Cooling Bose-Einstein Condensates Below 500 Picokelvin
A. E. Leanhardt,*
T. A. Pasquini,
M. Saba,
A. Schirotzek,
Y. Shin,
D. Kielpinski,
D. E. Pritchard,
W. Ketterle
Spin-polarized gaseous Bose-Einstein condensates were confined
by a combination of gravitational and magnetic forces. The partially
condensed atomic vapors were adiabatically decompressed by weakening
the gravito-magnetic trap to a mean frequency of 1hertz, then
evaporatively reduced in size to 2500 atoms. This lowered the
peak condensate density to 5
x 10
10 atoms per cubic centimeter
and cooled the entire cloud in all three dimensions to a kinetic
temperature of 450 ± 80 picokelvin. Such spin-polarized,
dilute, and ultracold gases are important for spectroscopy,
metrology, and atom optics.
* To whom correspondence should be addressed. E-mail: ael{at}mit.edu
