In a familiar world of solids, liquids and gases, we find the fourth state of matter, the plasmas of lightning to the aurora borealis and fluorescent tubes at the office. Further out, minor phenomena becomes the big event in space, our shining stars are plasma being fused producing light. Not until 1924 was a fifth state of matter considered possible. Intrigued by quantum statistics, invented by the Bengali physicist, Satyendra Nath Bose from observations of light, Einstein applied Bose’s work to matter. The Bose-Einstein Condensate(BEC) was born. Was there any truth to the theory, Einstein himself wondered, that matter that could condense at ultracold temperatures into something new?
Einstein’s theory was left hanging, as a mathematical artifact, until 1938. Fritz London, a German theoretical chemist and physicist, working on helium at the same time as the Russian Pyotr Kapitsa who discovered its superfluid state at just under 2.2 K, found it behaved like Einstein’s theoretical BEC. Subsequent research confirmed London’s insight. Both stable isotopes, ordinary helium-4, and the rare helium-3 at much lower temperatures, are quantum superfluids, behaving like matter-waves or superatoms, undifferentiated matter with vastly different properties from their gas state or their ordinary bottled fluid state.