Physicists build an atom laser that can stay on forever

https://phys.org/news/2022-06-physicists-atom-laser.html

"creating continuous Bose-Einstein Condensate... spread the cooling steps not over time, but in space: we make the atoms move while they progress through consecutive cooling steps. In the end, ultracold atoms arrive at the heart of the experiment, where they can be used to form coherent matter waves in a BEC. But while these atoms are being used, new atoms are already on their way to replenish the BEC. In this way we can keep the process going—essentially forever"