Superconductive Static Quantum Logic

Superconducting rings with exactly $\Phi _0/2$ magnetic flux threading are analogous of Ising spins having two degenerate states which can be used to store binary information. When brought close these rings interact by means of magnetic coupling. If the interactions are properly tailored, a system of such superconducting rings can accomplish static quantum logic in the sense that the states of the rings interpreted as Boolean variables satisfy the desired logic relations when and only when the whole system is in the ground state. Such static logic is essential to carry out the static quantum computation [1,2].