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Rf-induced evaporative cooling of 87Rb atoms in magnetic traps toward Bose-Einst

Speaker: Dahyun Yum Seoul national university, Korea
Time: 2013-07-01 10:00-2013-07-01 11:00
Venue: FIT-1-222


     The Bose-Einstein condensates provide wide research area in physics, i.e. studying matter wave, precision measurement, cold collisions, atoms in the lattices and etc. We also try to achieve realization of BECs with Rubidium-87 atoms to study quantum dynamical statics. In this talk, the experimental processes and results will be presented.
     A glass chamber(or 2nd chamber) in an ultra high vacuum condition below 10-11 torr was connected a stainless chamber(or 1st chamber) by a narrow pipe for differential pumping. Magneto-optically trapped cold atoms were pushed by a resonant laser from 1st chamber and then recaptured in the 2nd chamber by MOT. After pre-cooling stage – compressed MOT, molasses cooling and optical pumping – the atoms were transferred to the magnetic quadrupole potential generated by an anti-Helmholtz coil pair. For trapping and cooling Rb atoms in the magnetic trap to prevent the spin-flip loss, a time-averaged orbiting potential (TOP) trap and a hybrid type(Optical dipole potential with magnetic quadratic potential) trap were tried. The Rb atoms in magnetic traps were cooled by a forced radio-frequency evaporation. Though the phase space density could not reach the critical point of BEC, the temperature of atoms was reached to several micro-Kelvin in this experimental process. The reason why the BECs could not be achieved and the present process will be discussed.

Short Bio:

Dr. Dahyun Yum is a post doc. in Seoul national university, Korea. He has worked in the project of making Bose-Einstein condensates with 87Rb atoms mainly. He had involved in the research with parametrically driven atoms in magneto-optical trap to study various phenomena in it, i.e. multiple sub-Doppler trap, multiple basin boundaries in magnetically modulated MOT and non-equilibrium dynamics. He received ph. D degree august 2012 in physics from Seoul national university.