Physicists Caught Two Atoms 'Talking' to Each Other Illustration: TU DELFT/SCIXEL A team of physicists in the Netherlands and Germany recently placed a bunch of titanium atoms under a scanning tunneling microscope. Those atoms were in constant, quiet interaction with each other through the directions of their spins. In a clever feat, the researchers were able to home in on a single pair of atoms, zapping one with an electric current in order to flip its spin. They then measured the reaction of its partner. Advertisement When two atoms have spins that are interdependent, they are considered quantumly entangled. That entanglement means that the behavior of one atom has a direct impact on the other, and theory says this should remain true even when they are separated by great distances. In this case, the titanium atoms were a little over a nanometer (a millionth of a millimeter) apart, close enough for the two particles to interact with one another but far enough away that the interaction could be detected by the team’s instruments.