Sympathetic cooling is a process in which particles of one type cool particles of another type.
Typically, atomic ions that can be directly laser cooled are used to cool nearby ions or atoms, by way of their mutual Coulomb interaction. This technique allows cooling of ions and atoms that can't be cooled directly by laser cooling. This includes most molecular ion species, especially large organic molecules. However, sympathetic cooling is most efficient when the mass/charge ratios of the sympathetic- and laser-cooled ions are similar.
The cooling of neutral atoms in this manner was first demonstrated by Christopher Myatt et al. in 1997. Here, a technique with electric and magnetic fields were used, where atoms with spin in one direction were more weakly confined than those with spin in the opposite direction. The weakly confined atoms with a high kinetic energy were allowed to more easily escape, lowering the total kinetic energy, resulting in a cooling of the strongly confined atoms. Myatt et al. also showed the utility of their version of sympathetic cooling for the creation of Bose–Einstein condensates
Famous quotes containing the words cooling and/or sympathetic:
“So God stepped over to the edge of the world
And He spat out the seven seas;
He batted His eyes, and the lightnings flashed;
He clapped His hands, and the thunders rolled;
And the waters above the earth came down,
The cooling waters came down.”
—James Weldon Johnson (18711938)
“It is a doctrine alike of the oldest and of the newest philosophy, that man is one, and that you cannot injure any member, without a sympathetic injury to all the members.”
—Ralph Waldo Emerson (18031882)