Examples of superconducting-silicon quantum devices. (left) A superconducting loop interrupted at two points by junctions can form a superconducting flux qubit or a superconducting quantum interference device, or SQUID. Currents flowing in the loop can be used to measure the strength of a magnetic field threading the loop. The currents (flowing in either direction) can also be used to constitute a qubit. (middle) Separating the superconducting wires by an insulator, in this case pure, crystalline silicon, forms a Josephson junction. (right) Precisely placed, highly doped regions within the semiconductor form the superconducting wires.