In college, I was amazed to learn that physicists can use lasers and magnets to cool atoms close to absolute zero. In graduate school, I was even more amazed to learn that this can be done in space, aboard the International Space Station.
When some atoms are cooled to ultracold temperatures they behave as quantum mechanical waves. Individual waves can combine to produce one grand quantum wave describing behavior of thousands of atoms.
If the atoms are a type of particle referred to as a boson, this process is a quantum phase transition called Bose-Einstein condensation. The same way water vapor condenses to liquid water when cooled, bosonic atoms condense when made ultracold. They can also form different shapes, like solid spheres and hollow bubbles.
On Earth, gravity is a big obstacle to cooling atoms. It competes with other forces trying to cool the atoms and hold them in place. But this doesn't happen on the ISS. In May of 2018, the Cold Atom Lab was launched onto the ISS and has since successfully produced Bose-Einstein condensates (BECs) in space. A new report outlines how this instrument, installed by astronauts, has shown that BECs made in ISS’s microgravity have some novel features. For example, they can be three times as large as their terrestrial counterparts!
My research relates to experiments that will also take advantage of microgravity. In my doctoral work, I was interested in BECs that form hollow bubbles or shells. On Earth, gravity pulls the atoms from the tops of BECs towards their bottoms, creating a shape more like a salad bowl than a closed bubble. This should not be an issue on the International Space Station where this pull is weak. But does the shape of these molecules matter in quantum physics? Theoretical work by me and my collaborators shows that it does, and experiments in space should give us the answer.