In quantum physics, what state of matter forms when bosons occupy one ground state at ultralow temperature?

In quantum physics, a Bose–Einstein condensate forms when bosons occupy one ground state at ultralow temperature. In this state, a large number of particles can behave collectively as a single coherent quantum system.

Satyendra Nath Bose developed the statistics for photons in 1924, and Albert Einstein extended the work in 1924 and 1925 to predict condensation of noninteracting bosonic atoms. The effect requires temperatures close to absolute zero because ordinary thermal motion would otherwise disrupt the collective state.

Eric Cornell and Carl Wieman created the first dilute atomic Bose–Einstein condensate in 1995 using rubidium-87; Wolfgang Ketterle produced another early condensate using sodium. Cornell, Wieman, and Ketterle shared the 2001 Nobel Prize in Physics. A condensate is not simply a cold conventional gas: its particles share a macroscopic wave function and can display interference and superfluid behavior.