. They plan to demonstrate primitive error correction using the three-qubit device and to fabricate devices with ten or more qubits, then plan to develop 50 to 100 qubits and implement more sophisticated error-correction protocols, paving the way to a large-scale quantum computer within a decade…read more. TECHNICAL ARTICLE
Device and experimental setup. Credit: Nature Nanotechnology volume 16, pages965–969 (2021)Â