Evaporative cooler

Evaporative cooling is a class of cooling methods, which are based on the remove of a thermodynamic system of particles in each case the most energetic. It is related to the evaporative cooling, and is sometimes also referred to as.

When there is an interaction between the particles in the system, they can thermalize, that is, it forms a new thermodynamic equilibrium out. Since the average power of the remaining particles is less than in the original system, the temperature of the new steady state is low. By repeated application of this process can produce very low temperatures, however, this case loses a large part of the particles.

Evaporative cooling methods are used in quantum optics for the generation of gases at temperatures near absolute zero. The gas is then in a magnetic or optical trap, removing the particles from the case carried out either alone or, more efficiently, by a lowering of the trap potential, or a transition of the particles to other internal quantum states that are not caught in the trap.

Evaporative cooling, eg by radio -frequency transitions between different Zeeman states in a magnetic trap, is the crucial step for the production of Bose -Einstein condensates.

Clearly, this is comparable to the cooling of a cup of coffee by " blowing ". Among other hot particles are removed near the liquid surface so that more hot particles can leave the liquid and pass into the vapor phase. The fluid loses some heat energy and cools down.

• Quantum Optics
• Cooling methods