Observation of Bose-Einstein Condensation in a Dilute, Atomic Vapor below 200 nanokelvins
M H. Anderson, J R. Ensher, M R. Matthews, C E. Wieman, Eric A. Cornell
We have produced a Bose-Einstein condensate in a vapor of rubidium-87 atoms confined by magnetic fields and evaporatively cooled. The condensate fraction first appears near a temperature of 180 nK and a number density of 2.5 X1012 cm-3 and can be preserved in our trap for more than 15 seconds. We see three primary signatures of Bose-Einstein condensation. (1) On top of the usual broad thermal velocity distribution, a narrow peak appears that is centered at zero velocity. (2) The fraction of the atoms that are in this low-velocity peak increase discontinuously as the sample temperature is lowered. (3) The peak exhibits a nonthermal, anisotropic velocity distribution expected of the minimum-energy quantum state of our magnetic trap, in contrast to the isotropic, thermal velocity distribution observed in the broad uncondensed fraction.
Bose-Einstein condensation, evaporative cooling, laser cooling, magnetic trapping
, Ensher, J.
, Matthews, M.
, Wieman, C.
and Cornell, E.
Observation of Bose-Einstein Condensation in a Dilute, Atomic Vapor below 200 nanokelvins, Science
(Accessed March 28, 2023)