Ultracold atoms is a term used to describe atoms that are maintained at temperatures close to 0 kelvin (absolute zero), where their quantum-mechanical properties become important. In other words, the atoms are so cold that they can no longer be thought of as classical billiard balls. Usually, one finds this term used in research related to the production of Bose-Einstein condensates. Key methods to produce ultracold atoms are laser cooling and evaporative cooling.