To build a universal quantum computer capable of running these and other quantum algorithms, the first thing you’d need is the basic computing element: the qubit.
These qubits, which can measure in the micrometers, are quantum weirdness writ large: When the state of a flux qubit is in superposition, the current flows in both directions around the loop at the same time.
D-Wave uses qubits based on superconducting loops, although these qubits are wired together to make a computer that operates differently from a universal quantum computer.
To compensate for the corruption of a quantum state-and to keep quantum information intact indefinitely-additional long-lived qubits dedicated to identifying and correcting errors must be incorporated for every qubit dedicated to computation.
Large uniform arrays of silicon quantum dots should be easier to fabricate than arrays of donor qubits, because the qubits and any devices needed to connect them or read their states could be made using today’s chipmaking processes.
Silicon: There are a few options for constructing qubits with silicon.
Similar spin qubits can also be made artificially, by using electrode and semiconductor structures to trap electrons inside quantum dots.