Because a quantum computer would be capable of power and efficiency far beyond that of any conceivable conventional computer, researchers are attacking from all angles the problems associated with building one. Atoms trapped in small electromagnetic cavities, nuclear-magnetic resonance on large molecules and photons have all been put forth as possible bases for a quantum computer. Rather than being stuck with what nature deals you, this kind of qubit allows quantum circuits to be designed in the same way you would design integrated circuits. With it, you have the ability to create your own 'designer' quantum computation system. A superconductor is a metal that, when cooled to very low temperatures, shows no resistance to the flow of electrical current.
Electrical current can flow forever in a loop made of a superconducting wire.
MRI machines are made of large coils of superconducting wire. By making the coil or loop very small, only the diameter of a human hair, the researchers have proposed that these circulating currents will obey the laws of quantum mechanics. The physics theory called quantum mechanics is based on the observed features of subatomic particles. One of these features is spin, or angular momentum. Similar to a compass, spins align in a magnetic field to be either up or down.