The next steps are clear. First, we need to integrate all of the basic functions into a single system. Then we need to expand the system from two quantum dots to a large array of dots.
And we need to find better ways of overcoming the environment’s effects on the fragile spin states—the most fundamental challenge we researchers face now. One possibility is to construct the quantum-computing chip out of materials that have no nuclear spin, such as isotopically pure silicon‑28 or carbon-12. Eventually we’ll need to reduce the number of errors to at most one in every 10 000 elementary operations. At that point, we could use a technique called quantum error correction to guarantee reliable calculations.
Research paper abstract: Spins in few-electron quantum dots
51 page pdf of the above paper
The Delft spin qubit research home page