Born: 1 April 1933, Constantine, French Algeria (now Algeria)
Affiliation at the time of the award: Collège de France, Paris, France, École Normale Supérieure, Paris, France
Prize motivation: "for development of methods to cool and trap atoms with laser light"
Field: atomic physics
Prize share: 1/3
At room temperature atoms and molecules in the air move about at breakneck speed. In order for them to be studied, they need to be slowed down or chilled. During the 1980s Claude Cohen-Tannoudji, Steven Chu, and William Phillips developed different methods for this. When atoms come in contact with light particles with fixed energies, photons, their movement is affected as if they had been bumped. With the aid of laser light from different directions and adjustment of the photon's energy for Doppler effects, the atoms can be cooled to extremely low temperatures and captured in a trap.