Gaseous Bose–Einstein Condensate Finally Observed
AUG 01, 1995
Researchers using a clever new magnetic trap have cooled a cloud of rubidium‐87 atoms to a record‐low 20 nanokelvins and achieved the Holy Grail of low‐temperature atomic physics: Bose–Einstein condensation in a gas.
About seven decades ago Satyendra Nath Bose and Albert Einstein predicted that a gas of noninteracting integer‐spin particles would condense into a macroscopic quantum state when cooled below a critical temperature. Of course Bose–Einstein condensation (BEC) has long since been seen in superfluid and superconductors, but the condensing systems in these examples are far from being noninteracting gases; relatively strong interactions between the condensing particles greatly complicate the theoretical analysis and the experimental behavior. For more than 15 years groups have been cooling and compressing clouds of atoms on a quest to produce and observe a Bose–Einstein condensate in a nearideal gas. They pushed their devices to the limit, seeking to traverse 15 orders of magnitude of phase‐space density, and as each technique proved insufficient they developed ingenious variations to create ever colder and denser states.
This article is only available in PDF format
© 1995 American Institute of Physics
