One of the key features of the devices is a two by two quantum dot lattice on a commercial foundry service. The mass production of the array is a key step for improving error correction achitectures in quantum computers.
"What we have shown is that we can realize single electron control in every single one of these quantum dots. This is very important for the development of a qubit, because one of the possible ways of making qubits is to use the spin of a single electron,” said Fabio Ansaloni, a researcher at the centre for Quantum Devices at NBI. “Reaching this goal of controlling the single electrons and doing it in a 2D array of quantum dots was very important for us."
Extending quantum computers processors with 2D quantum dot arrays is key for a more efficient implementation of quantum error correction routines. Quantum error correction will enable future quantum computers to be fault tolerant against individual qubit failures during the computations.
"The original idea was to make an array of spin qubits, get down to single electrons and become able to control them and move them around. In that sense it is really great that Leti was able to deliver the samples we have used, which in turn made it possible for us to attain this result,” said Anasua Chatterjee, assistant professor at NBI.
“A lot of credit goes to the pan-European project consortium, and generous funding from the EU, helping us to move from the level of a single quantum dot with a single electron to having two electrons, and now moving on to the two dimensional arrays. Two dimensional arrays is a really big goal, because that's beginning to look like something you absolutely need to build a quantum computer. So Leti has been involved with a series of projects over the years, which have all contributed to this result."