Ultracold physics is essentially ultracold atoms that are present at temperatures close to 0 kelvins (absolute zero)—at such temperature, the quantum-mechanical properties of an atom are crucial. To reach low temperatures, atoms must be trapped and pre-cooled through laser cooling in a magneto-optical trap. However, to reach even lower temperatures, atoms must be exposed to evaporative cooling in a magnetic or optical trap. Today, ultracold physics could be used to study quantum phase transition, Bose–Einstein condensation (BEC), bosonic superfluidity, quantum magnetism, many-body spin dynamics, Efimov states, Bardeen-Cooper-Schrieffer (BCS) superfluidity, as well as the BEC-BCS crossover amongst other fields.