Laser Research

Cold atomic calculations

Print edition : June 22, 2018

Artist’s conception of the Cold Atom Laboratory (CAL) is a new facility that will create a spot 10 billion times colder than the vacuum of space, and will help in the study of novel quantum phenomena. Photo: NASA/JPL

Among the experimental payloads that NASA sent to the International Space Station (ISS) on May 21 is an ice chest-sized apparatus called Cold Atom Laboratory (CAL) which will create a temperature that is 10 billion times colder than the vacuum of space to study the strange quantum behaviour of atoms.

Designed by NASA’s Jet Propulsion Laboratory (JPL), CAL will use lasers and magnets to produce clouds of ultra-cooled atoms very close to absolute zero (-273.15 °C), but not quite because at absolute zero all motion ceases. These clouds of atoms are what are called as Bose-Einstein Condensates (BEC), a state predicted by Einstein in 1925 from the work of the Indian scientist S.N. Bose. This state was observed in a Nobel Prize-winning work in 1995 in a gas of ultra-cold rubidium atoms.

Atoms in BEC, which move very slowly, display quantum characteristics at relatively large scales, allowing researchers to explore this strange domain. However, on the earth, freely evolving BECs are dragged down by gravity and can, therefore, typically be observed only for a fraction of a second. But in the microgravity environment of the ISS, BEC can be cooled down with lasers and magnets to a tenth of a billionth of a degree above absolute zero until they are almost motionless, and can be observed for up to 10 seconds. The results of this research could potentially lead to a number of improved technologies, including sensors, quantum computers and atomic clocks used in spacecraft navigation.