The coldest place in the Universe is in advanced physics laboratories, where sophisticated optical cooling techniques are used to produce ultra-cold groups of atoms known as Bose-Einstein Condensates (BECs) that behave like single wave-like entities, a ‘super atom’ as it were.

In 1924, Albert Einstein and the Indian physicist Satyendra Nath Bose predicted that a fifth state of matter, following solids, liquids, gases and plasma would form as a super-cooled gas that no longer behaves as individual atoms and particles but rather an entity in a single quantum state. This applies only to bosons which are particles with integer spins. Seventy years would pass before the first BEC could be produced in the lab, made possible by the emergence of ingenious laser and magnetic field techniques for isolating and slowing down the motions of atoms towards the super-cooled state.

The first sighting of a BEC was in June 1996 when Eric Cornell, Carl Wiemann and their team at the JILA laboratory in Boulder, Colorado produced the first gaseous condensate using a rarefied gas of rubidium atoms at extremely low temperatures of less than 170 billionths of a degree above absolute zero. At these low temperatures, the individual atoms condensed into the single entity as predicted by Einstein and Bose. The graphic below shows a three-dimensional sequence of snapshots in time where the atoms condensed from less dense red, yellow and green areas to very dense blue and white areas. Not long afterwards, Wolfgang Ketterle and colleagues at the Massachusetts Institute of Technology created a sodium-23 condensate.

For their contributions, Cornell, Wiemann and Ketterle received the Nobel Prize for Physics in 2001. Since then, a new race is on to exploit the wave-like behavior of BECs for developing quantum computers, super-precise atomic clocks and atomic lasers.