Bose-Einstein Condensation at the Kyoto University Quantum Optics Laboratory
We have observed Bose-Einstein condensation in
87Rb atoms.
The experiment is performed by a double MOT configuration with
a clover-leaf magnetic trap.
Parameters of the experiment are as follows:
Loading time of MOT: about 2.5`3 min
Number of atoms in MOT: 4 x 109
Axial curvature of clover leaf trap: 181 G/cm
Radial gradient of clover leaf trap: 87 G/cm2
Bias field at the center of the trap: 0.4 G
Axial oscillation frequencies: 15 Hz
Radial oscillation frequencies: 360 Hz
Number of atoms in the magnetic trap: 1.5 x 109
Lifetime of the magnetic trap: 90s
Temperature in the magnetic trap after compression: about 1 mK
Level for magnetic trapping: F=2, mF=+2
Evaporation time: about 45 s
Number of atoms in the condensate: up to 7 x 105

Time of Flight image of a Bose-Einstein condensate.
The spatial distribution of the transmission of a probe beam is plotted
along the vertical axis.
The central red area corresponds to the condensate,surrounded by the broader
blue area of the non-condensated atoms.
The flight time is 20ms.
Multiply charged vortex (winding number 4) by inverting magnetic field of the trap.

Parameters of the experiment are as follows:
Bias field at the center of the trap (Before reversing magnetic field):0.4G
Reversing time: 2.2ms
Bias field at the center of the trap (After reversing magnetic field): -0.2G
present member
Yoshiro Takahashi(staff)
Masayuki Okano(Doctor 1st)
previous member
Kentaro Kasa
Mitsutaka Kumakura(in Fukui University)
Tsutomu Yabuzaki(in Osaka Electronic-Communication University)
Takashi Hirotani
Yukari Shirahata
Nobuhiko Shima
Noriyuki Kimura
Tsuyoshi Kuwamoto(in Gakushuin University)
Kenji Toyoda(in Osaka University)
If you have any comments, please mail to:
Y. Takahashi (yitk@yagura.scphys.kyoto-u.ac.jp)
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