In order to create a gas condensate, the atoms must be strongly cooled: from 300 K to only a few millionths of a degree to absolute zero! In order to do that, we mainly use laser light because the force applied on the atoms is a million times stronger than gravity. It was hence the technological development of lasers applied to atom manipulation that enabled the advances made in the 90s.
It takes actually two stages to cool atoms. First, laser beams slow down the atoms: photons (light particles) are sent against atoms, the interactions slow the atoms (down to temperatures close to ten millionths of a degree from absolute zero). To cool the atoms more, we need to “blow” on the gas to get rid of the hottest particles as we do to cool a cup of tea. This technique called “evaporation technique” enables to reach the necessary temperature of several billionths of a degree from absolute zero.
