  We propose an implementation for quantum logic and computing using trapped
atomic spins of two different species, interacting via direct magnetic
spin-spin interaction. In this scheme, the spins (electronic or nuclear) of
distantly spaced trapped neutral atoms serve as the qubit arrays for quantum
information processing and storage, and the controlled interaction between two
spins, as required for universal quantum computing, is implemented in a three
step process that involves state swapping with a movable auxiliary spin.
