When the atom trap is
filled, the next step in the cooling process begins.
One of this year’s Nobel Laureates, Carl E.
Wieman, proposed around 1990 that, after laser
cooling, the light should be turned off and what is
cooling should be applied to the
magnetically confined cloud. In this technique, the
edge of the ”pit” in which the atoms are
confined is lowered so that the fastest ones can
escape. Those that remain then have a lower
temperature. This is like what takes place in a cup
of hot coffee: the fastest water molecules leave the
surface as steam.