Evrim Yazgin
Cosmos science journalist
Physicists have taken the first images of individual atoms interacting with each other, helping to prove theoretical correlations that had never been directly observed.
The findings are published in the Physical Review Letters.
Images of individual atoms have been taken before – but only ever in the context of a crystal-like structure or in strong fields where the atoms cannot move.
The new images begin with a “cloud” of freely moving atoms. The researchers then turn on a mesh of light which briefly “freezes” the atoms. Lasers illuminate the suspended atoms to create a picture of their positions before the atoms go back to what they were doing.
Physicists were able to observe for the first time quantum mechanical interactions between atoms, including those responsible for superconductivity and the wave-like nature of tiny objects.
“We are able to see single atoms in these interesting clouds of atoms and what they are doing in relation to each other, which is beautiful,” says senior author Martin Zwierlein from the Massachusetts Institute of Technology (MIT) in the US.
Zwierlein says that seeing the wave-like nature of the atoms is an important step for experimental physics.
“We understand so much more about the world from this wave-like nature,” Zwierlein says. “But it’s really tough to observe these quantum, wave-like effects. However, in our new microscope, we can visualise this wave directly.”
Zwierlein says previous approaches to study clouds of free moving atoms are “like seeing a cloud in the sky, but not the individual water molecules that make up the cloud”.
The most difficult part was to get light from the atoms without them getting too much energy and leaving their optical lattice cage.
“You can imagine if you took a flamethrower to these atoms, they would not like that,” Zwierlein says. “It’s the first time we do it in-situ, where we can suddenly freeze the motion of the atoms when they’re strongly interacting and see them one after the other. That’s what makes this technique more powerful than what was done before.”
