A Bose–Einstein Condensate (BEC) is a state of matter (sometimes called the fifth state of matter) which is typically formed when a gas of bosons at low densities is cooled to temperatures very close to absolute zero (-273.15 °C).
Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which point microscopic quantum phenomena, particularly wavefunction interference, become apparent macroscopically.
This state was first predicted by Albert Einstein following a paper written by Satyendra Nath Bose.