Atoms, of course, cannot talk. But they can react to each other. This applies in particular to magnetic atoms.
Each such atom carries a small magnetic moment called a spin. These rotations affect each other, like the arrows of a compass, when you bring them closer to each other. If you give one of them a push, they will begin to move together in a very specific way. But, according to the laws of quantum mechanics, each spin can be simultaneously directed in different directions, forming a superposition. This means that the actual transfer of quantum information occurs between atoms, like some kind of conversation.
On a large scale, this exchange of information between atoms can lead to other unusual phenomena. A classic example is superconductivity: the effect in which some materials lose all electrical resistance below a critical temperature. Scientists can explain what happens in the simplest cases, but it is not known how this effect occurs in complex materials.
In the new work, the authors placed two atoms next to each other to see what happens. This is possible thanks to the scanning tunneling microscope: a device in which a sharp needle can examine atoms one by one and even rearrange them. The researchers used this device to place two titanium atoms just over one nanometer apart. At this distance, the atoms are able to detect each other’s spin.
They then quickly flipped the spin of one of the two atoms with a sudden burst of electrical current. To their surprise, this approach led to quantum interactions.
For two atoms together, the new state is a perfect superposition that allows information to be exchanged between each other.