丁香园AV

Synopsis

When a gas of atoms is cooled, at some point it stops behaving like a classical gas, and quantum mechanical properties emerge. The extreme limit of this is when gases of bosonic atoms near absolute zero temperature become cold and dense enough to collapse into a single quantum state. The resulting state, a Bose-Einstein condensate, is a phase of matter that represents the coldest object in the universe. I will describe what BECs are; how we make and study ultra-cold gases in the lab; and discuss some applications of them.