"A short video explaining how a Bose-Einstein Condensate of sodium atoms is created in lab at MIT. Using highly focused, single frequency lasers it is possible to cool the single sodium atoms, negating their thermal vibrations by inducing electronic transitions which effectively "pushes" them into place. This brings the atoms down to millikelivn temperatures.
To achieve nanokelvin temperatures, magnetic fields are used to trap the atoms in a well or cup so that the atomic resonance of the atoms begins to match the frequency of the laser light so that, like in a cup of coffee or tea, the hottest atoms are boiled off the surface by "blowing" on the atoms with polarized laser light. This makes the atoms that are in resonance with the light move towards the center, leaving the hotter atoms to boil off. This then shrinks the gas cloud into a supercool sphere."