Researchers Made Ultracold Quantum Bubbles on the Space Station

The International Space Station has a white, cooler-sized fridge. A $100 million facility known as the Cold Atom Laboratory is located in that heavy box, and it allows an array of atomic physics experiments to be done at freezing temperatures in the zero-g of space. Scientists have created tiny bubbles of extremely cold gas atoms, putting them on the edge of quantum physics territory.

It would have been impossible to do that on Earth because it was only possible in microgravity and at a millionth of a degree above absolute zero. The team of physicists behind the milestone, who are all working remotely, published their new research in the journal Nature last week, showing that they made the ultracold bubbles with an experimental apparatus that beamed lasers into a sealed vacuum chamber. Magnetic fields and radio waves were used to create hollow, egg-shaped blobs. The experiment gives insight into the quantum realm and has applications for other areas of physics.

David Aveline is an author of the study and a member of the collaboration working on the Cold Atom Lab.

Ultracold atoms of gas don't act the way they normally would at room temperature, zipping around their container like tiny billiard balls. As the gas cools, they move slower and slower, but without the sluggish atoms turning into a liquid or solid. When they are chilled close to absolute zero, they begin to clump together and the wavelengths associated with the gas particles get longer and overlap.

The atoms start acting weird. They coalesce into a substance that behaves like particles and waves. The Bose-Einstein condensate, named after the Indian and German physicists from a century ago, is a quantum contradiction and almost like a new state of matter. The ultracold atoms need to be cooled even further to be considered a Bose-Einstein condensate, but they are showing signs of that. The bubbles can be inflated to a size much bigger than the width of a human hair.

We are taking physics effects that normally happen at the scale of atoms, and we are making them happen in objects that are up to a millimeter in size, trying to make quantum mechanics and strange physics behavior visible to the naked.

This research could be used for more than quantum physics. Aveline says that work on ultracold atoms could eventually aid the development of more precise gyroscopes and accelerometers. A bubble of ultracold atoms could provide insight into the expansion of the baby universe in a fraction of a second.