New advance is step toward quantum computing with neutral atoms

This "quantum square dance" may be useful in quantum computing with neutral atoms. Atoms are loaded into individual sites of a 3D grid of light made with laser beams. Initially all the atoms have the same "spin," as indicated by their consistent color. Then, a radio-frequency field (shown as semi-transparent planes) is applied to flip the spins of atoms in every other site, and the sites are paired up, with one atom of each pair spin up (or 1) and the other spin down (or 0), as indicated by the two different colors. Then, all pairs are merged, which causes the atom partners to swap spins repeatedly. These oscillations have the effect of periodically "entangling" the atom pairs, a quantum phenomenon that links their properties even if they are later physically separated. Illustration: Trey Porto/NIST