Laser cooling, evaporative cooling and Bose-Einstein condensation

Laser radiations are used to slow down atoms by the process of momentum transfer. This leads to reducing the temperature to microkelvin region. Gas phase atoms are trapped by using magnetic fields. The recent advances have led to the realization of the dream of physicists of confining the atoms and reducing their velocities to the limit imposed by quantum mechanics. A number of new experiments are possible with the cooled and trapped atoms and ions that would be useful to solve many problems of theoretical physics. Further cooling by the process of evaporative technique has led to the observation of Bose-Einstein Condensation predicted by Einstein and Rose nearly seventy-five years ago. A brief review of the method of laser cooling, magnetic trapping and evaporative cooling methods used for obtaining ultracold atoms are discussed. It is possible to obtain temperature in the nanokelvin region without using cryogenic methods thus simplifying the experimental methods to a great extent.