A "spins-inside" quantum processor
The canonical two-level quantum system, a single electron spin in a magnetic field, is gaining ground as a scalable and long-lived qubit system. In our work, we confine individual electrons in gate-defined semiconductor quantum dots, and control and read out the spin states all-electrically. We are currently measuring arrays with up to four quantum dots in a design that is easily extendable along one dimension. In parallel, we are exploring avenues for creating 2D networks of spin qubits, as required in for practical fault-tolerance. Increasingly, we make use of (isotopically purified) silicon instead of GaAs as the quantum dot host material, as this offers up to four orders of magnitude improvements in dephasing and coherence times. Through these advances, the feeling grows that a large-scale quantum computer can actually be built, and we have recently engaged in an intensive, long-term collaboration with Intel to make it happen.